1 /* $KAME: getifaddrs.c,v 1.9 2001/08/20 02:31:20 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 * NOTE: SIOCGIFCONF case is not LP64 friendly. it also does not perform
29 * try-and-error for region size.
30 */
31
32 #include <sys/cdefs.h>
33 #ifndef FSTACK
34 __FBSDID("$FreeBSD$");
35
36 #include "namespace.h"
37 #endif
38 #include <sys/types.h>
39 #include <sys/ioctl.h>
40 #include <sys/socket.h>
41 #include <net/if.h>
42 #ifdef NET_RT_IFLIST
43 #include <sys/param.h>
44 #include <net/route.h>
45 #include <sys/sysctl.h>
46 #include <net/if_dl.h>
47 #endif
48
49 #include <errno.h>
50 #include <ifaddrs.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #ifndef FSTACK
54 #include "un-namespace.h"
55 #endif
56
57 #if !defined(AF_LINK)
58 #define SA_LEN(sa) sizeof(struct sockaddr)
59 #endif
60
61 #if !defined(SA_LEN)
62 #define SA_LEN(sa) (sa)->sa_len
63 #endif
64
65 #define SALIGN (sizeof(long) - 1)
66 #define SA_RLEN(sa) ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : (SALIGN + 1))
67
68 #ifndef ALIGNBYTES
69 /*
70 * On systems with a routing socket, ALIGNBYTES should match the value
71 * that the kernel uses when building the messages.
72 */
73 #define ALIGNBYTES (sizeof(long long) - 1)
74 #endif
75 #ifndef ALIGN
76 #define ALIGN(p) (((u_long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
77 #endif
78
79 #define MAX_SYSCTL_TRY 5
80
81 int
getifaddrs(struct ifaddrs ** pif)82 getifaddrs(struct ifaddrs **pif)
83 {
84 int icnt = 1;
85 int dcnt = 0;
86 int ncnt = 0;
87 int ntry = 0;
88 int mib[6];
89 size_t needed;
90 char *buf;
91 char *next;
92 struct ifaddrs *cif;
93 char *p, *p0;
94 struct rt_msghdr *rtm;
95 struct if_msghdrl *ifm;
96 struct ifa_msghdrl *ifam;
97 struct sockaddr_dl *dl;
98 struct sockaddr *sa;
99 struct ifaddrs *ifa, *ift;
100 struct if_data *if_data;
101 u_short idx = 0;
102 int i;
103 size_t len, alen;
104 char *data;
105 char *names;
106
107 mib[0] = CTL_NET;
108 mib[1] = PF_ROUTE;
109 mib[2] = 0; /* protocol */
110 mib[3] = 0; /* wildcard address family */
111 mib[4] = NET_RT_IFLISTL;/* extra fields for extensible msghdr structs */
112 mib[5] = 0; /* no flags */
113 do {
114 /*
115 * We'll try to get addresses several times in case that
116 * the number of addresses is unexpectedly increased during
117 * the two sysctl calls. This should rarely happen, but we'll
118 * try to do our best for applications that assume success of
119 * this library (which should usually be the case).
120 * Portability note: since FreeBSD does not add margin of
121 * memory at the first sysctl, the possibility of failure on
122 * the second sysctl call is a bit higher.
123 */
124
125 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
126 return (-1);
127 if ((buf = malloc(needed)) == NULL)
128 return (-1);
129 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
130 if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
131 free(buf);
132 return (-1);
133 }
134 free(buf);
135 buf = NULL;
136 }
137 } while (buf == NULL);
138
139 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
140 rtm = (struct rt_msghdr *)(void *)next;
141 if (rtm->rtm_version != RTM_VERSION)
142 continue;
143 switch (rtm->rtm_type) {
144 case RTM_IFINFO:
145 ifm = (struct if_msghdrl *)(void *)rtm;
146 if (ifm->ifm_addrs & RTA_IFP) {
147 idx = ifm->ifm_index;
148 ++icnt;
149 if_data = IF_MSGHDRL_IFM_DATA(ifm);
150 dcnt += if_data->ifi_datalen;
151 dl = (struct sockaddr_dl *)IF_MSGHDRL_RTA(ifm);
152 dcnt += SA_RLEN((struct sockaddr *)(void*)dl) +
153 ALIGNBYTES;
154 ncnt += dl->sdl_nlen + 1;
155 } else
156 idx = 0;
157 break;
158
159 case RTM_NEWADDR:
160 ifam = (struct ifa_msghdrl *)(void *)rtm;
161 if (idx && ifam->ifam_index != idx)
162 abort(); /* this cannot happen */
163
164 #define RTA_MASKS (RTA_NETMASK | RTA_IFA | RTA_BRD)
165 if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
166 break;
167 p = (char *)IFA_MSGHDRL_RTA(ifam);
168 ++icnt;
169 if_data = IFA_MSGHDRL_IFAM_DATA(ifam);
170 dcnt += if_data->ifi_datalen + ALIGNBYTES;
171
172 /* Scan to look for length of address */
173 alen = 0;
