xref: /freebsd/usr.sbin/rtadvd/rrenum.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f) 
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_var.h>
40 #include <net/route.h>
41 #include <netinet/in.h>
42 #include <netinet/in_var.h>
43 #include <netinet/icmp6.h>
44 
45 #include <arpa/inet.h>
46 
47 #include <errno.h>
48 #include <string.h>
49 #include <stdlib.h>
50 #include <syslog.h>
51 #include "rtadvd.h"
52 #include "rrenum.h"
53 #include "if.h"
54 
55 #define	RR_ISSET_SEGNUM(segnum_bits, segnum) \
56 	((((segnum_bits)[(segnum) >> 5]) & (1 << ((segnum) & 31))) != 0)
57 #define	RR_SET_SEGNUM(segnum_bits, segnum) \
58 	(((segnum_bits)[(segnum) >> 5]) |= (1 << ((segnum) & 31)))
59 
60 struct rr_operation {
61 	u_long	rro_seqnum;
62 	u_long	rro_segnum_bits[8];
63 };
64 
65 static struct rr_operation rro;
66 static int rr_rcvifindex;
67 static int rrcmd2pco[RPM_PCO_MAX] = {
68 	0,
69 	SIOCAIFPREFIX_IN6,
70 	SIOCCIFPREFIX_IN6,
71 	SIOCSGIFPREFIX_IN6
72 };
73 static int s = -1;
74 
75 /*
76  * Check validity of a Prefix Control Operation(PCO).
77  * Return 0 on success, 1 on failure.
78  */
79 static int
80 rr_pco_check(int len, struct rr_pco_match *rpm)
81 {
82 	struct rr_pco_use *rpu, *rpulim;
83 	int checklen;
84 
85 	/* rpm->rpm_len must be (4N * 3) as router-renum-05.txt */
86 	if ((rpm->rpm_len - 3) < 0 || /* must be at least 3 */
87 	    (rpm->rpm_len - 3) & 0x3) { /* must be multiple of 4 */
88 		syslog(LOG_WARNING, "<%s> rpm_len %d is not 4N * 3",
89 		       __func__, rpm->rpm_len);
90 		return 1;
91 	}
92 	/* rpm->rpm_code must be valid value */
93 	switch (rpm->rpm_code) {
94 	case RPM_PCO_ADD:
95 	case RPM_PCO_CHANGE:
96 	case RPM_PCO_SETGLOBAL:
97 		break;
98 	default:
99 		syslog(LOG_WARNING, "<%s> unknown rpm_code %d", __func__,
100 		       rpm->rpm_code);
101 		return 1;
102 	}
103 	/* rpm->rpm_matchlen must be 0 to 128 inclusive */
104 	if (rpm->rpm_matchlen > 128) {
105 		syslog(LOG_WARNING, "<%s> rpm_matchlen %d is over 128",
106 		       __func__, rpm->rpm_matchlen);
107 		return 1;
108 	}
109 
110 	/*
111 	 * rpu->rpu_uselen, rpu->rpu_keeplen, and sum of them must be
112 	 * between 0 and 128 inclusive
113 	 */
114 	for (rpu = (struct rr_pco_use *)(rpm + 1),
115 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
116 	     rpu < rpulim;
117 	     rpu += 1) {
118 		checklen = rpu->rpu_uselen;
119 		checklen += rpu->rpu_keeplen;
120 		/*
121 		 * omit these check, because either of rpu_uselen
122 		 * and rpu_keeplen is unsigned char
123 		 *  (128 > rpu_uselen > 0)
124 		 *  (128 > rpu_keeplen > 0)
125 		 *  (rpu_uselen + rpu_keeplen > 0)
126 		 */
127 		if (checklen > 128) {
128 			syslog(LOG_WARNING, "<%s> sum of rpu_uselen %d and"
129 			       " rpu_keeplen %d is %d(over 128)",
130 			       __func__, rpu->rpu_uselen,
131 			       rpu->rpu_keeplen,
132 			       rpu->rpu_uselen + rpu->rpu_keeplen);
133 			return 1;
134 		}
135 	}
136 	return 0;
137 }
138 
139 static void
140 do_use_prefix(int len, struct rr_pco_match *rpm,
141 	      struct in6_rrenumreq *irr, int ifindex)
142 {
143 	struct rr_pco_use *rpu, *rpulim;
144 	struct rainfo *rai;
145 	struct prefix *pp;
146 
147 	rpu = (struct rr_pco_use *)(rpm + 1);
148 	rpulim = (struct rr_pco_use *)((char *)rpm + len);
149 
