xref: /freebsd/usr.sbin/rtadvd/if.c (revision 23f282aa31e9b6fceacd449020e936e98d6f2298) 
1 /*
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 #include <sys/param.h>
33 #include <sys/socket.h>
34 #include <sys/sysctl.h>
35 #include <sys/ioctl.h>
36 #include <net/if.h>
37 #include <net/if_types.h>
38 #include <net/ethernet.h>
39 #include <net/route.h>
40 #include <net/if_dl.h>
41 #include <netinet/in.h>
42 #include <netinet/icmp6.h>
43 #include <unistd.h>
44 #include <errno.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <syslog.h>
48 #include "rtadvd.h"
49 #include "if.h"
50 
51 #define	ROUNDUP(a, size) \
52 	(((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
53 
54 #define	NEXT_SA(ap) (ap) = (struct sockaddr *) \
55 	((caddr_t)(ap) + ((ap)->sa_len ? ROUNDUP((ap)->sa_len,\
56 						 sizeof(u_long)) :\
57 			  			 sizeof(u_long)))
58 
59 struct	if_msghdr **iflist;
60 int	iflist_init_ok;
61 size_t	ifblock_size;
62 char	*ifblock;
63 
64 static void	get_iflist __P((char **buf, size_t *size));
65 static void	parse_iflist __P((struct if_msghdr ***ifmlist_p, char *buf,
66 		       size_t bufsize));
67 
68 static void
69 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
70 {
71 	int i;
72 
73 	for (i = 0; i < RTAX_MAX; i++) {
74 		if (addrs & (1 << i)) {
75 			rti_info[i] = sa;
76 			NEXT_SA(sa);
77 		}
78 		else
79 			rti_info[i] = NULL;
80 	}
81 }
82 
83 struct sockaddr_dl *
84 if_nametosdl(char *name)
85 {
86 	int mib[6] = {CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
87 	char *buf, *next, *lim;
88 	size_t len;
89 	struct if_msghdr *ifm;
90 	struct sockaddr *sa, *rti_info[RTAX_MAX];
91 	struct sockaddr_dl *sdl = NULL, *ret_sdl;
92 
93 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
94 		return(NULL);
95 	if ((buf = malloc(len)) == NULL)
96 		return(NULL);
97 	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
98 		free(buf);
99 		return(NULL);
100 	}
101 
102 	lim = buf + len;
103 	for (next = buf; next < lim; next += ifm->ifm_msglen) {
104 		ifm = (struct if_msghdr *)next;
105 		if (ifm->ifm_type == RTM_IFINFO) {
106 			sa = (struct sockaddr *)(ifm + 1);
107 			get_rtaddrs(ifm->ifm_addrs, sa, rti_info);
108 			if ((sa = rti_info[RTAX_IFP]) != NULL) {
109 				if (sa->sa_family == AF_LINK) {
110 					sdl = (struct sockaddr_dl *)sa;
111 					if (strncmp(&sdl->sdl_data[0],
112 						    name,
113 						    sdl->sdl_nlen) == 0) {
114 						break;
115 					}
116 				}
117 			}
118 		}
119 	}
120 	if (next == lim) {
121 		/* search failed */
122 		free(buf);
123 		return(NULL);
124 	}
125 
126 	if ((ret_sdl = malloc(sdl->sdl_len)) == NULL)
127 		return(NULL);
128 	memcpy((caddr_t)ret_sdl, (caddr_t)sdl, sdl->sdl_len);
129 	return(ret_sdl);
130 }
131 
132 int
133 if_getmtu(char *name)
134 {
135 	struct ifreq ifr;
136 	int s;
137 
138 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
139 		return(0);
140 
141 	ifr.ifr_addr.sa_family = AF_INET6;
142 	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
143 	if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
144 		close(s);
145 		return(0);
146 	}
147 
148 	close(s);
149 
150 	return(ifr.ifr_mtu);
151 }
152 
153 /* give interface index and its old flags, then new flags returned */
154 int
155 if_getflags(int ifindex, int oifflags)
156 {
157 	struct ifreq ifr;
158 	int s;
159 
160 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
161 		syslog(LOG_ERR, "<%s> socket: %s", __FUNCTION__,
162 		       strerror(errno));
163 		return (oifflags & ~IFF_UP);
164 	}
165 
166 	if_indextoname(ifindex, ifr.ifr_name);
167 	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
168 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
169 		       __FUNCTION__, ifr.ifr_name);
170 		close(s);
171 		return (oifflags & ~IFF_UP);
172 	}
173 	close(s);
174 	return (ifr.ifr_flags);
175 }
176 
177 #define	ROUNDUP8(a) (1 + (((a) - 1) | 7))
178 int
179 lladdropt_length(struct sockaddr_dl *sdl)
180 {
181 	switch(sdl->sdl_type) {
182 	 case IFT_ETHER:
183 		 return(ROUNDUP8(ETHER_ADDR_LEN + 2));
184 	 default:
185 		 return(0);
186 	}
187 }
188 
189 void
190 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
191 {
192 	char *addr;
193 
194 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
195 
196 	switch(sdl->sdl_type) {
197 	 case IFT_ETHER:
198 		 ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
199 		 addr = (char *)(ndopt + 1);
200 		 memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
201 		 break;
202 	 default:
203 		 syslog(LOG_ERR,
204 			"<%s> unsupported link type(%d)",
205 			__FUNCTION__, sdl->sdl_type);
206 		 exit(1);
207 	}
208 
209 	return;
210 }
211 
212 int
213 rtbuf_len()
214 {
215 	size_t len;
216 
217 	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
218 
219 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
220 		return(-1);
221 
222 	return(len);
223 }
224 
225 int
226 get_rtinfo(char *buf, size_t *len)
227 {
228 	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
229 
230 	if (sysctl(mib, 6, buf, len, NULL, 0) < 0)
231 		return(-1);
232 
233 	return(0);
234 }
235 
236 #define	FILTER_MATCH(type, filter) ((0x1 << type) & filter)
237 #define	SIN6(s) ((struct sockaddr_in6 *)(s))
238 #define	SDL(s) ((struct sockaddr_dl *)(s))
239 char *
240 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
241 {
242 	struct rt_msghdr *rtm;
243 	struct ifa_msghdr *ifam;
244 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
245 
246 	*lenp = 0;
247 	for (rtm = (struct rt_msghdr *)buf;
248 	     rtm < (struct rt_msghdr *)lim;
249 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
250 		/* just for safety */
251 		if (!rtm->rtm_msglen) {
252 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
253 				"(buf=%p lim=%p rtm=%p)", __FUNCTION__,
254 				buf, lim, rtm);
255 			break;
256 		}
257 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
258 			continue;
259 		}
260 
261 		switch (rtm->rtm_type) {
262 		case RTM_GET:
263 		case RTM_ADD:
264 		case RTM_DELETE:
265 			/* address related checks */
266 			sa = (struct sockaddr *)(rtm + 1);
267 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
268 			if ((dst = rti_info[RTAX_DST]) == NULL ||
269 			    dst->sa_family != AF_INET6)
270 				continue;
271 
272 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
273 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
274 				continue;
275 
276 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
277 			    gw->sa_family != AF_LINK)
278 				continue;
279 			if (ifindex && SDL(gw)->sdl_index != ifindex)
280 				continue;
281 
282 			if (rti_info[RTAX_NETMASK] == NULL)
283 				continue;
284 
285 			/* found */
286 			*lenp = rtm->rtm_msglen;
287 			return (char *)rtm;
288 			/* NOTREACHED */
289 		case RTM_NEWADDR:
290 		case RTM_DELADDR:
291 			ifam = (struct ifa_msghdr *)rtm;
292 
293 			/* address related checks */
294 			sa = (struct sockaddr *)(ifam + 1);
295 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
296 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
297 			    (ifa->sa_family != AF_INET &&
298 			     ifa->sa_family != AF_INET6))
299 				continue;
300 
301 			if (ifa->sa_family == AF_INET6 &&
302 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
303 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
304 				continue;
305 
306 			if (ifindex && ifam->ifam_index != ifindex)
307 				continue;
308 
309 			/* found */
310 			*lenp = ifam->ifam_msglen;
311 			return (char *)rtm;
312 			/* NOTREACHED */
313 		case RTM_IFINFO:
314 			/* found */
315 			*lenp = rtm->rtm_msglen;
316 			return (char *)rtm;
317 			/* NOTREACHED */
318 		}
319 	}
320 
321 	return (char *)rtm;
322 }
323 #undef FILTER_MATCH(type, filter)
324 
325 struct in6_addr *
326 get_addr(char *buf)
327 {
328 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
329 	struct sockaddr *sa, *rti_info[RTAX_MAX];
330 
331 	sa = (struct sockaddr *)(rtm + 1);
332 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
333 
334 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
335 }
336 
337 int
338 get_rtm_ifindex(char *buf)
339 {
340 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
341 	struct sockaddr *sa, *rti_info[RTAX_MAX];
342 
343 	sa = (struct sockaddr *)(rtm + 1);
344 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
345 
346 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
347 }
348 
349 int
350 get_ifm_ifindex(char *buf)
351 {
352 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
353 
354 	return ((int)ifm->ifm_index);
355 }
356 
357 int
358 get_ifam_ifindex(char *buf)
359 {
360 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
361 
362 	return ((int)ifam->ifam_index);
363 }
364 
365 int
366 get_ifm_flags(char *buf)
367 {
368 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
369 
370 	return (ifm->ifm_flags);
371 }
372 
373 int
374 get_prefixlen(char *buf)
375 {
376 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
377 	struct sockaddr *sa, *rti_info[RTAX_MAX];
