Home | History | Annotate | Line # | Download | only in rtadvd
if.c revision 1.27 
      1 /*	$NetBSD: if.c,v 1.27 2021/03/22 18:41:11 christos 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 #define RTM_NAMES
     34 #include <sys/param.h>
     35 #include <sys/queue.h>
     36 #include <sys/socket.h>
     37 #include <sys/sysctl.h>
     38 #include <sys/ioctl.h>
     39 #include <net/if.h>
     40 #include <net/if_types.h>
     41 #include <ifaddrs.h>
     42 #ifdef __FreeBSD__
     43 #include <net/ethernet.h>
     44 #else
     45 #include <net/if_ether.h>
     46 #endif
     47 #include <net/route.h>
     48 #include <net/if_dl.h>
     49 #include <netinet/in.h>
     50 #include <netinet/icmp6.h>
     51 #include <unistd.h>
     52 #include <errno.h>
     53 #include <stdlib.h>
     54 #include <string.h>
     55 #include <syslog.h>
     56 
     57 #include "rtadvd.h"
     58 #include "if.h"
     59 #include "logit.h"
     60 #include "prog_ops.h"
     61 
     62 #ifndef RT_ROUNDUP
     63 #define RT_ROUNDUP(a)							       \
     64 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
     65 #define RT_ADVANCE(x, n) (x += RT_ROUNDUP((n)->sa_len))
     66 #endif
     67 
     68 static void
     69 get_rtaddrs(int addrs, const struct sockaddr *sa,
     70     const struct sockaddr **rti_info)
     71 {
     72 	int i;
     73 
     74 	for (i = 0; i < RTAX_MAX; i++) {
     75 		if (addrs & (1 << i)) {
     76 			rti_info[i] = sa;
     77 			RT_ADVANCE(sa, sa);
     78 		}
     79 		else
     80 			rti_info[i] = NULL;
     81 	}
     82 }
     83 
     84 struct sockaddr_dl *
     85 if_nametosdl(const char *name)
     86 {
     87 	struct ifaddrs *ifap, *ifa;
     88 	struct sockaddr_dl *sdl;
     89 
     90 	if (getifaddrs(&ifap) != 0)
     91 		return (NULL);
     92 
     93 	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
     94 		if (strcmp(ifa->ifa_name, name) != 0)
     95 			continue;
     96 		if (ifa->ifa_addr->sa_family != AF_LINK)
     97 			continue;
     98 
     99 		sdl = malloc(ifa->ifa_addr->sa_len);
    100 		if (!sdl)
    101 			continue;	/*XXX*/
    102 
    103 		memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
    104 		freeifaddrs(ifap);
    105 		return (sdl);
    106 	}
    107 
    108 	freeifaddrs(ifap);
    109 	return (NULL);
    110 }
    111 
    112 int
    113 if_getmtu(const char *name)
    114 {
    115 	struct ifreq ifr;
    116 	int s, mtu;
    117 
    118 	if ((s = prog_socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
    119 		return 0;
    120 
    121 	memset(&ifr, 0, sizeof(ifr));
    122 	ifr.ifr_addr.sa_family = AF_INET6;
    123 	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
    124 	if (prog_ioctl(s, SIOCGIFMTU, &ifr) != -1)
    125 		mtu = ifr.ifr_mtu;
    126 	else
    127 		mtu = 0;
    128 	prog_close(s);
    129 
    130 	return mtu;
    131 }
    132 
    133 /* give interface index and its old flags, then new flags returned */
    134 int
    135 if_getflags(int ifindex, int oifflags)
    136 {
    137 	struct ifreq ifr;
    138 	int s;
    139 
    140 	if ((s = prog_socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    141 		logit(LOG_ERR, "<%s> socket: %m", __func__);
    142 		return (oifflags & ~IFF_UP);
    143 	}
    144 
    145 	memset(&ifr, 0, sizeof(ifr));
    146 	if_indextoname(ifindex, ifr.ifr_name);
    147 	if (prog_ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
    148 		logit(LOG_ERR, "<%s> ioctl:SIOCGIFFLAGS: failed for %s",
    149 		       __func__, ifr.ifr_name);
    150 		prog_close(s);
    151 		return (oifflags & ~IFF_UP);
    152 	}
    153 	prog_close(s);
    154 	return (ifr.ifr_flags);
    155 }
    156 
    157 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
    158 int
