getifaddrs.c revision 1.12 
1/*	$NetBSD: getifaddrs.c,v 1.12 2009/04/27 20:10:49 dyoung 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 1.12 2009/04/27 20:10:49 dyoung 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#include <sys/param.h>
39#include <net/route.h>
40#include <sys/sysctl.h>
41#include <net/if_dl.h>
42
43#include <assert.h>
44#include <errno.h>
45#include <ifaddrs.h>
46#include <stdlib.h>
47#include <string.h>
48
49#ifdef __weak_alias
50__weak_alias(getifaddrs,_getifaddrs)
51__weak_alias(freeifaddrs,_freeifaddrs)
52#endif
53
54#define	SALIGN	(sizeof(long) - 1)
55#define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
56
57int
58getifaddrs(struct ifaddrs **pif)
59{
60	int icnt = 1;
61	int dcnt = 0;
62	int ncnt = 0;
63	int mib[6];
64	size_t needed;
65	char *buf;
66	char *next;
67	struct ifaddrs cif;
68	char *p, *p0;
69	struct rt_msghdr *rtm;
70	struct if_msghdr *ifm;
71	struct ifa_msghdr *ifam;
72	struct sockaddr *sa;
73	struct ifaddrs *ifa, *ift;
74	u_short idx = 0;
75	int i;
76	size_t len, alen;
77	char *data;
78	char *names;
79
80	_DIAGASSERT(pif != NULL);
81
82	mib[0] = CTL_NET;
83	mib[1] = PF_ROUTE;
84	mib[2] = 0;             /* protocol */
85	mib[3] = 0;             /* wildcard address family */
86	mib[4] = NET_RT_IFLIST;
87	mib[5] = 0;             /* no flags */
88	if (sysctl(mib, __arraycount(mib), NULL, &needed, NULL, 0) < 0)
89		return (-1);
90	if ((buf = malloc(needed)) == NULL)
91		return (-1);
92	if (sysctl(mib, __arraycount(mib), buf, &needed, NULL, 0) < 0) {
93		free(buf);
94		return (-1);
95	}
96
97	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
98		rtm = (struct rt_msghdr *)(void *)next;
99		if (rtm->rtm_version != RTM_VERSION)
100			continue;
101		switch (rtm->rtm_type) {
102		case RTM_IFINFO:
103			ifm = (struct if_msghdr *)(void *)rtm;
104			if (ifm->ifm_addrs & RTA_IFP) {
105				const struct sockaddr_dl *dl;
106
107				idx = ifm->ifm_index;
108				++icnt;
109				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
110				dcnt += SA_RLEN((const struct sockaddr *)(const void *)dl) +
111				    ALIGNBYTES;
112				dcnt += sizeof(ifm->ifm_data);
113				ncnt += dl->sdl_nlen + 1;
114			} else
115				idx = 0;
116			break;
117
118		case RTM_NEWADDR:
119			ifam = (struct ifa_msghdr *)(void *)rtm;
120			if (idx && ifam->ifam_index != idx)
121				abort();	/* this cannot happen */
122
123#define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
124			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
125				break;
126			p = (char *)(void *)(ifam + 1);
127			++icnt;
128			/* Scan to look for length of address */
129			alen = 0;
130			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
131				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
132				    == 0)
133					continue;
134				sa = (struct sockaddr *)(void *)p;
135				len = SA_RLEN(sa);
136				if (i == RTAX_IFA) {
137					alen = len;
138					break;
139				}
140				p += len;
141			}
142			for (p = p0, i = 0; i < RTAX_MAX; i++) {
143				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
144				    == 0)
145					continue;
146				sa = (struct sockaddr *)(void *)p;
147				len = SA_RLEN(sa);
148				if (i == RTAX_NETMASK && sa->sa_len == 0)
149					dcnt += alen;
150				else
151					dcnt += len;
152				p += len;
153			}
154			break;
155		}
156	}
157
158	if (icnt + dcnt + ncnt == 1) {
159		*pif = NULL;
160		free(buf);
161		return (0);
162	}
163	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
