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if.c revision 1.17 
      1 /*	$NetBSD: if.c,v 1.17 2003/09/23 18:15:50 itojun Exp $	*/
      2 /*	$KAME: if.c,v 1.31 2003/09/23 10:58:20 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 
     33 #include <sys/param.h>
     34 #include <sys/socket.h>
     35 #include <sys/sysctl.h>
     36 #include <sys/ioctl.h>
     37 #include <net/if.h>
     38 #include <net/if_types.h>
     39 #include <ifaddrs.h>
     40 #include <net/if_ether.h>
     41 #include <net/route.h>
     42 #include <net/if_dl.h>
     43 #include <netinet/in.h>
     44 #include <netinet/icmp6.h>
     45 #include <unistd.h>
     46 #include <errno.h>
     47 #include <stdlib.h>
     48 #include <string.h>
     49 #include <syslog.h>
     50 #include "rtadvd.h"
     51 #include "if.h"
     52 
     53 #define ROUNDUP(a, size) \
     54 	(((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
     55 
     56 #define NEXT_SA(ap) (ap) = (struct sockaddr *) \
     57 	((caddr_t)(ap) + ((ap)->sa_len ? ROUNDUP((ap)->sa_len,\
     58 						 sizeof(u_long)) :\
     59 			  			 sizeof(u_long)))
     60 
     61 struct if_msghdr **iflist;
     62 int iflist_init_ok;
     63 size_t ifblock_size;
     64 char *ifblock;
     65 
     66 static void get_iflist __P((char **buf, size_t *size));
     67 static void parse_iflist __P((struct if_msghdr ***ifmlist_p, char *buf,
     68 		       size_t bufsize));
     69 
     70 static void
     71 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
     72 {
     73 	int i;
     74 
     75 	for (i = 0; i < RTAX_MAX; i++) {
     76 		if (addrs & (1 << i)) {
     77 			rti_info[i] = sa;
     78 			NEXT_SA(sa);
     79 		}
     80 		else
     81 			rti_info[i] = NULL;
     82 	}
     83 }
     84 
     85 struct sockaddr_dl *
     86 if_nametosdl(char *name)
     87 {
     88 	struct ifaddrs *ifap, *ifa;
     89 	struct sockaddr_dl *sdl;
     90 
     91 	if (getifaddrs(&ifap) != 0)
     92 		return (NULL);
     93 
     94 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
     95 		if (strcmp(ifa->ifa_name, name) != 0)
     96 			continue;
     97 		if (ifa->ifa_addr->sa_family != AF_LINK)
     98 			continue;
     99 
    100 		sdl = malloc(ifa->ifa_addr->sa_len);
    101 		if (!sdl)
    102 			continue;	/*XXX*/
    103 
    104 		memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
    105 		freeifaddrs(ifap);
    106 		return (sdl);
    107 	}
    108 
    109 	freeifaddrs(ifap);
    110 	return (NULL);
    111 }
    112 
    113 int
    114 if_getmtu(char *name)
    115 {
    116 	struct ifaddrs *ifap, *ifa;
    117 	struct if_data *ifd;
    118 	u_long mtu = 0;
    119 
    120 	if (getifaddrs(&ifap) < 0)
    121 		return(0);
    122 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
    123 		if (strcmp(ifa->ifa_name, name) == 0) {
    124 			ifd = ifa->ifa_data;
    125 			if (ifd)
    126 				mtu = ifd->ifi_mtu;
    127 			break;
    128 		}
    129 	}
    130 	freeifaddrs(ifap);
    131 
    132 #ifdef SIOCGIFMTU		/* XXX: this ifdef may not be necessary */
    133 	if (mtu == 0) {
    134 		struct ifreq ifr;
    135 		int s;
    136 
    137 		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    138 			return(0);
    139 
    140 		ifr.ifr_addr.sa_family = AF_INET6;
    141 		strncpy(ifr.ifr_name, name,
    142 			sizeof(ifr.ifr_name));
    143 		if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
    144 			close(s);
    145 			return(0);
    146 		}
    147 		close(s);
    148 
    149 		mtu = ifr.ifr_mtu;
    150 	}
    151 #endif
    152 
    153 	return(mtu);
    154 }
    155 
    156 /* give interface index and its old flags, then new flags returned */
    157 int
    158 if_getflags(int ifindex, int oifflags)
    159 {
    160 	struct ifreq ifr;
    161 	int s;
    162 
    163 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    164 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
    165 		       strerror(errno));
    166 		return (oifflags & ~IFF_UP);
    167 	}
    168 
    169 	if_indextoname(ifindex, ifr.ifr_name);
    170 	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
    171 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    172 		       __func__, ifr.ifr_name);
    173 		close(s);
    174 		return (oifflags & ~IFF_UP);
    175 	}
    176 	close(s);
    177 	return (ifr.ifr_flags);
    178 }
    179 
    180 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    181 int
    182 lladdropt_length(struct sockaddr_dl *sdl)
    183 {
    184 	switch (sdl->sdl_type) {
    185 	case IFT_ETHER:
    186 	case IFT_FDDI:
    187 		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    188 	default:
    189 		return(0);
    190 	}
    191 }
    192 
    193 void
    194 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    195 {
    196 	char *addr;
    197 
    198 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    199 
    200 	switch (sdl->sdl_type) {
    201 	case IFT_ETHER:
    202 	case IFT_FDDI:
    203 		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    204 		addr = (char *)(ndopt + 1);
    205 		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    206 		break;
    207 	default:
    208 		syslog(LOG_ERR, "<%s> unsupported link type(%d)",
    209 		    __func__, sdl->sdl_type);
    210 		exit(1);
    211 	}
    212 
    213 	return;
    214 }
    215 
    216 int
    217 rtbuf_len()
    218 {
    219 	size_t len;
    220 
    221 	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
    222 
    223 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