150 	if (rpu == rpulim) {	/* no use prefix */
151 		if (rpm->rpm_code == RPM_PCO_ADD)
152 			return;
153 
154 		irr->irr_u_uselen = 0;
155 		irr->irr_u_keeplen = 0;
156 		irr->irr_raf_mask_onlink = 0;
157 		irr->irr_raf_mask_auto = 0;
158 		irr->irr_vltime = 0;
159 		irr->irr_pltime = 0;
160 		memset(&irr->irr_flags, 0, sizeof(irr->irr_flags));
161 		irr->irr_useprefix.sin6_len = 0; /* let it mean, no addition */
162 		irr->irr_useprefix.sin6_family = 0;
163 		irr->irr_useprefix.sin6_addr = in6addr_any;
164 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
165 		    errno != EADDRNOTAVAIL)
166 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
167 			       strerror(errno));
168 		return;
169 	}
170 
171 	for (rpu = (struct rr_pco_use *)(rpm + 1),
172 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
173 	     rpu < rpulim;
174 	     rpu += 1) {
175 		/* init in6_rrenumreq fields */
176 		irr->irr_u_uselen = rpu->rpu_uselen;
177 		irr->irr_u_keeplen = rpu->rpu_keeplen;
178 		irr->irr_raf_mask_onlink =
179 			(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK);
180 		irr->irr_raf_mask_auto =
181 			(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_AUTO);
182 		irr->irr_vltime = ntohl(rpu->rpu_vltime);
183 		irr->irr_pltime = ntohl(rpu->rpu_pltime);
184 		irr->irr_raf_onlink =
185 			(rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK) == 0 ? 0 : 1;
186 		irr->irr_raf_auto =
187 			(rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_AUTO) == 0 ? 0 : 1;
188 		irr->irr_rrf_decrvalid =
189 			(rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRVLTIME) == 0 ? 0 : 1;
190 		irr->irr_rrf_decrprefd =
191 			(rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRPLTIME) == 0 ? 0 : 1;
192 		irr->irr_useprefix.sin6_len = sizeof(irr->irr_useprefix);
193 		irr->irr_useprefix.sin6_family = AF_INET6;
194 		irr->irr_useprefix.sin6_addr = rpu->rpu_prefix;
195 
196 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
197 		    errno != EADDRNOTAVAIL)
198 			syslog(LOG_ERR, "<%s> ioctl: %s", __func__,
199 			       strerror(errno));
200 
201 		/* very adhoc: should be rewritten */
202 		if (rpm->rpm_code == RPM_PCO_CHANGE &&
203 		    IN6_ARE_ADDR_EQUAL(&rpm->rpm_prefix, &rpu->rpu_prefix) &&
204 		    rpm->rpm_matchlen == rpu->rpu_uselen &&
205 		    rpu->rpu_uselen == rpu->rpu_keeplen) {
206 			if ((rai = if_indextorainfo(ifindex)) == NULL)
207 				continue; /* non-advertising IF */
208 
209 			for (pp = rai->prefix.next; pp != &rai->prefix;
210 			     pp = pp->next) {
211 				struct timeval now;
212 
213 				if (prefix_match(&pp->prefix, pp->prefixlen,
214 						 &rpm->rpm_prefix,
215 						 rpm->rpm_matchlen)) {
216 					/* change parameters */
217 					pp->validlifetime = ntohl(rpu->rpu_vltime);
218 					pp->preflifetime = ntohl(rpu->rpu_pltime);
219 					if (irr->irr_rrf_decrvalid) {
220 						gettimeofday(&now, 0);
221 						pp->vltimeexpire =
222 							now.tv_sec + pp->validlifetime;
223 					} else
224 						pp->vltimeexpire = 0;
225 					if (irr->irr_rrf_decrprefd) {
226 						gettimeofday(&now, 0);
227 						pp->pltimeexpire =
228 							now.tv_sec + pp->preflifetime;
229 					} else
230 						pp->pltimeexpire = 0;
231 				}
232 			}
233 		}
234 	}
235 }
236 
237 /*
238  * process a Prefix Control Operation(PCO).
