getifaddrs.c revision 1.15 
1/*	$NetBSD: getifaddrs.c,v 1.15 2012/03/13 21:13:40 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 1.15 2012/03/13 21:13:40 christos Exp $");
31#endif /* LIBC_SCCS and not lint */
32
33#ifndef RUMP_ACTION
34#include "namespace.h"
35#endif
36#include <sys/types.h>
37#include <sys/ioctl.h>
38#include <sys/socket.h>
39#include <net/if.h>
40#include <sys/param.h>
41#include <net/route.h>
42#include <sys/sysctl.h>
43#include <net/if_dl.h>
44
45#include <assert.h>
46#include <errno.h>
47#include <ifaddrs.h>
48#include <stdlib.h>
49#include <string.h>
50
51#if defined(__weak_alias) && !defined(RUMP_ACTION)
52__weak_alias(getifaddrs,_getifaddrs)
53__weak_alias(freeifaddrs,_freeifaddrs)
54#endif
55
56#ifdef RUMP_ACTION
57#include <rump/rump_syscalls.h>
58#define sysctl(a,b,c,d,e,f) rump_sys___sysctl(a,b,c,d,e,f)
59#endif
60
61#define	SA_RLEN(sa)	RT_ROUNDUP((sa)->sa_len)
62
63int
64getifaddrs(struct ifaddrs **pif)
65{
66	size_t icnt = 1;
67	size_t dcnt = 0;
68	size_t ncnt = 0;
69	static const int mib[] = {
70		CTL_NET,
71		PF_ROUTE,
72		0,			/* protocol */
73		0,			/* wildcard address family */
74		NET_RT_IFLIST,
75		0			/* no flags */
76	};
77	size_t needed;
78	char *buf;
79	char *next;
80	struct ifaddrs cif;
81	char *p, *p0;
82	struct rt_msghdr *rtm;
83	struct if_msghdr *ifm;
84	struct ifa_msghdr *ifam;
85	struct sockaddr *sa;
86	struct ifaddrs *ifa, *ift;
87	u_short idx = 0;
88	int i;
89	size_t len, alen;
90	char *data;
91	char *names;
92
93	_DIAGASSERT(pif != NULL);
94
95	if (sysctl(mib, (u_int)__arraycount(mib), NULL, &needed, NULL, 0) < 0)
96		return (-1);
97	if ((buf = malloc(needed)) == NULL)
98		return (-1);
99	if (sysctl(mib, (u_int)__arraycount(mib), buf, &needed, NULL, 0) < 0) {
100		free(buf);
101		return (-1);
102	}
103
104	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
105		rtm = (struct rt_msghdr *)(void *)next;
106		if (rtm->rtm_version != RTM_VERSION)
107			continue;
108		switch (rtm->rtm_type) {
109		case RTM_IFINFO:
110			ifm = (struct if_msghdr *)(void *)rtm;
111			if (ifm->ifm_addrs & RTA_IFP) {
112				const struct sockaddr_dl *dl;
113
114				idx = ifm->ifm_index;
115				++icnt;
116				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
117				dcnt += SA_RLEN((const struct sockaddr *)(const void *)dl) +
118				    ALIGNBYTES;
119				dcnt += sizeof(ifm->ifm_data);
120				ncnt += dl->sdl_nlen + 1;
121			} else
122				idx = 0;
123			break;
124
125		case RTM_NEWADDR:
126			ifam = (struct ifa_msghdr *)(void *)rtm;
127			if (idx && ifam->ifam_index != idx)
128				abort();	/* this cannot happen */
129
130#define	RTA_MASKS	(RTA_NETMASK | RTA_IFA | RTA_BRD)
131			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
132				break;
133			p = (char *)(void *)(ifam + 1);
134			++icnt;
135			/* Scan to look for length of address */
136			alen = 0;
137			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
138				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
139				    == 0)
140					continue;
141				sa = (struct sockaddr *)(void *)p;
142				len = SA_RLEN(sa);
143				if (i == RTAX_IFA) {
144					alen = len;
145					break;
146				}
147				p += len;
148			}
149			for (p = p0, i = 0; i < RTAX_MAX; i++) {
150				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
151				    == 0)
152					continue;
153				sa = (struct sockaddr *)(void *)p;
154				len = SA_RLEN(sa);
155				if (i == RTAX_NETMASK && sa->sa_len == 0)
156					dcnt += alen;
157				else
158					dcnt += len;
159				p += len;
160			}
161			break;
162		}
163	}
164
165	if (icnt + dcnt + ncnt == 1) {
