[v3,net-next,1/4] net: qos: introduce a gate control flow action

Introduce a ingress frame gate control flow action.
Tc gate action does the work like this:
Assume there is a gate allow specified ingress frames can be passed at
specific time slot, and be dropped at specific time slot. Tc filter
chooses the ingress frames, and tc gate action would specify what slot
does these frames can be passed to device and what time slot would be
dropped.
Tc gate action would provide an entry list to tell how much time gate
keep open and how much time gate keep state close. Gate action also
assign a start time to tell when the entry list start. Then driver would
repeat the gate entry list cyclically.
For the software simulation, gate action requires the user assign a time
clock type.

Below is the setting example in user space. Tc filter a stream source ip
address is 192.168.0.20 and gate action own two time slots. One is last
200ms gate open let frame pass another is last 100ms gate close let
frames dropped. When the frames have passed total frames over 8000000
bytes, frames will be dropped in one 200000000ns time slot.

> tc qdisc add dev eth0 ingress

> tc filter add dev eth0 parent ffff: protocol ip \
	   flower src_ip 192.168.0.20 \
	   action gate index 2 clockid CLOCK_TAI \
	   sched-entry open 200000000 -1 8000000 \
	   sched-entry close 100000000 -1 -1

> tc chain del dev eth0 ingress chain 0

"sched-entry" follow the name taprio style. Gate state is
"open"/"close". Follow with period nanosecond. Then next item is internal
priority value means which ingress queue should put. "-1" means
wildcard. The last value optional specifies the maximum number of
MSDU octets that are permitted to pass the gate during the specified
time interval.
Base-time is not set will be 0 as default, as result start time would
be ((N + 1) * cycletime) which is the minimal of future time.

Below example shows filtering a stream with destination mac address is
10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The gate
action would run with one close time slot which means always keep close.
The time cycle is total 200000000ns. The base-time would calculate by:

 1357000000000 + (N + 1) * cycletime

When the total value is the future time, it will be the start time.
The cycletime here would be 200000000ns for this case.

> tc filter add dev eth0 parent ffff:  protocol ip \
	   flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
	   action gate index 12 base-time 1357000000000 \
	   sched-entry close 200000000 -1 -1 \
	   clockid CLOCK_TAI

Signed-off-by: Po Liu <Po.Liu@nxp.com>
---
 include/net/tc_act/tc_gate.h        |  54 +++
 include/uapi/linux/pkt_cls.h        |   1 +
 include/uapi/linux/tc_act/tc_gate.h |  47 ++
 net/sched/Kconfig                   |  13 +
 net/sched/Makefile                  |   1 +
 net/sched/act_gate.c                | 647 ++++++++++++++++++++++++++++
 6 files changed, 763 insertions(+)
 create mode 100644 include/net/tc_act/tc_gate.h
 create mode 100644 include/uapi/linux/tc_act/tc_gate.h
 create mode 100644 net/sched/act_gate.c

Hi Po,

On Wed 22 Apr 2020 at 05:48, Po Liu <Po.Liu@nxp.com> wrote:
> Introduce a ingress frame gate control flow action.
> Tc gate action does the work like this:
> Assume there is a gate allow specified ingress frames can be passed at
> specific time slot, and be dropped at specific time slot. Tc filter
> chooses the ingress frames, and tc gate action would specify what slot
> does these frames can be passed to device and what time slot would be
> dropped.
> Tc gate action would provide an entry list to tell how much time gate
> keep open and how much time gate keep state close. Gate action also
> assign a start time to tell when the entry list start. Then driver would
> repeat the gate entry list cyclically.
> For the software simulation, gate action requires the user assign a time
> clock type.
>
> Below is the setting example in user space. Tc filter a stream source ip
> address is 192.168.0.20 and gate action own two time slots. One is last
> 200ms gate open let frame pass another is last 100ms gate close let
> frames dropped. When the frames have passed total frames over 8000000
> bytes, frames will be dropped in one 200000000ns time slot.
>
>> tc qdisc add dev eth0 ingress
>
>> tc filter add dev eth0 parent ffff: protocol ip \
> 	   flower src_ip 192.168.0.20 \
> 	   action gate index 2 clockid CLOCK_TAI \
> 	   sched-entry open 200000000 -1 8000000 \
> 	   sched-entry close 100000000 -1 -1
>
>> tc chain del dev eth0 ingress chain 0
>
> "sched-entry" follow the name taprio style. Gate state is
> "open"/"close". Follow with period nanosecond. Then next item is internal
> priority value means which ingress queue should put. "-1" means
> wildcard. The last value optional specifies the maximum number of
> MSDU octets that are permitted to pass the gate during the specified
> time interval.
> Base-time is not set will be 0 as default, as result start time would
> be ((N + 1) * cycletime) which is the minimal of future time.
>
> Below example shows filtering a stream with destination mac address is
> 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The gate
> action would run with one close time slot which means always keep close.
> The time cycle is total 200000000ns. The base-time would calculate by:
>
>  1357000000000 + (N + 1) * cycletime
>
> When the total value is the future time, it will be the start time.
> The cycletime here would be 200000000ns for this case.
>
>> tc filter add dev eth0 parent ffff:  protocol ip \
> 	   flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
> 	   action gate index 12 base-time 1357000000000 \
> 	   sched-entry close 200000000 -1 -1 \
> 	   clockid CLOCK_TAI
>
> Signed-off-by: Po Liu <Po.Liu@nxp.com>
> ---
>  include/net/tc_act/tc_gate.h        |  54 +++
>  include/uapi/linux/pkt_cls.h        |   1 +
>  include/uapi/linux/tc_act/tc_gate.h |  47 ++
>  net/sched/Kconfig                   |  13 +
>  net/sched/Makefile                  |   1 +
>  net/sched/act_gate.c                | 647 ++++++++++++++++++++++++++++
>  6 files changed, 763 insertions(+)
>  create mode 100644 include/net/tc_act/tc_gate.h
>  create mode 100644 include/uapi/linux/tc_act/tc_gate.h
>  create mode 100644 net/sched/act_gate.c
>
> diff --git a/include/net/tc_act/tc_gate.h b/include/net/tc_act/tc_gate.h
> new file mode 100644
> index 000000000000..b0ace55b2aaa
> --- /dev/null
> +++ b/include/net/tc_act/tc_gate.h
> @@ -0,0 +1,54 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright 2020 NXP */
> +
> +#ifndef __NET_TC_GATE_H
> +#define __NET_TC_GATE_H
> +
> +#include <net/act_api.h>
> +#include <linux/tc_act/tc_gate.h>
> +
> +struct tcfg_gate_entry {
> +	int			index;
> +	u8			gate_state;
> +	u32			interval;
> +	s32			ipv;
> +	s32			maxoctets;
> +	struct list_head	list;
> +};
> +
> +struct tcf_gate_params {
> +	s32			tcfg_priority;
> +	u64			tcfg_basetime;
> +	u64			tcfg_cycletime;
> +	u64			tcfg_cycletime_ext;
> +	u32			tcfg_flags;
> +	s32			tcfg_clockid;
> +	size_t			num_entries;
> +	struct list_head	entries;
> +};
> +
> +#define GATE_ACT_GATE_OPEN	BIT(0)
> +#define GATE_ACT_PENDING	BIT(1)
> +struct gate_action {
> +	struct tcf_gate_params param;
> +	spinlock_t entry_lock;
> +	u8 current_gate_status;
> +	ktime_t current_close_time;
> +	u32 current_entry_octets;
> +	s32 current_max_octets;
> +	struct tcfg_gate_entry __rcu *next_entry;
> +	struct hrtimer hitimer;
> +	enum tk_offsets tk_offset;
> +	struct rcu_head rcu;
> +};
> +
> +struct tcf_gate {
> +	struct tc_action		common;
> +	struct gate_action __rcu	*actg;
> +};
> +#define to_gate(a) ((struct tcf_gate *)a)
> +
> +#define get_gate_param(act) ((struct tcf_gate_params *)act)
> +#define get_gate_action(p) ((struct gate_action *)p)
> +
> +#endif
> diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
> index 9f06d29cab70..fc672b232437 100644
> --- a/include/uapi/linux/pkt_cls.h
> +++ b/include/uapi/linux/pkt_cls.h
> @@ -134,6 +134,7 @@ enum tca_id {
>  	TCA_ID_CTINFO,
>  	TCA_ID_MPLS,
>  	TCA_ID_CT,
> +	TCA_ID_GATE,
>  	/* other actions go here */
>  	__TCA_ID_MAX = 255
>  };
> diff --git a/include/uapi/linux/tc_act/tc_gate.h b/include/uapi/linux/tc_act/tc_gate.h
> new file mode 100644
> index 000000000000..f214b3a6d44f
> --- /dev/null
> +++ b/include/uapi/linux/tc_act/tc_gate.h
> @@ -0,0 +1,47 @@
> +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> +/* Copyright 2020 NXP */
> +
> +#ifndef __LINUX_TC_GATE_H
> +#define __LINUX_TC_GATE_H
> +
> +#include <linux/pkt_cls.h>
> +
> +struct tc_gate {
> +	tc_gen;
> +};
> +
> +enum {
> +	TCA_GATE_ENTRY_UNSPEC,
> +	TCA_GATE_ENTRY_INDEX,
> +	TCA_GATE_ENTRY_GATE,
> +	TCA_GATE_ENTRY_INTERVAL,
> +	TCA_GATE_ENTRY_IPV,
> +	TCA_GATE_ENTRY_MAX_OCTETS,
> +	__TCA_GATE_ENTRY_MAX,
> +};
> +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
> +
> +enum {
> +	TCA_GATE_ONE_ENTRY_UNSPEC,
> +	TCA_GATE_ONE_ENTRY,
> +	__TCA_GATE_ONE_ENTRY_MAX,
> +};
> +#define TCA_GATE_ONE_ENTRY_MAX (__TCA_GATE_ONE_ENTRY_MAX - 1)
> +
> +enum {
> +	TCA_GATE_UNSPEC,
> +	TCA_GATE_TM,
> +	TCA_GATE_PARMS,
> +	TCA_GATE_PAD,
> +	TCA_GATE_PRIORITY,
> +	TCA_GATE_ENTRY_LIST,
> +	TCA_GATE_BASE_TIME,
> +	TCA_GATE_CYCLE_TIME,
> +	TCA_GATE_CYCLE_TIME_EXT,
> +	TCA_GATE_FLAGS,
> +	TCA_GATE_CLOCKID,
> +	__TCA_GATE_MAX,
> +};
> +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
> +
> +#endif
> diff --git a/net/sched/Kconfig b/net/sched/Kconfig
> index bfbefb7bff9d..1314549c7567 100644
> --- a/net/sched/Kconfig
> +++ b/net/sched/Kconfig
> @@ -981,6 +981,19 @@ config NET_ACT_CT
>  	  To compile this code as a module, choose M here: the
>  	  module will be called act_ct.
>  
> +config NET_ACT_GATE
> +	tristate "Frame gate entry list control tc action"
> +	depends on NET_CLS_ACT
> +	help
> +	  Say Y here to allow to control the ingress flow to be passed at
> +	  specific time slot and be dropped at other specific time slot by
> +	  the gate entry list. The manipulation will simulate the IEEE
> +	  802.1Qci stream gate control behavior.
> +
> +	  If unsure, say N.
> +	  To compile this code as a module, choose M here: the
> +	  module will be called act_gate.
> +
>  config NET_IFE_SKBMARK
>  	tristate "Support to encoding decoding skb mark on IFE action"
>  	depends on NET_ACT_IFE
> diff --git a/net/sched/Makefile b/net/sched/Makefile
> index 31c367a6cd09..66bbf9a98f9e 100644
> --- a/net/sched/Makefile
> +++ b/net/sched/Makefile
> @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)	+= act_meta_skbprio.o
>  obj-$(CONFIG_NET_IFE_SKBTCINDEX)	+= act_meta_skbtcindex.o
>  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
>  obj-$(CONFIG_NET_ACT_CT)	+= act_ct.o
> +obj-$(CONFIG_NET_ACT_GATE)	+= act_gate.o
>  obj-$(CONFIG_NET_SCH_FIFO)	+= sch_fifo.o
>  obj-$(CONFIG_NET_SCH_CBQ)	+= sch_cbq.o
>  obj-$(CONFIG_NET_SCH_HTB)	+= sch_htb.o
> diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c
> new file mode 100644
> index 000000000000..e932f402b4f1
> --- /dev/null
> +++ b/net/sched/act_gate.c
> @@ -0,0 +1,647 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* Copyright 2020 NXP */
> +
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/string.h>
> +#include <linux/errno.h>
> +#include <linux/skbuff.h>
> +#include <linux/rtnetlink.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <net/act_api.h>
> +#include <net/netlink.h>
> +#include <net/pkt_cls.h>
> +#include <net/tc_act/tc_gate.h>
> +
> +static unsigned int gate_net_id;
> +static struct tc_action_ops act_gate_ops;
> +
> +static ktime_t gate_get_time(struct gate_action *gact)
> +{
> +	ktime_t mono = ktime_get();
> +
> +	switch (gact->tk_offset) {
> +	case TK_OFFS_MAX:
> +		return mono;
> +	default:
> +		return ktime_mono_to_any(mono, gact->tk_offset);
> +	}
> +
> +	return KTIME_MAX;
> +}
> +
> +static int gate_get_start_time(struct gate_action *gact, ktime_t *start)
> +{
> +	struct tcf_gate_params *param = get_gate_param(gact);
> +	ktime_t now, base, cycle;
> +	u64 n;
> +
> +	base = ns_to_ktime(param->tcfg_basetime);
> +	now = gate_get_time(gact);
> +
> +	if (ktime_after(base, now)) {
> +		*start = base;
> +		return 0;
> +	}
> +
> +	cycle = param->tcfg_cycletime;
> +
> +	/* cycle time should not be zero */
> +	if (WARN_ON(!cycle))
> +		return -EFAULT;

Looking at the init code it seems that this value can be set to 0
directly from netlink packet without further validation, which would
allow user to trigger warning here.

> +
> +	n = div64_u64(ktime_sub_ns(now, base), cycle);
> +	*start = ktime_add_ns(base, (n + 1) * cycle);
> +	return 0;
> +}
> +
> +static void gate_start_timer(struct gate_action *gact, ktime_t start)
> +{
> +	ktime_t expires;
> +
> +	expires = hrtimer_get_expires(&gact->hitimer);
> +	if (expires == 0)
> +		expires = KTIME_MAX;
> +
> +	start = min_t(ktime_t, start, expires);
> +
> +	hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS);
> +}
> +
> +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer)
> +{
> +	struct gate_action *gact = container_of(timer, struct gate_action,
> +						hitimer);
> +	struct tcf_gate_params *p = get_gate_param(gact);
> +	struct tcfg_gate_entry *next;
> +	ktime_t close_time, now;
> +
> +	spin_lock(&gact->entry_lock);
> +
> +	next = rcu_dereference_protected(gact->next_entry,
> +					 lockdep_is_held(&gact->entry_lock));
> +
> +	/* cycle start, clear pending bit, clear total octets */
> +	gact->current_gate_status = next->gate_state ? GATE_ACT_GATE_OPEN : 0;
> +	gact->current_entry_octets = 0;
> +	gact->current_max_octets = next->maxoctets;
> +
> +	gact->current_close_time = ktime_add_ns(gact->current_close_time,
> +						next->interval);
> +
> +	close_time = gact->current_close_time;
> +
> +	if (list_is_last(&next->list, &p->entries))
> +		next = list_first_entry(&p->entries,
> +					struct tcfg_gate_entry, list);
> +	else
> +		next = list_next_entry(next, list);
> +
> +	now = gate_get_time(gact);
> +
> +	if (ktime_after(now, close_time)) {
> +		ktime_t cycle, base;
> +		u64 n;
> +
> +		cycle = p->tcfg_cycletime;
> +		base = ns_to_ktime(p->tcfg_basetime);
> +		n = div64_u64(ktime_sub_ns(now, base), cycle);
> +		close_time = ktime_add_ns(base, (n + 1) * cycle);
> +	}
> +
> +	rcu_assign_pointer(gact->next_entry, next);
> +	spin_unlock(&gact->entry_lock);

I have couple of question about synchronization here:

- Why do you need next_entry to be rcu pointer? It is only assigned here
with entry_lock protection and in init code before action is visible to
concurrent users. I don't see any unlocked rcu-protected readers here
that could benefit from it.

- Why create dedicated entry_lock instead of using already existing
per-action tcf_lock?

> +
> +	hrtimer_set_expires(&gact->hitimer, close_time);
> +
> +	return HRTIMER_RESTART;
> +}
> +
> +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
> +			struct tcf_result *res)
> +{
> +	struct tcf_gate *g = to_gate(a);
> +	struct gate_action *gact;
> +	int action;
> +
> +	tcf_lastuse_update(&g->tcf_tm);
> +	bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
> +
> +	action = READ_ONCE(g->tcf_action);
> +	rcu_read_lock();

Action fastpath is already rcu read lock protected, you don't need to
manually obtain it.

> +	gact = rcu_dereference_bh(g->actg);
> +	if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {

Can't current_gate_status be concurrently modified by timer callback?
This function doesn't use entry_lock to synchronize with timer.

> +		rcu_read_unlock();
> +		return action;
> +	}
> +
> +	if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))

...and here

> +		goto drop;
> +
> +	if (gact->current_max_octets >= 0) {
> +		gact->current_entry_octets += qdisc_pkt_len(skb);
> +		if (gact->current_entry_octets > gact->current_max_octets) {

here also.

> +			qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));

Please use tcf_action_inc_overlimit_qstats() and other wrappers for
stats. Otherwise it will crash if user passes
TCA_ACT_FLAGS_NO_PERCPU_STATS flag.

> +			goto drop;
> +		}
> +	}
> +	rcu_read_unlock();
> +
> +	return action;
> +drop:
> +	rcu_read_unlock();
> +	qstats_drop_inc(this_cpu_ptr(g->common.cpu_qstats));
> +	return TC_ACT_SHOT;
> +}
> +
> +static const struct nla_policy entry_policy[TCA_GATE_ENTRY_MAX + 1] = {
> +	[TCA_GATE_ENTRY_INDEX]		= { .type = NLA_U32 },
> +	[TCA_GATE_ENTRY_GATE]		= { .type = NLA_FLAG },
> +	[TCA_GATE_ENTRY_INTERVAL]	= { .type = NLA_U32 },
> +	[TCA_GATE_ENTRY_IPV]		= { .type = NLA_S32 },
> +	[TCA_GATE_ENTRY_MAX_OCTETS]	= { .type = NLA_S32 },
> +};
> +
> +static const struct nla_policy gate_policy[TCA_GATE_MAX + 1] = {
> +	[TCA_GATE_PARMS]		= { .len = sizeof(struct tc_gate),
> +					    .type = NLA_EXACT_LEN },
> +	[TCA_GATE_PRIORITY]		= { .type = NLA_S32 },
> +	[TCA_GATE_ENTRY_LIST]		= { .type = NLA_NESTED },
> +	[TCA_GATE_BASE_TIME]		= { .type = NLA_U64 },
> +	[TCA_GATE_CYCLE_TIME]		= { .type = NLA_U64 },
> +	[TCA_GATE_CYCLE_TIME_EXT]	= { .type = NLA_U64 },
> +	[TCA_GATE_FLAGS]		= { .type = NLA_U32 },
> +	[TCA_GATE_CLOCKID]		= { .type = NLA_S32 },
> +};
> +
> +static int fill_gate_entry(struct nlattr **tb, struct tcfg_gate_entry *entry,
> +			   struct netlink_ext_ack *extack)
> +{
> +	u32 interval = 0;
> +
> +	entry->gate_state = nla_get_flag(tb[TCA_GATE_ENTRY_GATE]);
> +
> +	if (tb[TCA_GATE_ENTRY_INTERVAL])
> +		interval = nla_get_u32(tb[TCA_GATE_ENTRY_INTERVAL]);
> +
> +	if (interval == 0) {
> +		NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
> +		return -EINVAL;
> +	}
> +
> +	entry->interval = interval;
> +
> +	if (tb[TCA_GATE_ENTRY_IPV])
> +		entry->ipv = nla_get_s32(tb[TCA_GATE_ENTRY_IPV]);
> +	else
> +		entry->ipv = -1;
> +
> +	if (tb[TCA_GATE_ENTRY_MAX_OCTETS])
> +		entry->maxoctets = nla_get_s32(tb[TCA_GATE_ENTRY_MAX_OCTETS]);
> +	else
> +		entry->maxoctets = -1;
> +
> +	return 0;
> +}
> +
> +static int parse_gate_entry(struct nlattr *n, struct  tcfg_gate_entry *entry,
> +			    int index, struct netlink_ext_ack *extack)
> +{
> +	struct nlattr *tb[TCA_GATE_ENTRY_MAX + 1] = { };
> +	int err;

> +	err = nla_parse_nested(tb, TCA_GATE_ENTRY_MAX, n, entry_policy, extack);
> +	if (err < 0) {
> +		NL_SET_ERR_MSG(extack, "Could not parse nested entry");
> +		return -EINVAL;
> +	}
> +
> +	entry->index = index;
> +
> +	return fill_gate_entry(tb, entry, extack);
> +}
> +
> +static int parse_gate_list(struct nlattr *list_attr,
> +			   struct tcf_gate_params *sched,
> +			   struct netlink_ext_ack *extack)
> +{
> +	struct tcfg_gate_entry *entry, *e;
> +	struct nlattr *n;
> +	int err, rem;
> +	int i = 0;
> +
> +	if (!list_attr)
> +		return -EINVAL;
> +
> +	nla_for_each_nested(n, list_attr, rem) {
> +		if (nla_type(n) != TCA_GATE_ONE_ENTRY) {
> +			NL_SET_ERR_MSG(extack, "Attribute isn't type 'entry'");
> +			continue;
> +		}
> +
> +		entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> +		if (!entry) {
> +			NL_SET_ERR_MSG(extack, "Not enough memory for entry");
> +			err = -ENOMEM;
> +			goto release_list;
> +		}
> +
> +		err = parse_gate_entry(n, entry, i, extack);
> +		if (err < 0) {
> +			kfree(entry);
> +			goto release_list;
> +		}
> +
> +		list_add_tail(&entry->list, &sched->entries);
> +		i++;
> +	}
> +
> +	sched->num_entries = i;
> +
> +	return i;
> +
> +release_list:
> +	list_for_each_entry_safe(entry, e, &sched->entries, list) {
> +		list_del(&entry->list);
> +		kfree(entry);
> +	}
> +
> +	return err;
> +}
> +
> +static int tcf_gate_init(struct net *net, struct nlattr *nla,
> +			 struct nlattr *est, struct tc_action **a,
> +			 int ovr, int bind, bool rtnl_held,
> +			 struct tcf_proto *tp, u32 flags,
> +			 struct netlink_ext_ack *extack)
> +{
> +	struct tc_action_net *tn = net_generic(net, gate_net_id);
> +	enum tk_offsets tk_offset = TK_OFFS_TAI;
> +	struct nlattr *tb[TCA_GATE_MAX + 1];
> +	struct tcf_chain *goto_ch = NULL;
> +	struct tcfg_gate_entry *next;
> +	struct tcf_gate_params *p;
> +	struct gate_action *gact;
> +	s32 clockid = CLOCK_TAI;
> +	struct tc_gate *parm;
> +	struct tcf_gate *g;
> +	int ret = 0, err;
> +	u64 basetime = 0;
> +	u32 gflags = 0;
> +	s32 prio = -1;
> +	ktime_t start;
> +	u32 index;
> +
> +	if (!nla)
> +		return -EINVAL;
> +
> +	err = nla_parse_nested(tb, TCA_GATE_MAX, nla, gate_policy, extack);
> +	if (err < 0)
> +		return err;
> +
> +	if (!tb[TCA_GATE_PARMS])
> +		return -EINVAL;
> +	parm = nla_data(tb[TCA_GATE_PARMS]);
> +	index = parm->index;
> +	err = tcf_idr_check_alloc(tn, &index, a, bind);
> +	if (err < 0)
> +		return err;
> +
> +	if (err && bind)
> +		return 0;
> +
> +	if (!err) {
> +		ret = tcf_idr_create_from_flags(tn, index, est, a,
> +						&act_gate_ops, bind, flags);
> +		if (ret) {
> +			tcf_idr_cleanup(tn, index);
> +			return ret;
> +		}
> +
> +		ret = ACT_P_CREATED;
> +	} else if (!ovr) {
> +		tcf_idr_release(*a, bind);
> +		return -EEXIST;
> +	}
> +
> +	if (tb[TCA_GATE_PRIORITY])
> +		prio = nla_get_s32(tb[TCA_GATE_PRIORITY]);
> +
> +	if (tb[TCA_GATE_BASE_TIME])
> +		basetime = nla_get_u64(tb[TCA_GATE_BASE_TIME]);
> +
> +	if (tb[TCA_GATE_FLAGS])
> +		gflags = nla_get_u32(tb[TCA_GATE_FLAGS]);
> +
> +	if (tb[TCA_GATE_CLOCKID]) {
> +		clockid = nla_get_s32(tb[TCA_GATE_CLOCKID]);
> +		switch (clockid) {
> +		case CLOCK_REALTIME:
> +			tk_offset = TK_OFFS_REAL;
> +			break;
> +		case CLOCK_MONOTONIC:
> +			tk_offset = TK_OFFS_MAX;
> +			break;
> +		case CLOCK_BOOTTIME:
> +			tk_offset = TK_OFFS_BOOT;
> +			break;
> +		case CLOCK_TAI:
> +			tk_offset = TK_OFFS_TAI;
> +			break;
> +		default:
> +			NL_SET_ERR_MSG(extack, "Invalid 'clockid'");
> +			goto release_idr;
> +		}
> +	}
> +
> +	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
> +	if (err < 0)
> +		goto release_idr;
> +
> +	g = to_gate(*a);
> +
> +	gact = kzalloc(sizeof(*gact), GFP_KERNEL);
> +	if (!gact) {
> +		err = -ENOMEM;
> +		goto put_chain;
> +	}
> +
> +	p = get_gate_param(gact);
> +
> +	INIT_LIST_HEAD(&p->entries);
> +	if (tb[TCA_GATE_ENTRY_LIST]) {
> +		err = parse_gate_list(tb[TCA_GATE_ENTRY_LIST], p, extack);
> +		if (err < 0)
> +			goto release_mem;
> +	}
> +
> +	if (tb[TCA_GATE_CYCLE_TIME]) {
> +		p->tcfg_cycletime = nla_get_u64(tb[TCA_GATE_CYCLE_TIME]);
> +	} else {
> +		struct tcfg_gate_entry *entry;
> +		ktime_t cycle = 0;
> +
> +		list_for_each_entry(entry, &p->entries, list)
> +			cycle = ktime_add_ns(cycle, entry->interval);
> +		p->tcfg_cycletime = cycle;
> +	}
> +
> +	if (tb[TCA_GATE_CYCLE_TIME_EXT])
> +		p->tcfg_cycletime_ext =
> +			nla_get_u64(tb[TCA_GATE_CYCLE_TIME_EXT]);
> +
> +	p->tcfg_priority = prio;
> +	p->tcfg_basetime = basetime;
> +	p->tcfg_clockid = clockid;
> +	p->tcfg_flags = gflags;
> +
> +	gact->tk_offset = tk_offset;
> +	spin_lock_init(&gact->entry_lock);
> +	hrtimer_init(&gact->hitimer, clockid, HRTIMER_MODE_ABS);
> +	gact->hitimer.function = gate_timer_func;
> +
> +	err = gate_get_start_time(gact, &start);
> +	if (err < 0) {
> +		NL_SET_ERR_MSG(extack,
> +			       "Internal error: failed get start time");
> +		goto release_mem;
> +	}
> +
> +	gact->current_close_time = start;
> +	gact->current_gate_status = GATE_ACT_GATE_OPEN | GATE_ACT_PENDING;
> +
> +	next = list_first_entry(&p->entries, struct tcfg_gate_entry, list);
> +	rcu_assign_pointer(gact->next_entry, next);
> +
> +	gate_start_timer(gact, start);
> +
> +	spin_lock_bh(&g->tcf_lock);
> +	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
> +	gact = rcu_replace_pointer(g->actg, gact,
> +				   lockdep_is_held(&g->tcf_lock));
> +	spin_unlock_bh(&g->tcf_lock);
> +
> +	if (goto_ch)
> +		tcf_chain_put_by_act(goto_ch);
> +	if (gact)
> +		kfree_rcu(gact, rcu);

This leaks entries. For example, tunnel key action implements
tunnel_key_release_params() helper that is used by both init and release
code. I guess that would be the best approach here as well.

