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/11.0/usr.sbin/rtsold/probe.c 286566 2015-08-10 07:45:13Z ed $
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_dl.h>
44
45#include <netinet/in.h>
46#include <netinet6/in6_var.h>
47#include <netinet/icmp6.h>
48#include <netinet6/nd6.h>
49
50#include <arpa/inet.h>
51
52#include <errno.h>
53#include <unistd.h>
54#include <string.h>
55#include <syslog.h>
56#include <stdlib.h>
57
58#include "rtsold.h"
59
60static struct msghdr sndmhdr;
61static struct iovec sndiov[2];
62static int probesock;
63static void sendprobe(struct in6_addr *, struct ifinfo *);
64
65int
66probe_init(void)
67{
68	int scmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
69	    CMSG_SPACE(sizeof(int));
70	static u_char *sndcmsgbuf = NULL;
71
72	if (sndcmsgbuf == NULL &&
73	    (sndcmsgbuf = (u_char *)malloc(scmsglen)) == NULL) {
74		warnmsg(LOG_ERR, __func__, "malloc failed");
75		return (-1);
76	}
77
78	if ((probesock = socket(AF_INET6, SOCK_RAW, IPPROTO_NONE)) < 0) {
79		warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
80		return (-1);
81	}
82
83	/* initialize msghdr for sending packets */
84	sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
85	sndmhdr.msg_iov = sndiov;
86	sndmhdr.msg_iovlen = 1;
87	sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
88	sndmhdr.msg_controllen = scmsglen;
89
90	return (0);
91}
92
93/*
94 * Probe if each router in the default router list is still alive.
95 */
96void
97defrouter_probe(struct ifinfo *ifinfo)
98{
99	struct in6_defrouter *p, *ep;
100	int ifindex, mib[4];
101	char *buf, ntopbuf[INET6_ADDRSTRLEN];
102	size_t l;
103
104	ifindex = ifinfo->sdl->sdl_index;
105	if (ifindex == 0)
106		return;
107	mib[0] = CTL_NET;
108	mib[1] = PF_INET6;
109	mib[2] = IPPROTO_ICMPV6;
110	mib[3] = ICMPV6CTL_ND6_DRLIST;
111	if (sysctl(mib, nitems(mib), NULL, &l, NULL, 0) < 0) {
112		warnmsg(LOG_ERR, __func__, "sysctl(ICMPV6CTL_ND6_DRLIST): %s",
113		    strerror(errno));
114		return;
115	}
116	if (l == 0)
117		return;
118	buf = malloc(l);
119	if (buf == NULL) {
120		warnmsg(LOG_ERR, __func__, "malloc(): %s", strerror(errno));
121		return;
122	}
123	if (sysctl(mib, nitems(mib), buf, &l, NULL, 0) < 0) {
124		warnmsg(LOG_ERR, __func__, "sysctl(ICMPV6CTL_ND6_DRLIST): %s",
125		    strerror(errno));
126		free(buf);
127		return;
128	}
129	ep = (struct in6_defrouter *)(void *)(buf + l);
130	for (p = (struct in6_defrouter *)(void *)buf; p < ep; p++) {
131		if (ifindex != p->if_index)
132			continue;
133		if (!IN6_IS_ADDR_LINKLOCAL(&p->rtaddr.sin6_addr)) {
134			warnmsg(LOG_ERR, __func__,
135			    "default router list contains a "
136			    "non-link-local address(%s)",
137			    inet_ntop(AF_INET6, &p->rtaddr.sin6_addr, ntopbuf,
138			    INET6_ADDRSTRLEN));
139			continue; /* ignore the address */
140		}
141		sendprobe(&p->rtaddr.sin6_addr, ifinfo);
142	}
143	free(buf);
144}
145
146static void
147sendprobe(struct in6_addr *addr, struct ifinfo *ifinfo)
148{
149	u_char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
150	struct sockaddr_in6 sa6_probe;
151	struct in6_pktinfo *pi;
152	struct cmsghdr *cm;
153	u_int32_t ifindex = ifinfo->sdl->sdl_index;
154	int hoplimit = 1;
155
156	memset(&sa6_probe, 0, sizeof(sa6_probe));
157	sa6_probe.sin6_family = AF_INET6;
158	sa6_probe.sin6_len = sizeof(sa6_probe);
159	sa6_probe.sin6_addr = *addr;
160	sa6_probe.sin6_scope_id = ifinfo->linkid;
161
162	sndmhdr.msg_name = (caddr_t)&sa6_probe;
163	sndmhdr.msg_iov[0].iov_base = NULL;
164	sndmhdr.msg_iov[0].iov_len = 0;
165
166	cm = CMSG_FIRSTHDR(&sndmhdr);
167	/* specify the outgoing interface */
168	cm->cmsg_level = IPPROTO_IPV6;
169	cm->cmsg_type = IPV6_PKTINFO;
170	cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
171	pi = (struct in6_pktinfo *)(void *)CMSG_DATA(cm);
172	memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));	/*XXX*/
173	pi->ipi6_ifindex = ifindex;
174
175	/* specify the hop limit of the packet for safety */
176	cm = CMSG_NXTHDR(&sndmhdr, cm);
177	cm->cmsg_level = IPPROTO_IPV6;
178	cm->cmsg_type = IPV6_HOPLIMIT;
179	cm->cmsg_len = CMSG_LEN(sizeof(int));
180	memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
181
182	warnmsg(LOG_DEBUG, __func__, "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, __func__, "sendmsg on %s: %s",
188		    if_indextoname(ifindex, ifnamebuf), strerror(errno));
189}
190