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 rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 101         struct bpf_prog_load_attr prog_load_attr = {
 102                 .prog_type      = BPF_PROG_TYPE_XDP,
 103         };
 104         struct bpf_program *prog, *dummy_prog;
 105         int prog_fd, tx_port_map_fd, opt;
 106         struct bpf_prog_info info = {};
 107         __u32 info_len = sizeof(info);
 108         const char *optstr = "FSN";
 109         struct bpf_object *obj;
 110         char filename[256];
 111         int dummy_prog_fd;
 112         int ret, key = 0;
 113
 114         while ((opt = getopt(argc, argv, optstr)) != -1) {
 115                 switch (opt) {
 116                 case 'S':
 117                         xdp_flags |= XDP_FLAGS_SKB_MODE;
 118                         break;
 119                 case 'N':
 120                         /* default, set below */
 121                         break;
 122                 case 'F':
 123                         xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
 124                         break;
 125                 default:
 126                         usage(basename(argv[0]));
 127                         return 1;
 128                 }
 129         }
 130
 131         if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
 132                 xdp_flags |= XDP_FLAGS_DRV_MODE;
 133
 134         if (optind == argc) {
 135                 printf("usage: %s <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n", argv[0]);
 136                 return 1;
 137         }
 138
 139         if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 140                 perror("setrlimit(RLIMIT_MEMLOCK)");
 141                 return 1;
 142         }
 143
 144         ifindex_in = if_nametoindex(argv[optind]);
 145         if (!ifindex_in)
 146                 ifindex_in = strtoul(argv[optind], NULL, 0);
 147
 148         ifindex_out = if_nametoindex(argv[optind + 1]);
 149         if (!ifindex_out)
 150                 ifindex_out = strtoul(argv[optind + 1], NULL, 0);
 151
 152         printf("input: %d output: %d\n", ifindex_in, ifindex_out);
 153
 154         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 155         prog_load_attr.file = filename;
 156
 157         if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 158                 return 1;
 159
 160         prog = bpf_program__next(NULL, obj);
 161         dummy_prog = bpf_program__next(prog, obj);
 162         if (!prog || !dummy_prog) {
 163                 printf("finding a prog in obj file failed\n");
 164                 return 1;
 165         }
 166         /* bpf_prog_load_xattr gives us the pointer to first prog's fd,
 167          * so we're missing only the fd for dummy prog
 168          */
 169         dummy_prog_fd = bpf_program__fd(dummy_prog);
 170         if (prog_fd < 0 || dummy_prog_fd < 0) {
 171                 printf("bpf_prog_load_xattr: %s\n", strerror(errno));
 172                 return 1;
 173         }
 174
 175         tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port");
 176         rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
 177         if (tx_port_map_fd < 0 || rxcnt_map_fd < 0) {
 178                 printf("bpf_object__find_map_fd_by_name failed\n");
 179                 return 1;
 180         }
 181
 182         if (bpf_set_link_xdp_fd(ifindex_in, prog_fd, xdp_flags) < 0) {
 183                 printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
 184                 return 1;
 185         }
 186
 187         ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
 188         if (ret) {
 189                 printf("can't get prog info - %s\n", strerror(errno));
 190                 return ret;
 191         }
 192         prog_id = info.id;
 193
 194         /* Loading dummy XDP prog on out-device */
 195         if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
 196                             (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
 197                 printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
 198                 ifindex_out_xdp_dummy_attached = false;
 199         }
 200
 201         memset(&info, 0, sizeof(info));
 202         ret = bpf_obj_get_info_by_fd(dummy_prog_fd, &info, &info_len);
 203         if (ret) {
 204                 printf("can't get prog info - %s\n", strerror(errno));
 205                 return ret;
 206         }
 207         dummy_prog_id = info.id;
 208
 209         signal(SIGINT, int_exit);
 210         signal(SIGTERM, int_exit);
 211
 212         /* bpf redirect port */
 213         ret = bpf_map_update_elem(tx_port_map_fd, &key, &ifindex_out, 0);
 214         if (ret) {
 215                 perror("bpf_update_elem");
 216                 goto out;
 217         }
 218
 219         poll_stats(2, ifindex_out);
 220
 221 out:
 222         return 0;
 223 }