1 /* $NetBSD: in6_src.c,v 1.20.4.1 2007/12/02 22:43:43 bouyer 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/cdefs.h>
65 __KERNEL_RCSID(0, "$NetBSD: in6_src.c,v 1.20.4.1 2007/12/02 22:43:43 bouyer Exp $");
66
67 #include "opt_inet.h"
68
69 #include <sys/param.h>
70 #include <sys/systm.h>
71 #include <sys/malloc.h>
72 #include <sys/mbuf.h>
73 #include <sys/protosw.h>
74 #include <sys/socket.h>
75 #include <sys/socketvar.h>
76 #include <sys/ioctl.h>
77 #include <sys/errno.h>
78 #include <sys/time.h>
79 #include <sys/proc.h>
80
81 #include <net/if.h>
82 #include <net/route.h>
83
84 #include <netinet/in.h>
85 #include <netinet/in_var.h>
86 #include <netinet/in_systm.h>
87 #include <netinet/ip.h>
88 #include <netinet/in_pcb.h>
89 #include <netinet6/in6_var.h>
90 #include <netinet/ip6.h>
91 #include <netinet6/in6_pcb.h>
92 #include <netinet6/ip6_var.h>
93 #include <netinet6/nd6.h>
94 #ifdef ENABLE_DEFAULT_SCOPE
95 #include <netinet6/scope6_var.h>
96 #endif
97
98 #include <net/net_osdep.h>
99
100 /*
101 * Return an IPv6 address, which is the most appropriate for a given
102 * destination and user specified options.
103 * If necessary, this function lookups the routing table and returns
104 * an entry to the caller for later use.
105 */
106 struct in6_addr *
107 in6_selectsrc(dstsock, opts, mopts, ro, laddr, errorp)
108 struct sockaddr_in6 *dstsock;
109 struct ip6_pktopts *opts;
110 struct ip6_moptions *mopts;
111 struct route_in6 *ro;
112 struct in6_addr *laddr;
113 int *errorp;
114 {
115 struct in6_addr *dst;
116 struct in6_ifaddr *ia6 = 0;
117 struct in6_pktinfo *pi = NULL;
118
119 dst = &dstsock->sin6_addr;
120 *errorp = 0;
121
122 /*
123 * If the source address is explicitly specified by the caller,
124 * use it.
125 */
126 if (opts && (pi = opts->ip6po_pktinfo) &&
127 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr))
128 return (&pi->ipi6_addr);
129
130 /*
131 * If the source address is not specified but the socket(if any)
132 * is already bound, use the bound address.
133 */
134 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
135 return (laddr);
136
137 /*
138 * If the caller doesn't specify the source address but
139 * the outgoing interface, use an address associated with
140 * the interface.
141 */
142 if (pi && pi->ipi6_ifindex) {
143 /* XXX boundary check is assumed to be already done. */
144 ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex],
145 dst);
146 if (ia6 == 0) {
147 *errorp = EADDRNOTAVAIL;
148 return (0);
149 }
150 return (&satosin6(&ia6->ia_addr)->sin6_addr);
151 }
152
153 /*
154 * If the destination address is a link-local unicast address or
155 * a multicast address, and if the outgoing interface is specified
156 * by the sin6_scope_id filed, use an address associated with the
157 * interface.
158 * XXX: We're now trying to define more specific semantics of
159 * sin6_scope_id field, so this part will be rewritten in
160 * the near future.
161 */
162 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst)) &&
163 dstsock->sin6_scope_id) {
164 /*
165 * I'm not sure if boundary check for scope_id is done
166 * somewhere...
