1 /* $NetBSD: if.c,v 1.29 2021/03/23 18:16:53 christos Exp $ */
2 /* $KAME: if.c,v 1.36 2004/11/30 22:32:01 suz Exp $ */
3
4 /*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * 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 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #define RTM_NAMES
34 #include <sys/param.h>
35 #include <sys/queue.h>
36 #include <sys/socket.h>
37 #include <sys/sysctl.h>
38 #include <sys/ioctl.h>
39 #include <net/if.h>
40 #include <net/if_types.h>
41 #include <ifaddrs.h>
42 #ifdef __FreeBSD__
43 #include <net/ethernet.h>
44 #else
45 #include <net/if_ether.h>
46 #endif
47 #include <net/route.h>
48 #include <net/if_dl.h>
49 #include <netinet/in.h>
50 #include <netinet/icmp6.h>
51 #include <unistd.h>
52 #include <errno.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <syslog.h>
56
57 #include "rtadvd.h"
58 #include "if.h"
59 #include "logit.h"
60 #include "prog_ops.h"
61
62 #ifndef RT_ROUNDUP
63 #define RT_ROUNDUP(a) \
64 ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
65 #define RT_ADVANCE(x, n) (x += RT_ROUNDUP((n)->sa_len))
66 #endif
67
68 static void
get_rtaddrs(int addrs,const struct sockaddr * sa,const struct sockaddr ** rti_info)69 get_rtaddrs(int addrs, const struct sockaddr *sa,
70 const struct sockaddr **rti_info)
71 {
72 int i;
73
74 for (i = 0; i < RTAX_MAX; i++) {
75 if (addrs & (1 << i)) {
76 rti_info[i] = sa;
77 RT_ADVANCE(sa, sa);
78 }
79 else
80 rti_info[i] = NULL;
81 }
82 }
83
84 struct sockaddr_dl *
if_nametosdl(const char * name)85 if_nametosdl(const char *name)
86 {
87 struct ifaddrs *ifap, *ifa;
88 struct sockaddr_dl *sdl;
89
90 if (getifaddrs(&ifap) != 0)
91 return (NULL);
92
93 for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
94 if (strcmp(ifa->ifa_name, name) != 0)
95 continue;
96 if (ifa->ifa_addr->sa_family != AF_LINK)
97 continue;
98
99 sdl = malloc(ifa->ifa_addr->sa_len);
100 if (!sdl)
101 continue; /*XXX*/
102
103 memcpy(sdl, ifa->ifa_addr, ifa->ifa_addr->sa_len);
104 freeifaddrs(ifap);
105 return (sdl);
106 }
107
108 freeifaddrs(ifap);
109 return (NULL);
110 }
111
112 int
if_getmtu(const char * name)113 if_getmtu(const char *name)
114 {
115 struct ifreq ifr;
116 int s, mtu;
117
118 if ((s = prog_socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
119 return 0;
120
121 memset(&ifr, 0, sizeof(ifr));
122 ifr.ifr_addr.sa_family = AF_INET6;
123 strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
124 if (prog_ioctl(s, SIOCGIFMTU, &ifr) != -1)
125 mtu = ifr.ifr_mtu;
126 else
127 mtu = 0;
128 prog_close(s);
129
130 return mtu;
131 }
132
133 /* give interface index and its old flags, then new flags returned */
134 int
if_getflags(unsigned int ifindex,int oifflags)135 if_getflags(unsigned int ifindex, int oifflags)
136 {
137 struct ifreq ifr;
138 int s;
139
140 if ((s = prog_socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
141 logit(LOG_ERR, "%s: socket: %m", __func__);
142 return (oifflags & ~IFF_UP);
143 }
144
145 memset(&ifr, 0, sizeof(ifr));
146 if_indextoname(ifindex, ifr.ifr_name);
147 if (prog_ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
148 logit(LOG_ERR, "%s: ioctl:SIOCGIFFLAGS: failed for %s",
149 __func__, ifr.ifr_name);
150 prog_close(s);
151 return (oifflags & ~IFF_UP);
152 }
153 prog_close(s);
154 return (ifr.ifr_flags);
155 }
156
157 #define ROUNDUP8(a) (1 + (((a) - 1) | 7))
158 int