> +
> +	if (ret == ACT_P_CREATED)
> +		tcf_idr_insert(tn, *a);
> +	return ret;
> +
> +release_mem:
> +	kfree(gact);
> +put_chain:
> +	if (goto_ch)
> +		tcf_chain_put_by_act(goto_ch);
> +release_idr:
> +	tcf_idr_release(*a, bind);
> +	return err;
> +}
> +
> +static void tcf_gate_cleanup(struct tc_action *a)
> +{
> +	struct tcf_gate *g = to_gate(a);
> +	struct tcfg_gate_entry *entry, *n;
> +	struct tcf_gate_params *p;
> +	struct gate_action *gact;
> +
> +	spin_lock_bh(&g->tcf_lock);
> +	gact = rcu_dereference_protected(g->actg,
> +					 lockdep_is_held(&g->tcf_lock));
> +	hrtimer_cancel(&gact->hitimer);
> +
> +	p = get_gate_param(gact);
> +	list_for_each_entry_safe(entry, n, &p->entries, list) {
> +		list_del(&entry->list);
> +		kfree(entry);
> +	}
> +	spin_unlock_bh(&g->tcf_lock);
> +
> +	kfree_rcu(gact, rcu);
> +}
> +
> +static int dumping_entry(struct sk_buff *skb,
> +			 struct tcfg_gate_entry *entry)
> +{
> +	struct nlattr *item;
> +
> +	item = nla_nest_start_noflag(skb, TCA_GATE_ONE_ENTRY);
> +	if (!item)
> +		return -ENOSPC;
> +
> +	if (nla_put_u32(skb, TCA_GATE_ENTRY_INDEX, entry->index))
> +		goto nla_put_failure;
> +
> +	if (entry->gate_state && nla_put_flag(skb, TCA_GATE_ENTRY_GATE))
> +		goto nla_put_failure;
> +
> +	if (nla_put_u32(skb, TCA_GATE_ENTRY_INTERVAL, entry->interval))
> +		goto nla_put_failure;
> +
> +	if (nla_put_s32(skb, TCA_GATE_ENTRY_MAX_OCTETS, entry->maxoctets))
> +		goto nla_put_failure;
> +
> +	if (nla_put_s32(skb, TCA_GATE_ENTRY_IPV, entry->ipv))
> +		goto nla_put_failure;
> +
> +	return nla_nest_end(skb, item);
> +
> +nla_put_failure:
> +	nla_nest_cancel(skb, item);
> +	return -1;
> +}
> +
> +static int tcf_gate_dump(struct sk_buff *skb, struct tc_action *a,
> +			 int bind, int ref)
> +{
> +	unsigned char *b = skb_tail_pointer(skb);
> +	struct tcf_gate *g = to_gate(a);
> +	struct tc_gate opt = {
> +		.index    = g->tcf_index,
> +		.refcnt   = refcount_read(&g->tcf_refcnt) - ref,
> +		.bindcnt  = atomic_read(&g->tcf_bindcnt) - bind,
> +	};
> +	struct tcfg_gate_entry *entry;
> +	struct gate_action *gact;
> +	struct tcf_gate_params *p;
> +	struct nlattr *entry_list;
> +	struct tcf_t t;
> +
> +	spin_lock_bh(&g->tcf_lock);
> +	opt.action = g->tcf_action;
> +	gact = rcu_dereference_protected(g->actg,
> +					 lockdep_is_held(&g->tcf_lock));
> +
> +	p = get_gate_param(gact);
> +
> +	if (nla_put(skb, TCA_GATE_PARMS, sizeof(opt), &opt))
> +		goto nla_put_failure;
> +
> +	if (nla_put_u64_64bit(skb, TCA_GATE_BASE_TIME,
> +			      p->tcfg_basetime, TCA_GATE_PAD))
> +		goto nla_put_failure;
> +
> +	if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME,
> +			      p->tcfg_cycletime, TCA_GATE_PAD))
> +		goto nla_put_failure;
> +
> +	if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME_EXT,
> +			      p->tcfg_cycletime_ext, TCA_GATE_PAD))
> +		goto nla_put_failure;
> +
> +	if (nla_put_s32(skb, TCA_GATE_CLOCKID, p->tcfg_clockid))
> +		goto nla_put_failure;
> +
> +	if (nla_put_u32(skb, TCA_GATE_FLAGS, p->tcfg_flags))
> +		goto nla_put_failure;
> +
> +	if (nla_put_s32(skb, TCA_GATE_PRIORITY, p->tcfg_priority))
> +		goto nla_put_failure;
> +
> +	entry_list = nla_nest_start_noflag(skb, TCA_GATE_ENTRY_LIST);
> +	if (!entry_list)
> +		goto nla_put_failure;
> +
> +	list_for_each_entry(entry, &p->entries, list) {
> +		if (dumping_entry(skb, entry) < 0)
> +			goto nla_put_failure;
> +	}
> +
> +	nla_nest_end(skb, entry_list);
> +
> +	tcf_tm_dump(&t, &g->tcf_tm);
> +	if (nla_put_64bit(skb, TCA_GATE_TM, sizeof(t), &t, TCA_GATE_PAD))
> +		goto nla_put_failure;
> +	spin_unlock_bh(&g->tcf_lock);
> +
> +	return skb->len;
> +
> +nla_put_failure:
> +	spin_unlock_bh(&g->tcf_lock);
> +	nlmsg_trim(skb, b);
> +	return -1;
> +}
> +
> +static int tcf_gate_walker(struct net *net, struct sk_buff *skb,
> +			   struct netlink_callback *cb, int type,
> +			   const struct tc_action_ops *ops,
> +			   struct netlink_ext_ack *extack)
> +{
> +	struct tc_action_net *tn = net_generic(net, gate_net_id);
> +
> +	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
> +}
> +
> +static void tcf_gate_stats_update(struct tc_action *a, u64 bytes, u32 packets,
> +				  u64 lastuse, bool hw)
> +{
> +	struct tcf_gate *g = to_gate(a);
> +	struct tcf_t *tm = &g->tcf_tm;
> +
> +	tcf_action_update_stats(a, bytes, packets, false, hw);
> +	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
> +}
> +
> +static int tcf_gate_search(struct net *net, struct tc_action **a, u32 index)
> +{
> +	struct tc_action_net *tn = net_generic(net, gate_net_id);
> +
> +	return tcf_idr_search(tn, a, index);
> +}
> +
> +static size_t tcf_gate_get_fill_size(const struct tc_action *act)
> +{
> +	return nla_total_size(sizeof(struct tc_gate));
> +}
> +
> +static struct tc_action_ops act_gate_ops = {
> +	.kind		=	"gate",
> +	.id		=	TCA_ID_GATE,
> +	.owner		=	THIS_MODULE,
> +	.act		=	tcf_gate_act,
> +	.dump		=	tcf_gate_dump,
> +	.init		=	tcf_gate_init,
> +	.cleanup	=	tcf_gate_cleanup,
> +	.walk		=	tcf_gate_walker,
> +	.stats_update	=	tcf_gate_stats_update,
> +	.get_fill_size	=	tcf_gate_get_fill_size,
> +	.lookup		=	tcf_gate_search,
> +	.size		=	sizeof(struct gate_action),
> +};
> +
> +static __net_init int gate_init_net(struct net *net)
> +{
> +	struct tc_action_net *tn = net_generic(net, gate_net_id);
> +
> +	return tc_action_net_init(net, tn, &act_gate_ops);
> +}
> +
> +static void __net_exit gate_exit_net(struct list_head *net_list)
> +{
> +	tc_action_net_exit(net_list, gate_net_id);
> +}
> +
> +static struct pernet_operations gate_net_ops = {
> +	.init = gate_init_net,
> +	.exit_batch = gate_exit_net,
> +	.id   = &gate_net_id,
> +	.size = sizeof(struct tc_action_net),
> +};
> +
> +static int __init gate_init_module(void)
> +{
> +	return tcf_register_action(&act_gate_ops, &gate_net_ops);
> +}
> +
> +static void __exit gate_cleanup_module(void)
> +{
> +	tcf_unregister_action(&act_gate_ops, &gate_net_ops);
> +}
> +
> +module_init(gate_init_module);
> +module_exit(gate_cleanup_module);
> +MODULE_LICENSE("GPL v2");

Hi Po,

Nice to see even more work on the TSN standards in the upstream kernel.

On 22.04.2020 10:48, Po Liu wrote:
>EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
>Introduce a ingress frame gate control flow action.
>Tc gate action does the work like this:
>Assume there is a gate allow specified ingress frames can be passed at
>specific time slot, and be dropped at specific time slot. Tc filter
>chooses the ingress frames, and tc gate action would specify what slot
>does these frames can be passed to device and what time slot would be
>dropped.
>Tc gate action would provide an entry list to tell how much time gate
>keep open and how much time gate keep state close. Gate action also
>assign a start time to tell when the entry list start. Then driver would
>repeat the gate entry list cyclically.
>For the software simulation, gate action requires the user assign a time
>clock type.
>
>Below is the setting example in user space. Tc filter a stream source ip
>address is 192.168.0.20 and gate action own two time slots. One is last
>200ms gate open let frame pass another is last 100ms gate close let
>frames dropped. When the frames have passed total frames over 8000000
>bytes, frames will be dropped in one 200000000ns time slot.
>
>> tc qdisc add dev eth0 ingress
>
>> tc filter add dev eth0 parent ffff: protocol ip \
>           flower src_ip 192.168.0.20 \
>           action gate index 2 clockid CLOCK_TAI \
>           sched-entry open 200000000 -1 8000000 \
>           sched-entry close 100000000 -1 -1

First of all, it is a long time since I read the 802.1Qci and when I did
it, it was a draft. So please let me know if I'm completly off here.

I know you are focusing on the gate control in this patch serie, but I
assume that you later will want to do the policing and flow-meter as
well. And it could make sense to consider how all of this work
toghether.

A common use-case for the policing is to have multiple rules pointing at
the same policing instance. Maybe you want the sum of the traffic on 2
ports to be limited to 100mbit. If you specify such action on the
individual rule (like done with the gate), then you can not have two
rules pointing at the same policer instance.

Long storry short, have you considered if it would be better to do
something like:

   tc filter add dev eth0 parent ffff: protocol ip \
            flower src_ip 192.168.0.20 \
            action psfp-id 42

And then have some other function to configure the properties of psfp-id
42?


/Allan

Hi Allan,

On Wed, 22 Apr 2020 at 22:20, Allan W. Nielsen
<allan.nielsen@microchip.com> wrote:
>
> Hi Po,
>
> Nice to see even more work on the TSN standards in the upstream kernel.
>
> On 22.04.2020 10:48, Po Liu wrote:
> >EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> >
> >Introduce a ingress frame gate control flow action.
> >Tc gate action does the work like this:
> >Assume there is a gate allow specified ingress frames can be passed at
> >specific time slot, and be dropped at specific time slot. Tc filter
> >chooses the ingress frames, and tc gate action would specify what slot
> >does these frames can be passed to device and what time slot would be
> >dropped.
> >Tc gate action would provide an entry list to tell how much time gate
> >keep open and how much time gate keep state close. Gate action also
> >assign a start time to tell when the entry list start. Then driver would
> >repeat the gate entry list cyclically.
> >For the software simulation, gate action requires the user assign a time
> >clock type.
> >
> >Below is the setting example in user space. Tc filter a stream source ip
> >address is 192.168.0.20 and gate action own two time slots. One is last
> >200ms gate open let frame pass another is last 100ms gate close let
> >frames dropped. When the frames have passed total frames over 8000000
> >bytes, frames will be dropped in one 200000000ns time slot.
> >
> >> tc qdisc add dev eth0 ingress
> >
> >> tc filter add dev eth0 parent ffff: protocol ip \
> >           flower src_ip 192.168.0.20 \
> >           action gate index 2 clockid CLOCK_TAI \
> >           sched-entry open 200000000 -1 8000000 \
> >           sched-entry close 100000000 -1 -1
>
> First of all, it is a long time since I read the 802.1Qci and when I did
> it, it was a draft. So please let me know if I'm completly off here.
>
> I know you are focusing on the gate control in this patch serie, but I
> assume that you later will want to do the policing and flow-meter as
> well. And it could make sense to consider how all of this work
> toghether.
>
> A common use-case for the policing is to have multiple rules pointing at
> the same policing instance. Maybe you want the sum of the traffic on 2
> ports to be limited to 100mbit. If you specify such action on the
> individual rule (like done with the gate), then you can not have two
> rules pointing at the same policer instance.
>
> Long storry short, have you considered if it would be better to do
> something like:
>
>    tc filter add dev eth0 parent ffff: protocol ip \
>             flower src_ip 192.168.0.20 \
>             action psfp-id 42
>
> And then have some other function to configure the properties of psfp-id
> 42?
>
>
> /Allan
>

It is very good that you brought it up though, since in my opinion too
it is a rather important aspect, and it seems that the fact this
feature is already designed-in was a bit too subtle.

"psfp-id" is actually his "index" argument.

You can actually do this:
tc filter add dev eth0 ingress \
        flower skip_hw dst_mac 01:80:c2:00:00:0e \
        action gate index 1 clockid CLOCK_TAI \
        base-time 200000000000 \
        sched-entry OPEN 200000000 -1 -1 \
        sched-entry CLOSE 100000000 -1 -1
tc filter add dev eth0 ingress \
        flower skip_hw dst_mac 01:80:c2:00:00:0f \
        action gate index 1

Then 2 filters get created with the same action:

tc -s filter show dev swp2 ingress
filter protocol all pref 49151 flower chain 0
filter protocol all pref 49151 flower chain 0 handle 0x1
  dst_mac 01:80:c2:00:00:0f
  skip_hw
  not_in_hw
        action order 1:
        priority wildcard       clockid TAI     flags 0x6404f
        base-time 200000000000                  cycle-time 300000000
         cycle-time-ext 0
         number    0    gate-state open         interval 200000000
         ipv wildcard    max-octets wildcard
         number    1    gate-state close        interval 100000000
         ipv wildcard    max-octets wildcard
        pipe
         index 2 ref 2 bind 2 installed 168 sec used 168 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0

filter protocol all pref 49152 flower chain 0
filter protocol all pref 49152 flower chain 0 handle 0x1
  dst_mac 01:80:c2:00:00:0e
  skip_hw
  not_in_hw
        action order 1:
        priority wildcard       clockid TAI     flags 0x6404f
        base-time 200000000000                  cycle-time 300000000
         cycle-time-ext 0
         number    0    gate-state open         interval 200000000
         ipv wildcard    max-octets wildcard
         number    1    gate-state close        interval 100000000
         ipv wildcard    max-octets wildcard
        pipe
         index 2 ref 2 bind 2 installed 168 sec used 168 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0

Actually my only concern is that maybe this mechanism should (?) have
been more generic. At the moment, this patch series implements it via
a TCA_GATE_ENTRY_INDEX netlink attribute, so every action which wants
to be shared across filters needs to reinvent this wheel.

Thoughts, everyone?

Thanks,
-Vladimir

On Wed, Apr 22, 2020 at 12:31 PM Vladimir Oltean <olteanv@gmail.com> wrote:
>
> Hi Allan,
>
> On Wed, 22 Apr 2020 at 22:20, Allan W. Nielsen
> <allan.nielsen@microchip.com> wrote:
> >
> > Hi Po,
> >
> > Nice to see even more work on the TSN standards in the upstream kernel.
> >
> > On 22.04.2020 10:48, Po Liu wrote:
> > >EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> > >
> > >Introduce a ingress frame gate control flow action.
> > >Tc gate action does the work like this:
> > >Assume there is a gate allow specified ingress frames can be passed at
> > >specific time slot, and be dropped at specific time slot. Tc filter
> > >chooses the ingress frames, and tc gate action would specify what slot
> > >does these frames can be passed to device and what time slot would be
> > >dropped.
> > >Tc gate action would provide an entry list to tell how much time gate
> > >keep open and how much time gate keep state close. Gate action also
> > >assign a start time to tell when the entry list start. Then driver would
> > >repeat the gate entry list cyclically.
> > >For the software simulation, gate action requires the user assign a time
> > >clock type.
> > >
> > >Below is the setting example in user space. Tc filter a stream source ip
> > >address is 192.168.0.20 and gate action own two time slots. One is last
> > >200ms gate open let frame pass another is last 100ms gate close let
> > >frames dropped. When the frames have passed total frames over 8000000
> > >bytes, frames will be dropped in one 200000000ns time slot.
> > >
> > >> tc qdisc add dev eth0 ingress
> > >
> > >> tc filter add dev eth0 parent ffff: protocol ip \
> > >           flower src_ip 192.168.0.20 \
> > >           action gate index 2 clockid CLOCK_TAI \
> > >           sched-entry open 200000000 -1 8000000 \
> > >           sched-entry close 100000000 -1 -1
> >
> > First of all, it is a long time since I read the 802.1Qci and when I did
> > it, it was a draft. So please let me know if I'm completly off here.
> >
> > I know you are focusing on the gate control in this patch serie, but I
> > assume that you later will want to do the policing and flow-meter as
> > well. And it could make sense to consider how all of this work
> > toghether.
> >
> > A common use-case for the policing is to have multiple rules pointing at
> > the same policing instance. Maybe you want the sum of the traffic on 2
> > ports to be limited to 100mbit. If you specify such action on the
> > individual rule (like done with the gate), then you can not have two
> > rules pointing at the same policer instance.
> >
> > Long storry short, have you considered if it would be better to do
> > something like:
> >
> >    tc filter add dev eth0 parent ffff: protocol ip \
> >             flower src_ip 192.168.0.20 \
> >             action psfp-id 42
> >
> > And then have some other function to configure the properties of psfp-id
> > 42?
> >
> >
> > /Allan
> >
>
> It is very good that you brought it up though, since in my opinion too
> it is a rather important aspect, and it seems that the fact this
> feature is already designed-in was a bit too subtle.
>
> "psfp-id" is actually his "index" argument.
>
> You can actually do this:
> tc filter add dev eth0 ingress \
>         flower skip_hw dst_mac 01:80:c2:00:00:0e \
>         action gate index 1 clockid CLOCK_TAI \
>         base-time 200000000000 \
>         sched-entry OPEN 200000000 -1 -1 \
>         sched-entry CLOSE 100000000 -1 -1
> tc filter add dev eth0 ingress \
>         flower skip_hw dst_mac 01:80:c2:00:00:0f \
>         action gate index 1
>
> Then 2 filters get created with the same action:
>
> tc -s filter show dev swp2 ingress
> filter protocol all pref 49151 flower chain 0
> filter protocol all pref 49151 flower chain 0 handle 0x1
>   dst_mac 01:80:c2:00:00:0f
>   skip_hw
>   not_in_hw
>         action order 1:
>         priority wildcard       clockid TAI     flags 0x6404f
>         base-time 200000000000                  cycle-time 300000000
>          cycle-time-ext 0
>          number    0    gate-state open         interval 200000000
>          ipv wildcard    max-octets wildcard
>          number    1    gate-state close        interval 100000000
>          ipv wildcard    max-octets wildcard
>         pipe
>          index 2 ref 2 bind 2 installed 168 sec used 168 sec
>         Action statistics:
>         Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>         backlog 0b 0p requeues 0
>
> filter protocol all pref 49152 flower chain 0
> filter protocol all pref 49152 flower chain 0 handle 0x1
>   dst_mac 01:80:c2:00:00:0e
>   skip_hw
>   not_in_hw
>         action order 1:
>         priority wildcard       clockid TAI     flags 0x6404f
>         base-time 200000000000                  cycle-time 300000000
>          cycle-time-ext 0
>          number    0    gate-state open         interval 200000000
>          ipv wildcard    max-octets wildcard
>          number    1    gate-state close        interval 100000000
>          ipv wildcard    max-octets wildcard
>         pipe
>          index 2 ref 2 bind 2 installed 168 sec used 168 sec
>         Action statistics:
>         Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>         backlog 0b 0p requeues 0
>
> Actually my only concern is that maybe this mechanism should (?) have
> been more generic. At the moment, this patch series implements it via
> a TCA_GATE_ENTRY_INDEX netlink attribute, so every action which wants
> to be shared across filters needs to reinvent this wheel.
>
> Thoughts, everyone?

I don't have anything valuable to add, aside from commenting this
whole thing makes my brain hurt.

> Thanks,
> -Vladimir

Hi Vlad Buslov,

> -----Original Message-----
> From: Vlad Buslov <vlad@buslov.dev>
> Sent: 2020年4月22日 21:23
> To: Po Liu <po.liu@nxp.com>
> Cc: davem@davemloft.net; linux-kernel@vger.kernel.org;
> netdev@vger.kernel.org; vinicius.gomes@intel.com; Claudiu Manoil
> <claudiu.manoil@nxp.com>; Vladimir Oltean <vladimir.oltean@nxp.com>;
> Alexandru Marginean <alexandru.marginean@nxp.com>;
> michael.chan@broadcom.com; vishal@chelsio.com;
> saeedm@mellanox.com; leon@kernel.org; jiri@mellanox.com;
> idosch@mellanox.com; alexandre.belloni@bootlin.com;
> UNGLinuxDriver@microchip.com; kuba@kernel.org; jhs@mojatatu.com;
> xiyou.wangcong@gmail.com; simon.horman@netronome.com;
> pablo@netfilter.org; moshe@mellanox.com; m-karicheri2@ti.com;
> andre.guedes@linux.intel.com; stephen@networkplumber.org
> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow
> action
> 
> Caution: EXT Email
> 
> Hi Po,
> 
> On Wed 22 Apr 2020 at 05:48, Po Liu <Po.Liu@nxp.com> wrote:
> > Introduce a ingress frame gate control flow action.
> > Tc gate action does the work like this:
> > Assume there is a gate allow specified ingress frames can be passed at
> > specific time slot, and be dropped at specific time slot. Tc filter
> > chooses the ingress frames, and tc gate action would specify what slot
> > does these frames can be passed to device and what time slot would be
> > dropped.
> > Tc gate action would provide an entry list to tell how much time gate
> > keep open and how much time gate keep state close. Gate action also
> > assign a start time to tell when the entry list start. Then driver
> > would repeat the gate entry list cyclically.
> > For the software simulation, gate action requires the user assign a
> > time clock type.
> >
> > Below is the setting example in user space. Tc filter a stream source
> > ip address is 192.168.0.20 and gate action own two time slots. One is
> > last 200ms gate open let frame pass another is last 100ms gate close
> > let frames dropped. When the frames have passed total frames over
> > 8000000 bytes, frames will be dropped in one 200000000ns time slot.
> >
> >> tc qdisc add dev eth0 ingress
> >
> >> tc filter add dev eth0 parent ffff: protocol ip \
> >          flower src_ip 192.168.0.20 \
> >          action gate index 2 clockid CLOCK_TAI \
> >          sched-entry open 200000000 -1 8000000 \
> >          sched-entry close 100000000 -1 -1
> >
> >> tc chain del dev eth0 ingress chain 0
> >
> > "sched-entry" follow the name taprio style. Gate state is
> > "open"/"close". Follow with period nanosecond. Then next item is
> > internal priority value means which ingress queue should put. "-1"
> > means wildcard. The last value optional specifies the maximum number
> > of MSDU octets that are permitted to pass the gate during the
> > specified time interval.
> > Base-time is not set will be 0 as default, as result start time would
> > be ((N + 1) * cycletime) which is the minimal of future time.
> >
> > Below example shows filtering a stream with destination mac address is
> > 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The
> > gate action would run with one close time slot which means always keep
> close.
> > The time cycle is total 200000000ns. The base-time would calculate by:
> >
> >  1357000000000 + (N + 1) * cycletime
> >
> > When the total value is the future time, it will be the start time.
> > The cycletime here would be 200000000ns for this case.
> >
> >> tc filter add dev eth0 parent ffff:  protocol ip \
> >          flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
> >          action gate index 12 base-time 1357000000000 \
> >          sched-entry close 200000000 -1 -1 \
> >          clockid CLOCK_TAI
> >
> > Signed-off-by: Po Liu <Po.Liu@nxp.com>
> > ---
> >  include/net/tc_act/tc_gate.h        |  54 +++
> >  include/uapi/linux/pkt_cls.h        |   1 +
> >  include/uapi/linux/tc_act/tc_gate.h |  47 ++
> >  net/sched/Kconfig                   |  13 +
> >  net/sched/Makefile                  |   1 +
> >  net/sched/act_gate.c                | 647 ++++++++++++++++++++++++++++
> >  6 files changed, 763 insertions(+)
> >  create mode 100644 include/net/tc_act/tc_gate.h  create mode 100644
> > include/uapi/linux/tc_act/tc_gate.h
> >  create mode 100644 net/sched/act_gate.c
> >
> > diff --git a/include/net/tc_act/tc_gate.h
> > b/include/net/tc_act/tc_gate.h new file mode 100644 index
> > 000000000000..b0ace55b2aaa
> > --- /dev/null
> > +++ b/include/net/tc_act/tc_gate.h
> > @@ -0,0 +1,54 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > +/* Copyright 2020 NXP */
> > +
> > +#ifndef __NET_TC_GATE_H
> > +#define __NET_TC_GATE_H
> > +
> > +#include <net/act_api.h>
> > +#include <linux/tc_act/tc_gate.h>
> > +
> > +struct tcfg_gate_entry {
> > +     int                     index;
> > +     u8                      gate_state;
> > +     u32                     interval;
> > +     s32                     ipv;
> > +     s32                     maxoctets;
> > +     struct list_head        list;
> > +};
> > +
> > +struct tcf_gate_params {
> > +     s32                     tcfg_priority;
> > +     u64                     tcfg_basetime;
> > +     u64                     tcfg_cycletime;
> > +     u64                     tcfg_cycletime_ext;
> > +     u32                     tcfg_flags;
> > +     s32                     tcfg_clockid;
> > +     size_t                  num_entries;
> > +     struct list_head        entries;
> > +};
> > +
> > +#define GATE_ACT_GATE_OPEN   BIT(0)
> > +#define GATE_ACT_PENDING     BIT(1)
> > +struct gate_action {
> > +     struct tcf_gate_params param;
> > +     spinlock_t entry_lock;
> > +     u8 current_gate_status;
> > +     ktime_t current_close_time;
> > +     u32 current_entry_octets;
> > +     s32 current_max_octets;
> > +     struct tcfg_gate_entry __rcu *next_entry;
> > +     struct hrtimer hitimer;
> > +     enum tk_offsets tk_offset;
> > +     struct rcu_head rcu;
> > +};
> > +
> > +struct tcf_gate {
> > +     struct tc_action                common;
> > +     struct gate_action __rcu        *actg;
> > +};
> > +#define to_gate(a) ((struct tcf_gate *)a)
> > +
> > +#define get_gate_param(act) ((struct tcf_gate_params *)act) #define
> > +get_gate_action(p) ((struct gate_action *)p)
> > +
> > +#endif
> > diff --git a/include/uapi/linux/pkt_cls.h
> > b/include/uapi/linux/pkt_cls.h index 9f06d29cab70..fc672b232437
> 100644
> > --- a/include/uapi/linux/pkt_cls.h
> > +++ b/include/uapi/linux/pkt_cls.h
> > @@ -134,6 +134,7 @@ enum tca_id {
> >       TCA_ID_CTINFO,
> >       TCA_ID_MPLS,
> >       TCA_ID_CT,
> > +     TCA_ID_GATE,
> >       /* other actions go here */
> >       __TCA_ID_MAX = 255
> >  };
> > diff --git a/include/uapi/linux/tc_act/tc_gate.h
> > b/include/uapi/linux/tc_act/tc_gate.h
> > new file mode 100644
> > index 000000000000..f214b3a6d44f
> > --- /dev/null
> > +++ b/include/uapi/linux/tc_act/tc_gate.h
> > @@ -0,0 +1,47 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> > +/* Copyright 2020 NXP */
> > +
> > +#ifndef __LINUX_TC_GATE_H
> > +#define __LINUX_TC_GATE_H
> > +
> > +#include <linux/pkt_cls.h>
> > +
> > +struct tc_gate {
> > +     tc_gen;
> > +};
> > +
> > +enum {
> > +     TCA_GATE_ENTRY_UNSPEC,
> > +     TCA_GATE_ENTRY_INDEX,
> > +     TCA_GATE_ENTRY_GATE,
> > +     TCA_GATE_ENTRY_INTERVAL,
> > +     TCA_GATE_ENTRY_IPV,
> > +     TCA_GATE_ENTRY_MAX_OCTETS,
> > +     __TCA_GATE_ENTRY_MAX,
> > +};
> > +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
> > +
> > +enum {
> > +     TCA_GATE_ONE_ENTRY_UNSPEC,
> > +     TCA_GATE_ONE_ENTRY,
> > +     __TCA_GATE_ONE_ENTRY_MAX,
> > +};
> > +#define TCA_GATE_ONE_ENTRY_MAX (__TCA_GATE_ONE_ENTRY_MAX
> - 1)
> > +
> > +enum {
> > +     TCA_GATE_UNSPEC,
> > +     TCA_GATE_TM,
> > +     TCA_GATE_PARMS,
> > +     TCA_GATE_PAD,
> > +     TCA_GATE_PRIORITY,
> > +     TCA_GATE_ENTRY_LIST,
> > +     TCA_GATE_BASE_TIME,
> > +     TCA_GATE_CYCLE_TIME,
> > +     TCA_GATE_CYCLE_TIME_EXT,
> > +     TCA_GATE_FLAGS,
> > +     TCA_GATE_CLOCKID,
> > +     __TCA_GATE_MAX,
> > +};
> > +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
> > +
> > +#endif
> > diff --git a/net/sched/Kconfig b/net/sched/Kconfig index
> > bfbefb7bff9d..1314549c7567 100644
> > --- a/net/sched/Kconfig
> > +++ b/net/sched/Kconfig
> > @@ -981,6 +981,19 @@ config NET_ACT_CT
> >         To compile this code as a module, choose M here: the
> >         module will be called act_ct.
> >
> > +config NET_ACT_GATE
> > +     tristate "Frame gate entry list control tc action"
> > +     depends on NET_CLS_ACT
> > +     help
> > +       Say Y here to allow to control the ingress flow to be passed at
> > +       specific time slot and be dropped at other specific time slot by
> > +       the gate entry list. The manipulation will simulate the IEEE
> > +       802.1Qci stream gate control behavior.
> > +
> > +       If unsure, say N.
> > +       To compile this code as a module, choose M here: the
> > +       module will be called act_gate.
> > +
> >  config NET_IFE_SKBMARK
> >       tristate "Support to encoding decoding skb mark on IFE action"
> >       depends on NET_ACT_IFE
> > diff --git a/net/sched/Makefile b/net/sched/Makefile index
> > 31c367a6cd09..66bbf9a98f9e 100644
> > --- a/net/sched/Makefile
> > +++ b/net/sched/Makefile
> > @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)       +=
> act_meta_skbprio.o
> >  obj-$(CONFIG_NET_IFE_SKBTCINDEX)     += act_meta_skbtcindex.o
> >  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
> >  obj-$(CONFIG_NET_ACT_CT)     += act_ct.o
> > +obj-$(CONFIG_NET_ACT_GATE)   += act_gate.o
> >  obj-$(CONFIG_NET_SCH_FIFO)   += sch_fifo.o
> >  obj-$(CONFIG_NET_SCH_CBQ)    += sch_cbq.o
> >  obj-$(CONFIG_NET_SCH_HTB)    += sch_htb.o
> > diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c new file mode
> > 100644 index 000000000000..e932f402b4f1
> > --- /dev/null
> > +++ b/net/sched/act_gate.c
> > @@ -0,0 +1,647 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/* Copyright 2020 NXP */
> > +
> > +#include <linux/module.h>
> > +#include <linux/types.h>
> > +#include <linux/kernel.h>
> > +#include <linux/string.h>
> > +#include <linux/errno.h>
> > +#include <linux/skbuff.h>
> > +#include <linux/rtnetlink.h>
> > +#include <linux/init.h>
> > +#include <linux/slab.h>
> > +#include <net/act_api.h>
> > +#include <net/netlink.h>
> > +#include <net/pkt_cls.h>
> > +#include <net/tc_act/tc_gate.h>
> > +
> > +static unsigned int gate_net_id;
> > +static struct tc_action_ops act_gate_ops;
> > +
> > +static ktime_t gate_get_time(struct gate_action *gact) {
> > +     ktime_t mono = ktime_get();
> > +
> > +     switch (gact->tk_offset) {
> > +     case TK_OFFS_MAX:
> > +             return mono;
> > +     default:
> > +             return ktime_mono_to_any(mono, gact->tk_offset);
> > +     }
> > +
> > +     return KTIME_MAX;
> > +}
> > +
> > +static int gate_get_start_time(struct gate_action *gact, ktime_t
> > +*start) {
> > +     struct tcf_gate_params *param = get_gate_param(gact);
> > +     ktime_t now, base, cycle;
> > +     u64 n;
> > +
> > +     base = ns_to_ktime(param->tcfg_basetime);
> > +     now = gate_get_time(gact);
> > +
> > +     if (ktime_after(base, now)) {
> > +             *start = base;
> > +             return 0;
> > +     }
> > +
> > +     cycle = param->tcfg_cycletime;
> > +
> > +     /* cycle time should not be zero */
> > +     if (WARN_ON(!cycle))
> > +             return -EFAULT;
> 
> Looking at the init code it seems that this value can be set to 0 directly
> from netlink packet without further validation, which would allow user to
> trigger warning here.

Yes,  will avoid at ahead point.