166		*pif = NULL;
167		free(buf);
168		return (0);
169	}
170	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
171	if (data == NULL) {
172		free(buf);
173		return(-1);
174	}
175
176	ifa = (struct ifaddrs *)(void *)data;
177	data += sizeof(struct ifaddrs) * icnt;
178	names = data + dcnt;
179
180	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
181	ift = ifa;
182
183	idx = 0;
184	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
185		rtm = (struct rt_msghdr *)(void *)next;
186		if (rtm->rtm_version != RTM_VERSION)
187			continue;
188		switch (rtm->rtm_type) {
189		case RTM_IFINFO:
190			ifm = (struct if_msghdr *)(void *)rtm;
191			if (ifm->ifm_addrs & RTA_IFP) {
192				const struct sockaddr_dl *dl;
193
194				idx = ifm->ifm_index;
195				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
196
197				memset(&cif, 0, sizeof(cif));
198
199				cif.ifa_name = names;
200				cif.ifa_flags = (int)ifm->ifm_flags;
201				memcpy(names, dl->sdl_data,
202				    (size_t)dl->sdl_nlen);
203				names[dl->sdl_nlen] = 0;
204				names += dl->sdl_nlen + 1;
205
206				cif.ifa_addr = (struct sockaddr *)(void *)data;
207				memcpy(data, dl, (size_t)dl->sdl_len);
208				data += SA_RLEN((const struct sockaddr *)(const void *)dl);
209
210				/* ifm_data needs to be aligned */
211				cif.ifa_data = data = (void *)ALIGN(data);
212				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
213 				data += sizeof(ifm->ifm_data);
214			} else
215				idx = 0;
216			break;
217
218		case RTM_NEWADDR:
219			ifam = (struct ifa_msghdr *)(void *)rtm;
220			if (idx && ifam->ifam_index != idx)
221				abort();	/* this cannot happen */
222
223			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
224				break;
225			ift->ifa_name = cif.ifa_name;
226			ift->ifa_flags = cif.ifa_flags;
227			ift->ifa_data = NULL;
228			p = (char *)(void *)(ifam + 1);
229			/* Scan to look for length of address */
230			alen = 0;
231			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
232				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
233				    == 0)
234					continue;
235				sa = (struct sockaddr *)(void *)p;
236				len = SA_RLEN(sa);
237				if (i == RTAX_IFA) {
238					alen = len;
239					break;
240				}
241				p += len;
242			}
243			for (p = p0, i = 0; i < RTAX_MAX; i++) {
244				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
245				    == 0)
246					continue;
247				sa = (struct sockaddr *)(void *)p;
248				len = SA_RLEN(sa);
249				switch (i) {
250				case RTAX_IFA:
251					ift->ifa_addr =
252					    (struct sockaddr *)(void *)data;
253					memcpy(data, p, len);
254					data += len;
255					if (ift->ifa_addr->sa_family == AF_LINK)
256						ift->ifa_data = cif.ifa_data;
257					break;
258
259				case RTAX_NETMASK:
260					ift->ifa_netmask =
261					    (struct sockaddr *)(void *)data;
262					if (sa->sa_len == 0) {
263						memset(data, 0, alen);
264						data += alen;
265						break;
266					}
267					memcpy(data, p, len);
268					data += len;
269					break;
270
271				case RTAX_BRD:
272					ift->ifa_broadaddr =
273					    (struct sockaddr *)(void *)data;
274					memcpy(data, p, len);
275					data += len;
276					break;
277				}
278				p += len;
279			}
280
281
282			ift = (ift->ifa_next = ift + 1);
283			break;
284		}
285	}
286
287	free(buf);
288	if (--ift >= ifa) {
289		ift->ifa_next = NULL;
290		*pif = ifa;
291	} else {
292		*pif = NULL;
293		free(ifa);
294	}
295	return (0);
296}
297
298void
299freeifaddrs(struct ifaddrs *ifp)
300{
301
302	_DIAGASSERT(ifp != NULL);
303
304	free(ifp);
305}
306