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if.c revision 1.15 
      1 /*	$NetBSD: if.c,v 1.15 2003/09/20 13:04:07 itojun Exp $	*/
      2 /*	$KAME: if.c,v 1.21 2002/05/21 14:26:55 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 	int mib[6] = {CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
     89 	char *buf, *next, *lim;
     90 	size_t len;
     91 	struct if_msghdr *ifm;
     92 	struct sockaddr *sa, *rti_info[RTAX_MAX];
     93 	struct sockaddr_dl *sdl = NULL, *ret_sdl = NULL;
     94 
     95 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
     96 		return (NULL);
     97 	if ((buf = malloc(len)) == NULL)
     98 		return (NULL);
     99 	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0)
    100 		goto end;
    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 (strlen(name) != sdl->sdl_nlen)
    112 						continue; /* not same len */
    113 					if (strncmp(&sdl->sdl_data[0],
    114 						    name,
    115 						    sdl->sdl_nlen) == 0) {
    116 						break;
    117 					}
    118 				}
    119 			}
    120 		}
    121 	}
    122 	if (next == lim) {
    123 		/* search failed */
    124 		goto end;
    125 	}
    126 
    127 	if ((ret_sdl = malloc(sdl->sdl_len)) == NULL)
    128 		goto end;
    129 	memcpy((caddr_t)ret_sdl, (caddr_t)sdl, sdl->sdl_len);
    130 	return (ret_sdl);
    131 
    132   end:
    133 	free(buf);
    134 	return (ret_sdl);
    135 }
    136 
    137 int
    138 if_getmtu(char *name)
    139 {
    140 	struct ifaddrs *ifap, *ifa;
    141 	struct if_data *ifd;
    142 	u_long mtu = 0;
    143 
    144 	if (getifaddrs(&ifap) < 0)
    145 		return(0);
    146 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
    147 		if (strcmp(ifa->ifa_name, name) == 0) {
    148 			ifd = ifa->ifa_data;
    149 			if (ifd)
    150 				mtu = ifd->ifi_mtu;
    151 			break;
    152 		}
    153 	}
    154 	freeifaddrs(ifap);
    155 
    156 #ifdef SIOCGIFMTU		/* XXX: this ifdef may not be necessary */
    157 	if (mtu == 0) {
    158 		struct ifreq ifr;
    159 		int s;
    160 
    161 		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    162 			return(0);
    163 
    164 		ifr.ifr_addr.sa_family = AF_INET6;
    165 		strncpy(ifr.ifr_name, name,
    166 			sizeof(ifr.ifr_name));
    167 		if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
    168 			close(s);
    169 			return(0);
    170 		}
    171 		close(s);
    172 
    173 		mtu = ifr.ifr_mtu;
    174 	}
    175 #endif
    176 
    177 	return(mtu);
    178 }
    179 
    180 /* give interface index and its old flags, then new flags returned */
    181 int
    182 if_getflags(int ifindex, int oifflags)
    183 {
    184 	struct ifreq ifr;
    185 	int s;
    186 
    187 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    188 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
    189 		       strerror(errno));
    190 		return (oifflags & ~IFF_UP);
    191 	}
    192 
    193 	if_indextoname(ifindex, ifr.ifr_name);
    194 	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
    195 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    196 		       __func__, ifr.ifr_name);
    197 		close(s);
    198 		return (oifflags & ~IFF_UP);
    199 	}
    200 	close(s);
    201 	return (ifr.ifr_flags);
    202 }
    203 
    204 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    205 int
    206 lladdropt_length(struct sockaddr_dl *sdl)
    207 {
    208 	switch (sdl->sdl_type) {
    209 	case IFT_ETHER:
    210 	case IFT_FDDI:
    211 		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    212 	default:
    213 		return(0);
    214 	}
    215 }
    216 
    217 void
    218 lladdropt_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 	case IFT_FDDI:
    227 		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    228 		addr = (char *)(ndopt + 1);
    229 		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    230 		break;
    231 	default:
    232 		syslog(LOG_ERR, "<%s> unsupported link type(%d)",
    233 		    __func__, sdl->sdl_type);
    234 		exit(1);
    235 	}
    236 
    237 	return;
    238 }
    239 
    240 int
    241 rtbuf_len()
    242 {
    243 	size_t len;
    244 
    245 	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
    246 
    247 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
    248 		return(-1);
    249 
    250 	return(len);
    251 }
    252 
    253 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    254 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    255 #define SDL(s) ((struct sockaddr_dl *)(s))
    256 char *
    257 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    258 {
    259 	struct rt_msghdr *rtm;
    260 	struct ifa_msghdr *ifam;
