usr.sbin/rtsold/probe.c

   1 /*      $KAME: probe.c,v 1.17 2003/10/05 00:09:36 itojun Exp $  */
   2
   3 /*
   4  * Copyright (C) 1998 WIDE Project.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the project nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  * $FreeBSD$
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/types.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/socket.h>
  38 #include <sys/uio.h>
  39 #include <sys/queue.h>
  40
  41 #include <net/if.h>
  42 #include <net/if_var.h>
  43 #include <net/if_dl.h>
  44
  45 #include <netinet/in.h>
  46 #include <netinet6/in6_var.h>
  47 #include <netinet/icmp6.h>
  48 #include <netinet6/nd6.h>
  49
  50 #include <arpa/inet.h>
  51
  52 #include <errno.h>
  53 #include <unistd.h>
  54 #include <string.h>
  55 #include <syslog.h>
  56 #include <stdlib.h>
  57
  58 #include "rtsold.h"
  59
  60 static struct msghdr sndmhdr;
  61 static struct iovec sndiov[2];
  62 static int probesock;
  63 static void sendprobe(struct in6_addr *, struct ifinfo *);
  64
  65 int
  66 probe_init(void)
  67 {
  68         int scmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
  69             CMSG_SPACE(sizeof(int));
  70         static u_char *sndcmsgbuf = NULL;
  71
  72         if (sndcmsgbuf == NULL &&
  73             (sndcmsgbuf = (u_char *)malloc(scmsglen)) == NULL) {
  74                 warnmsg(LOG_ERR, __func__, "malloc failed");
  75                 return(-1);
  76         }
  77
  78         if ((probesock = socket(AF_INET6, SOCK_RAW, IPPROTO_NONE)) < 0) {
  79                 warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
  80                 return(-1);
  81         }
  82
  83         /* make the socket send-only */
  84         if (shutdown(probesock, 0)) {
  85                 warnmsg(LOG_ERR, __func__, "shutdown: %s", strerror(errno));
  86                 return(-1);
  87         }
  88
  89         /* initialize msghdr for sending packets */
  90         sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
  91         sndmhdr.msg_iov = sndiov;
  92         sndmhdr.msg_iovlen = 1;
  93         sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
  94         sndmhdr.msg_controllen = scmsglen;
  95         return(0);
  96 }
  97
  98 /*
  99  * Probe if each router in the default router list is still alive.
 100  */
 101 void
 102 defrouter_probe(struct ifinfo *ifinfo)
 103 {
 104         u_char ntopbuf[INET6_ADDRSTRLEN];
 105         struct in6_drlist dr;
 106         int s, i;
 107         int ifindex = ifinfo->sdl->sdl_index;
 108
 109         if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
 110                 warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
 111                 return;
 112         }
 113         memset(&dr, 0, sizeof(dr));
 114         strlcpy(dr.ifname, "lo0", sizeof dr.ifname); /* dummy interface */
 115         if (ioctl(s, SIOCGDRLST_IN6, (caddr_t)&dr) < 0) {
 116                 warnmsg(LOG_ERR, __func__, "ioctl(SIOCGDRLST_IN6): %s",
 117                     strerror(errno));
 118                 goto closeandend;
 119         }
 120
 121         for (i = 0; dr.defrouter[i].if_index && i < PRLSTSIZ; i++) {
 122                 if (ifindex && dr.defrouter[i].if_index == ifindex) {
 123                         /* sanity check */
 124                         if (!IN6_IS_ADDR_LINKLOCAL(&dr.defrouter[i].rtaddr)) {
 125                                 warnmsg(LOG_ERR, __func__,
 126                                     "default router list contains a "
 127                                     "non-link-local address(%s)",
 128                                     inet_ntop(AF_INET6,
 129                                     &dr.defrouter[i].rtaddr,
 130                                     ntopbuf, INET6_ADDRSTRLEN));
 131                                 continue; /* ignore the address */
 132                         }
 133                         sendprobe(&dr.defrouter[i].rtaddr, ifinfo);
 134                 }
 135         }
 136
 137 closeandend:
 138         close(s);
 139 }
 140
 141 static void
 142 sendprobe(struct in6_addr *addr, struct ifinfo *ifinfo)
 143 {
 144         u_char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
 145         struct sockaddr_in6 sa6_probe;
 146         struct in6_pktinfo *pi;
 147         struct cmsghdr *cm;
 148         u_int32_t ifindex = ifinfo->sdl->sdl_index;
 149         int hoplimit = 1;
 150
 151         memset(&sa6_probe, 0, sizeof(sa6_probe));
 152         sa6_probe.sin6_family = AF_INET6;
 153         sa6_probe.sin6_len = sizeof(sa6_probe);
 154         sa6_probe.sin6_addr = *addr;
 155         sa6_probe.sin6_scope_id = ifinfo->linkid;
 156
 157         sndmhdr.msg_name = (caddr_t)&sa6_probe;
 158         sndmhdr.msg_iov[0].iov_base = NULL;
 159         sndmhdr.msg_iov[0].iov_len = 0;
 160
 161         cm = CMSG_FIRSTHDR(&sndmhdr);
 162         /* specify the outgoing interface */
 163         cm->cmsg_level = IPPROTO_IPV6;
 164         cm->cmsg_type = IPV6_PKTINFO;
 165         cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
 166         pi = (struct in6_pktinfo *)CMSG_DATA(cm);
 167         memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));       /*XXX*/
 168         pi->ipi6_ifindex = ifindex;
 169
 170         /* specify the hop limit of the packet for safety */
 171         cm = CMSG_NXTHDR(&sndmhdr, cm);
 172         cm->cmsg_level = IPPROTO_IPV6;
 173         cm->cmsg_type = IPV6_HOPLIMIT;
 174         cm->cmsg_len = CMSG_LEN(sizeof(int));
 175         memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
 176
 177         warnmsg(LOG_DEBUG, __func__, "probe a router %s on %s",
 178             inet_ntop(AF_INET6, addr, ntopbuf, INET6_ADDRSTRLEN),
 179             if_indextoname(ifindex, ifnamebuf));
 180
 181         if (sendmsg(probesock, &sndmhdr, 0))
 182                 warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s",
 183                     if_indextoname(ifindex, ifnamebuf), strerror(errno));
 184 }