xref: /freebsd/usr.sbin/rtadvd/rrenum.c (revision 7431dfd4580e850375fe5478d92ec770344db098) 
1 /*	$FreeBSD$	*/
2 /*	$KAME: rrenum.c,v 1.12 2002/06/10 19:59:47 itojun Exp $	*/
3 
4 /*
5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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 #include <sys/types.h>
33 #include <sys/param.h>
34 #include <sys/ioctl.h>
35 #include <sys/socket.h>
36 #include <sys/sysctl.h>
37 
38 #include <net/if.h>
39 #include <net/if_dl.h>
40 #include <net/if_var.h>
41 #include <net/route.h>
42 #include <netinet/in.h>
43 #include <netinet/in_var.h>
44 #include <netinet/icmp6.h>
45 
46 #include <arpa/inet.h>
47 
48 #include <errno.h>
49 #include <netdb.h>
50 #include <string.h>
51 #include <stdlib.h>
52 #include <time.h>
53 #include <syslog.h>
54 #include "rtadvd.h"
55 #include "rrenum.h"
56 #include "if.h"
57 
58 #define	RR_ISSET_SEGNUM(segnum_bits, segnum) \
59 	((((segnum_bits)[(segnum) >> 5]) & (1 << ((segnum) & 31))) != 0)
60 #define	RR_SET_SEGNUM(segnum_bits, segnum) \
61 	(((segnum_bits)[(segnum) >> 5]) |= (1 << ((segnum) & 31)))
62 
63 struct rr_operation {
64 	u_long	rro_seqnum;
65 	u_long	rro_segnum_bits[8];
66 };
67 
68 static struct rr_operation rro;
69 static int rr_rcvifindex;
70 static int rrcmd2pco[RPM_PCO_MAX] = {
71 	0,
72 	SIOCAIFPREFIX_IN6,
73 	SIOCCIFPREFIX_IN6,
74 	SIOCSGIFPREFIX_IN6
75 };
76 static int s = -1;
77 
78 /*
79  * Check validity of a Prefix Control Operation(PCO).
80  * return 0 on success, 1 on failure.
81  */
82 static int
83 rr_pco_check(int len, struct rr_pco_match *rpm)
84 {
85 	struct rr_pco_use *rpu, *rpulim;
86 	int checklen;
87 
88 	/* rpm->rpm_len must be (4N * 3) as router-renum-05.txt */
89 	if ((rpm->rpm_len - 3) < 0 || /* must be at least 3 */
90 	    (rpm->rpm_len - 3) & 0x3) { /* must be multiple of 4 */
91 		syslog(LOG_WARNING, "<%s> rpm_len %d is not 4N * 3",
92 		    __func__, rpm->rpm_len);
93 		return (1);
94 	}
95 	/* rpm->rpm_code must be valid value */
96 	switch (rpm->rpm_code) {
97 	case RPM_PCO_ADD:
98 	case RPM_PCO_CHANGE:
99 	case RPM_PCO_SETGLOBAL:
100 		break;
101 	default:
102 		syslog(LOG_WARNING, "<%s> unknown rpm_code %d", __func__,
103 		    rpm->rpm_code);
104 		return (1);
105 	}
106 	/* rpm->rpm_matchlen must be 0 to 128 inclusive */
107 	if (rpm->rpm_matchlen > 128) {
108 		syslog(LOG_WARNING, "<%s> rpm_matchlen %d is over 128",
109 		    __func__, rpm->rpm_matchlen);
110 		return (1);
111 	}
112 
113 	/*
114 	 * rpu->rpu_uselen, rpu->rpu_keeplen, and sum of them must be
115 	 * between 0 and 128 inclusive
116 	 */
117 	for (rpu = (struct rr_pco_use *)(rpm + 1),
118 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
119 	     rpu < rpulim;
120 	     rpu += 1) {
121 		checklen = rpu->rpu_uselen;
122 		checklen += rpu->rpu_keeplen;
123 		/*
124 		 * omit these check, because either of rpu_uselen
125 		 * and rpu_keeplen is unsigned char
126 		 *  (128 > rpu_uselen > 0)
127 		 *  (128 > rpu_keeplen > 0)
128 		 *  (rpu_uselen + rpu_keeplen > 0)
129 		 */
130 		if (checklen > 128) {
131 			syslog(LOG_WARNING, "<%s> sum of rpu_uselen %d and"
132 			    " rpu_keeplen %d is %d(over 128)",
133 			    __func__, rpu->rpu_uselen, rpu->rpu_keeplen,
134 			    rpu->rpu_uselen + rpu->rpu_keeplen);
135 			return (1);
136 		}
137 	}
138 	return (0);
139 }
140 
141 static void
142 do_use_prefix(int len, struct rr_pco_match *rpm,
143 	struct in6_rrenumreq *irr, int ifindex)
144 {
145 	struct rr_pco_use *rpu, *rpulim;
146 	struct rainfo *rai;
147 	struct ifinfo *ifi;
148 	struct prefix *pfx;
149 
150 	rpu = (struct rr_pco_use *)(rpm + 1);
