xref: /freebsd/usr.sbin/rtadvd/rrenum.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c) 
1 /*	$FreeBSD$	*/
2 /*	$KAME: rrenum.c,v 1.10 2001/01/21 15:32:16 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 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
40 #include <net/if_var.h>
41 #endif /* __FreeBSD__ >= 3 */
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 <string.h>
51 #include <stdlib.h>
52 #include <syslog.h>
53 #include "rtadvd.h"
54 #include "rrenum.h"
55 #include "if.h"
56 
57 #define	RR_ISSET_SEGNUM(segnum_bits, segnum) \
58 	((((segnum_bits)[(segnum) >> 5]) & (1 << ((segnum) & 31))) != 0)
59 #define	RR_SET_SEGNUM(segnum_bits, segnum) \
60 	(((segnum_bits)[(segnum) >> 5]) |= (1 << ((segnum) & 31)))
61 
62 struct rr_operation {
63 	u_long	rro_seqnum;
64 	u_long	rro_segnum_bits[8];
65 };
66 
67 static struct rr_operation rro;
68 static int rr_rcvifindex;
69 static int rrcmd2pco[RPM_PCO_MAX] = {
70 	0,
71 	SIOCAIFPREFIX_IN6,
72 	SIOCCIFPREFIX_IN6,
73 	SIOCSGIFPREFIX_IN6
74 };
75 static int s = -1;
76 
77 /*
78  * Check validity of a Prefix Control Operation(PCO).
79  * Return 0 on success, 1 on failure.
80  */
81 static int
82 rr_pco_check(int len, struct rr_pco_match *rpm)
83 {
84 	struct rr_pco_use *rpu, *rpulim;
85 	int checklen;
86 
87 	/* rpm->rpm_len must be (4N * 3) as router-renum-05.txt */
88 	if ((rpm->rpm_len - 3) < 0 || /* must be at least 3 */
89 	    (rpm->rpm_len - 3) & 0x3) { /* must be multiple of 4 */
90 		syslog(LOG_WARNING, "<%s> rpm_len %d is not 4N * 3",
91 		       __FUNCTION__, rpm->rpm_len);
92 		return 1;
93 	}
94 	/* rpm->rpm_code must be valid value */
95 	switch(rpm->rpm_code) {
96 	case RPM_PCO_ADD:
97 	case RPM_PCO_CHANGE:
98 	case RPM_PCO_SETGLOBAL:
99 		break;
100 	default:
101 		syslog(LOG_WARNING, "<%s> unknown rpm_code %d", __FUNCTION__,
102 		       rpm->rpm_code);
103 		return 1;
104 	}
105 	/* rpm->rpm_matchlen must be 0 to 128 inclusive */
106 	if (rpm->rpm_matchlen > 128) {
107 		syslog(LOG_WARNING, "<%s> rpm_matchlen %d is over 128",
108 		       __FUNCTION__, rpm->rpm_matchlen);
109 		return 1;
110 	}
111 
112 	/*
113 	 * rpu->rpu_uselen, rpu->rpu_keeplen, and sum of them must be
114 	 * between 0 and 128 inclusive
115 	 */
116 	for (rpu = (struct rr_pco_use *)(rpm + 1),
117 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
118 	     rpu < rpulim;
119 	     rpu += 1) {
120 		checklen = rpu->rpu_uselen;
121 		checklen += rpu->rpu_keeplen;
122 		/*
123 		 * omit these check, because either of rpu_uselen
124 		 * and rpu_keeplen is unsigned char
125 		 *  (128 > rpu_uselen > 0)
126 		 *  (128 > rpu_keeplen > 0)
127 		 *  (rpu_uselen + rpu_keeplen > 0)
128 		 */
129 		if (checklen > 128) {
130 			syslog(LOG_WARNING, "<%s> sum of rpu_uselen %d and"
131 			       " rpu_keeplen %d is %d(over 128)",
132 			       __FUNCTION__, rpu->rpu_uselen,
133 			       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 prefix *pp;
148 
149 	rpu = (struct rr_pco_use *)(rpm + 1);
150 	rpulim = (struct rr_pco_use *)((char *)rpm + len);
151 
152 	if (rpu == rpulim) {	/* no use prefix */
153 		if (rpm->rpm_code == RPM_PCO_ADD)
154 			return;
155 