167 */
168 if (dstsock->sin6_scope_id < 0 ||
169 if_indexlim <= dstsock->sin6_scope_id ||
170 !ifindex2ifnet[dstsock->sin6_scope_id]) {
171 *errorp = ENXIO; /* XXX: better error? */
172 return (0);
173 }
174 ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id],
175 dst);
176 if (ia6 == 0) {
177 *errorp = EADDRNOTAVAIL;
178 return (0);
179 }
180 return (&satosin6(&ia6->ia_addr)->sin6_addr);
181 }
182
183 /*
184 * If the destination address is a multicast address and
185 * the outgoing interface for the address is specified
186 * by the caller, use an address associated with the interface.
187 * There is a sanity check here; if the destination has node-local
188 * scope, the outgoing interfacde should be a loopback address.
189 * Even if the outgoing interface is not specified, we also
190 * choose a loopback interface as the outgoing interface.
191 */
192 if (IN6_IS_ADDR_MULTICAST(dst)) {
193 struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
194
195 if (ifp == NULL && IN6_IS_ADDR_MC_NODELOCAL(dst))
196 ifp = lo0ifp;
197
198 if (ifp) {
199 ia6 = in6_ifawithscope(ifp, dst);
200 if (ia6 == 0) {
201 *errorp = EADDRNOTAVAIL;
202 return (0);
203 }
204 return (&satosin6(&ia6->ia_addr)->sin6_addr);
205 }
206 }
207
208 /*
209 * If the next hop address for the packet is specified
210 * by caller, use an address associated with the route
211 * to the next hop.
212 */
213 {
214 struct sockaddr_in6 *sin6_next;
215 struct rtentry *rt;
216
217 if (opts && opts->ip6po_nexthop) {
218 sin6_next = satosin6(opts->ip6po_nexthop);
219 rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL);
220 if (rt) {
221 ia6 = in6_ifawithscope(rt->rt_ifp, dst);
222 if (ia6 == 0)
223 ia6 = ifatoia6(rt->rt_ifa);
224 }
225 if (ia6 == 0) {
226 *errorp = EADDRNOTAVAIL;
227 return (0);
228 }
229 return (&satosin6(&ia6->ia_addr)->sin6_addr);
230 }
231 }
232
233 /*
234 * If route is known or can be allocated now,
235 * our src addr is taken from the i/f, else punt.
236 * Note that we should check the address family of the
237 * cached destination, in case of sharing the cache with IPv4.
238 */
239 if (ro) {
240 if (ro->ro_rt &&
241 (ro->ro_dst.sin6_family != AF_INET6 ||
242 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, dst))) {
243 RTFREE(ro->ro_rt);
244 ro->ro_rt = (struct rtentry *)0;
245 }
246 if (ro->ro_rt == (struct rtentry *)0 ||
247 ro->ro_rt->rt_ifp == (struct ifnet *)0) {
248 struct sockaddr_in6 *sa6;
249
250 /* No route yet, so try to acquire one */
251 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
252 sa6 = (struct sockaddr_in6 *)&ro->ro_dst;
253 sa6->sin6_family = AF_INET6;
254 sa6->sin6_len = sizeof(struct sockaddr_in6);
255 sa6->sin6_addr = *dst;
256 sa6->sin6_scope_id = dstsock->sin6_scope_id;
257 if (IN6_IS_ADDR_MULTICAST(dst)) {
258 ro->ro_rt = rtalloc1(&((struct route *)ro)
259 ->ro_dst, 0);
260 } else {
261 rtalloc((struct route *)ro);
262 }
263 }
264
265 /*
266 * in_pcbconnect() checks out IFF_LOOPBACK to skip using
267 * the address. But we don't know why it does so.
268 * It is necessary to ensure the scope even for lo0
269 * so doesn't check out IFF_LOOPBACK.
270 */
271
272 if (ro->ro_rt) {
273 ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst);
274 if (ia6 == 0) /* xxx scope error ?*/
275 ia6 = ifatoia6(ro->ro_rt->rt_ifa);
276 }
277 #if 0
278 /*
279 * xxx The followings are necessary? (kazu)
280 * I don't think so.
