probe.c revision 254470
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: head/usr.sbin/rtsold/probe.c 254470 2013-08-17 22:13:26Z hrs $ 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/sysctl.h> 39#include <sys/uio.h> 40#include <sys/queue.h> 41 42#include <net/if.h> 43#include <net/if_var.h> 44#include <net/if_dl.h> 45 46#include <netinet/in.h> 47#include <netinet6/in6_var.h> 48#include <netinet/icmp6.h> 49#include <netinet6/nd6.h> 50 51#include <arpa/inet.h> 52 53#include <errno.h> 54#include <unistd.h> 55#include <string.h> 56#include <syslog.h> 57#include <stdlib.h> 58 59#include "rtsold.h" 60 61static struct msghdr sndmhdr; 62static struct iovec sndiov[2]; 63static int probesock; 64static void sendprobe(struct in6_addr *, struct ifinfo *); 65 66int 67probe_init(void) 68{ 69 int scmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) + 70 CMSG_SPACE(sizeof(int)); 71 static u_char *sndcmsgbuf = NULL; 72 73 if (sndcmsgbuf == NULL && 74 (sndcmsgbuf = (u_char *)malloc(scmsglen)) == NULL) { 75 warnmsg(LOG_ERR, __func__, "malloc failed"); 76 return (-1); 77 } 78 79 if ((probesock = socket(AF_INET6, SOCK_RAW, IPPROTO_NONE)) < 0) { 80 warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno)); 81 return (-1); 82 } 83 84 /* make the socket send-only */ 85 if (shutdown(probesock, 0)) { 86 warnmsg(LOG_ERR, __func__, "shutdown: %s", strerror(errno)); 87 return (-1); 88 } 89 90 /* initialize msghdr for sending packets */ 91 sndmhdr.msg_namelen = sizeof(struct sockaddr_in6); 92 sndmhdr.msg_iov = sndiov; 93 sndmhdr.msg_iovlen = 1; 94 sndmhdr.msg_control = (caddr_t)sndcmsgbuf; 95 sndmhdr.msg_controllen = scmsglen; 96 97 return (0); 98} 99 100/* 101 * Probe if each router in the default router list is still alive. 102 */ 103void 104defrouter_probe(struct ifinfo *ifinfo) 105{ 106 struct in6_defrouter *p, *ep; 107 int ifindex, mib[4]; 108 char *buf, ntopbuf[INET6_ADDRSTRLEN]; 109 size_t l; 110 111 ifindex = ifinfo->sdl->sdl_index; 112 if (ifindex == 0) 113 return; 114 mib[0] = CTL_NET; 115 mib[1] = PF_INET6; 116 mib[2] = IPPROTO_ICMPV6; 117 mib[3] = ICMPV6CTL_ND6_DRLIST; 118 if (sysctl(mib, nitems(mib), NULL, &l, NULL, 0) < 0) { 119 warnmsg(LOG_ERR, __func__, "sysctl(ICMPV6CTL_ND6_DRLIST): %s", 120 strerror(errno)); 121 return; 122 } 123 if (l == 0) 124 return; 125 buf = malloc(l); 126 if (buf == NULL) { 127 warnmsg(LOG_ERR, __func__, "malloc(): %s", strerror(errno)); 128 return; 129 } 130 if (sysctl(mib, nitems(mib), buf, &l, NULL, 0) < 0) { 131 warnmsg(LOG_ERR, __func__, "sysctl(ICMPV6CTL_ND6_DRLIST): %s", 132 strerror(errno)); 133 free(buf); 134 return; 135 } 136 ep = (struct in6_defrouter *)(void *)(buf + l); 137 for (p = (struct in6_defrouter *)(void *)buf; p < ep; p++) { 138 if (ifindex != p->if_index) 139 continue; 140 if (!IN6_IS_ADDR_LINKLOCAL(&p->rtaddr.sin6_addr)) { 141 warnmsg(LOG_ERR, __func__, 142 "default router list contains a " 143 "non-link-local address(%s)", 144 inet_ntop(AF_INET6, &p->rtaddr.sin6_addr, ntopbuf, 145 INET6_ADDRSTRLEN)); 146 continue; /* ignore the address */ 147 } 148 sendprobe(&p->rtaddr.sin6_addr, ifinfo); 149 } 150 free(buf); 151} 152 153static void 154sendprobe(struct in6_addr *addr, struct ifinfo *ifinfo) 155{ 156 u_char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ]; 157 struct sockaddr_in6 sa6_probe; 158 struct in6_pktinfo *pi; 159 struct cmsghdr *cm; 160 u_int32_t ifindex = ifinfo->sdl->sdl_index; 161 int hoplimit = 1; 162 163 memset(&sa6_probe, 0, sizeof(sa6_probe)); 164 sa6_probe.sin6_family = AF_INET6; 165 sa6_probe.sin6_len = sizeof(sa6_probe); 166 sa6_probe.sin6_addr = *addr; 167 sa6_probe.sin6_scope_id = ifinfo->linkid; 168 169 sndmhdr.msg_name = (caddr_t)&sa6_probe; 170 sndmhdr.msg_iov[0].iov_base = NULL; 171 sndmhdr.msg_iov[0].iov_len = 0; 172 173 cm = CMSG_FIRSTHDR(&sndmhdr); 174 /* specify the outgoing interface */ 175 cm->cmsg_level = IPPROTO_IPV6; 176 cm->cmsg_type = IPV6_PKTINFO; 177 cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); 178 pi = (struct in6_pktinfo *)(void *)CMSG_DATA(cm); 179 memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr)); /*XXX*/ 180 pi->ipi6_ifindex = ifindex; 181 182 /* specify the hop limit of the packet for safety */ 183 cm = CMSG_NXTHDR(&sndmhdr, cm); 184 cm->cmsg_level = IPPROTO_IPV6; 185 cm->cmsg_type = IPV6_HOPLIMIT; 186 cm->cmsg_len = CMSG_LEN(sizeof(int)); 187 memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int)); 188 189 warnmsg(LOG_DEBUG, __func__, "probe a router %s on %s", 190 inet_ntop(AF_INET6, addr, ntopbuf, INET6_ADDRSTRLEN), 191 if_indextoname(ifindex, ifnamebuf)); 192 193 if (sendmsg(probesock, &sndmhdr, 0)) 194 warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s", 195 if_indextoname(ifindex, ifnamebuf), strerror(errno)); 196} 197