1 /* $FreeBSD: src/lib/libc/net/getifaddrs.c,v 1.6 2002/07/25 08:08:30 ume Exp $ */
2 /* $KAME: getifaddrs.c,v 1.9 2001/08/20 02:31:20 itojun Exp $ */
3
4 /*
5 * Copyright (c) 1995, 1999
6 * Berkeley Software Design, Inc. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``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 Berkeley Software Design, Inc. 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 * BSDI getifaddrs.c,v 2.12 2000/02/23 14:51:59 dab Exp
27 */
28 /*
29 * NOTE: SIOCGIFCONF case is not LP64 friendly. it also does not perform
30 * try-and-error for region size.
31 */
32 #include "namespace.h"
33 #include <sys/types.h>
34 #include <sys/ioctl.h>
35 #include <sys/socket.h>
36 #include <net/if.h>
37 #include <sys/param.h>
38 #include <net/route.h>
39 #include <sys/sysctl.h>
40 #include <net/if_dl.h>
41
42 #include <errno.h>
43 #include <ifaddrs.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include "un-namespace.h"
47
48 #if !defined(AF_LINK)
49 #define SA_LEN(sa) sizeof(struct sockaddr)
50 #endif
51
52 #if !defined(SA_LEN)
53 #define SA_LEN(sa) (sa)->sa_len
54 #endif
55
56 #define SA_RLEN(sa) RT_ROUNDUP((sa)->sa_len)
57
58 #ifndef ALIGNBYTES
59 /*
60 * On systems with a routing socket, ALIGNBYTES should match the value
61 * that the kernel uses when building the messages.
62 */
63 #define ALIGNBYTES XXX
64 #endif
65 #ifndef ALIGN
66 #define ALIGN(p) (((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
67 #endif
68
69 #define MAX_SYSCTL_TRY 5
70
71 int
getifaddrs(struct ifaddrs ** pif)72 getifaddrs(struct ifaddrs **pif)
73 {
74 int icnt = 1;
75 int dcnt = 0;
76 int ncnt = 0;
77 int ntry = 0;
78 int mib[6];
79 size_t needed;
80 char *buf;
81 char *next;
82 struct ifaddrs *cif = NULL;
83 char *p, *p0;
84 struct rt_msghdr *rtm;
85 struct if_msghdr *ifm;
86 struct ifa_msghdr *ifam;
87 struct sockaddr_dl *dl;
88 struct sockaddr *sa;
89 struct ifaddrs *ifa, *ift;
90 u_short idx = 0;
91 int i;
92 size_t len, alen;
93 char *data;
94 char *names;
95
96 mib[0] = CTL_NET;
97 mib[1] = PF_ROUTE;
98 mib[2] = 0; /* protocol */
99 mib[3] = 0; /* wildcard address family */
100 mib[4] = NET_RT_IFLIST;
101 mib[5] = 0; /* no flags */
102 do {
103 /*
104 * We'll try to get addresses several times in case that
105 * the number of addresses is unexpectedly increased during
106 * the two sysctl calls. This should rarely happen, but we'll
107 * try to do our best for applications that assume success of
108 * this library (which should usually be the case).
109 * Portability note: since FreeBSD does not add margin of
110 * memory at the first sysctl, the possibility of failure on
111 * the second sysctl call is a bit higher.
112 */
113
114 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
115 return (-1);
116 if ((buf = malloc(needed)) == NULL)
117 return (-1);
118 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
119 if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
120 free(buf);
121 return (-1);
122 }
123 free(buf);
124 buf = NULL;
125 }
126 } while (buf == NULL);
127
128 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
129 rtm = (struct rt_msghdr *)(void *)next;
130 if (rtm->rtm_version != RTM_VERSION)
131 continue;
132 switch (rtm->rtm_type) {
133 case RTM_IFINFO:
134 ifm = (struct if_msghdr *)(void *)rtm;
135 if (ifm->ifm_addrs & RTA_IFP) {
136 idx = ifm->ifm_index;
137 ++icnt;
138 dl = (struct sockaddr_dl *)(void *)(ifm + 1);
139 dcnt += SA_RLEN((struct sockaddr *)(void*)dl) +
140 ALIGNBYTES;
141 dcnt += sizeof(ifm->ifm_data);
142 ncnt += dl->sdl_nlen + 1;
143 } else
144 idx = 0;
145 break;
146
147 case RTM_NEWADDR:
148 ifam = (struct ifa_msghdr *)(void *)rtm;
149 if (idx && ifam->ifam_index != idx)
150 abort(); /* this cannot happen */
151
152 #define RTA_MASKS (RTA_NETMASK | RTA_IFA | RTA_BRD)
153 if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
154 break;
155 p = (char *)(void *)(ifam + 1);
