probe.c revision 66776 
1/*	$KAME$	*/
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 66776 2000-10-06 23:46:52Z kris $
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#if defined(__FreeBSD__) && __FreeBSD__ >= 3
43#include <net/if_var.h>
44#endif /* __FreeBSD__ >= 3 */
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 __P((struct in6_addr *addr, int ifindex));
65
66
67int
68probe_init()
69{
70	int scmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
71		CMSG_SPACE(sizeof(int));
72	static u_char *sndcmsgbuf = NULL;
73
74	if (sndcmsgbuf == NULL &&
75	    (sndcmsgbuf = (u_char *)malloc(scmsglen)) == NULL) {
76		warnmsg(LOG_ERR, __FUNCTION__, "malloc failed");
77		return(-1);
78	}
79
80	if ((probesock = socket(AF_INET6, SOCK_RAW, IPPROTO_NONE)) < 0) {
81		warnmsg(LOG_ERR, __FUNCTION__, "socket: %s", strerror(errno));
82		return(-1);
83	}
84
85	/* make the socket send-only */
86	if (shutdown(probesock, 0)) {
87		warnmsg(LOG_ERR, __FUNCTION__, "shutdown: %s", strerror(errno));
88		return(-1);
89	}
90
91	/* initialize msghdr for sending packets */
92	sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
93	sndmhdr.msg_iov = sndiov;
94	sndmhdr.msg_iovlen = 1;
95	sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
96	sndmhdr.msg_controllen = scmsglen;
97
98	return(0);
99}
100
101/*
102 * Probe if each router in the default router list is still alive.
103 */
104void
105defrouter_probe(int ifindex)
106{
107	struct in6_drlist dr;
108	int s, i;
109	u_char ntopbuf[INET6_ADDRSTRLEN];
110
111	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
112		warnmsg(LOG_ERR, __FUNCTION__, "socket: %s", strerror(errno));
113		return;
114	}
115	bzero(&dr, sizeof(dr));
116	strcpy(dr.ifname, "lo0"); /* dummy interface */
117	if (ioctl(s, SIOCGDRLST_IN6, (caddr_t)&dr) < 0) {
118		warnmsg(LOG_ERR, __FUNCTION__, "ioctl(SIOCGDRLST_IN6): %s",
119		       strerror(errno));
120		goto closeandend;
121	}
122
123	for(i = 0; dr.defrouter[i].if_index && i < PRLSTSIZ; i++) {
124		if (ifindex && dr.defrouter[i].if_index == ifindex) {
125			/* sanity check */
126			if (!IN6_IS_ADDR_LINKLOCAL(&dr.defrouter[i].rtaddr)) {
127				warnmsg(LOG_ERR, __FUNCTION__,
128					"default router list contains a "
129					"non-linklocal address(%s)",
130				       inet_ntop(AF_INET6,
131						 &dr.defrouter[i].rtaddr,
132						 ntopbuf, INET6_ADDRSTRLEN));
133				continue; /* ignore the address */
134			}
135			sendprobe(&dr.defrouter[i].rtaddr,
136				  dr.defrouter[i].if_index);
137		}
138	}
139
140  closeandend:
141	close(s);
142	return;
143}
144
145static void
146sendprobe(struct in6_addr *addr, int ifindex)
147{
148	struct sockaddr_in6 sa6_probe;
149	struct in6_pktinfo *pi;
150	struct cmsghdr *cm;
151	u_char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];;
152
153	bzero(&sa6_probe, sizeof(sa6_probe));
154	sa6_probe.sin6_family = AF_INET6;
155	sa6_probe.sin6_len = sizeof(sa6_probe);
156	sa6_probe.sin6_addr = *addr;
157
158	sndmhdr.msg_name = (caddr_t)&sa6_probe;
159	sndmhdr.msg_iov[0].iov_base = NULL;
160	sndmhdr.msg_iov[0].iov_len = 0;
161
162	cm = CMSG_FIRSTHDR(&sndmhdr);
163	/* specify the outgoing interface */
164	cm->cmsg_level = IPPROTO_IPV6;
165	cm->cmsg_type = IPV6_PKTINFO;
166	cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
167	pi = (struct in6_pktinfo *)CMSG_DATA(cm);
168	memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));	/*XXX*/
169	pi->ipi6_ifindex = ifindex;
170
171	/* specify the hop limit of the packet for safety */
172	{
173		int hoplimit = 1;
174
175		cm = CMSG_NXTHDR(&sndmhdr, cm);
176		cm->cmsg_level = IPPROTO_IPV6;
177		cm->cmsg_type = IPV6_HOPLIMIT;
178		cm->cmsg_len = CMSG_LEN(sizeof(int));
179		memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
180	}
181
182	warnmsg(LOG_DEBUG, __FUNCTION__, "probe a router %s on %s",
183	       inet_ntop(AF_INET6, addr, ntopbuf, INET6_ADDRSTRLEN),
184	       if_indextoname(ifindex, ifnamebuf));
185
186	if (sendmsg(probesock, &sndmhdr, 0))
187		warnmsg(LOG_ERR, __FUNCTION__, "sendmsg on %s: %s",
188			if_indextoname(ifindex, ifnamebuf), strerror(errno));
189
190	return;
191}
192