Home | History | Annotate | Line # | Download | only in rtadvd
if.c revision 1.18.16.1 
      1 /*	$NetBSD: if.c,v 1.18.16.1 2008/02/22 02:53:34 keiichi 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 <netinet6/in6_var.h>
     46 #include <unistd.h>
     47 #include <errno.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 #include <syslog.h>
     51 #include "rtadvd.h"
     52 #include "if.h"
     53 
     54 #define ROUNDUP(a, size) \
     55 	(((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
     56 
     57 #define NEXT_SA(ap) (ap) = (struct sockaddr *) \
     58 	((caddr_t)(ap) + ((ap)->sa_len ? ROUNDUP((ap)->sa_len,\
     59 						 sizeof(u_long)) :\
     60 			  			 sizeof(u_long)))
     61 
     62 struct if_msghdr **iflist;
     63 int iflist_init_ok;
     64 size_t ifblock_size;
     65 char *ifblock;
     66 
     67 static void get_iflist __P((char **buf, size_t *size));
     68 static void parse_iflist __P((struct if_msghdr ***ifmlist_p, char *buf,
     69 		       size_t bufsize));
     70 
     71 static void
     72 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
     73 {
     74 	int i;
     75 
     76 	for (i = 0; i < RTAX_MAX; i++) {
     77 		if (addrs & (1 << i)) {
     78 			rti_info[i] = sa;
     79 			NEXT_SA(sa);
     80 		}
     81 		else
     82 			rti_info[i] = NULL;
     83 	}
     84 }
     85 
     86 struct sockaddr_dl *
     87 if_nametosdl(char *name)
     88 {
     89 	struct ifaddrs *ifap, *ifa;
     90 	struct sockaddr_dl *sdl;
     91 
     92 	if (getifaddrs(&ifap) != 0)
     93 		return (NULL);
     94 
     95 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
     96 		if (strcmp(ifa->ifa_name, name) != 0)
     97 			continue;
     98 		if (ifa->ifa_addr->sa_family != AF_LINK)
     99 			continue;
    100 
    101 		sdl = malloc(ifa->ifa_addr->sa_len);
    102 		if (!sdl)
    103 			continue;	/*XXX*/
    104 
    105 		memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
    106 		freeifaddrs(ifap);
    107 		return (sdl);
    108 	}
    109 
    110 	freeifaddrs(ifap);
    111 	return (NULL);
    112 }
    113 
    114 int
    115 if_getmtu(char *name)
    116 {
    117 	struct ifaddrs *ifap, *ifa;
    118 	struct if_data *ifd;
    119 	u_long mtu = 0;
    120 
    121 	if (getifaddrs(&ifap) < 0)
    122 		return(0);
    123 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
    124 		if (strcmp(ifa->ifa_name, name) == 0) {
    125 			ifd = ifa->ifa_data;
    126 			if (ifd)
    127 				mtu = ifd->ifi_mtu;
    128 			break;
    129 		}
    130 	}
    131 	freeifaddrs(ifap);
    132 
    133 #ifdef SIOCGIFMTU		/* XXX: this ifdef may not be necessary */
    134 	if (mtu == 0) {
    135 		struct ifreq ifr;
    136 		int s;
    137 
    138 		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    139 			return(0);
    140 
    141 		ifr.ifr_addr.sa_family = AF_INET6;
    142 		strncpy(ifr.ifr_name, name,
    143 			sizeof(ifr.ifr_name));
    144 		if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) < 0) {
    145 			close(s);
    146 			return(0);
    147 		}
    148 		close(s);
    149 
    150 		mtu = ifr.ifr_mtu;
    151 	}
    152 #endif
    153 
    154 	return(mtu);
    155 }
    156 
    157 int
    158 if_getifaflag(char *name, struct in6_addr *addr)
    159 {
    160 	struct in6_ifreq ifr;
    161 	int s;
    162 
    163 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    164 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
    165 			strerror(errno));
    166 		return (0);
    167 	}
    168 
    169 	(void) memset(&ifr, 0, sizeof(ifr));
    170 	(void) strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
    171 	ifr.ifr_addr.sin6_family = AF_INET6;
    172 	ifr.ifr_addr.sin6_addr = *addr;
    173 	if (ioctl(s, SIOCGIFAFLAG_IN6, (caddr_t)&ifr) < 0) {
    174 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFAFLAG_IN6: failed for %s",
    175 			__func__, ifr.ifr_name);
    176 		close(s);
    177 		return (0);
    178 	}
    179 	close(s);
    180 	return (ifr.ifr_ifru.ifru_flags6);
    181 }
    182 
    183 /* give interface index and its old flags, then new flags returned */
    184 int
    185 if_getflags(int ifindex, int oifflags)
    186 {
    187 	struct ifreq ifr;
    188 	int s;
    189 
    190 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    191 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
