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getifaddrs.c revision 1.14 
      1 /*	$NetBSD: getifaddrs.c,v 1.14 2011/02/04 02:01:12 matt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995, 1999
      5  *	Berkeley Software Design, Inc.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
     14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     16  * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
     17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     23  * SUCH DAMAGE.
     24  *
     25  *	BSDI getifaddrs.c,v 2.12 2000/02/23 14:51:59 dab Exp
     26  */
     27 
     28 #include <sys/cdefs.h>
     29 #if defined(LIBC_SCCS) && !defined(lint)
     30 __RCSID("$NetBSD: getifaddrs.c,v 1.14 2011/02/04 02:01:12 matt Exp $");
     31 #endif /* LIBC_SCCS and not lint */
     32 
     33 #ifndef RUMP_ACTION
     34 #include "namespace.h"
     35 #endif
     36 #include <sys/types.h>
     37 #include <sys/ioctl.h>
     38 #include <sys/socket.h>
     39 #include <net/if.h>
     40 #include <sys/param.h>
     41 #include <net/route.h>
     42 #include <sys/sysctl.h>
     43 #include <net/if_dl.h>
     44 
     45 #include <assert.h>
     46 #include <errno.h>
     47 #include <ifaddrs.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 
     51 #if defined(__weak_alias) && !defined(RUMP_ACTION)
     52 __weak_alias(getifaddrs,_getifaddrs)
     53 __weak_alias(freeifaddrs,_freeifaddrs)
     54 #endif
     55 
     56 #ifdef RUMP_ACTION
     57 #include <rump/rump_syscalls.h>
     58 #define sysctl(a,b,c,d,e,f) rump_sys___sysctl(a,b,c,d,e,f)
     59 #endif
     60 
     61 #define	SA_RLEN(sa)	RT_ROUNDUP((sa)->sa_len)
     62 
     63 int
     64 getifaddrs(struct ifaddrs **pif)
     65 {
     66 	int icnt = 1;
     67 	int dcnt = 0;
     68 	int ncnt = 0;
     69 	int mib[6];
     70 	size_t needed;
     71 	char *buf;
     72 	char *next;
     73 	struct ifaddrs cif;
     74 	char *p, *p0;
     75 	struct rt_msghdr *rtm;
     76 	struct if_msghdr *ifm;
     77 	struct ifa_msghdr *ifam;
     78 	struct sockaddr *sa;
     79 	struct ifaddrs *ifa, *ift;
     80 	u_short idx = 0;
     81 	int i;
     82 	size_t len, alen;
     83 	char *data;
     84 	char *names;
     85 
     86 	_DIAGASSERT(pif != NULL);
     87 
     88 	mib[0] = CTL_NET;
     89 	mib[1] = PF_ROUTE;
     90 	mib[2] = 0;             /* protocol */
     91 	mib[3] = 0;             /* wildcard address family */
     92 	mib[4] = NET_RT_IFLIST;
     93 	mib[5] = 0;             /* no flags */
     94 	if (sysctl(mib, __arraycount(mib), NULL, &needed, NULL, 0) < 0)
     95 		return (-1);
     96 	if ((buf = malloc(needed)) == NULL)
     97 		return (-1);
     98 	if (sysctl(mib, __arraycount(mib), buf, &needed, NULL, 0) < 0) {
     99 		free(buf);
    100 		return (-1);
    101 	}
    102 
    103 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    104 		rtm = (struct rt_msghdr *)(void *)next;
    105 		if (rtm->rtm_version != RTM_VERSION)
    106 			continue;
    107 		switch (rtm->rtm_type) {
    108 		case RTM_IFINFO:
    109 			ifm = (struct if_msghdr *)(void *)rtm;
    110 			if (ifm->ifm_addrs & RTA_IFP) {
    111 				const struct sockaddr_dl *dl;
    112 
    113 				idx = ifm->ifm_index;
    114 				++icnt;
    115 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    116 				dcnt += SA_RLEN((const struct sockaddr *)(const void *)dl) +
    117 				    ALIGNBYTES;
    118 				dcnt += sizeof(ifm->ifm_data);
    119 				ncnt += dl->sdl_nlen + 1;
    120 			} else
    121 				idx = 0;
    122 			break;
    123 
    124 		case RTM_NEWADDR:
    125 			ifam = (struct ifa_msghdr *)(void *)rtm;
    126 			if (idx && ifam->ifam_index != idx)
    127 				abort();	/* this cannot happen */
    128 
    129 #define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
    130 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    131 				break;
    132 			p = (char *)(void *)(ifam + 1);
    133 			++icnt;
    134 			/* Scan to look for length of address */
    135 			alen = 0;
    136 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    137 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    138 				    == 0)
    139 					continue;
    140 				sa = (struct sockaddr *)(void *)p;
    141 				len = SA_RLEN(sa);
    142 				if (i == RTAX_IFA) {
    143 					alen = len;
    144 					break;
    145 				}
    146 				p += len;
    147 			}
    148 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    149 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    150 				    == 0)
