1 /* $OpenBSD: in6_src.c,v 1.86 2022/02/22 01:15:02 guenther Exp $ */
2 /* $KAME: in6_src.c,v 1.36 2001/02/06 04:08:17 itojun 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 /*
34 * Copyright (c) 1982, 1986, 1991, 1993
35 * The Regents of the University of California. All rights reserved.
36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 * notice, this list of conditions and the following disclaimer.
42 * 2. Redistributions in binary form must reproduce the above copyright
43 * notice, this list of conditions and the following disclaimer in the
44 * documentation and/or other materials provided with the distribution.
45 * 3. Neither the name of the University nor the names of its contributors
46 * may be used to endorse or promote products derived from this software
47 * without specific prior written permission.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 *
61 * @(#)in_pcb.c 8.2 (Berkeley) 1/4/94
62 */
63
64 #include <sys/param.h>
65 #include <sys/systm.h>
66 #include <sys/mbuf.h>
67 #include <sys/socket.h>
68 #include <sys/socketvar.h>
69 #include <sys/ioctl.h>
70 #include <sys/errno.h>
71 #include <sys/time.h>
72
73 #include <net/if.h>
74 #include <net/if_var.h>
75 #include <net/route.h>
76
77 #include <netinet/in.h>
78 #include <netinet/ip.h>
79 #include <netinet/in_pcb.h>
80 #include <netinet6/in6_var.h>
81 #include <netinet/ip6.h>
82 #include <netinet6/ip6_var.h>
83 #include <netinet6/nd6.h>
84
85 int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *,
86 struct ip6_moptions *, struct route_in6 *, struct ifnet **, u_int);
87
88 /*
89 * Return an IPv6 address, which is the most appropriate for a given
90 * destination and pcb. We need the additional opt parameter because
91 * the values set at pcb level can be overridden via cmsg.
92 */
93 int
94 in6_pcbselsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock,
95 struct inpcb *inp, struct ip6_pktopts *opts)
96 {
97 struct ip6_moptions *mopts = inp->inp_moptions6;
98 struct route_in6 *ro = &inp->inp_route6;
99 struct in6_addr *laddr = &inp->inp_laddr6;
100 u_int rtableid = inp->inp_rtableid;
101 struct ifnet *ifp = NULL;
102 struct sockaddr *ip6_source = NULL;
103 struct in6_addr *dst;
104 struct in6_ifaddr *ia6 = NULL;
105 struct in6_pktinfo *pi = NULL;
106 int error;
107
108 dst = &dstsock->sin6_addr;
109
110 /*
111 * If the source address is explicitly specified by the caller,
112 * check if the requested source address is indeed a unicast address
113 * assigned to the node, and can be used as the packet's source
114 * address. If everything is okay, use the address as source.
115 */
116 if (opts && (pi = opts->ip6po_pktinfo) &&
117 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
118 struct sockaddr_in6 sa6;
119
120 /* get the outgoing interface */
121 error = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid);
122 if (error)
123 return (error);
124
125 bzero(&sa6, sizeof(sa6));
126 sa6.sin6_family = AF_INET6;
127 sa6.sin6_len = sizeof(sa6);
128 sa6.sin6_addr = pi->ipi6_addr;
129
130 if (ifp && IN6_IS_SCOPE_EMBED(&sa6.sin6_addr))
131 sa6.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
132 if_put(ifp); /* put reference from in6_selectif */
133
134 ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid));
135 if (ia6 == NULL || (ia6->ia6_flags &
136 (IN6_IFF_ANYCAST|IN6_IFF_TENTATIVE|IN6_IFF_DUPLICATED)))
137 return (EADDRNOTAVAIL);
138
139 pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */
140
141 *in6src = &pi->ipi6_addr;
142 return (0);
143 }
144
145 /*
146 * If the source address is not specified but the socket(if any)
147 * is already bound, use the bound address.
148 */
149 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) {
150 *in6src = laddr;
151 return (0);
152 }
153
154 /*
155 * If the caller doesn't specify the source address but
156 * the outgoing interface, use an address associated with
157 * the interface.
