getifaddrs.c revision 1.8 
1/*	$NetBSD: getifaddrs.c,v 1.8 2001/08/20 02:33:49 itojun 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 1.8 2001/08/20 02:33:49 itojun 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
91int
92getifaddrs(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		if (SA_LEN(sa) < sizeof(*sa))
227			ifr = (struct ifreq *)(((char *)sa) + sizeof(*sa));
228		else
229			ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
230	}
231#endif	/* NET_RT_IFLIST */
232
233	if (icnt + dcnt + ncnt == 1) {
234		*pif = NULL;
235		free(buf);
236		return (0);
237	}
238	data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
239	if (data == NULL) {
240		free(buf);
241		return(-1);
242	}
243
244	ifa = (struct ifaddrs *)(void *)data;
245	data += sizeof(struct ifaddrs) * icnt;
246	names = data + dcnt;
247
248	memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
249	ift = ifa;
250
251#ifdef	NET_RT_IFLIST
252	idx = 0;
253	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
254		rtm = (struct rt_msghdr *)(void *)next;
255		if (rtm->rtm_version != RTM_VERSION)
256			continue;
257		switch (rtm->rtm_type) {
258		case RTM_IFINFO:
259			ifm = (struct if_msghdr *)(void *)rtm;
260			if (ifm->ifm_addrs & RTA_IFP) {
261				idx = ifm->ifm_index;
262				dl = (struct sockaddr_dl *)(void *)(ifm + 1);
263
264				cif = ift;
265				ift->ifa_name = names;
266				ift->ifa_flags = (int)ifm->ifm_flags;
267				memcpy(names, dl->sdl_data,
268				    (size_t)dl->sdl_nlen);
269				names[dl->sdl_nlen] = 0;
270				names += dl->sdl_nlen + 1;
271
272				ift->ifa_addr = (struct sockaddr *)(void *)data;
273				memcpy(data, dl,
274				    (size_t)SA_LEN((struct sockaddr *)
275				    (void *)dl));
276				data += SA_RLEN((struct sockaddr *)(void *)dl);
277
278#ifdef	HAVE_IFM_DATA
279				/* ifm_data needs to be aligned */
280				ift->ifa_data = data = (void *)ALIGN(data);
281				memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
282 				data += sizeof(ifm->ifm_data);
283#else	/* HAVE_IFM_DATA */
284				ift->ifa_data = NULL;
285#endif	/* HAVE_IFM_DATA */
286
287				ift = (ift->ifa_next = ift + 1);
288			} else
289				idx = 0;
290			break;
291
292		case RTM_NEWADDR:
293			ifam = (struct ifa_msghdr *)(void *)rtm;
294			if (idx && ifam->ifam_index != idx)
295				abort();	/* this cannot happen */
296
297			if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
298				break;
299			ift->ifa_name = cif->ifa_name;
300			ift->ifa_flags = cif->ifa_flags;
301			ift->ifa_data = NULL;
302			p = (char *)(void *)(ifam + 1);
303			/* Scan to look for length of address */
304			alen = 0;
305			for (p0 = p, i = 0; i < RTAX_MAX; i++) {
306				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
307				    == 0)
308					continue;
309				sa = (struct sockaddr *)(void *)p;
310				len = SA_RLEN(sa);
311				if (i == RTAX_IFA) {
312					alen = len;
313					break;
314				}
315				p += len;
316			}
317			for (p = p0, i = 0; i < RTAX_MAX; i++) {
318				if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
319				    == 0)
320					continue;
321				sa = (struct sockaddr *)(void *)p;
322				len = SA_RLEN(sa);
323				switch (i) {
324				case RTAX_IFA:
325					ift->ifa_addr =
326					    (struct sockaddr *)(void *)data;
327					memcpy(data, p, len);
328					data += len;
329					break;
330
331				case RTAX_NETMASK:
332					ift->ifa_netmask =
333					    (struct sockaddr *)(void *)data;
334					if (SA_LEN(sa) == 0) {
335						memset(data, 0, alen);
336						data += alen;
337						break;
338					}
339					memcpy(data, p, len);
340					data += len;
341					break;
342
343				case RTAX_BRD:
344					ift->ifa_broadaddr =
345					    (struct sockaddr *)(void *)data;
346					memcpy(data, p, len);
347					data += len;
348					break;
349				}
350				p += len;
351			}
352
353#ifdef	HAVE_IFAM_DATA
354			/* ifam_data needs to be aligned */
355			ift->ifa_data = data = (void *)ALIGN(data);
356			memcpy(data, &ifam->ifam_data, sizeof(ifam->ifam_data));
357			data += sizeof(ifam->ifam_data);
358#endif	/* HAVE_IFAM_DATA */
359
360			ift = (ift->ifa_next = ift + 1);
361			break;
362		}
363	}
364
365	free(buf);
366#else	/* NET_RT_IFLIST */
367	ifr = ifc.ifc_req;
368	lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
369
370	while (ifr < lifr) {
371		struct sockaddr *sa;
372
373		ift->ifa_name = names;
374		names[sizeof(ifr->ifr_name)] = 0;
375		strncpy(names, ifr->ifr_name, sizeof(ifr->ifr_name));
376		while (*names++)
377			;
378
379		ift->ifa_addr = (struct sockaddr *)data;
380		sa = &ifr->ifr_addr;
381		memcpy(data, sa, SA_LEN(sa));
382		data += SA_RLEN(sa);
383
384		ifr = (struct ifreq *)(((char *)sa) + SA_LEN(sa));
385		ift = (ift->ifa_next = ift + 1);
386	}
387#endif	/* NET_RT_IFLIST */
388	if (--ift >= ifa) {
389		ift->ifa_next = NULL;
390		*pif = ifa;
391	} else {
392		*pif = NULL;
393		free(ifa);
394	}
395	return (0);
396}
397
398void
399freeifaddrs(struct ifaddrs *ifp)
400{
401
402	_DIAGASSERT(ifp != NULL);
403
404	free(ifp);
405}
406