156 ++icnt;
157 /* Scan to look for length of address */
158 alen = 0;
159 for (p0 = p, i = 0; i < RTAX_MAX; i++) {
160 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
161 == 0)
162 continue;
163 sa = (struct sockaddr *)(void *)p;
164 len = SA_RLEN(sa);
165 if (i == RTAX_IFA) {
166 alen = len;
167 break;
168 }
169 p += len;
170 }
171 for (p = p0, i = 0; i < RTAX_MAX; i++) {
172 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
173 == 0)
174 continue;
175 sa = (struct sockaddr *)(void *)p;
176 len = SA_RLEN(sa);
177 if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
178 dcnt += alen;
179 else
180 dcnt += len;
181 p += len;
182 }
183 break;
184 }
185 }
186
187 if (icnt + dcnt + ncnt == 1) {
188 *pif = NULL;
189 free(buf);
190 return (0);
191 }
192 data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
193 if (data == NULL) {
194 free(buf);
195 return(-1);
196 }
197
198 ifa = (struct ifaddrs *)(void *)data;
199 data += sizeof(struct ifaddrs) * icnt;
200 names = data + dcnt;
201
202 memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
203 ift = ifa;
204
205 idx = 0;
206 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
207 rtm = (struct rt_msghdr *)(void *)next;
208 if (rtm->rtm_version != RTM_VERSION)
209 continue;
210 switch (rtm->rtm_type) {
211 case RTM_IFINFO:
212 ifm = (struct if_msghdr *)(void *)rtm;
213 if (ifm->ifm_addrs & RTA_IFP) {
214 idx = ifm->ifm_index;
215 dl = (struct sockaddr_dl *)(void *)(ifm + 1);
216
217 cif = ift;
218 ift->ifa_name = names;
219 ift->ifa_flags = (int)ifm->ifm_flags;
220 memcpy(names, dl->sdl_data,
221 (size_t)dl->sdl_nlen);
222 names[dl->sdl_nlen] = 0;
223 names += dl->sdl_nlen + 1;
224
225 ift->ifa_addr = (struct sockaddr *)(void *)data;
226 memcpy(data, dl,
227 (size_t)SA_LEN((struct sockaddr *)
228 (void *)dl));
229 data += SA_RLEN((struct sockaddr *)(void *)dl);
230
231 /* ifm_data needs to be aligned */
232 ift->ifa_data = data = (void *)ALIGN(data);
233 memcpy(data, &ifm->ifm_data, sizeof(ifm->ifm_data));
234 data += sizeof(ifm->ifm_data);
235 ift = (ift->ifa_next = ift + 1);
236 } else
237 idx = 0;
238 break;
239
240 case RTM_NEWADDR:
241 ifam = (struct ifa_msghdr *)(void *)rtm;
242 if (idx && ifam->ifam_index != idx)
243 abort(); /* this cannot happen */
244
245 if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
246 break;
247 ift->ifa_name = cif->ifa_name;
248 ift->ifa_flags = cif->ifa_flags;
249 ift->ifa_data = NULL;
250 ift->ifa_addrflags = ifam->ifam_addrflags;
251 p = (char *)(void *)(ifam + 1);
252 /* Scan to look for length of address */
253 alen = 0;
254 for (p0 = p, i = 0; i < RTAX_MAX; i++) {
255 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
256 == 0)
257 continue;
258 sa = (struct sockaddr *)(void *)p;
259 len = SA_RLEN(sa);
260 if (i == RTAX_IFA) {
261 alen = len;
262 break;
263 }
264 p += len;
265 }
266 for (p = p0, i = 0; i < RTAX_MAX; i++) {
267 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
268 == 0)
269 continue;
270 sa = (struct sockaddr *)(void *)p;
271 len = SA_RLEN(sa);
272 switch (i) {
273 case RTAX_IFA:
274 ift->ifa_addr =
275 (struct sockaddr *)(void *)data;
276 memcpy(data, p, len);
277 data += len;
278 break;
279
280 case RTAX_NETMASK:
281 ift->ifa_netmask =
282 (struct sockaddr *)(void *)data;
283 if (SA_LEN(sa) == 0) {
284 memset(data, 0, alen);
285 data += alen;
286 break;
287 }
288 memcpy(data, p, len);
289 data += len;
290 break;
291
292 case RTAX_BRD:
293 ift->ifa_broadaddr =
294 (struct sockaddr *)(void *)data;
295 memcpy(data, p, len);
296 data += len;
297 break;
298 }
299 p += len;
300 }
301
302 ift = (ift->ifa_next = ift + 1);
303 break;
304 }
305 }
306
307 free(buf);
308 if (--ift >= ifa) {
309 ift->ifa_next = NULL;
310 *pif = ifa;
311 } else {
312 *pif = NULL;
313 free(ifa);
314 }
315 return (0);
316 }
317
318 void
freeifaddrs(struct ifaddrs * ifp)319 freeifaddrs(struct ifaddrs *ifp)
320 {
321
322 free(ifp);
323 }
324