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if.c revision 1.21.6.1 
      1 /*	$NetBSD: if.c,v 1.21.6.1 2013/02/25 00:30:48 tls 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/queue.h>
     35 #include <sys/socket.h>
     36 #include <sys/sysctl.h>
     37 #include <sys/ioctl.h>
     38 #include <net/if.h>
     39 #include <net/if_types.h>
     40 #include <ifaddrs.h>
     41 #ifdef __FreeBSD__
     42 #include <net/ethernet.h>
     43 #else
     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 #include <unistd.h>
     51 #include <errno.h>
     52 #include <stdlib.h>
     53 #include <string.h>
     54 #include <syslog.h>
     55 
     56 #include "rtadvd.h"
     57 #include "if.h"
     58 
     59 #ifndef RT_ROUNDUP
     60 #define RT_ROUNDUP(a)							       \
     61 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
     62 #define RT_ADVANCE(x, n) (x += RT_ROUNDUP((n)->sa_len))
     63 #endif
     64 
     65 static void
     66 get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
     67 {
     68 	int i;
     69 
     70 	for (i = 0; i < RTAX_MAX; i++) {
     71 		if (addrs & (1 << i)) {
     72 			rti_info[i] = sa;
     73 			RT_ADVANCE(sa, sa);
     74 		}
     75 		else
     76 			rti_info[i] = NULL;
     77 	}
     78 }
     79 
     80 struct sockaddr_dl *
     81 if_nametosdl(const char *name)
     82 {
     83 	struct ifaddrs *ifap, *ifa;
     84 	struct sockaddr_dl *sdl;
     85 
     86 	if (getifaddrs(&ifap) != 0)
     87 		return (NULL);
     88 
     89 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
     90 		if (strcmp(ifa->ifa_name, name) != 0)
     91 			continue;
     92 		if (ifa->ifa_addr->sa_family != AF_LINK)
     93 			continue;
     94 
     95 		sdl = malloc(ifa->ifa_addr->sa_len);
     96 		if (!sdl)
     97 			continue;	/*XXX*/
     98 
     99 		memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
    100 		freeifaddrs(ifap);
    101 		return (sdl);
    102 	}
    103 
    104 	freeifaddrs(ifap);
    105 	return (NULL);
    106 }
    107 
    108 int
    109 if_getmtu(const char *name)
    110 {
    111 	struct ifreq ifr;
    112 	int s, mtu;
    113 
    114 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    115 		return 0;
    116 
    117 	memset(&ifr, 0, sizeof(ifr));
    118 	ifr.ifr_addr.sa_family = AF_INET6;
    119 	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
    120 	if (ioctl(s, SIOCGIFMTU, &ifr) != -1)
    121 		mtu = ifr.ifr_mtu;
    122 	else
    123 		mtu = 0;
    124 	close(s);
    125 
    126 	return mtu;
    127 }
    128 
    129 /* give interface index and its old flags, then new flags returned */
    130 int
    131 if_getflags(int ifindex, int oifflags)
    132 {
    133 	struct ifreq ifr;
    134 	int s;
    135 
    136 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    137 		syslog(LOG_ERR, "<%s> socket: %s", __func__,
    138 		       strerror(errno));
    139 		return (oifflags & ~IFF_UP);
    140 	}
    141 
    142 	memset(&ifr, 0, sizeof(ifr));
    143 	if_indextoname(ifindex, ifr.ifr_name);
    144 	if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
    145 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    146 		       __func__, ifr.ifr_name);
    147 		close(s);
    148 		return (oifflags & ~IFF_UP);
    149 	}
    150 	close(s);
    151 	return (ifr.ifr_flags);
    152 }
    153 
    154 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    155 int
    156 lladdropt_length(struct sockaddr_dl *sdl)
    157 {
    158 	switch (sdl->sdl_type) {
    159 	case IFT_ETHER:
    160 	case IFT_FDDI:
    161 		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    162 	default:
    163 		return(0);
    164 	}
    165 }
    166 
    167 void
    168 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    169 {
    170 	char *addr;
    171 
    172 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    173 
    174 	switch (sdl->sdl_type) {
    175 	case IFT_ETHER:
    176 	case IFT_FDDI:
    177 		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    178 		addr = (char *)(ndopt + 1);
    179 		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    180 		break;
    181 	default:
    182 		syslog(LOG_ERR, "<%s> unsupported link type(%d)",
    183 		    __func__, sdl->sdl_type);
    184 		exit(1);
    185 	}
    186 
    187 	return;
    188 }
    189 
    190 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    191 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    192 #define SDL(s) ((struct sockaddr_dl *)(s))
    193 char *
    194 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    195 {
    196 	struct rt_msghdr *rtm;
    197 	struct ifa_msghdr *ifam;
    198 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    199 
    200 	*lenp = 0;
    201 	for (rtm = (struct rt_msghdr *)buf;
    202 	     rtm < (struct rt_msghdr *)lim;
    203 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    204 		/* just for safety */
    205 		if (!rtm->rtm_msglen) {
    206 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    207 				"(buf=%p lim=%p rtm=%p)", __func__,
    208 				buf, lim, rtm);
    209 			break;
    210 		}
    211 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    212 			continue;
    213 		}
    214 
    215 		switch (rtm->rtm_type) {
    216 		case RTM_GET:
    217 		case RTM_ADD:
    218 		case RTM_DELETE:
    219 			/* address related checks */
    220 			sa = (struct sockaddr *)(rtm + 1);