    159 lladdropt_length(struct sockaddr_dl *sdl)
    160 {
    161 	switch (sdl->sdl_type) {
    162 	case IFT_ETHER:
    163 	case IFT_FDDI:
    164 		return(ROUNDUP8(ETHER_ADDR_LEN + 2));
    165 	default:
    166 		return(0);
    167 	}
    168 }
    169 
    170 void
    171 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
    172 {
    173 	char *addr;
    174 
    175 	ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
    176 
    177 	switch (sdl->sdl_type) {
    178 	case IFT_ETHER:
    179 	case IFT_FDDI:
    180 		ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
    181 		addr = (char *)(ndopt + 1);
    182 		memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
    183 		break;
    184 	default:
    185 		logit(LOG_ERR, "<%s> unsupported link type(%d)",
    186 		    __func__, sdl->sdl_type);
    187 		exit(1);
    188 	}
    189 
    190 	return;
    191 }
    192 
    193 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
    194 #define SIN6(s) ((const struct sockaddr_in6 *)(s))
    195 #define SDL(s) ((const struct sockaddr_dl *)(s))
    196 char *
    197 get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
    198 {
    199 	struct rt_msghdr *rtm;
    200 	struct ifa_msghdr *ifam;
    201 	const struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
    202 
    203 	*lenp = 0;
    204 	for (rtm = (struct rt_msghdr *)buf;
    205 	     rtm < (struct rt_msghdr *)lim;
    206 	     rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
    207 		/* just for safety */
    208 		if (!rtm->rtm_msglen) {
    209 			logit(LOG_WARNING, "<%s> rtm_msglen is 0 "
    210 				"(buf=%p lim=%p rtm=%p)", __func__,
    211 				buf, lim, rtm);
    212 			break;
    213 		}
    214 		if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
    215 			continue;
    216 		}
    217 
    218 		switch (rtm->rtm_type) {
    219 		case RTM_GET:
    220 		case RTM_ADD:
    221 		case RTM_DELETE:
    222 			/* address related checks */
    223 			sa = (struct sockaddr *)(rtm + 1);
    224 			get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    225 			if ((dst = rti_info[RTAX_DST]) == NULL ||
    226 			    dst->sa_family != AF_INET6)
    227 				continue;
    228 
    229 			if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
    230 			    IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
    231 				continue;
    232 
    233 			if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
    234 			    gw->sa_family != AF_LINK)
    235 				continue;
    236 			if (ifindex && SDL(gw)->sdl_index != ifindex)
    237 				continue;
    238 
    239 			if (rti_info[RTAX_NETMASK] == NULL)
    240 				continue;
    241 
    242 			/* found */
    243 			*lenp = rtm->rtm_msglen;
    244 			return (char *)rtm;
    245 			/* NOTREACHED */
    246 		case RTM_NEWADDR:
    247 		case RTM_DELADDR:
    248 			ifam = (struct ifa_msghdr *)rtm;
    249 
    250 			/* address related checks */
    251 			sa = (struct sockaddr *)(ifam + 1);
    252 			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
    253 			if ((ifa = rti_info[RTAX_IFA]) == NULL ||
    254 			    (ifa->sa_family != AF_INET &&
    255 			     ifa->sa_family != AF_INET6))
    256 				continue;
    257 
    258 			if (ifa->sa_family == AF_INET6 &&
    259 			    (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
    260 			     IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
    261 				continue;
    262 
    263 			if (ifindex && ifam->ifam_index != ifindex)
    264 				continue;
    265 
    266 			/* found */
    267 			*lenp = ifam->ifam_msglen;
    268 			return (char *)rtm;
    269 			/* NOTREACHED */
    270 #ifdef RTM_IFANNOUNCE
    271 		case RTM_IFANNOUNCE:
    272 #endif
    273 		case RTM_IFINFO:
    274 			/* found */
    275 			*lenp = rtm->rtm_msglen;
