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if.c revision 1.18.42.1 
      1 /*	$NetBSD: if.c,v 1.18.42.1 2012/04/17 00:09:53 yamt Exp $	*/
      2 /*	$KAME: if.c,v 1.36 2004/11/30 22:32:01 suz 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 #ifndef RT_ROUNDUP
     54 #define RT_ROUNDUP(a)							       \
     55 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
     56 #define RT_ADVANCE(x, n) (x += RT_ROUNDUP((n)->sa_len))
     57 #endif
     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(char **buf, size_t *size);
     65 static void parse_iflist(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 			RT_ADVANCE(sa, sa);
     77 		}
     78 		else
     79 			rti_info[i] = NULL;
     80 	}
     81 }
     82 
     83 struct sockaddr_dl *
     84 if_nametosdl(const char *name)
     85 {
     86 	struct ifaddrs *ifap, *ifa;
     87 	struct sockaddr_dl *sdl;
     88 
     89 	if (getifaddrs(&ifap) != 0)
     90 		return (NULL);
     91 
     92 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
     93 		if (strcmp(ifa->ifa_name, name) != 0)
     94 			continue;
     95 		if (ifa->ifa_addr->sa_family != AF_LINK)
     96 			continue;
     97 
     98 		sdl = malloc(ifa->ifa_addr->sa_len);
     99 		if (!sdl)
    100 			continue;	/*XXX*/
    101 
    102 		memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
    103 		freeifaddrs(ifap);
    104 		return (sdl);
    105 	}
    106 
    107 	freeifaddrs(ifap);
    108 	return (NULL);
    109 }
    110 
    111 int
    112 if_getmtu(const char *name)
    113 {
    114 	struct ifaddrs *ifap, *ifa;
    115 	struct if_data *ifd;
    116 	u_long mtu = 0;
    117 
    118 	if (getifaddrs(&ifap) < 0)
    119 		return(0);
    120 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
    121 		if (strcmp(ifa->ifa_name, name) == 0) {
    122 			ifd = ifa->ifa_data;
    123 			if (ifd)
    124 				mtu = ifd->ifi_mtu;
    125 			break;
    126 		}
    127 	}
    128 	freeifaddrs(ifap);
    129 
    130 #ifdef SIOCGIFMTU		/* XXX: this ifdef may not be necessary */
    131 	if (mtu == 0) {
    132 		struct ifreq ifr;
    133 		int s;
    134 
    135 		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    136 			return(0);
    137 
    138 		ifr.ifr_addr.sa_family = AF_INET6;
    139 		strncpy(ifr.ifr_name, name,
    140 			sizeof(ifr.ifr_name));
    141 		if (ioctl(s, SIOCGIFMTU, &ifr) < 0) {
    142 			close(s);
    143 			return(0);
    144 		}
    145 		close(s);
    146 
    147 		mtu = ifr.ifr_mtu;
    148 	}
    149 #endif
    150 
    151 	return(mtu);
    152 }
    153 
    154 /* give interface index and its old flags, then new flags returned */
    155 int
    156 if_getflags(int ifindex, int oifflags)
    157 {
    158 	struct ifreq ifr;
    159 	int s;
    160 
    161 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    162 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
    163 		       strerror(errno));
    164 		return (oifflags & ~IFF_UP);
    165 	}
    166 
    167 	if_indextoname(ifindex, ifr.ifr_name);
    168 	if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
    169 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    170 		       __func__, ifr.ifr_name);
    171 		close(s);
    172 		return (oifflags & ~IFF_UP);
    173 	}
    174 	close(s);
    175 	return (ifr.ifr_flags);
    176 }
    177 
    178 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    179 int
    180 lladdropt_length(struct sockaddr_dl *sdl)
    181 {
    182 	switch (sdl->sdl_type) {
    183 	case IFT_ETHER:
    184 	case IFT_FDDI:
    185 		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    186 	default:
    187 		return(0);
    188 	}
    189 }
    190 
    191 void
    192 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    193 {
    194 	char *addr;
    195 
    196 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    197 
    198 	switch (sdl->sdl_type) {
    199 	case IFT_ETHER:
    200 	case IFT_FDDI:
    201 		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    202 		addr = (char *)(ndopt + 1);
    203 		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    204 		break;
    205 	default:
    206 		syslog(LOG_ERR, "<%s> unsupported link type(%d)",
    207 		    __func__, sdl->sdl_type);
    208 		exit(1);
    209 	}
    210 
    211 	return;
    212 }
    213 
    214 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    215 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    216 #define SDL(s) ((struct sockaddr_dl *)(s))
    217 char *
    218 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    219 {
    220 	struct rt_msghdr *rtm;
    221 	struct ifa_msghdr *ifam;
    222 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    223 
