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if.c revision 1.10 
      1 /*	$NetBSD: if.c,v 1.10 2001/01/21 15:39:33 itojun Exp $	*/
      2 /*	$KAME: if.c,v 1.17 2001/01/21 15:27:30 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 #ifdef __FreeBSD__
     40 # include <net/ethernet.h>
     41 #endif
     42 #include <ifaddrs.h>
     43 #ifdef __NetBSD__
     44 #include <net/if_ether.h>
     45 #endif
     46 #include <net/route.h>
     47 #include <net/if_dl.h>
     48 #include <netinet/in.h>
     49 #include <netinet/icmp6.h>
     50 #ifdef __bsdi__
     51 # include <netinet/if_ether.h>
     52 #endif
     53 #ifdef __OpenBSD__
     54 #include <netinet/if_ether.h>
     55 #endif
     56 #include <unistd.h>
     57 #include <errno.h>
     58 #include <stdlib.h>
     59 #include <string.h>
     60 #include <syslog.h>
     61 #include "rtadvd.h"
     62 #include "if.h"
     63 
     64 #define ROUNDUP(a, size) \
     65 	(((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
     66 
     67 #define NEXT_SA(ap) (ap) = (struct sockaddr *) \
     68 	((caddr_t)(ap) + ((ap)->sa_len ? ROUNDUP((ap)->sa_len,\
     69 						 sizeof(u_long)) :\
     70 			  			 sizeof(u_long)))
     71 
     72 struct if_msghdr **iflist;
     73 int iflist_init_ok;
     74 size_t ifblock_size;
     75 char *ifblock;
     76 
     77 static void get_iflist __P((char **buf, size_t *size));
     78 static void parse_iflist __P((struct if_msghdr ***ifmlist_p, char *buf,
     79 		       size_t bufsize));
     80 
     81 static void
     82 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
     83 {
     84 	int i;
     85 
     86 	for (i = 0; i < RTAX_MAX; i++) {
     87 		if (addrs & (1 << i)) {
     88 			rti_info[i] = sa;
     89 			NEXT_SA(sa);
     90 		}
     91 		else
     92 			rti_info[i] = NULL;
     93 	}
     94 }
     95 
     96 struct sockaddr_dl *
     97 if_nametosdl(char *name)
     98 {
     99 	int mib[6] = {CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
    100 	char *buf, *next, *lim;
    101 	size_t len;
    102 	struct if_msghdr *ifm;
    103 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    104 	struct sockaddr_dl *sdl = NULL, *ret_sdl;
    105 
    106 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
    107 		return(NULL);
    108 	if ((buf = malloc(len)) == NULL)
    109 		return(NULL);
    110 	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
    111 		free(buf);
    112 		return(NULL);
    113 	}
    114 
    115 	lim = buf + len;
    116 	for (next = buf; next < lim; next += ifm->ifm_msglen) {
    117 		ifm = (struct if_msghdr *)next;
    118 		if (ifm->ifm_type == RTM_IFINFO) {
    119 			sa = (struct sockaddr *)(ifm + 1);
    120 			get_rtaddrs(ifm->ifm_addrs, sa, rti_info);
    121 			if ((sa = rti_info[RTAX_IFP]) != NULL) {
    122 				if (sa->sa_family == AF_LINK) {
    123 					sdl = (struct sockaddr_dl *)sa;
    124 					if (strlen(name) != sdl->sdl_nlen)
    125 						continue; /* not same len */
    126 					if (strncmp(&sdl->sdl_data[0],
    127 						    name,
    128 						    sdl->sdl_nlen) == 0) {
    129 						break;
    130 					}
    131 				}
    132 			}
    133 		}
    134 	}
    135 	if (next == lim) {
    136 		/* search failed */
    137 		free(buf);
    138 		return(NULL);
    139 	}
    140 
    141 	if ((ret_sdl = malloc(sdl->sdl_len)) == NULL)
    142 		return(NULL);
    143 	memcpy((caddr_t)ret_sdl, (caddr_t)sdl, sdl->sdl_len);
    144 	return(ret_sdl);
    145 }
    146 
    147 int
    148 if_getmtu(char *name)
    149 {
    150 	struct ifaddrs *ifap, *ifa;
    151 	struct if_data *ifd;
    152 	u_long mtu = 0;
    153 
    154 	if (getifaddrs(&ifap) < 0)
    155 		return(0);
    156 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
    157 		if (strcmp(ifa->ifa_name, name) == 0) {
    158 			ifd = ifa->ifa_data;
    159 			if (ifd)
    160 				mtu = ifd->ifi_mtu;
    161 			break;
    162 		}
    163 	}
    164 	freeifaddrs(ifap);
    165 
    166 #ifdef SIOCGIFMTU		/* XXX: this ifdef may not be necessary */
    167 	if (mtu == 0) {