    261 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    262 
    263 	*lenp = 0;
    264 	for (rtm = (struct rt_msghdr *)buf;
    265 	     rtm < (struct rt_msghdr *)lim;
    266 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    267 		/* just for safety */
    268 		if (!rtm->rtm_msglen) {
    269 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    270 				"(buf=%p lim=%p rtm=%p)", __func__,
    271 				buf, lim, rtm);
    272 			break;
    273 		}
    274 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    275 			continue;
    276 		}
    277 
    278 		switch (rtm->rtm_type) {
    279 		case RTM_GET:
    280 		case RTM_ADD:
    281 		case RTM_DELETE:
    282 			/* address related checks */
    283 			sa = (struct sockaddr *)(rtm + 1);
    284 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    285 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    286 			    dst->sa_family != AF_INET6)
    287 				continue;
    288 
    289 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    290 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    291 				continue;
    292 
    293 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    294 			    gw->sa_family != AF_LINK)
    295 				continue;
    296 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    297 				continue;
    298 
    299 			if (rti_info[RTAX_NETMASK] == NULL)
    300 				continue;
    301 
    302 			/* found */
    303 			*lenp = rtm->rtm_msglen;
    304 			return (char *)rtm;
    305 			/* NOTREACHED */
    306 		case RTM_NEWADDR:
    307 		case RTM_DELADDR:
    308 			ifam = (struct ifa_msghdr *)rtm;
    309 
    310 			/* address related checks */
    311 			sa = (struct sockaddr *)(ifam + 1);
    312 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    313 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    314 			    (ifa->sa_family != AF_INET &&
    315 			     ifa->sa_family != AF_INET6))
    316 				continue;
    317 
    318 			if (ifa->sa_family == AF_INET6 &&
    319 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    320 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    321 				continue;
    322 
    323 			if (ifindex && ifam->ifam_index != ifindex)
    324 				continue;
    325 
    326 			/* found */
    327 			*lenp = ifam->ifam_msglen;
    328 			return (char *)rtm;
    329 			/* NOTREACHED */
    330 		case RTM_IFINFO:
    331 			/* found */
    332 			*lenp = rtm->rtm_msglen;
    333 			return (char *)rtm;
    334 			/* NOTREACHED */
    335 		}
    336 	}
    337 
    338 	return (char *)rtm;
    339 }
    340 #undef FILTER_MATCH
    341 
    342 struct in6_addr *
    343 get_addr(char *buf)
    344 {
    345 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    346 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    347 
    348 	sa = (struct sockaddr *)(rtm + 1);
    349 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    350 
    351 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    352 }
    353 
    354 int
    355 get_rtm_ifindex(char *buf)
    356 {
    357 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    358 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    359 
    360 	sa = (struct sockaddr *)(rtm + 1);
    361 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    362 
    363 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    364 }
    365 
    366 int
    367 get_ifm_ifindex(char *buf)
    368 {
    369 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    370 
    371 	return ((int)ifm->ifm_index);
    372 }
    373 
    374 int
    375 get_ifam_ifindex(char *buf)
    376 {
    377 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    378 
    379 	return ((int)ifam->ifam_index);
    380 }
    381 
    382 int
    383 get_ifm_flags(char *buf)
    384 {
    385 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    386 
    387 	return (ifm->ifm_flags);
    388 }
    389 
    390 int
    391 get_prefixlen(char *buf)
    392 {
    393 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    394 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    395 	u_char *p, *lim;
    396 
    397 	sa = (struct sockaddr *)(rtm + 1);
    398 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    399 	sa = rti_info[RTAX_NETMASK];
    400 
    401 	p = (u_char *)(&SIN6(sa)->sin6_addr);
    402 	lim = (u_char *)sa + sa->sa_len;
    403 	return prefixlen(p, lim);
    404 }
    405 
    406 int
    407 prefixlen(u_char *p, u_char *lim)
    408 {
    409 	int masklen;
    410 
    411 	for (masklen = 0; p < lim; p++) {
    412 		switch (*p) {
    413 		case 0xff:
    414 			masklen += 8;
    415 			break;
    416 		case 0xfe:
    417 			masklen += 7;
    418 			break;
    419 		case 0xfc:
    420 			masklen += 6;
    421 			break;
    422 		case 0xf8:
    423 			masklen += 5;
    424 			break;
    425 		case 0xf0:
    426 			masklen += 4;
    427 			break;
    428 		case 0xe0:
    429 			masklen += 3;
    430 			break;
    431 		case 0xc0:
    432 			masklen += 2;
    433 			break;
    434 		case 0x80:
    435 			masklen += 1;
    436 			break;
    437 		case 0x00:
    438 			break;
    439 		default:
    440 			return(-1);
    441 		}
    442 	}
    443 
    444 	return(masklen);
    445 }
    446 
    447 int
    448 rtmsg_type(char *buf)
    449 {
    450 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    451 
    452 	return(rtm->rtm_type);
    453 }
    454 
    455 int
    456 rtmsg_len(char *buf)
    457 {
    458 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    459 
    460 	return(rtm->rtm_msglen);
    461 }
    462 
    463 int
    464 ifmsg_len(char *buf)
    465 {
    466 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    467 
    468 	return(ifm->ifm_msglen);
    469 }
    470 
    471 /*
    472  * alloc buffer and get if_msghdrs block from kernel,
    473  * and put them into the buffer
    474  */
    475 static void
    476 get_iflist(char **buf, size_t *size)
    477 {
    478 	int mib[6];
    479 
    480 	mib[0] = CTL_NET;
    481 	mib[1] = PF_ROUTE;
    482 	mib[2] = 0;
    483 	mib[3] = AF_INET6;
    484 	mib[4] = NET_RT_IFLIST;
    485 	mib[5] = 0;
    486 
    487 	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
    488 		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
    489 		       __func__);
    490 		exit(1);
    491 	}
    492 	if ((*buf = malloc(*size)) == NULL) {
    493 		syslog(LOG_ERR, "<%s> malloc failed", __func__);
    494 		exit(1);
    495 	}
    496 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
    497 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
    498 		       __func__);
    499 		exit(1);
    500 	}
    501 	return;
    502 }
    503 
    504 /*
    505  * alloc buffer and parse if_msghdrs block passed as arg,
    506  * and init the buffer as list of pointers ot each of the if_msghdr.
    507  */
    508 static void
    509 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
    510 {
    511 	int iflentry_size, malloc_size;
    512 	struct if_msghdr *ifm;
    513 	struct ifa_msghdr *ifam;
    514 	char *lim;
    515 
    516 	/*
    517 	 * Estimate least size of an iflist entry, to be obtained from kernel.
    518 	 * Should add sizeof(sockaddr) ??
    519 	 */
    520 	iflentry_size = sizeof(struct if_msghdr);
    521 	/* roughly estimate max list size of pointers to each if_msghdr */
    522 	malloc_size = (bufsize/iflentry_size) * sizeof(size_t);
    523 	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
    524 		syslog(LOG_ERR, "<%s> malloc failed", __func__);
    525 		exit(1);
    526 	}
    527 
    528 	lim = buf + bufsize;
    529 	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
    530 		if (ifm->ifm_msglen == 0) {
    531 			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
    532 			       "(buf=%p lim=%p ifm=%p)", __func__,
    533 			       buf, lim, ifm);
    534 			return;
    535 		}
    536 
    537 		if (ifm->ifm_type == RTM_IFINFO) {
    538 			(*ifmlist_p)[ifm->ifm_index] = ifm;
    539 		} else {
    540 			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
    541 			       "expected %d, got %d\n msglen = %d\n"
    542 			       "buf:%p, ifm:%p, lim:%p\n",
    543 			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
    544 			       buf, ifm, lim);
    545 			exit (1);
    546 		}
    547 		for (ifam = (struct ifa_msghdr *)
    548 			((char *)ifm + ifm->ifm_msglen);
    549 		     ifam < (struct ifa_msghdr *)lim;
    550 		     ifam = (struct ifa_msghdr *)
    551 		     	((char *)ifam + ifam->ifam_msglen)) {
    552 			/* just for safety */
    553 			if (!ifam->ifam_msglen) {
    554 				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
    555 				       "(buf=%p lim=%p ifam=%p)", __func__,
    556 				       buf, lim, ifam);
    557 				return;
    558 			}
    559 			if (ifam->ifam_type != RTM_NEWADDR)
    560 				break;
    561 		}
    562 		ifm = (struct if_msghdr *)ifam;
    563 	}
    564 }
    565 
    566 void
    567 init_iflist()
    568 {
    569 	if (ifblock) {
    570 		free(ifblock);
    571 		ifblock_size = 0;
    572 	}
    573 	if (iflist)
    574 		free(iflist);
    575 	/* get iflist block from kernel */
    576 	get_iflist(&ifblock, &ifblock_size);
    577 
    578 	/* make list of pointers to each if_msghdr */
    579 	parse_iflist(&iflist, ifblock, ifblock_size);
    580 }
    581