    221 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    222 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    223 			    dst->sa_family != AF_INET6)
    224 				continue;
    225 
    226 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    227 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    228 				continue;
    229 
    230 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    231 			    gw->sa_family != AF_LINK)
    232 				continue;
    233 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    234 				continue;
    235 
    236 			if (rti_info[RTAX_NETMASK] == NULL)
    237 				continue;
    238 
    239 			/* found */
    240 			*lenp = rtm->rtm_msglen;
    241 			return (char *)rtm;
    242 			/* NOTREACHED */
    243 		case RTM_NEWADDR:
    244 		case RTM_DELADDR:
    245 			ifam = (struct ifa_msghdr *)rtm;
    246 
    247 			/* address related checks */
    248 			sa = (struct sockaddr *)(ifam + 1);
    249 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    250 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    251 			    (ifa->sa_family != AF_INET &&
    252 			     ifa->sa_family != AF_INET6))
    253 				continue;
    254 
    255 			if (ifa->sa_family == AF_INET6 &&
    256 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    257 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    258 				continue;
    259 
    260 			if (ifindex && ifam->ifam_index != ifindex)
    261 				continue;
    262 
    263 			/* found */
    264 			*lenp = ifam->ifam_msglen;
    265 			return (char *)rtm;
    266 			/* NOTREACHED */
    267 #ifdef RTM_IFANNOUNCE
    268 		case RTM_IFANNOUNCE:
    269 #endif
    270 		case RTM_IFINFO:
    271 			/* found */
    272 			*lenp = rtm->rtm_msglen;
    273 			return (char *)rtm;
    274 			/* NOTREACHED */
    275 		}
    276 	}
    277 
    278 	return (char *)rtm;
    279 }
    280 #undef FILTER_MATCH
    281 
    282 struct in6_addr *
    283 get_addr(char *buf)
    284 {
    285 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    286 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    287 
    288 	sa = (struct sockaddr *)(rtm + 1);
    289 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    290 
    291 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    292 }
    293 
    294 int
    295 get_rtm_ifindex(char *buf)
    296 {
    297 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    298 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    299 
    300 	sa = (struct sockaddr *)(rtm + 1);
    301 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    302 
    303 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    304 }
    305 
    306 int
    307 get_ifm_ifindex(char *buf)
    308 {
    309 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    310 
    311 	return ((int)ifm->ifm_index);
    312 }
    313 
    314 int
    315 get_ifam_ifindex(char *buf)
    316 {
    317 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    318 
    319 	return ((int)ifam->ifam_index);
    320 }
    321 
    322 int
    323 get_ifm_flags(char *buf)
    324 {
    325 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    326 
    327 	return (ifm->ifm_flags);
    328 }
    329 
    330 #ifdef RTM_IFANNOUNCE
    331 int
    332 get_ifan_ifindex(char *buf)
    333 {
    334 	struct if_announcemsghdr *ifan = (struct if_announcemsghdr *)buf;
    335 
    336 	return ((int)ifan->ifan_index);
    337 }
    338 
    339 int
    340 get_ifan_what(char *buf)
    341 {
    342 	struct if_announcemsghdr *ifan = (struct if_announcemsghdr *)buf;
    343 
    344 	return ((int)ifan->ifan_what);
    345 }
    346 #endif
    347 
    348 int
    349 get_prefixlen(char *buf)
    350 {
    351 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    352 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    353 	unsigned char *p, *lim;
    354 
    355 	sa = (struct sockaddr *)(rtm + 1);
    356 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    357 	sa = rti_info[RTAX_NETMASK];
    358 
    359 	p = (unsigned char *)(&SIN6(sa)->sin6_addr);
    360 	lim = (unsigned char *)sa + sa->sa_len;
    361 	return prefixlen(p, lim);
    362 }
    363 
    364 int
    365 prefixlen(const unsigned char *p, const unsigned char *lim)
    366 {
    367 	int masklen;
    368 
    369 	for (masklen = 0; p < lim; p++) {
    370 		switch (*p) {
    371 		case 0xff:
    372 			masklen += 8;
    373 			break;
    374 		case 0xfe:
    375 			masklen += 7;
    376 			break;
    377 		case 0xfc:
    378 			masklen += 6;
    379 			break;
    380 		case 0xf8:
    381 			masklen += 5;
    382 			break;
    383 		case 0xf0:
    384 			masklen += 4;
    385 			break;
    386 		case 0xe0:
    387 			masklen += 3;
    388 			break;
    389 		case 0xc0:
    390 			masklen += 2;
    391 			break;
    392 		case 0x80:
    393 			masklen += 1;
    394 			break;
    395 		case 0x00:
    396 			break;
    397 		default:
    398 			return(-1);
    399 		}
    400 	}
    401 
    402 	return(masklen);
    403 }
    404 
    405 int
    406 rtmsg_type(char *buf)
    407 {
    408 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    409 
    410 	return(rtm->rtm_type);
    411 }
    412 
    413 int
    414 rtmsg_len(char *buf)
    415 {
    416 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    417 
    418 	return(rtm->rtm_msglen);
    419 }
    420