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getifaddrs.c revision 1.6 
      1 /*	$NetBSD: getifaddrs.c,v 1.6 2000/10/27 15:48:49 itojun 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 1.6 2000/10/27 15:48:49 itojun 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 #ifdef	NET_RT_IFLIST
     39 #include <sys/param.h>
     40 #include <net/route.h>
     41 #include <sys/sysctl.h>
     42 #include <net/if_dl.h>
     43 #endif
     44 
     45 #include <errno.h>
     46 #include <ifaddrs.h>
     47 #include <stdlib.h>
     48 #include <string.h>
     49 
     50 #ifdef __weak_alias
     51 __weak_alias(getifaddrs,_getifaddrs)
     52 __weak_alias(freeifaddrs,_freeifaddrs)
     53 #endif
     54 
     55 #if !defined(AF_LINK)
     56 #define	SA_LEN(sa)	sizeof(struct sockaddr)
     57 #endif
     58 
     59 #if !defined(SA_LEN)
     60 #define	SA_LEN(sa)	(sa)->sa_len
     61 #endif
     62 
     63 #define	SALIGN	(sizeof(long) - 1)
     64 #define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
     65 
     66 #ifndef	ALIGNBYTES
     67 /*
     68  * On systems with a routing socket, ALIGNBYTES should match the value
     69  * that the kernel uses when building the messages.
     70  */
     71 #define	ALIGNBYTES	XXX
     72 #endif
     73 #ifndef	ALIGN
     74 #define	ALIGN(p)	(((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
     75 #endif
     76 
     77 #if	_BSDI_VERSION >= 199701
     78 #define	HAVE_IFM_DATA
     79 #endif
     80 
     81 #if	_BSDI_VERSION >= 199802
     82 /* ifam_data is very specific to recent versions of bsdi */
     83 #define	HAVE_IFAM_DATA
     84 #endif
     85 
     86 #if defined(__NetBSD__) || defined(__OpenBSD__) || defined(__FreeBSD__)
     87 #define	HAVE_IFM_DATA
     88 #endif
     89 
     90 int
     91 getifaddrs(struct ifaddrs **pif)
     92 {
     93 	int icnt = 1;
     94 	int dcnt = 0;
     95 	int ncnt = 0;
     96 #ifdef	NET_RT_IFLIST
     97 	int mib[6];
     98 	size_t needed;
     99 	char *buf;
    100 	char *next;
    101 	struct ifaddrs *cif = 0;
    102 	char *p, *p0;
    103 	struct rt_msghdr *rtm;
    104 	struct if_msghdr *ifm;
    105 	struct ifa_msghdr *ifam;
    106 	struct sockaddr_dl *dl;
    107 	struct sockaddr *sa;
    108 	struct ifaddrs *ifa, *ift;
    109 	u_short idx = 0;
    110 #else	/* NET_RT_IFLIST */
    111 	char buf[1024];
    112 	int m, sock;
    113 	struct ifconf ifc;
    114 	struct ifreq *ifr;
    115 	struct ifreq *lifr;
    116 #endif	/* NET_RT_IFLIST */
    117 	int i;
    118 	size_t len, alen;
    119 	char *data;
    120 	char *names;
    121 
    122 #ifdef	NET_RT_IFLIST
    123 	mib[0] = CTL_NET;
    124 	mib[1] = PF_ROUTE;
    125 	mib[2] = 0;             /* protocol */
    126 	mib[3] = 0;             /* wildcard address family */
    127 	mib[4] = NET_RT_IFLIST;
    128 	mib[5] = 0;             /* no flags */
    129 	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
    130 		return (-1);
    131 	if ((buf = malloc(needed)) == NULL)
    132 		return (-1);
    133 	if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
    134 		free(buf);
    135 		return (-1);
    136 	}
    137 
    138 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    139 		rtm = (struct rt_msghdr *)(void *)next;
    140 		if (rtm->rtm_version != RTM_VERSION)
    141 			continue;
    142 		switch (rtm->rtm_type) {
    143 		case RTM_IFINFO:
    144 			ifm = (struct if_msghdr *)(void *)rtm;
    145 			if (ifm->ifm_addrs & RTA_IFP) {
    146 				idx = ifm->ifm_index;
    147 				++icnt;
    148 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    149 				dcnt += SA_RLEN((struct sockaddr *)(void*)dl) +
    150 				    ALIGNBYTES;
    151 #ifdef	HAVE_IFM_DATA
    152 				dcnt += sizeof(ifm->ifm_data);