151 	rpulim = (struct rr_pco_use *)((char *)rpm + len);
152 
153 	if (rpu == rpulim) {	/* no use prefix */
154 		if (rpm->rpm_code == RPM_PCO_ADD)
155 			return;
156 
157 		irr->irr_u_uselen = 0;
158 		irr->irr_u_keeplen = 0;
159 		irr->irr_raf_mask_onlink = 0;
160 		irr->irr_raf_mask_auto = 0;
161 		irr->irr_vltime = 0;
162 		irr->irr_pltime = 0;
163 		memset(&irr->irr_flags, 0, sizeof(irr->irr_flags));
164 		irr->irr_useprefix.sin6_len = 0; /* let it mean, no addition */
165 		irr->irr_useprefix.sin6_family = 0;
166 		irr->irr_useprefix.sin6_addr = in6addr_any;
167 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
168 		    errno != EADDRNOTAVAIL)
169 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
170 			    strerror(errno));
171 		return;
172 	}
173 
174 	for (rpu = (struct rr_pco_use *)(rpm + 1),
175 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
176 	     rpu < rpulim;
177 	     rpu += 1) {
178 		/* init in6_rrenumreq fields */
179 		irr->irr_u_uselen = rpu->rpu_uselen;
180 		irr->irr_u_keeplen = rpu->rpu_keeplen;
181 		irr->irr_raf_mask_onlink =
182 		    !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK);
183 		irr->irr_raf_mask_auto =
184 		    !!(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_AUTO);
185 		irr->irr_vltime = ntohl(rpu->rpu_vltime);
186 		irr->irr_pltime = ntohl(rpu->rpu_pltime);
187 		irr->irr_raf_onlink =
188 		    (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK) == 0 ?
189 		    0 : 1;
190 		irr->irr_raf_auto =
191 		    (rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_AUTO) == 0 ?
192 		    0 : 1;
193 		irr->irr_rrf_decrvalid =
194 		    (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRVLTIME) == 0 ?
195 		    0 : 1;
196 		irr->irr_rrf_decrprefd =
197 		    (rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRPLTIME) == 0 ?
198 		    0 : 1;
199 		irr->irr_useprefix.sin6_len = sizeof(irr->irr_useprefix);
200 		irr->irr_useprefix.sin6_family = AF_INET6;
201 		irr->irr_useprefix.sin6_addr = rpu->rpu_prefix;
202 
203 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
204 		    errno != EADDRNOTAVAIL)
205 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
206 			    strerror(errno));
207 
208 		/* very adhoc: should be rewritten */
209 		if (rpm->rpm_code == RPM_PCO_CHANGE &&
210 		    IN6_ARE_ADDR_EQUAL(&rpm->rpm_prefix, &rpu->rpu_prefix) &&
211 		    rpm->rpm_matchlen == rpu->rpu_uselen &&
212 		    rpu->rpu_uselen == rpu->rpu_keeplen) {
213 			ifi = if_indextoifinfo(ifindex);
214 			if (ifi == NULL || ifi->ifi_rainfo == NULL)
215 				continue; /* non-advertising IF */
216 			rai = ifi->ifi_rainfo;
217 
218 			TAILQ_FOREACH(pfx, &rai->rai_prefix, pfx_next) {
219 				struct timespec now;
220 
221 				if (prefix_match(&pfx->pfx_prefix,
222 				    pfx->pfx_prefixlen, &rpm->rpm_prefix,
223 				    rpm->rpm_matchlen)) {
224 					/* change parameters */
225 					pfx->pfx_validlifetime =
226 					    ntohl(rpu->rpu_vltime);
227 					pfx->pfx_preflifetime =
228 					    ntohl(rpu->rpu_pltime);
229 					if (irr->irr_rrf_decrvalid) {
230 						clock_gettime(CLOCK_MONOTONIC_FAST,
231 						    &now);
232 						pfx->pfx_vltimeexpire =
233 						    now.tv_sec +
234 						    pfx->pfx_validlifetime;
235 					} else
236 						pfx->pfx_vltimeexpire = 0;
237 					if (irr->irr_rrf_decrprefd) {
238 						clock_gettime(CLOCK_MONOTONIC_FAST,
239 						    &now);
240 						pfx->pfx_pltimeexpire =
241 						    now.tv_sec +
242 						    pfx->pfx_preflifetime;
243 					} else
244 						pfx->pfx_pltimeexpire = 0;
245 				}
246 			}
247 		}
248 	}
249 }
250 
251 /*
252  * process a Prefix Control Operation(PCO).