> 
> > +
> > +     n = div64_u64(ktime_sub_ns(now, base), cycle);
> > +     *start = ktime_add_ns(base, (n + 1) * cycle);
> > +     return 0;
> > +}
> > +
> > +static void gate_start_timer(struct gate_action *gact, ktime_t start)
> > +{
> > +     ktime_t expires;
> > +
> > +     expires = hrtimer_get_expires(&gact->hitimer);
> > +     if (expires == 0)
> > +             expires = KTIME_MAX;
> > +
> > +     start = min_t(ktime_t, start, expires);
> > +
> > +     hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS); }
> > +
> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer) {
> > +     struct gate_action *gact = container_of(timer, struct gate_action,
> > +                                             hitimer);
> > +     struct tcf_gate_params *p = get_gate_param(gact);
> > +     struct tcfg_gate_entry *next;
> > +     ktime_t close_time, now;
> > +
> > +     spin_lock(&gact->entry_lock);
> > +
> > +     next = rcu_dereference_protected(gact->next_entry,
> > +
> > + lockdep_is_held(&gact->entry_lock));
> > +
> > +     /* cycle start, clear pending bit, clear total octets */
> > +     gact->current_gate_status = next->gate_state ?
> GATE_ACT_GATE_OPEN : 0;
> > +     gact->current_entry_octets = 0;
> > +     gact->current_max_octets = next->maxoctets;
> > +
> > +     gact->current_close_time = ktime_add_ns(gact->current_close_time,
> > +                                             next->interval);
> > +
> > +     close_time = gact->current_close_time;
> > +
> > +     if (list_is_last(&next->list, &p->entries))
> > +             next = list_first_entry(&p->entries,
> > +                                     struct tcfg_gate_entry, list);
> > +     else
> > +             next = list_next_entry(next, list);
> > +
> > +     now = gate_get_time(gact);
> > +
> > +     if (ktime_after(now, close_time)) {
> > +             ktime_t cycle, base;
> > +             u64 n;
> > +
> > +             cycle = p->tcfg_cycletime;
> > +             base = ns_to_ktime(p->tcfg_basetime);
> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
> > +     }
> > +
> > +     rcu_assign_pointer(gact->next_entry, next);
> > +     spin_unlock(&gact->entry_lock);
> 
> I have couple of question about synchronization here:
> 
> - Why do you need next_entry to be rcu pointer? It is only assigned here
> with entry_lock protection and in init code before action is visible to
> concurrent users. I don't see any unlocked rcu-protected readers here that
> could benefit from it.
> 
> - Why create dedicated entry_lock instead of using already existing per-
> action tcf_lock?

Will try to use the tcf_lock for verification.
The thoughts came from that the timer period arrived then check through the list and then update next time would take much more time.  Action function would be busy when traffic. So use a separate lock here for  

> 
> > +
> > +     hrtimer_set_expires(&gact->hitimer, close_time);
> > +
> > +     return HRTIMER_RESTART;
> > +}
> > +
> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
> > +                     struct tcf_result *res) {
> > +     struct tcf_gate *g = to_gate(a);
> > +     struct gate_action *gact;
> > +     int action;
> > +
> > +     tcf_lastuse_update(&g->tcf_tm);
> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
> > +
> > +     action = READ_ONCE(g->tcf_action);
> > +     rcu_read_lock();
> 
> Action fastpath is already rcu read lock protected, you don't need to
> manually obtain it.

Will be removed.

> 
> > +     gact = rcu_dereference_bh(g->actg);
> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {
> 
> Can't current_gate_status be concurrently modified by timer callback?
> This function doesn't use entry_lock to synchronize with timer.

Will try tcf_lock either.

> 
> > +             rcu_read_unlock();
> > +             return action;
> > +     }
> > +
> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
> 
> ...and here
> 
> > +             goto drop;
> > +
> > +     if (gact->current_max_octets >= 0) {
> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
> > +             if (gact->current_entry_octets >
> > + gact->current_max_octets) {
> 
> here also.
> 
> > +
> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
> 
> Please use tcf_action_inc_overlimit_qstats() and other wrappers for stats.
> Otherwise it will crash if user passes TCA_ACT_FLAGS_NO_PERCPU_STATS
> flag.

The tcf_action_inc_overlimit_qstats() can't show limit counts in tc show command. Is there anything need to do? 

> 
> > +                     goto drop;
> > +             }
> > +     }
> > +     rcu_read_unlock();
> > +
> > +     return action;
> > +drop:
> > +     rcu_read_unlock();
> > +     qstats_drop_inc(this_cpu_ptr(g->common.cpu_qstats));
> > +     return TC_ACT_SHOT;
> > +}
> > +
> > +static const struct nla_policy entry_policy[TCA_GATE_ENTRY_MAX + 1]
> = {
> > +     [TCA_GATE_ENTRY_INDEX]          = { .type = NLA_U32 },
> > +     [TCA_GATE_ENTRY_GATE]           = { .type = NLA_FLAG },
> > +     [TCA_GATE_ENTRY_INTERVAL]       = { .type = NLA_U32 },
> > +     [TCA_GATE_ENTRY_IPV]            = { .type = NLA_S32 },
> > +     [TCA_GATE_ENTRY_MAX_OCTETS]     = { .type = NLA_S32 },
> > +};
> > +
> > +static const struct nla_policy gate_policy[TCA_GATE_MAX + 1] = {
> > +     [TCA_GATE_PARMS]                = { .len = sizeof(struct tc_gate),
> > +                                         .type = NLA_EXACT_LEN },
> > +     [TCA_GATE_PRIORITY]             = { .type = NLA_S32 },
> > +     [TCA_GATE_ENTRY_LIST]           = { .type = NLA_NESTED },
> > +     [TCA_GATE_BASE_TIME]            = { .type = NLA_U64 },
> > +     [TCA_GATE_CYCLE_TIME]           = { .type = NLA_U64 },
> > +     [TCA_GATE_CYCLE_TIME_EXT]       = { .type = NLA_U64 },
> > +     [TCA_GATE_FLAGS]                = { .type = NLA_U32 },
> > +     [TCA_GATE_CLOCKID]              = { .type = NLA_S32 },
> > +};
> > +
> > +static int fill_gate_entry(struct nlattr **tb, struct tcfg_gate_entry *entry,
> > +                        struct netlink_ext_ack *extack) {
> > +     u32 interval = 0;
> > +
> > +     entry->gate_state = nla_get_flag(tb[TCA_GATE_ENTRY_GATE]);
> > +
> > +     if (tb[TCA_GATE_ENTRY_INTERVAL])
> > +             interval = nla_get_u32(tb[TCA_GATE_ENTRY_INTERVAL]);
> > +
> > +     if (interval == 0) {
> > +             NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
> > +             return -EINVAL;
> > +     }
> > +
> > +     entry->interval = interval;
> > +
> > +     if (tb[TCA_GATE_ENTRY_IPV])
> > +             entry->ipv = nla_get_s32(tb[TCA_GATE_ENTRY_IPV]);
> > +     else
> > +             entry->ipv = -1;
> > +
> > +     if (tb[TCA_GATE_ENTRY_MAX_OCTETS])
> > +             entry->maxoctets =
> nla_get_s32(tb[TCA_GATE_ENTRY_MAX_OCTETS]);
> > +     else
> > +             entry->maxoctets = -1;
> > +
> > +     return 0;
> > +}
> > +
> > +static int parse_gate_entry(struct nlattr *n, struct  tcfg_gate_entry
> *entry,
> > +                         int index, struct netlink_ext_ack *extack) {
> > +     struct nlattr *tb[TCA_GATE_ENTRY_MAX + 1] = { };
> > +     int err;
> 
> > +     err = nla_parse_nested(tb, TCA_GATE_ENTRY_MAX, n, entry_policy,
> extack);
> > +     if (err < 0) {
> > +             NL_SET_ERR_MSG(extack, "Could not parse nested entry");
> > +             return -EINVAL;
> > +     }
> > +
> > +     entry->index = index;
> > +
> > +     return fill_gate_entry(tb, entry, extack); }
> > +
> > +static int parse_gate_list(struct nlattr *list_attr,
> > +                        struct tcf_gate_params *sched,
> > +                        struct netlink_ext_ack *extack) {
> > +     struct tcfg_gate_entry *entry, *e;
> > +     struct nlattr *n;
> > +     int err, rem;
> > +     int i = 0;
> > +
> > +     if (!list_attr)
> > +             return -EINVAL;
> > +
> > +     nla_for_each_nested(n, list_attr, rem) {
> > +             if (nla_type(n) != TCA_GATE_ONE_ENTRY) {
> > +                     NL_SET_ERR_MSG(extack, "Attribute isn't type 'entry'");
> > +                     continue;
> > +             }
> > +
> > +             entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> > +             if (!entry) {
> > +                     NL_SET_ERR_MSG(extack, "Not enough memory for entry");
> > +                     err = -ENOMEM;
> > +                     goto release_list;
> > +             }
> > +
> > +             err = parse_gate_entry(n, entry, i, extack);
> > +             if (err < 0) {
> > +                     kfree(entry);
> > +                     goto release_list;
> > +             }
> > +
> > +             list_add_tail(&entry->list, &sched->entries);
> > +             i++;
> > +     }
> > +
> > +     sched->num_entries = i;
> > +
> > +     return i;
> > +
> > +release_list:
> > +     list_for_each_entry_safe(entry, e, &sched->entries, list) {
> > +             list_del(&entry->list);
> > +             kfree(entry);
> > +     }
> > +
> > +     return err;
> > +}
> > +
> > +static int tcf_gate_init(struct net *net, struct nlattr *nla,
> > +                      struct nlattr *est, struct tc_action **a,
> > +                      int ovr, int bind, bool rtnl_held,
> > +                      struct tcf_proto *tp, u32 flags,
> > +                      struct netlink_ext_ack *extack) {
> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
> > +     enum tk_offsets tk_offset = TK_OFFS_TAI;
> > +     struct nlattr *tb[TCA_GATE_MAX + 1];
> > +     struct tcf_chain *goto_ch = NULL;
> > +     struct tcfg_gate_entry *next;
> > +     struct tcf_gate_params *p;
> > +     struct gate_action *gact;
> > +     s32 clockid = CLOCK_TAI;
> > +     struct tc_gate *parm;
> > +     struct tcf_gate *g;
> > +     int ret = 0, err;
> > +     u64 basetime = 0;
> > +     u32 gflags = 0;
> > +     s32 prio = -1;
> > +     ktime_t start;
> > +     u32 index;
> > +
> > +     if (!nla)
> > +             return -EINVAL;
> > +
> > +     err = nla_parse_nested(tb, TCA_GATE_MAX, nla, gate_policy, extack);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     if (!tb[TCA_GATE_PARMS])
> > +             return -EINVAL;
> > +     parm = nla_data(tb[TCA_GATE_PARMS]);
> > +     index = parm->index;
> > +     err = tcf_idr_check_alloc(tn, &index, a, bind);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     if (err && bind)
> > +             return 0;
> > +
> > +     if (!err) {
> > +             ret = tcf_idr_create_from_flags(tn, index, est, a,
> > +                                             &act_gate_ops, bind, flags);
> > +             if (ret) {
> > +                     tcf_idr_cleanup(tn, index);
> > +                     return ret;
> > +             }
> > +
> > +             ret = ACT_P_CREATED;
> > +     } else if (!ovr) {
> > +             tcf_idr_release(*a, bind);
> > +             return -EEXIST;
> > +     }
> > +
> > +     if (tb[TCA_GATE_PRIORITY])
> > +             prio = nla_get_s32(tb[TCA_GATE_PRIORITY]);
> > +
> > +     if (tb[TCA_GATE_BASE_TIME])
> > +             basetime = nla_get_u64(tb[TCA_GATE_BASE_TIME]);
> > +
> > +     if (tb[TCA_GATE_FLAGS])
> > +             gflags = nla_get_u32(tb[TCA_GATE_FLAGS]);
> > +
> > +     if (tb[TCA_GATE_CLOCKID]) {
> > +             clockid = nla_get_s32(tb[TCA_GATE_CLOCKID]);
> > +             switch (clockid) {
> > +             case CLOCK_REALTIME:
> > +                     tk_offset = TK_OFFS_REAL;
> > +                     break;
> > +             case CLOCK_MONOTONIC:
> > +                     tk_offset = TK_OFFS_MAX;
> > +                     break;
> > +             case CLOCK_BOOTTIME:
> > +                     tk_offset = TK_OFFS_BOOT;
> > +                     break;
> > +             case CLOCK_TAI:
> > +                     tk_offset = TK_OFFS_TAI;
> > +                     break;
> > +             default:
> > +                     NL_SET_ERR_MSG(extack, "Invalid 'clockid'");
> > +                     goto release_idr;
> > +             }
> > +     }
> > +
> > +     err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
> > +     if (err < 0)
> > +             goto release_idr;
> > +
> > +     g = to_gate(*a);
> > +
> > +     gact = kzalloc(sizeof(*gact), GFP_KERNEL);
> > +     if (!gact) {
> > +             err = -ENOMEM;
> > +             goto put_chain;
> > +     }
> > +
> > +     p = get_gate_param(gact);
> > +
> > +     INIT_LIST_HEAD(&p->entries);
> > +     if (tb[TCA_GATE_ENTRY_LIST]) {
> > +             err = parse_gate_list(tb[TCA_GATE_ENTRY_LIST], p, extack);
> > +             if (err < 0)
> > +                     goto release_mem;
> > +     }
> > +
> > +     if (tb[TCA_GATE_CYCLE_TIME]) {
> > +             p->tcfg_cycletime = nla_get_u64(tb[TCA_GATE_CYCLE_TIME]);
> > +     } else {
> > +             struct tcfg_gate_entry *entry;
> > +             ktime_t cycle = 0;
> > +
> > +             list_for_each_entry(entry, &p->entries, list)
> > +                     cycle = ktime_add_ns(cycle, entry->interval);
> > +             p->tcfg_cycletime = cycle;
> > +     }
> > +
> > +     if (tb[TCA_GATE_CYCLE_TIME_EXT])
> > +             p->tcfg_cycletime_ext =
> > +                     nla_get_u64(tb[TCA_GATE_CYCLE_TIME_EXT]);
> > +
> > +     p->tcfg_priority = prio;
> > +     p->tcfg_basetime = basetime;
> > +     p->tcfg_clockid = clockid;
> > +     p->tcfg_flags = gflags;
> > +
> > +     gact->tk_offset = tk_offset;
> > +     spin_lock_init(&gact->entry_lock);
> > +     hrtimer_init(&gact->hitimer, clockid, HRTIMER_MODE_ABS);
> > +     gact->hitimer.function = gate_timer_func;
> > +
> > +     err = gate_get_start_time(gact, &start);
> > +     if (err < 0) {
> > +             NL_SET_ERR_MSG(extack,
> > +                            "Internal error: failed get start time");
> > +             goto release_mem;
> > +     }
> > +
> > +     gact->current_close_time = start;
> > +     gact->current_gate_status = GATE_ACT_GATE_OPEN |
> > + GATE_ACT_PENDING;
> > +
> > +     next = list_first_entry(&p->entries, struct tcfg_gate_entry, list);
> > +     rcu_assign_pointer(gact->next_entry, next);
> > +
> > +     gate_start_timer(gact, start);
> > +
> > +     spin_lock_bh(&g->tcf_lock);
> > +     goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
> > +     gact = rcu_replace_pointer(g->actg, gact,
> > +                                lockdep_is_held(&g->tcf_lock));
> > +     spin_unlock_bh(&g->tcf_lock);
> > +
> > +     if (goto_ch)
> > +             tcf_chain_put_by_act(goto_ch);
> > +     if (gact)
> > +             kfree_rcu(gact, rcu);
> 
> This leaks entries. For example, tunnel key action implements
> tunnel_key_release_params() helper that is used by both init and release
> code. I guess that would be the best approach here as well.
> 

Will refer the tunnel action. Thanks for pointing out.

> > +
> > +     if (ret == ACT_P_CREATED)
> > +             tcf_idr_insert(tn, *a);
> > +     return ret;
> > +
> > +release_mem:
> > +     kfree(gact);
> > +put_chain:
> > +     if (goto_ch)
> > +             tcf_chain_put_by_act(goto_ch);
> > +release_idr:
> > +     tcf_idr_release(*a, bind);
> > +     return err;
> > +}
> > +
> > +static void tcf_gate_cleanup(struct tc_action *a) {
> > +     struct tcf_gate *g = to_gate(a);
> > +     struct tcfg_gate_entry *entry, *n;
> > +     struct tcf_gate_params *p;
> > +     struct gate_action *gact;
> > +
> > +     spin_lock_bh(&g->tcf_lock);
> > +     gact = rcu_dereference_protected(g->actg,
> > +                                      lockdep_is_held(&g->tcf_lock));
> > +     hrtimer_cancel(&gact->hitimer);
> > +
> > +     p = get_gate_param(gact);
> > +     list_for_each_entry_safe(entry, n, &p->entries, list) {
> > +             list_del(&entry->list);
> > +             kfree(entry);
> > +     }
> > +     spin_unlock_bh(&g->tcf_lock);
> > +
> > +     kfree_rcu(gact, rcu);
> > +}
> > +
> > +static int dumping_entry(struct sk_buff *skb,
> > +                      struct tcfg_gate_entry *entry) {
> > +     struct nlattr *item;
> > +
> > +     item = nla_nest_start_noflag(skb, TCA_GATE_ONE_ENTRY);
> > +     if (!item)
> > +             return -ENOSPC;
> > +
> > +     if (nla_put_u32(skb, TCA_GATE_ENTRY_INDEX, entry->index))
> > +             goto nla_put_failure;
> > +
> > +     if (entry->gate_state && nla_put_flag(skb, TCA_GATE_ENTRY_GATE))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_u32(skb, TCA_GATE_ENTRY_INTERVAL, entry->interval))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_s32(skb, TCA_GATE_ENTRY_MAX_OCTETS, entry-
> >maxoctets))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_s32(skb, TCA_GATE_ENTRY_IPV, entry->ipv))
> > +             goto nla_put_failure;
> > +
> > +     return nla_nest_end(skb, item);
> > +
> > +nla_put_failure:
> > +     nla_nest_cancel(skb, item);
> > +     return -1;
> > +}
> > +
> > +static int tcf_gate_dump(struct sk_buff *skb, struct tc_action *a,
> > +                      int bind, int ref) {
> > +     unsigned char *b = skb_tail_pointer(skb);
> > +     struct tcf_gate *g = to_gate(a);
> > +     struct tc_gate opt = {
> > +             .index    = g->tcf_index,
> > +             .refcnt   = refcount_read(&g->tcf_refcnt) - ref,
> > +             .bindcnt  = atomic_read(&g->tcf_bindcnt) - bind,
> > +     };
> > +     struct tcfg_gate_entry *entry;
> > +     struct gate_action *gact;
> > +     struct tcf_gate_params *p;
> > +     struct nlattr *entry_list;
> > +     struct tcf_t t;
> > +
> > +     spin_lock_bh(&g->tcf_lock);
> > +     opt.action = g->tcf_action;
> > +     gact = rcu_dereference_protected(g->actg,
> > +                                      lockdep_is_held(&g->tcf_lock));
> > +
> > +     p = get_gate_param(gact);
> > +
> > +     if (nla_put(skb, TCA_GATE_PARMS, sizeof(opt), &opt))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_u64_64bit(skb, TCA_GATE_BASE_TIME,
> > +                           p->tcfg_basetime, TCA_GATE_PAD))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME,
> > +                           p->tcfg_cycletime, TCA_GATE_PAD))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME_EXT,
> > +                           p->tcfg_cycletime_ext, TCA_GATE_PAD))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_s32(skb, TCA_GATE_CLOCKID, p->tcfg_clockid))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_u32(skb, TCA_GATE_FLAGS, p->tcfg_flags))
> > +             goto nla_put_failure;
> > +
> > +     if (nla_put_s32(skb, TCA_GATE_PRIORITY, p->tcfg_priority))
> > +             goto nla_put_failure;
> > +
> > +     entry_list = nla_nest_start_noflag(skb, TCA_GATE_ENTRY_LIST);
> > +     if (!entry_list)
> > +             goto nla_put_failure;
> > +
> > +     list_for_each_entry(entry, &p->entries, list) {
> > +             if (dumping_entry(skb, entry) < 0)
> > +                     goto nla_put_failure;
> > +     }
> > +
> > +     nla_nest_end(skb, entry_list);
> > +
> > +     tcf_tm_dump(&t, &g->tcf_tm);
> > +     if (nla_put_64bit(skb, TCA_GATE_TM, sizeof(t), &t, TCA_GATE_PAD))
> > +             goto nla_put_failure;
> > +     spin_unlock_bh(&g->tcf_lock);
> > +
> > +     return skb->len;
> > +
> > +nla_put_failure:
> > +     spin_unlock_bh(&g->tcf_lock);
> > +     nlmsg_trim(skb, b);
> > +     return -1;
> > +}
> > +
> > +static int tcf_gate_walker(struct net *net, struct sk_buff *skb,
> > +                        struct netlink_callback *cb, int type,
> > +                        const struct tc_action_ops *ops,
> > +                        struct netlink_ext_ack *extack) {
> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
> > +
> > +     return tcf_generic_walker(tn, skb, cb, type, ops, extack); }
> > +
> > +static void tcf_gate_stats_update(struct tc_action *a, u64 bytes, u32
> packets,
> > +                               u64 lastuse, bool hw) {
> > +     struct tcf_gate *g = to_gate(a);
> > +     struct tcf_t *tm = &g->tcf_tm;
> > +
> > +     tcf_action_update_stats(a, bytes, packets, false, hw);
> > +     tm->lastuse = max_t(u64, tm->lastuse, lastuse); }
> > +
> > +static int tcf_gate_search(struct net *net, struct tc_action **a, u32
> > +index) {
> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
> > +
> > +     return tcf_idr_search(tn, a, index); }
> > +
> > +static size_t tcf_gate_get_fill_size(const struct tc_action *act) {
> > +     return nla_total_size(sizeof(struct tc_gate)); }
> > +
> > +static struct tc_action_ops act_gate_ops = {
> > +     .kind           =       "gate",
> > +     .id             =       TCA_ID_GATE,
> > +     .owner          =       THIS_MODULE,
> > +     .act            =       tcf_gate_act,
> > +     .dump           =       tcf_gate_dump,
> > +     .init           =       tcf_gate_init,
> > +     .cleanup        =       tcf_gate_cleanup,
> > +     .walk           =       tcf_gate_walker,
> > +     .stats_update   =       tcf_gate_stats_update,
> > +     .get_fill_size  =       tcf_gate_get_fill_size,
> > +     .lookup         =       tcf_gate_search,
> > +     .size           =       sizeof(struct gate_action),
> > +};
> > +
> > +static __net_init int gate_init_net(struct net *net) {
> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
> > +
> > +     return tc_action_net_init(net, tn, &act_gate_ops); }
> > +
> > +static void __net_exit gate_exit_net(struct list_head *net_list) {
> > +     tc_action_net_exit(net_list, gate_net_id); }
> > +
> > +static struct pernet_operations gate_net_ops = {
> > +     .init = gate_init_net,
> > +     .exit_batch = gate_exit_net,
> > +     .id   = &gate_net_id,
> > +     .size = sizeof(struct tc_action_net), };
> > +
> > +static int __init gate_init_module(void) {
> > +     return tcf_register_action(&act_gate_ops, &gate_net_ops); }
> > +
> > +static void __exit gate_cleanup_module(void) {
> > +     tcf_unregister_action(&act_gate_ops, &gate_net_ops); }
> > +
> > +module_init(gate_init_module);
> > +module_exit(gate_cleanup_module);
> > +MODULE_LICENSE("GPL v2");

Thanks a lot.

Br,
Po Liu

Hi Nielsen,

> -----Original Message-----
> From: Allan W. Nielsen <allan.nielsen@microchip.com>
> Sent: 2020年4月23日 3:19
> To: Po Liu <po.liu@nxp.com>
> Cc: davem@davemloft.net; linux-kernel@vger.kernel.org;
> netdev@vger.kernel.org; vinicius.gomes@intel.com; Claudiu Manoil
> <claudiu.manoil@nxp.com>; Vladimir Oltean <vladimir.oltean@nxp.com>;
> Alexandru Marginean <alexandru.marginean@nxp.com>;
> michael.chan@broadcom.com; vishal@chelsio.com;
> saeedm@mellanox.com; leon@kernel.org; jiri@mellanox.com;
> idosch@mellanox.com; alexandre.belloni@bootlin.com;
> UNGLinuxDriver@microchip.com; kuba@kernel.org; jhs@mojatatu.com;
> xiyou.wangcong@gmail.com; simon.horman@netronome.com;
> pablo@netfilter.org; moshe@mellanox.com; m-karicheri2@ti.com;
> andre.guedes@linux.intel.com; stephen@networkplumber.org
> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow
> action
> 
> Caution: EXT Email
> 
> Hi Po,
> 
> Nice to see even more work on the TSN standards in the upstream kernel.
> 
> On 22.04.2020 10:48, Po Liu wrote:
> >EXTERNAL EMAIL: Do not click links or open attachments unless you know
> >the content is safe
> >
> >Introduce a ingress frame gate control flow action.
> >Tc gate action does the work like this:
> >Assume there is a gate allow specified ingress frames can be passed at
> >specific time slot, and be dropped at specific time slot. Tc filter
> >chooses the ingress frames, and tc gate action would specify what slot
> >does these frames can be passed to device and what time slot would be
> >dropped.
> >Tc gate action would provide an entry list to tell how much time gate
> >keep open and how much time gate keep state close. Gate action also
> >assign a start time to tell when the entry list start. Then driver
> >would repeat the gate entry list cyclically.
> >For the software simulation, gate action requires the user assign a
> >time clock type.
> >
> >Below is the setting example in user space. Tc filter a stream source
> >ip address is 192.168.0.20 and gate action own two time slots. One is
> >last 200ms gate open let frame pass another is last 100ms gate close
> >let frames dropped. When the frames have passed total frames over
> >8000000 bytes, frames will be dropped in one 200000000ns time slot.
> >
> >> tc qdisc add dev eth0 ingress
> >
> >> tc filter add dev eth0 parent ffff: protocol ip \
> >           flower src_ip 192.168.0.20 \
> >           action gate index 2 clockid CLOCK_TAI \
> >           sched-entry open 200000000 -1 8000000 \
> >           sched-entry close 100000000 -1 -1
> 
> First of all, it is a long time since I read the 802.1Qci and when I did it, it
> was a draft. So please let me know if I'm completly off here.
> 
> I know you are focusing on the gate control in this patch serie, but I
> assume that you later will want to do the policing and flow-meter as well.
> And it could make sense to consider how all of this work toghether.

The gate action is the must have feature, so here is the part of it. And provide the stream filter implementation part in the driver.
I provided a whole thoughts, with flow-meter apply to policing action and other throughs in the RFC version. You can look back to that version for reference.

> 
> A common use-case for the policing is to have multiple rules pointing at
> the same policing instance. Maybe you want the sum of the traffic on 2
> ports to be limited to 100mbit. If you specify such action on the individual
> rule (like done with the gate), then you can not have two rules pointing at
> the same policer instance.
> 
> Long storry short, have you considered if it would be better to do
> something like:
> 
>    tc filter add dev eth0 parent ffff: protocol ip \
>             flower src_ip 192.168.0.20 \
>             action psfp-id 42
> 
> And then have some other function to configure the properties of psfp-id
> 42?

I think the psfp-id you mention is for the gate and stream filter and flow meter and stream-identify. For each they should have an index.
The stream-identify index come from the chain value. Gate index comes from the index in the gate action, two ports or more can share one same index gate index. Will same for the flow-meter action.

> 
> 
> /Allan

Thanks!

Br,
Po Liu

Hi Dave That,


> -----Original Message-----
> From: Dave Taht <dave.taht@gmail.com>
> Sent: 2020年4月23日 4:06
> To: Vladimir Oltean <olteanv@gmail.com>
> Cc: Allan W. Nielsen <allan.nielsen@microchip.com>; Po Liu
> <po.liu@nxp.com>; David S. Miller <davem@davemloft.net>; lkml <linux-
> kernel@vger.kernel.org>; netdev <netdev@vger.kernel.org>; Vinicius Costa
> Gomes <vinicius.gomes@intel.com>; Claudiu Manoil
> <claudiu.manoil@nxp.com>; Vladimir Oltean <vladimir.oltean@nxp.com>;
> Alexandru Marginean <alexandru.marginean@nxp.com>;
> michael.chan@broadcom.com; vishal@chelsio.com; Saeed Mahameed
> <saeedm@mellanox.com>; leon@kernel.org; Jiri Pirko
> <jiri@mellanox.com>; Ido Schimmel <idosch@mellanox.com>; Alexandre
> Belloni <alexandre.belloni@bootlin.com>; Microchip Linux Driver Support
> <UNGLinuxDriver@microchip.com>; Jakub Kicinski <kuba@kernel.org>;
> Jamal Hadi Salim <jhs@mojatatu.com>; Cong Wang
> <xiyou.wangcong@gmail.com>; simon.horman@netronome.com; Pablo
> Neira Ayuso <pablo@netfilter.org>; moshe@mellanox.com; Murali
> Karicheri <m-karicheri2@ti.com>; Andre Guedes
> <andre.guedes@linux.intel.com>; Stephen Hemminger
> <stephen@networkplumber.org>
> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow
> action
> 
> Caution: EXT Email
> 
> On Wed, Apr 22, 2020 at 12:31 PM Vladimir Oltean <olteanv@gmail.com>
> wrote:
> >
> > Hi Allan,
> >
> > On Wed, 22 Apr 2020 at 22:20, Allan W. Nielsen
> > <allan.nielsen@microchip.com> wrote:
> > >
> > > Hi Po,
> > >
> > > Nice to see even more work on the TSN standards in the upstream
> kernel.
> > >
> > > On 22.04.2020 10:48, Po Liu wrote:
> > > >EXTERNAL EMAIL: Do not click links or open attachments unless you
> > > >know the content is safe
> > > >
> > > >Introduce a ingress frame gate control flow action.
> > > >Tc gate action does the work like this:
> > > >Assume there is a gate allow specified ingress frames can be passed
> > > >at specific time slot, and be dropped at specific time slot. Tc
> > > >filter chooses the ingress frames, and tc gate action would specify
> > > >what slot does these frames can be passed to device and what time
> > > >slot would be dropped.
> > > >Tc gate action would provide an entry list to tell how much time
> > > >gate keep open and how much time gate keep state close. Gate
> action
> > > >also assign a start time to tell when the entry list start. Then
> > > >driver would repeat the gate entry list cyclically.
> > > >For the software simulation, gate action requires the user assign a
> > > >time clock type.
> > > >
> > > >Below is the setting example in user space. Tc filter a stream
> > > >source ip address is 192.168.0.20 and gate action own two time
> > > >slots. One is last 200ms gate open let frame pass another is last
> > > >100ms gate close let frames dropped. When the frames have passed
> > > >total frames over 8000000 bytes, frames will be dropped in one
> 200000000ns time slot.
> > > >
> > > >> tc qdisc add dev eth0 ingress
> > > >
> > > >> tc filter add dev eth0 parent ffff: protocol ip \
> > > >           flower src_ip 192.168.0.20 \
> > > >           action gate index 2 clockid CLOCK_TAI \
> > > >           sched-entry open 200000000 -1 8000000 \
> > > >           sched-entry close 100000000 -1 -1
> > >
> > > First of all, it is a long time since I read the 802.1Qci and when I
> > > did it, it was a draft. So please let me know if I'm completly off here.
> > >
> > > I know you are focusing on the gate control in this patch serie, but
> > > I assume that you later will want to do the policing and flow-meter
> > > as well. And it could make sense to consider how all of this work
> > > toghether.
> > >
> > > A common use-case for the policing is to have multiple rules
> > > pointing at the same policing instance. Maybe you want the sum of
> > > the traffic on 2 ports to be limited to 100mbit. If you specify such
> > > action on the individual rule (like done with the gate), then you
> > > can not have two rules pointing at the same policer instance.
> > >
> > > Long storry short, have you considered if it would be better to do
> > > something like:
> > >
> > >    tc filter add dev eth0 parent ffff: protocol ip \
> > >             flower src_ip 192.168.0.20 \
> > >             action psfp-id 42
> > >
> > > And then have some other function to configure the properties of
> > > psfp-id 42?
> > >
> > >
> > > /Allan
> > >
> >
> > It is very good that you brought it up though, since in my opinion too
> > it is a rather important aspect, and it seems that the fact this
> > feature is already designed-in was a bit too subtle.
> >
> > "psfp-id" is actually his "index" argument.
> >
> > You can actually do this:
> > tc filter add dev eth0 ingress \
> >         flower skip_hw dst_mac 01:80:c2:00:00:0e \
> >         action gate index 1 clockid CLOCK_TAI \
> >         base-time 200000000000 \
> >         sched-entry OPEN 200000000 -1 -1 \
> >         sched-entry CLOSE 100000000 -1 -1 tc filter add dev eth0
> > ingress \
> >         flower skip_hw dst_mac 01:80:c2:00:00:0f \
> >         action gate index 1
> >
> > Then 2 filters get created with the same action:
> >
> > tc -s filter show dev swp2 ingress
> > filter protocol all pref 49151 flower chain 0 filter protocol all pref
> > 49151 flower chain 0 handle 0x1
> >   dst_mac 01:80:c2:00:00:0f
> >   skip_hw
> >   not_in_hw
> >         action order 1:
> >         priority wildcard       clockid TAI     flags 0x6404f
> >         base-time 200000000000                  cycle-time 300000000
> >          cycle-time-ext 0
> >          number    0    gate-state open         interval 200000000
> >          ipv wildcard    max-octets wildcard
> >          number    1    gate-state close        interval 100000000
> >          ipv wildcard    max-octets wildcard
> >         pipe
> >          index 2 ref 2 bind 2 installed 168 sec used 168 sec
> >         Action statistics:
> >         Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
> >         backlog 0b 0p requeues 0
> >
> > filter protocol all pref 49152 flower chain 0 filter protocol all pref
> > 49152 flower chain 0 handle 0x1
> >   dst_mac 01:80:c2:00:00:0e
> >   skip_hw
> >   not_in_hw
> >         action order 1:
> >         priority wildcard       clockid TAI     flags 0x6404f
> >         base-time 200000000000                  cycle-time 300000000
> >          cycle-time-ext 0
> >          number    0    gate-state open         interval 200000000
> >          ipv wildcard    max-octets wildcard
> >          number    1    gate-state close        interval 100000000
> >          ipv wildcard    max-octets wildcard
> >         pipe
> >          index 2 ref 2 bind 2 installed 168 sec used 168 sec
> >         Action statistics:
> >         Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
> >         backlog 0b 0p requeues 0
> >
> > Actually my only concern is that maybe this mechanism should (?) have
> > been more generic. At the moment, this patch series implements it via
> > a TCA_GATE_ENTRY_INDEX netlink attribute, so every action which
> wants
> > to be shared across filters needs to reinvent this wheel.
> >
> > Thoughts, everyone?
> 
> I don't have anything valuable to add, aside from commenting this whole
> thing makes my brain hurt.