    153 #endif	/* HAVE_IFM_DATA */
    154 				ncnt += dl->sdl_nlen + 1;
    155 			} else
    156 				idx = 0;
    157 			break;
    158 
    159 		case RTM_NEWADDR:
    160 			ifam = (struct ifa_msghdr *)(void *)rtm;
    161 			if (idx && ifam->ifam_index != idx)
    162 				abort();	/* this cannot happen */
    163 
    164 #define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
    165 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    166 				break;
    167 			p = (char *)(void *)(ifam + 1);
    168 			++icnt;
    169 #ifdef	HAVE_IFAM_DATA
    170 			dcnt += sizeof(ifam->ifam_data) + ALIGNBYTES;
    171 #endif	/* HAVE_IFAM_DATA */
    172 			/* Scan to look for length of address */
    173 			alen = 0;
    174 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    175 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    176 				    == 0)
    177 					continue;
    178 				sa = (struct sockaddr *)(void *)p;
    179 				len = SA_RLEN(sa);
    180 				if (i == RTAX_IFA) {
    181 					alen = len;
    182 					break;
    183 				}
    184 				p += len;
    185 			}
    186 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    187 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    188 				    == 0)
    189 					continue;
    190 				sa = (struct sockaddr *)(void *)p;
    191 				len = SA_RLEN(sa);
    192 				if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
    193 					dcnt += alen;
    194 				else
    195 					dcnt += len;
    196 				p += len;
    197 			}
    198 			break;
    199 		}
    200 	}
    201 #else	/* NET_RT_IFLIST */
    202 	ifc.ifc_buf = buf;
    203 	ifc.ifc_len = sizeof(buf);
    204 
    205 	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    206 		return (-1);
    207 	i =  ioctl(sock, SIOCGIFCONF, (char *)&ifc);
    208 	close(sock);
    209 	if (i < 0)
    210 		return (-1);
    211 
    212 	ifr = ifc.ifc_req;
    213 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
    214 
    215 	while (ifr < lifr) {
    216 		struct sockaddr *sa;
    217 
    218 		sa = &ifr->ifr_addr;
    219 		++icnt;
    220 		dcnt += SA_RLEN(sa);
    221 		ncnt += sizeof(ifr->ifr_name) + 1;
    222 
    223 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
    224 	}
    225 #endif	/* NET_RT_IFLIST */
    226 
    227 	if (icnt + dcnt + ncnt == 1) {
    228 		*pif = NULL;
    229 		free(buf);
    230 		return (0);
    231 	}
    232 	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
    233 	if (data == NULL) {
    234 		free(buf);
    235 		return(-1);
    236 	}
    237 
    238 	ifa = (struct ifaddrs *)(void *)data;
    239 	data += sizeof(struct ifaddrs) * icnt;
    240 	names = data + dcnt;
    241 
    242 	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
    243 	ift = ifa;
    244 
    245 #ifdef	NET_RT_IFLIST
    246 	idx = 0;
    247 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    248 		rtm = (struct rt_msghdr *)(void *)next;
    249 		if (rtm->rtm_version != RTM_VERSION)
    250 			continue;
    251 		switch (rtm->rtm_type) {
    252 		case RTM_IFINFO:
    253 			ifm = (struct if_msghdr *)(void *)rtm;
    254 			if (ifm->ifm_addrs & RTA_IFP) {
    255 				idx = ifm->ifm_index;
    256 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    257 
    258 				cif = ift;
    259 				ift->ifa_name = names;
    260 				ift->ifa_flags = (int)ifm->ifm_flags;
    261 				memcpy(names, dl->sdl_data,
    262 				    (size_t)dl->sdl_nlen);
    263 				names[dl->sdl_nlen] = 0;
    264 				names += dl->sdl_nlen + 1;
    265 
    266 				ift->ifa_addr = (struct sockaddr *)(void *)data;
    267 				memcpy(data, dl,
    268 				    (size_t)SA_LEN((struct sockaddr *)
    269 				    (void *)dl));
    270 				data += SA_RLEN((struct sockaddr *)(void *)dl);
    271 
