Line data Source code
1 : /* $OpenBSD: in6_src.c,v 1.81 2016/12/02 11:16:04 mpi 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/protosw.h>
68 : #include <sys/socket.h>
69 : #include <sys/socketvar.h>
70 : #include <sys/ioctl.h>
71 : #include <sys/errno.h>
72 : #include <sys/time.h>
73 :
74 : #include <net/if.h>
75 : #include <net/if_var.h>
76 : #include <net/route.h>
77 :
78 : #include <netinet/in.h>
79 : #include <netinet/ip.h>
80 : #include <netinet/in_pcb.h>
81 : #include <netinet6/in6_var.h>
82 : #include <netinet/ip6.h>
83 : #include <netinet6/ip6_var.h>
84 : #include <netinet6/nd6.h>
85 :
86 : int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *,
87 : struct ip6_moptions *, struct route_in6 *, struct ifnet **, u_int);
88 :
89 : /*
90 : * Return an IPv6 address, which is the most appropriate for a given
91 : * destination and pcb. We need the additional opt parameter because
92 : * the values set at pcb level can be overriden via cmsg.
93 : */
94 : int
95 0 : in6_pcbselsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock,
96 : struct inpcb *inp, struct ip6_pktopts *opts)
97 : {
98 0 : struct ip6_moptions *mopts = inp->inp_moptions6;
99 0 : struct route_in6 *ro = &inp->inp_route6;
100 0 : struct in6_addr *laddr = &inp->inp_laddr6;
101 0 : u_int rtableid = inp->inp_rtableid;
102 0 : struct ifnet *ifp = NULL;
103 : struct in6_addr *dst;
104 : struct in6_ifaddr *ia6 = NULL;
105 : struct in6_pktinfo *pi = NULL;
106 : int error;
107 :
108 0 : 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 0 : if (opts && (pi = opts->ip6po_pktinfo) &&
117 0 : !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
118 0 : struct sockaddr_in6 sa6;
119 :
120 : /* get the outgoing interface */
121 0 : error = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid);
122 0 : if (error)
123 0 : return (error);
124 :
125 0 : bzero(&sa6, sizeof(sa6));
126 0 : sa6.sin6_family = AF_INET6;
127 0 : sa6.sin6_len = sizeof(sa6);
128 0 : sa6.sin6_addr = pi->ipi6_addr;
129 :
130 0 : if (ifp && IN6_IS_SCOPE_EMBED(&sa6.sin6_addr))
131 0 : sa6.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
132 0 : if_put(ifp); /* put reference from in6_selectif */
133 :
134 0 : ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid));
135 0 : if (ia6 == NULL || (ia6->ia6_flags &
136 : (IN6_IFF_ANYCAST|IN6_IFF_TENTATIVE|IN6_IFF_DUPLICATED)))
137 0 : return (EADDRNOTAVAIL);
138 :
139 0 : pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */
140 :
141 0 : *in6src = &pi->ipi6_addr;
142 0 : return (0);
143 0 : }
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 0 : if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) {
150 0 : *in6src = laddr;
151 0 : 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 0 : if (pi && pi->ipi6_ifindex) {
160 0 : ifp = if_get(pi->ipi6_ifindex);
161 0 : if (ifp == NULL)
162 0 : return (ENXIO); /* XXX: better error? */
163 :
164 0 : ia6 = in6_ifawithscope(ifp, dst, rtableid);
165 0 : if_put(ifp);
166 :
167 0 : if (ia6 == NULL)
168 0 : return (EADDRNOTAVAIL);
169 :
170 0 : *in6src = &ia6->ia_addr.sin6_addr;
171 0 : return (0);
172 : }
173 :
174 0 : error = in6_selectsrc(in6src, dstsock, mopts, rtableid);
175 0 : if (error != EADDRNOTAVAIL)
176 0 : 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 0 : if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) ||
183 0 : !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) {
184 0 : rtfree(ro->ro_rt);
185 0 : ro->ro_rt = NULL;
186 0 : }
187 0 : if (ro->ro_rt == NULL) {
188 : struct sockaddr_in6 *sa6;
189 :