    224 	*lenp = 0;
    225 	for (rtm = (struct rt_msghdr *)buf;
    226 	     rtm < (struct rt_msghdr *)lim;
    227 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    228 		/* just for safety */
    229 		if (!rtm->rtm_msglen) {
    230 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    231 				"(buf=%p lim=%p rtm=%p)", __func__,
    232 				buf, lim, rtm);
    233 			break;
    234 		}
    235 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    236 			continue;
    237 		}
    238 
    239 		switch (rtm->rtm_type) {
    240 		case RTM_GET:
    241 		case RTM_ADD:
    242 		case RTM_DELETE:
    243 			/* address related checks */
    244 			sa = (struct sockaddr *)(rtm + 1);
    245 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    246 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    247 			    dst->sa_family != AF_INET6)
    248 				continue;
    249 
    250 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    251 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    252 				continue;
    253 
    254 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    255 			    gw->sa_family != AF_LINK)
    256 				continue;
    257 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    258 				continue;
    259 
    260 			if (rti_info[RTAX_NETMASK] == NULL)
    261 				continue;
    262 
    263 			/* found */
    264 			*lenp = rtm->rtm_msglen;
    265 			return (char *)rtm;
    266 			/* NOTREACHED */
    267 		case RTM_NEWADDR:
    268 		case RTM_DELADDR:
    269 			ifam = (struct ifa_msghdr *)rtm;
    270 
    271 			/* address related checks */
    272 			sa = (struct sockaddr *)(ifam + 1);
    273 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    274 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    275 			    (ifa->sa_family != AF_INET &&
    276 			     ifa->sa_family != AF_INET6))
    277 				continue;
    278 
    279 			if (ifa->sa_family == AF_INET6 &&
    280 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    281 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    282 				continue;
    283 
    284 			if (ifindex && ifam->ifam_index != ifindex)
    285 				continue;
    286 
    287 			/* found */
    288 			*lenp = ifam->ifam_msglen;
    289 			return (char *)rtm;
    290 			/* NOTREACHED */
    291 		case RTM_IFINFO:
    292 			/* found */
    293 			*lenp = rtm->rtm_msglen;
    294 			return (char *)rtm;
    295 			/* NOTREACHED */
    296 		}
    297 	}
    298 
    299 	return (char *)rtm;
    300 }
    301 #undef FILTER_MATCH
    302 
    303 struct in6_addr *
    304 get_addr(char *buf)
    305 {
    306 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    307 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    308 
    309 	sa = (struct sockaddr *)(rtm + 1);
    310 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    311 
    312 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    313 }
    314 
    315 int
    316 get_rtm_ifindex(char *buf)
    317 {
    318 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    319 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    320 
    321 	sa = (struct sockaddr *)(rtm + 1);
    322 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    323 
    324 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    325 }
    326 
    327 int
    328 get_ifm_ifindex(char *buf)
    329 {
    330 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    331 
    332 	return ((int)ifm->ifm_index);
    333 }
    334 
    335 int
    336 get_ifam_ifindex(char *buf)
    337 {
    338 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    339 
    340 	return ((int)ifam->ifam_index);
    341 }
    342 
    343 int
    344 get_ifm_flags(char *buf)
    345 {
    346 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    347 
    348 	return (ifm->ifm_flags);
    349 }
    350 
    351 int
    352 get_prefixlen(char *buf)
    353 {
    354 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    355 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    356 	unsigned char *p, *lim;
    357 
    358 	sa = (struct sockaddr *)(rtm + 1);
    359 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    360 	sa = rti_info[RTAX_NETMASK];
    361 
    362 	p = (unsigned char *)(&SIN6(sa)->sin6_addr);
    363 	lim = (unsigned char *)sa + sa->sa_len;
    364 	return prefixlen(p, lim);
    365 }
    366 
    367 int
    368 prefixlen(const unsigned char *p, const unsigned char *lim)
    369 {
    370 	int masklen;
    371 
    372 	for (masklen = 0; p < lim; p++) {
    373 		switch (*p) {
    374 		case 0xff:
    375 			masklen += 8;
    376 			break;
    377 		case 0xfe:
