xref: /freebsd/usr.sbin/rtadvd/rrenum.c (revision e0c4386e) 
1 /*	$KAME: rrenum.c,v 1.12 2002/06/10 19:59:47 itojun Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-3-Clause
5  *
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 #include <sys/types.h>
34 #include <sys/param.h>
35 #include <sys/ioctl.h>
36 #include <sys/queue.h>
37 #include <sys/socket.h>
38 #include <sys/sysctl.h>
39 
40 #include <net/if.h>
41 #include <net/if_dl.h>
42 #include <net/route.h>
43 #include <netinet/in.h>
44 #include <netinet/in_var.h>
45 #include <netinet/icmp6.h>
46 
47 #include <arpa/inet.h>
48 
49 #include <errno.h>
50 #include <netdb.h>
51 #include <string.h>
52 #include <stdlib.h>
53 #include <time.h>
54 #include <syslog.h>
55 #include "rtadvd.h"
56 #include "rrenum.h"
57 #include "if.h"
58 
59 #define	RR_ISSET_SEGNUM(segnum_bits, segnum) \
60 	((((segnum_bits)[(segnum) >> 5]) & (1 << ((segnum) & 31))) != 0)
61 #define	RR_SET_SEGNUM(segnum_bits, segnum) \
62 	(((segnum_bits)[(segnum) >> 5]) |= (1 << ((segnum) & 31)))
63 
64 struct rr_operation {
65 	u_long	rro_seqnum;
66 	u_long	rro_segnum_bits[8];
67 };
68 
69 static struct rr_operation rro;
70 static int rr_rcvifindex;
71 static int rrcmd2pco[RPM_PCO_MAX] = {
72 	0,
73 	SIOCAIFPREFIX_IN6,
74 	SIOCCIFPREFIX_IN6,
75 	SIOCSGIFPREFIX_IN6
76 };
77 static int s = -1;
78 
79 /*
80  * Check validity of a Prefix Control Operation(PCO).
81  * return 0 on success, 1 on failure.
82  */
83 static int
84 rr_pco_check(int len, struct rr_pco_match *rpm)
85 {
86 	struct rr_pco_use *rpu, *rpulim;
87 	int checklen;
88 
89 	/* rpm->rpm_len must be (4N * 3) as router-renum-05.txt */
90 	if ((rpm->rpm_len - 3) < 0 || /* must be at least 3 */
91 	    (rpm->rpm_len - 3) & 0x3) { /* must be multiple of 4 */
92 		syslog(LOG_WARNING, "<%s> rpm_len %d is not 4N * 3",
93 		    __func__, rpm->rpm_len);
94 		return (1);
95 	}
96 	/* rpm->rpm_code must be valid value */
97 	switch (rpm->rpm_code) {
98 	case RPM_PCO_ADD:
99 	case RPM_PCO_CHANGE:
100 	case RPM_PCO_SETGLOBAL:
101 		break;
102 	default:
103 		syslog(LOG_WARNING, "<%s> unknown rpm_code %d", __func__,
104 		    rpm->rpm_code);
105 		return (1);
106 	}
107 	/* rpm->rpm_matchlen must be 0 to 128 inclusive */
108 	if (rpm->rpm_matchlen > 128) {
109 		syslog(LOG_WARNING, "<%s> rpm_matchlen %d is over 128",
110 		    __func__, rpm->rpm_matchlen);
111 		return (1);
112 	}
113 
114 	/*
115 	 * rpu->rpu_uselen, rpu->rpu_keeplen, and sum of them must be
116 	 * between 0 and 128 inclusive
117 	 */
118 	for (rpu = (struct rr_pco_use *)(rpm + 1),
119 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
120 	     rpu < rpulim;
121 	     rpu += 1) {
122 		checklen = rpu->rpu_uselen;