    192 		       strerror(errno));
    193 		return (oifflags & ~IFF_UP);
    194 	}
    195 
    196 	if_indextoname(ifindex, ifr.ifr_name);
    197 	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
    198 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    199 		       __func__, ifr.ifr_name);
    200 		close(s);
    201 		return (oifflags & ~IFF_UP);
    202 	}
    203 	close(s);
    204 	return (ifr.ifr_flags);
    205 }
    206 
    207 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    208 int
    209 lladdropt_length(struct sockaddr_dl *sdl)
    210 {
    211 	switch (sdl->sdl_type) {
    212 	case IFT_ETHER:
    213 	case IFT_FDDI:
    214 		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    215 	default:
    216 		return(0);
    217 	}
    218 }
    219 
    220 void
    221 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    222 {
    223 	char *addr;
    224 
    225 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    226 
    227 	switch (sdl->sdl_type) {
    228 	case IFT_ETHER:
    229 	case IFT_FDDI:
    230 		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    231 		addr = (char *)(ndopt + 1);
    232 		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    233 		break;
    234 	default:
    235 		syslog(LOG_ERR, "<%s> unsupported link type(%d)",
    236 		    __func__, sdl->sdl_type);
    237 		exit(1);
    238 	}
    239 
    240 	return;
    241 }
    242 
    243 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    244 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    245 #define SDL(s) ((struct sockaddr_dl *)(s))
    246 char *
    247 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    248 {
    249 	struct rt_msghdr *rtm;
    250 	struct ifa_msghdr *ifam;
    251 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    252 
    253 	*lenp = 0;
    254 	for (rtm = (struct rt_msghdr *)buf;
    255 	     rtm < (struct rt_msghdr *)lim;
    256 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    257 		/* just for safety */
    258 		if (!rtm->rtm_msglen) {
    259 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    260 				"(buf=%p lim=%p rtm=%p)", __func__,
    261 				buf, lim, rtm);
    262 			break;
    263 		}
    264 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    265 			continue;
    266 		}
    267 
    268 		switch (rtm->rtm_type) {
    269 		case RTM_GET:
    270 		case RTM_ADD:
    271 		case RTM_DELETE:
    272 			/* address related checks */
    273 			sa = (struct sockaddr *)(rtm + 1);
    274 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    275 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    276 			    dst->sa_family != AF_INET6)
    277 				continue;
    278 
    279 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    280 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    281 				continue;
    282 
    283 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    284 			    gw->sa_family != AF_LINK)
    285 				continue;
    286 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    287 				continue;
    288 
    289 			if (rti_info[RTAX_NETMASK] == NULL)
    290 				continue;
    291 
    292 			/* found */
    293 			*lenp = rtm->rtm_msglen;
    294 			return (char *)rtm;
    295 			/* NOTREACHED */
    296 		case RTM_NEWADDR:
    297 		case RTM_DELADDR:
    298 			ifam = (struct ifa_msghdr *)rtm;
    299 
    300 			/* address related checks */
    301 			sa = (struct sockaddr *)(ifam + 1);
    302 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    303 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    304 			    (ifa->sa_family != AF_INET &&
    305 			     ifa->sa_family != AF_INET6))
    306 				continue;
    307 
    308 			if (ifa->sa_family == AF_INET6 &&
    309 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    310 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    311 				continue;
    312 
    313 			if (ifindex && ifam->ifam_index != ifindex)
    314 				continue;
    315 
    316 			/* found */
    317 			*lenp = ifam->ifam_msglen;
    318 			return (char *)rtm;
    319 			/* NOTREACHED */
    320 		case RTM_IFINFO:
    321 			/* found */
    322 			*lenp = rtm->rtm_msglen;
    323 			return (char *)rtm;
    324 			/* NOTREACHED */
    325 		}