253  * return 0 on success, 1 on failure
254  */
255 static int
256 do_pco(struct icmp6_router_renum *rr, int len, struct rr_pco_match *rpm)
257 {
258 	int ifindex = 0;
259 	struct in6_rrenumreq irr;
260 	struct ifinfo *ifi;
261 
262 	if ((rr_pco_check(len, rpm) != 0))
263 		return (1);
264 
265 	if (s == -1 && (s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
266 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
267 		    strerror(errno));
268 		exit(1);
269 	}
270 
271 	memset(&irr, 0, sizeof(irr));
272 	irr.irr_origin = PR_ORIG_RR;
273 	irr.irr_m_len = rpm->rpm_matchlen;
274 	irr.irr_m_minlen = rpm->rpm_minlen;
275 	irr.irr_m_maxlen = rpm->rpm_maxlen;
276 	irr.irr_matchprefix.sin6_len = sizeof(irr.irr_matchprefix);
277 	irr.irr_matchprefix.sin6_family = AF_INET6;
278 	irr.irr_matchprefix.sin6_addr = rpm->rpm_prefix;
279 
280 	while (if_indextoname(++ifindex, irr.irr_name)) {
281 		ifi = if_indextoifinfo(ifindex);
282 		if (ifi == NULL) {
283 			syslog(LOG_ERR, "<%s> ifindex not found.",
284 			    __func__);
285 			return (1);
286 		}
287 		/*
288 		 * if ICMP6_RR_FLAGS_FORCEAPPLY(A flag) is 0 and
289 		 * IFF_UP is off, the interface is not applied
290 		 */
291 		if ((rr->rr_flags & ICMP6_RR_FLAGS_FORCEAPPLY) == 0 &&
292 		    (ifi->ifi_flags & IFF_UP) == 0)
293 			continue;
294 		/* TODO: interface scope check */
295 		do_use_prefix(len, rpm, &irr, ifindex);
296 	}
297 	if (errno == ENXIO)
298 		return (0);
299 	else if (errno) {
300 		syslog(LOG_ERR, "<%s> if_indextoname: %s", __func__,
301 		    strerror(errno));
302 		return (1);
303 	}
304 	return (0);
305 }
306 
307 /*
308  * call do_pco() for each Prefix Control Operations(PCOs) in a received
309  * Router Renumbering Command packet.
