tools/bpf/bpftool/net.c

   1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 // Copyright (C) 2018 Facebook
   3
   4 #define _GNU_SOURCE
   5 #include <errno.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9 #include <libbpf.h>
  10 #include <net/if.h>
  11 #include <linux/if.h>
  12 #include <linux/rtnetlink.h>
  13 #include <linux/tc_act/tc_bpf.h>
  14 #include <sys/socket.h>
  15
  16 #include <bpf.h>
  17 #include <nlattr.h>
  18 #include "main.h"
  19 #include "netlink_dumper.h"
  20
  21 struct ip_devname_ifindex {
  22         char    devname[64];
  23         int     ifindex;
  24 };
  25
  26 struct bpf_netdev_t {
  27         struct ip_devname_ifindex *devices;
  28         int     used_len;
  29         int     array_len;
  30         int     filter_idx;
  31 };
  32
  33 struct tc_kind_handle {
  34         char    kind[64];
  35         int     handle;
  36 };
  37
  38 struct bpf_tcinfo_t {
  39         struct tc_kind_handle   *handle_array;
  40         int                     used_len;
  41         int                     array_len;
  42         bool                    is_qdisc;
  43 };
  44
  45 struct bpf_filter_t {
  46         const char      *kind;
  47         const char      *devname;
  48         int             ifindex;
  49 };
  50
  51 static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
  52 {
  53         struct bpf_netdev_t *netinfo = cookie;
  54         struct ifinfomsg *ifinfo = msg;
  55
  56         if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index)
  57                 return 0;
  58
  59         if (netinfo->used_len == netinfo->array_len) {
  60                 netinfo->devices = realloc(netinfo->devices,
  61                         (netinfo->array_len + 16) *
  62                         sizeof(struct ip_devname_ifindex));
  63                 if (!netinfo->devices)
  64                         return -ENOMEM;
  65
  66                 netinfo->array_len += 16;
  67         }
  68         netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index;
  69         snprintf(netinfo->devices[netinfo->used_len].devname,
  70                  sizeof(netinfo->devices[netinfo->used_len].devname),
  71                  "%s",
  72                  tb[IFLA_IFNAME]
  73                          ? libbpf_nla_getattr_str(tb[IFLA_IFNAME])
  74                          : "");
  75         netinfo->used_len++;
  76
  77         return do_xdp_dump(ifinfo, tb);
  78 }
  79
  80 static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb)
  81 {
  82         struct bpf_tcinfo_t *tcinfo = cookie;
  83         struct tcmsg *info = msg;
  84
  85         if (tcinfo->is_qdisc) {
  86                 /* skip clsact qdisc */
  87                 if (tb[TCA_KIND] &&
  88                     strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0)
  89                         return 0;
  90                 if (info->tcm_handle == 0)
  91                         return 0;
  92         }
  93
  94         if (tcinfo->used_len == tcinfo->array_len) {
  95                 tcinfo->handle_array = realloc(tcinfo->handle_array,
  96                         (tcinfo->array_len + 16) * sizeof(struct tc_kind_handle));
  97                 if (!tcinfo->handle_array)
  98                         return -ENOMEM;
  99
 100                 tcinfo->array_len += 16;
 101         }
 102         tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;
 103         snprintf(tcinfo->handle_array[tcinfo->used_len].kind,
 104                  sizeof(tcinfo->handle_array[tcinfo->used_len].kind),
 105                  "%s",
 106                  tb[TCA_KIND]
 107                          ? libbpf_nla_getattr_str(tb[TCA_KIND])
 108                          : "unknown");
 109         tcinfo->used_len++;
 110
 111         return 0;
 112 }
 113
 114 static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
 115 {
 116         const struct bpf_filter_t *filter_info = cookie;
 117
 118         return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind,
 119                               filter_info->devname, filter_info->ifindex);
 120 }
 121
 122 static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 123                            struct ip_devname_ifindex *dev)
 124 {
 125         struct bpf_filter_t filter_info;
 126         struct bpf_tcinfo_t tcinfo;
 127         int i, handle, ret = 0;
 128
 129         tcinfo.handle_array = NULL;
 130         tcinfo.used_len = 0;
 131         tcinfo.array_len = 0;
 132
 133         tcinfo.is_qdisc = false;
 134         ret = libbpf_nl_get_class(sock, nl_pid, dev->ifindex,
 135                                   dump_class_qdisc_nlmsg, &tcinfo);
 136         if (ret)
 137                 goto out;
 138
 139         tcinfo.is_qdisc = true;
 140         ret = libbpf_nl_get_qdisc(sock, nl_pid, dev->ifindex,
 141                                   dump_class_qdisc_nlmsg, &tcinfo);
 142         if (ret)
