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if.c revision 1.23 
      1 /*	$NetBSD: if.c,v 1.23 2015/06/05 15:41:59 roy 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: %m", __func__);
    138 		return (oifflags & ~IFF_UP);
    139 	}
    140 
    141 	memset(&ifr, 0, sizeof(ifr));
    142 	if_indextoname(ifindex, ifr.ifr_name);
    143 	if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
    144 		syslog(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    145 		       __func__, ifr.ifr_name);
    146 		close(s);
    147 		return (oifflags & ~IFF_UP);
    148 	}
    149 	close(s);
    150 	return (ifr.ifr_flags);
    151 }
    152 
    153 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    154 int
    155 lladdropt_length(struct sockaddr_dl *sdl)
    156 {
    157 	switch (sdl->sdl_type) {
    158 	case IFT_ETHER:
    159 	case IFT_FDDI:
    160 		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    161 	default:
    162 		return(0);
    163 	}
    164 }
    165 
    166 void
    167 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    168 {
    169 	char *addr;
    170 
    171 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    172 
    173 	switch (sdl->sdl_type) {
    174 	case IFT_ETHER:
    175 	case IFT_FDDI:
    176 		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    177 		addr = (char *)(ndopt + 1);
    178 		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    179 		break;
    180 	default:
    181 		syslog(LOG_ERR, "<%s> unsupported link type(%d)",
    182 		    __func__, sdl->sdl_type);
    183 		exit(1);
    184 	}
    185 
    186 	return;
    187 }
    188 
    189 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    190 #define SIN6(s) ((struct sockaddr_in6 *)(s))
    191 #define SDL(s) ((struct sockaddr_dl *)(s))
    192 char *
    193 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    194 {
    195 	struct rt_msghdr *rtm;
    196 	struct ifa_msghdr *ifam;
    197 	struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    198 
    199 	*lenp = 0;
    200 	for (rtm = (struct rt_msghdr *)buf;
    201 	     rtm < (struct rt_msghdr *)lim;
    202 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    203 		/* just for safety */
    204 		if (!rtm->rtm_msglen) {
    205 			syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
    206 				"(buf=%p lim=%p rtm=%p)", __func__,
    207 				buf, lim, rtm);
    208 			break;
    209 		}
    210 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    211 			continue;
    212 		}
    213 
    214 		switch (rtm->rtm_type) {
    215 		case RTM_GET:
    216 		case RTM_ADD:
    217 		case RTM_DELETE:
    218 			/* address related checks */
    219 			sa = (struct sockaddr *)(rtm + 1);
    220 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    221 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    222 			    dst->sa_family != AF_INET6)
    223 				continue;
    224 
    225 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    226 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    227 				continue;
    228 
    229 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    230 			    gw->sa_family != AF_LINK)
    231 				continue;
    232 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    233 				continue;
    234 
    235 			if (rti_info[RTAX_NETMASK] == NULL)
    236 				continue;
    237 
    238 			/* found */
    239 			*lenp = rtm->rtm_msglen;
    240 			return (char *)rtm;
    241 			/* NOTREACHED */
    242 		case RTM_NEWADDR:
    243 		case RTM_DELADDR:
    244 			ifam = (struct ifa_msghdr *)rtm;
    245 
    246 			/* address related checks */
    247 			sa = (struct sockaddr *)(ifam + 1);
    248 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    249 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    250 			    (ifa->sa_family != AF_INET &&
    251 			     ifa->sa_family != AF_INET6))
    252 				continue;
    253 
    254 			if (ifa->sa_family == AF_INET6 &&
    255 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    256 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    257 				continue;