156 		irr->irr_u_uselen = 0;
157 		irr->irr_u_keeplen = 0;
158 		irr->irr_raf_mask_onlink = 0;
159 		irr->irr_raf_mask_auto = 0;
160 		irr->irr_vltime = 0;
161 		irr->irr_pltime = 0;
162 		memset(&irr->irr_flags, 0, sizeof(irr->irr_flags));
163 		irr->irr_useprefix.sin6_len = 0; /* let it mean, no addition */
164 		irr->irr_useprefix.sin6_family = 0;
165 		irr->irr_useprefix.sin6_addr = in6addr_any;
166 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
167 		    errno != EADDRNOTAVAIL)
168 			syslog(LOG_ERR, "<%s> ioctl: %s", __FUNCTION__,
169 			       strerror(errno));
170 		return;
171 	}
172 
173 	for (rpu = (struct rr_pco_use *)(rpm + 1),
174 	     rpulim = (struct rr_pco_use *)((char *)rpm + len);
175 	     rpu < rpulim;
176 	     rpu += 1) {
177 		/* init in6_rrenumreq fields */
178 		irr->irr_u_uselen = rpu->rpu_uselen;
179 		irr->irr_u_keeplen = rpu->rpu_keeplen;
180 		irr->irr_raf_mask_onlink =
181 			(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK);
182 		irr->irr_raf_mask_auto =
183 			(rpu->rpu_ramask & ICMP6_RR_PCOUSE_RAFLAGS_AUTO);
184 		irr->irr_vltime = ntohl(rpu->rpu_vltime);
185 		irr->irr_pltime = ntohl(rpu->rpu_pltime);
186 		irr->irr_raf_onlink =
187 			(rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_ONLINK) == 0 ? 0 : 1;
188 		irr->irr_raf_auto =
189 			(rpu->rpu_raflags & ICMP6_RR_PCOUSE_RAFLAGS_AUTO) == 0 ? 0 : 1;
190 		irr->irr_rrf_decrvalid =
191 			(rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRVLTIME) == 0 ? 0 : 1;
192 		irr->irr_rrf_decrprefd =
193 			(rpu->rpu_flags & ICMP6_RR_PCOUSE_FLAGS_DECRPLTIME) == 0 ? 0 : 1;
194 		irr->irr_useprefix.sin6_len = sizeof(irr->irr_useprefix);
195 		irr->irr_useprefix.sin6_family = AF_INET6;
196 		irr->irr_useprefix.sin6_addr = rpu->rpu_prefix;
197 
198 		if (ioctl(s, rrcmd2pco[rpm->rpm_code], (caddr_t)irr) < 0 &&
199 		    errno != EADDRNOTAVAIL)
200 			syslog(LOG_ERR, "<%s> ioctl: %s", __FUNCTION__,
201 			       strerror(errno));
202 
203 		/* very adhoc: should be rewritten */
204 		if (rpm->rpm_code == RPM_PCO_CHANGE &&
205 		    IN6_ARE_ADDR_EQUAL(&rpm->rpm_prefix, &rpu->rpu_prefix) &&
206 		    rpm->rpm_matchlen == rpu->rpu_uselen &&
207 		    rpu->rpu_uselen == rpu->rpu_keeplen) {
208 			if ((rai = if_indextorainfo(ifindex)) == NULL)
209 				continue; /* non-advertising IF */
210 
211 			for (pp = rai->prefix.next; pp != &rai->prefix;
212 			     pp = pp->next) {
213 				struct timeval now;
214 
215 				if (prefix_match(&pp->prefix, pp->prefixlen,
216 						 &rpm->rpm_prefix,
217 						 rpm->rpm_matchlen)) {
218 					/* change parameters */
219 					pp->validlifetime = ntohl(rpu->rpu_vltime);
220 					pp->preflifetime = ntohl(rpu->rpu_pltime);
221 					if (irr->irr_rrf_decrvalid) {
222 						gettimeofday(&now, 0);
223 						pp->vltimeexpire =
224 							now.tv_sec + pp->validlifetime;
225 					} else
226 						pp->vltimeexpire = 0;
227 					if (irr->irr_rrf_decrprefd) {
228 						gettimeofday(&now, 0);
229 						pp->pltimeexpire =
230 							now.tv_sec + pp->preflifetime;
231 					} else
232 						pp->pltimeexpire = 0;
233 				}
234 			}
235 		}
236 	}
237 }
238 
239 /*
240  * process a Prefix Control Operation(PCO).