    378 			masklen += 7;
    379 			break;
    380 		case 0xfc:
    381 			masklen += 6;
    382 			break;
    383 		case 0xf8:
    384 			masklen += 5;
    385 			break;
    386 		case 0xf0:
    387 			masklen += 4;
    388 			break;
    389 		case 0xe0:
    390 			masklen += 3;
    391 			break;
    392 		case 0xc0:
    393 			masklen += 2;
    394 			break;
    395 		case 0x80:
    396 			masklen += 1;
    397 			break;
    398 		case 0x00:
    399 			break;
    400 		default:
    401 			return(-1);
    402 		}
    403 	}
    404 
    405 	return(masklen);
    406 }
    407 
    408 int
    409 rtmsg_type(char *buf)
    410 {
    411 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    412 
    413 	return(rtm->rtm_type);
    414 }
    415 
    416 int
    417 rtmsg_len(char *buf)
    418 {
    419 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    420 
    421 	return(rtm->rtm_msglen);
    422 }
    423 
    424 int
    425 ifmsg_len(char *buf)
    426 {
    427 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    428 
    429 	return(ifm->ifm_msglen);
    430 }
    431 
    432 /*
    433  * alloc buffer and get if_msghdrs block from kernel,
    434  * and put them into the buffer
    435  */
    436 static void
    437 get_iflist(char **buf, size_t *size)
    438 {
    439 	int mib[6];
    440 
    441 	mib[0] = CTL_NET;
    442 	mib[1] = PF_ROUTE;
    443 	mib[2] = 0;
    444 	mib[3] = AF_INET6;
    445 	mib[4] = NET_RT_IFLIST;
    446 	mib[5] = 0;
    447 
    448 	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
    449 		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
    450 		       __func__);
    451 		exit(1);
    452 	}
    453 	if ((*buf = malloc(*size)) == NULL) {
    454 		syslog(LOG_ERR, "<%s> malloc failed", __func__);
    455 		exit(1);
    456 	}
    457 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
    458 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
    459 		       __func__);
    460 		exit(1);
    461 	}
    462 	return;
    463 }
    464 
    465 /*
    466  * alloc buffer and parse if_msghdrs block passed as arg,
    467  * and init the buffer as list of pointers ot each of the if_msghdr.
    468  */
    469 static void
    470 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
    471 {
    472 	int iflentry_size, malloc_size;
    473 	struct if_msghdr *ifm;
    474 	struct ifa_msghdr *ifam;
    475 	char *lim;
    476 
    477 	/*
    478 	 * Estimate least size of an iflist entry, to be obtained from kernel.
    479 	 * Should add sizeof(sockaddr) ??
    480 	 */
    481 	iflentry_size = sizeof(struct if_msghdr);
    482 	/* roughly estimate max list size of pointers to each if_msghdr */
    483 	malloc_size = (bufsize/iflentry_size) * sizeof(void *);
    484 	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
    485 		syslog(LOG_ERR, "<%s> malloc failed", __func__);
    486 		exit(1);
    487 	}
    488 
    489 	lim = buf + bufsize;
    490 	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
    491 		if (ifm->ifm_msglen == 0) {
    492 			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
    493 			       "(buf=%p lim=%p ifm=%p)", __func__,
    494 			       buf, lim, ifm);
    495 			return;
    496 		}
    497 
    498 		if (ifm->ifm_type == RTM_IFINFO) {
    499 			(*ifmlist_p)[ifm->ifm_index] = ifm;
    500 		} else {
    501 			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
    502 			       "expected %d, got %d\n msglen = %d\n"
    503 			       "buf:%p, ifm:%p, lim:%p\n",
    504 			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
    505 			       buf, ifm, lim);
    506 			exit (1);
    507 		}
    508 		for (ifam = (struct ifa_msghdr *)
    509 			((char *)ifm + ifm->ifm_msglen);
    510 		     ifam < (struct ifa_msghdr *)lim;
    511 		     ifam = (struct ifa_msghdr *)
    512 		     	((char *)ifam + ifam->ifam_msglen)) {
    513 			/* just for safety */
    514 			if (!ifam->ifam_msglen) {
    515 				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
    516 				       "(buf=%p lim=%p ifam=%p)", __func__,
    517 				       buf, lim, ifam);
    518 				return;
    519 			}
    520 			if (ifam->ifam_type != RTM_NEWADDR)
    521 				break;
    522 		}
    523 		ifm = (struct if_msghdr *)ifam;
    524 	}
    525 }
    526 
    527 void
    528 init_iflist()
    529 {
    530 	if (ifblock) {
    531 		free(ifblock);
    532 		ifblock_size = 0;
    533 	}
    534 	if (iflist)
    535 		free(iflist);
    536 	/* get iflist block from kernel */
    537 	get_iflist(&ifblock, &ifblock_size);
    538 
    539 	/* make list of pointers to each if_msghdr */
    540 	parse_iflist(&iflist, ifblock, ifblock_size);
    541 }
    542