xref: /freebsd/usr.sbin/rtadvd/rrenum.c (revision a466cc55373fc3cf86837f09da729535b57e69a1) 
1 /*	$FreeBSD$	*/
2 /*	$KAME: rrenum.c,v 1.12 2002/06/10 19:59:47 itojun Exp $	*/
3 
4 /*-
5  * SPDX-License-Identifier: BSD-3-Clause
6  *
7  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the project nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 #include <sys/types.h>
35 #include <sys/param.h>
36 #include <sys/ioctl.h>
37 #include <sys/queue.h>
38 #include <sys/socket.h>
39 #include <sys/sysctl.h>
40 
41 #include <net/if.h>
42 #include <net/if_dl.h>
43 #include <net/route.h>
44 #include <netinet/in.h>
45 #include <netinet/in_var.h>
46 #include <netinet/icmp6.h>
47 
48 #include <arpa/inet.h>
49 
50 #include <errno.h>
51 #include <netdb.h>
52 #include <string.h>
53 #include <stdlib.h>
54 #include <time.h>
55 #include <syslog.h>
56 #include "rtadvd.h"
57 #include "rrenum.h"
58 #include "if.h"
59 
60 #define	RR_ISSET_SEGNUM(segnum_bits, segnum) \
61 	((((segnum_bits)[(segnum) >> 5]) & (1 << ((segnum) & 31))) != 0)
62 #define	RR_SET_SEGNUM(segnum_bits, segnum) \
63 	(((segnum_bits)[(segnum) >> 5]) |= (1 << ((segnum) & 31)))
64 
65 struct rr_operation {
66 	u_long	rro_seqnum;
67 	u_long	rro_segnum_bits[8];
68 };
69 
70 static struct rr_operation rro;
71 static int rr_rcvifindex;
72 static int rrcmd2pco[RPM_PCO_MAX] = {
73 	0,
74 	SIOCAIFPREFIX_IN6,
75 	SIOCCIFPREFIX_IN6,
76 	SIOCSGIFPREFIX_IN6
77 };
78 static int s = -1;
79 
80 /*
81  * Check validity of a Prefix Control Operation(PCO).
82  * return 0 on success, 1 on failure.
83  */
84 static int
85 rr_pco_check(int len, struct rr_pco_match *rpm)
86 {
87 	struct rr_pco_use *rpu, *rpulim;
88 	int checklen;
89 
90 	/* rpm->rpm_len must be (4N * 3) as router-renum-05.txt */
91 	if ((rpm->rpm_len - 3) < 0 || /* must be at least 3 */
92 	    (rpm->rpm_len - 3) & 0x3) { /* must be multiple of 4 */
93 		syslog(LOG_WARNING, "<%s> rpm_len %d is not 4N * 3",
94 		    __func__, rpm->rpm_len);
95 		return (1);
96 	}
97 	/* rpm->rpm_code must be valid value */
98 	switch (rpm->rpm_code) {
99 	case RPM_PCO_ADD:
100 	case RPM_PCO_CHANGE:
101 	case RPM_PCO_SETGLOBAL:
102 		break;
103 	default:
104 		syslog(LOG_WARNING, "<%s> unknown rpm_code %d", __func__,
105 		    rpm->rpm_code);
106 		return (1);
107 	}
108 	/* rpm->rpm_matchlen must be 0 to 128 inclusive */
109 	if (rpm->rpm_matchlen > 128) {
110 		syslog(LOG_WARNING, "<%s> rpm_matchlen %d is over 128",
111 		    __func__, rpm->rpm_matchlen);
112 		return (1);
113 	}
114 
115 	/*
116 	 * rpu->rpu_uselen, rpu->rpu_keeplen, and sum of them must be
117 	 * between 0 and 128 inclusive
118 	 */
119 	for (rpu = (struct rr_pco_use *)(rpm + 1),
120 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