 143                 goto out;
 144
 145         filter_info.devname = dev->devname;
 146         filter_info.ifindex = dev->ifindex;
 147         for (i = 0; i < tcinfo.used_len; i++) {
 148                 filter_info.kind = tcinfo.handle_array[i].kind;
 149                 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex,
 150                                            tcinfo.handle_array[i].handle,
 151                                            dump_filter_nlmsg, &filter_info);
 152                 if (ret)
 153                         goto out;
 154         }
 155
 156         /* root, ingress and egress handle */
 157         handle = TC_H_ROOT;
 158         filter_info.kind = "root";
 159         ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
 160                                    dump_filter_nlmsg, &filter_info);
 161         if (ret)
 162                 goto out;
 163
 164         handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
 165         filter_info.kind = "clsact/ingress";
 166         ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
 167                                    dump_filter_nlmsg, &filter_info);
 168         if (ret)
 169                 goto out;
 170
 171         handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
 172         filter_info.kind = "clsact/egress";
 173         ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
 174                                    dump_filter_nlmsg, &filter_info);
 175         if (ret)
 176                 goto out;
 177
 178 out:
 179         free(tcinfo.handle_array);
 180         return 0;
 181 }
 182
 183 static int do_show(int argc, char **argv)
 184 {
 185         int i, sock, ret, filter_idx = -1;
 186         struct bpf_netdev_t dev_array;
 187         unsigned int nl_pid;
 188         char err_buf[256];
 189
 190         if (argc == 2) {
 191                 if (strcmp(argv[0], "dev") != 0)
 192                         usage();
 193                 filter_idx = if_nametoindex(argv[1]);
 194                 if (filter_idx == 0) {
 195                         fprintf(stderr, "invalid dev name %s\n", argv[1]);
 196                         return -1;
 197                 }
 198         } else if (argc != 0) {
 199                 usage();
 200         }
 201
 202         sock = libbpf_netlink_open(&nl_pid);
 203         if (sock < 0) {
 204                 fprintf(stderr, "failed to open netlink sock\n");
 205                 return -1;
 206         }
 207
 208         dev_array.devices = NULL;
 209         dev_array.used_len = 0;
 210         dev_array.array_len = 0;
 211         dev_array.filter_idx = filter_idx;
 212
 213         if (json_output)
 214                 jsonw_start_array(json_wtr);
 215         NET_START_OBJECT;
 216         NET_START_ARRAY("xdp", "%s:\n");
 217         ret = libbpf_nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
 218         NET_END_ARRAY("\n");
 219
 220         if (!ret) {
 221                 NET_START_ARRAY("tc", "%s:\n");
 222                 for (i = 0; i < dev_array.used_len; i++) {
 223                         ret = show_dev_tc_bpf(sock, nl_pid,
 224                                               &dev_array.devices[i]);
 225                         if (ret)
 226                                 break;
 227                 }
 228                 NET_END_ARRAY("\n");
 229         }
 230         NET_END_OBJECT;
 231         if (json_output)
 232                 jsonw_end_array(json_wtr);
 233
 234         if (ret) {
 235                 if (json_output)
 236                         jsonw_null(json_wtr);
 237                 libbpf_strerror(ret, err_buf, sizeof(err_buf));
 238                 fprintf(stderr, "Error: %s\n", err_buf);
 239         }
 240         free(dev_array.devices);
 241         close(sock);
 242         return ret;
 243 }
 244
 245 static int do_help(int argc, char **argv)
 246 {
 247         if (json_output) {
 248                 jsonw_null(json_wtr);
 249                 return 0;
 250         }
 251
 252         fprintf(stderr,
 253                 "Usage: %s %s { show | list } [dev <devname>]\n"
 254                 "       %s %s help\n"
 255                 "Note: Only xdp and tc attachments are supported now.\n"
 256                 "      For progs attached to cgroups, use \"bpftool cgroup\"\n"
 257                 "      to dump program attachments. For program types\n"
 258                 "      sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
 259                 "      consult iproute2.\n",
 260                 bin_name, argv[-2], bin_name, argv[-2]);
 261
 262         return 0;
 263 }
 264
 265 static const struct cmd cmds[] = {
 266         { "show",       do_show },
 267         { "list",       do_show },
 268         { "help",       do_help },
 269         { 0 }
 270 };
 271
 272 int do_net(int argc, char **argv)
 273 {
 274         return cmd_select(cmds, argc, argv, do_help);
 275 }