Thanks for express your thoughts.

> 
> > Thanks,
> > -Vladimir
> 
> 
> 
> --
> Make Music, Not War

Thanks!

> 
> Dave Täht
> CTO, TekLibre, LLC
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww
> .teklibre.com%2F&amp;data=02%7C01%7CPo.Liu%40nxp.com%7C09cf63bb
> 73ee4fb2e08108d7e6f8929f%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0
> %7C0%7C637231827599217479&amp;sdata=u3ILmBlK6RsVYDLy9gtFythp%2
> FbG2%2Bw40xea2N1sJvr4%3D&amp;reserved=0
> Tel: 1-831-435-0729



Br,
Po Liu

On Thu 23 Apr 2020 at 06:14, Po Liu <po.liu@nxp.com> wrote:
> Hi Vlad Buslov,
>
>> -----Original Message-----
>> From: Vlad Buslov <vlad@buslov.dev>
>> Sent: 2020年4月22日 21:23
>> To: Po Liu <po.liu@nxp.com>
>> Cc: davem@davemloft.net; linux-kernel@vger.kernel.org;
>> netdev@vger.kernel.org; vinicius.gomes@intel.com; Claudiu Manoil
>> <claudiu.manoil@nxp.com>; Vladimir Oltean <vladimir.oltean@nxp.com>;
>> Alexandru Marginean <alexandru.marginean@nxp.com>;
>> michael.chan@broadcom.com; vishal@chelsio.com;
>> saeedm@mellanox.com; leon@kernel.org; jiri@mellanox.com;
>> idosch@mellanox.com; alexandre.belloni@bootlin.com;
>> UNGLinuxDriver@microchip.com; kuba@kernel.org; jhs@mojatatu.com;
>> xiyou.wangcong@gmail.com; simon.horman@netronome.com;
>> pablo@netfilter.org; moshe@mellanox.com; m-karicheri2@ti.com;
>> andre.guedes@linux.intel.com; stephen@networkplumber.org
>> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow
>> action
>> 
>> Caution: EXT Email
>> 
>> Hi Po,
>> 
>> On Wed 22 Apr 2020 at 05:48, Po Liu <Po.Liu@nxp.com> wrote:
>> > Introduce a ingress frame gate control flow action.
>> > Tc gate action does the work like this:
>> > Assume there is a gate allow specified ingress frames can be passed at
>> > specific time slot, and be dropped at specific time slot. Tc filter
>> > chooses the ingress frames, and tc gate action would specify what slot
>> > does these frames can be passed to device and what time slot would be
>> > dropped.
>> > Tc gate action would provide an entry list to tell how much time gate
>> > keep open and how much time gate keep state close. Gate action also
>> > assign a start time to tell when the entry list start. Then driver
>> > would repeat the gate entry list cyclically.
>> > For the software simulation, gate action requires the user assign a
>> > time clock type.
>> >
>> > Below is the setting example in user space. Tc filter a stream source
>> > ip address is 192.168.0.20 and gate action own two time slots. One is
>> > last 200ms gate open let frame pass another is last 100ms gate close
>> > let frames dropped. When the frames have passed total frames over
>> > 8000000 bytes, frames will be dropped in one 200000000ns time slot.
>> >
>> >> tc qdisc add dev eth0 ingress
>> >
>> >> tc filter add dev eth0 parent ffff: protocol ip \
>> >          flower src_ip 192.168.0.20 \
>> >          action gate index 2 clockid CLOCK_TAI \
>> >          sched-entry open 200000000 -1 8000000 \
>> >          sched-entry close 100000000 -1 -1
>> >
>> >> tc chain del dev eth0 ingress chain 0
>> >
>> > "sched-entry" follow the name taprio style. Gate state is
>> > "open"/"close". Follow with period nanosecond. Then next item is
>> > internal priority value means which ingress queue should put. "-1"
>> > means wildcard. The last value optional specifies the maximum number
>> > of MSDU octets that are permitted to pass the gate during the
>> > specified time interval.
>> > Base-time is not set will be 0 as default, as result start time would
>> > be ((N + 1) * cycletime) which is the minimal of future time.
>> >
>> > Below example shows filtering a stream with destination mac address is
>> > 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The
>> > gate action would run with one close time slot which means always keep
>> close.
>> > The time cycle is total 200000000ns. The base-time would calculate by:
>> >
>> >  1357000000000 + (N + 1) * cycletime
>> >
>> > When the total value is the future time, it will be the start time.
>> > The cycletime here would be 200000000ns for this case.
>> >
>> >> tc filter add dev eth0 parent ffff:  protocol ip \
>> >          flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
>> >          action gate index 12 base-time 1357000000000 \
>> >          sched-entry close 200000000 -1 -1 \
>> >          clockid CLOCK_TAI
>> >
>> > Signed-off-by: Po Liu <Po.Liu@nxp.com>
>> > ---
>> >  include/net/tc_act/tc_gate.h        |  54 +++
>> >  include/uapi/linux/pkt_cls.h        |   1 +
>> >  include/uapi/linux/tc_act/tc_gate.h |  47 ++
>> >  net/sched/Kconfig                   |  13 +
>> >  net/sched/Makefile                  |   1 +
>> >  net/sched/act_gate.c                | 647 ++++++++++++++++++++++++++++
>> >  6 files changed, 763 insertions(+)
>> >  create mode 100644 include/net/tc_act/tc_gate.h  create mode 100644
>> > include/uapi/linux/tc_act/tc_gate.h
>> >  create mode 100644 net/sched/act_gate.c
>> >
>> > diff --git a/include/net/tc_act/tc_gate.h
>> > b/include/net/tc_act/tc_gate.h new file mode 100644 index
>> > 000000000000..b0ace55b2aaa
>> > --- /dev/null
>> > +++ b/include/net/tc_act/tc_gate.h
>> > @@ -0,0 +1,54 @@
>> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> > +/* Copyright 2020 NXP */
>> > +
>> > +#ifndef __NET_TC_GATE_H
>> > +#define __NET_TC_GATE_H
>> > +
>> > +#include <net/act_api.h>
>> > +#include <linux/tc_act/tc_gate.h>
>> > +
>> > +struct tcfg_gate_entry {
>> > +     int                     index;
>> > +     u8                      gate_state;
>> > +     u32                     interval;
>> > +     s32                     ipv;
>> > +     s32                     maxoctets;
>> > +     struct list_head        list;
>> > +};
>> > +
>> > +struct tcf_gate_params {
>> > +     s32                     tcfg_priority;
>> > +     u64                     tcfg_basetime;
>> > +     u64                     tcfg_cycletime;
>> > +     u64                     tcfg_cycletime_ext;
>> > +     u32                     tcfg_flags;
>> > +     s32                     tcfg_clockid;
>> > +     size_t                  num_entries;
>> > +     struct list_head        entries;
>> > +};
>> > +
>> > +#define GATE_ACT_GATE_OPEN   BIT(0)
>> > +#define GATE_ACT_PENDING     BIT(1)
>> > +struct gate_action {
>> > +     struct tcf_gate_params param;
>> > +     spinlock_t entry_lock;
>> > +     u8 current_gate_status;
>> > +     ktime_t current_close_time;
>> > +     u32 current_entry_octets;
>> > +     s32 current_max_octets;
>> > +     struct tcfg_gate_entry __rcu *next_entry;
>> > +     struct hrtimer hitimer;
>> > +     enum tk_offsets tk_offset;
>> > +     struct rcu_head rcu;
>> > +};
>> > +
>> > +struct tcf_gate {
>> > +     struct tc_action                common;
>> > +     struct gate_action __rcu        *actg;
>> > +};
>> > +#define to_gate(a) ((struct tcf_gate *)a)
>> > +
>> > +#define get_gate_param(act) ((struct tcf_gate_params *)act) #define
>> > +get_gate_action(p) ((struct gate_action *)p)
>> > +
>> > +#endif
>> > diff --git a/include/uapi/linux/pkt_cls.h
>> > b/include/uapi/linux/pkt_cls.h index 9f06d29cab70..fc672b232437
>> 100644
>> > --- a/include/uapi/linux/pkt_cls.h
>> > +++ b/include/uapi/linux/pkt_cls.h
>> > @@ -134,6 +134,7 @@ enum tca_id {
>> >       TCA_ID_CTINFO,
>> >       TCA_ID_MPLS,
>> >       TCA_ID_CT,
>> > +     TCA_ID_GATE,
>> >       /* other actions go here */
>> >       __TCA_ID_MAX = 255
>> >  };
>> > diff --git a/include/uapi/linux/tc_act/tc_gate.h
>> > b/include/uapi/linux/tc_act/tc_gate.h
>> > new file mode 100644
>> > index 000000000000..f214b3a6d44f
>> > --- /dev/null
>> > +++ b/include/uapi/linux/tc_act/tc_gate.h
>> > @@ -0,0 +1,47 @@
>> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
>> > +/* Copyright 2020 NXP */
>> > +
>> > +#ifndef __LINUX_TC_GATE_H
>> > +#define __LINUX_TC_GATE_H
>> > +
>> > +#include <linux/pkt_cls.h>
>> > +
>> > +struct tc_gate {
>> > +     tc_gen;
>> > +};
>> > +
>> > +enum {
>> > +     TCA_GATE_ENTRY_UNSPEC,
>> > +     TCA_GATE_ENTRY_INDEX,
>> > +     TCA_GATE_ENTRY_GATE,
>> > +     TCA_GATE_ENTRY_INTERVAL,
>> > +     TCA_GATE_ENTRY_IPV,
>> > +     TCA_GATE_ENTRY_MAX_OCTETS,
>> > +     __TCA_GATE_ENTRY_MAX,
>> > +};
>> > +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
>> > +
>> > +enum {
>> > +     TCA_GATE_ONE_ENTRY_UNSPEC,
>> > +     TCA_GATE_ONE_ENTRY,
>> > +     __TCA_GATE_ONE_ENTRY_MAX,
>> > +};
>> > +#define TCA_GATE_ONE_ENTRY_MAX (__TCA_GATE_ONE_ENTRY_MAX
>> - 1)
>> > +
>> > +enum {
>> > +     TCA_GATE_UNSPEC,
>> > +     TCA_GATE_TM,
>> > +     TCA_GATE_PARMS,
>> > +     TCA_GATE_PAD,
>> > +     TCA_GATE_PRIORITY,
>> > +     TCA_GATE_ENTRY_LIST,
>> > +     TCA_GATE_BASE_TIME,
>> > +     TCA_GATE_CYCLE_TIME,
>> > +     TCA_GATE_CYCLE_TIME_EXT,
>> > +     TCA_GATE_FLAGS,
>> > +     TCA_GATE_CLOCKID,
>> > +     __TCA_GATE_MAX,
>> > +};
>> > +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
>> > +
>> > +#endif
>> > diff --git a/net/sched/Kconfig b/net/sched/Kconfig index
>> > bfbefb7bff9d..1314549c7567 100644
>> > --- a/net/sched/Kconfig
>> > +++ b/net/sched/Kconfig
>> > @@ -981,6 +981,19 @@ config NET_ACT_CT
>> >         To compile this code as a module, choose M here: the
>> >         module will be called act_ct.
>> >
>> > +config NET_ACT_GATE
>> > +     tristate "Frame gate entry list control tc action"
>> > +     depends on NET_CLS_ACT
>> > +     help
>> > +       Say Y here to allow to control the ingress flow to be passed at
>> > +       specific time slot and be dropped at other specific time slot by
>> > +       the gate entry list. The manipulation will simulate the IEEE
>> > +       802.1Qci stream gate control behavior.
>> > +
>> > +       If unsure, say N.
>> > +       To compile this code as a module, choose M here: the
>> > +       module will be called act_gate.
>> > +
>> >  config NET_IFE_SKBMARK
>> >       tristate "Support to encoding decoding skb mark on IFE action"
>> >       depends on NET_ACT_IFE
>> > diff --git a/net/sched/Makefile b/net/sched/Makefile index
>> > 31c367a6cd09..66bbf9a98f9e 100644
>> > --- a/net/sched/Makefile
>> > +++ b/net/sched/Makefile
>> > @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)       +=
>> act_meta_skbprio.o
>> >  obj-$(CONFIG_NET_IFE_SKBTCINDEX)     += act_meta_skbtcindex.o
>> >  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
>> >  obj-$(CONFIG_NET_ACT_CT)     += act_ct.o
>> > +obj-$(CONFIG_NET_ACT_GATE)   += act_gate.o
>> >  obj-$(CONFIG_NET_SCH_FIFO)   += sch_fifo.o
>> >  obj-$(CONFIG_NET_SCH_CBQ)    += sch_cbq.o
>> >  obj-$(CONFIG_NET_SCH_HTB)    += sch_htb.o
>> > diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c new file mode
>> > 100644 index 000000000000..e932f402b4f1
>> > --- /dev/null
>> > +++ b/net/sched/act_gate.c
>> > @@ -0,0 +1,647 @@
>> > +// SPDX-License-Identifier: GPL-2.0-or-later
>> > +/* Copyright 2020 NXP */
>> > +
>> > +#include <linux/module.h>
>> > +#include <linux/types.h>
>> > +#include <linux/kernel.h>
>> > +#include <linux/string.h>
>> > +#include <linux/errno.h>
>> > +#include <linux/skbuff.h>
>> > +#include <linux/rtnetlink.h>
>> > +#include <linux/init.h>
>> > +#include <linux/slab.h>
>> > +#include <net/act_api.h>
>> > +#include <net/netlink.h>
>> > +#include <net/pkt_cls.h>
>> > +#include <net/tc_act/tc_gate.h>
>> > +
>> > +static unsigned int gate_net_id;
>> > +static struct tc_action_ops act_gate_ops;
>> > +
>> > +static ktime_t gate_get_time(struct gate_action *gact) {
>> > +     ktime_t mono = ktime_get();
>> > +
>> > +     switch (gact->tk_offset) {
>> > +     case TK_OFFS_MAX:
>> > +             return mono;
>> > +     default:
>> > +             return ktime_mono_to_any(mono, gact->tk_offset);
>> > +     }
>> > +
>> > +     return KTIME_MAX;
>> > +}
>> > +
>> > +static int gate_get_start_time(struct gate_action *gact, ktime_t
>> > +*start) {
>> > +     struct tcf_gate_params *param = get_gate_param(gact);
>> > +     ktime_t now, base, cycle;
>> > +     u64 n;
>> > +
>> > +     base = ns_to_ktime(param->tcfg_basetime);
>> > +     now = gate_get_time(gact);
>> > +
>> > +     if (ktime_after(base, now)) {
>> > +             *start = base;
>> > +             return 0;
>> > +     }
>> > +
>> > +     cycle = param->tcfg_cycletime;
>> > +
>> > +     /* cycle time should not be zero */
>> > +     if (WARN_ON(!cycle))
>> > +             return -EFAULT;
>> 
>> Looking at the init code it seems that this value can be set to 0 directly
>> from netlink packet without further validation, which would allow user to
>> trigger warning here.
>
> Yes,  will avoid at ahead point.
>
>> 
>> > +
>> > +     n = div64_u64(ktime_sub_ns(now, base), cycle);
>> > +     *start = ktime_add_ns(base, (n + 1) * cycle);
>> > +     return 0;
>> > +}
>> > +
>> > +static void gate_start_timer(struct gate_action *gact, ktime_t start)
>> > +{
>> > +     ktime_t expires;
>> > +
>> > +     expires = hrtimer_get_expires(&gact->hitimer);
>> > +     if (expires == 0)
>> > +             expires = KTIME_MAX;
>> > +
>> > +     start = min_t(ktime_t, start, expires);
>> > +
>> > +     hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS); }
>> > +
>> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer) {
>> > +     struct gate_action *gact = container_of(timer, struct gate_action,
>> > +                                             hitimer);
>> > +     struct tcf_gate_params *p = get_gate_param(gact);
>> > +     struct tcfg_gate_entry *next;
>> > +     ktime_t close_time, now;
>> > +
>> > +     spin_lock(&gact->entry_lock);
>> > +
>> > +     next = rcu_dereference_protected(gact->next_entry,
>> > +
>> > + lockdep_is_held(&gact->entry_lock));
>> > +
>> > +     /* cycle start, clear pending bit, clear total octets */
>> > +     gact->current_gate_status = next->gate_state ?
>> GATE_ACT_GATE_OPEN : 0;
>> > +     gact->current_entry_octets = 0;
>> > +     gact->current_max_octets = next->maxoctets;
>> > +
>> > +     gact->current_close_time = ktime_add_ns(gact->current_close_time,
>> > +                                             next->interval);
>> > +
>> > +     close_time = gact->current_close_time;
>> > +
>> > +     if (list_is_last(&next->list, &p->entries))
>> > +             next = list_first_entry(&p->entries,
>> > +                                     struct tcfg_gate_entry, list);
>> > +     else
>> > +             next = list_next_entry(next, list);
>> > +
>> > +     now = gate_get_time(gact);
>> > +
>> > +     if (ktime_after(now, close_time)) {
>> > +             ktime_t cycle, base;
>> > +             u64 n;
>> > +
>> > +             cycle = p->tcfg_cycletime;
>> > +             base = ns_to_ktime(p->tcfg_basetime);
>> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
>> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
>> > +     }
>> > +
>> > +     rcu_assign_pointer(gact->next_entry, next);
>> > +     spin_unlock(&gact->entry_lock);
>> 
>> I have couple of question about synchronization here:
>> 
>> - Why do you need next_entry to be rcu pointer? It is only assigned here
>> with entry_lock protection and in init code before action is visible to
>> concurrent users. I don't see any unlocked rcu-protected readers here that
>> could benefit from it.
>> 
>> - Why create dedicated entry_lock instead of using already existing per-
>> action tcf_lock?
>
> Will try to use the tcf_lock for verification.
> The thoughts came from that the timer period arrived then check through the list and then update next time would take much more time.  Action function would be busy when traffic. So use a separate lock here for  
>
>> 
>> > +
>> > +     hrtimer_set_expires(&gact->hitimer, close_time);
>> > +
>> > +     return HRTIMER_RESTART;
>> > +}
>> > +
>> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
>> > +                     struct tcf_result *res) {
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct gate_action *gact;
>> > +     int action;
>> > +
>> > +     tcf_lastuse_update(&g->tcf_tm);
>> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
>> > +
>> > +     action = READ_ONCE(g->tcf_action);
>> > +     rcu_read_lock();
>> 
>> Action fastpath is already rcu read lock protected, you don't need to
>> manually obtain it.
>
> Will be removed.
>
>> 
>> > +     gact = rcu_dereference_bh(g->actg);
>> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {
>> 
>> Can't current_gate_status be concurrently modified by timer callback?
>> This function doesn't use entry_lock to synchronize with timer.
>
> Will try tcf_lock either.
>
>> 
>> > +             rcu_read_unlock();
>> > +             return action;
>> > +     }
>> > +
>> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
>> 
>> ...and here
>> 
>> > +             goto drop;
>> > +
>> > +     if (gact->current_max_octets >= 0) {
>> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
>> > +             if (gact->current_entry_octets >
>> > + gact->current_max_octets) {
>> 
>> here also.
>> 
>> > +
>> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
>> 
>> Please use tcf_action_inc_overlimit_qstats() and other wrappers for stats.
>> Otherwise it will crash if user passes TCA_ACT_FLAGS_NO_PERCPU_STATS
>> flag.
>
> The tcf_action_inc_overlimit_qstats() can't show limit counts in tc show command. Is there anything need to do? 

What do you mean? Internally tcf_action_inc_overlimit_qstats() just
calls qstats_overlimit_inc, if cpu_qstats percpu counter is not NULL:


	if (likely(a->cpu_qstats)) {
		qstats_overlimit_inc(this_cpu_ptr(a->cpu_qstats));
		return;
	}

Is there a subtle bug somewhere in this function?