158 */
159 if (pi && pi->ipi6_ifindex) {
160 ifp = if_get(pi->ipi6_ifindex);
161 if (ifp == NULL)
162 return (ENXIO); /* XXX: better error? */
163
164 ia6 = in6_ifawithscope(ifp, dst, rtableid);
165 if_put(ifp);
166
167 if (ia6 == NULL)
168 return (EADDRNOTAVAIL);
169
170 *in6src = &ia6->ia_addr.sin6_addr;
171 return (0);
172 }
173
174 error = in6_selectsrc(in6src, dstsock, mopts, rtableid);
175 if (error != EADDRNOTAVAIL)
176 return (error);
177
178 /*
179 * If route is known or can be allocated now,
180 * our src addr is taken from the i/f, else punt.
181 */
182 if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) ||
183 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) {
184 rtfree(ro->ro_rt);
185 ro->ro_rt = NULL;
186 }
187 if (ro->ro_rt == NULL) {
188 struct sockaddr_in6 *sa6;
189
190 /* No route yet, so try to acquire one */
191 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
192 ro->ro_tableid = rtableid;
193 sa6 = &ro->ro_dst;
194 sa6->sin6_family = AF_INET6;
195 sa6->sin6_len = sizeof(struct sockaddr_in6);
196 sa6->sin6_addr = *dst;
197 sa6->sin6_scope_id = dstsock->sin6_scope_id;
198 ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst),
199 RT_RESOLVE, ro->ro_tableid);
200 }
201
202 /*
203 * in_pcbconnect() checks out IFF_LOOPBACK to skip using
204 * the address. But we don't know why it does so.
205 * It is necessary to ensure the scope even for lo0
206 * so doesn't check out IFF_LOOPBACK.
207 */
208
209 if (ro->ro_rt) {
210 ifp = if_get(ro->ro_rt->rt_ifidx);
211 if (ifp != NULL) {
212 ia6 = in6_ifawithscope(ifp, dst, rtableid);
213 if_put(ifp);
214 }
215 if (ia6 == NULL) /* xxx scope error ?*/
216 ia6 = ifatoia6(ro->ro_rt->rt_ifa);
217 }
218
219 /*
220 * Use preferred source address if :
221 * - destination is not onlink
222 * - preferred source address is set
223 * - output interface is UP
224 */
225 if (ro->ro_rt && !(ro->ro_rt->rt_flags & RTF_LLINFO) &&
226 !(ro->ro_rt->rt_flags & RTF_HOST)) {
227 ip6_source = rtable_getsource(rtableid, AF_INET6);
228 if (ip6_source != NULL) {
229 struct ifaddr *ifa;
230 if ((ifa = ifa_ifwithaddr(ip6_source, rtableid)) !=
231 NULL && ISSET(ifa->ifa_ifp->if_flags, IFF_UP)) {
232 *in6src = &satosin6(ip6_source)->sin6_addr;
233 return (0);
234 }
235 }
236 }
237
238 if (ia6 == NULL)
239 return (EHOSTUNREACH); /* no route */
240
241 *in6src = &ia6->ia_addr.sin6_addr;
242 return (0);
243 }
244
245 /*
246 * Return an IPv6 address, which is the most appropriate for a given
247 * destination and multicast options.
248 * If necessary, this function lookups the routing table and returns
249 * an entry to the caller for later use.
250 */
251 int
252 in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock,
253 struct ip6_moptions *mopts, unsigned int rtableid)
254 {
255 struct ifnet *ifp = NULL;
256 struct in6_addr *dst;
257 struct in6_ifaddr *ia6 = NULL;
258
259 dst = &dstsock->sin6_addr;
260
261 /*
262 * If the destination address is a link-local unicast address or
263 * a link/interface-local multicast address, and if the outgoing
264 * interface is specified by the sin6_scope_id filed, use an address
265 * associated with the interface.
266 * XXX: We're now trying to define more specific semantics of
267 * sin6_scope_id field, so this part will be rewritten in
268 * the near future.