378 	int masklen;
379 	u_char *p, *lim;
380 
381 	sa = (struct sockaddr *)(rtm + 1);
382 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
383 	sa = rti_info[RTAX_NETMASK];
384 
385 	p = (u_char *)(&SIN6(sa)->sin6_addr);
386 	lim = (u_char *)sa + sa->sa_len;
387 	for (masklen = 0; p < lim; p++) {
388 		switch (*p) {
389 		case 0xff:
390 			masklen += 8;
391 			break;
392 		case 0xfe:
393 			masklen += 7;
394 			break;
395 		case 0xfc:
396 			masklen += 6;
397 			break;
398 		case 0xf8:
399 			masklen += 5;
400 			break;
401 		case 0xf0:
402 			masklen += 4;
403 			break;
404 		case 0xe0:
405 			masklen += 3;
406 			break;
407 		case 0xc0:
408 			masklen += 2;
409 			break;
410 		case 0x80:
411 			masklen += 1;
412 			break;
413 		case 0x00:
414 			break;
415 		default:
416 			return(-1);
417 		}
418 	}
419 
420 	return(masklen);
421 }
422 
423 int
424 rtmsg_type(char *buf)
425 {
426 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
427 
428 	return(rtm->rtm_type);
429 }
430 
431 int
432 rtmsg_len(char *buf)
433 {
434 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
435 
436 	return(rtm->rtm_msglen);
437 }
438 
439 int
440 ifmsg_len(char *buf)
441 {
442 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
443 
444 	return(ifm->ifm_msglen);
445 }
446 
447 /*
448  * alloc buffer and get if_msghdrs block from kernel,
449  * and put them into the buffer
450  */
451 static void
452 get_iflist(char **buf, size_t *size)
453 {
454 	int mib[6];
455 
456 	mib[0] = CTL_NET;
457 	mib[1] = PF_ROUTE;
458 	mib[2] = 0;
459 	mib[3] = AF_INET6;
460 	mib[4] = NET_RT_IFLIST;
461 	mib[5] = 0;
462 
463 	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
464 		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
465 		       __FUNCTION__);
466 		exit(1);
467 	}
468 	if ((*buf = malloc(*size)) == NULL) {
469 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
470 		exit(1);
471 	}
472 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
473 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
474 		       __FUNCTION__);
475 		exit(1);
476 	}
477 	return;
478 }
479 
480 /*
481  * alloc buffer and parse if_msghdrs block passed as arg,
482  * and init the buffer as list of pointers ot each of the if_msghdr.
483  */
484 static void
485 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
486 {
487 	int iflentry_size, malloc_size;
488 	struct if_msghdr *ifm;
489 	struct ifa_msghdr *ifam;
490 	char *lim;
491 
492 	/*
493 	 * Estimate least size of an iflist entry, to be obtained from kernel.
494 	 * Should add sizeof(sockaddr) ??
495 	 */
496 	iflentry_size = sizeof(struct if_msghdr);
497 	/* roughly estimate max list size of pointers to each if_msghdr */
498 	malloc_size = (bufsize/iflentry_size) * sizeof(size_t);
499 	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
500 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
501 		exit(1);
502 	}
503 
504 	lim = buf + bufsize;
505 	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
506 		if (ifm->ifm_msglen == 0) {
507 			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
508 			       "(buf=%p lim=%p ifm=%p)", __FUNCTION__,
509 			       buf, lim, ifm);
510 			return;
511 		}
512 
513 		if (ifm->ifm_type == RTM_IFINFO) {
514 			(*ifmlist_p)[ifm->ifm_index] = ifm;
515 		} else {
516 			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
517 			       "expected %d, got %d\n msglen = %d\n"
518 			       "buf:%p, ifm:%p, lim:%p\n",
519 			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
520 			       buf, ifm, lim);
521 			exit (1);
522 		}
523 		for (ifam = (struct ifa_msghdr *)
524 			((char *)ifm + ifm->ifm_msglen);
525 		     ifam < (struct ifa_msghdr *)lim;
526 		     ifam = (struct ifa_msghdr *)
527 		     	((char *)ifam + ifam->ifam_msglen)) {
528 			/* just for safety */
529 			if (!ifam->ifam_msglen) {
530 				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
531 				       "(buf=%p lim=%p ifam=%p)", __FUNCTION__,
532 				       buf, lim, ifam);
533 				return;
534 			}
535 			if (ifam->ifam_type != RTM_NEWADDR)
536 				break;
537 		}
538 		ifm = (struct if_msghdr *)ifam;
539 	}
540 }
541 
542 void
543 init_iflist()
544 {
545 	if (ifblock) {
546 		free(ifblock);
547 		ifblock_size = 0;
548 	}
549 	if (iflist)
550 		free(iflist);
551 	/* get iflist block from kernel */
552 	get_iflist(&ifblock, &ifblock_size);
553 
554 	/* make list of pointers to each if_msghdr */
555 	parse_iflist(&iflist, ifblock, ifblock_size);
556 
557 }
558