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getifaddrs.c revision 1.5 
      1 /*	$NetBSD: getifaddrs.c,v 1.5 2000/07/06 02:53:12 christos 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 1.5 2000/07/06 02:53:12 christos 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 #define	HAVE_IFAM_DATA
     83 #endif
     84 
     85 int
     86 getifaddrs(struct ifaddrs **pif)
     87 {
     88 	int icnt = 1;
     89 	int dcnt = 0;
     90 	int ncnt = 0;
     91 #ifdef	NET_RT_IFLIST
     92 	int mib[6];
     93 	size_t needed;
     94 	char *buf;
     95 	char *next;
     96 	struct ifaddrs *cif = 0;
     97 	char *p, *p0;
     98 	struct rt_msghdr *rtm;
     99 	struct if_msghdr *ifm;
    100 	struct ifa_msghdr *ifam;
    101 	struct sockaddr_dl *dl;
    102 	struct sockaddr *sa;
    103 	struct ifaddrs *ifa, *ift;
    104 	u_short idx = 0;
    105 #else	/* NET_RT_IFLIST */
    106 	char buf[1024];
    107 	int m, sock;
    108 	struct ifconf ifc;
    109 	struct ifreq *ifr;
    110 	struct ifreq *lifr;
    111 #endif	/* NET_RT_IFLIST */
    112 	int i;
    113 	size_t len, alen;
    114 	char *data;
    115 	char *names;
    116 
    117 #ifdef	NET_RT_IFLIST
    118 	mib[0] = CTL_NET;
    119 	mib[1] = PF_ROUTE;
    120 	mib[2] = 0;             /* protocol */
    121 	mib[3] = 0;             /* wildcard address family */
    122 	mib[4] = NET_RT_IFLIST;
    123 	mib[5] = 0;             /* no flags */
    124 	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
    125 		return (-1);
    126 	if ((buf = malloc(needed)) == NULL)
    127 		return (-1);
    128 	if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
    129 		free(buf);
    130 		return (-1);
    131 	}
    132 
    133 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    134 		rtm = (struct rt_msghdr *)(void *)next;
    135 		if (rtm->rtm_version != RTM_VERSION)
    136 			continue;
    137 		switch (rtm->rtm_type) {
    138 		case RTM_IFINFO:
    139 			ifm = (struct if_msghdr *)(void *)rtm;
    140 			if (ifm->ifm_addrs & RTA_IFP) {
    141 				idx = ifm->ifm_index;
    142 				++icnt;
    143 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    144 				dcnt += SA_RLEN((struct sockaddr *)(void*)dl) +
    145 				    ALIGNBYTES;
    146 #ifdef	HAVE_IFM_DATA
    147 				dcnt += sizeof(ifm->ifm_data);
    148 #endif	/* HAVE_IFM_DATA */
    149 				ncnt += dl->sdl_nlen + 1;
    150 			} else
    151 				idx = 0;
    152 			break;
    153 
    154 		case RTM_NEWADDR:
    155 			ifam = (struct ifa_msghdr *)(void *)rtm;
    156 			if (idx && ifam->ifam_index != idx)
    157 				abort();	/* this cannot happen */
    158 
    159 #define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
    160 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    161 				break;
    162 			p = (char *)(void *)(ifam + 1);
    163 			++icnt;
    164 #ifdef	HAVE_IFAM_DATA
    165 			dcnt += sizeof(ifam->ifam_data) + ALIGNBYTES;
    166 #endif	/* HAVE_IFAM_DATA */
    167 			/* Scan to look for length of address */
    168 			alen = 0;
    169 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    170 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    171 				    == 0)
    172 					continue;
    173 				sa = (struct sockaddr *)(void *)p;
    174 				len = SA_RLEN(sa);
    175 				if (i == RTAX_IFA) {
    176 					alen = len;
    177 					break;
    178 				}
    179 				p += len;
    180 			}
    181 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    182 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    183 				    == 0)
    184 					continue;
    185 				sa = (struct sockaddr *)(void *)p;
    186 				len = SA_RLEN(sa);
    187 				if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
    188 					dcnt += alen;
    189 				else
    190 					dcnt += len;
    191 				p += len;
    192 			}
    193 			break;
    194 		}
    195 	}
    196 #else	/* NET_RT_IFLIST */
    197 	ifc.ifc_buf = buf;
    198 	ifc.ifc_len = sizeof(buf);
    199 
    200 	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    201 		return (-1);
    202 	i =  ioctl(sock, SIOCGIFCONF, (char *)&ifc);
    203 	close(sock);
    204 	if (i < 0)
    205 		return (-1);
    206 
    207 	ifr = ifc.ifc_req;
    208 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
    209 
    210 	while (ifr < lifr) {
    211 		struct sockaddr *sa;
    212 
    213 		sa = &ifr->ifr_addr;
    214 		++icnt;
    215 		dcnt += SA_RLEN(sa);
    216 		ncnt += sizeof(ifr->ifr_name) + 1;
    217 
    218 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
    219 	}
    220 #endif	/* NET_RT_IFLIST */
    221 
    222 	if (icnt + dcnt + ncnt == 1) {
    223 		*pif = NULL;
    224 		free(buf);
    225 		return (0);
    226 	}
    227 	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
    228 	if (data == NULL) {
    229 		free(buf);
    230 		return(-1);
    231 	}
    232 
    233 	ifa = (struct ifaddrs *)(void *)data;
