rtsol.c revision 273415 
1/*	$KAME: rtsol.c,v 1.27 2003/10/05 00:09:36 itojun Exp $	*/
2
3/*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Copyright (C) 2011 Hiroki Sato
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD: releng/10.0/usr.sbin/rtsold/rtsol.c 273415 2014-10-21 20:21:10Z delphij $
33 */
34
35#include <sys/param.h>
36#include <sys/socket.h>
37#include <sys/uio.h>
38#include <sys/queue.h>
39#include <sys/wait.h>
40#include <sys/stat.h>
41
42#include <net/if.h>
43#include <net/route.h>
44#include <net/if_dl.h>
45
46#define	__BSD_VISIBLE	1	/* IN6ADDR_LINKLOCAL_ALLROUTERS_INIT */
47#include <netinet/in.h>
48#undef 	__BSD_VISIBLE
49#include <netinet/ip6.h>
50#include <netinet6/ip6_var.h>
51#include <netinet/icmp6.h>
52
53#include <arpa/inet.h>
54
55#include <netdb.h>
56#include <time.h>
57#include <fcntl.h>
58#include <unistd.h>
59#include <stdio.h>
60#include <time.h>
61#include <err.h>
62#include <errno.h>
63#include <string.h>
64#include <stdlib.h>
65#include <syslog.h>
66#include "rtsold.h"
67
68static struct msghdr rcvmhdr;
69static struct msghdr sndmhdr;
70static struct iovec rcviov[2];
71static struct iovec sndiov[2];
72static struct sockaddr_in6 from;
73static int rcvcmsglen;
74
75int rssock;
76static char rsid[IFNAMSIZ + 1 + sizeof(DNSINFO_ORIGIN_LABEL) + 1 + NI_MAXHOST];
77struct ifinfo_head_t ifinfo_head =
78	TAILQ_HEAD_INITIALIZER(ifinfo_head);
79
80static const struct sockaddr_in6 sin6_allrouters = {
81	.sin6_len =	sizeof(sin6_allrouters),
82	.sin6_family =	AF_INET6,
83	.sin6_addr =	IN6ADDR_LINKLOCAL_ALLROUTERS_INIT,
84};
85
86static void call_script(const int, const char *const *,
87    struct script_msg_head_t *);
88static size_t dname_labeldec(char *, size_t, const char *);
89static int safefile(const char *);
90static struct ra_opt *find_raopt(struct rainfo *, int, void *, size_t);
91static int ra_opt_rdnss_dispatch(struct ifinfo *, struct rainfo *,
92    struct script_msg_head_t *, struct script_msg_head_t *);
93static char *make_rsid(const char *, const char *, struct rainfo *);
94
95#define	_ARGS_OTHER	otherconf_script, ifi->ifname
96#define	_ARGS_RESADD	resolvconf_script, "-a", rsid
97#define	_ARGS_RESDEL	resolvconf_script, "-d", rsid
98
99#define	CALL_SCRIPT(name, sm_head)					\
100	do {								\
101		const char *const sarg[] = { _ARGS_##name, NULL };	\
102		call_script(sizeof(sarg), sarg, sm_head);		\
103	} while(0)
104
105#define	ELM_MALLOC(p,error_action)					\
106	do {								\
107		p = malloc(sizeof(*p));					\
108		if (p == NULL) {					\
109			warnmsg(LOG_ERR, __func__, "malloc failed: %s", \
110				strerror(errno));			\
111			error_action;					\
112		}							\
113		memset(p, 0, sizeof(*p));				\
114	} while(0)
115
116int
117sockopen(void)
118{
119	static u_char *rcvcmsgbuf = NULL, *sndcmsgbuf = NULL;
120	int sndcmsglen, on;
121	static u_char answer[1500];
122	struct icmp6_filter filt;
123
124	sndcmsglen = rcvcmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
125	    CMSG_SPACE(sizeof(int));
126	if (rcvcmsgbuf == NULL && (rcvcmsgbuf = malloc(rcvcmsglen)) == NULL) {
127		warnmsg(LOG_ERR, __func__,
128		    "malloc for receive msghdr failed");
129		return (-1);
130	}
