usr.sbin/rtsold/probe.c

   1 /*      $NetBSD: probe.c,v 1.9 2004/01/03 01:40:32 itojun Exp $ */
   2 /*      $KAME: probe.c,v 1.15 2002/05/31 21:22:08 itojun Exp $  */
   3
   4 /*
   5  * Copyright (C) 1998 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/types.h>
  35 #include <sys/ioctl.h>
  36 #include <sys/socket.h>
  37 #include <sys/uio.h>
  38 #include <sys/queue.h>
  39
  40 #include <net/if.h>
  41 #include <net/if_dl.h>
  42
  43 #include <netinet/in.h>
  44 #include <netinet6/in6_var.h>
  45 #include <netinet/icmp6.h>
  46 #include <netinet6/nd6.h>
  47
  48 #include <arpa/inet.h>
  49
  50 #include <errno.h>
  51 #include <unistd.h>
  52 #include <string.h>
  53 #include <syslog.h>
  54 #include <stdlib.h>
  55
  56 #include "rtsold.h"
  57
  58 static struct msghdr sndmhdr;
  59 static struct iovec sndiov[2];
  60 static int probesock;
  61 static void sendprobe __P((struct in6_addr *, struct ifinfo *));
  62
  63 int
  64 probe_init(void)
  65 {
  66         int scmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
  67             CMSG_SPACE(sizeof(int));
  68         static u_char *sndcmsgbuf = NULL;
  69
  70         if (sndcmsgbuf == NULL &&
  71             (sndcmsgbuf = (u_char *)malloc(scmsglen)) == NULL) {
  72                 warnmsg(LOG_ERR, __func__, "malloc failed");
  73                 return(-1);
  74         }
  75
  76         if ((probesock = socket(AF_INET6, SOCK_RAW, IPPROTO_NONE)) < 0) {
  77                 warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
  78                 return(-1);
  79         }
  80
  81         /* make the socket send-only */
  82         if (shutdown(probesock, 0)) {
  83                 warnmsg(LOG_ERR, __func__, "shutdown: %s", strerror(errno));
  84                 return(-1);
  85         }
  86
  87         /* initialize msghdr for sending packets */
  88         sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
  89         sndmhdr.msg_iov = sndiov;
  90         sndmhdr.msg_iovlen = 1;
  91         sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
  92         sndmhdr.msg_controllen = scmsglen;
  93         return(0);
  94 }
  95
  96 /*
  97  * Probe if each router in the default router list is still alive.
  98  */
  99 void
 100 defrouter_probe(struct ifinfo *ifinfo)
 101 {
 102         char ntopbuf[INET6_ADDRSTRLEN];
 103         struct in6_drlist dr;
 104         int s, i;
 105         int ifindex = ifinfo->sdl->sdl_index;
 106
 107         if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
 108                 warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
 109                 return;
 110         }
 111         memset(&dr, 0, sizeof(dr));
 112         strlcpy(dr.ifname, "lo0", sizeof dr.ifname); /* dummy interface */
 113         if (ioctl(s, SIOCGDRLST_IN6, (caddr_t)&dr) < 0) {
 114                 warnmsg(LOG_ERR, __func__, "ioctl(SIOCGDRLST_IN6): %s",
 115                     strerror(errno));
 116                 goto closeandend;
 117         }
 118
 119         for (i = 0; dr.defrouter[i].if_index && i < PRLSTSIZ; i++) {
 120                 if (ifindex && dr.defrouter[i].if_index == ifindex) {
 121                         /* sanity check */
 122                         if (!IN6_IS_ADDR_LINKLOCAL(&dr.defrouter[i].rtaddr)) {
 123                                 warnmsg(LOG_ERR, __func__,
 124                                     "default router list contains a "
 125                                     "non-link-local address(%s)",
 126                                     inet_ntop(AF_INET6,
 127                                     &dr.defrouter[i].rtaddr,
 128                                     ntopbuf, INET6_ADDRSTRLEN));
 129                                 continue; /* ignore the address */
 130                         }
 131                         sendprobe(&dr.defrouter[i].rtaddr, ifinfo);
 132                 }
 133         }
 134
 135 closeandend:
 136         close(s);
 137 }
 138
 139 static void
 140 sendprobe(struct in6_addr *addr, struct ifinfo *ifinfo)
 141 {
 142         char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
 143         struct sockaddr_in6 sa6_probe;
 144         struct in6_pktinfo *pi;
 145         struct cmsghdr *cm;
 146         u_int32_t ifindex = ifinfo->sdl->sdl_index;
 147         int hoplimit = 1;
 148
 149         memset(&sa6_probe, 0, sizeof(sa6_probe));
 150         sa6_probe.sin6_family = AF_INET6;
 151         sa6_probe.sin6_len = sizeof(sa6_probe);
 152         sa6_probe.sin6_addr = *addr;
 153         sa6_probe.sin6_scope_id = ifinfo->linkid;
 154
 155         sndmhdr.msg_name = (caddr_t)&sa6_probe;
 156         sndmhdr.msg_iov[0].iov_base = NULL;
 157         sndmhdr.msg_iov[0].iov_len = 0;
 158
 159         cm = CMSG_FIRSTHDR(&sndmhdr);
 160         /* specify the outgoing interface */
 161         cm->cmsg_level = IPPROTO_IPV6;
 162         cm->cmsg_type = IPV6_PKTINFO;
 163         cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
 164         pi = (struct in6_pktinfo *)CMSG_DATA(cm);
 165         memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));       /*XXX*/
 166         pi->ipi6_ifindex = ifindex;
 167
 168         /* specify the hop limit of the packet for safety */
 169         cm = CMSG_NXTHDR(&sndmhdr, cm);
 170         cm->cmsg_level = IPPROTO_IPV6;
 171         cm->cmsg_type = IPV6_HOPLIMIT;
 172         cm->cmsg_len = CMSG_LEN(sizeof(int));
 173         memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
 174
 175         warnmsg(LOG_DEBUG, __func__, "probe a router %s on %s",
 176             inet_ntop(AF_INET6, addr, ntopbuf, INET6_ADDRSTRLEN),
 177             if_indextoname(ifindex, ifnamebuf));
 178
 179         if (sendmsg(probesock, &sndmhdr, 0))
 180                 warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s",
 181                     if_indextoname(ifindex, ifnamebuf), strerror(errno));
 182 }