xref: /freebsd/lib/libc/net/getifmaddrs.c (revision 640235e2c2ba32947f7c59d168437ffa1280f1e6)
1 /*
2  * Copyright (c) 2003 Bruce M. Simpson.
3  * All rights reserved
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "namespace.h"
31 #include <sys/param.h>
32 #include <sys/sysctl.h>
33 #include <sys/ioctl.h>
34 #include <sys/socket.h>
35 #include <net/if.h>
36 #include <net/if_dl.h>
37 #include <net/route.h>
38 
39 #include <errno.h>
40 #include <ifaddrs.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include "un-namespace.h"
44 
45 #define	SALIGN	(sizeof(long) - 1)
46 #define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : \
47 			    (SALIGN + 1))
48 #define	MAX_SYSCTL_TRY	5
49 #define	RTA_MASKS	(RTA_GATEWAY | RTA_IFP | RTA_IFA)
50 
51 int
52 getifmaddrs(struct ifmaddrs **pif)
53 {
54 	int icnt = 1;
55 	int dcnt = 0;
56 	int ntry = 0;
57 	size_t len;
58 	size_t needed;
59 	int mib[6];
60 	int i;
61 	char *buf;
62 	char *data;
63 	char *next;
64 	char *p;
65 	struct ifma_msghdr *ifmam;
66 	struct ifmaddrs *ifa, *ift;
67 	struct rt_msghdr *rtm;
68 	struct sockaddr *sa;
69 
70 	mib[0] = CTL_NET;
71 	mib[1] = PF_ROUTE;
72 	mib[2] = 0;             /* protocol */
73 	mib[3] = 0;             /* wildcard address family */
74 	mib[4] = NET_RT_IFMALIST;
75 	mib[5] = 0;             /* no flags */
76 	do {
77 		if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
78 			return (-1);
79 		if ((buf = malloc(needed)) == NULL)
80 			return (-1);
81 		if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
82 			if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
83 				free(buf);
84 				return (-1);
85 			}
86 			free(buf);
87 			buf = NULL;
88 		}
89 	} while (buf == NULL);
90 
91 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
92 		rtm = (struct rt_msghdr *)(void *)next;
93 		if (rtm->rtm_version != RTM_VERSION)
94 			continue;
95 		switch (rtm->rtm_type) {
96 		case RTM_NEWMADDR:
97 			ifmam = (struct ifma_msghdr *)(void *)rtm;
98 			if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
99 				break;
100 			icnt++;
101 			p = (char *)(ifmam + 1);
102 			for (i = 0; i < RTAX_MAX; i++) {
103 				if ((RTA_MASKS & ifmam->ifmam_addrs &
104 				    (1 << i)) == 0)
105 					continue;
106 				sa = (struct sockaddr *)(void *)p;
107 				len = SA_RLEN(sa);
108 				dcnt += len;
109 				p += len;
110 			}
111 			break;
112 		}
113 	}
114 
115 	data = malloc(sizeof(struct ifmaddrs) * icnt + dcnt);
116 	if (data == NULL) {
117 		free(buf);
118 		return (-1);
119 	}
120 
121 	ifa = (struct ifmaddrs *)(void *)data;
122 	data += sizeof(struct ifmaddrs) * icnt;
123 
124 	memset(ifa, 0, sizeof(struct ifmaddrs) * icnt);
125 	ift = ifa;
126 
127 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
128 		rtm = (struct rt_msghdr *)(void *)next;
129 		if (rtm->rtm_version != RTM_VERSION)
130 			continue;
131 
132 		switch (rtm->rtm_type) {
133 		case RTM_NEWMADDR:
134 			ifmam = (struct ifma_msghdr *)(void *)rtm;
135 			if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
136 				break;
137 
138 			p = (char *)(ifmam + 1);
139 			for (i = 0; i < RTAX_MAX; i++) {
140 				if ((RTA_MASKS & ifmam->ifmam_addrs &
141 				    (1 << i)) == 0)
142 					continue;
143 				sa = (struct sockaddr *)(void *)p;
144 				len = SA_RLEN(sa);
145 				switch (i) {
146 				case RTAX_GATEWAY:
147 					ift->ifma_lladdr =
148 					    (struct sockaddr *)(void *)data;
149 					memcpy(data, p, len);
150 					data += len;
151 					break;
152 
153 				case RTAX_IFP:
154 					ift->ifma_name =
155 					    (struct sockaddr *)(void *)data;
156 					memcpy(data, p, len);
157 					data += len;
158 					break;
159 
160 				case RTAX_IFA:
161 					ift->ifma_addr =
162 					    (struct sockaddr *)(void *)data;
163 					memcpy(data, p, len);
164 					data += len;
165 					break;
166 
167 				default:
168 					data += len;
169 					break;
170 				}
171 				p += len;
172 			}
173 			ift->ifma_next = ift + 1;
174 			ift = ift->ifma_next;
175 			break;
176 		}
177 	}
178 
179 	free(buf);
180 
181 	if (ift > ifa) {
182 		ift--;
183 		ift->ifma_next = NULL;
184 		*pif = ifa;
185 	} else {
186 		*pif = NULL;
187 		free(ifa);
188 	}
189 	return (0);
190 }
191 
192 void
193 freeifmaddrs(struct ifmaddrs *ifmp)
194 {
195 
196 	free(ifmp);
197 }
198