    276 			return (char *)rtm;
    277 			/* NOTREACHED */
    278 		}
    279 	}
    280 
    281 	return (char *)rtm;
    282 }
    283 #undef FILTER_MATCH
    284 
    285 const struct in6_addr *
    286 get_addr(const void *buf)
    287 {
    288 	const struct rt_msghdr *rtm = buf;
    289 	const struct sockaddr *sa, *rti_info[RTAX_MAX];
    290 
    291 	sa = (const struct sockaddr *)(rtm + 1);
    292 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    293 
    294 	return &SIN6(rti_info[RTAX_DST])->sin6_addr;
    295 }
    296 
    297 int
    298 get_rtm_ifindex(const void *buf)
    299 {
    300 	const struct rt_msghdr *rtm = buf;
    301 	const struct sockaddr *sa, *rti_info[RTAX_MAX];
    302 
    303 	sa = (const struct sockaddr *)(rtm + 1);
    304 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    305 
    306 	return SDL(rti_info[RTAX_GATEWAY])->sdl_index;
    307 }
    308 
    309 int
    310 get_ifm_ifindex(const void *buf)
    311 {
    312 	const struct if_msghdr *ifm = buf;
    313 
    314 	return (int)ifm->ifm_index;
    315 }
    316 
    317 int
    318 get_ifam_ifindex(const void *buf)
    319 {
    320 	const struct ifa_msghdr *ifam = buf;
    321 
    322 	return (int)ifam->ifam_index;
    323 }
    324 
    325 int
    326 get_ifm_flags(const void *buf)
    327 {
    328 	const struct if_msghdr *ifm = buf;
    329 
    330 	return ifm->ifm_flags;
    331 }
    332 
    333 #ifdef RTM_IFANNOUNCE
    334 int
    335 get_ifan_ifindex(const void *buf)
    336 {
    337 	const struct if_announcemsghdr *ifan = buf;
    338 
    339 	return (int)ifan->ifan_index;
    340 }
    341 
    342 int
    343 get_ifan_what(const void *buf)
    344 {
    345 	const struct if_announcemsghdr *ifan = buf;
    346 
    347 	return (int)ifan->ifan_what;
    348 }
    349 #endif
    350 
    351 int
    352 get_prefixlen(const void *buf)
    353 {
    354 	const struct rt_msghdr *rtm = buf;
    355 	const struct sockaddr *sa, *rti_info[RTAX_MAX];
    356 	const unsigned char *p, *lim;
    357 
    358 	sa = (const struct sockaddr *)(rtm + 1);
    359 	get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
    360 	sa = rti_info[RTAX_NETMASK];
    361 
    362 	p = (const unsigned char *)(&SIN6(sa)->sin6_addr);
    363 	lim = (const unsigned char *)sa + sa->sa_len;
    364 	return prefixlen(p, lim);
    365 }
    366 
    367 int
    368 prefixlen(const unsigned char *p, const unsigned char *lim)
    369 {
    370 	int masklen;
    371 
    372 	for (masklen = 0; p < lim; p++) {
    373 		switch (*p) {
    374 		case 0xff:
    375 			masklen += 8;
    376 			break;
    377 		case 0xfe:
    378 			masklen += 7;
    379 			break;
    380 		case 0xfc:
    381 			masklen += 6;
    382 			break;
    383 		case 0xf8:
    384 			masklen += 5;
    385 			break;
    386 		case 0xf0:
    387 			masklen += 4;
    388 			break;
    389 		case 0xe0:
    390 			masklen += 3;
    391 			break;
    392 		case 0xc0:
    393 			masklen += 2;
    394 			break;
    395 		case 0x80:
    396 			masklen += 1;
    397 			break;
    398 		case 0x00:
    399 			break;
    400 		default:
    401 			return -1;
    402 		}
    403 	}
    404 
    405 	return masklen;
    406 }
    407 
    408 int
    409 rtmsg_type(const void *buf)
    410 {
    411 	const struct rt_msghdr *rtm = buf;
    412 
    413 	return rtm->rtm_type;
    414 }
    415 
    416 const char *
    417 rtmsg_typestr(const void *buf)
    418 {
    419 	const struct rt_msghdr *rtm = buf;
    420 
    421 	return rtm->rtm_type < __arraycount(rtm_names)
    422 	    ? rtm_names[rtm->rtm_type] : "*unknown*";
    423 }
    424 
    425 int
    426 rtmsg_len(const void *buf)
    427 {
    428 	const struct rt_msghdr *rtm = buf;
    429 
    430 	return rtm->rtm_msglen;
    431 }
    432