probe.c revision 118664 
1/*	$KAME: probe.c,v 1.10 2000/08/13 06:14:59 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 118664 2003-08-08 16:56:01Z ume $
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 *, int));
65
66int
67probe_init()
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	return(0);
97}
98
99/*
100 * Probe if each router in the default router list is still alive.
101 */
102void
103defrouter_probe(int ifindex)
104{
105	struct in6_drlist dr;
106	int s, i;
107	u_char ntopbuf[INET6_ADDRSTRLEN];
108
109	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
110		warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
111		return;
112	}
113	bzero(&dr, sizeof(dr));
114	strcpy(dr.ifname, "lo0"); /* 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,
134			    dr.defrouter[i].if_index);
135		}
136	}
137
138closeandend:
139	close(s);
140}
141
142static void
143sendprobe(struct in6_addr *addr, int ifindex)
144{
145	struct sockaddr_in6 sa6_probe;
146	struct in6_pktinfo *pi;
147	struct cmsghdr *cm;
148	u_char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
149	int hoplimit = 1;
150
151	bzero(&sa6_probe, 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
156	sndmhdr.msg_name = (caddr_t)&sa6_probe;
157	sndmhdr.msg_iov[0].iov_base = NULL;
158	sndmhdr.msg_iov[0].iov_len = 0;
159
160	cm = CMSG_FIRSTHDR(&sndmhdr);
161	/* specify the outgoing interface */
162	cm->cmsg_level = IPPROTO_IPV6;
163	cm->cmsg_type = IPV6_PKTINFO;
164	cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
165	pi = (struct in6_pktinfo *)CMSG_DATA(cm);
166	memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));	/*XXX*/
167	pi->ipi6_ifindex = ifindex;
168
169	/* specify the hop limit of the packet for safety */
170	cm = CMSG_NXTHDR(&sndmhdr, cm);
171	cm->cmsg_level = IPPROTO_IPV6;
172	cm->cmsg_type = IPV6_HOPLIMIT;
173	cm->cmsg_len = CMSG_LEN(sizeof(int));
174	memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
175
176	warnmsg(LOG_DEBUG, __func__, "probe a router %s on %s",
177	    inet_ntop(AF_INET6, addr, ntopbuf, INET6_ADDRSTRLEN),
178	    if_indextoname(ifindex, ifnamebuf));
179
180	if (sendmsg(probesock, &sndmhdr, 0))
181		warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s",
182		    if_indextoname(ifindex, ifnamebuf), strerror(errno));
183}
184