    326 	}
    327 
    328 	return (char *)rtm;
    329 }
    330 #undef FILTER_MATCH
    331 
    332 struct in6_addr *
    333 get_addr(char *buf)
    334 {
    335 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    336 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    337 
    338 	sa = (struct sockaddr *)(rtm + 1);
    339 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    340 
    341 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    342 }
    343 
    344 int
    345 get_rtm_ifindex(char *buf)
    346 {
    347 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    348 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    349 
    350 	sa = (struct sockaddr *)(rtm + 1);
    351 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    352 
    353 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    354 }
    355 
    356 int
    357 get_ifm_ifindex(char *buf)
    358 {
    359 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    360 
    361 	return ((int)ifm->ifm_index);
    362 }
    363 
    364 int
    365 get_ifam_ifindex(char *buf)
    366 {
    367 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    368 
    369 	return ((int)ifam->ifam_index);
    370 }
    371 
    372 int
    373 get_ifm_flags(char *buf)
    374 {
    375 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    376 
    377 	return (ifm->ifm_flags);
    378 }
    379 
    380 int
    381 get_prefixlen(char *buf)
    382 {
    383 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    384 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    385 	u_char *p, *lim;
    386 
    387 	sa = (struct sockaddr *)(rtm + 1);
    388 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    389 	sa = rti_info[RTAX_NETMASK];
    390 
    391 	p = (u_char *)(&SIN6(sa)->sin6_addr);
    392 	lim = (u_char *)sa + sa->sa_len;
    393 	return prefixlen(p, lim);
    394 }
    395 
    396 int
    397 prefixlen(u_char *p, u_char *lim)
    398 {
    399 	int masklen;
    400 
    401 	for (masklen = 0; p < lim; p++) {
    402 		switch (*p) {
    403 		case 0xff:
    404 			masklen += 8;
    405 			break;
    406 		case 0xfe:
    407 			masklen += 7;
    408 			break;
    409 		case 0xfc:
    410 			masklen += 6;
    411 			break;
    412 		case 0xf8:
    413 			masklen += 5;
    414 			break;
    415 		case 0xf0:
    416 			masklen += 4;
    417 			break;
    418 		case 0xe0:
    419 			masklen += 3;
    420 			break;
    421 		case 0xc0:
    422 			masklen += 2;
    423 			break;
    424 		case 0x80:
    425 			masklen += 1;
    426 			break;
    427 		case 0x00:
    428 			break;
    429 		default:
    430 			return(-1);
    431 		}
    432 	}
    433 
    434 	return(masklen);
    435 }
    436 
    437 int
    438 rtmsg_type(char *buf)
    439 {
    440 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    441 
    442 	return(rtm->rtm_type);
    443 }
    444 
    445 int
    446 rtmsg_len(char *buf)
    447 {
    448 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    449 
    450 	return(rtm->rtm_msglen);
    451 }
    452 
    453 int
    454 ifmsg_len(char *buf)
    455 {
    456 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    457 
    458 	return(ifm->ifm_msglen);
    459 }
    460 
    461 /*
    462  * alloc buffer and get if_msghdrs block from kernel,
    463  * and put them into the buffer
    464  */
    465 static void
    466 get_iflist(char **buf, size_t *size)
    467 {
    468 	int mib[6];
    469 
    470 	mib[0] = CTL_NET;
    471 	mib[1] = PF_ROUTE;
    472 	mib[2] = 0;
    473 	mib[3] = AF_INET6;
    474 	mib[4] = NET_RT_IFLIST;
    475 	mib[5] = 0;
    476 
    477 	if (sysctl(mib, 6, NULL, size, NULL, 0) < 0) {
    478 		syslog(LOG_ERR, "<%s> sysctl: iflist size get failed",
    479 		       __func__);
    480 		exit(1);
    481 	}
    482 	if ((*buf = malloc(*size)) == NULL) {
    483 		syslog(LOG_ERR, "<%s> malloc failed", __func__);
    484 		exit(1);
    485 	}
    486 	if (sysctl(mib, 6, *buf, size, NULL, 0) < 0) {
    487 		syslog(LOG_ERR, "<%s> sysctl: iflist get failed",
    488 		       __func__);
    489 		exit(1);
    490 	}
    491 	return;
    492 }
    493 
    494 /*
    495  * alloc buffer and parse if_msghdrs block passed as arg,
    496  * and init the buffer as list of pointers ot each of the if_msghdr.