241  * return 0 on success, 1 on failure
242  */
243 static int
244 do_pco(struct icmp6_router_renum *rr, int len, struct rr_pco_match *rpm)
245 {
246 	int ifindex = 0;
247 	struct in6_rrenumreq irr;
248 
249 	if ((rr_pco_check(len, rpm) != NULL))
250 		return 1;
251 
252 	if (s == -1 && (s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
253 		syslog(LOG_ERR, "<%s> socket: %s", __FUNCTION__,
254 		       strerror(errno));
255 		exit(1);
256 	}
257 
258 	memset(&irr, 0, sizeof(irr));
259 	irr.irr_origin = PR_ORIG_RR;
260 	irr.irr_m_len = rpm->rpm_matchlen;
261 	irr.irr_m_minlen = rpm->rpm_minlen;
262 	irr.irr_m_maxlen = rpm->rpm_maxlen;
263 	irr.irr_matchprefix.sin6_len = sizeof(irr.irr_matchprefix);
264 	irr.irr_matchprefix.sin6_family = AF_INET6;
265 	irr.irr_matchprefix.sin6_addr = rpm->rpm_prefix;
266 
267 	while (if_indextoname(++ifindex, irr.irr_name)) {
268 		/*
269 		 * if ICMP6_RR_FLAGS_FORCEAPPLY(A flag) is 0 and IFF_UP is off,
270 		 * the interface is not applied
271 		 */
272 		if ((rr->rr_flags & ICMP6_RR_FLAGS_FORCEAPPLY) == 0 &&
273 		    (iflist[ifindex]->ifm_flags & IFF_UP) == 0)
274 			continue;
275 		/* TODO: interface scope check */
276 		do_use_prefix(len, rpm, &irr, ifindex);
277 	}
278 	if (errno == ENXIO)
279 		return 0;
280 	else if (errno) {
281 		syslog(LOG_ERR, "<%s> if_indextoname: %s", __FUNCTION__,
282 		       strerror(errno));
283 		return 1;
284 	}
285 	return 0;
286 }
287 
288 /*
289  * call do_pco() for each Prefix Control Operations(PCOs) in a received
290  * Router Renumbering Command packet.