    168 		struct ifreq ifr;
    169 		int s;
    170 
    171 		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    172 			return(0);
    173 
    174 		ifr.ifr_addr.sa_family = AF_INET6;
    175 		strncpy(ifr.ifr_name, name,
    176 			sizeof(ifr.ifr_name));
    177 		if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
    178 			close(s);
    179 			return(0);
    180 		}
    181 		close(s);
    182 
    183 		mtu = ifr.ifr_mtu;
    184 	}
    185 #endif
    186 
    187 	return(mtu);
    188 }
    189 
    190 /* give interface index and its old flags, then new flags returned */
    191 int
    192 if_getflags(int ifindex, int oifflags)
    193 {
    194 	struct ifreq ifr;
    195 	int s;
    196 
    197 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    198 		syslog(LOG_ERR, "<%s> socket: %s", __FUNCTION__,
    199 		       strerror(errno));
    200 		return (oifflags & ~IFF_UP);
    201 	}
    202 
    203 	if_indextoname(ifindex, ifr.ifr_name);
    204 	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
    205 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    206 		       __FUNCTION__, ifr.ifr_name);
    207 		close(s);
    208 		return (oifflags & ~IFF_UP);
    209 	}
    210 	close(s);
    211 	return (ifr.ifr_flags);
    212 }
    213 
    214 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    215 int
    216 lladdropt_length(struct sockaddr_dl *sdl)
    217 {
    218 	switch(sdl->sdl_type) {
    219 	 case IFT_ETHER:
    220 		 return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    221 	 default:
    222 		 return(0);
    223 	}
    224 }
    225 
    226 void
    227 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    228 {
    229 	char *addr;
    230 
    231 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    232 
    233 	switch(sdl->sdl_type) {
    234 	 case IFT_ETHER:
    235 		 ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    236 		 addr = (char *)(ndopt + 1);
    237 		 memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    238 		 break;
    239 	 default:
    240 		 syslog(LOG_ERR,
    241 			"<%s> unsupported link type(%d)",
    242 			__FUNCTION__, sdl->sdl_type);
    243 		 exit(1);
    244 	}
    245 
    246 	return;
    247 }
    248 
    249 int
    250 rtbuf_len()
    251 {
    252 	size_t len;
    253 
    254 	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
    255 
    256 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
    257 		return(-1);
    258 
    259 	return(len);
    260 }
    261 
    262 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    263 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    264 #define SDL(s) ((struct sockaddr_dl *)(s))
    265 char *
    266 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    267 {
    268 	struct rt_msghdr *rtm;
    269 	struct ifa_msghdr *ifam;
    270 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    271 
    272 	*lenp = 0;
    273 	for (rtm = (struct rt_msghdr *)buf;
    274 	     rtm < (struct rt_msghdr *)lim;
    275 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    276 		/* just for safety */
    277 		if (!rtm->rtm_msglen) {
    278 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    279 				"(buf=%p lim=%p rtm=%p)", __FUNCTION__,
    280 				buf, lim, rtm);
    281 			break;
    282 		}
    283 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    284 			continue;
    285 		}
    286 
    287 		switch (rtm->rtm_type) {
    288 		case RTM_GET:
    289 		case RTM_ADD:
    290 		case RTM_DELETE:
    291 			/* address related checks */
    292 			sa = (struct sockaddr *)(rtm + 1);
    293 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    294 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    295 			    dst->sa_family != AF_INET6)
    296 				continue;
    297 
    298 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    299 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    300 				continue;
    301 
    302 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    303 			    gw->sa_family != AF_LINK)
    304 				continue;