123 		checklen += rpu->rpu_keeplen;
124 		/*
125 		 * omit these check, because either of rpu_uselen
126 		 * and rpu_keeplen is unsigned char
127 		 *  (128 > rpu_uselen > 0)
128 		 *  (128 > rpu_keeplen > 0)
129 		 *  (rpu_uselen + rpu_keeplen > 0)
130 		 */
131 		if (checklen > 128) {
132 			syslog(LOG_WARNING, "<%s> sum of rpu_uselen %d and"
133 			    " rpu_keeplen %d is %d(over 128)",
134 			    __func__, rpu->rpu_uselen, rpu->rpu_keeplen,
135 			    rpu->rpu_uselen + rpu->rpu_keeplen);
136 			return (1);
137 		}
138 	}
139 	return (0);
140 }
141 
142 static void
143 do_use_prefix(int len, struct rr_pco_match *rpm,
144 	struct in6_rrenumreq *irr, int ifindex)
145 {
146 	struct rr_pco_use *rpu, *rpulim;
147 	struct rainfo *rai;
148 	struct ifinfo *ifi;
149 	struct prefix *pfx;
150 
151 	rpu = (struct rr_pco_use *)(rpm + 1);
152 	rpulim = (struct rr_pco_use *)((char *)rpm + len);
153 
154 	if (rpu == rpulim) {	/* no use prefix */
155 		if (rpm->rpm_code == RPM_PCO_ADD)
156 			return;
157 
158 		irr->irr_u_uselen = 0;
159 		irr->irr_u_keeplen = 0;
160 		irr->irr_raf_mask_onlink = 0;
161 		irr->irr_raf_mask_auto = 0;
162 		irr->irr_vltime = 0;
163 		irr->irr_pltime = 0;
164 		memset(&irr->irr_flags, 0, sizeof(irr->irr_flags));
165 		irr->irr_useprefix.sin6_len = 0; /* let it mean, no addition */
166 		irr->irr_useprefix.sin6_family = 0;
167 		irr->irr_useprefix.sin6_addr = in6addr_any;
168 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
169 		    errno != EADDRNOTAVAIL)
170 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
171 			    strerror(errno));
172 		return;
173 	}
174 
175 	for (rpu = (struct rr_pco_use *)(rpm + 1),
176 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
177 	     rpu < rpulim;
178 	     rpu += 1) {
179 		/* init in6_rrenumreq fields */
180 		irr->irr_u_uselen = rpu->rpu_uselen;
181 		irr->irr_u_keeplen = rpu->rpu_keeplen;
182 		irr->irr_raf_mask_onlink =
183 		    !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK);
184 		irr->irr_raf_mask_auto =
185 		    !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_AUTO);
186 		irr->irr_vltime = ntohl(rpu->rpu_vltime);
187 		irr->irr_pltime = ntohl(rpu->rpu_pltime);
188 		irr->irr_raf_onlink =
189 		    (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK) == 0 ?
190 		    0 : 1;
191 		irr->irr_raf_auto =
192 		    (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_AUTO) == 0 ?
193 		    0 : 1;
194 		irr->irr_rrf_decrvalid =
195 		    (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRVLTIME) == 0 ?
196 		    0 : 1;
197 		irr->irr_rrf_decrprefd =
198 		    (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRPLTIME) == 0 ?
