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if.c revision 1.11 
      1 /*	$NetBSD: if.c,v 1.11 2002/05/21 14:22:05 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, "<%s> unsupported link type(%d)",
    241 		    __FUNCTION__, sdl->sdl_type);
    242 		exit(1);
    243 	}
    244 
    245 	return;
    246 }
    247 
    248 int
    249 rtbuf_len()
    250 {
    251 	size_t len;
    252 
    253 	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
    254 
    255 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
    256 		return(-1);
    257 
    258 	return(len);
    259 }
    260 
    261 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    262 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    263 #define SDL(s) ((struct sockaddr_dl *)(s))
    264 char *
    265 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    266 {
    267 	struct rt_msghdr *rtm;
    268 	struct ifa_msghdr *ifam;
    269 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    270 
    271 	*lenp = 0;
    272 	for (rtm = (struct rt_msghdr *)buf;
    273 	     rtm < (struct rt_msghdr *)lim;
    274 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    275 		/* just for safety */
    276 		if (!rtm->rtm_msglen) {
    277 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    278 				"(buf=%p lim=%p rtm=%p)", __FUNCTION__,
    279 				buf, lim, rtm);
    280 			break;
    281 		}
    282 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    283 			continue;
    284 		}
    285 
    286 		switch (rtm->rtm_type) {
    287 		case RTM_GET:
    288 		case RTM_ADD:
    289 		case RTM_DELETE:
    290 			/* address related checks */
    291 			sa = (struct sockaddr *)(rtm + 1);
    292 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    293 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    294 			    dst->sa_family != AF_INET6)
    295 				continue;
    296 
    297 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    298 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    299 				continue;
    300 
    301 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    302 			    gw->sa_family != AF_LINK)
    303 				continue;
    304 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    305 				continue;
    306 
    307 			if (rti_info[RTAX_NETMASK] == NULL)
    308 				continue;
    309 
    310 			/* found */
    311 			*lenp = rtm->rtm_msglen;
    312 			return (char *)rtm;
    313 			/* NOTREACHED */
    314 		case RTM_NEWADDR:
    315 		case RTM_DELADDR:
    316 			ifam = (struct ifa_msghdr *)rtm;
    317 
    318 			/* address related checks */
    319 			sa = (struct sockaddr *)(ifam + 1);
    320 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    321 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    322 			    (ifa->sa_family != AF_INET &&
    323 			     ifa->sa_family != AF_INET6))
    324 				continue;
    325 
    326 			if (ifa->sa_family == AF_INET6 &&
    327 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    328 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    329 				continue;
    330 
    331 			if (ifindex && ifam->ifam_index != ifindex)
    332 				continue;
    333 
    334 			/* found */
    335 			*lenp = ifam->ifam_msglen;
    336 			return (char *)rtm;
    337 			/* NOTREACHED */
    338 		case RTM_IFINFO:
    339 			/* found */
    340 			*lenp = rtm->rtm_msglen;
    341 			return (char *)rtm;
    342 			/* NOTREACHED */
    343 		}
    344 	}
    345 
    346 	return (char *)rtm;
    347 }
    348 #undef FILTER_MATCH
    349 
    350 struct in6_addr *
    351 get_addr(char *buf)
    352 {
    353 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    354 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    355 
    356 	sa = (struct sockaddr *)(rtm + 1);
    357 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    358 
    359 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    360 }
    361 
    362 int
    363 get_rtm_ifindex(char *buf)
    364 {
    365 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    366 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    367 
    368 	sa = (struct sockaddr *)(rtm + 1);
    369 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    370 
    371 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    372 }
    373 
    374 int
    375 get_ifm_ifindex(char *buf)
    376 {
    377 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    378 
    379 	return ((int)ifm->ifm_index);
    380 }
    381 
    382 int
    383 get_ifam_ifindex(char *buf)
    384 {
    385 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    386 
    387 	return ((int)ifam->ifam_index);
    388 }
    389 
    390 int
    391 get_ifm_flags(char *buf)
    392 {
    393 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    394 
    395 	return (ifm->ifm_flags);
    396 }
    397 
    398 int
    399 get_prefixlen(char *buf)
    400 {
    401 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    402 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    403 	u_char *p, *lim;
    404 
    405 	sa = (struct sockaddr *)(rtm + 1);