131	if (sndcmsgbuf == NULL && (sndcmsgbuf = malloc(sndcmsglen)) == NULL) {
132		warnmsg(LOG_ERR, __func__,
133		    "malloc for send msghdr failed");
134		return (-1);
135	}
136	if ((rssock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
137		warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
138		return (-1);
139	}
140
141	/* specify to tell receiving interface */
142	on = 1;
143	if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
144	    sizeof(on)) < 0) {
145		warnmsg(LOG_ERR, __func__, "IPV6_RECVPKTINFO: %s",
146		    strerror(errno));
147		exit(1);
148	}
149
150	/* specify to tell value of hoplimit field of received IP6 hdr */
151	on = 1;
152	if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
153	    sizeof(on)) < 0) {
154		warnmsg(LOG_ERR, __func__, "IPV6_RECVHOPLIMIT: %s",
155		    strerror(errno));
156		exit(1);
157	}
158
159	/* specfiy to accept only router advertisements on the socket */
160	ICMP6_FILTER_SETBLOCKALL(&filt);
161	ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
162	if (setsockopt(rssock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
163	    sizeof(filt)) == -1) {
164		warnmsg(LOG_ERR, __func__, "setsockopt(ICMP6_FILTER): %s",
165		    strerror(errno));
166		return(-1);
167	}
168
169	/* initialize msghdr for receiving packets */
170	rcviov[0].iov_base = (caddr_t)answer;
171	rcviov[0].iov_len = sizeof(answer);
172	rcvmhdr.msg_name = (caddr_t)&from;
173	rcvmhdr.msg_iov = rcviov;
174	rcvmhdr.msg_iovlen = 1;
175	rcvmhdr.msg_control = (caddr_t) rcvcmsgbuf;
176
177	/* initialize msghdr for sending packets */
178	sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
179	sndmhdr.msg_iov = sndiov;
180	sndmhdr.msg_iovlen = 1;
181	sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
182	sndmhdr.msg_controllen = sndcmsglen;
183
184	return (rssock);
185}
186
187void
188sendpacket(struct ifinfo *ifi)
189{
190	struct in6_pktinfo *pi;
191	struct cmsghdr *cm;
192	int hoplimit = 255;
193	ssize_t i;
194	struct sockaddr_in6 dst;
195
196	dst = sin6_allrouters;
197	dst.sin6_scope_id = ifi->linkid;
198
199	sndmhdr.msg_name = (caddr_t)&dst;
200	sndmhdr.msg_iov[0].iov_base = (caddr_t)ifi->rs_data;
201	sndmhdr.msg_iov[0].iov_len = ifi->rs_datalen;
202
203	cm = CMSG_FIRSTHDR(&sndmhdr);
204	/* specify the outgoing interface */
205	cm->cmsg_level = IPPROTO_IPV6;
206	cm->cmsg_type = IPV6_PKTINFO;
207	cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
208	pi = (struct in6_pktinfo *)(void *)CMSG_DATA(cm);
209	memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));	/*XXX*/
210	pi->ipi6_ifindex = ifi->sdl->sdl_index;
211
212	/* specify the hop limit of the packet */
213	cm = CMSG_NXTHDR(&sndmhdr, cm);
214	cm->cmsg_level = IPPROTO_IPV6;
215	cm->cmsg_type = IPV6_HOPLIMIT;
216	cm->cmsg_len = CMSG_LEN(sizeof(int));
217	memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
218
219	warnmsg(LOG_DEBUG, __func__,
220	    "send RS on %s, whose state is %d",
221	    ifi->ifname, ifi->state);
222	i = sendmsg(rssock, &sndmhdr, 0);
223	if (i < 0 || (size_t)i != ifi->rs_datalen) {
224		/*
225		 * ENETDOWN is not so serious, especially when using several
226		 * network cards on a mobile node. We ignore it.