>
>> 
>> > +                     goto drop;
>> > +             }
>> > +     }
>> > +     rcu_read_unlock();
>> > +
>> > +     return action;
>> > +drop:
>> > +     rcu_read_unlock();
>> > +     qstats_drop_inc(this_cpu_ptr(g->common.cpu_qstats));
>> > +     return TC_ACT_SHOT;
>> > +}
>> > +
>> > +static const struct nla_policy entry_policy[TCA_GATE_ENTRY_MAX + 1]
>> = {
>> > +     [TCA_GATE_ENTRY_INDEX]          = { .type = NLA_U32 },
>> > +     [TCA_GATE_ENTRY_GATE]           = { .type = NLA_FLAG },
>> > +     [TCA_GATE_ENTRY_INTERVAL]       = { .type = NLA_U32 },
>> > +     [TCA_GATE_ENTRY_IPV]            = { .type = NLA_S32 },
>> > +     [TCA_GATE_ENTRY_MAX_OCTETS]     = { .type = NLA_S32 },
>> > +};
>> > +
>> > +static const struct nla_policy gate_policy[TCA_GATE_MAX + 1] = {
>> > +     [TCA_GATE_PARMS]                = { .len = sizeof(struct tc_gate),
>> > +                                         .type = NLA_EXACT_LEN },
>> > +     [TCA_GATE_PRIORITY]             = { .type = NLA_S32 },
>> > +     [TCA_GATE_ENTRY_LIST]           = { .type = NLA_NESTED },
>> > +     [TCA_GATE_BASE_TIME]            = { .type = NLA_U64 },
>> > +     [TCA_GATE_CYCLE_TIME]           = { .type = NLA_U64 },
>> > +     [TCA_GATE_CYCLE_TIME_EXT]       = { .type = NLA_U64 },
>> > +     [TCA_GATE_FLAGS]                = { .type = NLA_U32 },
>> > +     [TCA_GATE_CLOCKID]              = { .type = NLA_S32 },
>> > +};
>> > +
>> > +static int fill_gate_entry(struct nlattr **tb, struct tcfg_gate_entry *entry,
>> > +                        struct netlink_ext_ack *extack) {
>> > +     u32 interval = 0;
>> > +
>> > +     entry->gate_state = nla_get_flag(tb[TCA_GATE_ENTRY_GATE]);
>> > +
>> > +     if (tb[TCA_GATE_ENTRY_INTERVAL])
>> > +             interval = nla_get_u32(tb[TCA_GATE_ENTRY_INTERVAL]);
>> > +
>> > +     if (interval == 0) {
>> > +             NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
>> > +             return -EINVAL;
>> > +     }
>> > +
>> > +     entry->interval = interval;
>> > +
>> > +     if (tb[TCA_GATE_ENTRY_IPV])
>> > +             entry->ipv = nla_get_s32(tb[TCA_GATE_ENTRY_IPV]);
>> > +     else
>> > +             entry->ipv = -1;
>> > +
>> > +     if (tb[TCA_GATE_ENTRY_MAX_OCTETS])
>> > +             entry->maxoctets =
>> nla_get_s32(tb[TCA_GATE_ENTRY_MAX_OCTETS]);
>> > +     else
>> > +             entry->maxoctets = -1;
>> > +
>> > +     return 0;
>> > +}
>> > +
>> > +static int parse_gate_entry(struct nlattr *n, struct  tcfg_gate_entry
>> *entry,
>> > +                         int index, struct netlink_ext_ack *extack) {
>> > +     struct nlattr *tb[TCA_GATE_ENTRY_MAX + 1] = { };
>> > +     int err;
>> 
>> > +     err = nla_parse_nested(tb, TCA_GATE_ENTRY_MAX, n, entry_policy,
>> extack);
>> > +     if (err < 0) {
>> > +             NL_SET_ERR_MSG(extack, "Could not parse nested entry");
>> > +             return -EINVAL;
>> > +     }
>> > +
>> > +     entry->index = index;
>> > +
>> > +     return fill_gate_entry(tb, entry, extack); }
>> > +
>> > +static int parse_gate_list(struct nlattr *list_attr,
>> > +                        struct tcf_gate_params *sched,
>> > +                        struct netlink_ext_ack *extack) {
>> > +     struct tcfg_gate_entry *entry, *e;
>> > +     struct nlattr *n;
>> > +     int err, rem;
>> > +     int i = 0;
>> > +
>> > +     if (!list_attr)
>> > +             return -EINVAL;
>> > +
>> > +     nla_for_each_nested(n, list_attr, rem) {
>> > +             if (nla_type(n) != TCA_GATE_ONE_ENTRY) {
>> > +                     NL_SET_ERR_MSG(extack, "Attribute isn't type 'entry'");
>> > +                     continue;
>> > +             }
>> > +
>> > +             entry = kzalloc(sizeof(*entry), GFP_KERNEL);
>> > +             if (!entry) {
>> > +                     NL_SET_ERR_MSG(extack, "Not enough memory for entry");
>> > +                     err = -ENOMEM;
>> > +                     goto release_list;
>> > +             }
>> > +
>> > +             err = parse_gate_entry(n, entry, i, extack);
>> > +             if (err < 0) {
>> > +                     kfree(entry);
>> > +                     goto release_list;
>> > +             }
>> > +
>> > +             list_add_tail(&entry->list, &sched->entries);
>> > +             i++;
>> > +     }
>> > +
>> > +     sched->num_entries = i;
>> > +
>> > +     return i;
>> > +
>> > +release_list:
>> > +     list_for_each_entry_safe(entry, e, &sched->entries, list) {
>> > +             list_del(&entry->list);
>> > +             kfree(entry);
>> > +     }
>> > +
>> > +     return err;
>> > +}
>> > +
>> > +static int tcf_gate_init(struct net *net, struct nlattr *nla,
>> > +                      struct nlattr *est, struct tc_action **a,
>> > +                      int ovr, int bind, bool rtnl_held,
>> > +                      struct tcf_proto *tp, u32 flags,
>> > +                      struct netlink_ext_ack *extack) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +     enum tk_offsets tk_offset = TK_OFFS_TAI;
>> > +     struct nlattr *tb[TCA_GATE_MAX + 1];
>> > +     struct tcf_chain *goto_ch = NULL;
>> > +     struct tcfg_gate_entry *next;
>> > +     struct tcf_gate_params *p;
>> > +     struct gate_action *gact;
>> > +     s32 clockid = CLOCK_TAI;
>> > +     struct tc_gate *parm;
>> > +     struct tcf_gate *g;
>> > +     int ret = 0, err;
>> > +     u64 basetime = 0;
>> > +     u32 gflags = 0;
>> > +     s32 prio = -1;
>> > +     ktime_t start;
>> > +     u32 index;
>> > +
>> > +     if (!nla)
>> > +             return -EINVAL;
>> > +
>> > +     err = nla_parse_nested(tb, TCA_GATE_MAX, nla, gate_policy, extack);
>> > +     if (err < 0)
>> > +             return err;
>> > +
>> > +     if (!tb[TCA_GATE_PARMS])
>> > +             return -EINVAL;
>> > +     parm = nla_data(tb[TCA_GATE_PARMS]);
>> > +     index = parm->index;
>> > +     err = tcf_idr_check_alloc(tn, &index, a, bind);
>> > +     if (err < 0)
>> > +             return err;
>> > +
>> > +     if (err && bind)
>> > +             return 0;
>> > +
>> > +     if (!err) {
>> > +             ret = tcf_idr_create_from_flags(tn, index, est, a,
>> > +                                             &act_gate_ops, bind, flags);
>> > +             if (ret) {
>> > +                     tcf_idr_cleanup(tn, index);
>> > +                     return ret;
>> > +             }
>> > +
>> > +             ret = ACT_P_CREATED;
>> > +     } else if (!ovr) {
>> > +             tcf_idr_release(*a, bind);
>> > +             return -EEXIST;
>> > +     }
>> > +
>> > +     if (tb[TCA_GATE_PRIORITY])
>> > +             prio = nla_get_s32(tb[TCA_GATE_PRIORITY]);
>> > +
>> > +     if (tb[TCA_GATE_BASE_TIME])
>> > +             basetime = nla_get_u64(tb[TCA_GATE_BASE_TIME]);
>> > +
>> > +     if (tb[TCA_GATE_FLAGS])
>> > +             gflags = nla_get_u32(tb[TCA_GATE_FLAGS]);
>> > +
>> > +     if (tb[TCA_GATE_CLOCKID]) {
>> > +             clockid = nla_get_s32(tb[TCA_GATE_CLOCKID]);
>> > +             switch (clockid) {
>> > +             case CLOCK_REALTIME:
>> > +                     tk_offset = TK_OFFS_REAL;
>> > +                     break;
>> > +             case CLOCK_MONOTONIC:
>> > +                     tk_offset = TK_OFFS_MAX;
>> > +                     break;
>> > +             case CLOCK_BOOTTIME:
>> > +                     tk_offset = TK_OFFS_BOOT;
>> > +                     break;
>> > +             case CLOCK_TAI:
>> > +                     tk_offset = TK_OFFS_TAI;
>> > +                     break;
>> > +             default:
>> > +                     NL_SET_ERR_MSG(extack, "Invalid 'clockid'");
>> > +                     goto release_idr;
>> > +             }
>> > +     }
>> > +
>> > +     err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
>> > +     if (err < 0)
>> > +             goto release_idr;
>> > +
>> > +     g = to_gate(*a);
>> > +
>> > +     gact = kzalloc(sizeof(*gact), GFP_KERNEL);
>> > +     if (!gact) {
>> > +             err = -ENOMEM;
>> > +             goto put_chain;
>> > +     }
>> > +
>> > +     p = get_gate_param(gact);
>> > +
>> > +     INIT_LIST_HEAD(&p->entries);
>> > +     if (tb[TCA_GATE_ENTRY_LIST]) {
>> > +             err = parse_gate_list(tb[TCA_GATE_ENTRY_LIST], p, extack);
>> > +             if (err < 0)
>> > +                     goto release_mem;
>> > +     }
>> > +
>> > +     if (tb[TCA_GATE_CYCLE_TIME]) {
>> > +             p->tcfg_cycletime = nla_get_u64(tb[TCA_GATE_CYCLE_TIME]);
>> > +     } else {
>> > +             struct tcfg_gate_entry *entry;
>> > +             ktime_t cycle = 0;
>> > +
>> > +             list_for_each_entry(entry, &p->entries, list)
>> > +                     cycle = ktime_add_ns(cycle, entry->interval);
>> > +             p->tcfg_cycletime = cycle;
>> > +     }
>> > +
>> > +     if (tb[TCA_GATE_CYCLE_TIME_EXT])
>> > +             p->tcfg_cycletime_ext =
>> > +                     nla_get_u64(tb[TCA_GATE_CYCLE_TIME_EXT]);
>> > +
>> > +     p->tcfg_priority = prio;
>> > +     p->tcfg_basetime = basetime;
>> > +     p->tcfg_clockid = clockid;
>> > +     p->tcfg_flags = gflags;
>> > +
>> > +     gact->tk_offset = tk_offset;
>> > +     spin_lock_init(&gact->entry_lock);
>> > +     hrtimer_init(&gact->hitimer, clockid, HRTIMER_MODE_ABS);
>> > +     gact->hitimer.function = gate_timer_func;
>> > +
>> > +     err = gate_get_start_time(gact, &start);
>> > +     if (err < 0) {
>> > +             NL_SET_ERR_MSG(extack,
>> > +                            "Internal error: failed get start time");
>> > +             goto release_mem;
>> > +     }
>> > +
>> > +     gact->current_close_time = start;
>> > +     gact->current_gate_status = GATE_ACT_GATE_OPEN |
>> > + GATE_ACT_PENDING;
>> > +
>> > +     next = list_first_entry(&p->entries, struct tcfg_gate_entry, list);
>> > +     rcu_assign_pointer(gact->next_entry, next);
>> > +
>> > +     gate_start_timer(gact, start);
>> > +
>> > +     spin_lock_bh(&g->tcf_lock);
>> > +     goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
>> > +     gact = rcu_replace_pointer(g->actg, gact,
>> > +                                lockdep_is_held(&g->tcf_lock));
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +
>> > +     if (goto_ch)
>> > +             tcf_chain_put_by_act(goto_ch);
>> > +     if (gact)
>> > +             kfree_rcu(gact, rcu);
>> 
>> This leaks entries. For example, tunnel key action implements
>> tunnel_key_release_params() helper that is used by both init and release
>> code. I guess that would be the best approach here as well.
>> 
>
> Will refer the tunnel action. Thanks for pointing out.
>
>> > +
>> > +     if (ret == ACT_P_CREATED)
>> > +             tcf_idr_insert(tn, *a);
>> > +     return ret;
>> > +
>> > +release_mem:
>> > +     kfree(gact);
>> > +put_chain:
>> > +     if (goto_ch)
>> > +             tcf_chain_put_by_act(goto_ch);
>> > +release_idr:
>> > +     tcf_idr_release(*a, bind);
>> > +     return err;
>> > +}
>> > +
>> > +static void tcf_gate_cleanup(struct tc_action *a) {
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct tcfg_gate_entry *entry, *n;
>> > +     struct tcf_gate_params *p;
>> > +     struct gate_action *gact;
>> > +
>> > +     spin_lock_bh(&g->tcf_lock);
>> > +     gact = rcu_dereference_protected(g->actg,
>> > +                                      lockdep_is_held(&g->tcf_lock));
>> > +     hrtimer_cancel(&gact->hitimer);
>> > +
>> > +     p = get_gate_param(gact);
>> > +     list_for_each_entry_safe(entry, n, &p->entries, list) {
>> > +             list_del(&entry->list);
>> > +             kfree(entry);
>> > +     }
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +
>> > +     kfree_rcu(gact, rcu);
>> > +}
>> > +
>> > +static int dumping_entry(struct sk_buff *skb,
>> > +                      struct tcfg_gate_entry *entry) {
>> > +     struct nlattr *item;
>> > +
>> > +     item = nla_nest_start_noflag(skb, TCA_GATE_ONE_ENTRY);
>> > +     if (!item)
>> > +             return -ENOSPC;
>> > +
>> > +     if (nla_put_u32(skb, TCA_GATE_ENTRY_INDEX, entry->index))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (entry->gate_state && nla_put_flag(skb, TCA_GATE_ENTRY_GATE))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u32(skb, TCA_GATE_ENTRY_INTERVAL, entry->interval))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_ENTRY_MAX_OCTETS, entry-
>> >maxoctets))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_ENTRY_IPV, entry->ipv))
>> > +             goto nla_put_failure;
>> > +
>> > +     return nla_nest_end(skb, item);
>> > +
>> > +nla_put_failure:
>> > +     nla_nest_cancel(skb, item);
>> > +     return -1;
>> > +}
>> > +
>> > +static int tcf_gate_dump(struct sk_buff *skb, struct tc_action *a,
>> > +                      int bind, int ref) {
>> > +     unsigned char *b = skb_tail_pointer(skb);
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct tc_gate opt = {
>> > +             .index    = g->tcf_index,
>> > +             .refcnt   = refcount_read(&g->tcf_refcnt) - ref,
>> > +             .bindcnt  = atomic_read(&g->tcf_bindcnt) - bind,
>> > +     };
>> > +     struct tcfg_gate_entry *entry;
>> > +     struct gate_action *gact;
>> > +     struct tcf_gate_params *p;
>> > +     struct nlattr *entry_list;
>> > +     struct tcf_t t;
>> > +
>> > +     spin_lock_bh(&g->tcf_lock);
>> > +     opt.action = g->tcf_action;
>> > +     gact = rcu_dereference_protected(g->actg,
>> > +                                      lockdep_is_held(&g->tcf_lock));
>> > +
>> > +     p = get_gate_param(gact);
>> > +
>> > +     if (nla_put(skb, TCA_GATE_PARMS, sizeof(opt), &opt))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u64_64bit(skb, TCA_GATE_BASE_TIME,
>> > +                           p->tcfg_basetime, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME,
>> > +                           p->tcfg_cycletime, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME_EXT,
>> > +                           p->tcfg_cycletime_ext, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_CLOCKID, p->tcfg_clockid))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u32(skb, TCA_GATE_FLAGS, p->tcfg_flags))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_PRIORITY, p->tcfg_priority))
>> > +             goto nla_put_failure;
>> > +
>> > +     entry_list = nla_nest_start_noflag(skb, TCA_GATE_ENTRY_LIST);
>> > +     if (!entry_list)
>> > +             goto nla_put_failure;
>> > +
>> > +     list_for_each_entry(entry, &p->entries, list) {
>> > +             if (dumping_entry(skb, entry) < 0)
>> > +                     goto nla_put_failure;
>> > +     }
>> > +
>> > +     nla_nest_end(skb, entry_list);
>> > +
>> > +     tcf_tm_dump(&t, &g->tcf_tm);
>> > +     if (nla_put_64bit(skb, TCA_GATE_TM, sizeof(t), &t, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +
>> > +     return skb->len;
>> > +
>> > +nla_put_failure:
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +     nlmsg_trim(skb, b);
>> > +     return -1;
>> > +}
>> > +
>> > +static int tcf_gate_walker(struct net *net, struct sk_buff *skb,
>> > +                        struct netlink_callback *cb, int type,
>> > +                        const struct tc_action_ops *ops,
>> > +                        struct netlink_ext_ack *extack) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +
>> > +     return tcf_generic_walker(tn, skb, cb, type, ops, extack); }
>> > +
>> > +static void tcf_gate_stats_update(struct tc_action *a, u64 bytes, u32
>> packets,
>> > +                               u64 lastuse, bool hw) {
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct tcf_t *tm = &g->tcf_tm;
>> > +
>> > +     tcf_action_update_stats(a, bytes, packets, false, hw);
>> > +     tm->lastuse = max_t(u64, tm->lastuse, lastuse); }
>> > +
>> > +static int tcf_gate_search(struct net *net, struct tc_action **a, u32
>> > +index) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +
>> > +     return tcf_idr_search(tn, a, index); }
>> > +
>> > +static size_t tcf_gate_get_fill_size(const struct tc_action *act) {
>> > +     return nla_total_size(sizeof(struct tc_gate)); }
>> > +
>> > +static struct tc_action_ops act_gate_ops = {
>> > +     .kind           =       "gate",
>> > +     .id             =       TCA_ID_GATE,
>> > +     .owner          =       THIS_MODULE,
>> > +     .act            =       tcf_gate_act,
>> > +     .dump           =       tcf_gate_dump,
>> > +     .init           =       tcf_gate_init,
>> > +     .cleanup        =       tcf_gate_cleanup,
>> > +     .walk           =       tcf_gate_walker,
>> > +     .stats_update   =       tcf_gate_stats_update,
>> > +     .get_fill_size  =       tcf_gate_get_fill_size,
>> > +     .lookup         =       tcf_gate_search,
>> > +     .size           =       sizeof(struct gate_action),
>> > +};
>> > +
>> > +static __net_init int gate_init_net(struct net *net) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +
>> > +     return tc_action_net_init(net, tn, &act_gate_ops); }
>> > +
>> > +static void __net_exit gate_exit_net(struct list_head *net_list) {
>> > +     tc_action_net_exit(net_list, gate_net_id); }
>> > +
>> > +static struct pernet_operations gate_net_ops = {
>> > +     .init = gate_init_net,
>> > +     .exit_batch = gate_exit_net,
>> > +     .id   = &gate_net_id,
>> > +     .size = sizeof(struct tc_action_net), };
>> > +
>> > +static int __init gate_init_module(void) {
>> > +     return tcf_register_action(&act_gate_ops, &gate_net_ops); }
>> > +
>> > +static void __exit gate_cleanup_module(void) {
>> > +     tcf_unregister_action(&act_gate_ops, &gate_net_ops); }
>> > +
>> > +module_init(gate_init_module);
>> > +module_exit(gate_cleanup_module);
>> > +MODULE_LICENSE("GPL v2");
>
> Thanks a lot.
>
> Br,
> Po Liu

> -----Original Message-----
> From: Vlad Buslov <vlad@buslov.dev>
> Sent: 2020年4月23日 15:43
> To: Po Liu <po.liu@nxp.com>
> Cc: Vlad Buslov <vlad@buslov.dev>; davem@davemloft.net; linux-
> kernel@vger.kernel.org; netdev@vger.kernel.org;
> vinicius.gomes@intel.com; Claudiu Manoil <claudiu.manoil@nxp.com>;
> Vladimir Oltean <vladimir.oltean@nxp.com>; Alexandru Marginean
> <alexandru.marginean@nxp.com>; michael.chan@broadcom.com;
> vishal@chelsio.com; saeedm@mellanox.com; leon@kernel.org;
> jiri@mellanox.com; idosch@mellanox.com;
> alexandre.belloni@bootlin.com; UNGLinuxDriver@microchip.com;
> kuba@kernel.org; jhs@mojatatu.com; xiyou.wangcong@gmail.com;
> simon.horman@netronome.com; pablo@netfilter.org;
> moshe@mellanox.com; m-karicheri2@ti.com;
> andre.guedes@linux.intel.com; stephen@networkplumber.org
> Subject: Re: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control
> flow action
> 
> Caution: EXT Email
> 
> On Thu 23 Apr 2020 at 06:14, Po Liu <po.liu@nxp.com> wrote:
> > Hi Vlad Buslov,
> >
> >> -----Original Message-----
> >> From: Vlad Buslov <vlad@buslov.dev>
> >> Sent: 2020年4月22日 21:23
> >> To: Po Liu <po.liu@nxp.com>
> >> Cc: davem@davemloft.net; linux-kernel@vger.kernel.org;
> >> netdev@vger.kernel.org; vinicius.gomes@intel.com; Claudiu Manoil
> >> <claudiu.manoil@nxp.com>; Vladimir Oltean
> <vladimir.oltean@nxp.com>;
> >> Alexandru Marginean <alexandru.marginean@nxp.com>;
> >> michael.chan@broadcom.com; vishal@chelsio.com;
> saeedm@mellanox.com;
> >> leon@kernel.org; jiri@mellanox.com; idosch@mellanox.com;
> >> alexandre.belloni@bootlin.com; UNGLinuxDriver@microchip.com;
> >> kuba@kernel.org; jhs@mojatatu.com; xiyou.wangcong@gmail.com;
> >> simon.horman@netronome.com; pablo@netfilter.org;
> moshe@mellanox.com;
> >> m-karicheri2@ti.com; andre.guedes@linux.intel.com;
> >> stephen@networkplumber.org
> >> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate
> >> control flow action
> >>
> >> Caution: EXT Email
> >>
> >> Hi Po,
> >>
> >> On Wed 22 Apr 2020 at 05:48, Po Liu <Po.Liu@nxp.com> wrote:
> >> > Introduce a ingress frame gate control flow action.
> >> > Tc gate action does the work like this:
> >> > Assume there is a gate allow specified ingress frames can be passed
> >> > at specific time slot, and be dropped at specific time slot. Tc
> >> > filter chooses the ingress frames, and tc gate action would specify
> >> > what slot does these frames can be passed to device and what time
> >> > slot would be dropped.
> >> > Tc gate action would provide an entry list to tell how much time
> >> > gate keep open and how much time gate keep state close. Gate
> action
> >> > also assign a start time to tell when the entry list start. Then
> >> > driver would repeat the gate entry list cyclically.
> >> > For the software simulation, gate action requires the user assign a
> >> > time clock type.
> >> >
> >> > Below is the setting example in user space. Tc filter a stream
> >> > source ip address is 192.168.0.20 and gate action own two time
> >> > slots. One is last 200ms gate open let frame pass another is last
> >> > 100ms gate close let frames dropped. When the frames have passed
> >> > total frames over
> >> > 8000000 bytes, frames will be dropped in one 200000000ns time slot.
> >> >
> >> >> tc qdisc add dev eth0 ingress
> >> >
> >> >> tc filter add dev eth0 parent ffff: protocol ip \
> >> >          flower src_ip 192.168.0.20 \
> >> >          action gate index 2 clockid CLOCK_TAI \
> >> >          sched-entry open 200000000 -1 8000000 \
> >> >          sched-entry close 100000000 -1 -1
> >> >
> >> >> tc chain del dev eth0 ingress chain 0
> >> >
> >> > "sched-entry" follow the name taprio style. Gate state is
> >> > "open"/"close". Follow with period nanosecond. Then next item is
> >> > internal priority value means which ingress queue should put. "-1"
> >> > means wildcard. The last value optional specifies the maximum
> >> > number of MSDU octets that are permitted to pass the gate during
> >> > the specified time interval.
> >> > Base-time is not set will be 0 as default, as result start time
> >> > would be ((N + 1) * cycletime) which is the minimal of future time.
> >> >
> >> > Below example shows filtering a stream with destination mac address
> >> > is
> >> > 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The
> >> > gate action would run with one close time slot which means always
> >> > keep
> >> close.
> >> > The time cycle is total 200000000ns. The base-time would calculate by:
> >> >
> >> >  1357000000000 + (N + 1) * cycletime
> >> >
> >> > When the total value is the future time, it will be the start time.
> >> > The cycletime here would be 200000000ns for this case.
> >> >
> >> >> tc filter add dev eth0 parent ffff:  protocol ip \
> >> >          flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
> >> >          action gate index 12 base-time 1357000000000 \
> >> >          sched-entry close 200000000 -1 -1 \
> >> >          clockid CLOCK_TAI
> >> >
> >> > Signed-off-by: Po Liu <Po.Liu@nxp.com>
> >> > ---
> >> >  include/net/tc_act/tc_gate.h        |  54 +++
> >> >  include/uapi/linux/pkt_cls.h        |   1 +
> >> >  include/uapi/linux/tc_act/tc_gate.h |  47 ++
> >> >  net/sched/Kconfig                   |  13 +
> >> >  net/sched/Makefile                  |   1 +
> >> >  net/sched/act_gate.c                | 647
> ++++++++++++++++++++++++++++
> >> >  6 files changed, 763 insertions(+)  create mode 100644
> >> > include/net/tc_act/tc_gate.h  create mode 100644
> >> > include/uapi/linux/tc_act/tc_gate.h
> >> >  create mode 100644 net/sched/act_gate.c
> >> >
> >> > diff --git a/include/net/tc_act/tc_gate.h
> >> > b/include/net/tc_act/tc_gate.h new file mode 100644 index
> >> > 000000000000..b0ace55b2aaa
> >> > --- /dev/null
> >> > +++ b/include/net/tc_act/tc_gate.h
> >> > @@ -0,0 +1,54 @@
> >> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> >> > +/* Copyright 2020 NXP */
> >> > +
> >> > +#ifndef __NET_TC_GATE_H
> >> > +#define __NET_TC_GATE_H
> >> > +
> >> > +#include <net/act_api.h>
> >> > +#include <linux/tc_act/tc_gate.h>
> >> > +
> >> > +struct tcfg_gate_entry {
> >> > +     int                     index;
> >> > +     u8                      gate_state;
> >> > +     u32                     interval;
> >> > +     s32                     ipv;
> >> > +     s32                     maxoctets;
> >> > +     struct list_head        list;
> >> > +};
> >> > +
> >> > +struct tcf_gate_params {
> >> > +     s32                     tcfg_priority;
> >> > +     u64                     tcfg_basetime;
> >> > +     u64                     tcfg_cycletime;
> >> > +     u64                     tcfg_cycletime_ext;
> >> > +     u32                     tcfg_flags;
> >> > +     s32                     tcfg_clockid;
> >> > +     size_t                  num_entries;
> >> > +     struct list_head        entries;
> >> > +};
> >> > +
> >> > +#define GATE_ACT_GATE_OPEN   BIT(0)
> >> > +#define GATE_ACT_PENDING     BIT(1)
> >> > +struct gate_action {
> >> > +     struct tcf_gate_params param;
> >> > +     spinlock_t entry_lock;
> >> > +     u8 current_gate_status;
> >> > +     ktime_t current_close_time;
> >> > +     u32 current_entry_octets;
> >> > +     s32 current_max_octets;
> >> > +     struct tcfg_gate_entry __rcu *next_entry;
> >> > +     struct hrtimer hitimer;
> >> > +     enum tk_offsets tk_offset;
> >> > +     struct rcu_head rcu;
> >> > +};
> >> > +
> >> > +struct tcf_gate {
> >> > +     struct tc_action                common;
> >> > +     struct gate_action __rcu        *actg;
> >> > +};
> >> > +#define to_gate(a) ((struct tcf_gate *)a)
> >> > +
> >> > +#define get_gate_param(act) ((struct tcf_gate_params *)act)
> >> > +#define
> >> > +get_gate_action(p) ((struct gate_action *)p)
> >> > +
> >> > +#endif
> >> > diff --git a/include/uapi/linux/pkt_cls.h
> >> > b/include/uapi/linux/pkt_cls.h index 9f06d29cab70..fc672b232437
> >> 100644
> >> > --- a/include/uapi/linux/pkt_cls.h
> >> > +++ b/include/uapi/linux/pkt_cls.h
> >> > @@ -134,6 +134,7 @@ enum tca_id {
> >> >       TCA_ID_CTINFO,
> >> >       TCA_ID_MPLS,
> >> >       TCA_ID_CT,
> >> > +     TCA_ID_GATE,
> >> >       /* other actions go here */
> >> >       __TCA_ID_MAX = 255
> >> >  };
> >> > diff --git a/include/uapi/linux/tc_act/tc_gate.h
> >> > b/include/uapi/linux/tc_act/tc_gate.h
> >> > new file mode 100644
> >> > index 000000000000..f214b3a6d44f
> >> > --- /dev/null
> >> > +++ b/include/uapi/linux/tc_act/tc_gate.h
> >> > @@ -0,0 +1,47 @@
> >> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> >> > +/* Copyright 2020 NXP */
> >> > +
> >> > +#ifndef __LINUX_TC_GATE_H
> >> > +#define __LINUX_TC_GATE_H
> >> > +
> >> > +#include <linux/pkt_cls.h>
> >> > +
> >> > +struct tc_gate {
> >> > +     tc_gen;
> >> > +};
> >> > +
> >> > +enum {
> >> > +     TCA_GATE_ENTRY_UNSPEC,
> >> > +     TCA_GATE_ENTRY_INDEX,
> >> > +     TCA_GATE_ENTRY_GATE,
> >> > +     TCA_GATE_ENTRY_INTERVAL,
> >> > +     TCA_GATE_ENTRY_IPV,
> >> > +     TCA_GATE_ENTRY_MAX_OCTETS,
> >> > +     __TCA_GATE_ENTRY_MAX,
> >> > +};
> >> > +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
> >> > +
> >> > +enum {
> >> > +     TCA_GATE_ONE_ENTRY_UNSPEC,
> >> > +     TCA_GATE_ONE_ENTRY,
> >> > +     __TCA_GATE_ONE_ENTRY_MAX,
> >> > +};
> >> > +#define TCA_GATE_ONE_ENTRY_MAX
> (__TCA_GATE_ONE_ENTRY_MAX
> >> - 1)
> >> > +
> >> > +enum {
> >> > +     TCA_GATE_UNSPEC,
> >> > +     TCA_GATE_TM,
> >> > +     TCA_GATE_PARMS,
> >> > +     TCA_GATE_PAD,
> >> > +     TCA_GATE_PRIORITY,
> >> > +     TCA_GATE_ENTRY_LIST,
> >> > +     TCA_GATE_BASE_TIME,
> >> > +     TCA_GATE_CYCLE_TIME,
> >> > +     TCA_GATE_CYCLE_TIME_EXT,
> >> > +     TCA_GATE_FLAGS,
> >> > +     TCA_GATE_CLOCKID,
> >> > +     __TCA_GATE_MAX,
> >> > +};
> >> > +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
> >> > +
> >> > +#endif
> >> > diff --git a/net/sched/Kconfig b/net/sched/Kconfig index
> >> > bfbefb7bff9d..1314549c7567 100644
> >> > --- a/net/sched/Kconfig
> >> > +++ b/net/sched/Kconfig
> >> > @@ -981,6 +981,19 @@ config NET_ACT_CT
> >> >         To compile this code as a module, choose M here: the
> >> >         module will be called act_ct.
> >> >
> >> > +config NET_ACT_GATE
> >> > +     tristate "Frame gate entry list control tc action"
> >> > +     depends on NET_CLS_ACT
> >> > +     help
> >> > +       Say Y here to allow to control the ingress flow to be passed at
> >> > +       specific time slot and be dropped at other specific time slot by
> >> > +       the gate entry list. The manipulation will simulate the IEEE
> >> > +       802.1Qci stream gate control behavior.
> >> > +
> >> > +       If unsure, say N.
> >> > +       To compile this code as a module, choose M here: the
> >> > +       module will be called act_gate.
> >> > +
> >> >  config NET_IFE_SKBMARK
> >> >       tristate "Support to encoding decoding skb mark on IFE action"
> >> >       depends on NET_ACT_IFE
> >> > diff --git a/net/sched/Makefile b/net/sched/Makefile index
> >> > 31c367a6cd09..66bbf9a98f9e 100644
> >> > --- a/net/sched/Makefile
> >> > +++ b/net/sched/Makefile
> >> > @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)       +=
> >> act_meta_skbprio.o
> >> >  obj-$(CONFIG_NET_IFE_SKBTCINDEX)     += act_meta_skbtcindex.o
> >> >  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
> >> >  obj-$(CONFIG_NET_ACT_CT)     += act_ct.o
> >> > +obj-$(CONFIG_NET_ACT_GATE)   += act_gate.o
> >> >  obj-$(CONFIG_NET_SCH_FIFO)   += sch_fifo.o
> >> >  obj-$(CONFIG_NET_SCH_CBQ)    += sch_cbq.o
> >> >  obj-$(CONFIG_NET_SCH_HTB)    += sch_htb.o
> >> > diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c new file
> >> > mode
> >> > 100644 index 000000000000..e932f402b4f1
> >> > --- /dev/null
> >> > +++ b/net/sched/act_gate.c
> >> > @@ -0,0 +1,647 @@
> >> > +// SPDX-License-Identifier: GPL-2.0-or-later
> >> > +/* Copyright 2020 NXP */
> >> > +
> >> > +#include <linux/module.h>
> >> > +#include <linux/types.h>
> >> > +#include <linux/kernel.h>
> >> > +#include <linux/string.h>
> >> > +#include <linux/errno.h>
> >> > +#include <linux/skbuff.h>
> >> > +#include <linux/rtnetlink.h>
> >> > +#include <linux/init.h>
> >> > +#include <linux/slab.h>
> >> > +#include <net/act_api.h>
> >> > +#include <net/netlink.h>
> >> > +#include <net/pkt_cls.h>
> >> > +#include <net/tc_act/tc_gate.h>
> >> > +
> >> > +static unsigned int gate_net_id;
> >> > +static struct tc_action_ops act_gate_ops;
> >> > +
> >> > +static ktime_t gate_get_time(struct gate_action *gact) {
> >> > +     ktime_t mono = ktime_get();
> >> > +
> >> > +     switch (gact->tk_offset) {
> >> > +     case TK_OFFS_MAX:
> >> > +             return mono;
> >> > +     default:
> >> > +             return ktime_mono_to_any(mono, gact->tk_offset);
> >> > +     }
> >> > +
> >> > +     return KTIME_MAX;
> >> > +}
> >> > +
> >> > +static int gate_get_start_time(struct gate_action *gact, ktime_t
> >> > +*start) {
> >> > +     struct tcf_gate_params *param = get_gate_param(gact);
> >> > +     ktime_t now, base, cycle;
> >> > +     u64 n;
> >> > +
> >> > +     base = ns_to_ktime(param->tcfg_basetime);
> >> > +     now = gate_get_time(gact);
> >> > +
> >> > +     if (ktime_after(base, now)) {
> >> > +             *start = base;
> >> > +             return 0;
> >> > +     }
> >> > +
> >> > +     cycle = param->tcfg_cycletime;
> >> > +
> >> > +     /* cycle time should not be zero */
> >> > +     if (WARN_ON(!cycle))
> >> > +             return -EFAULT;
> >>
> >> Looking at the init code it seems that this value can be set to 0
> >> directly from netlink packet without further validation, which would
> >> allow user to trigger warning here.
> >
> > Yes,  will avoid at ahead point.
> >
> >>
> >> > +
> >> > +     n = div64_u64(ktime_sub_ns(now, base), cycle);
> >> > +     *start = ktime_add_ns(base, (n + 1) * cycle);
> >> > +     return 0;
> >> > +}
> >> > +
> >> > +static void gate_start_timer(struct gate_action *gact, ktime_t
> >> > +start) {
> >> > +     ktime_t expires;
> >> > +
> >> > +     expires = hrtimer_get_expires(&gact->hitimer);
> >> > +     if (expires == 0)
> >> > +             expires = KTIME_MAX;
> >> > +
> >> > +     start = min_t(ktime_t, start, expires);
> >> > +
> >> > +     hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS); }
> >> > +
> >> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer) {
> >> > +     struct gate_action *gact = container_of(timer, struct gate_action,
> >> > +                                             hitimer);
> >> > +     struct tcf_gate_params *p = get_gate_param(gact);
> >> > +     struct tcfg_gate_entry *next;
> >> > +     ktime_t close_time, now;
> >> > +
> >> > +     spin_lock(&gact->entry_lock);
> >> > +
> >> > +     next = rcu_dereference_protected(gact->next_entry,
> >> > +
> >> > + lockdep_is_held(&gact->entry_lock));
> >> > +
> >> > +     /* cycle start, clear pending bit, clear total octets */
> >> > +     gact->current_gate_status = next->gate_state ?
> >> GATE_ACT_GATE_OPEN : 0;
> >> > +     gact->current_entry_octets = 0;
> >> > +     gact->current_max_octets = next->maxoctets;
> >> > +
> >> > +     gact->current_close_time = ktime_add_ns(gact-
> >current_close_time,
> >> > +                                             next->interval);
> >> > +
> >> > +     close_time = gact->current_close_time;
> >> > +
> >> > +     if (list_is_last(&next->list, &p->entries))
> >> > +             next = list_first_entry(&p->entries,
> >> > +                                     struct tcfg_gate_entry, list);
> >> > +     else
> >> > +             next = list_next_entry(next, list);
> >> > +
> >> > +     now = gate_get_time(gact);
> >> > +
> >> > +     if (ktime_after(now, close_time)) {
> >> > +             ktime_t cycle, base;
> >> > +             u64 n;
> >> > +
> >> > +             cycle = p->tcfg_cycletime;
> >> > +             base = ns_to_ktime(p->tcfg_basetime);
> >> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
> >> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
> >> > +     }
> >> > +
> >> > +     rcu_assign_pointer(gact->next_entry, next);
> >> > +     spin_unlock(&gact->entry_lock);
> >>
> >> I have couple of question about synchronization here:
> >>
> >> - Why do you need next_entry to be rcu pointer? It is only assigned
> >> here with entry_lock protection and in init code before action is
> >> visible to concurrent users. I don't see any unlocked rcu-protected
> >> readers here that could benefit from it.
> >>
> >> - Why create dedicated entry_lock instead of using already existing
> >> per- action tcf_lock?
> >
> > Will try to use the tcf_lock for verification.
> > The thoughts came from that the timer period arrived then check
> > through the list and then update next time would take much more time.
> > Action function would be busy when traffic. So use a separate lock
> > here for
> >
> >>
> >> > +
> >> > +     hrtimer_set_expires(&gact->hitimer, close_time);
> >> > +
> >> > +     return HRTIMER_RESTART;
> >> > +}
> >> > +
> >> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
> >> > +                     struct tcf_result *res) {
> >> > +     struct tcf_gate *g = to_gate(a);
> >> > +     struct gate_action *gact;
> >> > +     int action;
> >> > +
> >> > +     tcf_lastuse_update(&g->tcf_tm);
> >> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
> >> > +
> >> > +     action = READ_ONCE(g->tcf_action);
> >> > +     rcu_read_lock();
> >>
> >> Action fastpath is already rcu read lock protected, you don't need to
> >> manually obtain it.
> >
> > Will be removed.
> >
> >>
> >> > +     gact = rcu_dereference_bh(g->actg);
> >> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {
> >>
> >> Can't current_gate_status be concurrently modified by timer callback?
> >> This function doesn't use entry_lock to synchronize with timer.
> >
> > Will try tcf_lock either.
> >
> >>
> >> > +             rcu_read_unlock();
> >> > +             return action;
> >> > +     }
> >> > +
> >> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
> >>
> >> ...and here
> >>
> >> > +             goto drop;
> >> > +
> >> > +     if (gact->current_max_octets >= 0) {
> >> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
> >> > +             if (gact->current_entry_octets >
> >> > + gact->current_max_octets) {
> >>
> >> here also.
> >>
> >> > +
> >> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
> >>
> >> Please use tcf_action_inc_overlimit_qstats() and other wrappers for
> stats.
> >> Otherwise it will crash if user passes
> TCA_ACT_FLAGS_NO_PERCPU_STATS
> >> flag.
> >
> > The tcf_action_inc_overlimit_qstats() can't show limit counts in tc show
> command. Is there anything need to do?
> 
> What do you mean? Internally tcf_action_inc_overlimit_qstats() just calls
> qstats_overlimit_inc, if cpu_qstats percpu counter is not NULL:
> 
> 
>         if (likely(a->cpu_qstats)) {
>                 qstats_overlimit_inc(this_cpu_ptr(a->cpu_qstats));
>                 return;
>         }
> 
> Is there a subtle bug somewhere in this function?