190 : /* No route yet, so try to acquire one */
191 0 : bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
192 0 : ro->ro_tableid = rtableid;
193 : sa6 = &ro->ro_dst;
194 0 : sa6->sin6_family = AF_INET6;
195 0 : sa6->sin6_len = sizeof(struct sockaddr_in6);
196 0 : sa6->sin6_addr = *dst;
197 0 : sa6->sin6_scope_id = dstsock->sin6_scope_id;
198 0 : ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst),
199 0 : RT_RESOLVE, ro->ro_tableid);
200 0 : }
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 0 : if (ro->ro_rt) {
210 0 : ifp = if_get(ro->ro_rt->rt_ifidx);
211 0 : if (ifp != NULL) {
212 0 : ia6 = in6_ifawithscope(ifp, dst, rtableid);
213 0 : if_put(ifp);
214 0 : }
215 0 : if (ia6 == NULL) /* xxx scope error ?*/
216 0 : ia6 = ifatoia6(ro->ro_rt->rt_ifa);
217 : }
218 0 : if (ia6 == NULL)
219 0 : return (EHOSTUNREACH); /* no route */
220 :
221 0 : *in6src = &ia6->ia_addr.sin6_addr;
222 0 : return (0);
223 0 : }
224 :
225 : /*
226 : * Return an IPv6 address, which is the most appropriate for a given
227 : * destination and multicast options.
228 : * If necessary, this function lookups the routing table and returns
229 : * an entry to the caller for later use.
230 : */
231 : int
232 0 : in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock,
233 : struct ip6_moptions *mopts, unsigned int rtableid)
234 : {
235 : struct ifnet *ifp = NULL;
236 : struct in6_addr *dst;
237 : struct in6_ifaddr *ia6 = NULL;
238 :
239 0 : dst = &dstsock->sin6_addr;
240 :
241 : /*
242 : * If the destination address is a link-local unicast address or
243 : * a link/interface-local multicast address, and if the outgoing
244 : * interface is specified by the sin6_scope_id filed, use an address
245 : * associated with the interface.
246 : * XXX: We're now trying to define more specific semantics of
247 : * sin6_scope_id field, so this part will be rewritten in
248 : * the near future.
249 : */
250 0 : if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) ||
251 0 : IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) {
252 0 : ifp = if_get(dstsock->sin6_scope_id);
253 0 : if (ifp == NULL)
254 0 : return (ENXIO); /* XXX: better error? */
255 :
256 0 : ia6 = in6_ifawithscope(ifp, dst, rtableid);
257 0 : if_put(ifp);
258 :
259 0 : if (ia6 == NULL)
260 0 : return (EADDRNOTAVAIL);
261 :
262 0 : *in6src = &ia6->ia_addr.sin6_addr;
263 0 : return (0);
264 : }
265 :
266 : /*
267 : * If the destination address is a multicast address and
268 : * the outgoing interface for the address is specified
269 : * by the caller, use an address associated with the interface.
270 : * Even if the outgoing interface is not specified, we also
271 : * choose a loopback interface as the outgoing interface.
272 : */
273 0 : if (IN6_IS_ADDR_MULTICAST(dst)) {
274 0 : ifp = mopts ? if_get(mopts->im6o_ifidx) : NULL;
275 :
276 0 : if (!ifp && dstsock->sin6_scope_id)
277 0 : ifp = if_get(htons(dstsock->sin6_scope_id));
278 :
279 0 : if (ifp) {
280 0 : ia6 = in6_ifawithscope(ifp, dst, rtableid);
281 0 : if_put(ifp);
282 :
283 0 : if (ia6 == NULL)
284 0 : return (EADDRNOTAVAIL);
285 :
286 0 : *in6src = &ia6->ia_addr.sin6_addr;
287 0 : return (0);
288 : }
289 : }
290 :
291 0 : return (EADDRNOTAVAIL);
292 0 : }
293 :
294 : struct rtentry *
295 0 : in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
296 : struct route_in6 *ro, unsigned int rtableid)
297 : {
298 : struct in6_addr *dst;
299 :
300 0 : dst = &dstsock->sin6_addr;
301 :
302 : /*
303 : * Use a cached route if it exists and is valid, else try to allocate
304 : * a new one.