227		 */
228		if (errno != ENETDOWN || dflag > 0)
229			warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s",
230			    ifi->ifname, strerror(errno));
231	}
232
233	/* update counter */
234	ifi->probes++;
235}
236
237void
238rtsol_input(int s)
239{
240	char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
241	int l, ifindex = 0, *hlimp = NULL;
242	ssize_t msglen;
243	struct in6_pktinfo *pi = NULL;
244	struct ifinfo *ifi = NULL;
245	struct ra_opt *rao = NULL;
246	struct icmp6_hdr *icp;
247	struct nd_router_advert *nd_ra;
248	struct cmsghdr *cm;
249	struct rainfo *rai;
250	char *raoptp;
251	char *p;
252	struct in6_addr *addr;
253	struct nd_opt_hdr *ndo;
254	struct nd_opt_rdnss *rdnss;
255	struct nd_opt_dnssl *dnssl;
256	size_t len;
257	char nsbuf[INET6_ADDRSTRLEN + 1 + IFNAMSIZ + 1];
258	char dname[NI_MAXHOST];
259	struct timespec now;
260	struct timespec lifetime;
261	int newent_rai;
262	int newent_rao;
263
264	/* get message.  namelen and controllen must always be initialized. */
265	rcvmhdr.msg_namelen = sizeof(from);
266	rcvmhdr.msg_controllen = rcvcmsglen;
267	if ((msglen = recvmsg(s, &rcvmhdr, 0)) < 0) {
268		warnmsg(LOG_ERR, __func__, "recvmsg: %s", strerror(errno));
269		return;
270	}
271
272	/* extract optional information via Advanced API */
273	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&rcvmhdr); cm;
274	    cm = (struct cmsghdr *)CMSG_NXTHDR(&rcvmhdr, cm)) {
275		if (cm->cmsg_level == IPPROTO_IPV6 &&
276		    cm->cmsg_type == IPV6_PKTINFO &&
277		    cm->cmsg_len == CMSG_LEN(sizeof(struct in6_pktinfo))) {
278			pi = (struct in6_pktinfo *)(void *)(CMSG_DATA(cm));
279			ifindex = pi->ipi6_ifindex;
280		}
281		if (cm->cmsg_level == IPPROTO_IPV6 &&
282		    cm->cmsg_type == IPV6_HOPLIMIT &&
283		    cm->cmsg_len == CMSG_LEN(sizeof(int)))
284			hlimp = (int *)(void *)CMSG_DATA(cm);
285	}
286
287	if (ifindex == 0) {
288		warnmsg(LOG_ERR, __func__,
289		    "failed to get receiving interface");
290		return;
291	}
292	if (hlimp == NULL) {
293		warnmsg(LOG_ERR, __func__,
294		    "failed to get receiving hop limit");
295		return;
296	}
297
298	if ((size_t)msglen < sizeof(struct nd_router_advert)) {
299		warnmsg(LOG_INFO, __func__,
300		    "packet size(%zd) is too short", msglen);
301		return;
302	}
303
304	icp = (struct icmp6_hdr *)rcvmhdr.msg_iov[0].iov_base;
305
306	if (icp->icmp6_type != ND_ROUTER_ADVERT) {
307		/*
308		 * this should not happen because we configured a filter
309		 * that only passes RAs on the receiving socket.
310		 */
311		warnmsg(LOG_ERR, __func__,
312		    "invalid icmp type(%d) from %s on %s", icp->icmp6_type,
313		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
314			sizeof(ntopbuf)),
315		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
316		return;
317	}
318
319	if (icp->icmp6_code != 0) {
320		warnmsg(LOG_INFO, __func__,
321		    "invalid icmp code(%d) from %s on %s", icp->icmp6_code,
322		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
323			sizeof(ntopbuf)),
324		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
325		return;
326	}
327
328	if (*hlimp != 255) {
329		warnmsg(LOG_INFO, __func__,
330		    "invalid RA with hop limit(%d) from %s on %s",
331		    *hlimp,
332		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
333			sizeof(ntopbuf)),
334		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
335		return;
336	}
337
338	if (pi && !IN6_IS_ADDR_LINKLOCAL(&from.sin6_addr)) {
339		warnmsg(LOG_INFO, __func__,
340		    "invalid RA with non link-local source from %s on %s",
341		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
342			sizeof(ntopbuf)),
343		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
344		return;
345	}
346
347	/* xxx: more validation? */
348
349	if ((ifi = find_ifinfo(pi->ipi6_ifindex)) == NULL) {
350		warnmsg(LOG_INFO, __func__,
351		    "received RA from %s on an unexpected IF(%s)",
352		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
353			sizeof(ntopbuf)),
354		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
355		return;
356	}
357
358	warnmsg(LOG_DEBUG, __func__,
359	    "received RA from %s on %s, state is %d",
360	    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf, sizeof(ntopbuf)),
361	    ifi->ifname, ifi->state);
362
363	nd_ra = (struct nd_router_advert *)icp;
364
365	/*
366	 * Process the "O bit."
367	 * If the value of OtherConfigFlag changes from FALSE to TRUE, the
368	 * host should invoke the stateful autoconfiguration protocol,
369	 * requesting information.