121 	     rpu < rpulim;
122 	     rpu += 1) {
123 		checklen = rpu->rpu_uselen;
124 		checklen += rpu->rpu_keeplen;
125 		/*
126 		 * omit these check, because either of rpu_uselen
127 		 * and rpu_keeplen is unsigned char
128 		 *  (128 > rpu_uselen > 0)
129 		 *  (128 > rpu_keeplen > 0)
130 		 *  (rpu_uselen + rpu_keeplen > 0)
131 		 */
132 		if (checklen > 128) {
133 			syslog(LOG_WARNING, "<%s> sum of rpu_uselen %d and"
134 			    " rpu_keeplen %d is %d(over 128)",
135 			    __func__, rpu->rpu_uselen, rpu->rpu_keeplen,
136 			    rpu->rpu_uselen + rpu->rpu_keeplen);
137 			return (1);
138 		}
139 	}
140 	return (0);
141 }
142 
143 static void
144 do_use_prefix(int len, struct rr_pco_match *rpm,
145 	struct in6_rrenumreq *irr, int ifindex)
146 {
147 	struct rr_pco_use *rpu, *rpulim;
148 	struct rainfo *rai;
149 	struct ifinfo *ifi;
150 	struct prefix *pfx;
151 
152 	rpu = (struct rr_pco_use *)(rpm + 1);
153 	rpulim = (struct rr_pco_use *)((char *)rpm + len);
154 
155 	if (rpu == rpulim) {	/* no use prefix */
156 		if (rpm->rpm_code == RPM_PCO_ADD)
157 			return;
158 
159 		irr->irr_u_uselen = 0;
160 		irr->irr_u_keeplen = 0;
161 		irr->irr_raf_mask_onlink = 0;
162 		irr->irr_raf_mask_auto = 0;
163 		irr->irr_vltime = 0;
164 		irr->irr_pltime = 0;
165 		memset(&irr->irr_flags, 0, sizeof(irr->irr_flags));
166 		irr->irr_useprefix.sin6_len = 0; /* let it mean, no addition */
167 		irr->irr_useprefix.sin6_family = 0;
168 		irr->irr_useprefix.sin6_addr = in6addr_any;
169 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
170 		    errno != EADDRNOTAVAIL)
171 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
172 			    strerror(errno));
173 		return;
174 	}
175 
176 	for (rpu = (struct rr_pco_use *)(rpm + 1),
177 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
178 	     rpu < rpulim;
179 	     rpu += 1) {
180 		/* init in6_rrenumreq fields */
181 		irr->irr_u_uselen = rpu->rpu_uselen;
182 		irr->irr_u_keeplen = rpu->rpu_keeplen;
183 		irr->irr_raf_mask_onlink =
184 		    !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK);
185 		irr->irr_raf_mask_auto =
186 		    !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_AUTO);
187 		irr->irr_vltime = ntohl(rpu->rpu_vltime);
188 		irr->irr_pltime = ntohl(rpu->rpu_pltime);
189 		irr->irr_raf_onlink =
190 		    (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK) == 0 ?
191 		    0 : 1;
192 		irr->irr_raf_auto =
193 		    (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_AUTO) == 0 ?
194 		    0 : 1;
195 		irr->irr_rrf_decrvalid =
196 		    (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRVLTIME) == 0 ?
197 		    0 : 1;
198 		irr->irr_rrf_decrprefd =
199 		    (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRPLTIME) == 0 ?
