utilities/nlmon.c

   1 /*
   2  * Copyright (c) 2009, 2010, 2011 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include <errno.h>
  19 #include <inttypes.h>
  20 #include <net/if.h>
  21 #include <poll.h>
  22 #include <sys/socket.h>
  23 #include <sys/uio.h>
  24 #include <stddef.h>
  25 #include <linux/rtnetlink.h>
  26 #include "netlink.h"
  27 #include "netlink-socket.h"
  28 #include "ofpbuf.h"
  29 #include "poll-loop.h"
  30 #include "timeval.h"
  31 #include "util.h"
  32 #include "vlog.h"
  33
  34 static const struct nl_policy rtnlgrp_link_policy[] = {
  35     [IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
  36     [IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
  37 };
  38
  39 int
  40 main(int argc OVS_UNUSED, char *argv[])
  41 {
  42     struct nl_sock *sock;
  43     int error;
  44
  45     set_program_name(argv[0]);
  46     vlog_set_levels(NULL, VLF_ANY_FACILITY, VLL_DBG);
  47
  48     error = nl_sock_create(NETLINK_ROUTE, &sock);
  49     if (error) {
  50         ovs_fatal(error, "could not create rtnetlink socket");
  51     }
  52
  53     error = nl_sock_join_mcgroup(sock, RTNLGRP_LINK);
  54     if (error) {
  55         ovs_fatal(error, "could not join RTNLGRP_LINK multicast group");
  56     }
  57
  58     for (;;) {
  59         struct ofpbuf *buf;
  60
  61         error = nl_sock_recv(sock, &buf, false);
  62         if (error == EAGAIN) {
  63             /* Nothing to do. */
  64         } else if (error == ENOBUFS) {
  65             ovs_error(0, "network monitor socket overflowed");
  66         } else if (error) {
  67             ovs_fatal(error, "error on network monitor socket");
  68         } else {
  69             struct nlattr *attrs[ARRAY_SIZE(rtnlgrp_link_policy)];
  70             struct nlmsghdr *nlh;
  71             struct ifinfomsg *iim;
  72
  73             nlh = ofpbuf_at(buf, 0, NLMSG_HDRLEN);
  74             iim = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *iim);
  75             if (!iim) {
  76                 ovs_error(0, "received bad rtnl message (no ifinfomsg)");
  77                 ofpbuf_delete(buf);
  78                 continue;
  79             }
  80
  81             if (!nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
  82                                  rtnlgrp_link_policy,
  83                                  attrs, ARRAY_SIZE(rtnlgrp_link_policy))) {
  84                 ovs_error(0, "received bad rtnl message (policy)");
  85                 ofpbuf_delete(buf);
  86                 continue;
  87             }
  88             printf("netdev %s changed (%s):\n",
  89                    nl_attr_get_string(attrs[IFLA_IFNAME]),
  90                    (nlh->nlmsg_type == RTM_NEWLINK ? "RTM_NEWLINK"
  91                     : nlh->nlmsg_type == RTM_DELLINK ? "RTM_DELLINK"
  92                     : nlh->nlmsg_type == RTM_GETLINK ? "RTM_GETLINK"
  93                     : nlh->nlmsg_type == RTM_SETLINK ? "RTM_SETLINK"
  94                     : "other"));
  95             if (attrs[IFLA_MASTER]) {
  96                 uint32_t idx = nl_attr_get_u32(attrs[IFLA_MASTER]);
  97                 char ifname[IFNAMSIZ];
  98                 if (!if_indextoname(idx, ifname)) {
  99                     strcpy(ifname, "unknown");
 100                 }
 101                 printf("\tmaster=%"PRIu32" (%s)\n", idx, ifname);
 102             }
 103             ofpbuf_delete(buf);
 104         }
 105
 106         nl_sock_wait(sock, POLLIN);
 107         poll_block();
 108     }
 109 }
 110