xref: /freebsd/lib/libc/net/getifaddrs.c (revision b601c69bdbe8755d26570261d7fd4c02ee4eff74)
1 /*	$FreeBSD$	*/
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  * NOTE: SIOCGIFCONF case is not LP64 friendly.  it also does not perform
29  * try-and-error for region size.
30  */
31 #include <sys/types.h>
32 #include <sys/ioctl.h>
33 #include <sys/socket.h>
34 #include <net/if.h>
35 #ifdef	NET_RT_IFLIST
36 #include <sys/param.h>
37 #include <net/route.h>
38 #include <sys/sysctl.h>
39 #include <net/if_dl.h>
40 #endif
41 
42 #include <errno.h>
43 #include <ifaddrs.h>
44 #include <stdlib.h>
45 #include <string.h>
46 
47 #if !defined(AF_LINK)
48 #define	SA_LEN(sa)	sizeof(struct sockaddr)
49 #endif
50 
51 #if !defined(SA_LEN)
52 #define	SA_LEN(sa)	(sa)->sa_len
53 #endif
54 
55 #define	SALIGN	(sizeof(long) - 1)
56 #define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
57 
58 #ifndef	ALIGNBYTES
59 /*
60  * On systems with a routing socket, ALIGNBYTES should match the value
61  * that the kernel uses when building the messages.
62  */
63 #define	ALIGNBYTES	XXX
64 #endif
65 #ifndef	ALIGN
66 #define	ALIGN(p)	(((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
67 #endif
68 
69 #if	_BSDI_VERSION >= 199701
70 #define	HAVE_IFM_DATA
71 #endif
72 
73 #if	_BSDI_VERSION >= 199802
74 #define	HAVE_IFAM_DATA
75 #endif
76 
77 int
78 getifaddrs(struct ifaddrs **pif)
79 {
80 	int icnt = 1;
81 	int dcnt = 0;
82 	int ncnt = 0;
83 #ifdef	NET_RT_IFLIST
84 	int mib[6];
85 	size_t needed;
86 	char *buf;
87 	char *next;
88 	struct ifaddrs *cif = 0;
89 	char *p, *p0;
90 	struct rt_msghdr *rtm;
91 	struct if_msghdr *ifm;
92 	struct ifa_msghdr *ifam;
93 	struct sockaddr_dl *dl;
94 	struct sockaddr *sa;
95 	struct ifaddrs *ifa, *ift;
96 	u_short index = 0;
97 #else	/* NET_RT_IFLIST */
98 	char buf[1024];
99 	int m, sock;
100 	struct ifconf ifc;
101 	struct ifreq *ifr;
102 	struct ifreq *lifr;
103 #endif	/* NET_RT_IFLIST */
104 	int i;
105 	size_t len, alen;
106 	char *data;
107 	char *names;
108 
109 #ifdef	NET_RT_IFLIST
110 	mib[0] = CTL_NET;
111 	mib[1] = PF_ROUTE;
112 	mib[2] = 0;             /* protocol */
113 	mib[3] = 0;             /* wildcard address family */
114 	mib[4] = NET_RT_IFLIST;
115 	mib[5] = 0;             /* no flags */
116 	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
117 		return (-1);
118 	if ((buf = malloc(needed)) == NULL)
119 		return (-1);
120 	if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
121 		free(buf);
122 		return (-1);
123 	}
124 
125 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
126 		rtm = (struct rt_msghdr *)next;
127 		if (rtm->rtm_version != RTM_VERSION)
128 			continue;
129 		switch (rtm->rtm_type) {
130 		case RTM_IFINFO:
131 			ifm = (struct if_msghdr *)rtm;
132 			if (ifm->ifm_addrs & RTA_IFP) {
133 				index = ifm->ifm_index;
134 				++icnt;
135 				dl = (struct sockaddr_dl *)(ifm + 1);
136 				dcnt += SA_RLEN((struct sockaddr *)dl) +
137 					ALIGNBYTES;
138 #ifdef	HAVE_IFM_DATA
139 				dcnt += sizeof(ifm->ifm_data);
140 #endif	/* HAVE_IFM_DATA */
141 				ncnt += dl->sdl_nlen + 1;
142 			} else
143 				index = 0;
144 			break;
145 
146 		case RTM_NEWADDR:
147 			ifam = (struct ifa_msghdr *)rtm;
148 			if (index && ifam->ifam_index != index)
149 				abort();	/* this cannot happen */
150 
151 #define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
152 			if (index == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
153 				break;
154 			p = (char *)(ifam + 1);
155 			++icnt;
156 #ifdef	HAVE_IFAM_DATA
157 			dcnt += sizeof(ifam->ifam_data) + ALIGNBYTES;
158 #endif	/* HAVE_IFAM_DATA */
159 			/* Scan to look for length of address */
160 			alen = 0;
161 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
162 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
163 				    == 0)
164 					continue;
165 				sa = (struct sockaddr *)p;
166 				len = SA_RLEN(sa);
167 				if (i == RTAX_IFA) {
168 					alen = len;
169 					break;
170 				}
171 				p += len;
172 			}
173 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
174 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
175 				    == 0)
176 					continue;
177 				sa = (struct sockaddr *)p;
178 				len = SA_RLEN(sa);
179 				if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
180 					dcnt += alen;
181 				else
182 					dcnt += len;
183 				p += len;
184 			}
185 			break;
186 		}
187 	}
188 #else	/* NET_RT_IFLIST */
189 	ifc.ifc_buf = buf;
190 	ifc.ifc_len = sizeof(buf);
191 
192 	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
193 		return (-1);
194 	i =  ioctl(sock, SIOCGIFCONF, (char *)&ifc);
195 	close(sock);
196 	if (i < 0)
197 		return (-1);
198 
199 	ifr = ifc.ifc_req;
200 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
201 
202 	while (ifr < lifr) {
203 		struct sockaddr *sa;
204 
205 		sa = &ifr->ifr_addr;
206 		++icnt;
207 		dcnt += SA_RLEN(sa);
208 		ncnt += sizeof(ifr->ifr_name) + 1;
209 
210 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
211 	}
212 #endif	/* NET_RT_IFLIST */
213 
214 	if (icnt + dcnt + ncnt == 1) {
215 		*pif = NULL;
216 		free(buf);
217 		return (0);
218 	}
219 	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
220 	if (data == NULL) {
221 		free(buf);
222 		return(-1);
223 	}
224 
225 	ifa = (struct ifaddrs *)data;
226 	data += sizeof(struct ifaddrs) * icnt;
227 	names = data + dcnt;
228 
229 	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
230 	ift = ifa;
231 
232 #ifdef	NET_RT_IFLIST
233 	index = 0;
234 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
235 		rtm = (struct rt_msghdr *)next;
236 		if (rtm->rtm_version != RTM_VERSION)
237 			continue;
238 		switch (rtm->rtm_type) {
239 		case RTM_IFINFO:
240 			ifm = (struct if_msghdr *)rtm;
241 			if (ifm->ifm_addrs & RTA_IFP) {
242 				index = ifm->ifm_index;
243 				dl = (struct sockaddr_dl *)(ifm + 1);
244 
245 				cif = ift;
246 				ift->ifa_name = names;
247 				ift->ifa_flags = (int)ifm->ifm_flags;
248 				memcpy(names, dl->sdl_data, dl->sdl_nlen);
249 				names[dl->sdl_nlen] = 0;
250 				names += dl->sdl_nlen + 1;
251 
252 				ift->ifa_addr = (struct sockaddr *)data;
253 				memcpy(data, dl, SA_LEN((struct sockaddr *)dl));
254 				data += SA_RLEN((struct sockaddr *)dl);
255 
256 #ifdef	HAVE_IFM_DATA
257 				/* ifm_data needs to be aligned */