370	 * [RFC 2462 Section 5.5.3]
371	 */
372	if (((nd_ra->nd_ra_flags_reserved) & ND_RA_FLAG_OTHER) &&
373	    !ifi->otherconfig) {
374		warnmsg(LOG_DEBUG, __func__,
375		    "OtherConfigFlag on %s is turned on", ifi->ifname);
376		ifi->otherconfig = 1;
377		CALL_SCRIPT(OTHER, NULL);
378	}
379	clock_gettime(CLOCK_MONOTONIC_FAST, &now);
380	newent_rai = 0;
381	rai = find_rainfo(ifi, &from);
382	if (rai == NULL) {
383		ELM_MALLOC(rai, exit(1));
384		rai->rai_ifinfo = ifi;
385		TAILQ_INIT(&rai->rai_ra_opt);
386		rai->rai_saddr.sin6_family = AF_INET6;
387		rai->rai_saddr.sin6_len = sizeof(rai->rai_saddr);
388		memcpy(&rai->rai_saddr.sin6_addr, &from.sin6_addr,
389		    sizeof(rai->rai_saddr.sin6_addr));
390		newent_rai = 1;
391	}
392
393#define	RA_OPT_NEXT_HDR(x)	(struct nd_opt_hdr *)((char *)x + \
394				(((struct nd_opt_hdr *)x)->nd_opt_len * 8))
395	/* Process RA options. */
396	warnmsg(LOG_DEBUG, __func__, "Processing RA");
397	raoptp = (char *)icp + sizeof(struct nd_router_advert);
398	while (raoptp < (char *)icp + msglen) {
399		ndo = (struct nd_opt_hdr *)raoptp;
400		warnmsg(LOG_DEBUG, __func__, "ndo = %p", raoptp);
401		warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_type = %d",
402		    ndo->nd_opt_type);
403		warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_len = %d",
404		    ndo->nd_opt_len);
405
406		switch (ndo->nd_opt_type) {
407		case ND_OPT_RDNSS:
408			rdnss = (struct nd_opt_rdnss *)raoptp;
409
410			/* Optlen sanity check (Section 5.3.1 in RFC 6106) */
411			if (rdnss->nd_opt_rdnss_len < 3) {
412				warnmsg(LOG_INFO, __func__,
413		    			"too short RDNSS option"
414					"in RA from %s was ignored.",
415					inet_ntop(AF_INET6, &from.sin6_addr,
416					    ntopbuf, sizeof(ntopbuf)));
417				break;
418			}
419
420			addr = (struct in6_addr *)(void *)(raoptp + sizeof(*rdnss));
421			while ((char *)addr < (char *)RA_OPT_NEXT_HDR(raoptp)) {
422				if (inet_ntop(AF_INET6, addr, ntopbuf,
423					sizeof(ntopbuf)) == NULL) {
424					warnmsg(LOG_INFO, __func__,
425		    			    "an invalid address in RDNSS option"
426					    " in RA from %s was ignored.",
427					    inet_ntop(AF_INET6, &from.sin6_addr,
428						ntopbuf, sizeof(ntopbuf)));
429					addr++;
430					continue;
431				}
432				if (IN6_IS_ADDR_LINKLOCAL(addr))
433					/* XXX: % has to be escaped here */
434					l = snprintf(nsbuf, sizeof(nsbuf),
435					    "%s%c%s", ntopbuf,
436					    SCOPE_DELIMITER,
437					    ifi->ifname);
438				else
439					l = snprintf(nsbuf, sizeof(nsbuf),
440					    "%s", ntopbuf);
441				if (l < 0 || (size_t)l >= sizeof(nsbuf)) {
442					warnmsg(LOG_ERR, __func__,
443					    "address copying error in "
444					    "RDNSS option: %d.", l);
445					addr++;
446					continue;
447				}
448				warnmsg(LOG_DEBUG, __func__, "nsbuf = %s",
449				    nsbuf);
450
451				newent_rao = 0;
452				rao = find_raopt(rai, ndo->nd_opt_type, nsbuf,
453				    strlen(nsbuf));
454				if (rao == NULL) {
455					ELM_MALLOC(rao, break);
456					rao->rao_type = ndo->nd_opt_type;
457					rao->rao_len = strlen(nsbuf);
458					rao->rao_msg = strdup(nsbuf);
459					if (rao->rao_msg == NULL) {
460						warnmsg(LOG_ERR, __func__,
461						    "strdup failed: %s",
462						    strerror(errno));
463						free(rao);
464						addr++;
465						continue;
466					}
467					newent_rao = 1;
468				}
469				/* Set expiration timer */
470				memset(&rao->rao_expire, 0,
471				    sizeof(rao->rao_expire));
472				memset(&lifetime, 0, sizeof(lifetime));
473				lifetime.tv_sec =
474				    ntohl(rdnss->nd_opt_rdnss_lifetime);
475				TS_ADD(&now, &lifetime, &rao->rao_expire);
476
477				if (newent_rao)
478					TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
479					    rao, rao_next);
480				addr++;
481			}
482			break;
483		case ND_OPT_DNSSL:
484			dnssl = (struct nd_opt_dnssl *)raoptp;
485
486			/* Optlen sanity check (Section 5.3.1 in RFC 6106) */
487			if (dnssl->nd_opt_dnssl_len < 2) {
488				warnmsg(LOG_INFO, __func__,
489		    			"too short DNSSL option"
490					"in RA from %s was ignored.",
491					inet_ntop(AF_INET6, &from.sin6_addr,
492					    ntopbuf, sizeof(ntopbuf)));
493				break;
494			}
495
496			/*
497			 * Ensure NUL-termination in DNSSL in case of
498			 * malformed field.