    258 
    259 			if (ifindex && ifam->ifam_index != ifindex)
    260 				continue;
    261 
    262 			/* found */
    263 			*lenp = ifam->ifam_msglen;
    264 			return (char *)rtm;
    265 			/* NOTREACHED */
    266 #ifdef RTM_IFANNOUNCE
    267 		case RTM_IFANNOUNCE:
    268 #endif
    269 		case RTM_IFINFO:
    270 			/* found */
    271 			*lenp = rtm->rtm_msglen;
    272 			return (char *)rtm;
    273 			/* NOTREACHED */
    274 		}
    275 	}
    276 
    277 	return (char *)rtm;
    278 }
    279 #undef FILTER_MATCH
    280 
    281 struct in6_addr *
    282 get_addr(char *buf)
    283 {
    284 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    285 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    286 
    287 	sa = (struct sockaddr *)(rtm + 1);
    288 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    289 
    290 	return(&SIN6(rti_info[RTAX_DST])->sin6_addr);
    291 }
    292 
    293 int
    294 get_rtm_ifindex(char *buf)
    295 {
    296 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    297 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    298 
    299 	sa = (struct sockaddr *)(rtm + 1);
    300 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    301 
    302 	return(((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
    303 }
    304 
    305 int
    306 get_ifm_ifindex(char *buf)
    307 {
    308 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    309 
    310 	return ((int)ifm->ifm_index);
    311 }
    312 
    313 int
    314 get_ifam_ifindex(char *buf)
    315 {
    316 	struct ifa_msghdr *ifam = (struct ifa_msghdr *)buf;
    317 
    318 	return ((int)ifam->ifam_index);
    319 }
    320 
    321 int
    322 get_ifm_flags(char *buf)
    323 {
    324 	struct if_msghdr *ifm = (struct if_msghdr *)buf;
    325 
    326 	return (ifm->ifm_flags);
    327 }
    328 
    329 #ifdef RTM_IFANNOUNCE
    330 int
    331 get_ifan_ifindex(char *buf)
    332 {
    333 	struct if_announcemsghdr *ifan = (struct if_announcemsghdr *)buf;
    334 
    335 	return ((int)ifan->ifan_index);
    336 }
    337 
    338 int
    339 get_ifan_what(char *buf)
    340 {
    341 	struct if_announcemsghdr *ifan = (struct if_announcemsghdr *)buf;
    342 
    343 	return ((int)ifan->ifan_what);
    344 }
    345 #endif
    346 
    347 int
    348 get_prefixlen(char *buf)
    349 {
    350 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    351 	struct sockaddr *sa, *rti_info[RTAX_MAX];
    352 	unsigned char *p, *lim;
    353 
    354 	sa = (struct sockaddr *)(rtm + 1);
    355 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    356 	sa = rti_info[RTAX_NETMASK];
    357 
    358 	p = (unsigned char *)(&SIN6(sa)->sin6_addr);
    359 	lim = (unsigned char *)sa + sa->sa_len;
    360 	return prefixlen(p, lim);
    361 }
    362 
    363 int
    364 prefixlen(const unsigned char *p, const unsigned char *lim)
    365 {
    366 	int masklen;
    367 
    368 	for (masklen = 0; p < lim; p++) {
    369 		switch (*p) {
    370 		case 0xff:
    371 			masklen += 8;
    372 			break;
    373 		case 0xfe:
    374 			masklen += 7;
    375 			break;
    376 		case 0xfc:
    377 			masklen += 6;
    378 			break;
    379 		case 0xf8:
    380 			masklen += 5;
    381 			break;
    382 		case 0xf0:
    383 			masklen += 4;
    384 			break;
    385 		case 0xe0:
    386 			masklen += 3;
    387 			break;
    388 		case 0xc0:
    389 			masklen += 2;
    390 			break;
    391 		case 0x80:
    392 			masklen += 1;
    393 			break;
    394 		case 0x00:
    395 			break;
    396 		default:
    397 			return(-1);
    398 		}
    399 	}
    400 
    401 	return(masklen);
    402 }
    403 
    404 int
    405 rtmsg_type(char *buf)
    406 {
    407 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    408 
    409 	return(rtm->rtm_type);
    410 }
    411 
    412 int
    413 rtmsg_len(char *buf)
    414 {
    415 	struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
    416 
    417 	return(rtm->rtm_msglen);
    418 }
    419