bpftool: show flow_dissector attachment status
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> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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parent
118c8e9ae6
commit
7f0c57fec8
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@ -3,6 +3,7 @@
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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@ -12,6 +13,8 @@
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#include <linux/rtnetlink.h>
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#include <linux/tc_act/tc_bpf.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <bpf.h>
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#include <nlattr.h>
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@ -48,6 +51,10 @@ struct bpf_filter_t {
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int ifindex;
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};
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struct bpf_attach_info {
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__u32 flow_dissector_id;
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};
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static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
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{
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struct bpf_netdev_t *netinfo = cookie;
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@ -180,8 +187,45 @@ out:
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return 0;
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}
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static int query_flow_dissector(struct bpf_attach_info *attach_info)
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{
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__u32 attach_flags;
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__u32 prog_ids[1];
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__u32 prog_cnt;
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int err;
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int fd;
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fd = open("/proc/self/ns/net", O_RDONLY);
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if (fd < 0) {
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p_err("can't open /proc/self/ns/net: %d",
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strerror(errno));
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return -1;
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}
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prog_cnt = ARRAY_SIZE(prog_ids);
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err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0,
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&attach_flags, prog_ids, &prog_cnt);
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close(fd);
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if (err) {
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if (errno == EINVAL) {
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/* Older kernel's don't support querying
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* flow dissector programs.
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*/
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errno = 0;
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return 0;
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}
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p_err("can't query prog: %s", strerror(errno));
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return -1;
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}
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if (prog_cnt == 1)
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attach_info->flow_dissector_id = prog_ids[0];
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return 0;
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}
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static int do_show(int argc, char **argv)
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{
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struct bpf_attach_info attach_info = {};
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int i, sock, ret, filter_idx = -1;
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struct bpf_netdev_t dev_array;
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unsigned int nl_pid;
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@ -199,6 +243,10 @@ static int do_show(int argc, char **argv)
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usage();
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}
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ret = query_flow_dissector(&attach_info);
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if (ret)
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return -1;
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sock = libbpf_netlink_open(&nl_pid);
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if (sock < 0) {
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fprintf(stderr, "failed to open netlink sock\n");
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@ -227,6 +275,12 @@ static int do_show(int argc, char **argv)
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}
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NET_END_ARRAY("\n");
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}
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NET_START_ARRAY("flow_dissector", "%s:\n");
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if (attach_info.flow_dissector_id > 0)
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NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id);
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NET_END_ARRAY("\n");
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NET_END_OBJECT;
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if (json_output)
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jsonw_end_array(json_wtr);
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