Sorry, I updated using the tcf_action_*, and the counting is ok. I moved back to the qstats_overlimit_inc() because tcf_action_* () include the spin_lock(&a->tcfa_lock). 
I would update to  tcf_action_* () increate. 

> 
> >
> > Br,
> > Po Liu

Thanks a lot.

Br,
Po Liu

Hi Vlad Buslov,

> > >> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer)
> {
> > >> > +     struct gate_action *gact = container_of(timer, struct
> gate_action,
> > >> > +                                             hitimer);
> > >> > +     struct tcf_gate_params *p = get_gate_param(gact);
> > >> > +     struct tcfg_gate_entry *next;
> > >> > +     ktime_t close_time, now;
> > >> > +
> > >> > +     spin_lock(&gact->entry_lock);
> > >> > +
> > >> > +     next = rcu_dereference_protected(gact->next_entry,
> > >> > +
> > >> > + lockdep_is_held(&gact->entry_lock));
> > >> > +
> > >> > +     /* cycle start, clear pending bit, clear total octets */
> > >> > +     gact->current_gate_status = next->gate_state ?
> > >> GATE_ACT_GATE_OPEN : 0;
> > >> > +     gact->current_entry_octets = 0;
> > >> > +     gact->current_max_octets = next->maxoctets;
> > >> > +
> > >> > +     gact->current_close_time = ktime_add_ns(gact-
> > >current_close_time,
> > >> > +                                             next->interval);
> > >> > +
> > >> > +     close_time = gact->current_close_time;
> > >> > +
> > >> > +     if (list_is_last(&next->list, &p->entries))
> > >> > +             next = list_first_entry(&p->entries,
> > >> > +                                     struct tcfg_gate_entry, list);
> > >> > +     else
> > >> > +             next = list_next_entry(next, list);
> > >> > +
> > >> > +     now = gate_get_time(gact);
> > >> > +
> > >> > +     if (ktime_after(now, close_time)) {
> > >> > +             ktime_t cycle, base;
> > >> > +             u64 n;
> > >> > +
> > >> > +             cycle = p->tcfg_cycletime;
> > >> > +             base = ns_to_ktime(p->tcfg_basetime);
> > >> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
> > >> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
> > >> > +     }
> > >> > +
> > >> > +     rcu_assign_pointer(gact->next_entry, next);
> > >> > +     spin_unlock(&gact->entry_lock);
> > >>
> > >> I have couple of question about synchronization here:
> > >>
> > >> - Why do you need next_entry to be rcu pointer? It is only assigned
> > >> here with entry_lock protection and in init code before action is
> > >> visible to concurrent users. I don't see any unlocked rcu-protected
> > >> readers here that could benefit from it.
> > >>
> > >> - Why create dedicated entry_lock instead of using already existing
> > >> per- action tcf_lock?
> > >
> > > Will try to use the tcf_lock for verification.

I think I added entry_lock was that I can't get the tc_action common parameter in this  timer function. If I insist to use the tcf_lock, I have to move the hrtimer to struct tcf_gate which has tc_action common.
What do you think?

> > > The thoughts came from that the timer period arrived then check
> > > through the list and then update next time would take much more
> time.
> > > Action function would be busy when traffic. So use a separate lock
> > > here for
> > >
> > >>
> > >> > +
> > >> > +     hrtimer_set_expires(&gact->hitimer, close_time);
> > >> > +
> > >> > +     return HRTIMER_RESTART;
> > >> > +}
> > >> > +
> > >> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
> > >> > +                     struct tcf_result *res) {
> > >> > +     struct tcf_gate *g = to_gate(a);
> > >> > +     struct gate_action *gact;
> > >> > +     int action;
> > >> > +
> > >> > +     tcf_lastuse_update(&g->tcf_tm);
> > >> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
> > >> > +
> > >> > +     action = READ_ONCE(g->tcf_action);
> > >> > +     rcu_read_lock();
> > >>
> > >> Action fastpath is already rcu read lock protected, you don't need
> > >> to manually obtain it.
> > >
> > > Will be removed.
> > >
> > >>
> > >> > +     gact = rcu_dereference_bh(g->actg);
> > >> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING))
> > >> > + {
> > >>
> > >> Can't current_gate_status be concurrently modified by timer callback?
> > >> This function doesn't use entry_lock to synchronize with timer.
> > >
> > > Will try tcf_lock either.
> > >
> > >>
> > >> > +             rcu_read_unlock();
> > >> > +             return action;
> > >> > +     }
> > >> > +
> > >> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
> > >>
> > >> ...and here
> > >>
> > >> > +             goto drop;
> > >> > +
> > >> > +     if (gact->current_max_octets >= 0) {
> > >> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
> > >> > +             if (gact->current_entry_octets >
> > >> > + gact->current_max_octets) {
> > >>
> > >> here also.
> > >>
> > >> > +
> > >> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
> > >>
> > >> Please use tcf_action_inc_overlimit_qstats() and other wrappers for
> > stats.
> > >> Otherwise it will crash if user passes
> > TCA_ACT_FLAGS_NO_PERCPU_STATS
> > >> flag.
> > >
> > > The tcf_action_inc_overlimit_qstats() can't show limit counts in tc
> > > show
> > command. Is there anything need to do?
> >
> > What do you mean? Internally tcf_action_inc_overlimit_qstats() just
> > calls qstats_overlimit_inc, if cpu_qstats percpu counter is not NULL:
> >
> >
> >         if (likely(a->cpu_qstats)) {
> >                 qstats_overlimit_inc(this_cpu_ptr(a->cpu_qstats));
> >                 return;
> >         }
> >
> > Is there a subtle bug somewhere in this function?
> 
> Sorry, I updated using the tcf_action_*, and the counting is ok. I moved
> back to the qstats_overlimit_inc() because tcf_action_* () include the
> spin_lock(&a->tcfa_lock).
> I would update to  tcf_action_* () increate.
> 
> >
> > >
> > > Br,
> > > Po Liu
> 
> Thanks a lot.
> 
> Br,
> Po Liu

Thanks a lot.

Br,
Po Liu

On Thu 23 Apr 2020 at 11:32, Po Liu <po.liu@nxp.com> wrote:
>> -----Original Message-----
>> From: Vlad Buslov <vlad@buslov.dev>
>> Sent: 2020年4月23日 15:43
>> To: Po Liu <po.liu@nxp.com>
>> Cc: Vlad Buslov <vlad@buslov.dev>; davem@davemloft.net; linux-
>> kernel@vger.kernel.org; netdev@vger.kernel.org;
>> vinicius.gomes@intel.com; Claudiu Manoil <claudiu.manoil@nxp.com>;
>> Vladimir Oltean <vladimir.oltean@nxp.com>; Alexandru Marginean
>> <alexandru.marginean@nxp.com>; michael.chan@broadcom.com;
>> vishal@chelsio.com; saeedm@mellanox.com; leon@kernel.org;
>> jiri@mellanox.com; idosch@mellanox.com;
>> alexandre.belloni@bootlin.com; UNGLinuxDriver@microchip.com;
>> kuba@kernel.org; jhs@mojatatu.com; xiyou.wangcong@gmail.com;
>> simon.horman@netronome.com; pablo@netfilter.org;
>> moshe@mellanox.com; m-karicheri2@ti.com;
>> andre.guedes@linux.intel.com; stephen@networkplumber.org
>> Subject: Re: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control
>> flow action
>> 
>> Caution: EXT Email
>> 
>> On Thu 23 Apr 2020 at 06:14, Po Liu <po.liu@nxp.com> wrote:
>> > Hi Vlad Buslov,
>> >
>> >> -----Original Message-----
>> >> From: Vlad Buslov <vlad@buslov.dev>
>> >> Sent: 2020年4月22日 21:23
>> >> To: Po Liu <po.liu@nxp.com>
>> >> Cc: davem@davemloft.net; linux-kernel@vger.kernel.org;
>> >> netdev@vger.kernel.org; vinicius.gomes@intel.com; Claudiu Manoil
>> >> <claudiu.manoil@nxp.com>; Vladimir Oltean
>> <vladimir.oltean@nxp.com>;
>> >> Alexandru Marginean <alexandru.marginean@nxp.com>;
>> >> michael.chan@broadcom.com; vishal@chelsio.com;
>> saeedm@mellanox.com;
>> >> leon@kernel.org; jiri@mellanox.com; idosch@mellanox.com;
>> >> alexandre.belloni@bootlin.com; UNGLinuxDriver@microchip.com;
>> >> kuba@kernel.org; jhs@mojatatu.com; xiyou.wangcong@gmail.com;
>> >> simon.horman@netronome.com; pablo@netfilter.org;
>> moshe@mellanox.com;
>> >> m-karicheri2@ti.com; andre.guedes@linux.intel.com;
>> >> stephen@networkplumber.org
>> >> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate
>> >> control flow action
>> >>
>> >> Caution: EXT Email
>> >>
>> >> Hi Po,
>> >>
>> >> On Wed 22 Apr 2020 at 05:48, Po Liu <Po.Liu@nxp.com> wrote:
>> >> > Introduce a ingress frame gate control flow action.
>> >> > Tc gate action does the work like this:
>> >> > Assume there is a gate allow specified ingress frames can be passed
>> >> > at specific time slot, and be dropped at specific time slot. Tc
>> >> > filter chooses the ingress frames, and tc gate action would specify
>> >> > what slot does these frames can be passed to device and what time
>> >> > slot would be dropped.
>> >> > Tc gate action would provide an entry list to tell how much time
>> >> > gate keep open and how much time gate keep state close. Gate
>> action
>> >> > also assign a start time to tell when the entry list start. Then
>> >> > driver would repeat the gate entry list cyclically.
>> >> > For the software simulation, gate action requires the user assign a
>> >> > time clock type.
>> >> >
>> >> > Below is the setting example in user space. Tc filter a stream
>> >> > source ip address is 192.168.0.20 and gate action own two time
>> >> > slots. One is last 200ms gate open let frame pass another is last
>> >> > 100ms gate close let frames dropped. When the frames have passed
>> >> > total frames over
>> >> > 8000000 bytes, frames will be dropped in one 200000000ns time slot.
>> >> >
>> >> >> tc qdisc add dev eth0 ingress
>> >> >
>> >> >> tc filter add dev eth0 parent ffff: protocol ip \
>> >> >          flower src_ip 192.168.0.20 \
>> >> >          action gate index 2 clockid CLOCK_TAI \
>> >> >          sched-entry open 200000000 -1 8000000 \
>> >> >          sched-entry close 100000000 -1 -1
>> >> >
>> >> >> tc chain del dev eth0 ingress chain 0
>> >> >
>> >> > "sched-entry" follow the name taprio style. Gate state is
>> >> > "open"/"close". Follow with period nanosecond. Then next item is
>> >> > internal priority value means which ingress queue should put. "-1"
>> >> > means wildcard. The last value optional specifies the maximum
>> >> > number of MSDU octets that are permitted to pass the gate during
>> >> > the specified time interval.
>> >> > Base-time is not set will be 0 as default, as result start time
>> >> > would be ((N + 1) * cycletime) which is the minimal of future time.
>> >> >
>> >> > Below example shows filtering a stream with destination mac address
>> >> > is
>> >> > 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The
>> >> > gate action would run with one close time slot which means always
>> >> > keep
>> >> close.
>> >> > The time cycle is total 200000000ns. The base-time would calculate by:
>> >> >
>> >> >  1357000000000 + (N + 1) * cycletime
>> >> >
>> >> > When the total value is the future time, it will be the start time.
>> >> > The cycletime here would be 200000000ns for this case.
>> >> >
>> >> >> tc filter add dev eth0 parent ffff:  protocol ip \
>> >> >          flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
>> >> >          action gate index 12 base-time 1357000000000 \
>> >> >          sched-entry close 200000000 -1 -1 \
>> >> >          clockid CLOCK_TAI
>> >> >
>> >> > Signed-off-by: Po Liu <Po.Liu@nxp.com>
>> >> > ---
>> >> >  include/net/tc_act/tc_gate.h        |  54 +++
>> >> >  include/uapi/linux/pkt_cls.h        |   1 +
>> >> >  include/uapi/linux/tc_act/tc_gate.h |  47 ++
>> >> >  net/sched/Kconfig                   |  13 +
>> >> >  net/sched/Makefile                  |   1 +
>> >> >  net/sched/act_gate.c                | 647
>> ++++++++++++++++++++++++++++
>> >> >  6 files changed, 763 insertions(+)  create mode 100644
>> >> > include/net/tc_act/tc_gate.h  create mode 100644
>> >> > include/uapi/linux/tc_act/tc_gate.h
>> >> >  create mode 100644 net/sched/act_gate.c
>> >> >
>> >> > diff --git a/include/net/tc_act/tc_gate.h
>> >> > b/include/net/tc_act/tc_gate.h new file mode 100644 index
>> >> > 000000000000..b0ace55b2aaa
>> >> > --- /dev/null
>> >> > +++ b/include/net/tc_act/tc_gate.h
>> >> > @@ -0,0 +1,54 @@
>> >> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> >> > +/* Copyright 2020 NXP */
>> >> > +
>> >> > +#ifndef __NET_TC_GATE_H
>> >> > +#define __NET_TC_GATE_H
>> >> > +
>> >> > +#include <net/act_api.h>
>> >> > +#include <linux/tc_act/tc_gate.h>
>> >> > +
>> >> > +struct tcfg_gate_entry {
>> >> > +     int                     index;
>> >> > +     u8                      gate_state;
>> >> > +     u32                     interval;
>> >> > +     s32                     ipv;
>> >> > +     s32                     maxoctets;
>> >> > +     struct list_head        list;
>> >> > +};
>> >> > +
>> >> > +struct tcf_gate_params {
>> >> > +     s32                     tcfg_priority;
>> >> > +     u64                     tcfg_basetime;
>> >> > +     u64                     tcfg_cycletime;
>> >> > +     u64                     tcfg_cycletime_ext;
>> >> > +     u32                     tcfg_flags;
>> >> > +     s32                     tcfg_clockid;
>> >> > +     size_t                  num_entries;
>> >> > +     struct list_head        entries;
>> >> > +};
>> >> > +
>> >> > +#define GATE_ACT_GATE_OPEN   BIT(0)
>> >> > +#define GATE_ACT_PENDING     BIT(1)
>> >> > +struct gate_action {
>> >> > +     struct tcf_gate_params param;
>> >> > +     spinlock_t entry_lock;
>> >> > +     u8 current_gate_status;
>> >> > +     ktime_t current_close_time;
>> >> > +     u32 current_entry_octets;
>> >> > +     s32 current_max_octets;
>> >> > +     struct tcfg_gate_entry __rcu *next_entry;
>> >> > +     struct hrtimer hitimer;
>> >> > +     enum tk_offsets tk_offset;
>> >> > +     struct rcu_head rcu;
>> >> > +};
>> >> > +
>> >> > +struct tcf_gate {
>> >> > +     struct tc_action                common;
>> >> > +     struct gate_action __rcu        *actg;
>> >> > +};
>> >> > +#define to_gate(a) ((struct tcf_gate *)a)
>> >> > +
>> >> > +#define get_gate_param(act) ((struct tcf_gate_params *)act)
>> >> > +#define
>> >> > +get_gate_action(p) ((struct gate_action *)p)
>> >> > +
>> >> > +#endif
>> >> > diff --git a/include/uapi/linux/pkt_cls.h
>> >> > b/include/uapi/linux/pkt_cls.h index 9f06d29cab70..fc672b232437
>> >> 100644
>> >> > --- a/include/uapi/linux/pkt_cls.h
>> >> > +++ b/include/uapi/linux/pkt_cls.h
>> >> > @@ -134,6 +134,7 @@ enum tca_id {
>> >> >       TCA_ID_CTINFO,
>> >> >       TCA_ID_MPLS,
>> >> >       TCA_ID_CT,
>> >> > +     TCA_ID_GATE,
>> >> >       /* other actions go here */
>> >> >       __TCA_ID_MAX = 255
>> >> >  };
>> >> > diff --git a/include/uapi/linux/tc_act/tc_gate.h
>> >> > b/include/uapi/linux/tc_act/tc_gate.h
>> >> > new file mode 100644
>> >> > index 000000000000..f214b3a6d44f
>> >> > --- /dev/null
>> >> > +++ b/include/uapi/linux/tc_act/tc_gate.h
>> >> > @@ -0,0 +1,47 @@
>> >> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
>> >> > +/* Copyright 2020 NXP */
>> >> > +
>> >> > +#ifndef __LINUX_TC_GATE_H
>> >> > +#define __LINUX_TC_GATE_H
>> >> > +
>> >> > +#include <linux/pkt_cls.h>
>> >> > +
>> >> > +struct tc_gate {
>> >> > +     tc_gen;
>> >> > +};
>> >> > +
>> >> > +enum {
>> >> > +     TCA_GATE_ENTRY_UNSPEC,
>> >> > +     TCA_GATE_ENTRY_INDEX,
>> >> > +     TCA_GATE_ENTRY_GATE,
>> >> > +     TCA_GATE_ENTRY_INTERVAL,
>> >> > +     TCA_GATE_ENTRY_IPV,
>> >> > +     TCA_GATE_ENTRY_MAX_OCTETS,
>> >> > +     __TCA_GATE_ENTRY_MAX,
>> >> > +};
>> >> > +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
>> >> > +
>> >> > +enum {
>> >> > +     TCA_GATE_ONE_ENTRY_UNSPEC,
>> >> > +     TCA_GATE_ONE_ENTRY,
>> >> > +     __TCA_GATE_ONE_ENTRY_MAX,
>> >> > +};
>> >> > +#define TCA_GATE_ONE_ENTRY_MAX
>> (__TCA_GATE_ONE_ENTRY_MAX
>> >> - 1)
>> >> > +
>> >> > +enum {
>> >> > +     TCA_GATE_UNSPEC,
>> >> > +     TCA_GATE_TM,
>> >> > +     TCA_GATE_PARMS,
>> >> > +     TCA_GATE_PAD,
>> >> > +     TCA_GATE_PRIORITY,
>> >> > +     TCA_GATE_ENTRY_LIST,
>> >> > +     TCA_GATE_BASE_TIME,
>> >> > +     TCA_GATE_CYCLE_TIME,
>> >> > +     TCA_GATE_CYCLE_TIME_EXT,
>> >> > +     TCA_GATE_FLAGS,
>> >> > +     TCA_GATE_CLOCKID,
>> >> > +     __TCA_GATE_MAX,
>> >> > +};
>> >> > +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
>> >> > +
>> >> > +#endif
>> >> > diff --git a/net/sched/Kconfig b/net/sched/Kconfig index
>> >> > bfbefb7bff9d..1314549c7567 100644
>> >> > --- a/net/sched/Kconfig
>> >> > +++ b/net/sched/Kconfig
>> >> > @@ -981,6 +981,19 @@ config NET_ACT_CT
>> >> >         To compile this code as a module, choose M here: the
>> >> >         module will be called act_ct.
>> >> >
>> >> > +config NET_ACT_GATE
>> >> > +     tristate "Frame gate entry list control tc action"
>> >> > +     depends on NET_CLS_ACT
>> >> > +     help
>> >> > +       Say Y here to allow to control the ingress flow to be passed at
>> >> > +       specific time slot and be dropped at other specific time slot by
>> >> > +       the gate entry list. The manipulation will simulate the IEEE
>> >> > +       802.1Qci stream gate control behavior.
>> >> > +
>> >> > +       If unsure, say N.
>> >> > +       To compile this code as a module, choose M here: the
>> >> > +       module will be called act_gate.
>> >> > +
>> >> >  config NET_IFE_SKBMARK
>> >> >       tristate "Support to encoding decoding skb mark on IFE action"
>> >> >       depends on NET_ACT_IFE
>> >> > diff --git a/net/sched/Makefile b/net/sched/Makefile index
>> >> > 31c367a6cd09..66bbf9a98f9e 100644
>> >> > --- a/net/sched/Makefile
>> >> > +++ b/net/sched/Makefile
>> >> > @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)       +=
>> >> act_meta_skbprio.o
>> >> >  obj-$(CONFIG_NET_IFE_SKBTCINDEX)     += act_meta_skbtcindex.o
>> >> >  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
>> >> >  obj-$(CONFIG_NET_ACT_CT)     += act_ct.o
>> >> > +obj-$(CONFIG_NET_ACT_GATE)   += act_gate.o
>> >> >  obj-$(CONFIG_NET_SCH_FIFO)   += sch_fifo.o
>> >> >  obj-$(CONFIG_NET_SCH_CBQ)    += sch_cbq.o
>> >> >  obj-$(CONFIG_NET_SCH_HTB)    += sch_htb.o
>> >> > diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c new file
>> >> > mode
>> >> > 100644 index 000000000000..e932f402b4f1
>> >> > --- /dev/null
>> >> > +++ b/net/sched/act_gate.c
>> >> > @@ -0,0 +1,647 @@
>> >> > +// SPDX-License-Identifier: GPL-2.0-or-later
>> >> > +/* Copyright 2020 NXP */
>> >> > +
>> >> > +#include <linux/module.h>
>> >> > +#include <linux/types.h>
>> >> > +#include <linux/kernel.h>
>> >> > +#include <linux/string.h>
>> >> > +#include <linux/errno.h>
>> >> > +#include <linux/skbuff.h>
>> >> > +#include <linux/rtnetlink.h>
>> >> > +#include <linux/init.h>
>> >> > +#include <linux/slab.h>
>> >> > +#include <net/act_api.h>
>> >> > +#include <net/netlink.h>
>> >> > +#include <net/pkt_cls.h>
>> >> > +#include <net/tc_act/tc_gate.h>
>> >> > +
>> >> > +static unsigned int gate_net_id;
>> >> > +static struct tc_action_ops act_gate_ops;
>> >> > +
>> >> > +static ktime_t gate_get_time(struct gate_action *gact) {
>> >> > +     ktime_t mono = ktime_get();
>> >> > +
>> >> > +     switch (gact->tk_offset) {
>> >> > +     case TK_OFFS_MAX:
>> >> > +             return mono;
>> >> > +     default:
>> >> > +             return ktime_mono_to_any(mono, gact->tk_offset);
>> >> > +     }
>> >> > +
>> >> > +     return KTIME_MAX;
>> >> > +}
>> >> > +
>> >> > +static int gate_get_start_time(struct gate_action *gact, ktime_t
>> >> > +*start) {
>> >> > +     struct tcf_gate_params *param = get_gate_param(gact);
>> >> > +     ktime_t now, base, cycle;
>> >> > +     u64 n;
>> >> > +
>> >> > +     base = ns_to_ktime(param->tcfg_basetime);
>> >> > +     now = gate_get_time(gact);
>> >> > +
>> >> > +     if (ktime_after(base, now)) {
>> >> > +             *start = base;
>> >> > +             return 0;
>> >> > +     }
>> >> > +
>> >> > +     cycle = param->tcfg_cycletime;
>> >> > +
>> >> > +     /* cycle time should not be zero */
>> >> > +     if (WARN_ON(!cycle))
>> >> > +             return -EFAULT;
>> >>
>> >> Looking at the init code it seems that this value can be set to 0
>> >> directly from netlink packet without further validation, which would
>> >> allow user to trigger warning here.
>> >
>> > Yes,  will avoid at ahead point.
>> >
>> >>
>> >> > +
>> >> > +     n = div64_u64(ktime_sub_ns(now, base), cycle);
>> >> > +     *start = ktime_add_ns(base, (n + 1) * cycle);
>> >> > +     return 0;
>> >> > +}
>> >> > +
>> >> > +static void gate_start_timer(struct gate_action *gact, ktime_t
>> >> > +start) {
>> >> > +     ktime_t expires;
>> >> > +
>> >> > +     expires = hrtimer_get_expires(&gact->hitimer);
>> >> > +     if (expires == 0)
>> >> > +             expires = KTIME_MAX;
>> >> > +
>> >> > +     start = min_t(ktime_t, start, expires);
>> >> > +
>> >> > +     hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS); }
>> >> > +
>> >> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer) {
>> >> > +     struct gate_action *gact = container_of(timer, struct gate_action,
>> >> > +                                             hitimer);
>> >> > +     struct tcf_gate_params *p = get_gate_param(gact);
>> >> > +     struct tcfg_gate_entry *next;
>> >> > +     ktime_t close_time, now;
>> >> > +
>> >> > +     spin_lock(&gact->entry_lock);
>> >> > +
>> >> > +     next = rcu_dereference_protected(gact->next_entry,
>> >> > +
>> >> > + lockdep_is_held(&gact->entry_lock));
>> >> > +
>> >> > +     /* cycle start, clear pending bit, clear total octets */
>> >> > +     gact->current_gate_status = next->gate_state ?
>> >> GATE_ACT_GATE_OPEN : 0;
>> >> > +     gact->current_entry_octets = 0;
>> >> > +     gact->current_max_octets = next->maxoctets;
>> >> > +
>> >> > +     gact->current_close_time = ktime_add_ns(gact-
>> >current_close_time,
>> >> > +                                             next->interval);
>> >> > +
>> >> > +     close_time = gact->current_close_time;
>> >> > +
>> >> > +     if (list_is_last(&next->list, &p->entries))
>> >> > +             next = list_first_entry(&p->entries,
>> >> > +                                     struct tcfg_gate_entry, list);
>> >> > +     else
>> >> > +             next = list_next_entry(next, list);
>> >> > +
>> >> > +     now = gate_get_time(gact);
>> >> > +
>> >> > +     if (ktime_after(now, close_time)) {
>> >> > +             ktime_t cycle, base;
>> >> > +             u64 n;
>> >> > +
>> >> > +             cycle = p->tcfg_cycletime;
>> >> > +             base = ns_to_ktime(p->tcfg_basetime);
>> >> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
>> >> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
>> >> > +     }
>> >> > +
>> >> > +     rcu_assign_pointer(gact->next_entry, next);
>> >> > +     spin_unlock(&gact->entry_lock);
>> >>
>> >> I have couple of question about synchronization here:
>> >>
>> >> - Why do you need next_entry to be rcu pointer? It is only assigned
>> >> here with entry_lock protection and in init code before action is
>> >> visible to concurrent users. I don't see any unlocked rcu-protected
>> >> readers here that could benefit from it.
>> >>
>> >> - Why create dedicated entry_lock instead of using already existing
>> >> per- action tcf_lock?
>> >
>> > Will try to use the tcf_lock for verification.
>> > The thoughts came from that the timer period arrived then check
>> > through the list and then update next time would take much more time.
>> > Action function would be busy when traffic. So use a separate lock
>> > here for
>> >
>> >>
>> >> > +
>> >> > +     hrtimer_set_expires(&gact->hitimer, close_time);
>> >> > +
>> >> > +     return HRTIMER_RESTART;
>> >> > +}
>> >> > +
>> >> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
>> >> > +                     struct tcf_result *res) {
>> >> > +     struct tcf_gate *g = to_gate(a);
>> >> > +     struct gate_action *gact;
>> >> > +     int action;
>> >> > +
>> >> > +     tcf_lastuse_update(&g->tcf_tm);
>> >> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
>> >> > +
>> >> > +     action = READ_ONCE(g->tcf_action);
>> >> > +     rcu_read_lock();
>> >>
>> >> Action fastpath is already rcu read lock protected, you don't need to
>> >> manually obtain it.
>> >
>> > Will be removed.
>> >
>> >>
>> >> > +     gact = rcu_dereference_bh(g->actg);
>> >> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {
>> >>
>> >> Can't current_gate_status be concurrently modified by timer callback?
>> >> This function doesn't use entry_lock to synchronize with timer.
>> >
>> > Will try tcf_lock either.
>> >
>> >>
>> >> > +             rcu_read_unlock();
>> >> > +             return action;
>> >> > +     }
>> >> > +
>> >> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
>> >>
>> >> ...and here
>> >>
>> >> > +             goto drop;
>> >> > +
>> >> > +     if (gact->current_max_octets >= 0) {
>> >> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
>> >> > +             if (gact->current_entry_octets >
>> >> > + gact->current_max_octets) {
>> >>
>> >> here also.
>> >>
>> >> > +
>> >> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
>> >>
>> >> Please use tcf_action_inc_overlimit_qstats() and other wrappers for
>> stats.
>> >> Otherwise it will crash if user passes
>> TCA_ACT_FLAGS_NO_PERCPU_STATS
>> >> flag.
>> >
>> > The tcf_action_inc_overlimit_qstats() can't show limit counts in tc show
>> command. Is there anything need to do?
>> 
>> What do you mean? Internally tcf_action_inc_overlimit_qstats() just calls
>> qstats_overlimit_inc, if cpu_qstats percpu counter is not NULL:
>> 
>> 
>>         if (likely(a->cpu_qstats)) {
>>                 qstats_overlimit_inc(this_cpu_ptr(a->cpu_qstats));
>>                 return;
>>         }
>> 
>> Is there a subtle bug somewhere in this function?
>
> Sorry, I updated using the tcf_action_*, and the counting is ok. I moved back to the qstats_overlimit_inc() because tcf_action_* () include the spin_lock(&a->tcfa_lock). 
> I would update to  tcf_action_* () increate. 

BTW if you end up with synchronizing fastpath with tcfa_lock, then you
don't need to use tcf_action_*stats() helpers and percpu counters (they
will only slow down action init and increase memory usage without
providing any improvements for parallelism). Instead, you can just
directly change the tcf_{q|b}stats while holding the tcfa_lock. Check
pedit for example of such action.