239  * return 0 on success, 1 on failure
240  */
241 static int
242 do_pco(struct icmp6_router_renum *rr, int len, struct rr_pco_match *rpm)
243 {
244 	int ifindex = 0;
245 	struct in6_rrenumreq irr;
246 
247 	if ((rr_pco_check(len, rpm) != 0))
248 		return 1;
249 
250 	if (s == -1 && (s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
251 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
252 		       strerror(errno));
253 		exit(1);
254 	}
255 
256 	memset(&irr, 0, sizeof(irr));
257 	irr.irr_origin = PR_ORIG_RR;
258 	irr.irr_m_len = rpm->rpm_matchlen;
259 	irr.irr_m_minlen = rpm->rpm_minlen;
260 	irr.irr_m_maxlen = rpm->rpm_maxlen;
261 	irr.irr_matchprefix.sin6_len = sizeof(irr.irr_matchprefix);
262 	irr.irr_matchprefix.sin6_family = AF_INET6;
263 	irr.irr_matchprefix.sin6_addr = rpm->rpm_prefix;
264 
265 	while (if_indextoname(++ifindex, irr.irr_name)) {
266 		/*
267 		 * if ICMP6_RR_FLAGS_FORCEAPPLY(A flag) is 0 and IFF_UP is off,
268 		 * the interface is not applied
269 		 */
270 		if ((rr->rr_flags & ICMP6_RR_FLAGS_FORCEAPPLY) == 0 &&
271 		    (iflist[ifindex]->ifm_flags & IFF_UP) == 0)
272 			continue;
273 		/* TODO: interface scope check */
274 		do_use_prefix(len, rpm, &irr, ifindex);
275 	}
276 	if (errno == ENXIO)
277 		return 0;
278 	else if (errno) {
279 		syslog(LOG_ERR, "<%s> if_indextoname: %s", __func__,
280 		       strerror(errno));
281 		return 1;
282 	}
283 	return 0;
284 }
285 
286 /*
287  * call do_pco() for each Prefix Control Operations(PCOs) in a received
288  * Router Renumbering Command packet.
289  * return 0 on success, 1 on failure
290  */
291 static int
292 do_rr(int len, struct icmp6_router_renum *rr)
293 {
294 	struct rr_pco_match *rpm;
295 	char *cp, *lim;
296 
297 	lim = (char *)rr + len;
298 	cp = (char *)(rr + 1);
299 	len -= sizeof(struct icmp6_router_renum);
300 
301 	/* get iflist block from kernel again, to get up-to-date information */
302 	init_iflist();
303 
304 	while (cp < lim) {
305 		int rpmlen;
306 
307 		rpm = (struct rr_pco_match *)cp;
308 		if (len < sizeof(struct rr_pco_match)) {
309 		    tooshort:
310 			syslog(LOG_ERR, "<%s> pkt too short. left len = %d. "
311 			       "gabage at end of pkt?", __func__, len);
312 			return 1;
313 		}
314 		rpmlen = rpm->rpm_len << 3;
315 		if (len < rpmlen)
316 			goto tooshort;
317 
318 		if (do_pco(rr, rpmlen, rpm)) {
319 			syslog(LOG_WARNING, "<%s> invalid PCO", __func__);
320 			goto next;
321 		}
322 
323 	    next:
324 		cp += rpmlen;
325 		len -= rpmlen;
326 	}
327 
328 	return 0;
329 }
330 
331 /*
332  * check validity of a router renumbering command packet
333  * return 0 on success, 1 on failure
334  */
335 static int
336 rr_command_check(int len, struct icmp6_router_renum *rr, struct in6_addr *from,
337 		 struct in6_addr *dst)
338 {
339 	u_char ntopbuf[INET6_ADDRSTRLEN];
340 
341 	/* omit rr minimal length check. hope kernel have done it. */
342 	/* rr_command length check */
343 	if (len < (sizeof(struct icmp6_router_renum) +
344 		   sizeof(struct rr_pco_match))) {
345 		syslog(LOG_ERR,	"<%s> rr_command len %d is too short",
346 		       __func__, len);
347 		return 1;
348 	}
349 
350 	/* destination check. only for multicast. omit unicast check. */
351 	if (IN6_IS_ADDR_MULTICAST(dst) && !IN6_IS_ADDR_MC_LINKLOCAL(dst) &&
352 	    !IN6_IS_ADDR_MC_SITELOCAL(dst)) {
353 		syslog(LOG_ERR,	"<%s> dst mcast addr %s is illegal",
354 		       __func__,
355 		       inet_ntop(AF_INET6, dst, ntopbuf, INET6_ADDRSTRLEN));
356 		return 1;
357 	}
358 
359 	/* seqnum and segnum check */
360 	if (rro.rro_seqnum > rr->rr_seqnum) {
361 		syslog(LOG_WARNING,
362 		       "<%s> rcvd old seqnum %d from %s",
363 		       __func__, (u_int32_t)ntohl(rr->rr_seqnum),
364 		       inet_ntop(AF_INET6, from, ntopbuf, INET6_ADDRSTRLEN));
365 		return 1;
366 	}
367 	if (rro.rro_seqnum == rr->rr_seqnum &&