174 for (p0 = p, i = 0; i < RTAX_MAX; i++) {
175 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
176 == 0)
177 continue;
178 sa = (struct sockaddr *)(void *)p;
179 len = SA_RLEN(sa);
180 if (i == RTAX_IFA) {
181 alen = len;
182 break;
183 }
184 p += len;
185 }
186 for (p = p0, i = 0; i < RTAX_MAX; i++) {
187 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
188 == 0)
189 continue;
190 sa = (struct sockaddr *)(void *)p;
191 len = SA_RLEN(sa);
192 if (i == RTAX_NETMASK && SA_LEN(sa) == 0)
193 dcnt += alen;
194 else
195 dcnt += len;
196 p += len;
197 }
198 break;
199 }
200 }
201
202 if (icnt + dcnt + ncnt == 1) {
203 *pif = NULL;
204 free(buf);
205 return (0);
206 }
207 data = malloc(sizeof(struct ifaddrs) * icnt + dcnt + ncnt);
208 if (data == NULL) {
209 free(buf);
210 return(-1);
211 }
212
213 ifa = (struct ifaddrs *)(void *)data;
214 data += sizeof(struct ifaddrs) * icnt;
215 names = data + dcnt;
216
217 memset(ifa, 0, sizeof(struct ifaddrs) * icnt);
218 ift = ifa;
219
220 idx = 0;
221 cif = NULL;
222 for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
223 rtm = (struct rt_msghdr *)(void *)next;
224 if (rtm->rtm_version != RTM_VERSION)
225 continue;
226 switch (rtm->rtm_type) {
227 case RTM_IFINFO:
228 ifm = (struct if_msghdrl *)(void *)rtm;
229 if ((ifm->ifm_addrs & RTA_IFP) == 0) {
230 idx = 0;
231 break;
232 }
233
234 idx = ifm->ifm_index;
235 dl = (struct sockaddr_dl *)IF_MSGHDRL_RTA(ifm);
236
237 cif = ift;
238 ift->ifa_name = names;
239 ift->ifa_flags = (int)ifm->ifm_flags;
240 memcpy(names, dl->sdl_data, (size_t)dl->sdl_nlen);
241 names[dl->sdl_nlen] = 0;
242 names += dl->sdl_nlen + 1;
243
244 ift->ifa_addr = (struct sockaddr *)(void *)data;
245 memcpy(data, dl, (size_t)SA_LEN((struct sockaddr *)
246 (void *)dl));
247 data += SA_RLEN((struct sockaddr *)(void *)dl);
248
249 if_data = IF_MSGHDRL_IFM_DATA(ifm);
250 /* ifm_data needs to be aligned */
251 ift->ifa_data = data = (void *)ALIGN(data);
252 memcpy(data, if_data, if_data->ifi_datalen);
253 data += if_data->ifi_datalen;
254
255 ift = (ift->ifa_next = ift + 1);
256 break;
257
258 case RTM_NEWADDR:
259 ifam = (struct ifa_msghdrl *)(void *)rtm;
260 if (idx && ifam->ifam_index != idx)
261 abort(); /* this cannot happen */
262
263 if (idx == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
264 break;
265 ift->ifa_name = cif->ifa_name;
266 ift->ifa_flags = cif->ifa_flags;
267 ift->ifa_data = NULL;
268
269 p = (char *)IFA_MSGHDRL_RTA(ifam);
270 /* Scan to look for length of address */
271 alen = 0;
272 for (p0 = p, i = 0; i < RTAX_MAX; i++) {
273 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
274 == 0)
275 continue;
276 sa = (struct sockaddr *)(void *)p;
277 len = SA_RLEN(sa);
278 if (i == RTAX_IFA) {
279 alen = len;
280 break;
281 }
282 p += len;
283 }
284 for (p = p0, i = 0; i < RTAX_MAX; i++) {
285 if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
286 == 0)
287 continue;
288 sa = (struct sockaddr *)(void *)p;
289 len = SA_RLEN(sa);
290 switch (i) {
291 case RTAX_IFA:
292 ift->ifa_addr =
293 (struct sockaddr *)(void *)data;
294 memcpy(data, p, len);
295 data += len;
296 break;
297
298 case RTAX_NETMASK:
299 ift->ifa_netmask =
300 (struct sockaddr *)(void *)data;
301 if (SA_LEN(sa) == 0) {
302 memset(data, 0, alen);
303 data += alen;
304 break;
305 }
306 memcpy(data, p, len);
307 data += len;
308 break;
309
310 case RTAX_BRD:
311 ift->ifa_broadaddr =
312 (struct sockaddr *)(void *)data;
313 memcpy(data, p, len);
314 data += len;
315 break;
316 }
317 p += len;
318 }
319
320 if_data = IFA_MSGHDRL_IFAM_DATA(ifam);
321 /* ifam_data needs to be aligned */
322 ift->ifa_data = data = (void *)ALIGN(data);
323 memcpy(data, if_data, if_data->ifi_datalen);
324 data += if_data->ifi_datalen;
325
326 ift = (ift->ifa_next = ift + 1);
327 break;
328 }
329 }
330
331 free(buf);
332
333 if (--ift >= ifa) {
334 ift->ifa_next = NULL;
335 *pif = ifa;
336 } else {
337 *pif = NULL;
338 free(ifa);
339 }
340 return (0);
341 }
342
343 void
freeifaddrs(struct ifaddrs * ifp)344 freeifaddrs(struct ifaddrs *ifp)
345 {
346
347 free(ifp);
348 }
349