    234 	data += sizeof(struct ifaddrs) * icnt;
    235 	names = data + dcnt;
    236 
    237 	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
    238 	ift = ifa;
    239 
    240 #ifdef	NET_RT_IFLIST
    241 	idx = 0;
    242 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
    243 		rtm = (struct rt_msghdr *)(void *)next;
    244 		if (rtm->rtm_version != RTM_VERSION)
    245 			continue;
    246 		switch (rtm->rtm_type) {
    247 		case RTM_IFINFO:
    248 			ifm = (struct if_msghdr *)(void *)rtm;
    249 			if (ifm->ifm_addrs & RTA_IFP) {
    250 				idx = ifm->ifm_index;
    251 				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
    252 
    253 				cif = ift;
    254 				ift->ifa_name = names;
    255 				ift->ifa_flags = (int)ifm->ifm_flags;
    256 				memcpy(names, dl->sdl_data,
    257 				    (size_t)dl->sdl_nlen);
    258 				names[dl->sdl_nlen] = 0;
    259 				names += dl->sdl_nlen + 1;
    260 
    261 				ift->ifa_addr = (struct sockaddr *)(void *)data;
    262 				memcpy(data, dl,
    263 				    (size_t)SA_LEN((struct sockaddr *)
    264 				    (void *)dl));
    265 				data += SA_RLEN((struct sockaddr *)(void *)dl);
    266 
    267 #ifdef	HAVE_IFM_DATA
    268 				/* ifm_data needs to be aligned */
    269 				ift->ifa_data = data = (void *)ALIGN(data);
    270 				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
    271  				data += sizeof(ifm->ifm_data);
    272 #else	/* HAVE_IFM_DATA */
    273 				ift->ifa_data = NULL;
    274 #endif	/* HAVE_IFM_DATA */
    275 
    276 				ift = (ift->ifa_next = ift + 1);
    277 			} else
    278 				idx = 0;
    279 			break;
    280 
    281 		case RTM_NEWADDR:
    282 			ifam = (struct ifa_msghdr *)(void *)rtm;
    283 			if (idx && ifam->ifam_index != idx)
    284 				abort();	/* this cannot happen */
    285 
    286 			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
    287 				break;
    288 			ift->ifa_name = cif->ifa_name;
    289 			ift->ifa_flags = cif->ifa_flags;
    290 			ift->ifa_data = NULL;
    291 			p = (char *)(void *)(ifam + 1);
    292 			/* Scan to look for length of address */
    293 			alen = 0;
    294 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
    295 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    296 				    == 0)
    297 					continue;
    298 				sa = (struct sockaddr *)(void *)p;
    299 				len = SA_RLEN(sa);
    300 				if (i == RTAX_IFA) {
    301 					alen = len;
    302 					break;
    303 				}
    304 				p += len;
    305 			}
    306 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
    307 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
    308 				    == 0)
    309 					continue;
    310 				sa = (struct sockaddr *)(void *)p;
    311 				len = SA_RLEN(sa);
    312 				switch (i) {
    313 				case RTAX_IFA:
    314 					ift->ifa_addr =
    315 					    (struct sockaddr *)(void *)data;
    316 					memcpy(data, p, len);
    317 					data += len;
    318 					break;
    319 
    320 				case RTAX_NETMASK:
    321 					ift->ifa_netmask =
    322 					    (struct sockaddr *)(void *)data;
    323 					if (SA_LEN(sa) == 0) {
    324 						memset(data, 0, alen);
    325 						data += alen;
    326 						break;
    327 					}
    328 					memcpy(data, p, len);
    329 					data += len;
    330 					break;
    331 
    332 				case RTAX_BRD:
    333 					ift->ifa_broadaddr =
    334 					    (struct sockaddr *)(void *)data;
    335 					memcpy(data, p, len);
    336 					data += len;
    337 					break;
    338 				}
    339 				p += len;
    340 			}
    341 
    342 #ifdef	HAVE_IFAM_DATA
    343 			/* ifam_data needs to be aligned */
    344 			ift->ifa_data = data = (void *)ALIGN(data);
    345 			memcpy(data, &ifam->ifam_data, sizeof(ifam->ifam_data));
    346 			data += sizeof(ifam->ifam_data);
    347 #endif	/* HAVE_IFAM_DATA */
    348 
    349 			ift = (ift->ifa_next = ift + 1);
    350 			break;
    351 		}
    352 	}
    353 
    354 	free(buf);
    355 #else	/* NET_RT_IFLIST */
    356 	ifr = ifc.ifc_req;
    357 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
    358 
    359 	while (ifr < lifr) {
    360 		struct sockaddr *sa;
    361 
    362 		ift->ifa_name = names;
    363 		names[sizeof(ifr->ifr_name)] = 0;
    364 		strncpy(names, ifr->ifr_name, sizeof(ifr->ifr_name));
    365 		while (*names++)
    366 			;
    367 
    368 		ift->ifa_addr = (struct sockaddr *)data;
    369 		sa = &ifr->ifr_addr;
    370 		memcpy(data, sa, SA_LEN(sa));
    371 		data += SA_RLEN(sa);
    372 
    373 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
    374 		ift = (ift->ifa_next = ift + 1);
    375 	}
    376 #endif	/* NET_RT_IFLIST */
    377 	if (--ift >= ifa) {
    378 		ift->ifa_next = NULL;
    379 		*pif = ifa;
    380 	} else {
    381 		*pif = NULL;
    382 		free(ifa);
    383 	}
    384 	return (0);
    385 }
    386 
    387 void
    388 freeifaddrs(struct ifaddrs *ifp)
    389 {
    390 	free(ifp);
    391 }
    392