199 		    0 : 1;
200 		irr->irr_useprefix.sin6_len = sizeof(irr->irr_useprefix);
201 		irr->irr_useprefix.sin6_family = AF_INET6;
202 		irr->irr_useprefix.sin6_addr = rpu->rpu_prefix;
203 
204 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
205 		    errno != EADDRNOTAVAIL)
206 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
207 			    strerror(errno));
208 
209 		/* very adhoc: should be rewritten */
210 		if (rpm->rpm_code == RPM_PCO_CHANGE &&
211 		    IN6_ARE_ADDR_EQUAL(&rpm->rpm_prefix, &rpu->rpu_prefix) &&
212 		    rpm->rpm_matchlen == rpu->rpu_uselen &&
213 		    rpu->rpu_uselen == rpu->rpu_keeplen) {
214 			ifi = if_indextoifinfo(ifindex);
215 			if (ifi == NULL || ifi->ifi_rainfo == NULL)
216 				continue; /* non-advertising IF */
217 			rai = ifi->ifi_rainfo;
218 
219 			TAILQ_FOREACH(pfx, &rai->rai_prefix, pfx_next) {
220 				struct timespec now;
221 
222 				if (prefix_match(&pfx->pfx_prefix,
223 				    pfx->pfx_prefixlen, &rpm->rpm_prefix,
224 				    rpm->rpm_matchlen)) {
225 					/* change parameters */
226 					pfx->pfx_validlifetime =
227 					    ntohl(rpu->rpu_vltime);
228 					pfx->pfx_preflifetime =
229 					    ntohl(rpu->rpu_pltime);
230 					if (irr->irr_rrf_decrvalid) {
231 						clock_gettime(CLOCK_MONOTONIC_FAST,
232 						    &now);
233 						pfx->pfx_vltimeexpire =
234 						    now.tv_sec +
235 						    pfx->pfx_validlifetime;
236 					} else
237 						pfx->pfx_vltimeexpire = 0;
238 					if (irr->irr_rrf_decrprefd) {
239 						clock_gettime(CLOCK_MONOTONIC_FAST,
240 						    &now);
241 						pfx->pfx_pltimeexpire =
242 						    now.tv_sec +
243 						    pfx->pfx_preflifetime;
244 					} else
245 						pfx->pfx_pltimeexpire = 0;
246 				}
247 			}
248 		}
249 	}
250 }
251 
252 /*
253  * process a Prefix Control Operation(PCO).
254  * return 0 on success, 1 on failure
255  */
256 static int
257 do_pco(struct icmp6_router_renum *rr, int len, struct rr_pco_match *rpm)
258 {
259 	int ifindex = 0;
260 	struct in6_rrenumreq irr;
261 	struct ifinfo *ifi;
262 
263 	if ((rr_pco_check(len, rpm) != 0))
264 		return (1);
265 
266 	if (s == -1 && (s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
267 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
268 		    strerror(errno));
269 		exit(1);
270 	}
271 
272 	memset(&irr, 0, sizeof(irr));
273 	irr.irr_origin = PR_ORIG_RR;
274 	irr.irr_m_len = rpm->rpm_matchlen;
275 	irr.irr_m_minlen = rpm->rpm_minlen;
276 	irr.irr_m_maxlen = rpm->rpm_maxlen;
277 	irr.irr_matchprefix.sin6_len = sizeof(irr.irr_matchprefix);
278 	irr.irr_matchprefix.sin6_family = AF_INET6;
279 	irr.irr_matchprefix.sin6_addr = rpm->rpm_prefix;
280 
281 	while (if_indextoname(++ifindex, irr.irr_name)) {
282 		ifi = if_indextoifinfo(ifindex);
283 		if (ifi == NULL) {
284 			syslog(LOG_ERR, "<%s> ifindex not found.",
285 			    __func__);
286 			return (1);
287 		}
288 		/*
289 		 * if ICMP6_RR_FLAGS_FORCEAPPLY(A flag) is 0 and
290 		 * IFF_UP is off, the interface is not applied
291 		 */
292 		if ((rr->rr_flags & ICMP6_RR_FLAGS_FORCEAPPLY) == 0 &&
293 		    (ifi->ifi_flags & IFF_UP) == 0)
294 			continue;
295 		/* TODO: interface scope check */
296 		do_use_prefix(len, rpm, &irr, ifindex);
297 	}
298 	if (errno == ENXIO)
299 		return (0);
300 	else if (errno) {
301 		syslog(LOG_ERR, "<%s> if_indextoname: %s", __func__,
302 		    strerror(errno));
303 		return (1);
304 	}
305 	return (0);
306 }
307 
308 /*
309  * call do_pco() for each Prefix Control Operations(PCOs) in a received
310  * Router Renumbering Command packet.
