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if.c revision 1.5 
      1 /*	$NetBSD: if.c,v 1.5 2000/05/23 11:37:59 itojun Exp $	*/
      2 /*	$KAME: if.c,v 1.8 2000/05/22 22:04:37 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 #ifdef __bsdi__
     43 # include <ifaddrs.h>
     44 #endif
     45 #ifdef __NetBSD__
     46 #include <net/if_ether.h>
     47 #endif
     48 #include <net/route.h>
     49 #include <net/if_dl.h>
     50 #include <netinet/in.h>
     51 #include <netinet/icmp6.h>
     52 #ifdef __bsdi__
     53 # include <netinet/if_ether.h>
     54 #endif
     55 #ifdef __OpenBSD__
     56 #include <netinet/if_ether.h>
     57 #endif
     58 #include <unistd.h>
     59 #include <errno.h>
     60 #include <stdlib.h>
     61 #include <string.h>
     62 #include <syslog.h>
     63 #include "rtadvd.h"
     64 #include "if.h"
     65 
     66 #define ROUNDUP(a, size) \
     67 	(((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
     68 
     69 #define NEXT_SA(ap) (ap) = (struct sockaddr *) \
     70 	((caddr_t)(ap) + ((ap)->sa_len ? ROUNDUP((ap)->sa_len,\
     71 						 sizeof(u_long)) :\
     72 			  			 sizeof(u_long)))
     73 
     74 struct if_msghdr **iflist;
     75 int iflist_init_ok;
     76 size_t ifblock_size;
     77 char *ifblock;
     78 
     79 static void get_iflist __P((char **buf, size_t *size));
     80 static void parse_iflist __P((struct if_msghdr ***ifmlist_p, char *buf,
     81 		       size_t bufsize));
     82 
     83 static void
     84 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
     85 {
     86 	int i;
     87 
     88 	for (i = 0; i < RTAX_MAX; i++) {
     89 		if (addrs & (1 << i)) {
     90 			rti_info[i] = sa;
     91 			NEXT_SA(sa);
     92 		}
     93 		else
     94 			rti_info[i] = NULL;
     95 	}
     96 }
     97 
     98 struct sockaddr_dl *
     99 if_nametosdl(char *name)
    100 {
    101 	int mib[6] = {CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
    102 	char *buf, *next, *lim;
    103 	size_t len;
    104 	struct if_msghdr *ifm;
    105 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    106 	struct sockaddr_dl *sdl = NULL, *ret_sdl;
    107 
    108 	if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
    109 		return(NULL);
    110 	if ((buf = malloc(len)) == NULL)
    111 		return(NULL);
    112 	if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
    113 		free(buf);
    114 		return(NULL);
    115 	}
    116 
    117 	lim = buf + len;
    118 	for (next = buf; next < lim; next += ifm->ifm_msglen) {
    119 		ifm = (struct if_msghdr *)next;
    120 		if (ifm->ifm_type == RTM_IFINFO) {
    121 			sa = (struct sockaddr *)(ifm + 1);
    122 			get_rtaddrs(ifm->ifm_addrs, sa, rti_info);
    123 			if ((sa = rti_info[RTAX_IFP]) != NULL) {
    124 				if (sa->sa_family == AF_LINK) {
    125 					sdl = (struct sockaddr_dl *)sa;
    126 					if (strlen(name) != sdl->sdl_nlen)
    127 						continue; /* not same len */
    128 					if (strncmp(&sdl->sdl_data[0],
    129 						    name,
    130 						    sdl->sdl_nlen) == 0) {
    131 						break;
    132 					}
    133 				}
    134 			}
    135 		}
    136 	}
    137 	if (next == lim) {
    138 		/* search failed */
    139 		free(buf);
    140 		return(NULL);
    141 	}
    142 
    143 	if ((ret_sdl = malloc(sdl->sdl_len)) == NULL)
    144 		return(NULL);
    145 	memcpy((caddr_t)ret_sdl, (caddr_t)sdl, sdl->sdl_len);
    146 	return(ret_sdl);
    147 }
    148 
    149 int
    150 if_getmtu(char *name)
    151 {
    152 #ifndef __bsdi__
    153 	struct ifreq ifr;
    154 	int s;
    155 
    156 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    157 		return(0);
    158 
    159 	ifr.ifr_addr.sa_family = AF_INET6;
    160 	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
    161 	if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
    162 		close(s);
    163 		return(0);
    164 	}
    165 
    166 	close(s);
    167 
    168 	return(ifr.ifr_mtu);
    169 #else
    170 	struct ifaddrs *ifap, *ifa;
    171 	struct if_data *ifd;
    172 
    173 	if (getifaddrs(&ifap) < 0)
    174 		return(0);
    175 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
    176 		if (strcmp(ifa->ifa_name, name) == 0) {
    177 			ifd = ifa->ifa_data;
    178 			freeifaddrs(ifap);
    179 			if (ifd)
    180 				return ifd->ifi_mtu;
    181 			else
    182 				return 0;
    183 		}
    184 	}
    185 	freeifaddrs(ifap);
    186 	return 0;
    187 #endif
    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 	return (ifr.ifr_flags);
    211 }
    212 
    213 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    214 int
    215 lladdropt_length(struct sockaddr_dl *sdl)
    216 {
    217 	switch(sdl->sdl_type) {
    218 	 case IFT_ETHER:
    219 		 return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    220 	 default:
    221 		 return(0);
    222 	}
    223 }
    224 
    225 void
    226 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    227 {
    228 	char *addr;
    229 
    230 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    231 
    232 	switch(sdl->sdl_type) {
