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getifaddrs.c revision 1.7 
      1 /*	$NetBSD: getifaddrs.c,v 1.7 2001/01/04 03:57:58 lukem 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 1.7 2001/01/04 03:57:58 lukem 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 <assert.h>
     46 #include <errno.h>
     47 #include <ifaddrs.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 
     51 #ifdef __weak_alias
     52 __weak_alias(getifaddrs,_getifaddrs)
     53 __weak_alias(freeifaddrs,_freeifaddrs)
     54 #endif
     55 
     56 #if !defined(AF_LINK)
     57 #define	SA_LEN(sa)	sizeof(struct sockaddr)
     58 #endif
     59 
     60 #if !defined(SA_LEN)
     61 #define	SA_LEN(sa)	(sa)->sa_len
     62 #endif
     63 
     64 #define	SALIGN	(sizeof(long) - 1)
     65 #define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
     66 
     67 #ifndef	ALIGNBYTES
     68 /*
     69  * On systems with a routing socket, ALIGNBYTES should match the value
     70  * that the kernel uses when building the messages.
     71  */
     72 #define	ALIGNBYTES	XXX
     73 #endif
     74 #ifndef	ALIGN
     75 #define	ALIGN(p)	(((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
     76 #endif
     77 
     78 #if	_BSDI_VERSION >= 199701
     79 #define	HAVE_IFM_DATA
     80 #endif
     81 
     82 #if	_BSDI_VERSION >= 199802
     83 /* ifam_data is very specific to recent versions of bsdi */
     84 #define	HAVE_IFAM_DATA
     85 #endif
     86 
     87 #if defined(__NetBSD__) || defined(__OpenBSD__) || defined(__FreeBSD__)
     88 #define	HAVE_IFM_DATA
     89 #endif
     90 
     91 int
     92 getifaddrs(struct ifaddrs **pif)
     93 {
     94 	int icnt = 1;
     95 	int dcnt = 0;
     96 	int ncnt = 0;
     97 #ifdef	NET_RT_IFLIST
     98 	int mib[6];
     99 	size_t needed;
    100 	char *buf;
    101 	char *next;
    102 	struct ifaddrs *cif = 0;
    103 	char *p, *p0;
    104 	struct rt_msghdr *rtm;
    105 	struct if_msghdr *ifm;
    106 	struct ifa_msghdr *ifam;
    107 	struct sockaddr_dl *dl;
    108 	struct sockaddr *sa;
    109 	struct ifaddrs *ifa, *ift;
    110 	u_short idx = 0;
    111 #else	/* NET_RT_IFLIST */
    112 	char buf[1024];
    113 	int m, sock;
    114 	struct ifconf ifc;
    115 	struct ifreq *ifr;
    116 	struct ifreq *lifr;
    117 #endif	/* NET_RT_IFLIST */
    118 	int i;
    119 	size_t len, alen;
    120 	char *data;
    121 	char *names;
    122 
    123 	_DIAGASSERT(pif != NULL);
    124 
    125 #ifdef	NET_RT_IFLIST
    126 	mib[0] = CTL_NET;
    127 	mib[1] = PF_ROUTE;
    128 	mib[2] = 0;             /* protocol */
    129 	mib[3] = 0;             /* wildcard address family */
    130 	mib[4] = NET_RT_IFLIST;
    131 	mib[5] = 0;             /* no flags */
    132 	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
    133 		return (-1);
    134 	if ((buf = malloc(needed)) == NULL)
    135 		return (-1);
    136 	if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
    137 		free(buf);
    138 		return (-1);
    139 	}
    140 
    141 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    142 		rtm = (struct rt_msghdr *)(void *)next;
    143 		if (rtm->rtm_version != RTM_VERSION)
    144 			continue;
    145 		switch (rtm->rtm_type) {
    146 		case RTM_IFINFO:
    147 			ifm = (struct if_msghdr *)(void *)rtm;
    148 			if (ifm->ifm_addrs & RTA_IFP) {
    149 				idx = ifm->ifm_index;
    150 				++icnt;
    151 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    152 				dcnt += SA_RLEN((struct sockaddr *)(void*)dl) +
    153 				    ALIGNBYTES;
    154 #ifdef	HAVE_IFM_DATA
    155 				dcnt += sizeof(ifm->ifm_data);
    156 #endif	/* HAVE_IFM_DATA */
    157 				ncnt += dl->sdl_nlen + 1;
    158 			} else
    159 				idx = 0;