    272 #ifdef	HAVE_IFM_DATA
    273 				/* ifm_data needs to be aligned */
    274 				ift->ifa_data = data = (void *)ALIGN(data);
    275 				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
    276  				data += sizeof(ifm->ifm_data);
    277 #else	/* HAVE_IFM_DATA */
    278 				ift->ifa_data = NULL;
    279 #endif	/* HAVE_IFM_DATA */
    280 
    281 				ift = (ift->ifa_next = ift + 1);
    282 			} else
    283 				idx = 0;
    284 			break;
    285 
    286 		case RTM_NEWADDR:
    287 			ifam = (struct ifa_msghdr *)(void *)rtm;
    288 			if (idx && ifam->ifam_index != idx)
    289 				abort();	/* this cannot happen */
    290 
    291 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    292 				break;
    293 			ift->ifa_name = cif->ifa_name;
    294 			ift->ifa_flags = cif->ifa_flags;
    295 			ift->ifa_data = NULL;
    296 			p = (char *)(void *)(ifam + 1);
    297 			/* Scan to look for length of address */
    298 			alen = 0;
    299 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    300 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    301 				    == 0)
    302 					continue;
    303 				sa = (struct sockaddr *)(void *)p;
    304 				len = SA_RLEN(sa);
    305 				if (i == RTAX_IFA) {
    306 					alen = len;
    307 					break;
    308 				}
    309 				p += len;
    310 			}
    311 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    312 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    313 				    == 0)
    314 					continue;
    315 				sa = (struct sockaddr *)(void *)p;
    316 				len = SA_RLEN(sa);
    317 				switch (i) {
    318 				case RTAX_IFA:
    319 					ift->ifa_addr =
    320 					    (struct sockaddr *)(void *)data;
    321 					memcpy(data, p, len);
    322 					data += len;
    323 					break;
    324 
    325 				case RTAX_NETMASK:
    326 					ift->ifa_netmask =
    327 					    (struct sockaddr *)(void *)data;
    328 					if (SA_LEN(sa) == 0) {
    329 						memset(data, 0, alen);
    330 						data += alen;
    331 						break;
    332 					}
    333 					memcpy(data, p, len);
    334 					data += len;
    335 					break;
    336 
    337 				case RTAX_BRD:
    338 					ift->ifa_broadaddr =
    339 					    (struct sockaddr *)(void *)data;
    340 					memcpy(data, p, len);
    341 					data += len;
    342 					break;
    343 				}
    344 				p += len;
    345 			}
    346 
    347 #ifdef	HAVE_IFAM_DATA
    348 			/* ifam_data needs to be aligned */
    349 			ift->ifa_data = data = (void *)ALIGN(data);
    350 			memcpy(data, &ifam->ifam_data, sizeof(ifam->ifam_data));
    351 			data += sizeof(ifam->ifam_data);
    352 #endif	/* HAVE_IFAM_DATA */
    353 
    354 			ift = (ift->ifa_next = ift + 1);
    355 			break;
    356 		}
    357 	}
    358 
    359 	free(buf);
    360 #else	/* NET_RT_IFLIST */
    361 	ifr = ifc.ifc_req;
    362 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
    363 
    364 	while (ifr < lifr) {
    365 		struct sockaddr *sa;
    366 
    367 		ift->ifa_name = names;
    368 		names[sizeof(ifr->ifr_name)] = 0;
    369 		strncpy(names, ifr->ifr_name, sizeof(ifr->ifr_name));
    370 		while (*names++)
    371 			;
    372 
    373 		ift->ifa_addr = (struct sockaddr *)data;
    374 		sa = &ifr->ifr_addr;
    375 		memcpy(data, sa, SA_LEN(sa));
    376 		data += SA_RLEN(sa);
    377 
    378 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
    379 		ift = (ift->ifa_next = ift + 1);
    380 	}
    381 #endif	/* NET_RT_IFLIST */
    382 	if (--ift >= ifa) {
    383 		ift->ifa_next = NULL;
    384 		*pif = ifa;
    385 	} else {
    386 		*pif = NULL;
    387 		free(ifa);
    388 	}
    389 	return (0);
    390 }
    391 
    392 void
    393 freeifaddrs(struct ifaddrs *ifp)
    394 {
    395 	free(ifp);
    396 }
    397