    224 		return(-1);
    225 
    226 	return(len);
    227 }
    228 
    229 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    230 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    231 #define SDL(s) ((struct sockaddr_dl *)(s))
    232 char *
    233 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    234 {
    235 	struct rt_msghdr *rtm;
    236 	struct ifa_msghdr *ifam;
    237 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    238 
    239 	*lenp = 0;
    240 	for (rtm = (struct rt_msghdr *)buf;
    241 	     rtm < (struct rt_msghdr *)lim;
    242 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    243 		/* just for safety */
    244 		if (!rtm->rtm_msglen) {
    245 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    246 				"(buf=%p lim=%p rtm=%p)", __func__,
    247 				buf, lim, rtm);
    248 			break;
    249 		}
    250 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    251 			continue;
    252 		}
    253 
    254 		switch (rtm->rtm_type) {
    255 		case RTM_GET:
    256 		case RTM_ADD:
    257 		case RTM_DELETE:
    258 			/* address related checks */
    259 			sa = (struct sockaddr *)(rtm + 1);
    260 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    261 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    262 			    dst->sa_family != AF_INET6)
    263 				continue;
    264 
    265 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    266 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    267 				continue;
    268 
    269 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    270 			    gw->sa_family != AF_LINK)
    271 				continue;
    272 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    273 				continue;
    274 
    275 			if (rti_info[RTAX_NETMASK] == NULL)
    276 				continue;
    277 
    278 			/* found */
    279 			*lenp = rtm->rtm_msglen;
    280 			return (char *)rtm;
    281 			/* NOTREACHED */
    282 		case RTM_NEWADDR:
    283 		case RTM_DELADDR:
    284 			ifam = (struct ifa_msghdr *)rtm;
    285 
    286 			/* address related checks */
    287 			sa = (struct sockaddr *)(ifam + 1);
    288 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    289 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    290 			    (ifa->sa_family != AF_INET &&
    291 			     ifa->sa_family != AF_INET6))
    292 				continue;
    293 
    294 			if (ifa->sa_family == AF_INET6 &&
    295 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    296 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    297 				continue;
    298 
    299 			if (ifindex && ifam->ifam_index != ifindex)
    300 				continue;
    301 
    302 			/* found */
    303 			*lenp = ifam->ifam_msglen;
    304 			return (char *)rtm;
    305 			/* NOTREACHED */
    306 		case RTM_IFINFO:
    307 			/* found */
    308 			*lenp = rtm->rtm_msglen;
    309 			return (char *)rtm;
    310 			/* NOTREACHED */
    311 		}
    312 	}
    313 
    314 	return (char *)rtm;
    315 }
    316 #undef FILTER_MATCH
    317 
    318 struct in6_addr *
    319 get_addr(char *buf)
    320 {
    321 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    322 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    323 
    324 	sa = (struct sockaddr *)(rtm + 1);
    325 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    326 
    327 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    328 }
    329 
    330 int
    331 get_rtm_ifindex(char *buf)
    332 {
    333 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    334 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    335 
    336 	sa = (struct sockaddr *)(rtm + 1);
    337 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    338 
    339 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    340 }
    341 
    342 int
    343 get_ifm_ifindex(char *buf)
    344 {
    345 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    346 
    347 	return ((int)ifm->ifm_index);
    348 }
    349 
    350 int
    351 get_ifam_ifindex(char *buf)
    352 {
    353 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    354 
    355 	return ((int)ifam->ifam_index);
    356 }
    357 
    358 int
    359 get_ifm_flags(char *buf)
    360 {
    361 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    362 
    363 	return (ifm->ifm_flags);
    364 }
    365 
    366 int
    367 get_prefixlen(char *buf)
    368 {
    369 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    370 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    371 	u_char *p, *lim;
    372 
    373 	sa = (struct sockaddr *)(rtm + 1);
    374 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    375 	sa = rti_info[RTAX_NETMASK];
    376 
    377 	p = (u_char *)(&SIN6(sa)->sin6_addr);
    378 	lim = (u_char *)sa + sa->sa_len;
    379 	return prefixlen(p, lim);
    380 }
    381 
    382 int
    383 prefixlen(u_char *p, u_char *lim)
    384 {
    385 	int masklen;
    386 
    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 		       __func__);
    466 		exit(1);
    467 	}
    468 	if ((*buf = malloc(*size)) == NULL) {
    469 		syslog(LOG_ERR, "<%s> malloc failed", __func__);
    470 		exit(1);
    471 	}
    472 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
    473 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
    474 		       __func__);
    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", __func__);
    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)", __func__,
    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)", __func__,
    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