311  * return 0 on success, 1 on failure
312  */
313 static int
314 do_rr(int len, struct icmp6_router_renum *rr)
315 {
316 	struct rr_pco_match *rpm;
317 	char *cp, *lim;
318 
319 	lim = (char *)rr + len;
320 	cp = (char *)(rr + 1);
321 	len -= sizeof(struct icmp6_router_renum);
322 
323 	update_ifinfo(&ifilist, UPDATE_IFINFO_ALL);
324 
325 	while (cp < lim) {
326 		int rpmlen;
327 
328 		rpm = (struct rr_pco_match *)cp;
329 		if ((size_t)len < sizeof(struct rr_pco_match)) {
330 		    tooshort:
331 			syslog(LOG_ERR, "<%s> pkt too short. left len = %d. "
332 			    "garbage at end of pkt?", __func__, len);
333 			return (1);
334 		}
335 		rpmlen = rpm->rpm_len << 3;
336 		if (len < rpmlen)
337 			goto tooshort;
338 
339 		if (do_pco(rr, rpmlen, rpm)) {
340 			syslog(LOG_WARNING, "<%s> invalid PCO", __func__);
341 			goto next;
342 		}
343 
344 	    next:
345 		cp += rpmlen;
346 		len -= rpmlen;
347 	}
348 
349 	return (0);
350 }
351 
352 /*
353  * check validity of a router renumbering command packet
354  * return 0 on success, 1 on failure
355  */
356 static int
357 rr_command_check(int len, struct icmp6_router_renum *rr, struct in6_addr *from,
358 	struct in6_addr *dst)
359 {
360 	u_char ntopbuf[INET6_ADDRSTRLEN];
361 
362 	/* omit rr minimal length check. hope kernel have done it. */
363 	/* rr_command length check */
364 	if ((size_t)len < (sizeof(struct icmp6_router_renum) +
365 	    sizeof(struct rr_pco_match))) {
366 		syslog(LOG_ERR,	"<%s> rr_command len %d is too short",
367 		    __func__, len);
368 		return (1);
369 	}
370 
371 	/* destination check. only for multicast. omit unicast check. */
372 	if (IN6_IS_ADDR_MULTICAST(dst) && !IN6_IS_ADDR_MC_LINKLOCAL(dst) &&
373 	    !IN6_IS_ADDR_MC_SITELOCAL(dst)) {
374 		syslog(LOG_ERR,	"<%s> dst mcast addr %s is illegal",
375 		    __func__,
376 		    inet_ntop(AF_INET6, dst, ntopbuf, sizeof(ntopbuf)));
377 		return (1);
378 	}
379 
380 	/* seqnum and segnum check */
381 	if (rro.rro_seqnum > rr->rr_seqnum) {
382 		syslog(LOG_WARNING,
383 		    "<%s> rcvd old seqnum %d from %s",
384 		    __func__, (u_int32_t)ntohl(rr->rr_seqnum),
385 		   inet_ntop(AF_INET6, from, ntopbuf, sizeof(ntopbuf)));
386 		return (1);
387 	}
388 	if (rro.rro_seqnum == rr->rr_seqnum &&
389 	    (rr->rr_flags & ICMP6_RR_FLAGS_TEST) == 0 &&
390 	    RR_ISSET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum)) {
391 		if ((rr->rr_flags & ICMP6_RR_FLAGS_REQRESULT) != 0)
392 			syslog(LOG_WARNING,
393 			    "<%s> rcvd duped segnum %d from %s",
394 			    __func__, rr->rr_segnum, inet_ntop(AF_INET6, from,
395 				ntopbuf, sizeof(ntopbuf)));
396 		return (0);
397 	}
398 
399 	/* update seqnum */
400 	if (rro.rro_seqnum != rr->rr_seqnum) {
401 		/* then must be "<" */
402 
403 		/* init rro_segnum_bits */
404 		memset(rro.rro_segnum_bits, 0,
405 		    sizeof(rro.rro_segnum_bits));
406 	}
407 	rro.rro_seqnum = rr->rr_seqnum;
408 
409 	return (0);
410 }
411 
412 static void
413 rr_command_input(int len, struct icmp6_router_renum *rr,
414 	struct in6_addr *from, struct in6_addr *dst)