    233 	 case IFT_ETHER:
    234 		 ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    235 		 addr = (char *)(ndopt + 1);
    236 		 memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    237 		 break;
    238 	 default:
    239 		 syslog(LOG_ERR,
    240 			"<%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 int
    262 get_rtinfo(char *buf, size_t *len)
    263 {
    264 	int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};
    265 
    266 	if (sysctl(mib, 6, buf, len, NULL, 0) < 0)
    267 		return(-1);
    268 
    269 	return(0);
    270 }
    271 
    272 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    273 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    274 #define SDL(s) ((struct sockaddr_dl *)(s))
    275 char *
    276 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    277 {
    278 	struct rt_msghdr *rtm;
    279 	struct ifa_msghdr *ifam;
    280 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    281 
    282 	*lenp = 0;
    283 	for (rtm = (struct rt_msghdr *)buf;
    284 	     rtm < (struct rt_msghdr *)lim;
    285 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    286 		/* just for safety */
    287 		if (!rtm->rtm_msglen) {
    288 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    289 				"(buf=%p lim=%p rtm=%p)", __FUNCTION__,
    290 				buf, lim, rtm);
    291 			break;
    292 		}
    293 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    294 			continue;
    295 		}
    296 
    297 		switch (rtm->rtm_type) {
    298 		case RTM_GET:
    299 		case RTM_ADD:
    300 		case RTM_DELETE:
    301 			/* address related checks */
    302 			sa = (struct sockaddr *)(rtm + 1);
    303 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    304 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    305 			    dst->sa_family != AF_INET6)
    306 				continue;
    307 
    308 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    309 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    310 				continue;
    311 
    312 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    313 			    gw->sa_family != AF_LINK)
    314 				continue;
    315 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    316 				continue;
    317 
    318 			if (rti_info[RTAX_NETMASK] == NULL)
    319 				continue;
    320 
    321 			/* found */
    322 			*lenp = rtm->rtm_msglen;
    323 			return (char *)rtm;
    324 			/* NOTREACHED */
    325 		case RTM_NEWADDR:
    326 		case RTM_DELADDR:
    327 			ifam = (struct ifa_msghdr *)rtm;
    328 
    329 			/* address related checks */
    330 			sa = (struct sockaddr *)(ifam + 1);
    331 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    332 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    333 			    (ifa->sa_family != AF_INET &&
    334 			     ifa->sa_family != AF_INET6))
    335 				continue;
    336 
    337 			if (ifa->sa_family == AF_INET6 &&
    338 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    339 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    340 				continue;
    341 
    342 			if (ifindex && ifam->ifam_index != ifindex)
    343 				continue;
    344 
    345 			/* found */
    346 			*lenp = ifam->ifam_msglen;
    347 			return (char *)rtm;
    348 			/* NOTREACHED */
    349 		case RTM_IFINFO:
    350 			/* found */
    351 			*lenp = rtm->rtm_msglen;
    352 			return (char *)rtm;
    353 			/* NOTREACHED */
    354 		}
    355 	}
    356 
    357 	return (char *)rtm;
    358 }
    359 #undef FILTER_MATCH(type, filter)
    360 
    361 struct in6_addr *
    362 get_addr(char *buf)
    363 {
    364 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    365 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    366 
    367 	sa = (struct sockaddr *)(rtm + 1);
    368 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    369 
    370 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    371 }
    372 
    373 int
    374 get_rtm_ifindex(char *buf)
    375 {
    376 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    377 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    378 
    379 	sa = (struct sockaddr *)(rtm + 1);
    380 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    381 
    382 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    383 }
    384 
    385 int
    386 get_ifm_ifindex(char *buf)
    387 {
    388 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    389 
    390 	return ((int)ifm->ifm_index);
    391 }
    392 
    393 int
    394 get_ifam_ifindex(char *buf)
    395 {
    396 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    397 
    398 	return ((int)ifam->ifam_index);
    399 }
    400 
    401 int
    402 get_ifm_flags(char *buf)
    403 {
    404 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    405 
    406 	return (ifm->ifm_flags);
    407 }
    408 
    409 int
    410 get_prefixlen(char *buf)
    411 {
    412 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    413 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    414 	int masklen;
    415 	u_char *p, *lim;
    416 