    305 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    306 				continue;
    307 
    308 			if (rti_info[RTAX_NETMASK] == NULL)
    309 				continue;
    310 
    311 			/* found */
    312 			*lenp = rtm->rtm_msglen;
    313 			return (char *)rtm;
    314 			/* NOTREACHED */
    315 		case RTM_NEWADDR:
    316 		case RTM_DELADDR:
    317 			ifam = (struct ifa_msghdr *)rtm;
    318 
    319 			/* address related checks */
    320 			sa = (struct sockaddr *)(ifam + 1);
    321 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    322 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    323 			    (ifa->sa_family != AF_INET &&
    324 			     ifa->sa_family != AF_INET6))
    325 				continue;
    326 
    327 			if (ifa->sa_family == AF_INET6 &&
    328 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    329 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    330 				continue;
    331 
    332 			if (ifindex && ifam->ifam_index != ifindex)
    333 				continue;
    334 
    335 			/* found */
    336 			*lenp = ifam->ifam_msglen;
    337 			return (char *)rtm;
    338 			/* NOTREACHED */
    339 		case RTM_IFINFO:
    340 			/* found */
    341 			*lenp = rtm->rtm_msglen;
    342 			return (char *)rtm;
    343 			/* NOTREACHED */
    344 		}
    345 	}
    346 
    347 	return (char *)rtm;
    348 }
    349 #undef FILTER_MATCH
    350 
    351 struct in6_addr *
    352 get_addr(char *buf)
    353 {
    354 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    355 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    356 
    357 	sa = (struct sockaddr *)(rtm + 1);
    358 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    359 
    360 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    361 }
    362 
    363 int
    364 get_rtm_ifindex(char *buf)
    365 {
    366 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    367 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    368 
    369 	sa = (struct sockaddr *)(rtm + 1);
    370 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    371 
    372 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    373 }
    374 
    375 int
    376 get_ifm_ifindex(char *buf)
    377 {
    378 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    379 
    380 	return ((int)ifm->ifm_index);
    381 }
    382 
    383 int
    384 get_ifam_ifindex(char *buf)
    385 {
    386 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    387 
    388 	return ((int)ifam->ifam_index);
    389 }
    390 
    391 int
    392 get_ifm_flags(char *buf)
    393 {
    394 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    395 
    396 	return (ifm->ifm_flags);
    397 }
    398 
    399 int
    400 get_prefixlen(char *buf)
    401 {
    402 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    403 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    404 	u_char *p, *lim;
    405 
    406 	sa = (struct sockaddr *)(rtm + 1);
    407 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    408 	sa = rti_info[RTAX_NETMASK];
    409 
    410 	p = (u_char *)(&SIN6(sa)->sin6_addr);
    411 	lim = (u_char *)sa + sa->sa_len;
    412 	return prefixlen(p, lim);
    413 }
    414 
    415 int
    416 prefixlen(u_char *p, u_char *lim)
    417 {
    418 	int masklen;
    419 
    420 	for (masklen = 0; p < lim; p++) {
    421 		switch (*p) {
    422 		case 0xff:
    423 			masklen += 8;
    424 			break;
    425 		case 0xfe:
    426 			masklen += 7;
    427 			break;
    428 		case 0xfc:
    429 			masklen += 6;
    430 			break;
    431 		case 0xf8:
    432 			masklen += 5;
    433 			break;
    434 		case 0xf0:
    435 			masklen += 4;
    436 			break;
    437 		case 0xe0:
    438 			masklen += 3;
    439 			break;
    440 		case 0xc0:
    441 			masklen += 2;
    442 			break;
    443 		case 0x80:
    444 			masklen += 1;
    445 			break;
    446 		case 0x00:
    447 			break;
    448 		default:
    449 			return(-1);
    450 		}
    451 	}
    452 
    453 	return(masklen);
    454 }
    455 
    456 int
    457 rtmsg_type(char *buf)
    458 {