305 : */
306 0 : if (ro) {
307 0 : if (rtisvalid(ro->ro_rt))
308 0 : KASSERT(sin6tosa(&ro->ro_dst)->sa_family == AF_INET6);
309 0 : if (!rtisvalid(ro->ro_rt) ||
310 0 : !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) {
311 0 : rtfree(ro->ro_rt);
312 0 : ro->ro_rt = NULL;
313 0 : }
314 0 : if (ro->ro_rt == NULL) {
315 : struct sockaddr_in6 *sa6;
316 :
317 : /* No route yet, so try to acquire one */
318 0 : bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
319 0 : ro->ro_tableid = rtableid;
320 : sa6 = &ro->ro_dst;
321 0 : *sa6 = *dstsock;
322 0 : sa6->sin6_scope_id = 0;
323 0 : ro->ro_tableid = rtableid;
324 0 : ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst),
325 0 : NULL, ro->ro_tableid);
326 0 : }
327 :
328 : /*
329 : * Check if the outgoing interface conflicts with
330 : * the interface specified by ipi6_ifindex (if specified).
331 : * Note that loopback interface is always okay.
332 : * (this may happen when we are sending a packet to one of
333 : * our own addresses.)
334 : */
335 0 : if (opts && opts->ip6po_pktinfo &&
336 0 : opts->ip6po_pktinfo->ipi6_ifindex) {
337 0 : if (ro->ro_rt != NULL &&
338 0 : !ISSET(ro->ro_rt->rt_flags, RTF_LOCAL) &&
339 0 : ro->ro_rt->rt_ifidx !=
340 : opts->ip6po_pktinfo->ipi6_ifindex) {
341 0 : return (NULL);
342 : }
343 : }
344 :
345 0 : return (ro->ro_rt);
346 : }
347 :
348 0 : return (NULL);
349 0 : }
350 :
351 : int
352 0 : in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
353 : struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp,
354 : u_int rtableid)
355 : {
356 : struct rtentry *rt = NULL;
357 : struct in6_pktinfo *pi = NULL;
358 :
359 : /* If the caller specify the outgoing interface explicitly, use it. */
360 0 : if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
361 0 : *retifp = if_get(pi->ipi6_ifindex);
362 0 : if (*retifp != NULL)
363 0 : return (0);
364 : }
365 :
366 : /*
367 : * If the destination address is a multicast address and the outgoing
368 : * interface for the address is specified by the caller, use it.
369 : */
370 0 : if (IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) &&
371 0 : mopts != NULL && (*retifp = if_get(mopts->im6o_ifidx)) != NULL)
372 0 : return (0);
373 :
374 0 : rt = in6_selectroute(dstsock, opts, ro, rtableid);
375 0 : if (rt == NULL)
376 0 : return (EHOSTUNREACH);
377 :
378 : /*
379 : * do not use a rejected or black hole route.
380 : * XXX: this check should be done in the L2 output routine.
381 : * However, if we skipped this check here, we'd see the following
382 : * scenario:
383 : * - install a rejected route for a scoped address prefix
384 : * (like fe80::/10)
385 : * - send a packet to a destination that matches the scoped prefix,
386 : * with ambiguity about the scope zone.
387 : * - pick the outgoing interface from the route, and disambiguate the
388 : * scope zone with the interface.
389 : * - ip6_output() would try to get another route with the "new"
390 : * destination, which may be valid.
391 : * - we'd see no error on output.
392 : * Although this may not be very harmful, it should still be confusing.
393 : * We thus reject the case here.
394 : */
395 0 : if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE)))
396 0 : return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
397 :
398 0 : if (rt != NULL)
399 0 : *retifp = if_get(rt->rt_ifidx);
400 :
401 0 : return (0);
402 0 : }
403 :
404 : int
405 0 : in6_selecthlim(struct inpcb *in6p)
406 : {
407 0 : if (in6p && in6p->inp_hops >= 0)
408 0 : return (in6p->inp_hops);
409 :
410 0 : return (ip6_defhlim);
411 0 : }
412 :
413 : /*
414 : * generate kernel-internal form (scopeid embedded into s6_addr16[1]).