200 		    0 : 1;
201 		irr->irr_useprefix.sin6_len = sizeof(irr->irr_useprefix);
202 		irr->irr_useprefix.sin6_family = AF_INET6;
203 		irr->irr_useprefix.sin6_addr = rpu->rpu_prefix;
204 
205 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
206 		    errno != EADDRNOTAVAIL)
207 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
208 			    strerror(errno));
209 
210 		/* very adhoc: should be rewritten */
211 		if (rpm->rpm_code == RPM_PCO_CHANGE &&
212 		    IN6_ARE_ADDR_EQUAL(&rpm->rpm_prefix, &rpu->rpu_prefix) &&
213 		    rpm->rpm_matchlen == rpu->rpu_uselen &&
214 		    rpu->rpu_uselen == rpu->rpu_keeplen) {
215 			ifi = if_indextoifinfo(ifindex);
216 			if (ifi == NULL || ifi->ifi_rainfo == NULL)
217 				continue; /* non-advertising IF */
218 			rai = ifi->ifi_rainfo;
219 
220 			TAILQ_FOREACH(pfx, &rai->rai_prefix, pfx_next) {
221 				struct timespec now;
222 
223 				if (prefix_match(&pfx->pfx_prefix,
224 				    pfx->pfx_prefixlen, &rpm->rpm_prefix,
225 				    rpm->rpm_matchlen)) {
226 					/* change parameters */
227 					pfx->pfx_validlifetime =
228 					    ntohl(rpu->rpu_vltime);
229 					pfx->pfx_preflifetime =
230 					    ntohl(rpu->rpu_pltime);
231 					if (irr->irr_rrf_decrvalid) {
232 						clock_gettime(CLOCK_MONOTONIC_FAST,
233 						    &now);
234 						pfx->pfx_vltimeexpire =
235 						    now.tv_sec +
236 						    pfx->pfx_validlifetime;
237 					} else
238 						pfx->pfx_vltimeexpire = 0;
239 					if (irr->irr_rrf_decrprefd) {
240 						clock_gettime(CLOCK_MONOTONIC_FAST,
241 						    &now);
242 						pfx->pfx_pltimeexpire =
243 						    now.tv_sec +
244 						    pfx->pfx_preflifetime;
245 					} else
246 						pfx->pfx_pltimeexpire = 0;
247 				}
248 			}
249 		}
250 	}
251 }
252 
253 /*
254  * process a Prefix Control Operation(PCO).
255  * return 0 on success, 1 on failure
256  */
257 static int
258 do_pco(struct icmp6_router_renum *rr, int len, struct rr_pco_match *rpm)
259 {
260 	int ifindex = 0;
261 	struct in6_rrenumreq irr;
262 	struct ifinfo *ifi;
263 
264 	if ((rr_pco_check(len, rpm) != 0))
265 		return (1);
266 
267 	if (s == -1 && (s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
268 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
269 		    strerror(errno));
270 		exit(1);
271 	}
272 
273 	memset(&irr, 0, sizeof(irr));
274 	irr.irr_origin = PR_ORIG_RR;
275 	irr.irr_m_len = rpm->rpm_matchlen;
276 	irr.irr_m_minlen = rpm->rpm_minlen;
277 	irr.irr_m_maxlen = rpm->rpm_maxlen;
278 	irr.irr_matchprefix.sin6_len = sizeof(irr.irr_matchprefix);
279 	irr.irr_matchprefix.sin6_family = AF_INET6;
280 	irr.irr_matchprefix.sin6_addr = rpm->rpm_prefix;
281 
282 	while (if_indextoname(++ifindex, irr.irr_name)) {
283 		ifi = if_indextoifinfo(ifindex);
284 		if (ifi == NULL) {
285 			syslog(LOG_ERR, "<%s> ifindex not found.",
286 			    __func__);
287 			return (1);
288 		}
289 		/*
290 		 * if ICMP6_RR_FLAGS_FORCEAPPLY(A flag) is 0 and
291 		 * IFF_UP is off, the interface is not applied
292 		 */
293 		if ((rr->rr_flags & ICMP6_RR_FLAGS_FORCEAPPLY) == 0 &&
294 		    (ifi->ifi_flags & IFF_UP) == 0)
295 			continue;
296 		/* TODO: interface scope check */
297 		do_use_prefix(len, rpm, &irr, ifindex);
298 	}
299 	if (errno == ENXIO)
300 		return (0);
301 	else if (errno) {
302 		syslog(LOG_ERR, "<%s> if_indextoname: %s", __func__,
303 		    strerror(errno));
304 		return (1);
305 	}
306 	return (0);
307 }
308 
309 /*
310  * call do_pco() for each Prefix Control Operations(PCOs) in a received
311  * Router Renumbering Command packet.