>
>> 
>> >
>> > Br,
>> > Po Liu
>
> Thanks a lot.
>
> Br,
> Po Liu

On Thu 23 Apr 2020 at 12:15, Po Liu <po.liu@nxp.com> wrote:
> Hi Vlad Buslov,
>
>> > >> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer)
>> {
>> > >> > +     struct gate_action *gact = container_of(timer, struct
>> gate_action,
>> > >> > +                                             hitimer);
>> > >> > +     struct tcf_gate_params *p = get_gate_param(gact);
>> > >> > +     struct tcfg_gate_entry *next;
>> > >> > +     ktime_t close_time, now;
>> > >> > +
>> > >> > +     spin_lock(&gact->entry_lock);
>> > >> > +
>> > >> > +     next = rcu_dereference_protected(gact->next_entry,
>> > >> > +
>> > >> > + lockdep_is_held(&gact->entry_lock));
>> > >> > +
>> > >> > +     /* cycle start, clear pending bit, clear total octets */
>> > >> > +     gact->current_gate_status = next->gate_state ?
>> > >> GATE_ACT_GATE_OPEN : 0;
>> > >> > +     gact->current_entry_octets = 0;
>> > >> > +     gact->current_max_octets = next->maxoctets;
>> > >> > +
>> > >> > +     gact->current_close_time = ktime_add_ns(gact-
>> > >current_close_time,
>> > >> > +                                             next->interval);
>> > >> > +
>> > >> > +     close_time = gact->current_close_time;
>> > >> > +
>> > >> > +     if (list_is_last(&next->list, &p->entries))
>> > >> > +             next = list_first_entry(&p->entries,
>> > >> > +                                     struct tcfg_gate_entry, list);
>> > >> > +     else
>> > >> > +             next = list_next_entry(next, list);
>> > >> > +
>> > >> > +     now = gate_get_time(gact);
>> > >> > +
>> > >> > +     if (ktime_after(now, close_time)) {
>> > >> > +             ktime_t cycle, base;
>> > >> > +             u64 n;
>> > >> > +
>> > >> > +             cycle = p->tcfg_cycletime;
>> > >> > +             base = ns_to_ktime(p->tcfg_basetime);
>> > >> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
>> > >> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
>> > >> > +     }
>> > >> > +
>> > >> > +     rcu_assign_pointer(gact->next_entry, next);
>> > >> > +     spin_unlock(&gact->entry_lock);
>> > >>
>> > >> I have couple of question about synchronization here:
>> > >>
>> > >> - Why do you need next_entry to be rcu pointer? It is only assigned
>> > >> here with entry_lock protection and in init code before action is
>> > >> visible to concurrent users. I don't see any unlocked rcu-protected
>> > >> readers here that could benefit from it.
>> > >>
>> > >> - Why create dedicated entry_lock instead of using already existing
>> > >> per- action tcf_lock?
>> > >
>> > > Will try to use the tcf_lock for verification.
>
> I think I added entry_lock was that I can't get the tc_action common parameter in this  timer function. If I insist to use the tcf_lock, I have to move the hrtimer to struct tcf_gate which has tc_action common.
> What do you think?

Well, if you use tcf_lock instead of rcu to sync with fastpath, the you
don't need to implement struct gate_action as standalone object pointed
to by rcu pointer from base structure that includes tc_action common.
All the necessary data can be included in tcf_gate structure directly
and used from both timer and action fastpath. See pedit for example of
action that doesn't use rcu for fastpath.

>
>> > > The thoughts came from that the timer period arrived then check
>> > > through the list and then update next time would take much more
>> time.
>> > > Action function would be busy when traffic. So use a separate lock
>> > > here for
>> > >
>> > >>
>> > >> > +
>> > >> > +     hrtimer_set_expires(&gact->hitimer, close_time);
>> > >> > +
>> > >> > +     return HRTIMER_RESTART;
>> > >> > +}
>> > >> > +
>> > >> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
>> > >> > +                     struct tcf_result *res) {
>> > >> > +     struct tcf_gate *g = to_gate(a);
>> > >> > +     struct gate_action *gact;
>> > >> > +     int action;
>> > >> > +
>> > >> > +     tcf_lastuse_update(&g->tcf_tm);
>> > >> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
>> > >> > +
>> > >> > +     action = READ_ONCE(g->tcf_action);
>> > >> > +     rcu_read_lock();
>> > >>
>> > >> Action fastpath is already rcu read lock protected, you don't need
>> > >> to manually obtain it.
>> > >
>> > > Will be removed.
>> > >
>> > >>
>> > >> > +     gact = rcu_dereference_bh(g->actg);
>> > >> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING))
>> > >> > + {
>> > >>
>> > >> Can't current_gate_status be concurrently modified by timer callback?
>> > >> This function doesn't use entry_lock to synchronize with timer.
>> > >
>> > > Will try tcf_lock either.
>> > >
>> > >>
>> > >> > +             rcu_read_unlock();
>> > >> > +             return action;
>> > >> > +     }
>> > >> > +
>> > >> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
>> > >>
>> > >> ...and here
>> > >>
>> > >> > +             goto drop;
>> > >> > +
>> > >> > +     if (gact->current_max_octets >= 0) {
>> > >> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
>> > >> > +             if (gact->current_entry_octets >
>> > >> > + gact->current_max_octets) {
>> > >>
>> > >> here also.
>> > >>
>> > >> > +
>> > >> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
>> > >>
>> > >> Please use tcf_action_inc_overlimit_qstats() and other wrappers for
>> > stats.
>> > >> Otherwise it will crash if user passes
>> > TCA_ACT_FLAGS_NO_PERCPU_STATS
>> > >> flag.
>> > >
>> > > The tcf_action_inc_overlimit_qstats() can't show limit counts in tc
>> > > show
>> > command. Is there anything need to do?
>> >
>> > What do you mean? Internally tcf_action_inc_overlimit_qstats() just
>> > calls qstats_overlimit_inc, if cpu_qstats percpu counter is not NULL:
>> >
>> >
>> >         if (likely(a->cpu_qstats)) {
>> >                 qstats_overlimit_inc(this_cpu_ptr(a->cpu_qstats));
>> >                 return;
>> >         }
>> >
>> > Is there a subtle bug somewhere in this function?
>> 
>> Sorry, I updated using the tcf_action_*, and the counting is ok. I moved
>> back to the qstats_overlimit_inc() because tcf_action_* () include the
>> spin_lock(&a->tcfa_lock).
>> I would update to  tcf_action_* () increate.
>> 
>> >
>> > >
>> > > Br,
>> > > Po Liu
>> 
>> Thanks a lot.
>> 
>> Br,
>> Po Liu
>
> Thanks a lot.
>
> Br,
> Po Liu

Po Liu <Po.Liu@nxp.com> writes:

> Introduce a ingress frame gate control flow action.
> Tc gate action does the work like this:
> Assume there is a gate allow specified ingress frames can be passed at
> specific time slot, and be dropped at specific time slot. Tc filter
> chooses the ingress frames, and tc gate action would specify what slot
> does these frames can be passed to device and what time slot would be
> dropped.
> Tc gate action would provide an entry list to tell how much time gate
> keep open and how much time gate keep state close. Gate action also
> assign a start time to tell when the entry list start. Then driver would
> repeat the gate entry list cyclically.
> For the software simulation, gate action requires the user assign a time
> clock type.
>
> Below is the setting example in user space. Tc filter a stream source ip
> address is 192.168.0.20 and gate action own two time slots. One is last
> 200ms gate open let frame pass another is last 100ms gate close let
> frames dropped. When the frames have passed total frames over 8000000
> bytes, frames will be dropped in one 200000000ns time slot.
>
>> tc qdisc add dev eth0 ingress
>
>> tc filter add dev eth0 parent ffff: protocol ip \
> 	   flower src_ip 192.168.0.20 \
> 	   action gate index 2 clockid CLOCK_TAI \
> 	   sched-entry open 200000000 -1 8000000 \
> 	   sched-entry close 100000000 -1 -1

From the insight that Vladimir gave, it really makes it easier for me to
understand if you added these filters and actions in two steps. The
first, you would add the "time based" actions and the second you would
plug the filters into the actions. And I think this would match real
world usage better.

Another small usability improvement is to make the "extra" parameters to
'sched-entry close' optional, if packets that arrive during a closed
gate are dropped, those parameters don't make much sense.

>
>> tc chain del dev eth0 ingress chain 0
>
> "sched-entry" follow the name taprio style. Gate state is
> "open"/"close". Follow with period nanosecond. Then next item is internal
> priority value means which ingress queue should put. "-1" means
> wildcard. The last value optional specifies the maximum number of
> MSDU octets that are permitted to pass the gate during the specified
> time interval.
> Base-time is not set will be 0 as default, as result start time would
> be ((N + 1) * cycletime) which is the minimal of future time.
>
> Below example shows filtering a stream with destination mac address is
> 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The gate
> action would run with one close time slot which means always keep close.
> The time cycle is total 200000000ns. The base-time would calculate by:
>
>  1357000000000 + (N + 1) * cycletime
>
> When the total value is the future time, it will be the start time.
> The cycletime here would be 200000000ns for this case.
>
>> tc filter add dev eth0 parent ffff:  protocol ip \
> 	   flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
> 	   action gate index 12 base-time 1357000000000 \
> 	   sched-entry close 200000000 -1 -1 \
> 	   clockid CLOCK_TAI
>
> Signed-off-by: Po Liu <Po.Liu@nxp.com>
> ---
>  include/net/tc_act/tc_gate.h        |  54 +++
>  include/uapi/linux/pkt_cls.h        |   1 +
>  include/uapi/linux/tc_act/tc_gate.h |  47 ++
>  net/sched/Kconfig                   |  13 +
>  net/sched/Makefile                  |   1 +
>  net/sched/act_gate.c                | 647 ++++++++++++++++++++++++++++
>  6 files changed, 763 insertions(+)
>  create mode 100644 include/net/tc_act/tc_gate.h
>  create mode 100644 include/uapi/linux/tc_act/tc_gate.h
>  create mode 100644 net/sched/act_gate.c
>
> diff --git a/include/net/tc_act/tc_gate.h b/include/net/tc_act/tc_gate.h
> new file mode 100644
> index 000000000000..b0ace55b2aaa
> --- /dev/null
> +++ b/include/net/tc_act/tc_gate.h
> @@ -0,0 +1,54 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright 2020 NXP */
> +
> +#ifndef __NET_TC_GATE_H
> +#define __NET_TC_GATE_H
> +
> +#include <net/act_api.h>
> +#include <linux/tc_act/tc_gate.h>
> +
> +struct tcfg_gate_entry {
> +	int			index;
> +	u8			gate_state;
> +	u32			interval;
> +	s32			ipv;
> +	s32			maxoctets;
> +	struct list_head	list;
> +};
> +
> +struct tcf_gate_params {
> +	s32			tcfg_priority;
> +	u64			tcfg_basetime;
> +	u64			tcfg_cycletime;
> +	u64			tcfg_cycletime_ext;
> +	u32			tcfg_flags;
> +	s32			tcfg_clockid;
> +	size_t			num_entries;
> +	struct list_head	entries;
> +};
> +
> +#define GATE_ACT_GATE_OPEN	BIT(0)
> +#define GATE_ACT_PENDING	BIT(1)
> +struct gate_action {
> +	struct tcf_gate_params param;
> +	spinlock_t entry_lock;
> +	u8 current_gate_status;
> +	ktime_t current_close_time;
> +	u32 current_entry_octets;
> +	s32 current_max_octets;
> +	struct tcfg_gate_entry __rcu *next_entry;
> +	struct hrtimer hitimer;
> +	enum tk_offsets tk_offset;
> +	struct rcu_head rcu;
> +};
> +
> +struct tcf_gate {
> +	struct tc_action		common;
> +	struct gate_action __rcu	*actg;
> +};
> +#define to_gate(a) ((struct tcf_gate *)a)
> +
> +#define get_gate_param(act) ((struct tcf_gate_params *)act)
> +#define get_gate_action(p) ((struct gate_action *)p)
> +
> +#endif
> diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
> index 9f06d29cab70..fc672b232437 100644
> --- a/include/uapi/linux/pkt_cls.h
> +++ b/include/uapi/linux/pkt_cls.h
> @@ -134,6 +134,7 @@ enum tca_id {
>  	TCA_ID_CTINFO,
>  	TCA_ID_MPLS,
>  	TCA_ID_CT,
> +	TCA_ID_GATE,
>  	/* other actions go here */
>  	__TCA_ID_MAX = 255
>  };
> diff --git a/include/uapi/linux/tc_act/tc_gate.h b/include/uapi/linux/tc_act/tc_gate.h
> new file mode 100644
> index 000000000000..f214b3a6d44f
> --- /dev/null
> +++ b/include/uapi/linux/tc_act/tc_gate.h
> @@ -0,0 +1,47 @@
> +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> +/* Copyright 2020 NXP */
> +
> +#ifndef __LINUX_TC_GATE_H
> +#define __LINUX_TC_GATE_H
> +
> +#include <linux/pkt_cls.h>
> +
> +struct tc_gate {
> +	tc_gen;
> +};
> +
> +enum {
> +	TCA_GATE_ENTRY_UNSPEC,
> +	TCA_GATE_ENTRY_INDEX,
> +	TCA_GATE_ENTRY_GATE,
> +	TCA_GATE_ENTRY_INTERVAL,
> +	TCA_GATE_ENTRY_IPV,
> +	TCA_GATE_ENTRY_MAX_OCTETS,
> +	__TCA_GATE_ENTRY_MAX,
> +};
> +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
> +
> +enum {
> +	TCA_GATE_ONE_ENTRY_UNSPEC,
> +	TCA_GATE_ONE_ENTRY,
> +	__TCA_GATE_ONE_ENTRY_MAX,
> +};
> +#define TCA_GATE_ONE_ENTRY_MAX (__TCA_GATE_ONE_ENTRY_MAX - 1)
> +
> +enum {
> +	TCA_GATE_UNSPEC,
> +	TCA_GATE_TM,
> +	TCA_GATE_PARMS,
> +	TCA_GATE_PAD,
> +	TCA_GATE_PRIORITY,
> +	TCA_GATE_ENTRY_LIST,
> +	TCA_GATE_BASE_TIME,
> +	TCA_GATE_CYCLE_TIME,
> +	TCA_GATE_CYCLE_TIME_EXT,
> +	TCA_GATE_FLAGS,
> +	TCA_GATE_CLOCKID,
> +	__TCA_GATE_MAX,
> +};
> +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
> +
> +#endif
> diff --git a/net/sched/Kconfig b/net/sched/Kconfig
> index bfbefb7bff9d..1314549c7567 100644
> --- a/net/sched/Kconfig
> +++ b/net/sched/Kconfig
> @@ -981,6 +981,19 @@ config NET_ACT_CT
>  	  To compile this code as a module, choose M here: the
>  	  module will be called act_ct.
>  
> +config NET_ACT_GATE
> +	tristate "Frame gate entry list control tc action"
> +	depends on NET_CLS_ACT
> +	help
> +	  Say Y here to allow to control the ingress flow to be passed at
> +	  specific time slot and be dropped at other specific time slot by
> +	  the gate entry list. The manipulation will simulate the IEEE
> +	  802.1Qci stream gate control behavior.
> +
> +	  If unsure, say N.
> +	  To compile this code as a module, choose M here: the
> +	  module will be called act_gate.
> +
>  config NET_IFE_SKBMARK
>  	tristate "Support to encoding decoding skb mark on IFE action"
>  	depends on NET_ACT_IFE
> diff --git a/net/sched/Makefile b/net/sched/Makefile
> index 31c367a6cd09..66bbf9a98f9e 100644
> --- a/net/sched/Makefile
> +++ b/net/sched/Makefile
> @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)	+= act_meta_skbprio.o
>  obj-$(CONFIG_NET_IFE_SKBTCINDEX)	+= act_meta_skbtcindex.o
>  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
>  obj-$(CONFIG_NET_ACT_CT)	+= act_ct.o
> +obj-$(CONFIG_NET_ACT_GATE)	+= act_gate.o
>  obj-$(CONFIG_NET_SCH_FIFO)	+= sch_fifo.o
>  obj-$(CONFIG_NET_SCH_CBQ)	+= sch_cbq.o
>  obj-$(CONFIG_NET_SCH_HTB)	+= sch_htb.o
> diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c
> new file mode 100644
> index 000000000000..e932f402b4f1
> --- /dev/null
> +++ b/net/sched/act_gate.c
> @@ -0,0 +1,647 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* Copyright 2020 NXP */
> +
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/string.h>
> +#include <linux/errno.h>
> +#include <linux/skbuff.h>
> +#include <linux/rtnetlink.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <net/act_api.h>
> +#include <net/netlink.h>
> +#include <net/pkt_cls.h>
> +#include <net/tc_act/tc_gate.h>
> +
> +static unsigned int gate_net_id;
> +static struct tc_action_ops act_gate_ops;
> +
> +static ktime_t gate_get_time(struct gate_action *gact)
> +{
> +	ktime_t mono = ktime_get();
> +
> +	switch (gact->tk_offset) {
> +	case TK_OFFS_MAX:
> +		return mono;
> +	default:
> +		return ktime_mono_to_any(mono, gact->tk_offset);
> +	}
> +
> +	return KTIME_MAX;
> +}
> +
> +static int gate_get_start_time(struct gate_action *gact, ktime_t *start)
> +{
> +	struct tcf_gate_params *param = get_gate_param(gact);
> +	ktime_t now, base, cycle;
> +	u64 n;
> +
> +	base = ns_to_ktime(param->tcfg_basetime);
> +	now = gate_get_time(gact);
> +
> +	if (ktime_after(base, now)) {
> +		*start = base;
> +		return 0;
> +	}
> +
> +	cycle = param->tcfg_cycletime;
> +
> +	/* cycle time should not be zero */
> +	if (WARN_ON(!cycle))
> +		return -EFAULT;
> +
> +	n = div64_u64(ktime_sub_ns(now, base), cycle);
> +	*start = ktime_add_ns(base, (n + 1) * cycle);
> +	return 0;
> +}
> +
> +static void gate_start_timer(struct gate_action *gact, ktime_t start)
> +{
> +	ktime_t expires;
> +
> +	expires = hrtimer_get_expires(&gact->hitimer);
> +	if (expires == 0)
> +		expires = KTIME_MAX;
> +
> +	start = min_t(ktime_t, start, expires);
> +
> +	hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS);
> +}
> +
> +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer)
> +{
> +	struct gate_action *gact = container_of(timer, struct gate_action,
> +						hitimer);
> +	struct tcf_gate_params *p = get_gate_param(gact);
> +	struct tcfg_gate_entry *next;
> +	ktime_t close_time, now;
> +
> +	spin_lock(&gact->entry_lock);
> +
> +	next = rcu_dereference_protected(gact->next_entry,
> +					 lockdep_is_held(&gact->entry_lock));
> +
> +	/* cycle start, clear pending bit, clear total octets */
> +	gact->current_gate_status = next->gate_state ? GATE_ACT_GATE_OPEN : 0;
> +	gact->current_entry_octets = 0;
> +	gact->current_max_octets = next->maxoctets;
> +
> +	gact->current_close_time = ktime_add_ns(gact->current_close_time,
> +						next->interval);
> +
> +	close_time = gact->current_close_time;
> +
> +	if (list_is_last(&next->list, &p->entries))
> +		next = list_first_entry(&p->entries,
> +					struct tcfg_gate_entry, list);
> +	else
> +		next = list_next_entry(next, list);
> +
> +	now = gate_get_time(gact);
> +
> +	if (ktime_after(now, close_time)) {
> +		ktime_t cycle, base;
> +		u64 n;
> +
> +		cycle = p->tcfg_cycletime;
> +		base = ns_to_ktime(p->tcfg_basetime);
> +		n = div64_u64(ktime_sub_ns(now, base), cycle);
> +		close_time = ktime_add_ns(base, (n + 1) * cycle);
> +	}
> +
> +	rcu_assign_pointer(gact->next_entry, next);
> +	spin_unlock(&gact->entry_lock);
> +
> +	hrtimer_set_expires(&gact->hitimer, close_time);
> +
> +	return HRTIMER_RESTART;
> +}
> +
> +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
> +			struct tcf_result *res)
> +{
> +	struct tcf_gate *g = to_gate(a);
> +	struct gate_action *gact;
> +	int action;
> +
> +	tcf_lastuse_update(&g->tcf_tm);
> +	bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
> +
> +	action = READ_ONCE(g->tcf_action);
> +	rcu_read_lock();
> +	gact = rcu_dereference_bh(g->actg);
> +	if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {
> +		rcu_read_unlock();
> +		return action;
> +	}
> +
> +	if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
> +		goto drop;
> +
> +	if (gact->current_max_octets >= 0) {
> +		gact->current_entry_octets += qdisc_pkt_len(skb);
> +		if (gact->current_entry_octets > gact->current_max_octets) {
> +			qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
> +			goto drop;
> +		}
> +	}
> +	rcu_read_unlock();
> +
> +	return action;
> +drop:
> +	rcu_read_unlock();
> +	qstats_drop_inc(this_cpu_ptr(g->common.cpu_qstats));
> +	return TC_ACT_SHOT;
> +}
> +
> +static const struct nla_policy entry_policy[TCA_GATE_ENTRY_MAX + 1] = {
> +	[TCA_GATE_ENTRY_INDEX]		= { .type = NLA_U32 },
> +	[TCA_GATE_ENTRY_GATE]		= { .type = NLA_FLAG },
> +	[TCA_GATE_ENTRY_INTERVAL]	= { .type = NLA_U32 },
> +	[TCA_GATE_ENTRY_IPV]		= { .type = NLA_S32 },
> +	[TCA_GATE_ENTRY_MAX_OCTETS]	= { .type = NLA_S32 },
> +};
> +
> +static const struct nla_policy gate_policy[TCA_GATE_MAX + 1] = {
> +	[TCA_GATE_PARMS]		= { .len = sizeof(struct tc_gate),
> +					    .type = NLA_EXACT_LEN },
> +	[TCA_GATE_PRIORITY]		= { .type = NLA_S32 },
> +	[TCA_GATE_ENTRY_LIST]		= { .type = NLA_NESTED },
> +	[TCA_GATE_BASE_TIME]		= { .type = NLA_U64 },
> +	[TCA_GATE_CYCLE_TIME]		= { .type = NLA_U64 },
> +	[TCA_GATE_CYCLE_TIME_EXT]	= { .type = NLA_U64 },
> +	[TCA_GATE_FLAGS]		= { .type = NLA_U32 },
> +	[TCA_GATE_CLOCKID]		= { .type = NLA_S32 },
> +};
> +
> +static int fill_gate_entry(struct nlattr **tb, struct tcfg_gate_entry *entry,
> +			   struct netlink_ext_ack *extack)
> +{
> +	u32 interval = 0;
> +
> +	entry->gate_state = nla_get_flag(tb[TCA_GATE_ENTRY_GATE]);
> +
> +	if (tb[TCA_GATE_ENTRY_INTERVAL])
> +		interval = nla_get_u32(tb[TCA_GATE_ENTRY_INTERVAL]);
> +
> +	if (interval == 0) {
> +		NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
> +		return -EINVAL;
> +	}
> +
> +	entry->interval = interval;
> +
> +	if (tb[TCA_GATE_ENTRY_IPV])
> +		entry->ipv = nla_get_s32(tb[TCA_GATE_ENTRY_IPV]);
> +	else
> +		entry->ipv = -1;
> +
> +	if (tb[TCA_GATE_ENTRY_MAX_OCTETS])
> +		entry->maxoctets = nla_get_s32(tb[TCA_GATE_ENTRY_MAX_OCTETS]);
> +	else
> +		entry->maxoctets = -1;
> +
> +	return 0;
> +}
> +
> +static int parse_gate_entry(struct nlattr *n, struct  tcfg_gate_entry *entry,
> +			    int index, struct netlink_ext_ack *extack)
> +{
> +	struct nlattr *tb[TCA_GATE_ENTRY_MAX + 1] = { };
> +	int err;
> +
> +	err = nla_parse_nested(tb, TCA_GATE_ENTRY_MAX, n, entry_policy, extack);
> +	if (err < 0) {
> +		NL_SET_ERR_MSG(extack, "Could not parse nested entry");
> +		return -EINVAL;
> +	}
> +
> +	entry->index = index;
> +
> +	return fill_gate_entry(tb, entry, extack);
> +}
> +
> +static int parse_gate_list(struct nlattr *list_attr,
> +			   struct tcf_gate_params *sched,
> +			   struct netlink_ext_ack *extack)
> +{
> +	struct tcfg_gate_entry *entry, *e;
> +	struct nlattr *n;
> +	int err, rem;
> +	int i = 0;
> +
> +	if (!list_attr)
> +		return -EINVAL;
> +
> +	nla_for_each_nested(n, list_attr, rem) {
> +		if (nla_type(n) != TCA_GATE_ONE_ENTRY) {
> +			NL_SET_ERR_MSG(extack, "Attribute isn't type 'entry'");
> +			continue;
> +		}
> +
> +		entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> +		if (!entry) {
> +			NL_SET_ERR_MSG(extack, "Not enough memory for entry");
> +			err = -ENOMEM;
> +			goto release_list;
> +		}
> +
> +		err = parse_gate_entry(n, entry, i, extack);
> +		if (err < 0) {
> +			kfree(entry);
> +			goto release_list;
> +		}
> +
> +		list_add_tail(&entry->list, &sched->entries);
> +		i++;
> +	}
> +
> +	sched->num_entries = i;
> +
> +	return i;
> +
> +release_list:
> +	list_for_each_entry_safe(entry, e, &sched->entries, list) {
> +		list_del(&entry->list);
> +		kfree(entry);
> +	}
> +
> +	return err;
> +}
> +
> +static int tcf_gate_init(struct net *net, struct nlattr *nla,
> +			 struct nlattr *est, struct tc_action **a,
> +			 int ovr, int bind, bool rtnl_held,
> +			 struct tcf_proto *tp, u32 flags,
> +			 struct netlink_ext_ack *extack)
> +{
> +	struct tc_action_net *tn = net_generic(net, gate_net_id);
> +	enum tk_offsets tk_offset = TK_OFFS_TAI;
> +	struct nlattr *tb[TCA_GATE_MAX + 1];
> +	struct tcf_chain *goto_ch = NULL;
> +	struct tcfg_gate_entry *next;
> +	struct tcf_gate_params *p;
> +	struct gate_action *gact;
> +	s32 clockid = CLOCK_TAI;
> +	struct tc_gate *parm;
> +	struct tcf_gate *g;
> +	int ret = 0, err;
> +	u64 basetime = 0;
> +	u32 gflags = 0;
> +	s32 prio = -1;
> +	ktime_t start;
> +	u32 index;
> +
> +	if (!nla)
> +		return -EINVAL;
> +
> +	err = nla_parse_nested(tb, TCA_GATE_MAX, nla, gate_policy, extack);
> +	if (err < 0)
> +		return err;
> +
> +	if (!tb[TCA_GATE_PARMS])
> +		return -EINVAL;
> +	parm = nla_data(tb[TCA_GATE_PARMS]);
> +	index = parm->index;
> +	err = tcf_idr_check_alloc(tn, &index, a, bind);
> +	if (err < 0)
> +		return err;
> +
> +	if (err && bind)
> +		return 0;
> +
> +	if (!err) {
> +		ret = tcf_idr_create_from_flags(tn, index, est, a,
> +						&act_gate_ops, bind, flags);
> +		if (ret) {
> +			tcf_idr_cleanup(tn, index);
> +			return ret;
> +		}
> +
> +		ret = ACT_P_CREATED;
> +	} else if (!ovr) {
> +		tcf_idr_release(*a, bind);
> +		return -EEXIST;
> +	}
> +
> +	if (tb[TCA_GATE_PRIORITY])
> +		prio = nla_get_s32(tb[TCA_GATE_PRIORITY]);
> +
> +	if (tb[TCA_GATE_BASE_TIME])
> +		basetime = nla_get_u64(tb[TCA_GATE_BASE_TIME]);
> +
> +	if (tb[TCA_GATE_FLAGS])
> +		gflags = nla_get_u32(tb[TCA_GATE_FLAGS]);
> +
> +	if (tb[TCA_GATE_CLOCKID]) {
> +		clockid = nla_get_s32(tb[TCA_GATE_CLOCKID]);
> +		switch (clockid) {
> +		case CLOCK_REALTIME:
> +			tk_offset = TK_OFFS_REAL;
> +			break;
> +		case CLOCK_MONOTONIC:
> +			tk_offset = TK_OFFS_MAX;
> +			break;
> +		case CLOCK_BOOTTIME:
> +			tk_offset = TK_OFFS_BOOT;
> +			break;
> +		case CLOCK_TAI:
> +			tk_offset = TK_OFFS_TAI;
> +			break;
> +		default:
> +			NL_SET_ERR_MSG(extack, "Invalid 'clockid'");
> +			goto release_idr;
> +		}
> +	}
> +
> +	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
> +	if (err < 0)
> +		goto release_idr;
> +
> +	g = to_gate(*a);
> +
> +	gact = kzalloc(sizeof(*gact), GFP_KERNEL);
> +	if (!gact) {
> +		err = -ENOMEM;
> +		goto put_chain;
> +	}
> +
> +	p = get_gate_param(gact);
> +
> +	INIT_LIST_HEAD(&p->entries);
> +	if (tb[TCA_GATE_ENTRY_LIST]) {
> +		err = parse_gate_list(tb[TCA_GATE_ENTRY_LIST], p, extack);
> +		if (err < 0)
> +			goto release_mem;
> +	}
> +
> +	if (tb[TCA_GATE_CYCLE_TIME]) {
> +		p->tcfg_cycletime = nla_get_u64(tb[TCA_GATE_CYCLE_TIME]);
> +	} else {
> +		struct tcfg_gate_entry *entry;
> +		ktime_t cycle = 0;
> +
> +		list_for_each_entry(entry, &p->entries, list)
> +			cycle = ktime_add_ns(cycle, entry->interval);
> +		p->tcfg_cycletime = cycle;
> +	}
> +
> +	if (tb[TCA_GATE_CYCLE_TIME_EXT])
> +		p->tcfg_cycletime_ext =
> +			nla_get_u64(tb[TCA_GATE_CYCLE_TIME_EXT]);
> +
> +	p->tcfg_priority = prio;
> +	p->tcfg_basetime = basetime;
> +	p->tcfg_clockid = clockid;
> +	p->tcfg_flags = gflags;
> +
> +	gact->tk_offset = tk_offset;
> +	spin_lock_init(&gact->entry_lock);
> +	hrtimer_init(&gact->hitimer, clockid, HRTIMER_MODE_ABS);
> +	gact->hitimer.function = gate_timer_func;
> +

One idea that just happened, if you find a way to enable RX timestamping
and can rely that all packets have a timestamp, the code can simplified
a lot. You wouldn't need any hrtimers, and deciding to drop or not
a packet becomes a couple of mathematical operations. Seems worth a
thought.

The real question is: if requiring for the driver to support at least
software RX timestamping is excessive (doesn't seem so to me).


Cheers,

On 22.04.2020 22:28, Vladimir Oltean wrote:
>> >> tc qdisc add dev eth0 ingress
>> >
>> >> tc filter add dev eth0 parent ffff: protocol ip \
>> >           flower src_ip 192.168.0.20 \
>> >           action gate index 2 clockid CLOCK_TAI \
>> >           sched-entry open 200000000 -1 8000000 \
>> >           sched-entry close 100000000 -1 -1
>>
>> First of all, it is a long time since I read the 802.1Qci and when I did
>> it, it was a draft. So please let me know if I'm completly off here.
>>
>> I know you are focusing on the gate control in this patch serie, but I
>> assume that you later will want to do the policing and flow-meter as
>> well. And it could make sense to consider how all of this work
>> toghether.
>>
>> A common use-case for the policing is to have multiple rules pointing at
>> the same policing instance. Maybe you want the sum of the traffic on 2
>> ports to be limited to 100mbit. If you specify such action on the
>> individual rule (like done with the gate), then you can not have two
>> rules pointing at the same policer instance.
>>
>> Long storry short, have you considered if it would be better to do
>> something like:
>>
>>    tc filter add dev eth0 parent ffff: protocol ip \
>>             flower src_ip 192.168.0.20 \
>>             action psfp-id 42
>>
>> And then have some other function to configure the properties of psfp-id
>> 42?
>>
>>
>> /Allan
>>
>
>It is very good that you brought it up though, since in my opinion too
>it is a rather important aspect, and it seems that the fact this
>feature is already designed-in was a bit too subtle.
>
>"psfp-id" is actually his "index" argument.
Ahh.. Thanks for clarifying, I missed this point completly.