    151 					continue;
    152 				sa = (struct sockaddr *)(void *)p;
    153 				len = SA_RLEN(sa);
    154 				if (i == RTAX_NETMASK && sa->sa_len == 0)
    155 					dcnt += alen;
    156 				else
    157 					dcnt += len;
    158 				p += len;
    159 			}
    160 			break;
    161 		}
    162 	}
    163 
    164 	if (icnt + dcnt + ncnt == 1) {
    165 		*pif = NULL;
    166 		free(buf);
    167 		return (0);
    168 	}
    169 	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
    170 	if (data == NULL) {
    171 		free(buf);
    172 		return(-1);
    173 	}
    174 
    175 	ifa = (struct ifaddrs *)(void *)data;
    176 	data += sizeof(struct ifaddrs) * icnt;
    177 	names = data + dcnt;
    178 
    179 	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
    180 	ift = ifa;
    181 
    182 	idx = 0;
    183 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    184 		rtm = (struct rt_msghdr *)(void *)next;
    185 		if (rtm->rtm_version != RTM_VERSION)
    186 			continue;
    187 		switch (rtm->rtm_type) {
    188 		case RTM_IFINFO:
    189 			ifm = (struct if_msghdr *)(void *)rtm;
    190 			if (ifm->ifm_addrs & RTA_IFP) {
    191 				const struct sockaddr_dl *dl;
    192 
    193 				idx = ifm->ifm_index;
    194 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    195 
    196 				memset(&cif, 0, sizeof(cif));
    197 
    198 				cif.ifa_name = names;
    199 				cif.ifa_flags = (int)ifm->ifm_flags;
    200 				memcpy(names, dl->sdl_data,
    201 				    (size_t)dl->sdl_nlen);
    202 				names[dl->sdl_nlen] = 0;
    203 				names += dl->sdl_nlen + 1;
    204 
    205 				cif.ifa_addr = (struct sockaddr *)(void *)data;
    206 				memcpy(data, dl, (size_t)dl->sdl_len);
    207 				data += SA_RLEN((const struct sockaddr *)(const void *)dl);
    208 
    209 				/* ifm_data needs to be aligned */
    210 				cif.ifa_data = data = (void *)ALIGN(data);
    211 				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
    212  				data += sizeof(ifm->ifm_data);
    213 			} else
    214 				idx = 0;
    215 			break;
    216 
    217 		case RTM_NEWADDR:
    218 			ifam = (struct ifa_msghdr *)(void *)rtm;
    219 			if (idx && ifam->ifam_index != idx)
    220 				abort();	/* this cannot happen */
    221 
    222 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    223 				break;
    224 			ift->ifa_name = cif.ifa_name;
    225 			ift->ifa_flags = cif.ifa_flags;
    226 			ift->ifa_data = NULL;
    227 			p = (char *)(void *)(ifam + 1);
    228 			/* Scan to look for length of address */
    229 			alen = 0;
    230 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    231 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    232 				    == 0)
    233 					continue;
    234 				sa = (struct sockaddr *)(void *)p;
    235 				len = SA_RLEN(sa);
    236 				if (i == RTAX_IFA) {
    237 					alen = len;
    238 					break;
    239 				}
    240 				p += len;
    241 			}
    242 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    243 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    244 				    == 0)
    245 					continue;
    246 				sa = (struct sockaddr *)(void *)p;
    247 				len = SA_RLEN(sa);
    248 				switch (i) {
    249 				case RTAX_IFA:
    250 					ift->ifa_addr =
    251 					    (struct sockaddr *)(void *)data;
    252 					memcpy(data, p, len);
    253 					data += len;
    254 					if (ift->ifa_addr->sa_family == AF_LINK)
    255 						ift->ifa_data = cif.ifa_data;
    256 					break;
    257 
    258 				case RTAX_NETMASK:
    259 					ift->ifa_netmask =
    260 					    (struct sockaddr *)(void *)data;
    261 					if (sa->sa_len == 0) {
    262 						memset(data, 0, alen);
    263 						data += alen;
    264 						break;
    265 					}
    266 					memcpy(data, p, len);
    267 					data += len;
    268 					break;
    269 
    270 				case RTAX_BRD:
    271 					ift->ifa_broadaddr =
    272 					    (struct sockaddr *)(void *)data;
    273 					memcpy(data, p, len);
    274 					data += len;
    275 					break;
    276 				}
    277 				p += len;
    278 			}
    279 
    280 
    281 			ift = (ift->ifa_next = ift + 1);
    282 			break;
    283 		}
    284 	}
    285 
    286 	free(buf);
    287 	if (--ift >= ifa) {
    288 		ift->ifa_next = NULL;
    289 		*pif = ifa;
    290 	} else {
    291 		*pif = NULL;
    292 		free(ifa);
    293 	}
    294 	return (0);
    295 }
    296 
    297 void
    298 freeifaddrs(struct ifaddrs *ifp)
    299 {
    300 
    301 	_DIAGASSERT(ifp != NULL);
    302 
    303 	free(ifp);
    304 }
    305