getifmaddrs.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2003 Bruce M. Simpson.
5 * 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 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/11/lib/libc/net/getifmaddrs.c 330897 2018-03-14 03:19:51Z eadler $");
31
32#include "namespace.h"
33#include <sys/param.h>
34#include <sys/sysctl.h>
35#include <sys/ioctl.h>
36#include <sys/socket.h>
37#include <net/if.h>
38#include <net/if_dl.h>
39#include <net/route.h>
40
41#include <errno.h>
42#include <ifaddrs.h>
43#include <stdlib.h>
44#include <string.h>
45#include "un-namespace.h"
46
47#define	SALIGN	(sizeof(long) - 1)
48#define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : \
49			    (SALIGN + 1))
50#define	MAX_SYSCTL_TRY	5
51#define	RTA_MASKS	(RTA_GATEWAY | RTA_IFP | RTA_IFA)
52
53int
54getifmaddrs(struct ifmaddrs **pif)
55{
56	int icnt = 1;
57	int dcnt = 0;
58	int ntry = 0;
59	size_t len;
60	size_t needed;
61	int mib[6];
62	int i;
63	char *buf;
64	char *data;
65	char *next;
66	char *p;
67	struct ifma_msghdr *ifmam;
68	struct ifmaddrs *ifa, *ift;
69	struct rt_msghdr *rtm;
70	struct sockaddr *sa;
71
72	mib[0] = CTL_NET;
73	mib[1] = PF_ROUTE;
74	mib[2] = 0;             /* protocol */
75	mib[3] = 0;             /* wildcard address family */
76	mib[4] = NET_RT_IFMALIST;
77	mib[5] = 0;             /* no flags */
78	do {
79		if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
80			return (-1);
81		if ((buf = malloc(needed)) == NULL)
82			return (-1);
83		if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
84			if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
85				free(buf);
86				return (-1);
87			}
88			free(buf);
89			buf = NULL;
90		}
91	} while (buf == NULL);
92
93	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
94		rtm = (struct rt_msghdr *)(void *)next;
95		if (rtm->rtm_version != RTM_VERSION)
96			continue;
97		switch (rtm->rtm_type) {
98		case RTM_NEWMADDR:
99			ifmam = (struct ifma_msghdr *)(void *)rtm;
100			if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
101				break;
102			icnt++;
103			p = (char *)(ifmam + 1);
104			for (i = 0; i < RTAX_MAX; i++) {
105				if ((RTA_MASKS & ifmam->ifmam_addrs &
106				    (1 << i)) == 0)
107					continue;
108				sa = (struct sockaddr *)(void *)p;
109				len = SA_RLEN(sa);
110				dcnt += len;
111				p += len;
112			}
113			break;
114		}
115	}
116
117	data = malloc(sizeof(struct ifmaddrs) * icnt + dcnt);
118	if (data == NULL) {
119		free(buf);
120		return (-1);
121	}
122
123	ifa = (struct ifmaddrs *)(void *)data;
124	data += sizeof(struct ifmaddrs) * icnt;
125
126	memset(ifa, 0, sizeof(struct ifmaddrs) * icnt);
127	ift = ifa;
128
129	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
130		rtm = (struct rt_msghdr *)(void *)next;
131		if (rtm->rtm_version != RTM_VERSION)
132			continue;
133
134		switch (rtm->rtm_type) {
135		case RTM_NEWMADDR:
136			ifmam = (struct ifma_msghdr *)(void *)rtm;
137			if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
138				break;
139
140			p = (char *)(ifmam + 1);
141			for (i = 0; i < RTAX_MAX; i++) {
142				if ((RTA_MASKS & ifmam->ifmam_addrs &
143				    (1 << i)) == 0)
144					continue;
145				sa = (struct sockaddr *)(void *)p;
146				len = SA_RLEN(sa);
147				switch (i) {
148				case RTAX_GATEWAY:
149					ift->ifma_lladdr =
150					    (struct sockaddr *)(void *)data;
151					memcpy(data, p, len);
152					data += len;
153					break;
154
155				case RTAX_IFP:
156					ift->ifma_name =
157					    (struct sockaddr *)(void *)data;
158					memcpy(data, p, len);
159					data += len;
160					break;
161
162				case RTAX_IFA:
163					ift->ifma_addr =
164					    (struct sockaddr *)(void *)data;
165					memcpy(data, p, len);
166					data += len;
167					break;
168
169				default:
170					data += len;
171					break;
172				}
173				p += len;
174			}
175			ift->ifma_next = ift + 1;
176			ift = ift->ifma_next;
177			break;
178		}
179	}
180
181	free(buf);
182
183	if (ift > ifa) {
184		ift--;
185		ift->ifma_next = NULL;
186		*pif = ifa;
187	} else {
188		*pif = NULL;
189		free(ifa);
190	}
191	return (0);
192}
193
194void
195freeifmaddrs(struct ifmaddrs *ifmp)
196{
197
198	free(ifmp);
199}
200