samples/bpf/xdp1_user.c

   1 /* Copyright (c) 2016 PLUMgrid
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  */
   7 #include <linux/bpf.h>
   8 #include <linux/if_link.h>
   9 #include <assert.h>
  10 #include <errno.h>
  11 #include <signal.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16 #include <libgen.h>
  17 #include <sys/resource.h>
  18 #include <net/if.h>
  19
  20 #include "bpf_util.h"
  21 #include "bpf/bpf.h"
  22 #include "bpf/libbpf.h"
  23
  24 static int ifindex;
  25 static __u32 xdp_flags;
  26
  27 static void int_exit(int sig)
  28 {
  29         bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
  30         exit(0);
  31 }
  32
  33 /* simple per-protocol drop counter
  34  */
  35 static void poll_stats(int map_fd, int interval)
  36 {
  37         unsigned int nr_cpus = bpf_num_possible_cpus();
  38         __u64 values[nr_cpus], prev[UINT8_MAX] = { 0 };
  39         int i;
  40
  41         while (1) {
  42                 __u32 key = UINT32_MAX;
  43
  44                 sleep(interval);
  45
  46                 while (bpf_map_get_next_key(map_fd, &key, &key) != -1) {
  47                         __u64 sum = 0;
  48
  49                         assert(bpf_map_lookup_elem(map_fd, &key, values) == 0);
  50                         for (i = 0; i < nr_cpus; i++)
  51                                 sum += values[i];
  52                         if (sum > prev[key])
  53                                 printf("proto %u: %10llu pkt/s\n",
  54                                        key, (sum - prev[key]) / interval);
  55                         prev[key] = sum;
  56                 }
  57         }
  58 }
  59
  60 static void usage(const char *prog)
  61 {
  62         fprintf(stderr,
  63                 "usage: %s [OPTS] IFACE\n\n"
  64                 "OPTS:\n"
  65                 "    -S    use skb-mode\n"
  66                 "    -N    enforce native mode\n",
  67                 prog);
  68 }
  69
  70 int main(int argc, char **argv)
  71 {
  72         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
  73         struct bpf_prog_load_attr prog_load_attr = {
  74                 .prog_type      = BPF_PROG_TYPE_XDP,
  75         };
  76         const char *optstr = "SN";
  77         int prog_fd, map_fd, opt;
  78         struct bpf_object *obj;
  79         struct bpf_map *map;
  80         char filename[256];
  81
  82         while ((opt = getopt(argc, argv, optstr)) != -1) {
  83                 switch (opt) {
  84                 case 'S':
  85                         xdp_flags |= XDP_FLAGS_SKB_MODE;
  86                         break;
  87                 case 'N':
  88                         xdp_flags |= XDP_FLAGS_DRV_MODE;
  89                         break;
  90                 default:
  91                         usage(basename(argv[0]));
  92                         return 1;
  93                 }
  94         }
  95
  96         if (optind == argc) {
  97                 usage(basename(argv[0]));
  98                 return 1;
  99         }
 100
 101         if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 102                 perror("setrlimit(RLIMIT_MEMLOCK)");
 103                 return 1;
 104         }
 105
 106         ifindex = if_nametoindex(argv[1]);
 107         if (!ifindex) {
 108                 perror("if_nametoindex");
 109                 return 1;
 110         }
 111
 112         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 113         prog_load_attr.file = filename;
 114
 115         if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 116                 return 1;
 117
 118         map = bpf_map__next(NULL, obj);
 119         if (!map) {
 120                 printf("finding a map in obj file failed\n");
 121                 return 1;
 122         }
 123         map_fd = bpf_map__fd(map);
 124
 125         if (!prog_fd) {
 126                 printf("load_bpf_file: %s\n", strerror(errno));
 127                 return 1;
 128         }
 129
 130         signal(SIGINT, int_exit);
 131         signal(SIGTERM, int_exit);
 132
 133         if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
 134                 printf("link set xdp fd failed\n");
 135                 return 1;
 136         }
 137
 138         poll_stats(map_fd, 2);
 139
 140         return 0;
 141 }