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7f0c57fec8
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>
330 lines
7.4 KiB
C
330 lines
7.4 KiB
C
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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// Copyright (C) 2018 Facebook
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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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#include <libbpf.h>
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#include <net/if.h>
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#include <linux/if.h>
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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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#include "main.h"
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#include "netlink_dumper.h"
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struct ip_devname_ifindex {
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char devname[64];
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int ifindex;
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};
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struct bpf_netdev_t {
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struct ip_devname_ifindex *devices;
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int used_len;
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int array_len;
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int filter_idx;
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};
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struct tc_kind_handle {
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char kind[64];
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int handle;
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};
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struct bpf_tcinfo_t {
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struct tc_kind_handle *handle_array;
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int used_len;
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int array_len;
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bool is_qdisc;
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};
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struct bpf_filter_t {
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const char *kind;
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const char *devname;
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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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struct ifinfomsg *ifinfo = msg;
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if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index)
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return 0;
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if (netinfo->used_len == netinfo->array_len) {
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netinfo->devices = realloc(netinfo->devices,
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(netinfo->array_len + 16) *
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sizeof(struct ip_devname_ifindex));
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if (!netinfo->devices)
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return -ENOMEM;
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netinfo->array_len += 16;
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}
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netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index;
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snprintf(netinfo->devices[netinfo->used_len].devname,
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sizeof(netinfo->devices[netinfo->used_len].devname),
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"%s",
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tb[IFLA_IFNAME]
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? libbpf_nla_getattr_str(tb[IFLA_IFNAME])
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: "");
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netinfo->used_len++;
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return do_xdp_dump(ifinfo, tb);
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}
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static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb)
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{
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struct bpf_tcinfo_t *tcinfo = cookie;
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struct tcmsg *info = msg;
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if (tcinfo->is_qdisc) {
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/* skip clsact qdisc */
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if (tb[TCA_KIND] &&
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strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0)
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return 0;
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if (info->tcm_handle == 0)
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return 0;
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}
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if (tcinfo->used_len == tcinfo->array_len) {
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tcinfo->handle_array = realloc(tcinfo->handle_array,
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(tcinfo->array_len + 16) * sizeof(struct tc_kind_handle));
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if (!tcinfo->handle_array)
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return -ENOMEM;
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tcinfo->array_len += 16;
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}
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tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;
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snprintf(tcinfo->handle_array[tcinfo->used_len].kind,
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sizeof(tcinfo->handle_array[tcinfo->used_len].kind),
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"%s",
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tb[TCA_KIND]
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? libbpf_nla_getattr_str(tb[TCA_KIND])
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: "unknown");
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tcinfo->used_len++;
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return 0;
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}
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static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
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{
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const struct bpf_filter_t *filter_info = cookie;
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return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind,
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filter_info->devname, filter_info->ifindex);
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}
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static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
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struct ip_devname_ifindex *dev)
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{
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struct bpf_filter_t filter_info;
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struct bpf_tcinfo_t tcinfo;
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int i, handle, ret = 0;
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tcinfo.handle_array = NULL;
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tcinfo.used_len = 0;
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tcinfo.array_len = 0;
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tcinfo.is_qdisc = false;
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ret = libbpf_nl_get_class(sock, nl_pid, dev->ifindex,
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dump_class_qdisc_nlmsg, &tcinfo);
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if (ret)
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goto out;
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tcinfo.is_qdisc = true;
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ret = libbpf_nl_get_qdisc(sock, nl_pid, dev->ifindex,
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dump_class_qdisc_nlmsg, &tcinfo);
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if (ret)
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goto out;
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filter_info.devname = dev->devname;
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filter_info.ifindex = dev->ifindex;
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for (i = 0; i < tcinfo.used_len; i++) {
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filter_info.kind = tcinfo.handle_array[i].kind;
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ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex,
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tcinfo.handle_array[i].handle,
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dump_filter_nlmsg, &filter_info);
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if (ret)
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goto out;
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}
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/* root, ingress and egress handle */
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handle = TC_H_ROOT;
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filter_info.kind = "root";
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ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
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dump_filter_nlmsg, &filter_info);
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if (ret)
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goto out;
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handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
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filter_info.kind = "clsact/ingress";
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ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
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dump_filter_nlmsg, &filter_info);
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if (ret)
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goto out;
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handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
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filter_info.kind = "clsact/egress";
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ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
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dump_filter_nlmsg, &filter_info);
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if (ret)
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goto out;
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out:
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free(tcinfo.handle_array);
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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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char err_buf[256];
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if (argc == 2) {
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if (strcmp(argv[0], "dev") != 0)
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usage();
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filter_idx = if_nametoindex(argv[1]);
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if (filter_idx == 0) {
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fprintf(stderr, "invalid dev name %s\n", argv[1]);
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return -1;
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}
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} else if (argc != 0) {
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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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return -1;
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}
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dev_array.devices = NULL;
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dev_array.used_len = 0;
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dev_array.array_len = 0;
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dev_array.filter_idx = filter_idx;
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if (json_output)
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jsonw_start_array(json_wtr);
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NET_START_OBJECT;
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NET_START_ARRAY("xdp", "%s:\n");
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ret = libbpf_nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
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NET_END_ARRAY("\n");
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if (!ret) {
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NET_START_ARRAY("tc", "%s:\n");
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for (i = 0; i < dev_array.used_len; i++) {
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ret = show_dev_tc_bpf(sock, nl_pid,
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&dev_array.devices[i]);
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if (ret)
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break;
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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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if (ret) {
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if (json_output)
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jsonw_null(json_wtr);
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libbpf_strerror(ret, err_buf, sizeof(err_buf));
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fprintf(stderr, "Error: %s\n", err_buf);
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}
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free(dev_array.devices);
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close(sock);
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return ret;
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}
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static int do_help(int argc, char **argv)
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{
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if (json_output) {
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jsonw_null(json_wtr);
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return 0;
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}
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fprintf(stderr,
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"Usage: %s %s { show | list } [dev <devname>]\n"
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" %s %s help\n"
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"Note: Only xdp and tc attachments are supported now.\n"
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" For progs attached to cgroups, use \"bpftool cgroup\"\n"
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" to dump program attachments. For program types\n"
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" sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
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" consult iproute2.\n",
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bin_name, argv[-2], bin_name, argv[-2]);
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return 0;
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}
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static const struct cmd cmds[] = {
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{ "show", do_show },
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{ "list", do_show },
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{ "help", do_help },
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{ 0 }
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};
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int do_net(int argc, char **argv)
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{
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return cmd_select(cmds, argc, argv, do_help);
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}
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