415 : * If the address scope of is link-local, embed the interface index in the
416 : * address. The routine determines our precedence
417 : * between advanced API scope/interface specification and basic API
418 : * specification.
419 : *
420 : * this function should be nuked in the future, when we get rid of
421 : * embedded scopeid thing.
422 : *
423 : * XXX actually, it is over-specification to return ifp against sin6_scope_id.
424 : * there can be multiple interfaces that belong to a particular scope zone
425 : * (in specification, we have 1:N mapping between a scope zone and interfaces).
426 : * we may want to change the function to return something other than ifp.
427 : */
428 : int
429 0 : in6_embedscope(struct in6_addr *in6, const struct sockaddr_in6 *sin6,
430 : struct inpcb *in6p)
431 : {
432 : struct ifnet *ifp = NULL;
433 : u_int32_t scopeid;
434 :
435 0 : *in6 = sin6->sin6_addr;
436 0 : scopeid = sin6->sin6_scope_id;
437 :
438 : /*
439 : * don't try to read sin6->sin6_addr beyond here, since the caller may
440 : * ask us to overwrite existing sockaddr_in6
441 : */
442 :
443 0 : if (IN6_IS_SCOPE_EMBED(in6)) {
444 : struct in6_pktinfo *pi;
445 :
446 : /*
447 : * KAME assumption: link id == interface id
448 : */
449 :
450 0 : if (in6p && in6p->inp_outputopts6 &&
451 0 : (pi = in6p->inp_outputopts6->ip6po_pktinfo) &&
452 0 : pi->ipi6_ifindex) {
453 0 : ifp = if_get(pi->ipi6_ifindex);
454 0 : if (ifp == NULL)
455 0 : return ENXIO; /* XXX EINVAL? */
456 0 : in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
457 0 : } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
458 0 : in6p->inp_moptions6 &&
459 0 : (ifp = if_get(in6p->inp_moptions6->im6o_ifidx))) {
460 0 : in6->s6_addr16[1] = htons(ifp->if_index);
461 0 : } else if (scopeid) {
462 0 : ifp = if_get(scopeid);
463 0 : if (ifp == NULL)
464 0 : return ENXIO; /* XXX EINVAL? */
465 : /*XXX assignment to 16bit from 32bit variable */
466 0 : in6->s6_addr16[1] = htons(scopeid & 0xffff);
467 0 : }
468 0 : if_put(ifp);
469 0 : }
470 :
471 0 : return 0;
472 0 : }
473 :
474 : /*
475 : * generate standard sockaddr_in6 from embedded form.
476 : * touches sin6_addr and sin6_scope_id only.
477 : *
478 : * this function should be nuked in the future, when we get rid of
479 : * embedded scopeid thing.
480 : */
481 : void
482 0 : in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6)
483 : {
484 : u_int32_t scopeid;
485 :
486 0 : sin6->sin6_addr = *in6;
487 :
488 : /*
489 : * don't try to read *in6 beyond here, since the caller may
490 : * ask us to overwrite existing sockaddr_in6
491 : */
492 :
493 0 : sin6->sin6_scope_id = 0;
494 0 : if (IN6_IS_SCOPE_EMBED(in6)) {
495 : /*
496 : * KAME assumption: link id == interface id
497 : */
498 0 : scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
499 0 : if (scopeid) {
500 0 : sin6->sin6_addr.s6_addr16[1] = 0;
501 0 : sin6->sin6_scope_id = scopeid;
502 0 : }
503 : }
504 0 : }
505 :
506 : /*
507 : * just clear the embedded scope identifer.
508 : */
509 : void
510 0 : in6_clearscope(struct in6_addr *addr)
511 : {
512 0 : if (IN6_IS_SCOPE_EMBED(addr))
513 0 : addr->s6_addr16[1] = 0;
514 0 : }
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