499			 */
500			p = (char *)RA_OPT_NEXT_HDR(raoptp);
501			*(p - 1) = '\0';
502
503			p = raoptp + sizeof(*dnssl);
504			while (1 < (len = dname_labeldec(dname, sizeof(dname),
505			    p))) {
506				/* length == 1 means empty string */
507				warnmsg(LOG_DEBUG, __func__, "dname = %s",
508				    dname);
509
510				newent_rao = 0;
511				rao = find_raopt(rai, ndo->nd_opt_type, dname,
512				    strlen(dname));
513				if (rao == NULL) {
514					ELM_MALLOC(rao, break);
515					rao->rao_type = ndo->nd_opt_type;
516					rao->rao_len = strlen(dname);
517					rao->rao_msg = strdup(dname);
518					if (rao->rao_msg == NULL) {
519						warnmsg(LOG_ERR, __func__,
520						    "strdup failed: %s",
521						    strerror(errno));
522						free(rao);
523						addr++;
524						continue;
525					}
526					newent_rao = 1;
527				}
528				/* Set expiration timer */
529				memset(&rao->rao_expire, 0,
530				    sizeof(rao->rao_expire));
531				memset(&lifetime, 0, sizeof(lifetime));
532				lifetime.tv_sec =
533				    ntohl(dnssl->nd_opt_dnssl_lifetime);
534				TS_ADD(&now, &lifetime, &rao->rao_expire);
535
536				if (newent_rao)
537					TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
538					    rao, rao_next);
539				p += len;
540			}
541			break;
542		default:
543			/* nothing to do for other options */
544			break;
545		}
546		raoptp = (char *)RA_OPT_NEXT_HDR(raoptp);
547	}
548	if (newent_rai)
549		TAILQ_INSERT_TAIL(&ifi->ifi_rainfo, rai, rai_next);
550
551	ra_opt_handler(ifi);
552	ifi->racnt++;
553
554	switch (ifi->state) {
555	case IFS_IDLE:		/* should be ignored */
556	case IFS_DELAY:		/* right? */
557		break;
558	case IFS_PROBE:
559		ifi->state = IFS_IDLE;
560		ifi->probes = 0;
561		rtsol_timer_update(ifi);
562		break;
563	}
564}
565
566static char resstr_ns_prefix[] = "nameserver ";
567static char resstr_sh_prefix[] = "search ";
568static char resstr_nl[] = "\n";
569static char resstr_sp[] = " ";
570
571int
572ra_opt_handler(struct ifinfo *ifi)
573{
574	struct ra_opt *rao;
575	struct rainfo *rai;
576	struct script_msg *smp1, *smp2, *smp3;
577	struct timespec now;
578	struct script_msg_head_t sm_rdnss_head =
579	    TAILQ_HEAD_INITIALIZER(sm_rdnss_head);
580	struct script_msg_head_t sm_dnssl_head =
581	    TAILQ_HEAD_INITIALIZER(sm_dnssl_head);
582
583	int dcount, dlen;
584
585	dcount = 0;
586	dlen = strlen(resstr_sh_prefix) + strlen(resstr_nl);
587	clock_gettime(CLOCK_MONOTONIC_FAST, &now);
588
589	/*
590	 * All options from multiple RAs with the same or different
591	 * source addresses on a single interface will be gathered and
592	 * handled, not overridden.  [RFC 4861 6.3.4]
593	 */
594	TAILQ_FOREACH(rai, &ifi->ifi_rainfo, rai_next) {
595		TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
596			switch (rao->rao_type) {
597			case ND_OPT_RDNSS:
598				if (TS_CMP(&now, &rao->rao_expire, >)) {
599					warnmsg(LOG_INFO, __func__,
600					    "expired rdnss entry: %s",
601					    (char *)rao->rao_msg);
602					break;
603				}
604				ELM_MALLOC(smp1, continue);
605				ELM_MALLOC(smp2, goto free1);
606				ELM_MALLOC(smp3, goto free2);
607				smp1->sm_msg = resstr_ns_prefix;
