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getifaddrs.c revision 1.13 
      1 /*	$NetBSD: getifaddrs.c,v 1.13 2010/11/05 16:23:56 pooka 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 1.13 2010/11/05 16:23:56 pooka 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	SALIGN	(sizeof(long) - 1)
     62 #define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
     63 
     64 int
     65 getifaddrs(struct ifaddrs **pif)
     66 {
     67 	int icnt = 1;
     68 	int dcnt = 0;
     69 	int ncnt = 0;
     70 	int mib[6];
     71 	size_t needed;
     72 	char *buf;
     73 	char *next;
     74 	struct ifaddrs cif;
     75 	char *p, *p0;
     76 	struct rt_msghdr *rtm;
     77 	struct if_msghdr *ifm;
     78 	struct ifa_msghdr *ifam;
     79 	struct sockaddr *sa;
     80 	struct ifaddrs *ifa, *ift;
     81 	u_short idx = 0;
     82 	int i;
     83 	size_t len, alen;
     84 	char *data;
     85 	char *names;
     86 
     87 	_DIAGASSERT(pif != NULL);
     88 
     89 	mib[0] = CTL_NET;
     90 	mib[1] = PF_ROUTE;
     91 	mib[2] = 0;             /* protocol */
     92 	mib[3] = 0;             /* wildcard address family */
     93 	mib[4] = NET_RT_IFLIST;
     94 	mib[5] = 0;             /* no flags */
     95 	if (sysctl(mib, __arraycount(mib), NULL, &needed, NULL, 0) < 0)
     96 		return (-1);
     97 	if ((buf = malloc(needed)) == NULL)
     98 		return (-1);
     99 	if (sysctl(mib, __arraycount(mib), buf, &needed, NULL, 0) < 0) {
    100 		free(buf);
    101 		return (-1);
    102 	}
    103 
    104 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    105 		rtm = (struct rt_msghdr *)(void *)next;
    106 		if (rtm->rtm_version != RTM_VERSION)
    107 			continue;
    108 		switch (rtm->rtm_type) {
    109 		case RTM_IFINFO:
    110 			ifm = (struct if_msghdr *)(void *)rtm;
    111 			if (ifm->ifm_addrs & RTA_IFP) {
    112 				const struct sockaddr_dl *dl;
    113 
    114 				idx = ifm->ifm_index;
    115 				++icnt;
    116 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    117 				dcnt += SA_RLEN((const struct sockaddr *)(const void *)dl) +
    118 				    ALIGNBYTES;
    119 				dcnt += sizeof(ifm->ifm_data);
    120 				ncnt += dl->sdl_nlen + 1;
    121 			} else
    122 				idx = 0;
    123 			break;
    124 
    125 		case RTM_NEWADDR:
    126 			ifam = (struct ifa_msghdr *)(void *)rtm;
    127 			if (idx && ifam->ifam_index != idx)
    128 				abort();	/* this cannot happen */
    129 
    130 #define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
    131 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    132 				break;
    133 			p = (char *)(void *)(ifam + 1);
    134 			++icnt;
    135 			/* Scan to look for length of address */
    136 			alen = 0;
    137 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    138 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    139 				    == 0)
    140 					continue;
    141 				sa = (struct sockaddr *)(void *)p;
    142 				len = SA_RLEN(sa);
    143 				if (i == RTAX_IFA) {
    144 					alen = len;
    145 					break;
    146 				}
    147 				p += len;
    148 			}
    149 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    150 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    151 				    == 0)
    152 					continue;
    153 				sa = (struct sockaddr *)(void *)p;
    154 				len = SA_RLEN(sa);
    155 				if (i == RTAX_NETMASK && sa->sa_len == 0)
    156 					dcnt += alen;
    157 				else
    158 					dcnt += len;
    159 				p += len;
    160 			}
    161 			break;
    162 		}
    163 	}
    164 
    165 	if (icnt + dcnt + ncnt == 1) {
    166 		*pif = NULL;
    167 		free(buf);
    168 		return (0);
    169 	}
    170 	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
    171 	if (data == NULL) {
    172 		free(buf);
    173 		return(-1);
    174 	}
    175 
    176 	ifa = (struct ifaddrs *)(void *)data;
    177 	data += sizeof(struct ifaddrs) * icnt;