415 {
416 	/* rr_command validity check */
417 	if (rr_command_check(len, rr, from, dst))
418 		goto failed;
419 	if ((rr->rr_flags & (ICMP6_RR_FLAGS_TEST|ICMP6_RR_FLAGS_REQRESULT)) ==
420 	    ICMP6_RR_FLAGS_TEST)
421 		return;
422 
423 	/* do router renumbering */
424 	if (do_rr(len, rr))
425 		goto failed;
426 
427 	/* update segnum */
428 	RR_SET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum);
429 
430 	return;
431 
432     failed:
433 	syslog(LOG_ERR, "<%s> received RR was invalid", __func__);
434 }
435 
436 void
437 rr_input(int len, struct icmp6_router_renum *rr, struct in6_pktinfo *pi,
438 	struct sockaddr_in6 *from, struct in6_addr *dst)
439 {
440 	u_char ntopbuf[2][INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
441 
442 	syslog(LOG_DEBUG,
443 	    "<%s> RR received from %s to %s on %s",
444 	    __func__,
445 	    inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf[0] ,sizeof(ntopbuf[0])),
446 	    inet_ntop(AF_INET6, &dst, ntopbuf[1], sizeof(ntopbuf[1])),
447 	    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
448 
449 	/* packet validation based on Section 4.1 of RFC2894 */
450 	if ((size_t)len < sizeof(struct icmp6_router_renum)) {
451 		syslog(LOG_NOTICE,
452 		    "<%s>: RR short message (size %d) from %s to %s on %s",
453 		    __func__, len,
454 		    inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf[0],
455 			sizeof(ntopbuf[0])),
456 		    inet_ntop(AF_INET6, &dst, ntopbuf[1], sizeof(ntopbuf[1])),
457 		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
458 		return;
459 	}
460 
461 	/*
462 	 * If the IPv6 destination address is neither an All Routers multicast
463 	 * address [AARCH] nor one of the receiving router's unicast addresses,
464 	 * the message MUST be discarded and SHOULD be logged to network
465 	 * management.
466 	 * We rely on the kernel input routine for unicast addresses, and thus
467 	 * check multicast destinations only.
468 	 */
469 	if (IN6_IS_ADDR_MULTICAST(&pi->ipi6_addr) && !IN6_ARE_ADDR_EQUAL(
470 	    &sin6_sitelocal_allrouters.sin6_addr, &pi->ipi6_addr)) {
471 		syslog(LOG_NOTICE,
472 		    "<%s>: RR message with invalid destination (%s) "
473 		    "from %s on %s",
474 		    __func__,
475 		    inet_ntop(AF_INET6, &dst, ntopbuf[0], sizeof(ntopbuf[0])),
476 		    inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf[1],
477 			      sizeof(ntopbuf[1])),
478 		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
479 		return;
480 	}
481 
482 	rr_rcvifindex = pi->ipi6_ifindex;
483 
484 	switch (rr->rr_code) {
485 	case ICMP6_ROUTER_RENUMBERING_COMMAND:
486 		rr_command_input(len, rr, &from->sin6_addr, dst);
487 		/* TODO: send reply msg */
488 		break;
489 	case ICMP6_ROUTER_RENUMBERING_RESULT:
490 		/* RESULT will be processed by rrenumd */
491 		break;
492 	case ICMP6_ROUTER_RENUMBERING_SEQNUM_RESET:
493 		/* TODO: sequence number reset */
494 		break;
495 	default:
496 		syslog(LOG_ERR,	"<%s> received unknown code %d",
497 		    __func__, rr->rr_code);
498 		break;
499 
500 	}
501 }
502