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/netlink.h>
   9 #include <linux/rtnetlink.h>
  10 #include <assert.h>
  11 #include <errno.h>
  12 #include <signal.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/socket.h>
  17 #include <unistd.h>
  18 #include "bpf_load.h"
  19 #include "libbpf.h"
  20
  21 static int set_link_xdp_fd(int ifindex, int fd)
  22 {
  23         struct sockaddr_nl sa;
  24         int sock, seq = 0, len, ret = -1;
  25         char buf[4096];
  26         struct nlattr *nla, *nla_xdp;
  27         struct {
  28                 struct nlmsghdr  nh;
  29                 struct ifinfomsg ifinfo;
  30                 char             attrbuf[64];
  31         } req;
  32         struct nlmsghdr *nh;
  33         struct nlmsgerr *err;
  34
  35         memset(&sa, 0, sizeof(sa));
  36         sa.nl_family = AF_NETLINK;
  37
  38         sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
  39         if (sock < 0) {
  40                 printf("open netlink socket: %s\n", strerror(errno));
  41                 return -1;
  42         }
  43
  44         if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
  45                 printf("bind to netlink: %s\n", strerror(errno));
  46                 goto cleanup;
  47         }
  48
  49         memset(&req, 0, sizeof(req));
  50         req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
  51         req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
  52         req.nh.nlmsg_type = RTM_SETLINK;
  53         req.nh.nlmsg_pid = 0;
  54         req.nh.nlmsg_seq = ++seq;
  55         req.ifinfo.ifi_family = AF_UNSPEC;
  56         req.ifinfo.ifi_index = ifindex;
  57         nla = (struct nlattr *)(((char *)&req)
  58                                 + NLMSG_ALIGN(req.nh.nlmsg_len));
  59         nla->nla_type = NLA_F_NESTED | 43/*IFLA_XDP*/;
  60
  61         nla_xdp = (struct nlattr *)((char *)nla + NLA_HDRLEN);
  62         nla_xdp->nla_type = 1/*IFLA_XDP_FD*/;
  63         nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
  64         memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
  65         nla->nla_len = NLA_HDRLEN + nla_xdp->nla_len;
  66
  67         req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
  68
  69         if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
  70                 printf("send to netlink: %s\n", strerror(errno));
  71                 goto cleanup;
  72         }
  73
  74         len = recv(sock, buf, sizeof(buf), 0);
  75         if (len < 0) {
  76                 printf("recv from netlink: %s\n", strerror(errno));
  77                 goto cleanup;
  78         }
  79
  80         for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
  81              nh = NLMSG_NEXT(nh, len)) {
  82                 if (nh->nlmsg_pid != getpid()) {
  83                         printf("Wrong pid %d, expected %d\n",
  84                                nh->nlmsg_pid, getpid());
  85                         goto cleanup;
  86                 }
  87                 if (nh->nlmsg_seq != seq) {
  88                         printf("Wrong seq %d, expected %d\n",
  89                                nh->nlmsg_seq, seq);
  90                         goto cleanup;
  91                 }
  92                 switch (nh->nlmsg_type) {
  93                 case NLMSG_ERROR:
  94                         err = (struct nlmsgerr *)NLMSG_DATA(nh);
  95                         if (!err->error)
  96                                 continue;
  97                         printf("nlmsg error %s\n", strerror(-err->error));
  98                         goto cleanup;
  99                 case NLMSG_DONE:
 100                         break;
 101                 }
 102         }
 103
 104         ret = 0;
 105
 106 cleanup:
 107         close(sock);
 108         return ret;
 109 }
 110
 111 static int ifindex;
 112
 113 static void int_exit(int sig)
 114 {
 115         set_link_xdp_fd(ifindex, -1);
 116         exit(0);
 117 }
 118
 119 /* simple per-protocol drop counter
 120  */
 121 static void poll_stats(int interval)
 122 {
 123         unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
 124         const unsigned int nr_keys = 256;
 125         __u64 values[nr_cpus], prev[nr_keys][nr_cpus];
 126         __u32 key;
 127         int i;
 128
 129         memset(prev, 0, sizeof(prev));
 130
 131         while (1) {
 132                 sleep(interval);
 133
 134                 for (key = 0; key < nr_keys; key++) {
 135                         __u64 sum = 0;
 136
 137                         assert(bpf_lookup_elem(map_fd[0], &key, values) == 0);
 138                         for (i = 0; i < nr_cpus; i++)
 139                                 sum += (values[i] - prev[key][i]);
 140                         if (sum)
 141                                 printf("proto %u: %10llu pkt/s\n",
 142                                        key, sum / interval);
 143                         memcpy(prev[key], values, sizeof(values));
 144                 }
 145         }
 146 }
 147
 148 int main(int ac, char **argv)
 149 {
 150         char filename[256];
 151
 152         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 153
 154         if (ac != 2) {
 155                 printf("usage: %s IFINDEX\n", argv[0]);
 156                 return 1;
 157         }
 158
 159         ifindex = strtoul(argv[1], NULL, 0);
 160
 161         if (load_bpf_file(filename)) {
 162                 printf("%s", bpf_log_buf);
 163                 return 1;
 164         }
 165
 166         if (!prog_fd[0]) {
 167                 printf("load_bpf_file: %s\n", strerror(errno));
 168                 return 1;
 169         }
 170
 171         signal(SIGINT, int_exit);
 172
 173         if (set_link_xdp_fd(ifindex, prog_fd[0]) < 0) {
 174                 printf("link set xdp fd failed\n");
 175                 return 1;
 176         }
 177
 178         poll_stats(2);
 179
 180         return 0;
 181 }