    459 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    460 
    461 	return(rtm->rtm_type);
    462 }
    463 
    464 int
    465 rtmsg_len(char *buf)
    466 {
    467 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    468 
    469 	return(rtm->rtm_msglen);
    470 }
    471 
    472 int
    473 ifmsg_len(char *buf)
    474 {
    475 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    476 
    477 	return(ifm->ifm_msglen);
    478 }
    479 
    480 /*
    481  * alloc buffer and get if_msghdrs block from kernel,
    482  * and put them into the buffer
    483  */
    484 static void
    485 get_iflist(char **buf, size_t *size)
    486 {
    487 	int mib[6];
    488 
    489 	mib[0] = CTL_NET;
    490 	mib[1] = PF_ROUTE;
    491 	mib[2] = 0;
    492 	mib[3] = AF_INET6;
    493 	mib[4] = NET_RT_IFLIST;
    494 	mib[5] = 0;
    495 
    496 	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
    497 		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
    498 		       __FUNCTION__);
    499 		exit(1);
    500 	}
    501 	if ((*buf = malloc(*size)) == NULL) {
    502 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
    503 		exit(1);
    504 	}
    505 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
    506 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
    507 		       __FUNCTION__);
    508 		exit(1);
    509 	}
    510 	return;
    511 }
    512 
    513 /*
    514  * alloc buffer and parse if_msghdrs block passed as arg,
    515  * and init the buffer as list of pointers ot each of the if_msghdr.
    516  */
    517 static void
    518 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
    519 {
    520 	int iflentry_size, malloc_size;
    521 	struct if_msghdr *ifm;
    522 	struct ifa_msghdr *ifam;
    523 	char *lim;
    524 
    525 	/*
    526 	 * Estimate least size of an iflist entry, to be obtained from kernel.
    527 	 * Should add sizeof(sockaddr) ??
    528 	 */
    529 	iflentry_size = sizeof(struct if_msghdr);
    530 	/* roughly estimate max list size of pointers to each if_msghdr */
    531 	malloc_size = (bufsize/iflentry_size) * sizeof(size_t);
    532 	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
    533 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
    534 		exit(1);
    535 	}
    536 
    537 	lim = buf + bufsize;
    538 	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
    539 		if (ifm->ifm_msglen == 0) {
    540 			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
    541 			       "(buf=%p lim=%p ifm=%p)", __FUNCTION__,
    542 			       buf, lim, ifm);
    543 			return;
    544 		}
    545 
    546 		if (ifm->ifm_type == RTM_IFINFO) {
    547 			(*ifmlist_p)[ifm->ifm_index] = ifm;
    548 		} else {
    549 			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
    550 			       "expected %d, got %d\n msglen = %d\n"
    551 			       "buf:%p, ifm:%p, lim:%p\n",
    552 			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
    553 			       buf, ifm, lim);
    554 			exit (1);
    555 		}
    556 		for (ifam = (struct ifa_msghdr *)
    557 			((char *)ifm + ifm->ifm_msglen);
    558 		     ifam < (struct ifa_msghdr *)lim;
    559 		     ifam = (struct ifa_msghdr *)
    560 		     	((char *)ifam + ifam->ifam_msglen)) {
    561 			/* just for safety */
    562 			if (!ifam->ifam_msglen) {
    563 				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
    564 				       "(buf=%p lim=%p ifam=%p)", __FUNCTION__,
    565 				       buf, lim, ifam);
    566 				return;
    567 			}
    568 			if (ifam->ifam_type != RTM_NEWADDR)
    569 				break;
    570 		}
    571 		ifm = (struct if_msghdr *)ifam;
    572 	}
    573 }
    574 
    575 void
    576 init_iflist()
    577 {
    578 	if (ifblock) {
    579 		free(ifblock);
    580 		ifblock_size = 0;
    581 	}
    582 	if (iflist)
    583 		free(iflist);
    584 	/* get iflist block from kernel */
    585 	get_iflist(&ifblock, &ifblock_size);
    586 
    587 	/* make list of pointers to each if_msghdr */
    588 	parse_iflist(&iflist, ifblock, ifblock_size);
    589 }
    590