| Message ID | 20170518140738.19617-5-mlichvar@redhat.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thu, May 18, 2017 at 10:07 AM, Miroslav Lichvar <mlichvar@redhat.com> wrote: > Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message > for incoming packets with hardware timestamps. It contains the index of > the real interface which received the packet and the length of the > packet at layer 2. > > The index is useful with bonding, bridges and other interfaces, where > IP_PKTINFO doesn't allow applications to determine which PHC made the > timestamp. With the L2 length (and link speed) it is possible to > transpose preamble timestamps to trailer timestamps, which are used in > the NTP protocol. > > While this information could be provided by two new socket options > independently from timestamping, it doesn't look like they would be very > useful. With this option any performance impact is limited to hardware > timestamping. > > Use dev_get_by_napi_id() to get the device and its index. On kernels > with disabled CONFIG_NET_RX_BUSY_POLL or drivers not using NAPI, a zero > index will be returned in the control message. > > CC: Richard Cochran <richardcochran@gmail.com> > CC: Willem de Bruijn <willemb@google.com> > Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> > +SOF_TIMESTAMPING_OPT_PKTINFO: > + > + Enable the SCM_TIMESTAMPING_PKTINFO control message for incoming > + packets with hardware timestamps. The message contains struct > + scm_ts_pktinfo, which supplies the index of the real interface which > + received the packet and its length at layer 2. A valid (non-zero) > + interface index will be returned only if CONFIG_NET_RX_BUSY_POLL is > + enabled and the driver is using NAPI. It is probably good to explicitly call out that the remaining two fields are reserved and undefined. To stress that applications cannot be overly pedantic and start failing if these become non-zero.
On Thu, May 18, 2017 at 04:20:53PM -0400, Willem de Bruijn wrote: > On Thu, May 18, 2017 at 10:07 AM, Miroslav Lichvar <mlichvar@redhat.com> wrote: > > +SOF_TIMESTAMPING_OPT_PKTINFO: > > + > > + Enable the SCM_TIMESTAMPING_PKTINFO control message for incoming > > + packets with hardware timestamps. The message contains struct > > + scm_ts_pktinfo, which supplies the index of the real interface which > > + received the packet and its length at layer 2. A valid (non-zero) > > + interface index will be returned only if CONFIG_NET_RX_BUSY_POLL is > > + enabled and the driver is using NAPI. > > It is probably good to explicitly call out that the remaining two fields > are reserved and undefined. To stress that applications cannot be > overly pedantic and start failing if these become non-zero. Ok. I'm adding "The struct contains also two other fields, but they are reserved and undefined".
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt index 96f5069..600c6bf 100644 --- a/Documentation/networking/timestamping.txt +++ b/Documentation/networking/timestamping.txt @@ -193,6 +193,15 @@ SOF_TIMESTAMPING_OPT_STATS: the transmit timestamps, such as how long a certain block of data was limited by peer's receiver window. +SOF_TIMESTAMPING_OPT_PKTINFO: + + Enable the SCM_TIMESTAMPING_PKTINFO control message for incoming + packets with hardware timestamps. The message contains struct + scm_ts_pktinfo, which supplies the index of the real interface which + received the packet and its length at layer 2. A valid (non-zero) + interface index will be returned only if CONFIG_NET_RX_BUSY_POLL is + enabled and the driver is using NAPI. + New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate regardless of the setting of sysctl net.core.tstamp_allow_data. diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h index 2b48856..a5f6e81 100644 --- a/include/uapi/asm-generic/socket.h +++ b/include/uapi/asm-generic/socket.h @@ -100,4 +100,6 @@ #define SO_COOKIE 57 +#define SCM_TIMESTAMPING_PKTINFO 58 + #endif /* __ASM_GENERIC_SOCKET_H */ diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h index 0749fb1..dee74d3 100644 --- a/include/uapi/linux/net_tstamp.h +++ b/include/uapi/linux/net_tstamp.h @@ -9,6 +9,7 @@ #ifndef _NET_TIMESTAMPING_H #define _NET_TIMESTAMPING_H +#include <linux/types.h> #include <linux/socket.h> /* for SO_TIMESTAMPING */ /* SO_TIMESTAMPING gets an integer bit field comprised of these values */ @@ -26,8 +27,9 @@ enum { SOF_TIMESTAMPING_OPT_CMSG = (1<<10), SOF_TIMESTAMPING_OPT_TSONLY = (1<<11), SOF_TIMESTAMPING_OPT_STATS = (1<<12), + SOF_TIMESTAMPING_OPT_PKTINFO = (1<<13), - SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_STATS, + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_PKTINFO, SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | SOF_TIMESTAMPING_LAST }; @@ -130,4 +132,11 @@ enum hwtstamp_rx_filters { HWTSTAMP_FILTER_NTP_ALL, }; +/* SCM_TIMESTAMPING_PKTINFO control message */ +struct scm_ts_pktinfo { + __u32 if_index; + __u32 pkt_length; + __u32 reserved[2]; +}; + #endif /* _NET_TIMESTAMPING_H */ diff --git a/net/socket.c b/net/socket.c index c2564eb..67db7d8 100644 --- a/net/socket.c +++ b/net/socket.c @@ -662,6 +662,27 @@ static bool skb_is_err_queue(const struct sk_buff *skb) return skb->pkt_type == PACKET_OUTGOING; } +static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb) +{ + struct scm_ts_pktinfo ts_pktinfo; + struct net_device *orig_dev; + + if (!skb_mac_header_was_set(skb)) + return; + + memset(&ts_pktinfo, 0, sizeof(ts_pktinfo)); + + rcu_read_lock(); + orig_dev = dev_get_by_napi_id(skb_napi_id(skb)); + if (orig_dev) + ts_pktinfo.if_index = orig_dev->ifindex; + rcu_read_unlock(); + + ts_pktinfo.pkt_length = skb->len - skb_mac_offset(skb); + put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_PKTINFO, + sizeof(ts_pktinfo), &ts_pktinfo); +} + /* * called from sock_recv_timestamp() if sock_flag(sk, SOCK_RCVTSTAMP) */ @@ -699,8 +720,12 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, empty = 0; if (shhwtstamps && (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) && - ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2)) + ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2)) { empty = 0; + if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_PKTINFO) && + !skb_is_err_queue(skb)) + put_ts_pktinfo(msg, skb); + } if (!empty) { put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING, sizeof(tss), &tss);
Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message for incoming packets with hardware timestamps. It contains the index of the real interface which received the packet and the length of the packet at layer 2. The index is useful with bonding, bridges and other interfaces, where IP_PKTINFO doesn't allow applications to determine which PHC made the timestamp. With the L2 length (and link speed) it is possible to transpose preamble timestamps to trailer timestamps, which are used in the NTP protocol. While this information could be provided by two new socket options independently from timestamping, it doesn't look like they would be very useful. With this option any performance impact is limited to hardware timestamping. Use dev_get_by_napi_id() to get the device and its index. On kernels with disabled CONFIG_NET_RX_BUSY_POLL or drivers not using NAPI, a zero index will be returned in the control message. CC: Richard Cochran <richardcochran@gmail.com> CC: Willem de Bruijn <willemb@google.com> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> --- Documentation/networking/timestamping.txt | 9 +++++++++ include/uapi/asm-generic/socket.h | 2 ++ include/uapi/linux/net_tstamp.h | 11 ++++++++++- net/socket.c | 27 ++++++++++++++++++++++++++- 4 files changed, 47 insertions(+), 2 deletions(-)