608				TAILQ_INSERT_TAIL(&sm_rdnss_head, smp1,
609				    sm_next);
610				smp2->sm_msg = rao->rao_msg;
611				TAILQ_INSERT_TAIL(&sm_rdnss_head, smp2,
612				    sm_next);
613				smp3->sm_msg = resstr_nl;
614				TAILQ_INSERT_TAIL(&sm_rdnss_head, smp3,
615				    sm_next);
616				ifi->ifi_rdnss = IFI_DNSOPT_STATE_RECEIVED;
617
618				break;
619			case ND_OPT_DNSSL:
620				if (TS_CMP(&now, &rao->rao_expire, >)) {
621					warnmsg(LOG_INFO, __func__,
622					    "expired dnssl entry: %s",
623					    (char *)rao->rao_msg);
624					break;
625				}
626				dcount++;
627				/* Check resolv.conf(5) restrictions. */
628				if (dcount > 6) {
629					warnmsg(LOG_INFO, __func__,
630					    "dnssl entry exceeding maximum count (%d>6)"
631					    ": %s", dcount, (char *)rao->rao_msg);
632					break;
633				}
634				if (256 < dlen + strlen(rao->rao_msg) +
635				    strlen(resstr_sp)) {
636					warnmsg(LOG_INFO, __func__,
637					    "dnssl entry exceeding maximum length "
638					    "(>256): %s", (char *)rao->rao_msg);
639					break;
640				}
641				ELM_MALLOC(smp1, continue);
642				ELM_MALLOC(smp2, goto free1);
643				if (TAILQ_EMPTY(&sm_dnssl_head)) {
644					ELM_MALLOC(smp3, goto free2);
645					smp3->sm_msg = resstr_sh_prefix;
646					TAILQ_INSERT_TAIL(&sm_dnssl_head, smp3,
647					    sm_next);
648				}
649				smp1->sm_msg = rao->rao_msg;
650				TAILQ_INSERT_TAIL(&sm_dnssl_head, smp1,
651				    sm_next);
652				smp2->sm_msg = resstr_sp;
653				TAILQ_INSERT_TAIL(&sm_dnssl_head, smp2,
654				    sm_next);
655				dlen += strlen(rao->rao_msg) +
656				    strlen(resstr_sp);
657				break;
658
659				ifi->ifi_dnssl = IFI_DNSOPT_STATE_RECEIVED;
660			default:
661				break;
662			}
663			continue;
664free2:
665			free(smp2);
666free1:
667			free(smp1);
668		}
669		/* Call the script for each information source. */
670		if (uflag)
671			ra_opt_rdnss_dispatch(ifi, rai, &sm_rdnss_head,
672			    &sm_dnssl_head);
673	}
674	/* Call the script for each interface. */
675	if (!uflag)
676		ra_opt_rdnss_dispatch(ifi, NULL, &sm_rdnss_head,
677		    &sm_dnssl_head);
678	return (0);
679}
680
681char *
682make_rsid(const char *ifname, const char *origin, struct rainfo *rai)
683{
684	char hbuf[NI_MAXHOST];
685
686	if (rai == NULL)
687		sprintf(rsid, "%s:%s", ifname, origin);
688	else {
689		if (!IN6_IS_ADDR_LINKLOCAL(&rai->rai_saddr.sin6_addr))
690			return (NULL);
691		if (getnameinfo((struct sockaddr *)&rai->rai_saddr,
692			rai->rai_saddr.sin6_len, hbuf, sizeof(hbuf), NULL, 0,
693			NI_NUMERICHOST) != 0)
694			return (NULL);
695		sprintf(rsid, "%s:%s:[%s]", ifname, origin, hbuf);
696	}
697	warnmsg(LOG_DEBUG, __func__, "rsid = [%s]", rsid);
698	return (rsid);
699}
700
701int
702ra_opt_rdnss_dispatch(struct ifinfo *ifi,
703    struct rainfo *rai,
704    struct script_msg_head_t *sm_rdnss_head,
705    struct script_msg_head_t *sm_dnssl_head)
706{
707	const char *r;
708	struct script_msg *smp1;
709	int error;
710
711	error = 0;
712	/* Add \n for DNSSL list. */
713	if (!TAILQ_EMPTY(sm_dnssl_head)) {
714		ELM_MALLOC(smp1, goto ra_opt_rdnss_freeit);
715		smp1->sm_msg = resstr_nl;
