samples/bpf/xdp1_user.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2016 PLUMgrid
   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 <string.h>
  12 #include <unistd.h>
  13 #include <libgen.h>
  14 #include <sys/resource.h>
  15 #include <net/if.h>
  16
  17 #include "bpf_util.h"
  18 #include <bpf/bpf.h>
  19 #include <bpf/libbpf.h>
  20
  21 static int ifindex;
  22 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
  23 static __u32 prog_id;
  24
  25 static void int_exit(int sig)
  26 {
  27         __u32 curr_prog_id = 0;
  28
  29         if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
  30                 printf("bpf_get_link_xdp_id failed\n");
  31                 exit(1);
  32         }
  33         if (prog_id == curr_prog_id)
  34                 bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
  35         else if (!curr_prog_id)
  36                 printf("couldn't find a prog id on a given interface\n");
  37         else
  38                 printf("program on interface changed, not removing\n");
  39         exit(0);
  40 }
  41
  42 /* simple per-protocol drop counter
  43  */
  44 static void poll_stats(int map_fd, int interval)
  45 {
  46         unsigned int nr_cpus = bpf_num_possible_cpus();
  47         __u64 values[nr_cpus], prev[UINT8_MAX] = { 0 };
  48         int i;
  49
  50         while (1) {
  51                 __u32 key = UINT32_MAX;
  52
  53                 sleep(interval);
  54
  55                 while (bpf_map_get_next_key(map_fd, &key, &key) != -1) {
  56                         __u64 sum = 0;
  57
  58                         assert(bpf_map_lookup_elem(map_fd, &key, values) == 0);
  59                         for (i = 0; i < nr_cpus; i++)
  60                                 sum += values[i];
  61                         if (sum > prev[key])
  62                                 printf("proto %u: %10llu pkt/s\n",
  63                                        key, (sum - prev[key]) / interval);
  64                         prev[key] = sum;
  65                 }
  66         }
  67 }
  68
  69 static void usage(const char *prog)
  70 {
  71         fprintf(stderr,
  72                 "usage: %s [OPTS] IFACE\n\n"
  73                 "OPTS:\n"
  74                 "    -S    use skb-mode\n"
  75                 "    -N    enforce native mode\n"
  76                 "    -F    force loading prog\n",
  77                 prog);
  78 }
  79
  80 int main(int argc, char **argv)
  81 {
  82         struct bpf_prog_load_attr prog_load_attr = {
  83                 .prog_type      = BPF_PROG_TYPE_XDP,
  84         };
  85         struct bpf_prog_info info = {};
  86         __u32 info_len = sizeof(info);
  87         const char *optstr = "FSN";
  88         int prog_fd, map_fd, opt;
  89         struct bpf_object *obj;
  90         struct bpf_map *map;
  91         char filename[256];
  92         int err;
  93
  94         while ((opt = getopt(argc, argv, optstr)) != -1) {
  95                 switch (opt) {
  96                 case 'S':
  97                         xdp_flags |= XDP_FLAGS_SKB_MODE;
  98                         break;
  99                 case 'N':
 100                         /* default, set below */
 101                         break;
 102                 case 'F':
 103                         xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
 104                         break;
 105                 default:
 106                         usage(basename(argv[0]));
 107                         return 1;
 108                 }
 109         }
 110
 111         if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
 112                 xdp_flags |= XDP_FLAGS_DRV_MODE;
 113
 114         if (optind == argc) {
 115                 usage(basename(argv[0]));
 116                 return 1;
 117         }
 118
 119         ifindex = if_nametoindex(argv[optind]);
 120         if (!ifindex) {
 121                 perror("if_nametoindex");
 122                 return 1;
 123         }
 124
 125         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 126         prog_load_attr.file = filename;
 127
 128         if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 129                 return 1;
 130
 131         map = bpf_map__next(NULL, obj);
 132         if (!map) {
 133                 printf("finding a map in obj file failed\n");
 134                 return 1;
 135         }
 136         map_fd = bpf_map__fd(map);
 137
 138         if (!prog_fd) {
 139                 printf("bpf_prog_load_xattr: %s\n", strerror(errno));
 140                 return 1;
 141         }
 142
 143         signal(SIGINT, int_exit);
 144         signal(SIGTERM, int_exit);
 145
 146         if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
 147                 printf("link set xdp fd failed\n");
 148                 return 1;
 149         }
 150
 151         err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
 152         if (err) {
 153                 printf("can't get prog info - %s\n", strerror(errno));
 154                 return err;
 155         }
 156         prog_id = info.id;
 157
 158         poll_stats(map_fd, 2);
 159
 160         return 0;
 161 }