@@ -3,6 +3,7 @@
#define _GNU_SOURCE
#include <errno.h>
+#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
@@ -12,6 +13,8 @@
#include <linux/rtnetlink.h>
#include <linux/tc_act/tc_bpf.h>
#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
#include <bpf.h>
#include <nlattr.h>
@@ -48,6 +51,10 @@ struct bpf_filter_t {
int ifindex;
};
+struct bpf_attach_info {
+ __u32 flow_dissector_id;
+};
+
static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
{
struct bpf_netdev_t *netinfo = cookie;
@@ -180,8 +187,45 @@ static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
return 0;
}
+static int query_flow_dissector(struct bpf_attach_info *attach_info)
+{
+ __u32 attach_flags;
+ __u32 prog_ids[1];
+ __u32 prog_cnt;
+ int err;
+ int fd;
+
+ fd = open("/proc/self/ns/net", O_RDONLY);
+ if (fd < 0) {
+ p_err("can't open /proc/self/ns/net: %d",
+ strerror(errno));
+ return -1;
+ }
+ prog_cnt = ARRAY_SIZE(prog_ids);
+ err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0,
+ &attach_flags, prog_ids, &prog_cnt);
+ close(fd);
+ if (err) {
+ if (errno == EINVAL) {
+ /* Older kernel's don't support querying
+ * flow dissector programs.
+ */
+ errno = 0;
+ return 0;
+ }
+ p_err("can't query prog: %s", strerror(errno));
+ return -1;
+ }
+
+ if (prog_cnt == 1)
+ attach_info->flow_dissector_id = prog_ids[0];
+
+ return 0;
+}
+
static int do_show(int argc, char **argv)
{
+ struct bpf_attach_info attach_info = {};
int i, sock, ret, filter_idx = -1;
struct bpf_netdev_t dev_array;
unsigned int nl_pid;
@@ -199,6 +243,10 @@ static int do_show(int argc, char **argv)
usage();
}
+ ret = query_flow_dissector(&attach_info);
+ if (ret)
+ return -1;
+
sock = libbpf_netlink_open(&nl_pid);
if (sock < 0) {
fprintf(stderr, "failed to open netlink sock\n");
@@ -227,6 +275,12 @@ static int do_show(int argc, char **argv)
}
NET_END_ARRAY("\n");
}
+
+ NET_START_ARRAY("flow_dissector", "%s:\n");
+ if (attach_info.flow_dissector_id > 0)
+ NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id);
+ NET_END_ARRAY("\n");
+
NET_END_OBJECT;
if (json_output)
jsonw_end_array(json_wtr);
Right now there is no way to query whether BPF flow_dissector program is attached to a network namespace or not. In previous commit, I added support for querying that info, show it when doing `bpftool net`: $ bpftool prog loadall ./bpf_flow.o \ /sys/fs/bpf/flow type flow_dissector \ pinmaps /sys/fs/bpf/flow $ bpftool prog 3: flow_dissector name _dissect tag 8c9e917b513dd5cc gpl loaded_at 2019-04-23T16:14:48-0700 uid 0 xlated 656B jited 461B memlock 4096B map_ids 1,2 btf_id 1 ... $ bpftool net -j [{"xdp":[],"tc":[],"flow_dissector":[]}] $ bpftool prog attach pinned \ /sys/fs/bpf/flow/flow_dissector flow_dissector $ bpftool net -j [{"xdp":[],"tc":[],"flow_dissector":["id":3]}] Doesn't show up in a different net namespace: $ ip netns add test $ ip netns exec test bpftool net -j [{"xdp":[],"tc":[],"flow_dissector":[]}] Non-json output: $ bpftool net xdp: tc: flow_dissector: id 3 v2: * initialization order (Jakub Kicinski) * clear errno for batch mode (Quentin Monnet) Signed-off-by: Stanislav Fomichev <sdf@google.com> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> --- tools/bpf/bpftool/net.c | 54 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+)