1/*	$KAME: if.c,v 1.17 2001/01/21 15:27:30 itojun Exp $	*/
2
3/*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
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 <ifaddrs.h>
40#include <net/route.h>
41#include <net/if_dl.h>
42#include <netinet/in.h>
43#include <netinet/icmp6.h>
44#include <unistd.h>
45#include <errno.h>
46#include <stdlib.h>
47#include <string.h>
48#include <syslog.h>
49#include "rtadvd.h"
50#include "if.h"
51
52#define ROUNDUP(a, size) \
53	(((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
54
55#define NEXT_SA(ap) (ap) = (struct sockaddr *) \
56	((caddr_t)(ap) + ((ap)->sa_len ? ROUNDUP((ap)->sa_len,\
57						 sizeof(uint32_t)) :\
58			  			 sizeof(uint32_t)))
59
60struct if_msghdr **iflist;
61int iflist_init_ok;
62size_t ifblock_size;
63char *ifblock;
64
65static void get_iflist(char **buf, size_t *size);
66static void parse_iflist(struct if_msghdr ***ifmlist_p, char *buf,
67		       size_t bufsize);
68
69static void
70get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
71{
72	int i;
73
74	for (i = 0; i < RTAX_MAX; i++) {
75		if (addrs & (1 << i)) {
76			rti_info[i] = sa;
77			NEXT_SA(sa);
78		}
79		else
80			rti_info[i] = NULL;
81	}
82}
83
84struct sockaddr_dl *
85if_nametosdl(char *name)
86{
87	int mib[6] = {CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
88	char *buf, *next, *lim;
89	size_t len;
90	struct if_msghdr *ifm;
91	struct sockaddr *sa, *rti_info[RTAX_MAX];
92	struct sockaddr_dl *sdl = NULL, *ret_sdl;
93
94	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
95		return(NULL);
96	if ((buf = malloc(len)) == NULL)
97		return(NULL);
98	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
99		free(buf);
100		return(NULL);
101	}
102
103	lim = buf + len;
104	for (next = buf; next < lim; next += ifm->ifm_msglen) {
105		ifm = (struct if_msghdr *)next;
106		if (ifm->ifm_type == RTM_IFINFO) {
107			sa = (struct sockaddr *)(ifm + 1);
108			get_rtaddrs(ifm->ifm_addrs, sa, rti_info);
109			if ((sa = rti_info[RTAX_IFP]) != NULL) {
110				if (sa->sa_family == AF_LINK) {
111					sdl = (struct sockaddr_dl *)sa;
112					if (strlen(name) != sdl->sdl_nlen)
113						continue; /* not same len */
114					if (strncmp(&sdl->sdl_data[0],
115						    name,
116						    sdl->sdl_nlen) == 0) {
117						break;
118					}
119				}
120			}
121		}
122	}
123	if (next == lim) {
124		/* search failed */
125		free(buf);
126		return(NULL);
127	}
128
129	if ((ret_sdl = malloc(sdl->sdl_len)) == NULL)
130		goto end;
131	memcpy((caddr_t)ret_sdl, (caddr_t)sdl, sdl->sdl_len);
132
133end:
134	free(buf);
135	return(ret_sdl);
136}
137
138int
139if_getmtu(char *name)
140{
141	struct ifaddrs *ifap, *ifa;
142	struct if_data *ifd;
143	int mtu = 0;
144
145	if (getifaddrs(&ifap) < 0)
146		return(0);
147	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
148		if (strcmp(ifa->ifa_name, name) == 0) {
149			ifd = ifa->ifa_data;
150			if (ifd)
151				mtu = ifd->ifi_mtu;
152			break;
153		}
154	}
155	freeifaddrs(ifap);
156
157#ifdef SIOCGIFMTU		/* XXX: this ifdef may not be necessary */
158	if (mtu == 0) {
159		struct ifreq ifr;
160		int s;
161
162		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
163			return(0);
164
165		ifr.ifr_addr.sa_family = AF_INET6;
166		strncpy(ifr.ifr_name, name,
167			sizeof(ifr.ifr_name));
168		if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
169			close(s);
170			return(0);
171		}
172		close(s);
173
174		mtu = ifr.ifr_mtu;
175	}
176#endif
177
178	return(mtu);
179}
180
181/* give interface index and its old flags, then new flags returned */
182int
183if_getflags(int ifindex, int oifflags)
184{
185	struct ifreq ifr;
186	int s;
187
188	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
189		syslog(LOG_ERR, "<%s> socket: %s", __func__,
190		       strerror(errno));
191		return (oifflags & ~IFF_UP);
192	}
193
194	if_indextoname(ifindex, ifr.ifr_name);
195	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
196		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
197		       __func__, ifr.ifr_name);
198		close(s);
199		return (oifflags & ~IFF_UP);
200	}
201	close(s);
202	return (ifr.ifr_flags);
203}
204
205#define ROUNDUP8(a) (1 + (((a) - 1) | 7))
206int
207lladdropt_length(struct sockaddr_dl *sdl)
208{
209	switch (sdl->sdl_type) {
210	case IFT_ETHER:
211		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
212	default:
213		return(0);
214	}
215}
216
217void
218lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
219{
220	char *addr;
221
222	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
223
224	switch (sdl->sdl_type) {
225	case IFT_ETHER:
226		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
227		addr = (char *)(ndopt + 1);
228		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
229		break;
230	default:
231		syslog(LOG_ERR, "<%s> unsupported link type(%d)",
232		    __func__, sdl->sdl_type);
233		exit(1);
234	}
235
236	return;
237}
238
239int
240rtbuf_len()
241{
242	size_t len;
243
244	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
245
246	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
247		return(-1);
248
249	return(len);
250}
251
252#define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
253#define SIN6(s) ((struct sockaddr_in6 *)(s))
254#define SDL(s) ((struct sockaddr_dl *)(s))
255char *
256get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
257{
258	struct rt_msghdr *rtm;
259	struct ifa_msghdr *ifam;
260	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
261
262	*lenp = 0;
263	for (rtm = (struct rt_msghdr *)buf;
264	     rtm < (struct rt_msghdr *)lim;
265	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
266		/* just for safety */
267		if (!rtm->rtm_msglen) {
268			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
269				"(buf=%p lim=%p rtm=%p)", __func__,
270				buf, lim, rtm);
271			break;
272		}
273		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
274			continue;
275		}
276
277		switch (rtm->rtm_type) {
278		case RTM_GET:
279		case RTM_ADD:
280		case RTM_DELETE:
281			/* address related checks */
282			sa = (struct sockaddr *)(rtm + 1);
283			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
284			if ((dst = rti_info[RTAX_DST]) == NULL ||
285			    dst->sa_family != AF_INET6)
286				continue;
287
288			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
289			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
290				continue;
291
292			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
293			    gw->sa_family != AF_LINK)
294				continue;
295			if (ifindex && SDL(gw)->sdl_index != ifindex)
296				continue;
297
298			if (rti_info[RTAX_NETMASK] == NULL)
299				continue;
300
301			/* found */
302			*lenp = rtm->rtm_msglen;
303			return (char *)rtm;
304			/* NOTREACHED */
305		case RTM_NEWADDR:
306		case RTM_DELADDR:
307			ifam = (struct ifa_msghdr *)rtm;
308
309			/* address related checks */
310			sa = (struct sockaddr *)(ifam + 1);
311			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
312			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
313			    (ifa->sa_family != AF_INET &&
314			     ifa->sa_family != AF_INET6))
315				continue;
316
317			if (ifa->sa_family == AF_INET6 &&
318			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
319			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
320				continue;
321
322			if (ifindex && ifam->ifam_index != ifindex)
323				continue;
324
325			/* found */
326			*lenp = ifam->ifam_msglen;
327			return (char *)rtm;
328			/* NOTREACHED */
329		case RTM_IFINFO:
330			/* found */
331			*lenp = rtm->rtm_msglen;
332			return (char *)rtm;
333			/* NOTREACHED */
334		}
335	}
336
337	return (char *)rtm;
338}
339#undef FILTER_MATCH
340
341struct in6_addr *
342get_addr(char *buf)
343{
344	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
345	struct sockaddr *sa, *rti_info[RTAX_MAX];
346
347	sa = (struct sockaddr *)(rtm + 1);
348	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
349
350	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
351}
352
353int
354get_rtm_ifindex(char *buf)
355{
356	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
357	struct sockaddr *sa, *rti_info[RTAX_MAX];
358
359	sa = (struct sockaddr *)(rtm + 1);
360	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
361
362	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
363}
364
365int
366get_ifm_ifindex(char *buf)
367{
368	struct if_msghdr *ifm = (struct if_msghdr *)buf;
369
370	return ((int)ifm->ifm_index);
371}
372
373int
374get_ifam_ifindex(char *buf)
375{
376	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
377
378	return ((int)ifam->ifam_index);
379}
380
381int
382get_ifm_flags(char *buf)
383{
384	struct if_msghdr *ifm = (struct if_msghdr *)buf;
385
386	return (ifm->ifm_flags);
387}
388
389int
390get_prefixlen(char *buf)
391{
392	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
