probe.c revision 259065 
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: releng/10.0/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