    160 			break;
    161 
    162 		case RTM_NEWADDR:
    163 			ifam = (struct ifa_msghdr *)(void *)rtm;
    164 			if (idx && ifam->ifam_index != idx)
    165 				abort();	/* this cannot happen */
    166 
    167 #define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
    168 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    169 				break;
    170 			p = (char *)(void *)(ifam + 1);
    171 			++icnt;
    172 #ifdef	HAVE_IFAM_DATA
    173 			dcnt += sizeof(ifam->ifam_data) + ALIGNBYTES;
    174 #endif	/* HAVE_IFAM_DATA */
    175 			/* Scan to look for length of address */
    176 			alen = 0;
    177 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    178 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    179 				    == 0)
    180 					continue;
    181 				sa = (struct sockaddr *)(void *)p;
    182 				len = SA_RLEN(sa);
    183 				if (i == RTAX_IFA) {
    184 					alen = len;
    185 					break;
    186 				}
    187 				p += len;
    188 			}
    189 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    190 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    191 				    == 0)
    192 					continue;
    193 				sa = (struct sockaddr *)(void *)p;
    194 				len = SA_RLEN(sa);
    195 				if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
    196 					dcnt += alen;
    197 				else
    198 					dcnt += len;
    199 				p += len;
    200 			}
    201 			break;
    202 		}
    203 	}
    204 #else	/* NET_RT_IFLIST */
    205 	ifc.ifc_buf = buf;
    206 	ifc.ifc_len = sizeof(buf);
    207 
    208 	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    209 		return (-1);
    210 	i =  ioctl(sock, SIOCGIFCONF, (char *)&ifc);
    211 	close(sock);
    212 	if (i < 0)
    213 		return (-1);
    214 
    215 	ifr = ifc.ifc_req;
    216 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
    217 
    218 	while (ifr < lifr) {
    219 		struct sockaddr *sa;
    220 
    221 		sa = &ifr->ifr_addr;
    222 		++icnt;
    223 		dcnt += SA_RLEN(sa);
    224 		ncnt += sizeof(ifr->ifr_name) + 1;
    225 
    226 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
    227 	}
    228 #endif	/* NET_RT_IFLIST */
    229 
    230 	if (icnt + dcnt + ncnt == 1) {
    231 		*pif = NULL;
    232 		free(buf);
    233 		return (0);
    234 	}
    235 	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
    236 	if (data == NULL) {
    237 		free(buf);
    238 		return(-1);
    239 	}
    240 
    241 	ifa = (struct ifaddrs *)(void *)data;
    242 	data += sizeof(struct ifaddrs) * icnt;
    243 	names = data + dcnt;
    244 
    245 	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
    246 	ift = ifa;
    247 
    248 #ifdef	NET_RT_IFLIST
    249 	idx = 0;
    250 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    251 		rtm = (struct rt_msghdr *)(void *)next;
    252 		if (rtm->rtm_version != RTM_VERSION)
    253 			continue;
    254 		switch (rtm->rtm_type) {
    255 		case RTM_IFINFO:
    256 			ifm = (struct if_msghdr *)(void *)rtm;
    257 			if (ifm->ifm_addrs & RTA_IFP) {
    258 				idx = ifm->ifm_index;
    259 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    260 
    261 				cif = ift;
    262 				ift->ifa_name = names;
    263 				ift->ifa_flags = (int)ifm->ifm_flags;
    264 				memcpy(names, dl->sdl_data,
    265 				    (size_t)dl->sdl_nlen);
    266 				names[dl->sdl_nlen] = 0;
    267 				names += dl->sdl_nlen + 1;
    268 
    269 				ift->ifa_addr = (struct sockaddr *)(void *)data;
    270 				memcpy(data, dl,
    271 				    (size_t)SA_LEN((struct sockaddr *)
    272 				    (void *)dl));
    273 				data += SA_RLEN((struct sockaddr *)(void *)dl);
    274 
    275 #ifdef	HAVE_IFM_DATA
    276 				/* ifm_data needs to be aligned */