269 */
270 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) ||
271 IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) {
272 ifp = if_get(dstsock->sin6_scope_id);
273 if (ifp == NULL)
274 return (ENXIO); /* XXX: better error? */
275
276 ia6 = in6_ifawithscope(ifp, dst, rtableid);
277 if_put(ifp);
278
279 if (ia6 == NULL)
280 return (EADDRNOTAVAIL);
281
282 *in6src = &ia6->ia_addr.sin6_addr;
283 return (0);
284 }
285
286 /*
287 * If the destination address is a multicast address and
288 * the outgoing interface for the address is specified
289 * by the caller, use an address associated with the interface.
290 * Even if the outgoing interface is not specified, we also
291 * choose a loopback interface as the outgoing interface.
292 */
293 if (IN6_IS_ADDR_MULTICAST(dst)) {
294 ifp = mopts ? if_get(mopts->im6o_ifidx) : NULL;
295
296 if (!ifp && dstsock->sin6_scope_id)
297 ifp = if_get(htons(dstsock->sin6_scope_id));
298
299 if (ifp) {
300 ia6 = in6_ifawithscope(ifp, dst, rtableid);
301 if_put(ifp);
302
303 if (ia6 == NULL)
304 return (EADDRNOTAVAIL);
305
306 *in6src = &ia6->ia_addr.sin6_addr;
307 return (0);
308 }
309 }
310
311 return (EADDRNOTAVAIL);
312 }
313
314 struct rtentry *
315 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
316 struct route_in6 *ro, unsigned int rtableid)
317 {
318 struct in6_addr *dst;
319
320 dst = &dstsock->sin6_addr;
321
322 /*
323 * Use a cached route if it exists and is valid, else try to allocate
324 * a new one.
325 */
326 if (ro) {
327 if (rtisvalid(ro->ro_rt))
328 KASSERT(sin6tosa(&ro->ro_dst)->sa_family == AF_INET6);
329 if (!rtisvalid(ro->ro_rt) ||
330 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) {
331 rtfree(ro->ro_rt);
332 ro->ro_rt = NULL;
333 }
334 if (ro->ro_rt == NULL) {
335 struct sockaddr_in6 *sa6;
336
337 /* No route yet, so try to acquire one */
338 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
339 ro->ro_tableid = rtableid;
340 sa6 = &ro->ro_dst;
341 *sa6 = *dstsock;
342 sa6->sin6_scope_id = 0;
343 ro->ro_tableid = rtableid;
344 ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst),
345 NULL, ro->ro_tableid);
346 }
347
348 /*
349 * Check if the outgoing interface conflicts with
350 * the interface specified by ipi6_ifindex (if specified).
351 * Note that loopback interface is always okay.
352 * (this may happen when we are sending a packet to one of
353 * our own addresses.)
354 */
355 if (opts && opts->ip6po_pktinfo &&
356 opts->ip6po_pktinfo->ipi6_ifindex) {
357 if (ro->ro_rt != NULL &&
358 !ISSET(ro->ro_rt->rt_flags, RTF_LOCAL) &&
359 ro->ro_rt->rt_ifidx !=
360 opts->ip6po_pktinfo->ipi6_ifindex) {
361 return (NULL);
362 }
363 }
364
365 return (ro->ro_rt);
366 }
367
368 return (NULL);
369 }
370
371 int
372 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
373 struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp,
374 u_int rtableid)
375 {
376 struct rtentry *rt = NULL;
377 struct in6_pktinfo *pi = NULL;
378
379 /* If the caller specify the outgoing interface explicitly, use it. */
380 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
381 *retifp = if_get(pi->ipi6_ifindex);
382 if (*retifp != NULL)
383 return (0);
384 }
385
386 /*
387 * If the destination address is a multicast address and the outgoing
388 * interface for the address is specified by the caller, use it.
389 */
390 if (IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) &&
391 mopts != NULL && (*retifp = if_get(mopts->im6o_ifidx)) != NULL)
392 return (0);
393
394 rt = in6_selectroute(dstsock, opts, ro, rtableid);
395 if (rt == NULL)
396 return (EHOSTUNREACH);
397
398 /*
399 * do not use a rejected or black hole route.
400 * XXX: this check should be done in the L2 output routine.
401 * However, if we skipped this check here, we'd see the following
402 * scenario:
403 * - install a rejected route for a scoped address prefix
404 * (like fe80::/10)
405 * - send a packet to a destination that matches the scoped prefix,
406 * with ambiguity about the scope zone.
