samples/bpf/xdp_redirect_user.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
   3  */
   4 #include <linux/bpf.h>
   5 #include <linux/if_link.h>
   6 #include <assert.h>
   7 #include <errno.h>
   8 #include <signal.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <stdbool.h>
  12 #include <string.h>
  13 #include <net/if.h>
  14 #include <unistd.h>
  15 #include <libgen.h>
  16 #include <sys/resource.h>
  17
  18 #include "bpf_util.h"
  19 #include <bpf/bpf.h>
  20 #include <bpf/libbpf.h>
  21
  22 static int ifindex_in;
  23 static int ifindex_out;
  24 static bool ifindex_out_xdp_dummy_attached = true;
  25 static __u32 prog_id;
  26 static __u32 dummy_prog_id;
  27
  28 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
  29 static int rxcnt_map_fd;
  30
  31 static void int_exit(int sig)
  32 {
  33         __u32 curr_prog_id = 0;
  34
  35         if (bpf_get_link_xdp_id(ifindex_in, &curr_prog_id, xdp_flags)) {
  36                 printf("bpf_get_link_xdp_id failed\n");
  37                 exit(1);
  38         }
  39         if (prog_id == curr_prog_id)
  40                 bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
  41         else if (!curr_prog_id)
  42                 printf("couldn't find a prog id on iface IN\n");
  43         else
  44                 printf("program on iface IN changed, not removing\n");
  45
  46         if (ifindex_out_xdp_dummy_attached) {
  47                 curr_prog_id = 0;
  48                 if (bpf_get_link_xdp_id(ifindex_out, &curr_prog_id,
  49                                         xdp_flags)) {
  50                         printf("bpf_get_link_xdp_id failed\n");
  51                         exit(1);
  52                 }
  53                 if (dummy_prog_id == curr_prog_id)
  54                         bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
  55                 else if (!curr_prog_id)
  56                         printf("couldn't find a prog id on iface OUT\n");
  57                 else
  58                         printf("program on iface OUT changed, not removing\n");
  59         }
  60         exit(0);
  61 }
  62
  63 static void poll_stats(int interval, int ifindex)
  64 {
  65         unsigned int nr_cpus = bpf_num_possible_cpus();
  66         __u64 values[nr_cpus], prev[nr_cpus];
  67
  68         memset(prev, 0, sizeof(prev));
  69
  70         while (1) {
  71                 __u64 sum = 0;
  72                 __u32 key = 0;
  73                 int i;
  74
  75                 sleep(interval);
  76                 assert(bpf_map_lookup_elem(rxcnt_map_fd, &key, values) == 0);
  77                 for (i = 0; i < nr_cpus; i++)
  78                         sum += (values[i] - prev[i]);
  79                 if (sum)
  80                         printf("ifindex %i: %10llu pkt/s\n",
  81                                ifindex, sum / interval);
  82                 memcpy(prev, values, sizeof(values));
  83         }
  84 }
  85
  86 static void usage(const char *prog)
  87 {
  88         fprintf(stderr,
  89                 "usage: %s [OPTS] <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n\n"
  90                 "OPTS:\n"
  91                 "    -S    use skb-mode\n"
  92                 "    -N    enforce native mode\n"
  93                 "    -F    force loading prog\n",
  94                 prog);
  95 }
  96
  97
  98 int main(int argc, char **argv)
  99 {
 100         struct bpf_prog_load_attr prog_load_attr = {
 101                 .prog_type      = BPF_PROG_TYPE_XDP,
 102         };
 103         struct bpf_program *prog, *dummy_prog;
 104         int prog_fd, tx_port_map_fd, opt;
 105         struct bpf_prog_info info = {};
 106         __u32 info_len = sizeof(info);
 107         const char *optstr = "FSN";
 108         struct bpf_object *obj;
 109         char filename[256];
 110         int dummy_prog_fd;
 111         int ret, key = 0;
 112
 113         while ((opt = getopt(argc, argv, optstr)) != -1) {
 114                 switch (opt) {
 115                 case 'S':
 116                         xdp_flags |= XDP_FLAGS_SKB_MODE;
 117                         break;
 118                 case 'N':
 119                         /* default, set below */
 120                         break;
 121                 case 'F':
 122                         xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
 123                         break;
 124                 default:
 125                         usage(basename(argv[0]));
 126                         return 1;
 127                 }
 128         }
 129
 130         if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
 131                 xdp_flags |= XDP_FLAGS_DRV_MODE;
 132
 133         if (optind == argc) {
 134                 printf("usage: %s <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n", argv[0]);
 135                 return 1;
 136         }
 137
 138         ifindex_in = if_nametoindex(argv[optind]);
 139         if (!ifindex_in)
 140                 ifindex_in = strtoul(argv[optind], NULL, 0);
 141
 142         ifindex_out = if_nametoindex(argv[optind + 1]);
 143         if (!ifindex_out)
 144                 ifindex_out = strtoul(argv[optind + 1], NULL, 0);
 145
 146         printf("input: %d output: %d\n", ifindex_in, ifindex_out);
 147
 148         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 149         prog_load_attr.file = filename;
 150
 151         if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 152                 return 1;
 153
 154         prog = bpf_program__next(NULL, obj);
 155         dummy_prog = bpf_program__next(prog, obj);
 156         if (!prog || !dummy_prog) {
 157                 printf("finding a prog in obj file failed\n");
 158                 return 1;
 159         }
 160         /* bpf_prog_load_xattr gives us the pointer to first prog's fd,
 161          * so we're missing only the fd for dummy prog
 162          */
 163         dummy_prog_fd = bpf_program__fd(dummy_prog);
 164         if (prog_fd < 0 || dummy_prog_fd < 0) {
 165                 printf("bpf_prog_load_xattr: %s\n", strerror(errno));
 166                 return 1;
 167         }
 168
 169         tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port");
 170         rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
 171         if (tx_port_map_fd < 0 || rxcnt_map_fd < 0) {
 172                 printf("bpf_object__find_map_fd_by_name failed\n");
 173                 return 1;
 174         }
 175
 176         if (bpf_set_link_xdp_fd(ifindex_in, prog_fd, xdp_flags) < 0) {
 177                 printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
 178                 return 1;
 179         }
 180
 181         ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
 182         if (ret) {
 183                 printf("can't get prog info - %s\n", strerror(errno));
 184                 return ret;
 185         }
 186         prog_id = info.id;
 187
 188         /* Loading dummy XDP prog on out-device */
 189         if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
 190                             (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
 191                 printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
 192                 ifindex_out_xdp_dummy_attached = false;
 193         }
 194
 195         memset(&info, 0, sizeof(info));
 196         ret = bpf_obj_get_info_by_fd(dummy_prog_fd, &info, &info_len);
 197         if (ret) {
 198                 printf("can't get prog info - %s\n", strerror(errno));
 199                 return ret;
 200         }
 201         dummy_prog_id = info.id;
 202
 203         signal(SIGINT, int_exit);
 204         signal(SIGTERM, int_exit);
 205
 206         /* bpf redirect port */
 207         ret = bpf_map_update_elem(tx_port_map_fd, &key, &ifindex_out, 0);
 208         if (ret) {
 209                 perror("bpf_update_elem");
 210                 goto out;
 211         }
 212
 213         poll_stats(2, ifindex_out);
 214
 215 out:
 216         return 0;
 217 }