716		TAILQ_INSERT_TAIL(sm_dnssl_head, smp1, sm_next);
717	}
718	TAILQ_CONCAT(sm_rdnss_head, sm_dnssl_head, sm_next);
719
720	if (rai != NULL && uflag)
721		r = make_rsid(ifi->ifname, DNSINFO_ORIGIN_LABEL, rai);
722	else
723		r = make_rsid(ifi->ifname, DNSINFO_ORIGIN_LABEL, NULL);
724	if (r == NULL) {
725		warnmsg(LOG_ERR, __func__, "make_rsid() failed.  "
726		    "Script was not invoked.");
727		error = 1;
728		goto ra_opt_rdnss_freeit;
729	}
730	if (!TAILQ_EMPTY(sm_rdnss_head))
731		CALL_SCRIPT(RESADD, sm_rdnss_head);
732	else if (ifi->ifi_rdnss == IFI_DNSOPT_STATE_RECEIVED ||
733	    ifi->ifi_dnssl == IFI_DNSOPT_STATE_RECEIVED) {
734		CALL_SCRIPT(RESDEL, NULL);
735		ifi->ifi_rdnss = IFI_DNSOPT_STATE_NOINFO;
736		ifi->ifi_dnssl = IFI_DNSOPT_STATE_NOINFO;
737	}
738
739ra_opt_rdnss_freeit:
740	/* Clear script message queue. */
741	if (!TAILQ_EMPTY(sm_rdnss_head)) {
742		while ((smp1 = TAILQ_FIRST(sm_rdnss_head)) != NULL) {
743			TAILQ_REMOVE(sm_rdnss_head, smp1, sm_next);
744			free(smp1);
745		}
746	}
747	if (!TAILQ_EMPTY(sm_dnssl_head)) {
748		while ((smp1 = TAILQ_FIRST(sm_dnssl_head)) != NULL) {
749			TAILQ_REMOVE(sm_dnssl_head, smp1, sm_next);
750			free(smp1);
751		}
752	}
753	return (error);
754}
755
756static struct ra_opt *
757find_raopt(struct rainfo *rai, int type, void *msg, size_t len)
758{
759	struct ra_opt *rao;
760
761	TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
762		if (rao->rao_type == type &&
763		    rao->rao_len == strlen(msg) &&
764		    memcmp(rao->rao_msg, msg, len) == 0)
765			break;
766	}
767
768	return (rao);
769}
770
771static void
772call_script(const int argc, const char *const argv[],
773    struct script_msg_head_t *sm_head)
774{
775	const char *scriptpath;
776	int fd[2];
777	int error;
778	pid_t pid, wpid;
779
780	if ((scriptpath = argv[0]) == NULL)
781		return;
782
783	fd[0] = fd[1] = -1;
784	if (sm_head != NULL && !TAILQ_EMPTY(sm_head)) {
785		error = pipe(fd);
786		if (error) {
787			warnmsg(LOG_ERR, __func__,
788			    "failed to create a pipe: %s", strerror(errno));
789			return;
790		}
791	}
792
793	/* launch the script */
794	pid = fork();
795	if (pid < 0) {
796		warnmsg(LOG_ERR, __func__,
797		    "failed to fork: %s", strerror(errno));
798		return;
799	} else if (pid) {	/* parent */
800		int wstatus;
801
802		if (fd[0] != -1) {	/* Send message to the child if any. */
803			ssize_t len;
804			struct script_msg *smp;
805
806			close(fd[0]);
807			TAILQ_FOREACH(smp, sm_head, sm_next) {
808				len = strlen(smp->sm_msg);
809				warnmsg(LOG_DEBUG, __func__,
810				    "write to child = %s(%zd)",
811				    smp->sm_msg, len);
812				if (write(fd[1], smp->sm_msg, len) != len) {
813					warnmsg(LOG_ERR, __func__,
814					    "write to child failed: %s",
815					    strerror(errno));
816					break;
817				}
818			}
819			close(fd[1]);
820		}
821		do {
822			wpid = wait(&wstatus);
823		} while (wpid != pid && wpid > 0);
824
825		if (wpid < 0)
826			warnmsg(LOG_ERR, __func__,
827			    "wait: %s", strerror(errno));
828		else
829			warnmsg(LOG_DEBUG, __func__,
830			    "script \"%s\" terminated", scriptpath);
831	} else {		/* child */
832		int nullfd;