393	struct sockaddr *sa, *rti_info[RTAX_MAX];
394	u_char *p, *lim;
395
396	sa = (struct sockaddr *)(rtm + 1);
397	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
398	sa = rti_info[RTAX_NETMASK];
399
400	p = (u_char *)(&SIN6(sa)->sin6_addr);
401	lim = (u_char *)sa + sa->sa_len;
402	return prefixlen(p, lim);
403}
404
405int
406prefixlen(u_char *p, u_char *lim)
407{
408	int masklen;
409
410	for (masklen = 0; p < lim; p++) {
411		switch (*p) {
412		case 0xff:
413			masklen += 8;
414			break;
415		case 0xfe:
416			masklen += 7;
417			break;
418		case 0xfc:
419			masklen += 6;
420			break;
421		case 0xf8:
422			masklen += 5;
423			break;
424		case 0xf0:
425			masklen += 4;
426			break;
427		case 0xe0:
428			masklen += 3;
429			break;
430		case 0xc0:
431			masklen += 2;
432			break;
433		case 0x80:
434			masklen += 1;
435			break;
436		case 0x00:
437			break;
438		default:
439			return(-1);
440		}
441	}
442
443	return(masklen);
444}
445
446int
447rtmsg_type(char *buf)
448{
449	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
450
451	return(rtm->rtm_type);
452}
453
454int
455rtmsg_len(char *buf)
456{
457	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
458
459	return(rtm->rtm_msglen);
460}
461
462int
463ifmsg_len(char *buf)
464{
465	struct if_msghdr *ifm = (struct if_msghdr *)buf;
466
467	return(ifm->ifm_msglen);
468}
469
470/*
471 * alloc buffer and get if_msghdrs block from kernel,
472 * and put them into the buffer
473 */
474static void
475get_iflist(char **buf, size_t *size)
476{
477	int mib[6];
478
479	mib[0] = CTL_NET;
480	mib[1] = PF_ROUTE;
481	mib[2] = 0;
482	mib[3] = AF_INET6;
483	mib[4] = NET_RT_IFLIST;
484	mib[5] = 0;
485
486	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
487		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
488		       __func__);
489		exit(1);
490	}
491	if ((*buf = malloc(*size)) == NULL) {
492		syslog(LOG_ERR, "<%s> malloc failed", __func__);
493		exit(1);
494	}
495	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
496		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
497		       __func__);
498		exit(1);
499	}
500	return;
501}
502
503/*
504 * alloc buffer and parse if_msghdrs block passed as arg,
505 * and init the buffer as list of pointers ot each of the if_msghdr.
506 */
507static void
508parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
509{
510	int iflentry_size, malloc_size;
511	struct if_msghdr *ifm;
512	struct ifa_msghdr *ifam;
513	char *lim;
514
515	/*
516	 * Estimate least size of an iflist entry, to be obtained from kernel.
517	 * Should add sizeof(sockaddr) ??
518	 */
519	iflentry_size = sizeof(struct if_msghdr);
520	/* roughly estimate max list size of pointers to each if_msghdr */
521	malloc_size = (bufsize/iflentry_size) * sizeof(size_t);
522	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
523		syslog(LOG_ERR, "<%s> malloc failed", __func__);
524		exit(1);
525	}
526
527	lim = buf + bufsize;
528	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
529		if (ifm->ifm_msglen == 0) {
530			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
531			       "(buf=%p lim=%p ifm=%p)", __func__,
532			       buf, lim, ifm);
533			return;
534		}
535
536		if (ifm->ifm_type == RTM_IFINFO) {
537			(*ifmlist_p)[ifm->ifm_index] = ifm;
538		} else {
539			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
540			       "expected %d, got %d\n msglen = %d\n"
541			       "buf:%p, ifm:%p, lim:%p\n",
542			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
543			       buf, ifm, lim);
544			exit (1);
545		}
546		for (ifam = (struct ifa_msghdr *)
547			((char *)ifm + ifm->ifm_msglen);
548		     ifam < (struct ifa_msghdr *)lim;
549		     ifam = (struct ifa_msghdr *)
550		     	((char *)ifam + ifam->ifam_msglen)) {
551			/* just for safety */
552			if (!ifam->ifam_msglen) {
553				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
554				       "(buf=%p lim=%p ifam=%p)", __func__,
555				       buf, lim, ifam);
556				return;
557			}
558			if (ifam->ifam_type != RTM_NEWADDR)
559				break;
560		}
561		ifm = (struct if_msghdr *)ifam;
562	}
563}
564
565void
566init_iflist()
567{
568	if (ifblock) {
569		free(ifblock);
570		ifblock_size = 0;
571	}
572	if (iflist)
573		free(iflist);
574	/* get iflist block from kernel */
575	get_iflist(&ifblock, &ifblock_size);
576
577	/* make list of pointers to each if_msghdr */
578	parse_iflist(&iflist, ifblock, ifblock_size);
579}
580