    497  */
    498 static void
    499 parse_iflist(struct if_msghdr ***ifmlist_p, char *buf, size_t bufsize)
    500 {
    501 	int iflentry_size, malloc_size;
    502 	struct if_msghdr *ifm;
    503 	struct ifa_msghdr *ifam;
    504 	char *lim;
    505 
    506 	/*
    507 	 * Estimate least size of an iflist entry, to be obtained from kernel.
    508 	 * Should add sizeof(sockaddr) ??
    509 	 */
    510 	iflentry_size = sizeof(struct if_msghdr);
    511 	/* roughly estimate max list size of pointers to each if_msghdr */
    512 	malloc_size = (bufsize/iflentry_size) * sizeof(void *);
    513 	if ((*ifmlist_p = (struct if_msghdr **)malloc(malloc_size)) == NULL) {
    514 		syslog(LOG_ERR, "<%s> malloc failed", __func__);
    515 		exit(1);
    516 	}
    517 
    518 	lim = buf + bufsize;
    519 	for (ifm = (struct if_msghdr *)buf; ifm < (struct if_msghdr *)lim;) {
    520 		if (ifm->ifm_msglen == 0) {
    521 			syslog(LOG_WARNING, "<%s> ifm_msglen is 0 "
    522 			       "(buf=%p lim=%p ifm=%p)", __func__,
    523 			       buf, lim, ifm);
    524 			return;
    525 		}
    526 
    527 		if (ifm->ifm_type == RTM_IFINFO) {
    528 			(*ifmlist_p)[ifm->ifm_index] = ifm;
    529 		} else {
    530 			syslog(LOG_ERR, "out of sync parsing NET_RT_IFLIST\n"
    531 			       "expected %d, got %d\n msglen = %d\n"
    532 			       "buf:%p, ifm:%p, lim:%p\n",
    533 			       RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen,
    534 			       buf, ifm, lim);
    535 			exit (1);
    536 		}
    537 		for (ifam = (struct ifa_msghdr *)
    538 			((char *)ifm + ifm->ifm_msglen);
    539 		     ifam < (struct ifa_msghdr *)lim;
    540 		     ifam = (struct ifa_msghdr *)
    541 		     	((char *)ifam + ifam->ifam_msglen)) {
    542 			/* just for safety */
    543 			if (!ifam->ifam_msglen) {
    544 				syslog(LOG_WARNING, "<%s> ifa_msglen is 0 "
    545 				       "(buf=%p lim=%p ifam=%p)", __func__,
    546 				       buf, lim, ifam);
    547 				return;
    548 			}
    549 			if (ifam->ifam_type != RTM_NEWADDR)
    550 				break;
    551 		}
    552 		ifm = (struct if_msghdr *)ifam;
    553 	}
    554 }
    555 
    556 void
    557 init_iflist()
    558 {
    559 	if (ifblock) {
    560 		free(ifblock);
    561 		ifblock_size = 0;
    562 	}
    563 	if (iflist)
    564 		free(iflist);
    565 	/* get iflist block from kernel */
    566 	get_iflist(&ifblock, &ifblock_size);
    567 
    568 	/* make list of pointers to each if_msghdr */
    569 	parse_iflist(&iflist, ifblock, ifblock_size);
    570 }
    571