312  * return 0 on success, 1 on failure
313  */
314 static int
315 do_rr(int len, struct icmp6_router_renum *rr)
316 {
317 	struct rr_pco_match *rpm;
318 	char *cp, *lim;
319 
320 	lim = (char *)rr + len;
321 	cp = (char *)(rr + 1);
322 	len -= sizeof(struct icmp6_router_renum);
323 
324 	update_ifinfo(&ifilist, UPDATE_IFINFO_ALL);
325 
326 	while (cp < lim) {
327 		int rpmlen;
328 
329 		rpm = (struct rr_pco_match *)cp;
330 		if ((size_t)len < sizeof(struct rr_pco_match)) {
331 		    tooshort:
332 			syslog(LOG_ERR, "<%s> pkt too short. left len = %d. "
333 			    "garbage at end of pkt?", __func__, len);
334 			return (1);
335 		}
336 		rpmlen = rpm->rpm_len << 3;
337 		if (len < rpmlen)
338 			goto tooshort;
339 
340 		if (do_pco(rr, rpmlen, rpm)) {
341 			syslog(LOG_WARNING, "<%s> invalid PCO", __func__);
342 			goto next;
343 		}
344 
345 	    next:
346 		cp += rpmlen;
347 		len -= rpmlen;
348 	}
349 
350 	return (0);
351 }
352 
353 /*
354  * check validity of a router renumbering command packet
355  * return 0 on success, 1 on failure
356  */
357 static int
358 rr_command_check(int len, struct icmp6_router_renum *rr, struct in6_addr *from,
359 	struct in6_addr *dst)
360 {
361 	u_char ntopbuf[INET6_ADDRSTRLEN];
362 
363 	/* omit rr minimal length check. hope kernel have done it. */
364 	/* rr_command length check */
365 	if ((size_t)len < (sizeof(struct icmp6_router_renum) +
366 	    sizeof(struct rr_pco_match))) {
367 		syslog(LOG_ERR,	"<%s> rr_command len %d is too short",
368 		    __func__, len);
369 		return (1);
370 	}
371 
372 	/* destination check. only for multicast. omit unicast check. */
373 	if (IN6_IS_ADDR_MULTICAST(dst) && !IN6_IS_ADDR_MC_LINKLOCAL(dst) &&
374 	    !IN6_IS_ADDR_MC_SITELOCAL(dst)) {
375 		syslog(LOG_ERR,	"<%s> dst mcast addr %s is illegal",
376 		    __func__,
377 		    inet_ntop(AF_INET6, dst, ntopbuf, sizeof(ntopbuf)));
378 		return (1);
379 	}
380 
381 	/* seqnum and segnum check */
382 	if (rro.rro_seqnum > rr->rr_seqnum) {
383 		syslog(LOG_WARNING,
384 		    "<%s> rcvd old seqnum %d from %s",
385 		    __func__, (u_int32_t)ntohl(rr->rr_seqnum),
386 		   inet_ntop(AF_INET6, from, ntopbuf, sizeof(ntopbuf)));
387 		return (1);
388 	}
389 	if (rro.rro_seqnum == rr->rr_seqnum &&
390 	    (rr->rr_flags & ICMP6_RR_FLAGS_TEST) == 0 &&
391 	    RR_ISSET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum)) {
392 		if ((rr->rr_flags & ICMP6_RR_FLAGS_REQRESULT) != 0)
393 			syslog(LOG_WARNING,
394 			    "<%s> rcvd duped segnum %d from %s",
395 			    __func__, rr->rr_segnum, inet_ntop(AF_INET6, from,
396 				ntopbuf, sizeof(ntopbuf)));
397 		return (0);
398 	}
399 
400 	/* update seqnum */
401 	if (rro.rro_seqnum != rr->rr_seqnum) {
402 		/* then must be "<" */
403 
404 		/* init rro_segnum_bits */
405 		memset(rro.rro_segnum_bits, 0,
406 		    sizeof(rro.rro_segnum_bits));
407 	}
408 	rro.rro_seqnum = rr->rr_seqnum;
409 
410 	return (0);
411 }
412 
413 static void
414 rr_command_input(int len, struct icmp6_router_renum *rr,
415 	struct in6_addr *from, struct in6_addr *dst)