    417 	sa = (struct sockaddr *)(rtm + 1);
    418 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    419 	sa = rti_info[RTAX_NETMASK];
    420 
    421 	p = (u_char *)(&SIN6(sa)->sin6_addr);
    422 	lim = (u_char *)sa + sa->sa_len;
    423 	for (masklen = 0; p < lim; p++) {
    424 		switch (*p) {
    425 		case 0xff:
    426 			masklen += 8;
    427 			break;
    428 		case 0xfe:
    429 			masklen += 7;
    430 			break;
    431 		case 0xfc:
    432 			masklen += 6;
    433 			break;
    434 		case 0xf8:
    435 			masklen += 5;
    436 			break;
    437 		case 0xf0:
    438 			masklen += 4;
    439 			break;
    440 		case 0xe0:
    441 			masklen += 3;
    442 			break;
    443 		case 0xc0:
    444 			masklen += 2;
    445 			break;
    446 		case 0x80:
    447 			masklen += 1;
    448 			break;
    449 		case 0x00:
    450 			break;
    451 		default:
    452 			return(-1);
    453 		}
    454 	}
    455 
    456 	return(masklen);
    457 }
    458 
    459 int
    460 rtmsg_type(char *buf)
    461 {
    462 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    463 
    464 	return(rtm->rtm_type);
    465 }
    466 
    467 int
    468 rtmsg_len(char *buf)
    469 {
    470 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    471 
    472 	return(rtm->rtm_msglen);
    473 }
    474 
    475 int
    476 ifmsg_len(char *buf)
    477 {
    478 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    479 
    480 	return(ifm->ifm_msglen);
    481 }
    482 
    483 /*
    484  * alloc buffer and get if_msghdrs block from kernel,
    485  * and put them into the buffer
    486  */
    487 static void
    488 get_iflist(char **buf, size_t *size)
    489 {
    490 	int mib[6];
    491 
    492 	mib[0] = CTL_NET;
    493 	mib[1] = PF_ROUTE;
    494 	mib[2] = 0;
    495 	mib[3] = AF_INET6;
    496 	mib[4] = NET_RT_IFLIST;
    497 	mib[5] = 0;
    498 
    499 	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
    500 		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
    501 		       __FUNCTION__);
    502 		exit(1);
    503 	}
    504 	if ((*buf = malloc(*size)) == NULL) {
    505 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
    506 		exit(1);
    507 	}
    508 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
    509 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
    510 		       __FUNCTION__);
    511 		exit(1);
    512 	}
    513 	return;
    514 }
    515 
    516 /*
    517  * alloc buffer and parse if_msghdrs block passed as arg,
    518  * and init the buffer as list of pointers ot each of the if_msghdr.
    519  */
    520 static void
    521 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
    522 {
    523 	int iflentry_size, malloc_size;
    524 	struct if_msghdr *ifm;
    525 	struct ifa_msghdr *ifam;
    526 	char *lim;
    527 
    528 	/*
    529 	 * Estimate least size of an iflist entry, to be obtained from kernel.
    530 	 * Should add sizeof(sockaddr) ??
    531 	 */
    532 	iflentry_size = sizeof(struct if_msghdr);
    533 	/* roughly estimate max list size of pointers to each if_msghdr */
    534 	malloc_size = (bufsize/iflentry_size) * sizeof(size_t);
    535 	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
    536 		syslog(LOG_ERR, "<%s> malloc failed", __FUNCTION__);
    537 		exit(1);
    538 	}
    539 
    540 	lim = buf + bufsize;
    541 	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
    542 		if (ifm->ifm_msglen == 0) {
    543 			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
    544 			       "(buf=%p lim=%p ifm=%p)", __FUNCTION__,
    545 			       buf, lim, ifm);
    546 			return;
    547 		}
    548 
    549 		if (ifm->ifm_type == RTM_IFINFO) {
    550 			(*ifmlist_p)[ifm->ifm_index] = ifm;
    551 		} else {
    552 			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
    553 			       "expected %d, got %d\n msglen = %d\n"
    554 			       "buf:%p, ifm:%p, lim:%p\n",
    555 			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
    556 			       buf, ifm, lim);
    557 			exit (1);
    558 		}
    559 		for (ifam = (struct ifa_msghdr *)
    560 			((char *)ifm + ifm->ifm_msglen);
    561 		     ifam < (struct ifa_msghdr *)lim;
    562 		     ifam = (struct ifa_msghdr *)
    563 		     	((char *)ifam + ifam->ifam_msglen)) {
    564 			/* just for safety */
    565 			if (!ifam->ifam_msglen) {
    566 				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
    567 				       "(buf=%p lim=%p ifam=%p)", __FUNCTION__,
    568 				       buf, lim, ifam);
    569 				return;
    570 			}
    571 			if (ifam->ifam_type != RTM_NEWADDR)
    572 				break;
    573 		}
    574 		ifm = (struct if_msghdr *)ifam;
    575 	}
    576 }
    577 
    578 void
    579 init_iflist()
    580 {
    581 	if (ifblock) {
    582 		free(ifblock);
    583 		ifblock_size = 0;
    584 	}
    585 	if (iflist)
    586 		free(iflist);
    587 	/* get iflist block from kernel */
    588 	get_iflist(&ifblock, &ifblock_size);
    589 
    590 	/* make list of pointers to each if_msghdr */
    591 	parse_iflist(&iflist, ifblock, ifblock_size);
    592 
    593 }
    594