291  * return 0 on success, 1 on failure
292  */
293 static int
294 do_rr(int len, struct icmp6_router_renum *rr)
295 {
296 	struct rr_pco_match *rpm;
297 	char *cp, *lim;
298 
299 	lim = (char *)rr + len;
300 	cp = (char *)(rr + 1);
301 	len -= sizeof(struct icmp6_router_renum);
302 
303 	/* get iflist block from kernel again, to get up-to-date information */
304 	init_iflist();
305 
306 	while (cp < lim) {
307 		int rpmlen;
308 
309 		rpm = (struct rr_pco_match *)cp;
310 		if (len < sizeof(struct rr_pco_match)) {
311 		    tooshort:
312 			syslog(LOG_ERR, "<%s> pkt too short. left len = %d. "
313 			       "gabage at end of pkt?", __FUNCTION__, len);
314 			return 1;
315 		}
316 		rpmlen = rpm->rpm_len << 3;
317 		if (len < rpmlen)
318 			goto tooshort;
319 
320 		if (do_pco(rr, rpmlen, rpm)) {
321 			syslog(LOG_WARNING, "<%s> invalid PCO", __FUNCTION__);
322 			goto next;
323 		}
324 
325 	    next:
326 		cp += rpmlen;
327 		len -= rpmlen;
328 	}
329 
330 	return 0;
331 }
332 
333 /*
334  * check validity of a router renumbering command packet
335  * return 0 on success, 1 on failure
336  */
337 static int
338 rr_command_check(int len, struct icmp6_router_renum *rr, struct in6_addr *from,
339 		 struct in6_addr *dst)
340 {
341 	u_char ntopbuf[INET6_ADDRSTRLEN];
342 
343 	/* omit rr minimal length check. hope kernel have done it. */
344 	/* rr_command length check */
345 	if (len < (sizeof(struct icmp6_router_renum) +
346 		   sizeof(struct rr_pco_match))) {
347 		syslog(LOG_ERR,	"<%s> rr_command len %d is too short",
348 		       __FUNCTION__, len);
349 		return 1;
350 	}
351 
352 	/* destination check. only for multicast. omit unicast check. */
353 	if (IN6_IS_ADDR_MULTICAST(dst) && !IN6_IS_ADDR_MC_LINKLOCAL(dst) &&
354 	    !IN6_IS_ADDR_MC_SITELOCAL(dst)) {
355 		syslog(LOG_ERR,	"<%s> dst mcast addr %s is illegal",
356 		       __FUNCTION__,
357 		       inet_ntop(AF_INET6, dst, ntopbuf, INET6_ADDRSTRLEN));
358 		return 1;
359 	}
360 
361 	/* seqnum and segnum check */
362 	if (rro.rro_seqnum > rr->rr_seqnum) {
363 		syslog(LOG_WARNING,
364 		       "<%s> rcvd old seqnum %d from %s",
365 		       __FUNCTION__, (u_int32_t)ntohl(rr->rr_seqnum),
366 		       inet_ntop(AF_INET6, from, ntopbuf, INET6_ADDRSTRLEN));
367 		return 1;
368 	}
369 	if (rro.rro_seqnum == rr->rr_seqnum &&
370 	    (rr->rr_flags & ICMP6_RR_FLAGS_TEST) == 0 &&
371 	    RR_ISSET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum)) {
372 		if ((rr->rr_flags & ICMP6_RR_FLAGS_REQRESULT) != 0)
373 			syslog(LOG_WARNING,
374 			       "<%s> rcvd duped segnum %d from %s",
375 			       __FUNCTION__, rr->rr_segnum,
376 			       inet_ntop(AF_INET6, from, ntopbuf,
377 					 INET6_ADDRSTRLEN));
378 		return 0;
379 	}
380 
381 	/* update seqnum */
382 	if (rro.rro_seqnum != rr->rr_seqnum) {
383 		/* then must be "<" */
384 
385 		/* init rro_segnum_bits */
386 		memset(rro.rro_segnum_bits, 0,
387 		       sizeof(rro.rro_segnum_bits));
388 	}
389 	rro.rro_seqnum = rr->rr_seqnum;
390 
391 	return 0;
392 }
393 
394 static void
395 rr_command_input(int len, struct icmp6_router_renum *rr,