    406 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    407 	sa = rti_info[RTAX_NETMASK];
    408 
    409 	p = (u_char *)(&SIN6(sa)->sin6_addr);
    410 	lim = (u_char *)sa + sa->sa_len;
    411 	return prefixlen(p, lim);
    412 }
    413 
    414 int
    415 prefixlen(u_char *p, u_char *lim)
    416 {
    417 	int masklen;
    418 
    419 	for (masklen = 0; p < lim; p++) {
    420 		switch (*p) {
    421 		case 0xff:
    422 			masklen += 8;
    423 			break;
    424 		case 0xfe:
    425 			masklen += 7;
    426 			break;
    427 		case 0xfc:
    428 			masklen += 6;
    429 			break;
    430 		case 0xf8:
    431 			masklen += 5;
    432 			break;
    433 		case 0xf0:
    434 			masklen += 4;
    435 			break;
    436 		case 0xe0:
    437 			masklen += 3;
    438 			break;
    439 		case 0xc0:
    440 			masklen += 2;
    441 			break;
    442 		case 0x80:
    443 			masklen += 1;
    444 			break;
    445 		case 0x00:
    446 			break;
    447 		default:
    448 			return(-1);
    449 		}
    450 	}
    451 
    452 	return(masklen);
    453 }
    454 
    455 int
    456 rtmsg_type(char *buf)
    457 {
    458 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    459 
    460 	return(rtm->rtm_type);
    461 }
    462 
    463 int
    464 rtmsg_len(char *buf)
    465 {
    466 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    467 
    468 	return(rtm->rtm_msglen);
    469 }
    470 
    471 int
    472 ifmsg_len(char *buf)
    473 {
    474 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    475 
    476 	return(ifm->ifm_msglen);
    477 }
    478 
    479 /*
    480  * alloc buffer and get if_msghdrs block from kernel,
    481  * and put them into the buffer
    482  */
    483 static void
    484 get_iflist(char **buf, size_t *size)
    485 {
    486 	int mib[6];
    487 
    488 	mib[0] = CTL_NET;
    489 	mib[1] = PF_ROUTE;
    490 	mib[2] = 0;
    491 	mib[3] = AF_INET6;
    492 	mib[4] = NET_RT_IFLIST;
    493 	mib[5] = 0;
    494 
    495 	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
    496 		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
    497 		       __FUNCTION__);
    498 		exit(1);
    499 	}
    500 	if ((*buf = malloc(*size)) == NULL) {
    501 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
    502 		exit(1);
    503 	}
    504 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
    505 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
    506 		       __FUNCTION__);
    507 		exit(1);
    508 	}
    509 	return;
    510 }
    511 
    512 /*
    513  * alloc buffer and parse if_msghdrs block passed as arg,
    514  * and init the buffer as list of pointers ot each of the if_msghdr.
    515  */
    516 static void
    517 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
    518 {
    519 	int iflentry_size, malloc_size;
    520 	struct if_msghdr *ifm;
    521 	struct ifa_msghdr *ifam;
    522 	char *lim;
    523 
    524 	/*
    525 	 * Estimate least size of an iflist entry, to be obtained from kernel.
    526 	 * Should add sizeof(sockaddr) ??
    527 	 */
    528 	iflentry_size = sizeof(struct if_msghdr);
    529 	/* roughly estimate max list size of pointers to each if_msghdr */
    530 	malloc_size = (bufsize/iflentry_size) * sizeof(size_t);
    531 	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
    532 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
    533 		exit(1);
    534 	}
    535 
    536 	lim = buf + bufsize;
    537 	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
    538 		if (ifm->ifm_msglen == 0) {
    539 			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
    540 			       "(buf=%p lim=%p ifm=%p)", __FUNCTION__,
    541 			       buf, lim, ifm);
    542 			return;
    543 		}
    544 
    545 		if (ifm->ifm_type == RTM_IFINFO) {
    546 			(*ifmlist_p)[ifm->ifm_index] = ifm;
    547 		} else {
    548 			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
    549 			       "expected %d, got %d\n msglen = %d\n"
    550 			       "buf:%p, ifm:%p, lim:%p\n",
    551 			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
    552 			       buf, ifm, lim);
    553 			exit (1);
    554 		}
    555 		for (ifam = (struct ifa_msghdr *)
    556 			((char *)ifm + ifm->ifm_msglen);
    557 		     ifam < (struct ifa_msghdr *)lim;
    558 		     ifam = (struct ifa_msghdr *)
    559 		     	((char *)ifam + ifam->ifam_msglen)) {
    560 			/* just for safety */
    561 			if (!ifam->ifam_msglen) {
    562 				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
    563 				       "(buf=%p lim=%p ifam=%p)", __FUNCTION__,
    564 				       buf, lim, ifam);
    565 				return;
    566 			}
    567 			if (ifam->ifam_type != RTM_NEWADDR)
    568 				break;
    569 		}
    570 		ifm = (struct if_msghdr *)ifam;
    571 	}
    572 }
    573 
    574 void
    575 init_iflist()
    576 {
    577 	if (ifblock) {
    578 		free(ifblock);
    579 		ifblock_size = 0;
    580 	}
    581 	if (iflist)
    582 		free(iflist);
    583 	/* get iflist block from kernel */
    584 	get_iflist(&ifblock, &ifblock_size);
    585 
    586 	/* make list of pointers to each if_msghdr */
    587 	parse_iflist(&iflist, ifblock, ifblock_size);
    588 }
    589