    277 				ift->ifa_data = data = (void *)ALIGN(data);
    278 				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
    279  				data += sizeof(ifm->ifm_data);
    280 #else	/* HAVE_IFM_DATA */
    281 				ift->ifa_data = NULL;
    282 #endif	/* HAVE_IFM_DATA */
    283 
    284 				ift = (ift->ifa_next = ift + 1);
    285 			} else
    286 				idx = 0;
    287 			break;
    288 
    289 		case RTM_NEWADDR:
    290 			ifam = (struct ifa_msghdr *)(void *)rtm;
    291 			if (idx && ifam->ifam_index != idx)
    292 				abort();	/* this cannot happen */
    293 
    294 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    295 				break;
    296 			ift->ifa_name = cif->ifa_name;
    297 			ift->ifa_flags = cif->ifa_flags;
    298 			ift->ifa_data = NULL;
    299 			p = (char *)(void *)(ifam + 1);
    300 			/* Scan to look for length of address */
    301 			alen = 0;
    302 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    303 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    304 				    == 0)
    305 					continue;
    306 				sa = (struct sockaddr *)(void *)p;
    307 				len = SA_RLEN(sa);
    308 				if (i == RTAX_IFA) {
    309 					alen = len;
    310 					break;
    311 				}
    312 				p += len;
    313 			}
    314 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    315 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    316 				    == 0)
    317 					continue;
    318 				sa = (struct sockaddr *)(void *)p;
    319 				len = SA_RLEN(sa);
    320 				switch (i) {
    321 				case RTAX_IFA:
    322 					ift->ifa_addr =
    323 					    (struct sockaddr *)(void *)data;
    324 					memcpy(data, p, len);
    325 					data += len;
    326 					break;
    327 
    328 				case RTAX_NETMASK:
    329 					ift->ifa_netmask =
    330 					    (struct sockaddr *)(void *)data;
    331 					if (SA_LEN(sa) == 0) {
    332 						memset(data, 0, alen);
    333 						data += alen;
    334 						break;
    335 					}
    336 					memcpy(data, p, len);
    337 					data += len;
    338 					break;
    339 
    340 				case RTAX_BRD:
    341 					ift->ifa_broadaddr =
    342 					    (struct sockaddr *)(void *)data;
    343 					memcpy(data, p, len);
    344 					data += len;
    345 					break;
    346 				}
    347 				p += len;
    348 			}
    349 
    350 #ifdef	HAVE_IFAM_DATA
    351 			/* ifam_data needs to be aligned */
    352 			ift->ifa_data = data = (void *)ALIGN(data);
    353 			memcpy(data, &ifam->ifam_data, sizeof(ifam->ifam_data));
    354 			data += sizeof(ifam->ifam_data);
    355 #endif	/* HAVE_IFAM_DATA */
    356 
    357 			ift = (ift->ifa_next = ift + 1);
    358 			break;
    359 		}
    360 	}
    361 
    362 	free(buf);
    363 #else	/* NET_RT_IFLIST */
    364 	ifr = ifc.ifc_req;
    365 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
    366 
    367 	while (ifr < lifr) {
    368 		struct sockaddr *sa;
    369 
    370 		ift->ifa_name = names;
    371 		names[sizeof(ifr->ifr_name)] = 0;
    372 		strncpy(names, ifr->ifr_name, sizeof(ifr->ifr_name));
    373 		while (*names++)
    374 			;
    375 
    376 		ift->ifa_addr = (struct sockaddr *)data;
    377 		sa = &ifr->ifr_addr;
    378 		memcpy(data, sa, SA_LEN(sa));
    379 		data += SA_RLEN(sa);
    380 
    381 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
    382 		ift = (ift->ifa_next = ift + 1);
    383 	}
    384 #endif	/* NET_RT_IFLIST */
    385 	if (--ift >= ifa) {
    386 		ift->ifa_next = NULL;
    387 		*pif = ifa;
    388 	} else {
    389 		*pif = NULL;
    390 		free(ifa);
    391 	}
    392 	return (0);
    393 }
    394 
    395 void
    396 freeifaddrs(struct ifaddrs *ifp)
    397 {
    398 
    399 	_DIAGASSERT(ifp != NULL);
    400 
    401 	free(ifp);
    402 }
    403