    178 	names = data + dcnt;
    179 
    180 	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
    181 	ift = ifa;
    182 
    183 	idx = 0;
    184 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    185 		rtm = (struct rt_msghdr *)(void *)next;
    186 		if (rtm->rtm_version != RTM_VERSION)
    187 			continue;
    188 		switch (rtm->rtm_type) {
    189 		case RTM_IFINFO:
    190 			ifm = (struct if_msghdr *)(void *)rtm;
    191 			if (ifm->ifm_addrs & RTA_IFP) {
    192 				const struct sockaddr_dl *dl;
    193 
    194 				idx = ifm->ifm_index;
    195 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    196 
    197 				memset(&cif, 0, sizeof(cif));
    198 
    199 				cif.ifa_name = names;
    200 				cif.ifa_flags = (int)ifm->ifm_flags;
    201 				memcpy(names, dl->sdl_data,
    202 				    (size_t)dl->sdl_nlen);
    203 				names[dl->sdl_nlen] = 0;
    204 				names += dl->sdl_nlen + 1;
    205 
    206 				cif.ifa_addr = (struct sockaddr *)(void *)data;
    207 				memcpy(data, dl, (size_t)dl->sdl_len);
    208 				data += SA_RLEN((const struct sockaddr *)(const void *)dl);
    209 
    210 				/* ifm_data needs to be aligned */
    211 				cif.ifa_data = data = (void *)ALIGN(data);
    212 				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
    213  				data += sizeof(ifm->ifm_data);
    214 			} else
    215 				idx = 0;
    216 			break;
    217 
    218 		case RTM_NEWADDR:
    219 			ifam = (struct ifa_msghdr *)(void *)rtm;
    220 			if (idx && ifam->ifam_index != idx)
    221 				abort();	/* this cannot happen */
    222 
    223 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    224 				break;
    225 			ift->ifa_name = cif.ifa_name;
    226 			ift->ifa_flags = cif.ifa_flags;
    227 			ift->ifa_data = NULL;
    228 			p = (char *)(void *)(ifam + 1);
    229 			/* Scan to look for length of address */
    230 			alen = 0;
    231 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    232 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    233 				    == 0)
    234 					continue;
    235 				sa = (struct sockaddr *)(void *)p;
    236 				len = SA_RLEN(sa);
    237 				if (i == RTAX_IFA) {
    238 					alen = len;
    239 					break;
    240 				}
    241 				p += len;
    242 			}
    243 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    244 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    245 				    == 0)
    246 					continue;
    247 				sa = (struct sockaddr *)(void *)p;
    248 				len = SA_RLEN(sa);
    249 				switch (i) {
    250 				case RTAX_IFA:
    251 					ift->ifa_addr =
    252 					    (struct sockaddr *)(void *)data;
    253 					memcpy(data, p, len);
    254 					data += len;
    255 					if (ift->ifa_addr->sa_family == AF_LINK)
    256 						ift->ifa_data = cif.ifa_data;
    257 					break;
    258 
    259 				case RTAX_NETMASK:
    260 					ift->ifa_netmask =
    261 					    (struct sockaddr *)(void *)data;
    262 					if (sa->sa_len == 0) {
    263 						memset(data, 0, alen);
    264 						data += alen;
    265 						break;
    266 					}
    267 					memcpy(data, p, len);
    268 					data += len;
    269 					break;
    270 
    271 				case RTAX_BRD:
    272 					ift->ifa_broadaddr =
    273 					    (struct sockaddr *)(void *)data;
    274 					memcpy(data, p, len);
    275 					data += len;
    276 					break;
    277 				}
    278 				p += len;
    279 			}
    280 
    281 
    282 			ift = (ift->ifa_next = ift + 1);
    283 			break;
    284 		}
    285 	}
    286 
    287 	free(buf);
    288 	if (--ift >= ifa) {
    289 		ift->ifa_next = NULL;
    290 		*pif = ifa;
    291 	} else {
    292 		*pif = NULL;
    293 		free(ifa);
    294 	}
    295 	return (0);
    296 }
    297 
    298 void
    299 freeifaddrs(struct ifaddrs *ifp)
    300 {
    301 
    302 	_DIAGASSERT(ifp != NULL);
    303 
    304 	free(ifp);
    305 }
    306