lladdropt_length(struct sockaddr_dl * sdl)159 lladdropt_length(struct sockaddr_dl *sdl)
160 {
161 switch (sdl->sdl_type) {
162 case IFT_ETHER:
163 case IFT_FDDI:
164 return(ROUNDUP8(ETHER_ADDR_LEN + 2));
165 default:
166 return(0);
167 }
168 }
169
170 void
lladdropt_fill(struct sockaddr_dl * sdl,struct nd_opt_hdr * ndopt)171 lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
172 {
173 char *addr;
174
175 ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */
176
177 switch (sdl->sdl_type) {
178 case IFT_ETHER:
179 case IFT_FDDI:
180 ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
181 addr = (char *)(ndopt + 1);
182 memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
183 break;
184 default:
185 logit(LOG_ERR, "%s: unsupported link type(%d)",
186 __func__, sdl->sdl_type);
187 exit(1);
188 }
189
190 return;
191 }
192
193 #define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
194 #define SIN6(s) ((const struct sockaddr_in6 *)(s))
195 #define SDL(s) ((const struct sockaddr_dl *)(s))
196 char *
get_next_msg(char * buf,char * lim,unsigned int ifindex,size_t * lenp,int filter)197 get_next_msg(char *buf, char *lim, unsigned int ifindex, size_t *lenp,
198 int filter)
199 {
200 struct rt_msghdr *rtm;
201 struct ifa_msghdr *ifam;
202 const struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];
203
204 *lenp = 0;
205 for (rtm = (struct rt_msghdr *)buf;
206 rtm < (struct rt_msghdr *)lim;
207 rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
208 /* just for safety */
209 if (!rtm->rtm_msglen) {
210 logit(LOG_WARNING, "%s: rtm_msglen is 0 "
211 "(buf=%p lim=%p rtm=%p)", __func__,
212 buf, lim, rtm);
213 break;
214 }
215 if (FILTER_MATCH(rtm->rtm_type, filter) == 0) {
216 continue;
217 }
218
219 switch (rtm->rtm_type) {
220 case RTM_GET:
221 case RTM_ADD:
222 case RTM_DELETE:
223 /* address related checks */
224 sa = (struct sockaddr *)(rtm + 1);
225 get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
226 if ((dst = rti_info[RTAX_DST]) == NULL ||
227 dst->sa_family != AF_INET6)
228 continue;
229
230 if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
231 IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
232 continue;
233
234 if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
235 gw->sa_family != AF_LINK)
236 continue;
237 if (ifindex && SDL(gw)->sdl_index != ifindex)
238 continue;
239
240 if (rti_info[RTAX_NETMASK] == NULL)
241 continue;
242
243 /* found */
244 *lenp = rtm->rtm_msglen;
245 return (char *)rtm;
246 /* NOTREACHED */
247 case RTM_NEWADDR:
248 case RTM_DELADDR:
249 ifam = (struct ifa_msghdr *)rtm;
250
251 /* address related checks */
252 sa = (struct sockaddr *)(ifam + 1);
253 get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
254 if ((ifa = rti_info[RTAX_IFA]) == NULL ||
255 (ifa->sa_family != AF_INET &&
256 ifa->sa_family != AF_INET6))
257 continue;
258
259 if (ifa->sa_family == AF_INET6 &&
260 (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
261 IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
262 continue;
263
264 if (ifindex && ifam->ifam_index != ifindex)
265 continue;
266
267 /* found */
268 *lenp = ifam->ifam_msglen;
269 return (char *)rtm;
270 /* NOTREACHED */
271 #ifdef RTM_IFANNOUNCE
272 case RTM_IFANNOUNCE:
273 #endif
274 case RTM_IFINFO:
275 /* found */
276 *lenp = rtm->rtm_msglen;
277 return (char *)rtm;
278 /* NOTREACHED */
279 }
280 }
281
282 return (char *)rtm;
