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_util.h"
  26 #include <bpf/bpf.h>
  27 #include "bpf/libbpf.h"
  28
  29 static int ifindex_in;
  30 static int ifindex_out;
  31 static bool ifindex_out_xdp_dummy_attached = true;
  32 static __u32 prog_id;
  33 static __u32 dummy_prog_id;
  34
  35 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
  36 static int rxcnt_map_fd;
  37
  38 static void int_exit(int sig)
  39 {
  40         __u32 curr_prog_id = 0;
  41
  42         if (bpf_get_link_xdp_id(ifindex_in, &curr_prog_id, xdp_flags)) {
  43                 printf("bpf_get_link_xdp_id failed\n");
  44                 exit(1);
  45         }
  46         if (prog_id == curr_prog_id)
  47                 bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
  48         else if (!curr_prog_id)
  49                 printf("couldn't find a prog id on iface IN\n");
  50         else
  51                 printf("program on iface IN changed, not removing\n");
  52
  53         if (ifindex_out_xdp_dummy_attached) {
  54                 curr_prog_id = 0;
  55                 if (bpf_get_link_xdp_id(ifindex_out, &curr_prog_id,
  56                                         xdp_flags)) {
  57                         printf("bpf_get_link_xdp_id failed\n");
  58                         exit(1);
  59                 }
  60                 if (dummy_prog_id == curr_prog_id)
  61                         bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
  62                 else if (!curr_prog_id)
  63                         printf("couldn't find a prog id on iface OUT\n");
  64                 else
  65                         printf("program on iface OUT changed, not removing\n");
  66         }
  67         exit(0);
  68 }
  69
  70 static void poll_stats(int interval, int ifindex)
  71 {
  72         unsigned int nr_cpus = bpf_num_possible_cpus();
  73         __u64 values[nr_cpus], prev[nr_cpus];
  74
  75         memset(prev, 0, sizeof(prev));
  76
  77         while (1) {
  78                 __u64 sum = 0;
  79                 __u32 key = 0;
  80                 int i;
  81
  82                 sleep(interval);
  83                 assert(bpf_map_lookup_elem(rxcnt_map_fd, &key, values) == 0);
  84                 for (i = 0; i < nr_cpus; i++)
  85                         sum += (values[i] - prev[i]);
  86                 if (sum)
  87                         printf("ifindex %i: %10llu pkt/s\n",
  88                                ifindex, sum / interval);
  89                 memcpy(prev, values, sizeof(values));
  90         }
  91 }
  92
  93 static void usage(const char *prog)
  94 {
  95         fprintf(stderr,
  96                 "usage: %s [OPTS] IFINDEX_IN IFINDEX_OUT\n\n"
  97                 "OPTS:\n"
  98                 "    -S    use skb-mode\n"
  99                 "    -N    enforce native mode\n"
 100                 "    -F    force loading prog\n",
 101                 prog);
 102 }
 103
 104
 105 int main(int argc, char **argv)
 106 {
 107         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 108         struct bpf_prog_load_attr prog_load_attr = {
 109                 .prog_type      = BPF_PROG_TYPE_XDP,
 110         };
 111         struct bpf_program *prog, *dummy_prog;
 112         int prog_fd, tx_port_map_fd, opt;
 113         struct bpf_prog_info info = {};
 114         __u32 info_len = sizeof(info);
 115         const char *optstr = "FSN";
 116         struct bpf_object *obj;
 117         char filename[256];
 118         int dummy_prog_fd;
 119         int ret, key = 0;
 120
 121         while ((opt = getopt(argc, argv, optstr)) != -1) {
 122                 switch (opt) {
 123                 case 'S':
 124                         xdp_flags |= XDP_FLAGS_SKB_MODE;
 125                         break;
 126                 case 'N':
 127                         xdp_flags |= XDP_FLAGS_DRV_MODE;
 128                         break;
 129                 case 'F':
 130                         xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
 131                         break;
 132                 default:
 133                         usage(basename(argv[0]));
 134                         return 1;
 135                 }
 136         }
 137
 138         if (optind == argc) {
 139                 printf("usage: %s IFINDEX_IN IFINDEX_OUT\n", argv[0]);
 140                 return 1;
 141         }
 142
 143         if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 144                 perror("setrlimit(RLIMIT_MEMLOCK)");
 145                 return 1;
 146         }
 147
 148         ifindex_in = strtoul(argv[optind], NULL, 0);
 149         ifindex_out = strtoul(argv[optind + 1], NULL, 0);
 150         printf("input: %d output: %d\n", ifindex_in, ifindex_out);
 151
 152         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 153         prog_load_attr.file = filename;
 154
 155         if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 156                 return 1;
 157
 158         prog = bpf_program__next(NULL, obj);
 159         dummy_prog = bpf_program__next(prog, obj);
 160         if (!prog || !dummy_prog) {
 161                 printf("finding a prog in obj file failed\n");
 162                 return 1;
 163         }
 164         /* bpf_prog_load_xattr gives us the pointer to first prog's fd,
 165          * so we're missing only the fd for dummy prog
 166          */
 167         dummy_prog_fd = bpf_program__fd(dummy_prog);
 168         if (prog_fd < 0 || dummy_prog_fd < 0) {
 169                 printf("bpf_prog_load_xattr: %s\n", strerror(errno));
 170                 return 1;
 171         }
 172
 173         tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port");
 174         rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
 175         if (tx_port_map_fd < 0 || rxcnt_map_fd < 0) {
 176                 printf("bpf_object__find_map_fd_by_name failed\n");
 177                 return 1;
 178         }
 179
 180         if (bpf_set_link_xdp_fd(ifindex_in, prog_fd, xdp_flags) < 0) {
 181                 printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
 182                 return 1;
 183         }
 184
 185         ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
 186         if (ret) {
 187                 printf("can't get prog info - %s\n", strerror(errno));
 188                 return ret;
 189         }
 190         prog_id = info.id;
 191
 192         /* Loading dummy XDP prog on out-device */
 193         if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
 194                             (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
 195                 printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
 196                 ifindex_out_xdp_dummy_attached = false;
 197         }
 198
 199         memset(&info, 0, sizeof(info));
 200         ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
 201         if (ret) {
 202                 printf("can't get prog info - %s\n", strerror(errno));
 203                 return ret;
 204         }
 205         dummy_prog_id = info.id;
 206
 207         signal(SIGINT, int_exit);
 208         signal(SIGTERM, int_exit);
 209
 210         /* bpf redirect port */
 211         ret = bpf_map_update_elem(tx_port_map_fd, &key, &ifindex_out, 0);
 212         if (ret) {
 213                 perror("bpf_update_elem");
 214                 goto out;
 215         }
 216
 217         poll_stats(2, ifindex_out);
 218
 219 out:
 220         return 0;
 221 }