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getifaddrs.c revision 1.11.16.1 
      1 /*	$NetBSD: getifaddrs.c,v 1.11.16.1 2009/05/13 19:18:25 jym 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 1.11.16.1 2009/05/13 19:18:25 jym Exp $");
     31 #endif /* LIBC_SCCS and not lint */
     32 
     33 #include "namespace.h"
     34 #include <sys/types.h>
     35 #include <sys/ioctl.h>
     36 #include <sys/socket.h>
     37 #include <net/if.h>
     38 #include <sys/param.h>
     39 #include <net/route.h>
     40 #include <sys/sysctl.h>
     41 #include <net/if_dl.h>
     42 
     43 #include <assert.h>
     44 #include <errno.h>
     45 #include <ifaddrs.h>
     46 #include <stdlib.h>
     47 #include <string.h>
     48 
     49 #ifdef __weak_alias
     50 __weak_alias(getifaddrs,_getifaddrs)
     51 __weak_alias(freeifaddrs,_freeifaddrs)
     52 #endif
     53 
     54 #define	SALIGN	(sizeof(long) - 1)
     55 #define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
     56 
     57 int
     58 getifaddrs(struct ifaddrs **pif)
     59 {
     60 	int icnt = 1;
     61 	int dcnt = 0;
     62 	int ncnt = 0;
     63 	int mib[6];
     64 	size_t needed;
     65 	char *buf;
     66 	char *next;
     67 	struct ifaddrs cif;
     68 	char *p, *p0;
     69 	struct rt_msghdr *rtm;
     70 	struct if_msghdr *ifm;
     71 	struct ifa_msghdr *ifam;
     72 	struct sockaddr *sa;
     73 	struct ifaddrs *ifa, *ift;
     74 	u_short idx = 0;
     75 	int i;
     76 	size_t len, alen;
     77 	char *data;
     78 	char *names;
     79 
     80 	_DIAGASSERT(pif != NULL);
     81 
     82 	mib[0] = CTL_NET;
     83 	mib[1] = PF_ROUTE;
     84 	mib[2] = 0;             /* protocol */
     85 	mib[3] = 0;             /* wildcard address family */
     86 	mib[4] = NET_RT_IFLIST;
     87 	mib[5] = 0;             /* no flags */
     88 	if (sysctl(mib, __arraycount(mib), NULL, &needed, NULL, 0) < 0)
     89 		return (-1);
     90 	if ((buf = malloc(needed)) == NULL)
     91 		return (-1);
     92 	if (sysctl(mib, __arraycount(mib), buf, &needed, NULL, 0) < 0) {
     93 		free(buf);
     94 		return (-1);
     95 	}
     96 
     97 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
     98 		rtm = (struct rt_msghdr *)(void *)next;
     99 		if (rtm->rtm_version != RTM_VERSION)
    100 			continue;
    101 		switch (rtm->rtm_type) {
    102 		case RTM_IFINFO:
    103 			ifm = (struct if_msghdr *)(void *)rtm;
    104 			if (ifm->ifm_addrs & RTA_IFP) {
    105 				const struct sockaddr_dl *dl;
    106 
    107 				idx = ifm->ifm_index;
    108 				++icnt;
    109 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    110 				dcnt += SA_RLEN((const struct sockaddr *)(const void *)dl) +
    111 				    ALIGNBYTES;
    112 				dcnt += sizeof(ifm->ifm_data);
    113 				ncnt += dl->sdl_nlen + 1;
    114 			} else
    115 				idx = 0;
    116 			break;
    117 
    118 		case RTM_NEWADDR:
    119 			ifam = (struct ifa_msghdr *)(void *)rtm;
    120 			if (idx && ifam->ifam_index != idx)
    121 				abort();	/* this cannot happen */
    122 
    123 #define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
    124 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    125 				break;
    126 			p = (char *)(void *)(ifam + 1);
    127 			++icnt;
    128 			/* Scan to look for length of address */
    129 			alen = 0;
    130 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    131 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    132 				    == 0)
    133 					continue;
    134 				sa = (struct sockaddr *)(void *)p;
    135 				len = SA_RLEN(sa);
    136 				if (i == RTAX_IFA) {
    137 					alen = len;
    138 					break;
    139 				}
    140 				p += len;
    141 			}
    142 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    143 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    144 				    == 0)
    145 					continue;
    146 				sa = (struct sockaddr *)(void *)p;
    147 				len = SA_RLEN(sa);
    148 				if (i == RTAX_NETMASK && sa->sa_len == 0)
    149 					dcnt += alen;
    150 				else
    151 					dcnt += len;
    152 				p += len;
    153 			}
    154 			break;
    155 		}
    156 	}
    157 
    158 	if (icnt + dcnt + ncnt == 1) {