833		char **_argv;
834
835		if (safefile(scriptpath)) {
836			warnmsg(LOG_ERR, __func__,
837			    "script \"%s\" cannot be executed safely",
838			    scriptpath);
839			exit(1);
840		}
841		nullfd = open("/dev/null", O_RDWR);
842		if (nullfd < 0) {
843			warnmsg(LOG_ERR, __func__,
844			    "open /dev/null: %s", strerror(errno));
845			exit(1);
846		}
847		if (fd[0] != -1) {	/* Receive message from STDIN if any. */
848			close(fd[1]);
849			if (fd[0] != STDIN_FILENO) {
850				/* Connect a pipe read-end to child's STDIN. */
851				if (dup2(fd[0], STDIN_FILENO) != STDIN_FILENO) {
852					warnmsg(LOG_ERR, __func__,
853					    "dup2 STDIN: %s", strerror(errno));
854					exit(1);
855				}
856				close(fd[0]);
857			}
858		} else
859			dup2(nullfd, STDIN_FILENO);
860
861		dup2(nullfd, STDOUT_FILENO);
862		dup2(nullfd, STDERR_FILENO);
863		if (nullfd > STDERR_FILENO)
864			close(nullfd);
865
866		_argv = malloc(sizeof(*_argv) * argc);
867		if (_argv == NULL) {
868			warnmsg(LOG_ERR, __func__,
869				"malloc: %s", strerror(errno));
870			exit(1);
871		}
872		memcpy(_argv, argv, (size_t)argc);
873		execv(scriptpath, (char *const *)_argv);
874		warnmsg(LOG_ERR, __func__, "child: exec failed: %s",
875		    strerror(errno));
876		exit(1);
877	}
878
879	return;
880}
881
882static int
883safefile(const char *path)
884{
885	struct stat s;
886	uid_t myuid;
887
888	/* no setuid */
889	if (getuid() != geteuid()) {
890		warnmsg(LOG_NOTICE, __func__,
891		    "setuid'ed execution not allowed\n");
892		return (-1);
893	}
894
895	if (lstat(path, &s) != 0) {
896		warnmsg(LOG_NOTICE, __func__, "lstat failed: %s",
897		    strerror(errno));
898		return (-1);
899	}
900
901	/* the file must be owned by the running uid */
902	myuid = getuid();
903	if (s.st_uid != myuid) {
904		warnmsg(LOG_NOTICE, __func__,
905		    "%s has invalid owner uid\n", path);
906		return (-1);
907	}
908
909	switch (s.st_mode & S_IFMT) {
910	case S_IFREG:
911		break;
912	default:
913		warnmsg(LOG_NOTICE, __func__,
914		    "%s is an invalid file type 0x%o\n",
915		    path, (s.st_mode & S_IFMT));
916		return (-1);
917	}
918
919	return (0);
920}
921
922/* Decode domain name label encoding in RFC 1035 Section 3.1 */
923static size_t
924dname_labeldec(char *dst, size_t dlen, const char *src)
925{
926	size_t len;
927	const char *src_origin;
928	const char *src_last;
929	const char *dst_origin;
930
931	src_origin = src;
932	src_last = strchr(src, '\0');
933	dst_origin = dst;
934	memset(dst, '\0', dlen);
935	while (src && (len = (uint8_t)(*src++) & 0x3f) &&
936	    (src + len) <= src_last &&
937	    (dst - dst_origin < (ssize_t)dlen)) {
938		if (dst != dst_origin)
939			*dst++ = '.';
940		warnmsg(LOG_DEBUG, __func__, "labellen = %zd", len);
941		memcpy(dst, src, len);
942		src += len;
943		dst += len;
944	}
945	*dst = '\0';
946
947	/*
948	 * XXX validate that domain name only contains valid characters
949	 * for two reasons: 1) correctness, 2) we do not want to pass
950	 * possible malicious, unescaped characters like `` to a script
951	 * or program that could be exploited that way.
952	 */
953
954	return (src - src_origin);
955}
956