416 {
417 	/* rr_command validity check */
418 	if (rr_command_check(len, rr, from, dst))
419 		goto failed;
420 	if ((rr->rr_flags & (ICMP6_RR_FLAGS_TEST|ICMP6_RR_FLAGS_REQRESULT)) ==
421 	    ICMP6_RR_FLAGS_TEST)
422 		return;
423 
424 	/* do router renumbering */
425 	if (do_rr(len, rr))
426 		goto failed;
427 
428 	/* update segnum */
429 	RR_SET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum);
430 
431 	return;
432 
433     failed:
434 	syslog(LOG_ERR, "<%s> received RR was invalid", __func__);
435 	return;
436 }
437 
438 void
439 rr_input(int len, struct icmp6_router_renum *rr, struct in6_pktinfo *pi,
440 	struct sockaddr_in6 *from, struct in6_addr *dst)
441 {
442 	u_char ntopbuf[2][INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
443 
444 	syslog(LOG_DEBUG,
445 	    "<%s> RR received from %s to %s on %s",
446 	    __func__,
447 	    inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf[0] ,sizeof(ntopbuf[0])),
448 	    inet_ntop(AF_INET6, &dst, ntopbuf[1], sizeof(ntopbuf[1])),
449 	    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
450 
451 	/* packet validation based on Section 4.1 of RFC2894 */
452 	if ((size_t)len < sizeof(struct icmp6_router_renum)) {
453 		syslog(LOG_NOTICE,
454 		    "<%s>: RR short message (size %d) from %s to %s on %s",
455 		    __func__, len,
456 		    inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf[0],
457 			sizeof(ntopbuf[0])),
458 		    inet_ntop(AF_INET6, &dst, ntopbuf[1], sizeof(ntopbuf[1])),
459 		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
460 		return;
461 	}
462 
463 	/*
464 	 * If the IPv6 destination address is neither an All Routers multicast
465 	 * address [AARCH] nor one of the receiving router's unicast addresses,
466 	 * the message MUST be discarded and SHOULD be logged to network
467 	 * management.
468 	 * We rely on the kernel input routine for unicast addresses, and thus
469 	 * check multicast destinations only.
470 	 */
471 	if (IN6_IS_ADDR_MULTICAST(&pi->ipi6_addr) && !IN6_ARE_ADDR_EQUAL(
472 	    &sin6_sitelocal_allrouters.sin6_addr, &pi->ipi6_addr)) {
473 		syslog(LOG_NOTICE,
474 		    "<%s>: RR message with invalid destination (%s) "
475 		    "from %s on %s",
476 		    __func__,
477 		    inet_ntop(AF_INET6, &dst, ntopbuf[0], sizeof(ntopbuf[0])),
478 		    inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf[1],
479 			      sizeof(ntopbuf[1])),
480 		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
481 		return;
482 	}
483 
484 	rr_rcvifindex = pi->ipi6_ifindex;
485 
486 	switch (rr->rr_code) {
487 	case ICMP6_ROUTER_RENUMBERING_COMMAND:
488 		rr_command_input(len, rr, &from->sin6_addr, dst);
489 		/* TODO: send reply msg */
490 		break;
491 	case ICMP6_ROUTER_RENUMBERING_RESULT:
492 		/* RESULT will be processed by rrenumd */
493 		break;
494 	case ICMP6_ROUTER_RENUMBERING_SEQNUM_RESET:
495 		/* TODO: sequence number reset */
496 		break;
497 	default:
498 		syslog(LOG_ERR,	"<%s> received unknown code %d",
499 		    __func__, rr->rr_code);
500 		break;
501 
502 	}
503 
504 	return;
505 }
506