    159 		*pif = NULL;
    160 		free(buf);
    161 		return (0);
    162 	}
    163 	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
    164 	if (data == NULL) {
    165 		free(buf);
    166 		return(-1);
    167 	}
    168 
    169 	ifa = (struct ifaddrs *)(void *)data;
    170 	data += sizeof(struct ifaddrs) * icnt;
    171 	names = data + dcnt;
    172 
    173 	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
    174 	ift = ifa;
    175 
    176 	idx = 0;
    177 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    178 		rtm = (struct rt_msghdr *)(void *)next;
    179 		if (rtm->rtm_version != RTM_VERSION)
    180 			continue;
    181 		switch (rtm->rtm_type) {
    182 		case RTM_IFINFO:
    183 			ifm = (struct if_msghdr *)(void *)rtm;
    184 			if (ifm->ifm_addrs & RTA_IFP) {
    185 				const struct sockaddr_dl *dl;
    186 
    187 				idx = ifm->ifm_index;
    188 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    189 
    190 				memset(&cif, 0, sizeof(cif));
    191 
    192 				cif.ifa_name = names;
    193 				cif.ifa_flags = (int)ifm->ifm_flags;
    194 				memcpy(names, dl->sdl_data,
    195 				    (size_t)dl->sdl_nlen);
    196 				names[dl->sdl_nlen] = 0;
    197 				names += dl->sdl_nlen + 1;
    198 
    199 				cif.ifa_addr = (struct sockaddr *)(void *)data;
    200 				memcpy(data, dl, (size_t)dl->sdl_len);
    201 				data += SA_RLEN((const struct sockaddr *)(const void *)dl);
    202 
    203 				/* ifm_data needs to be aligned */
    204 				cif.ifa_data = data = (void *)ALIGN(data);
    205 				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
    206  				data += sizeof(ifm->ifm_data);
    207 			} else
    208 				idx = 0;
    209 			break;
    210 
    211 		case RTM_NEWADDR:
    212 			ifam = (struct ifa_msghdr *)(void *)rtm;
    213 			if (idx && ifam->ifam_index != idx)
    214 				abort();	/* this cannot happen */
    215 
    216 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    217 				break;
    218 			ift->ifa_name = cif.ifa_name;
    219 			ift->ifa_flags = cif.ifa_flags;
    220 			ift->ifa_data = NULL;
    221 			p = (char *)(void *)(ifam + 1);
    222 			/* Scan to look for length of address */
    223 			alen = 0;
    224 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    225 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    226 				    == 0)
    227 					continue;
    228 				sa = (struct sockaddr *)(void *)p;
    229 				len = SA_RLEN(sa);
    230 				if (i == RTAX_IFA) {
    231 					alen = len;
    232 					break;
    233 				}
    234 				p += len;
    235 			}
    236 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    237 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    238 				    == 0)
    239 					continue;
    240 				sa = (struct sockaddr *)(void *)p;
    241 				len = SA_RLEN(sa);
    242 				switch (i) {
    243 				case RTAX_IFA:
    244 					ift->ifa_addr =
    245 					    (struct sockaddr *)(void *)data;
    246 					memcpy(data, p, len);
    247 					data += len;
    248 					if (ift->ifa_addr->sa_family == AF_LINK)
    249 						ift->ifa_data = cif.ifa_data;
    250 					break;
    251 
    252 				case RTAX_NETMASK:
    253 					ift->ifa_netmask =
    254 					    (struct sockaddr *)(void *)data;
    255 					if (sa->sa_len == 0) {
    256 						memset(data, 0, alen);
    257 						data += alen;
    258 						break;
    259 					}
    260 					memcpy(data, p, len);
    261 					data += len;
    262 					break;
    263 
    264 				case RTAX_BRD:
    265 					ift->ifa_broadaddr =
    266 					    (struct sockaddr *)(void *)data;
    267 					memcpy(data, p, len);
    268 					data += len;
    269 					break;
    270 				}
    271 				p += len;
    272 			}
    273 
    274 
    275 			ift = (ift->ifa_next = ift + 1);
    276 			break;
    277 		}
    278 	}
    279 
    280 	free(buf);
    281 	if (--ift >= ifa) {
    282 		ift->ifa_next = NULL;
    283 		*pif = ifa;
    284 	} else {
    285 		*pif = NULL;
    286 		free(ifa);
    287 	}
    288 	return (0);
    289 }
    290 
    291 void
    292 freeifaddrs(struct ifaddrs *ifp)
    293 {
    294 
    295 	_DIAGASSERT(ifp != NULL);
    296 
    297 	free(ifp);
    298 }
    299