258 				ift->ifa_data = data = (void *)ALIGN(data);
259 				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
260  				data += sizeof(ifm->ifm_data);
261 #else	/* HAVE_IFM_DATA */
262 				ift->ifa_data = NULL;
263 #endif	/* HAVE_IFM_DATA */
264 
265 				ift = (ift->ifa_next = ift + 1);
266 			} else
267 				index = 0;
268 			break;
269 
270 		case RTM_NEWADDR:
271 			ifam = (struct ifa_msghdr *)rtm;
272 			if (index && ifam->ifam_index != index)
273 				abort();	/* this cannot happen */
274 
275 			if (index == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
276 				break;
277 			ift->ifa_name = cif->ifa_name;
278 			ift->ifa_flags = cif->ifa_flags;
279 			ift->ifa_data = NULL;
280 			p = (char *)(ifam + 1);
281 			/* Scan to look for length of address */
282 			alen = 0;
283 			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
284 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
285 				    == 0)
286 					continue;
287 				sa = (struct sockaddr *)p;
288 				len = SA_RLEN(sa);
289 				if (i == RTAX_IFA) {
290 					alen = len;
291 					break;
292 				}
293 				p += len;
294 			}
295 			for (p = p0, i = 0; i < RTAX_MAX; i++) {
296 				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
297 				    == 0)
298 					continue;
299 				sa = (struct sockaddr *)p;
300 				len = SA_RLEN(sa);
301 				switch (i) {
302 				case RTAX_IFA:
303 					ift->ifa_addr = (struct sockaddr *)data;
304 					memcpy(data, p, len);
305 					data += len;
306 					break;
307 
308 				case RTAX_NETMASK:
309 					ift->ifa_netmask =
310 					    (struct sockaddr *)data;
311 					if (SA_LEN(sa) == 0) {
312 						memset(data, 0, alen);
313 						data += alen;
314 						break;
315 					}
316 					memcpy(data, p, len);
317 					data += len;
318 					break;
319 
320 				case RTAX_BRD:
321 					ift->ifa_broadaddr =
322 					    (struct sockaddr *)data;
323 					memcpy(data, p, len);
324 					data += len;
325 					break;
326 				}
327 				p += len;
328 			}
329 
330 #ifdef	HAVE_IFAM_DATA
331 			/* ifam_data needs to be aligned */
332 			ift->ifa_data = data = (void *)ALIGN(data);
333 			memcpy(data, &ifam->ifam_data, sizeof(ifam->ifam_data));
334 			data += sizeof(ifam->ifam_data);
335 #endif	/* HAVE_IFAM_DATA */
336 
337 			ift = (ift->ifa_next = ift + 1);
338 			break;
339 		}
340 	}
341 
342 	free(buf);
343 #else	/* NET_RT_IFLIST */
344 	ifr = ifc.ifc_req;
345 	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
346 
347 	while (ifr < lifr) {
348 		struct sockaddr *sa;
349 
350 		ift->ifa_name = names;
351 		names[sizeof(ifr->ifr_name)] = 0;
352 		strncpy(names, ifr->ifr_name, sizeof(ifr->ifr_name));
353 		while (*names++)
354 			;
355 
356 		ift->ifa_addr = (struct sockaddr *)data;
357 		sa = &ifr->ifr_addr;
358 		memcpy(data, sa, SA_LEN(sa));
359 		data += SA_RLEN(sa);
360 
361 		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
362 		ift = (ift->ifa_next = ift + 1);
363 	}
364 #endif	/* NET_RT_IFLIST */
365 	if (--ift >= ifa) {
366 		ift->ifa_next = NULL;
367 		*pif = ifa;
368 	} else {
369 		*pif = NULL;
370 		free(ifa);
371 	}
372 	return (0);
373 }
374 
375 void
376 freeifaddrs(struct ifaddrs *ifp)
377 {
378 	free(ifp);
379 }
380