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
  24 #include "bpf_load.h"
  25 #include "bpf_util.h"
  26 #include "libbpf.h"
  27
  28 static int ifindex_in;
  29 static int ifindex_out;
  30 static bool ifindex_out_xdp_dummy_attached = true;
  31
  32 static __u32 xdp_flags;
  33
  34 static void int_exit(int sig)
  35 {
  36         bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
  37         if (ifindex_out_xdp_dummy_attached)
  38                 bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
  39         exit(0);
  40 }
  41
  42 static void poll_stats(int interval, int ifindex)
  43 {
  44         unsigned int nr_cpus = bpf_num_possible_cpus();
  45         __u64 values[nr_cpus], prev[nr_cpus];
  46
  47         memset(prev, 0, sizeof(prev));
  48
  49         while (1) {
  50                 __u64 sum = 0;
  51                 __u32 key = 0;
  52                 int i;
  53
  54                 sleep(interval);
  55                 assert(bpf_map_lookup_elem(map_fd[1], &key, values) == 0);
  56                 for (i = 0; i < nr_cpus; i++)
  57                         sum += (values[i] - prev[i]);
  58                 if (sum)
  59                         printf("ifindex %i: %10llu pkt/s\n",
  60                                ifindex, sum / interval);
  61                 memcpy(prev, values, sizeof(values));
  62         }
  63 }
  64
  65 static void usage(const char *prog)
  66 {
  67         fprintf(stderr,
  68                 "usage: %s [OPTS] IFINDEX_IN IFINDEX_OUT\n\n"
  69                 "OPTS:\n"
  70                 "    -S    use skb-mode\n"
  71                 "    -N    enforce native mode\n",
  72                 prog);
  73 }
  74
  75
  76 int main(int argc, char **argv)
  77 {
  78         const char *optstr = "SN";
  79         char filename[256];
  80         int ret, opt, key = 0;
  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                 printf("usage: %s IFINDEX_IN IFINDEX_OUT\n", argv[0]);
  98                 return 1;
  99         }
 100
 101         ifindex_in = strtoul(argv[optind], NULL, 0);
 102         ifindex_out = strtoul(argv[optind + 1], NULL, 0);
 103         printf("input: %d output: %d\n", ifindex_in, ifindex_out);
 104
 105         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 106
 107         if (load_bpf_file(filename)) {
 108                 printf("%s", bpf_log_buf);
 109                 return 1;
 110         }
 111
 112         if (!prog_fd[0]) {
 113                 printf("load_bpf_file: %s\n", strerror(errno));
 114                 return 1;
 115         }
 116
 117         if (bpf_set_link_xdp_fd(ifindex_in, prog_fd[0], xdp_flags) < 0) {
 118                 printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
 119                 return 1;
 120         }
 121
 122         /* Loading dummy XDP prog on out-device */
 123         if (bpf_set_link_xdp_fd(ifindex_out, prog_fd[1],
 124                             (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
 125                 printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
 126                 ifindex_out_xdp_dummy_attached = false;
 127         }
 128
 129         signal(SIGINT, int_exit);
 130         signal(SIGTERM, int_exit);
 131
 132         /* bpf redirect port */
 133         ret = bpf_map_update_elem(map_fd[0], &key, &ifindex_out, 0);
 134         if (ret) {
 135                 perror("bpf_update_elem");
 136                 goto out;
 137         }
 138
 139         poll_stats(2, ifindex_out);
 140
 141 out:
 142         return 0;
 143 }