368 	    (rr->rr_flags & ICMP6_RR_FLAGS_TEST) == 0 &&
369 	    RR_ISSET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum)) {
370 		if ((rr->rr_flags & ICMP6_RR_FLAGS_REQRESULT) != 0)
371 			syslog(LOG_WARNING,
372 			       "<%s> rcvd duped segnum %d from %s",
373 			       __func__, rr->rr_segnum,
374 			       inet_ntop(AF_INET6, from, ntopbuf,
375 					 INET6_ADDRSTRLEN));
376 		return 0;
377 	}
378 
379 	/* update seqnum */
380 	if (rro.rro_seqnum != rr->rr_seqnum) {
381 		/* then must be "<" */
382 
383 		/* init rro_segnum_bits */
384 		memset(rro.rro_segnum_bits, 0,
385 		       sizeof(rro.rro_segnum_bits));
386 	}
387 	rro.rro_seqnum = rr->rr_seqnum;
388 
389 	return 0;
390 }
391 
392 static void
393 rr_command_input(int len, struct icmp6_router_renum *rr,
394 		 struct in6_addr *from, struct in6_addr *dst)
395 {
396 	/* rr_command validity check */
397 	if (rr_command_check(len, rr, from, dst))
398 		goto failed;
399 	if ((rr->rr_flags & (ICMP6_RR_FLAGS_TEST|ICMP6_RR_FLAGS_REQRESULT)) ==
400 	    ICMP6_RR_FLAGS_TEST)
401 		return;
402 
403 	/* do router renumbering */
404 	if (do_rr(len, rr)) {
405 		goto failed;
406 	}
407 
408 	/* update segnum */
409 	RR_SET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum);
410 
411 	return;
412 
413     failed:
414 	syslog(LOG_ERR, "<%s> received RR was invalid", __func__);
415 	return;
416 }
417 
418 void
419 rr_input(int len, struct icmp6_router_renum *rr, struct in6_pktinfo *pi,
420 	 struct sockaddr_in6 *from, struct in6_addr *dst)
421 {
422 	u_char ntopbuf[2][INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
423 
424 	syslog(LOG_DEBUG,
425 	       "<%s> RR received from %s to %s on %s",
426 	       __func__,
427 	       inet_ntop(AF_INET6, &from->sin6_addr,
428 			 ntopbuf[0], INET6_ADDRSTRLEN),
429 	       inet_ntop(AF_INET6, &dst, ntopbuf[1], INET6_ADDRSTRLEN),
430 	       if_indextoname(pi->ipi6_ifindex, ifnamebuf));
431 
432 	/* packet validation based on Section 4.1 of RFC2894 */
433 	if (len < sizeof(struct icmp6_router_renum)) {
434 		syslog(LOG_NOTICE,
435 		       "<%s>: RR short message (size %d) from %s to %s on %s",
436 		       __func__, len,
437 		       inet_ntop(AF_INET6, &from->sin6_addr,
438 				 ntopbuf[0], INET6_ADDRSTRLEN),
439 		       inet_ntop(AF_INET6, &dst, ntopbuf[1], INET6_ADDRSTRLEN),
440 		       if_indextoname(pi->ipi6_ifindex, ifnamebuf));
441 		return;
442 	}
443 
444 	/*
445 	 * If the IPv6 destination address is neither an All Routers multicast
446 	 * address [AARCH] nor one of the receiving router's unicast addresses,
447 	 * the message MUST be discarded and SHOULD be logged to network
448 	 * management.
449 	 * We rely on the kernel input routine for unicast addresses, and thus
450 	 * check multicast destinations only.
451 	 */
452 	if (IN6_IS_ADDR_MULTICAST(&pi->ipi6_addr) &&
453 	    !IN6_ARE_ADDR_EQUAL(&in6a_site_allrouters, &pi->ipi6_addr)) {
454 		syslog(LOG_NOTICE,
455 		       "<%s>: RR message with invalid destination (%s) "
456 		       "from %s on %s",
457 		       __func__,
458 		       inet_ntop(AF_INET6, &dst, ntopbuf[0], INET6_ADDRSTRLEN),
459 		       inet_ntop(AF_INET6, &from->sin6_addr,
460 				 ntopbuf[1], INET6_ADDRSTRLEN),
461 		       if_indextoname(pi->ipi6_ifindex, ifnamebuf));
462 		return;
463 	}
464 
465 	rr_rcvifindex = pi->ipi6_ifindex;
466 
467 	switch (rr->rr_code) {
468 	case ICMP6_ROUTER_RENUMBERING_COMMAND:
469 		rr_command_input(len, rr, &from->sin6_addr, dst);
470 		/* TODO: send reply msg */
471 		break;
472 	case ICMP6_ROUTER_RENUMBERING_RESULT:
473 		/* RESULT will be processed by rrenumd */
474 		break;
475 	case ICMP6_ROUTER_RENUMBERING_SEQNUM_RESET:
476 		/* TODO: sequence number reset */
477 		break;
478 	default:
479 		syslog(LOG_ERR,	"<%s> received unknown code %d",
480 		       __func__, rr->rr_code);
481 		break;
482 
483 	}
484 
485 	return;
486 }
487