samples/bpf/xdp_redirect_user.c

   1 /* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
   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  * This program is distributed in the hope that it will be useful, but
   8  * WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10  * General Public License for more details.
  11  */
  12 #include <linux/bpf.h>
  13 #include <linux/if_link.h>
  14 #include <assert.h>
  15 #include <errno.h>
  16 #include <signal.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <stdbool.h>
  20 #include <string.h>
  21 #include <unistd.h>
  22 #include <libgen.h>
  23 #include <sys/resource.h>
  24
  25 #include "bpf_load.h"
  26 #include "bpf_util.h"
  27 #include <bpf/bpf.h>
  28
  29 static int ifindex_in;
  30 static int ifindex_out;
  31 static bool ifindex_out_xdp_dummy_attached = true;
  32
  33 static __u32 xdp_flags;
  34
  35 static void int_exit(int sig)
  36 {
  37         bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
  38         if (ifindex_out_xdp_dummy_attached)
  39                 bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
  40         exit(0);
  41 }
  42
  43 static void poll_stats(int interval, int ifindex)
  44 {
  45         unsigned int nr_cpus = bpf_num_possible_cpus();
  46         __u64 values[nr_cpus], prev[nr_cpus];
  47
  48         memset(prev, 0, sizeof(prev));
  49
  50         while (1) {
  51                 __u64 sum = 0;
  52                 __u32 key = 0;
  53                 int i;
  54
  55                 sleep(interval);
  56                 assert(bpf_map_lookup_elem(map_fd[1], &key, values) == 0);
  57                 for (i = 0; i < nr_cpus; i++)
  58                         sum += (values[i] - prev[i]);
  59                 if (sum)
  60                         printf("ifindex %i: %10llu pkt/s\n",
  61                                ifindex, sum / interval);
  62                 memcpy(prev, values, sizeof(values));
  63         }
  64 }
  65
  66 static void usage(const char *prog)
  67 {
  68         fprintf(stderr,
  69                 "usage: %s [OPTS] IFINDEX_IN IFINDEX_OUT\n\n"
  70                 "OPTS:\n"
  71                 "    -S    use skb-mode\n"
  72                 "    -N    enforce native mode\n",
  73                 prog);
  74 }
  75
  76
  77 int main(int argc, char **argv)
  78 {
  79         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
  80         const char *optstr = "SN";
  81         char filename[256];
  82         int ret, opt, key = 0;
  83
  84         while ((opt = getopt(argc, argv, optstr)) != -1) {
  85                 switch (opt) {
  86                 case 'S':
  87                         xdp_flags |= XDP_FLAGS_SKB_MODE;
  88                         break;
  89                 case 'N':
  90                         xdp_flags |= XDP_FLAGS_DRV_MODE;
  91                         break;
  92                 default:
  93                         usage(basename(argv[0]));
  94                         return 1;
  95                 }
  96         }
  97
  98         if (optind == argc) {
  99                 printf("usage: %s IFINDEX_IN IFINDEX_OUT\n", argv[0]);
 100                 return 1;
 101         }
 102
 103         if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 104                 perror("setrlimit(RLIMIT_MEMLOCK)");
 105                 return 1;
 106         }
 107
 108         ifindex_in = strtoul(argv[optind], NULL, 0);
 109         ifindex_out = strtoul(argv[optind + 1], NULL, 0);
 110         printf("input: %d output: %d\n", ifindex_in, ifindex_out);
 111
 112         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 113
 114         if (load_bpf_file(filename)) {
 115                 printf("%s", bpf_log_buf);
 116                 return 1;
 117         }
 118
 119         if (!prog_fd[0]) {
 120                 printf("load_bpf_file: %s\n", strerror(errno));
 121                 return 1;
 122         }
 123
 124         if (bpf_set_link_xdp_fd(ifindex_in, prog_fd[0], xdp_flags) < 0) {
 125                 printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
 126                 return 1;
 127         }
 128
 129         /* Loading dummy XDP prog on out-device */
 130         if (bpf_set_link_xdp_fd(ifindex_out, prog_fd[1],
 131                             (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
 132                 printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
 133                 ifindex_out_xdp_dummy_attached = false;
 134         }
 135
 136         signal(SIGINT, int_exit);
 137         signal(SIGTERM, int_exit);
 138
 139         /* bpf redirect port */
 140         ret = bpf_map_update_elem(map_fd[0], &key, &ifindex_out, 0);
 141         if (ret) {
 142                 perror("bpf_update_elem");
 143                 goto out;
 144         }
 145
 146         poll_stats(2, ifindex_out);
 147
 148 out:
 149         return 0;
 150 }