164	if (data == NULL) {
165		free(buf);
166		return(-1);
167	}
168
169	ifa = (struct ifaddrs *)(void *)data;
170	data += sizeof(struct ifaddrs) * icnt;
171	names = data + dcnt;
172
173	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
174	ift = ifa;
175
176	idx = 0;
177	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
178		rtm = (struct rt_msghdr *)(void *)next;
179		if (rtm->rtm_version != RTM_VERSION)
180			continue;
181		switch (rtm->rtm_type) {
182		case RTM_IFINFO:
183			ifm = (struct if_msghdr *)(void *)rtm;
184			if (ifm->ifm_addrs & RTA_IFP) {
185				const struct sockaddr_dl *dl;
186
187				idx = ifm->ifm_index;
188				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
189
190				memset(&cif, 0, sizeof(cif));
191
192				cif.ifa_name = names;
193				cif.ifa_flags = (int)ifm->ifm_flags;
194				memcpy(names, dl->sdl_data,
195				    (size_t)dl->sdl_nlen);
196				names[dl->sdl_nlen] = 0;
197				names += dl->sdl_nlen + 1;
198
199				cif.ifa_addr = (struct sockaddr *)(void *)data;
200				memcpy(data, dl, (size_t)dl->sdl_len);
201				data += SA_RLEN((const struct sockaddr *)(const void *)dl);
202
203				/* ifm_data needs to be aligned */
204				cif.ifa_data = data = (void *)ALIGN(data);
205				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
206 				data += sizeof(ifm->ifm_data);
207			} else
208				idx = 0;
209			break;
210
211		case RTM_NEWADDR:
212			ifam = (struct ifa_msghdr *)(void *)rtm;
213			if (idx && ifam->ifam_index != idx)
214				abort();	/* this cannot happen */
215
216			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
217				break;
218			ift->ifa_name = cif.ifa_name;
219			ift->ifa_flags = cif.ifa_flags;
220			ift->ifa_data = NULL;
221			p = (char *)(void *)(ifam + 1);
222			/* Scan to look for length of address */
223			alen = 0;
224			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
225				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
226				    == 0)
227					continue;
228				sa = (struct sockaddr *)(void *)p;
229				len = SA_RLEN(sa);
230				if (i == RTAX_IFA) {
231					alen = len;
232					break;
233				}
234				p += len;
235			}
236			for (p = p0, i = 0; i < RTAX_MAX; i++) {
237				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
238				    == 0)
239					continue;
240				sa = (struct sockaddr *)(void *)p;
241				len = SA_RLEN(sa);
242				switch (i) {
243				case RTAX_IFA:
244					ift->ifa_addr =
245					    (struct sockaddr *)(void *)data;
246					memcpy(data, p, len);
247					data += len;
248					if (ift->ifa_addr->sa_family == AF_LINK)
249						ift->ifa_data = cif.ifa_data;
250					break;
251
252				case RTAX_NETMASK:
253					ift->ifa_netmask =
254					    (struct sockaddr *)(void *)data;
255					if (sa->sa_len == 0) {
256						memset(data, 0, alen);
257						data += alen;
258						break;
259					}
260					memcpy(data, p, len);
261					data += len;
262					break;
263
264				case RTAX_BRD:
265					ift->ifa_broadaddr =
266					    (struct sockaddr *)(void *)data;
267					memcpy(data, p, len);
268					data += len;
269					break;
270				}
271				p += len;
272			}
273
274
275			ift = (ift->ifa_next = ift + 1);
276			break;
277		}
278	}
279
280	free(buf);
281	if (--ift >= ifa) {
282		ift->ifa_next = NULL;
283		*pif = ifa;
284	} else {
285		*pif = NULL;
286		free(ifa);
287	}
288	return (0);
289}
290
291void
292freeifaddrs(struct ifaddrs *ifp)
293{
294
295	_DIAGASSERT(ifp != NULL);
296
297	free(ifp);
298}
299