310  * return 0 on success, 1 on failure
311  */
312 static int
313 do_rr(int len, struct icmp6_router_renum *rr)
314 {
315 	struct rr_pco_match *rpm;
316 	char *cp, *lim;
317 
318 	lim = (char *)rr + len;
319 	cp = (char *)(rr + 1);
320 	len -= sizeof(struct icmp6_router_renum);
321 
322 	update_ifinfo(&ifilist, UPDATE_IFINFO_ALL);
323 
324 	while (cp < lim) {
325 		int rpmlen;
326 
327 		rpm = (struct rr_pco_match *)cp;
328 		if ((size_t)len < sizeof(struct rr_pco_match)) {
329 		    tooshort:
330 			syslog(LOG_ERR, "<%s> pkt too short. left len = %d. "
331 			    "garbage at end of pkt?", __func__, len);
332 			return (1);
333 		}
334 		rpmlen = rpm->rpm_len << 3;
335 		if (len < rpmlen)
336 			goto tooshort;
337 
338 		if (do_pco(rr, rpmlen, rpm)) {
339 			syslog(LOG_WARNING, "<%s> invalid PCO", __func__);
340 			goto next;
341 		}
342 
343 	    next:
344 		cp += rpmlen;
345 		len -= rpmlen;
346 	}
347 
348 	return (0);
349 }
350 
351 /*
352  * check validity of a router renumbering command packet
353  * return 0 on success, 1 on failure
354  */
355 static int
356 rr_command_check(int len, struct icmp6_router_renum *rr, struct in6_addr *from,
357 	struct in6_addr *dst)
358 {
359 	u_char ntopbuf[INET6_ADDRSTRLEN];
360 
361 	/* omit rr minimal length check. hope kernel have done it. */
362 	/* rr_command length check */
363 	if ((size_t)len < (sizeof(struct icmp6_router_renum) +
364 	    sizeof(struct rr_pco_match))) {
365 		syslog(LOG_ERR,	"<%s> rr_command len %d is too short",
366 		    __func__, len);
367 		return (1);
368 	}
369 
370 	/* destination check. only for multicast. omit unicast check. */
371 	if (IN6_IS_ADDR_MULTICAST(dst) && !IN6_IS_ADDR_MC_LINKLOCAL(dst) &&
372 	    !IN6_IS_ADDR_MC_SITELOCAL(dst)) {
373 		syslog(LOG_ERR,	"<%s> dst mcast addr %s is illegal",
374 		    __func__,
375 		    inet_ntop(AF_INET6, dst, ntopbuf, sizeof(ntopbuf)));
376 		return (1);
377 	}
378 
379 	/* seqnum and segnum check */
380 	if (rro.rro_seqnum > rr->rr_seqnum) {
381 		syslog(LOG_WARNING,
382 		    "<%s> rcvd old seqnum %d from %s",
383 		    __func__, (u_int32_t)ntohl(rr->rr_seqnum),
384 		   inet_ntop(AF_INET6, from, ntopbuf, sizeof(ntopbuf)));
385 		return (1);
386 	}
387 	if (rro.rro_seqnum == rr->rr_seqnum &&
388 	    (rr->rr_flags & ICMP6_RR_FLAGS_TEST) == 0 &&
389 	    RR_ISSET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum)) {
390 		if ((rr->rr_flags & ICMP6_RR_FLAGS_REQRESULT) != 0)
391 			syslog(LOG_WARNING,
392 			    "<%s> rcvd duped segnum %d from %s",
393 			    __func__, rr->rr_segnum, inet_ntop(AF_INET6, from,
394 				ntopbuf, sizeof(ntopbuf)));
395 		return (0);
396 	}
397 
398 	/* update seqnum */
399 	if (rro.rro_seqnum != rr->rr_seqnum) {
400 		/* then must be "<" */
401 
402 		/* init rro_segnum_bits */
403 		memset(rro.rro_segnum_bits, 0,
404 		    sizeof(rro.rro_segnum_bits));
405 	}
406 	rro.rro_seqnum = rr->rr_seqnum;
407 
408 	return (0);
409 }
410 
411 static void
412 rr_command_input(int len, struct icmp6_router_renum *rr,
413 	struct in6_addr *from, struct in6_addr *dst)
414 {
415 	/* rr_command validity check */
416 	if (rr_command_check(len, rr, from, dst))
417 		goto failed;
418 	if ((rr->rr_flags & (ICMP6_RR_FLAGS_TEST|ICMP6_RR_FLAGS_REQRESULT)) ==
419 	    ICMP6_RR_FLAGS_TEST)
420 		return;
421 
422 	/* do router renumbering */
423 	if (do_rr(len, rr))
424 		goto failed;
425 
426 	/* update segnum */
427 	RR_SET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum);
428 
429 	return;
430 
431     failed:
432 	syslog(LOG_ERR, "<%s> received RR was invalid", __func__);
433 	return;
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 	return;
503 }
504