396 		 struct in6_addr *from, struct in6_addr *dst)
397 {
398 	/* rr_command validity check */
399 	if (rr_command_check(len, rr, from, dst))
400 		goto failed;
401 	if ((rr->rr_flags & (ICMP6_RR_FLAGS_TEST|ICMP6_RR_FLAGS_REQRESULT)) ==
402 	    ICMP6_RR_FLAGS_TEST)
403 		return;
404 
405 	/* do router renumbering */
406 	if (do_rr(len, rr)) {
407 		goto failed;
408 	}
409 
410 	/* update segnum */
411 	RR_SET_SEGNUM(rro.rro_segnum_bits, rr->rr_segnum);
412 
413 	return;
414 
415     failed:
416 	syslog(LOG_ERR, "<%s> received RR was invalid", __FUNCTION__);
417 	return;
418 }
419 
420 void
421 rr_input(int len, struct icmp6_router_renum *rr, struct in6_pktinfo *pi,
422 	 struct sockaddr_in6 *from, struct in6_addr *dst)
423 {
424 	u_char ntopbuf[2][INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
425 
426 	syslog(LOG_DEBUG,
427 	       "<%s> RR received from %s to %s on %s",
428 	       __FUNCTION__,
429 	       inet_ntop(AF_INET6, &from->sin6_addr,
430 			 ntopbuf[0], INET6_ADDRSTRLEN),
431 	       inet_ntop(AF_INET6, &dst, ntopbuf[1], INET6_ADDRSTRLEN),
432 	       if_indextoname(pi->ipi6_ifindex, ifnamebuf));
433 
434 	/* packet validation based on Section 4.1 of RFC2894 */
435 	if (len < sizeof(struct icmp6_router_renum)) {
436 		syslog(LOG_NOTICE,
437 		       "<%s>: RR short message (size %d) from %s to %s on %s",
438 		       __FUNCTION__, len,
439 		       inet_ntop(AF_INET6, &from->sin6_addr,
440 				 ntopbuf[0], INET6_ADDRSTRLEN),
441 		       inet_ntop(AF_INET6, &dst, ntopbuf[1], INET6_ADDRSTRLEN),
442 		       if_indextoname(pi->ipi6_ifindex, ifnamebuf));
443 		return;
444 	}
445 
446 	/*
447 	 * If the IPv6 destination address is neither an All Routers multicast
448 	 * address [AARCH] nor one of the receiving router's unicast addresses,
449 	 * the message MUST be discarded and SHOULD be logged to network
450 	 * management.
451 	 * We rely on the kernel input routine for unicast addresses, and thus
452 	 * check multicast destinations only.
453 	 */
454 	if (IN6_IS_ADDR_MULTICAST(&pi->ipi6_addr) &&
455 	    !IN6_ARE_ADDR_EQUAL(&in6a_site_allrouters, &pi->ipi6_addr)) {
456 		syslog(LOG_NOTICE,
457 		       "<%s>: RR message with invalid destination (%s) "
458 		       "from %s on %s",
459 		       __FUNCTION__,
460 		       inet_ntop(AF_INET6, &dst, ntopbuf[0], INET6_ADDRSTRLEN),
461 		       inet_ntop(AF_INET6, &from->sin6_addr,
462 				 ntopbuf[1], INET6_ADDRSTRLEN),
463 		       if_indextoname(pi->ipi6_ifindex, ifnamebuf));
464 		return;
465 	}
466 
467 	rr_rcvifindex = pi->ipi6_ifindex;
468 
469 	switch (rr->rr_code) {
470 	case ICMP6_ROUTER_RENUMBERING_COMMAND:
471 		rr_command_input(len, rr, &from->sin6_addr, dst);
472 		/* TODO: send reply msg */
473 		break;
474 	case ICMP6_ROUTER_RENUMBERING_RESULT:
475 		/* RESULT will be processed by rrenumd */
476 		break;
477 	case ICMP6_ROUTER_RENUMBERING_SEQNUM_RESET:
478 		/* TODO: sequence number reset */
479 		break;
480 	default:
481 		syslog(LOG_ERR,	"<%s> received unknown code %d",
482 		       __FUNCTION__, rr->rr_code);
483 		break;
484 
485 	}
486 
487 	return;
488 }
489