283 }
284 #undef FILTER_MATCH
285
286 const struct in6_addr *
get_addr(const void * buf)287 get_addr(const void *buf)
288 {
289 const struct rt_msghdr *rtm = buf;
290 const struct sockaddr *sa, *rti_info[RTAX_MAX];
291
292 sa = (const struct sockaddr *)(rtm + 1);
293 get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
294
295 return &SIN6(rti_info[RTAX_DST])->sin6_addr;
296 }
297
298 unsigned int
get_rtm_ifindex(const void * buf)299 get_rtm_ifindex(const void *buf)
300 {
301 const struct rt_msghdr *rtm = buf;
302 const struct sockaddr *sa, *rti_info[RTAX_MAX];
303
304 sa = (const struct sockaddr *)(rtm + 1);
305 get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
306
307 return SDL(rti_info[RTAX_GATEWAY])->sdl_index;
308 }
309
310 unsigned int
get_ifm_ifindex(const void * buf)311 get_ifm_ifindex(const void *buf)
312 {
313 const struct if_msghdr *ifm = buf;
314
315 return ifm->ifm_index;
316 }
317
318 unsigned int
get_ifam_ifindex(const void * buf)319 get_ifam_ifindex(const void *buf)
320 {
321 const struct ifa_msghdr *ifam = buf;
322
323 return ifam->ifam_index;
324 }
325
326 int
get_ifm_flags(const void * buf)327 get_ifm_flags(const void *buf)
328 {
329 const struct if_msghdr *ifm = buf;
330
331 return ifm->ifm_flags;
332 }
333
334 #ifdef RTM_IFANNOUNCE
335 unsigned int
get_ifan_ifindex(const void * buf)336 get_ifan_ifindex(const void *buf)
337 {
338 const struct if_announcemsghdr *ifan = buf;
339
340 return ifan->ifan_index;
341 }
342
343 int
get_ifan_what(const void * buf)344 get_ifan_what(const void *buf)
345 {
346 const struct if_announcemsghdr *ifan = buf;
347
348 return (int)ifan->ifan_what;
349 }
350 #endif
351
352 int
get_prefixlen(const void * buf)353 get_prefixlen(const void *buf)
354 {
355 const struct rt_msghdr *rtm = buf;
356 const struct sockaddr *sa, *rti_info[RTAX_MAX];
357 const unsigned char *p, *lim;
358
359 sa = (const struct sockaddr *)(rtm + 1);
360 get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
361 sa = rti_info[RTAX_NETMASK];
362
363 p = (const unsigned char *)(&SIN6(sa)->sin6_addr);
364 lim = (const unsigned char *)sa + sa->sa_len;
365 return prefixlen(p, lim);
366 }
367
368 int
prefixlen(const unsigned char * p,const unsigned char * lim)369 prefixlen(const unsigned char *p, const unsigned char *lim)
370 {
371 int masklen;
372
373 for (masklen = 0; p < lim; p++) {
374 switch (*p) {
375 case 0xff:
376 masklen += 8;
377 break;
378 case 0xfe:
379 masklen += 7;
380 break;
381 case 0xfc:
382 masklen += 6;
383 break;
384 case 0xf8:
385 masklen += 5;
386 break;
387 case 0xf0:
388 masklen += 4;
389 break;
390 case 0xe0:
391 masklen += 3;
392 break;
393 case 0xc0:
394 masklen += 2;
395 break;
396 case 0x80:
397 masklen += 1;
398 break;
399 case 0x00:
400 break;
401 default:
402 return -1;
403 }
404 }
405
406 return masklen;
407 }
408
409 int
rtmsg_type(const void * buf)410 rtmsg_type(const void *buf)
411 {
412 const struct rt_msghdr *rtm = buf;
413
414 return rtm->rtm_type;
415 }
416
417 const char *
rtmsg_typestr(const void * buf)418 rtmsg_typestr(const void *buf)
419 {
420 const struct rt_msghdr *rtm = buf;
421
422 return rtm->rtm_type < __arraycount(rtm_names)
423 ? rtm_names[rtm->rtm_type] : "*unknown*";
424 }
425
426 int
rtmsg_len(const void * buf)427 rtmsg_len(const void *buf)
428 {
429 const struct rt_msghdr *rtm = buf;
430
431 return rtm->rtm_msglen;
432 }
433