LXR linux/samples/bpf/xdp1

   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
  18#include "bpf_load.h"
  19#include "bpf_util.h"
  20#include "libbpf.h"
  21
  22static int ifindex;
  23static __u32 xdp_flags;
  24
  25static void int_exit(int sig)
  26{
  27        set_link_xdp_fd(ifindex, -1, xdp_flags);
  28        exit(0);
  29}
  30
  31/* simple per-protocol drop counter
  32 */
  33static void poll_stats(int interval)
  34{
  35        unsigned int nr_cpus = bpf_num_possible_cpus();
  36        const unsigned int nr_keys = 256;
  37        __u64 values[nr_cpus], prev[nr_keys][nr_cpus];
  38        __u32 key;
  39        int i;
  40
  41        memset(prev, 0, sizeof(prev));
  42
  43        while (1) {
  44                sleep(interval);
  45
  46                for (key = 0; key < nr_keys; key++) {
  47                        __u64 sum = 0;
  48
  49                        assert(bpf_map_lookup_elem(map_fd[0], &key, values) == 0);
  50                        for (i = 0; i < nr_cpus; i++)
  51                                sum += (values[i] - prev[key][i]);
  52                        if (sum)
  53                                printf("proto %u: %10llu pkt/s\n",
  54                                       key, sum / interval);
  55                        memcpy(prev[key], values, sizeof(values));
  56                }
  57        }
  58}
  59
  60static void usage(const char *prog)
  61{
  62        fprintf(stderr,
  63                "usage: %s [OPTS] IFINDEX\n\n"
  64                "OPTS:\n"
  65                "    -S    use skb-mode\n"
  66                "    -N    enforce native mode\n",
  67                prog);
  68}
  69
  70int main(int argc, char **argv)
  71{
  72        const char *optstr = "SN";
  73        char filename[256];
  74        int opt;
  75
  76        while ((opt = getopt(argc, argv, optstr)) != -1) {
  77                switch (opt) {
  78                case 'S':
  79                        xdp_flags |= XDP_FLAGS_SKB_MODE;
  80                        break;
  81                case 'N':
  82                        xdp_flags |= XDP_FLAGS_DRV_MODE;
  83                        break;
  84                default:
  85                        usage(basename(argv[0]));
  86                        return 1;
  87                }
  88        }
  89
  90        if (optind == argc) {
  91                usage(basename(argv[0]));
  92                return 1;
  93        }
  94        ifindex = strtoul(argv[optind], NULL, 0);
  95
  96        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
  97
  98        if (load_bpf_file(filename)) {
  99                printf("%s", bpf_log_buf);
 100                return 1;
 101        }
 102
 103        if (!prog_fd[0]) {
 104                printf("load_bpf_file: %s\n", strerror(errno));
 105                return 1;
 106        }
 107
 108        signal(SIGINT, int_exit);
 109        signal(SIGTERM, int_exit);
 110
 111        if (set_link_xdp_fd(ifindex, prog_fd[0], xdp_flags) < 0) {
 112                printf("link set xdp fd failed\n");
 113                return 1;
 114        }
 115
 116        poll_stats(2);
 117
 118        return 0;
 119}
 120