407 * - pick the outgoing interface from the route, and disambiguate the
408 * scope zone with the interface.
409 * - ip6_output() would try to get another route with the "new"
410 * destination, which may be valid.
411 * - we'd see no error on output.
412 * Although this may not be very harmful, it should still be confusing.
413 * We thus reject the case here.
414 */
415 if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE)))
416 return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
417
418 if (rt != NULL)
419 *retifp = if_get(rt->rt_ifidx);
420
421 return (0);
422 }
423
424 int
425 in6_selecthlim(struct inpcb *in6p)
426 {
427 if (in6p && in6p->inp_hops >= 0)
428 return (in6p->inp_hops);
429
430 return (ip6_defhlim);
431 }
432
433 /*
434 * generate kernel-internal form (scopeid embedded into s6_addr16[1]).
435 * If the address scope of is link-local, embed the interface index in the
436 * address. The routine determines our precedence
437 * between advanced API scope/interface specification and basic API
438 * specification.
439 *
440 * this function should be nuked in the future, when we get rid of
441 * embedded scopeid thing.
442 *
443 * XXX actually, it is over-specification to return ifp against sin6_scope_id.
444 * there can be multiple interfaces that belong to a particular scope zone
445 * (in specification, we have 1:N mapping between a scope zone and interfaces).
446 * we may want to change the function to return something other than ifp.
447 */
448 int
449 in6_embedscope(struct in6_addr *in6, const struct sockaddr_in6 *sin6,
450 struct inpcb *in6p)
451 {
452 struct ifnet *ifp = NULL;
453 u_int32_t scopeid;
454
455 *in6 = sin6->sin6_addr;
456 scopeid = sin6->sin6_scope_id;
457
458 /*
459 * don't try to read sin6->sin6_addr beyond here, since the caller may
460 * ask us to overwrite existing sockaddr_in6
461 */
462
463 if (IN6_IS_SCOPE_EMBED(in6)) {
464 struct in6_pktinfo *pi;
465
466 /*
467 * KAME assumption: link id == interface id
468 */
469
470 if (in6p && in6p->inp_outputopts6 &&
471 (pi = in6p->inp_outputopts6->ip6po_pktinfo) &&
472 pi->ipi6_ifindex) {
473 ifp = if_get(pi->ipi6_ifindex);
474 if (ifp == NULL)
475 return ENXIO; /* XXX EINVAL? */
476 in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
477 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
478 in6p->inp_moptions6 &&
479 (ifp = if_get(in6p->inp_moptions6->im6o_ifidx))) {
480 in6->s6_addr16[1] = htons(ifp->if_index);
481 } else if (scopeid) {
482 ifp = if_get(scopeid);
483 if (ifp == NULL)
484 return ENXIO; /* XXX EINVAL? */
485 /*XXX assignment to 16bit from 32bit variable */
486 in6->s6_addr16[1] = htons(scopeid & 0xffff);
487 }
488 if_put(ifp);
489 }
490
491 return 0;
492 }
493
494 /*
495 * generate standard sockaddr_in6 from embedded form.
496 * touches sin6_addr and sin6_scope_id only.
497 *
498 * this function should be nuked in the future, when we get rid of
499 * embedded scopeid thing.
500 */
501 void
502 in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6)
503 {
504 u_int32_t scopeid;
505
506 sin6->sin6_addr = *in6;
507
508 /*
509 * don't try to read *in6 beyond here, since the caller may
510 * ask us to overwrite existing sockaddr_in6
511 */
512
513 sin6->sin6_scope_id = 0;
514 if (IN6_IS_SCOPE_EMBED(in6)) {
515 /*
516 * KAME assumption: link id == interface id
517 */
518 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
519 if (scopeid) {
520 sin6->sin6_addr.s6_addr16[1] = 0;
521 sin6->sin6_scope_id = scopeid;
522 }
523 }
524 }
525
526 /*
527 * just clear the embedded scope identifier.
528 */
529 void
530 in6_clearscope(struct in6_addr *addr)
531 {
532 if (IN6_IS_SCOPE_EMBED(addr))
533 addr->s6_addr16[1] = 0;
534 }
Cache object: 6101863f627ea3f9f1da225d0cbac799
|