On 23.04.2020 10:38, Vinicius Costa Gomes wrote:
>EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
>Po Liu <Po.Liu@nxp.com> writes:
>>> tc filter add dev eth0 parent ffff: protocol ip \
>>          flower src_ip 192.168.0.20 \
>>          action gate index 2 clockid CLOCK_TAI \
>>          sched-entry open 200000000 -1 8000000 \
>>          sched-entry close 100000000 -1 -1
>
>From the insight that Vladimir gave, it really makes it easier for me to
>understand if you added these filters and actions in two steps. The
>first, you would add the "time based" actions and the second you would
>plug the filters into the actions. And I think this would match real
>world usage better.
I agree.

/Allan

Hi Vinicius,


> -----Original Message-----
> From: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Sent: 2020年4月24日 1:38
> To: Po Liu <po.liu@nxp.com>; davem@davemloft.net; linux-
> kernel@vger.kernel.org; netdev@vger.kernel.org
> Cc: Po Liu <po.liu@nxp.com>; Claudiu Manoil <claudiu.manoil@nxp.com>;
> Vladimir Oltean <vladimir.oltean@nxp.com>; Alexandru Marginean
> <alexandru.marginean@nxp.com>; michael.chan@broadcom.com;
> vishal@chelsio.com; saeedm@mellanox.com; leon@kernel.org;
> jiri@mellanox.com; idosch@mellanox.com;
> alexandre.belloni@bootlin.com; UNGLinuxDriver@microchip.com;
> kuba@kernel.org; jhs@mojatatu.com; xiyou.wangcong@gmail.com;
> simon.horman@netronome.com; pablo@netfilter.org;
> moshe@mellanox.com; m-karicheri2@ti.com;
> andre.guedes@linux.intel.com; stephen@networkplumber.org; Po Liu
> <po.liu@nxp.com>
> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow
> action
> 
> Caution: EXT Email
> 
> Po Liu <Po.Liu@nxp.com> writes:
> 
> > Introduce a ingress frame gate control flow action.
> > Tc gate action does the work like this:
> > Assume there is a gate allow specified ingress frames can be passed at
> > specific time slot, and be dropped at specific time slot. Tc filter
> > chooses the ingress frames, and tc gate action would specify what slot
> > does these frames can be passed to device and what time slot would be
> > dropped.
> > Tc gate action would provide an entry list to tell how much time gate
> > keep open and how much time gate keep state close. Gate action also
> > assign a start time to tell when the entry list start. Then driver
> > would repeat the gate entry list cyclically.
> > For the software simulation, gate action requires the user assign a
> > time clock type.
> >
> > Below is the setting example in user space. Tc filter a stream source
> > ip address is 192.168.0.20 and gate action own two time slots. One is
> > last 200ms gate open let frame pass another is last 100ms gate close
> > let frames dropped. When the frames have passed total frames over
> > 8000000 bytes, frames will be dropped in one 200000000ns time slot.
> >
> >> tc qdisc add dev eth0 ingress
> >
> >> tc filter add dev eth0 parent ffff: protocol ip \
> >          flower src_ip 192.168.0.20 \
> >          action gate index 2 clockid CLOCK_TAI \
> >          sched-entry open 200000000 -1 8000000 \
> >          sched-entry close 100000000 -1 -1
> 
> From the insight that Vladimir gave, it really makes it easier for me to
> understand if you added these filters and actions in two steps. The first,
> you would add the "time based" actions and the second you would plug
> the filters into the actions. And I think this would match real world usage
> better.
> 
> Another small usability improvement is to make the "extra" parameters to
> 'sched-entry close' optional, if packets that arrive during a closed gate are
> dropped, those parameters don't make much sense.
> 

This is make sense. Vladmir Oltean also suggest to default value if not set the last two parameters. I would modify it on the user space iproute2 patch.

> >
> >> tc chain del dev eth0 ingress chain 0
> >
> > "sched-entry" follow the name taprio style. Gate state is
> > "open"/"close". Follow with period nanosecond. Then next item is
> > internal priority value means which ingress queue should put. "-1"
> > means wildcard. The last value optional specifies the maximum number
> > of MSDU octets that are permitted to pass the gate during the
> > specified time interval.
> > Base-time is not set will be 0 as default, as result start time would
> > be ((N + 1) * cycletime) which is the minimal of future time.
> >
> > Below example shows filtering a stream with destination mac address is
> > 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The
> > gate action would run with one close time slot which means always keep
> close.
> > The time cycle is total 200000000ns. The base-time would calculate by:
> >
> >  1357000000000 + (N + 1) * cycletime
> >
> > When the total value is the future time, it will be the start time.
> > The cycletime here would be 200000000ns for this case.
> >
> >> tc filter add dev eth0 parent ffff:  protocol ip \
> >          flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
> >          action gate index 12 base-time 1357000000000 \
> >          sched-entry close 200000000 -1 -1 \
> >          clockid CLOCK_TAI
> >
> > Signed-off-by: Po Liu <Po.Liu@nxp.com>
> > ---
> >  include/net/tc_act/tc_gate.h        |  54 +++
> >  include/uapi/linux/pkt_cls.h        |   1 +
> >  include/uapi/linux/tc_act/tc_gate.h |  47 ++
> >  net/sched/Kconfig                   |  13 +
> >  net/sched/Makefile                  |   1 +
> >  net/sched/act_gate.c                | 647 ++++++++++++++++++++++++++++
> >  6 files changed, 763 insertions(+)
> >  create mode 100644 include/net/tc_act/tc_gate.h  create mode 100644
> > include/uapi/linux/tc_act/tc_gate.h
> >  create mode 100644 net/sched/act_gate.c
> >
> > diff --git a/include/net/tc_act/tc_gate.h
> > b/include/net/tc_act/tc_gate.h new file mode 100644 index
> > 000000000000..b0ace55b2aaa
> > --- /dev/null
> > +++ b/include/net/tc_act/tc_gate.h
> > @@ -0,0 +1,54 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > +/* Copyright 2020 NXP */
> > +
> > +#ifndef __NET_TC_GATE_H
> > +#define __NET_TC_GATE_H
> > +
> > +#include <net/act_api.h>
> > +#include <linux/tc_act/tc_gate.h>
> > +
> > +struct tcfg_gate_entry {
> > +     int                     index;
> > +     u8                      gate_state;
> > +     u32                     interval;
> > +     s32                     ipv;
> > +     s32                     maxoctets;
> > +     struct list_head        list;
> > +};
> > +
> > +struct tcf_gate_params {
> > +     s32                     tcfg_priority;
> > +     u64                     tcfg_basetime;
> > +     u64                     tcfg_cycletime;
> > +     u64                     tcfg_cycletime_ext;
> > +     u32                     tcfg_flags;
> > +     s32                     tcfg_clockid;
> > +     size_t                  num_entries;
> > +     struct list_head        entries;
> > +};
> > +
> > +#define GATE_ACT_GATE_OPEN   BIT(0)
> > +#define GATE_ACT_PENDING     BIT(1)
> > +struct gate_action {
> > +     struct tcf_gate_params param;
> > +     spinlock_t entry_lock;
> > +     u8 current_gate_status;
> > +     ktime_t current_close_time;
> > +     u32 current_entry_octets;
> > +     s32 current_max_octets;
> > +     struct tcfg_gate_entry __rcu *next_entry;
> > +     struct hrtimer hitimer;
> > +     enum tk_offsets tk_offset;
> > +     struct rcu_head rcu;
> > +};
> > +
> > +struct tcf_gate {
> > +     struct tc_action                common;
> > +     struct gate_action __rcu        *actg;
> > +};
> > +#define to_gate(a) ((struct tcf_gate *)a)
> > +
> > +#define get_gate_param(act) ((struct tcf_gate_params *)act) #define
> > +get_gate_action(p) ((struct gate_action *)p)
> > +
> > +#endif
> > diff --git a/include/uapi/linux/pkt_cls.h
> > b/include/uapi/linux/pkt_cls.h index 9f06d29cab70..fc672b232437
> 100644
> > --- a/include/uapi/linux/pkt_cls.h
> > +++ b/include/uapi/linux/pkt_cls.h
> > @@ -134,6 +134,7 @@ enum tca_id {
> >       TCA_ID_CTINFO,
> >       TCA_ID_MPLS,
> >       TCA_ID_CT,
> > +     TCA_ID_GATE,
> >       /* other actions go here */
> >       __TCA_ID_MAX = 255
> >  };
> > diff --git a/include/uapi/linux/tc_act/tc_gate.h
> > b/include/uapi/linux/tc_act/tc_gate.h
> > new file mode 100644
> > index 000000000000..f214b3a6d44f
> > --- /dev/null
> > +++ b/include/uapi/linux/tc_act/tc_gate.h
> > @@ -0,0 +1,47 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> > +/* Copyright 2020 NXP */
> > +
> > +#ifndef __LINUX_TC_GATE_H
> > +#define __LINUX_TC_GATE_H
> > +
> > +#include <linux/pkt_cls.h>
> > +
> > +struct tc_gate {
> > +     tc_gen;
> > +};
> > +
> > +enum {
> > +     TCA_GATE_ENTRY_UNSPEC,
> > +     TCA_GATE_ENTRY_INDEX,
> > +     TCA_GATE_ENTRY_GATE,
> > +     TCA_GATE_ENTRY_INTERVAL,
> > +     TCA_GATE_ENTRY_IPV,
> > +     TCA_GATE_ENTRY_MAX_OCTETS,
> > +     __TCA_GATE_ENTRY_MAX,
> > +};
> > +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
> > +
> > +enum {
> > +     TCA_GATE_ONE_ENTRY_UNSPEC,
> > +     TCA_GATE_ONE_ENTRY,
> > +     __TCA_GATE_ONE_ENTRY_MAX,
> > +};
> > +#define TCA_GATE_ONE_ENTRY_MAX (__TCA_GATE_ONE_ENTRY_MAX
> - 1)
> > +
> > +enum {
> > +     TCA_GATE_UNSPEC,
> > +     TCA_GATE_TM,
> > +     TCA_GATE_PARMS,
> > +     TCA_GATE_PAD,
> > +     TCA_GATE_PRIORITY,
> > +     TCA_GATE_ENTRY_LIST,
> > +     TCA_GATE_BASE_TIME,
> > +     TCA_GATE_CYCLE_TIME,
> > +     TCA_GATE_CYCLE_TIME_EXT,
> > +     TCA_GATE_FLAGS,
> > +     TCA_GATE_CLOCKID,
> > +     __TCA_GATE_MAX,
> > +};
> > +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
> > +
> > +#endif
> > diff --git a/net/sched/Kconfig b/net/sched/Kconfig index
> > bfbefb7bff9d..1314549c7567 100644
> > --- a/net/sched/Kconfig
> > +++ b/net/sched/Kconfig
> > @@ -981,6 +981,19 @@ config NET_ACT_CT
> >         To compile this code as a module, choose M here: the
> >         module will be called act_ct.
> >
> > +config NET_ACT_GATE
> > +     tristate "Frame gate entry list control tc action"
> > +     depends on NET_CLS_ACT
> > +     help
> > +       Say Y here to allow to control the ingress flow to be passed at
> > +       specific time slot and be dropped at other specific time slot by
> > +       the gate entry list. The manipulation will simulate the IEEE
> > +       802.1Qci stream gate control behavior.
> > +
> > +       If unsure, say N.
> > +       To compile this code as a module, choose M here: the
> > +       module will be called act_gate.
> > +
> >  config NET_IFE_SKBMARK
> >       tristate "Support to encoding decoding skb mark on IFE action"
> >       depends on NET_ACT_IFE
> > diff --git a/net/sched/Makefile b/net/sched/Makefile index
> > 31c367a6cd09..66bbf9a98f9e 100644
> > --- a/net/sched/Makefile
> > +++ b/net/sched/Makefile
> > @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)       +=
> act_meta_skbprio.o
> >  obj-$(CONFIG_NET_IFE_SKBTCINDEX)     += act_meta_skbtcindex.o
> >  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
> >  obj-$(CONFIG_NET_ACT_CT)     += act_ct.o
> > +obj-$(CONFIG_NET_ACT_GATE)   += act_gate.o
> >  obj-$(CONFIG_NET_SCH_FIFO)   += sch_fifo.o
> >  obj-$(CONFIG_NET_SCH_CBQ)    += sch_cbq.o
> >  obj-$(CONFIG_NET_SCH_HTB)    += sch_htb.o
> > diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c new file mode
> > 100644 index 000000000000..e932f402b4f1
> > --- /dev/null
> > +++ b/net/sched/act_gate.c
> > @@ -0,0 +1,647 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/* Copyright 2020 NXP */
> > +
> > +#include <linux/module.h>
> > +#include <linux/types.h>
> > +#include <linux/kernel.h>
> > +#include <linux/string.h>
> > +#include <linux/errno.h>
> > +#include <linux/skbuff.h>
> > +#include <linux/rtnetlink.h>
> > +#include <linux/init.h>
> > +#include <linux/slab.h>
> > +#include <net/act_api.h>
> > +#include <net/netlink.h>
> > +#include <net/pkt_cls.h>
> > +#include <net/tc_act/tc_gate.h>
> > +
> > +static unsigned int gate_net_id;
> > +static struct tc_action_ops act_gate_ops;
> > +
> > +static ktime_t gate_get_time(struct gate_action *gact) {
> > +     ktime_t mono = ktime_get();
> > +
> > +     switch (gact->tk_offset) {
> > +     case TK_OFFS_MAX:
> > +             return mono;
> > +     default:
> > +             return ktime_mono_to_any(mono, gact->tk_offset);
> > +     }
> > +
> > +     return KTIME_MAX;
> > +}
> > +
> > +static int gate_get_start_time(struct gate_action *gact, ktime_t
> > +*start) {
> > +     struct tcf_gate_params *param = get_gate_param(gact);
> > +     ktime_t now, base, cycle;
> > +     u64 n;
> > +
> > +     base = ns_to_ktime(param->tcfg_basetime);
> > +     now = gate_get_time(gact);
> > +
> > +     if (ktime_after(base, now)) {
> > +             *start = base;
> > +             return 0;
> > +     }
> > +
> > +     cycle = param->tcfg_cycletime;
> > +
> > +     /* cycle time should not be zero */
> > +     if (WARN_ON(!cycle))
> > +             return -EFAULT;
> > +
> > +     n = div64_u64(ktime_sub_ns(now, base), cycle);
> > +     *start = ktime_add_ns(base, (n + 1) * cycle);
> > +     return 0;
> > +}
> > +
> > +static void gate_start_timer(struct gate_action *gact, ktime_t start)
> > +{
> > +     ktime_t expires;
> > +
> > +     expires = hrtimer_get_expires(&gact->hitimer);
> > +     if (expires == 0)
> > +             expires = KTIME_MAX;
> > +
> > +     start = min_t(ktime_t, start, expires);
> > +
> > +     hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS); }
> > +
> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer) {
> > +     struct gate_action *gact = container_of(timer, struct gate_action,
> > +                                             hitimer);
> > +     struct tcf_gate_params *p = get_gate_param(gact);
> > +     struct tcfg_gate_entry *next;
> > +     ktime_t close_time, now;
> > +
> > +     spin_lock(&gact->entry_lock);
> > +
> > +     next = rcu_dereference_protected(gact->next_entry,
> > +
> > + lockdep_is_held(&gact->entry_lock));
> > +
> > +     /* cycle start, clear pending bit, clear total octets */
> > +     gact->current_gate_status = next->gate_state ?
> GATE_ACT_GATE_OPEN : 0;
> > +     gact->current_entry_octets = 0;
> > +     gact->current_max_octets = next->maxoctets;
> > +
> > +     gact->current_close_time = ktime_add_ns(gact->current_close_time,
> > +                                             next->interval);
> > +
> > +     close_time = gact->current_close_time;
> > +
> > +     if (list_is_last(&next->list, &p->entries))
> > +             next = list_first_entry(&p->entries,
> > +                                     struct tcfg_gate_entry, list);
> > +     else
> > +             next = list_next_entry(next, list);
> > +
> > +     now = gate_get_time(gact);
> > +
> > +     if (ktime_after(now, close_time)) {
> > +             ktime_t cycle, base;
> > +             u64 n;
> > +
> > +             cycle = p->tcfg_cycletime;
> > +             base = ns_to_ktime(p->tcfg_basetime);
> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
> > +     }
> > +
> > +     rcu_assign_pointer(gact->next_entry, next);
> > +     spin_unlock(&gact->entry_lock);
> > +
> > +     hrtimer_set_expires(&gact->hitimer, close_time);
> > +
> > +     return HRTIMER_RESTART;
> > +}
> > +
> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
> > +                     struct tcf_result *res) {
> > +     struct tcf_gate *g = to_gate(a);
> > +     struct gate_action *gact;
> > +     int action;
> > +
> > +     tcf_lastuse_update(&g->tcf_tm);
> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
> > +
> > +     action = READ_ONCE(g->tcf_action);
> > +     rcu_read_lock();
> > +     gact = rcu_dereference_bh(g->actg);
> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {
> > +             rcu_read_unlock();
> > +             return action;
> > +     }
> > +
> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
> > +             goto drop;
> > +
> > +     if (gact->current_max_octets >= 0) {
> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
> > +             if (gact->current_entry_octets > gact->current_max_octets) {
> > +                     qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
> > +                     goto drop;
> > +             }
> > +     }
> > +     rcu_read_unlock();
> > +
> > +     return action;
> > +drop:
> > +     rcu_read_unlock();
> > +     qstats_drop_inc(this_cpu_ptr(g->common.cpu_qstats));
> > +     return TC_ACT_SHOT;
> > +}
> > +
> > +static const struct nla_policy entry_policy[TCA_GATE_ENTRY_MAX + 1]
> = {
> > +     [TCA_GATE_ENTRY_INDEX]          = { .type = NLA_U32 },
> > +     [TCA_GATE_ENTRY_GATE]           = { .type = NLA_FLAG },
> > +     [TCA_GATE_ENTRY_INTERVAL]       = { .type = NLA_U32 },
> > +     [TCA_GATE_ENTRY_IPV]            = { .type = NLA_S32 },
> > +     [TCA_GATE_ENTRY_MAX_OCTETS]     = { .type = NLA_S32 },
> > +};
> > +
> > +static const struct nla_policy gate_policy[TCA_GATE_MAX + 1] = {
> > +     [TCA_GATE_PARMS]                = { .len = sizeof(struct tc_gate),
> > +                                         .type = NLA_EXACT_LEN },
> > +     [TCA_GATE_PRIORITY]             = { .type = NLA_S32 },
> > +     [TCA_GATE_ENTRY_LIST]           = { .type = NLA_NESTED },
> > +     [TCA_GATE_BASE_TIME]            = { .type = NLA_U64 },
> > +     [TCA_GATE_CYCLE_TIME]           = { .type = NLA_U64 },
> > +     [TCA_GATE_CYCLE_TIME_EXT]       = { .type = NLA_U64 },
> > +     [TCA_GATE_FLAGS]                = { .type = NLA_U32 },
> > +     [TCA_GATE_CLOCKID]              = { .type = NLA_S32 },
> > +};
> > +
> > +static int fill_gate_entry(struct nlattr **tb, struct tcfg_gate_entry *entry,
> > +                        struct netlink_ext_ack *extack) {
> > +     u32 interval = 0;
> > +
> > +     entry->gate_state = nla_get_flag(tb[TCA_GATE_ENTRY_GATE]);
> > +
> > +     if (tb[TCA_GATE_ENTRY_INTERVAL])
> > +             interval = nla_get_u32(tb[TCA_GATE_ENTRY_INTERVAL]);
> > +
> > +     if (interval == 0) {
> > +             NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
> > +             return -EINVAL;
> > +     }
> > +
> > +     entry->interval = interval;
> > +
> > +     if (tb[TCA_GATE_ENTRY_IPV])
> > +             entry->ipv = nla_get_s32(tb[TCA_GATE_ENTRY_IPV]);
> > +     else
> > +             entry->ipv = -1;
> > +
> > +     if (tb[TCA_GATE_ENTRY_MAX_OCTETS])
> > +             entry->maxoctets =
> nla_get_s32(tb[TCA_GATE_ENTRY_MAX_OCTETS]);
> > +     else
> > +             entry->maxoctets = -1;
> > +
> > +     return 0;
> > +}
> > +
> > +static int parse_gate_entry(struct nlattr *n, struct  tcfg_gate_entry
> *entry,
> > +                         int index, struct netlink_ext_ack *extack) {
> > +     struct nlattr *tb[TCA_GATE_ENTRY_MAX + 1] = { };
> > +     int err;
> > +
> > +     err = nla_parse_nested(tb, TCA_GATE_ENTRY_MAX, n, entry_policy,
> extack);
> > +     if (err < 0) {
> > +             NL_SET_ERR_MSG(extack, "Could not parse nested entry");
> > +             return -EINVAL;
> > +     }
> > +
> > +     entry->index = index;
> > +
> > +     return fill_gate_entry(tb, entry, extack); }
> > +
> > +static int parse_gate_list(struct nlattr *list_attr,
> > +                        struct tcf_gate_params *sched,
> > +                        struct netlink_ext_ack *extack) {
> > +     struct tcfg_gate_entry *entry, *e;
> > +     struct nlattr *n;
> > +     int err, rem;
> > +     int i = 0;
> > +
> > +     if (!list_attr)
> > +             return -EINVAL;
> > +
> > +     nla_for_each_nested(n, list_attr, rem) {
> > +             if (nla_type(n) != TCA_GATE_ONE_ENTRY) {
> > +                     NL_SET_ERR_MSG(extack, "Attribute isn't type 'entry'");
> > +                     continue;
> > +             }
> > +
> > +             entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> > +             if (!entry) {
> > +                     NL_SET_ERR_MSG(extack, "Not enough memory for entry");
> > +                     err = -ENOMEM;
> > +                     goto release_list;
> > +             }
> > +
> > +             err = parse_gate_entry(n, entry, i, extack);
> > +             if (err < 0) {
> > +                     kfree(entry);
> > +                     goto release_list;
> > +             }
> > +
> > +             list_add_tail(&entry->list, &sched->entries);
> > +             i++;
> > +     }
> > +
> > +     sched->num_entries = i;
> > +
> > +     return i;
> > +
> > +release_list:
> > +     list_for_each_entry_safe(entry, e, &sched->entries, list) {
> > +             list_del(&entry->list);
> > +             kfree(entry);
> > +     }
> > +
> > +     return err;
> > +}
> > +
> > +static int tcf_gate_init(struct net *net, struct nlattr *nla,
> > +                      struct nlattr *est, struct tc_action **a,
> > +                      int ovr, int bind, bool rtnl_held,
> > +                      struct tcf_proto *tp, u32 flags,
> > +                      struct netlink_ext_ack *extack) {
> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
> > +     enum tk_offsets tk_offset = TK_OFFS_TAI;
> > +     struct nlattr *tb[TCA_GATE_MAX + 1];
> > +     struct tcf_chain *goto_ch = NULL;
> > +     struct tcfg_gate_entry *next;
> > +     struct tcf_gate_params *p;
> > +     struct gate_action *gact;
> > +     s32 clockid = CLOCK_TAI;
> > +     struct tc_gate *parm;
> > +     struct tcf_gate *g;
> > +     int ret = 0, err;
> > +     u64 basetime = 0;
> > +     u32 gflags = 0;
> > +     s32 prio = -1;
> > +     ktime_t start;
> > +     u32 index;
> > +
> > +     if (!nla)
> > +             return -EINVAL;
> > +
> > +     err = nla_parse_nested(tb, TCA_GATE_MAX, nla, gate_policy, extack);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     if (!tb[TCA_GATE_PARMS])
> > +             return -EINVAL;
> > +     parm = nla_data(tb[TCA_GATE_PARMS]);
> > +     index = parm->index;
> > +     err = tcf_idr_check_alloc(tn, &index, a, bind);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     if (err && bind)
> > +             return 0;
> > +
> > +     if (!err) {
> > +             ret = tcf_idr_create_from_flags(tn, index, est, a,
> > +                                             &act_gate_ops, bind, flags);
> > +             if (ret) {
> > +                     tcf_idr_cleanup(tn, index);
> > +                     return ret;
> > +             }
> > +
> > +             ret = ACT_P_CREATED;
> > +     } else if (!ovr) {
> > +             tcf_idr_release(*a, bind);
> > +             return -EEXIST;
> > +     }
> > +
> > +     if (tb[TCA_GATE_PRIORITY])
> > +             prio = nla_get_s32(tb[TCA_GATE_PRIORITY]);
> > +
> > +     if (tb[TCA_GATE_BASE_TIME])
> > +             basetime = nla_get_u64(tb[TCA_GATE_BASE_TIME]);
> > +
> > +     if (tb[TCA_GATE_FLAGS])
> > +             gflags = nla_get_u32(tb[TCA_GATE_FLAGS]);
> > +
> > +     if (tb[TCA_GATE_CLOCKID]) {
> > +             clockid = nla_get_s32(tb[TCA_GATE_CLOCKID]);
> > +             switch (clockid) {
> > +             case CLOCK_REALTIME:
> > +                     tk_offset = TK_OFFS_REAL;
> > +                     break;
> > +             case CLOCK_MONOTONIC:
> > +                     tk_offset = TK_OFFS_MAX;
> > +                     break;
> > +             case CLOCK_BOOTTIME:
> > +                     tk_offset = TK_OFFS_BOOT;
> > +                     break;
> > +             case CLOCK_TAI:
> > +                     tk_offset = TK_OFFS_TAI;
> > +                     break;
> > +             default:
> > +                     NL_SET_ERR_MSG(extack, "Invalid 'clockid'");
> > +                     goto release_idr;
> > +             }
> > +     }
> > +
> > +     err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
> > +     if (err < 0)
> > +             goto release_idr;
> > +
> > +     g = to_gate(*a);
> > +
> > +     gact = kzalloc(sizeof(*gact), GFP_KERNEL);
> > +     if (!gact) {
> > +             err = -ENOMEM;
> > +             goto put_chain;
> > +     }
> > +
> > +     p = get_gate_param(gact);
> > +
> > +     INIT_LIST_HEAD(&p->entries);
> > +     if (tb[TCA_GATE_ENTRY_LIST]) {
> > +             err = parse_gate_list(tb[TCA_GATE_ENTRY_LIST], p, extack);
> > +             if (err < 0)
> > +                     goto release_mem;
> > +     }
> > +
> > +     if (tb[TCA_GATE_CYCLE_TIME]) {
> > +             p->tcfg_cycletime = nla_get_u64(tb[TCA_GATE_CYCLE_TIME]);
> > +     } else {
> > +             struct tcfg_gate_entry *entry;
> > +             ktime_t cycle = 0;
> > +
> > +             list_for_each_entry(entry, &p->entries, list)
> > +                     cycle = ktime_add_ns(cycle, entry->interval);
> > +             p->tcfg_cycletime = cycle;
> > +     }
> > +
> > +     if (tb[TCA_GATE_CYCLE_TIME_EXT])
> > +             p->tcfg_cycletime_ext =
> > +                     nla_get_u64(tb[TCA_GATE_CYCLE_TIME_EXT]);
> > +
> > +     p->tcfg_priority = prio;
> > +     p->tcfg_basetime = basetime;
> > +     p->tcfg_clockid = clockid;
> > +     p->tcfg_flags = gflags;
> > +
> > +     gact->tk_offset = tk_offset;
> > +     spin_lock_init(&gact->entry_lock);
> > +     hrtimer_init(&gact->hitimer, clockid, HRTIMER_MODE_ABS);
> > +     gact->hitimer.function = gate_timer_func;
> > +
> 
> One idea that just happened, if you find a way to enable RX timestamping
> and can rely that all packets have a timestamp, the code can simplified a
> lot. You wouldn't need any hrtimers, and deciding to drop or not a packet
> becomes a couple of mathematical operations. Seems worth a thought.

Thanks for the different ideas. The basic problem is we need to know now is a close time or open time in action. But I still don't know a better way than hrtimer to set the flag.

> 
> The real question is: if requiring for the driver to support at least software
> RX timestamping is excessive (doesn't seem so to me).

I understand.

> 
> 
> Cheers,
> --
> Vinicius

Thanks a lot!

Br,
Po Liu

Po Liu <po.liu@nxp.com> writes:

>> 
>> One idea that just happened, if you find a way to enable RX timestamping
>> and can rely that all packets have a timestamp, the code can simplified a
>> lot. You wouldn't need any hrtimers, and deciding to drop or not a packet
>> becomes a couple of mathematical operations. Seems worth a thought.
>
> Thanks for the different ideas. The basic problem is we need to know
> now is a close time or open time in action. But I still don't know a
> better way than hrtimer to set the flag.

That's the point, if you have the timestamp of when the packet arrived,
you can calculate if the gate is open and closed at that point. You
don't need to know "now", you work only in terms of "skb->tstamp"
(supposing that's where the timestamp is stored). In other words, it
doesn't matter when the packet arrives at the qdisc action, but when it
arrived at the controller, and the actions should be taken based on that
time.

>
>> 
>> The real question is: if requiring for the driver to support at least software
>> RX timestamping is excessive (doesn't seem so to me).
>
> I understand.
>
>> 
>> 
>> Cheers,
>> --
>> Vinicius
>
> Thanks a lot!
>
> Br,
> Po Liu

Br,
Po Liu

> -----Original Message-----
> From: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Sent: 2020年4月25日 1:41
> To: Po Liu <po.liu@nxp.com>; davem@davemloft.net; linux-
> kernel@vger.kernel.org; netdev@vger.kernel.org
> Cc: Claudiu Manoil <claudiu.manoil@nxp.com>; Vladimir Oltean
> <vladimir.oltean@nxp.com>; Alexandru Marginean
> <alexandru.marginean@nxp.com>; michael.chan@broadcom.com;
> vishal@chelsio.com; saeedm@mellanox.com; leon@kernel.org;
> jiri@mellanox.com; idosch@mellanox.com;
> alexandre.belloni@bootlin.com; UNGLinuxDriver@microchip.com;
> kuba@kernel.org; jhs@mojatatu.com; xiyou.wangcong@gmail.com;
> simon.horman@netronome.com; pablo@netfilter.org;
> moshe@mellanox.com; m-karicheri2@ti.com;
> andre.guedes@linux.intel.com; stephen@networkplumber.org
> Subject: RE: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control
> flow action
> 
> Caution: EXT Email
> 
> Po Liu <po.liu@nxp.com> writes:
> 
> >>
> >> One idea that just happened, if you find a way to enable RX
> >> timestamping and can rely that all packets have a timestamp, the code
> >> can simplified a lot. You wouldn't need any hrtimers, and deciding to
> >> drop or not a packet becomes a couple of mathematical operations.
> Seems worth a thought.
> >
> > Thanks for the different ideas. The basic problem is we need to know
> > now is a close time or open time in action. But I still don't know a
> > better way than hrtimer to set the flag.
> 
> That's the point, if you have the timestamp of when the packet arrived,
> you can calculate if the gate is open and closed at that point. You don't
> need to know "now", you work only in terms of "skb->tstamp"
> (supposing that's where the timestamp is stored). In other words, it
> doesn't matter when the packet arrives at the qdisc action, but when it
> arrived at the controller, and the actions should be taken based on that
> time.

I get your idea. But that would rely on the software timestamping on driver to be set.  By set all streams or by filtered stream each time set with tc flower filter. Also how the virtue net fix it is unknow.

> 
> >
> >>
> >> The real question is: if requiring for the driver to support at least
> >> software RX timestamping is excessive (doesn't seem so to me).
> >
> > I understand.
> >
> >>
> >>
> >> Cheers,
> >> --
> >> Vinicius
> >
> > Thanks a lot!
> >
> > Br,
> > Po Liu
> 
> --
> Vinicius