281 * It's for SO_DONTROUTE option in IPv4.(jinmei)
282 */
283 if (ia6 == 0) {
284 struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0};
285
286 sin6->sin6_addr = *dst;
287
288 ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6)));
289 if (ia6 == 0)
290 ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6)));
291 if (ia6 == 0)
292 return (0);
293 return (&satosin6(&ia6->ia_addr)->sin6_addr);
294 }
295 #endif /* 0 */
296 if (ia6 == 0) {
297 *errorp = EHOSTUNREACH; /* no route */
298 return (0);
299 }
300 return (&satosin6(&ia6->ia_addr)->sin6_addr);
301 }
302
303 *errorp = EADDRNOTAVAIL;
304 return (0);
305 }
306
307 /*
308 * Default hop limit selection. The precedence is as follows:
309 * 1. Hoplimit value specified via ioctl.
310 * 2. (If the outgoing interface is detected) the current
311 * hop limit of the interface specified by router advertisement.
312 * 3. The system default hoplimit.
313 */
314 int
315 in6_selecthlim(in6p, ifp)
316 struct in6pcb *in6p;
317 struct ifnet *ifp;
318 {
319 if (in6p && in6p->in6p_af != AF_INET6)
320 return (-1);
321
322 if (in6p && in6p->in6p_hops >= 0)
323 return (in6p->in6p_hops);
324 else if (ifp)
325 return (ND_IFINFO(ifp)->chlim);
326 else
327 return (ip6_defhlim);
328 }
329
330 /*
331 * Find an empty port and set it to the specified PCB.
332 */
333 int
334 in6_pcbsetport(laddr, in6p, p)
335 struct in6_addr *laddr;
336 struct in6pcb *in6p;
337 struct proc *p;
338 {
339 struct socket *so = in6p->in6p_socket;
340 struct inpcbtable *table = in6p->in6p_table;
341 int cnt;
342 u_int16_t min, max;
343 u_int16_t lport, *lastport;
344 int wild = 0;
345 void *t;
346
347 if (in6p->in6p_af != AF_INET6)
348 return (EINVAL);
349
350 /* XXX: this is redundant when called from in6_pcbbind */
351 if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0 &&
352 ((so->so_proto->pr_flags & PR_CONNREQUIRED) == 0 ||
353 (so->so_options & SO_ACCEPTCONN) == 0))
354 wild = 1;
355
356 if (in6p->in6p_flags & IN6P_LOWPORT) {
357 #ifndef IPNOPRIVPORTS
358 if (p == 0 || (suser(p->p_ucred, &p->p_acflag) != 0))
359 return (EACCES);
360 #endif
361 min = ip6_lowportmin;
362 max = ip6_lowportmax;
363 lastport = &table->inpt_lastlow;
364 } else {
365 min = ip6_anonportmin;
366 max = ip6_anonportmax;
367 lastport = &table->inpt_lastport;
368 }
369 if (min > max) { /* sanity check */
370 u_int16_t swp;
371
372 swp = min;
373 min = max;
374 max = swp;
375 }
376
377 lport = *lastport - 1;
378 for (cnt = max - min + 1; cnt; cnt--, lport--) {
379 if (lport < min || lport > max)
380 lport = max;
381 #ifdef INET
382 if (IN6_IS_ADDR_V4MAPPED(laddr)) {
383 t = in_pcblookup_port(table,
384 *(struct in_addr *)&in6p->in6p_laddr.s6_addr32[3],
385 htons(lport), wild);
386 } else
387 #endif
388 {
389 t = in6_pcblookup_port(table, laddr, htons(lport),
390 wild);
391 }
392 if (t == 0)
393 goto found;
394 }
395
396 return (EAGAIN);
397
398 found:
399 in6p->in6p_flags |= IN6P_ANONPORT;
400 *lastport = lport;
401 in6p->in6p_lport = htons(lport);
402 in6_pcbstate(in6p, IN6P_BOUND);
403 return (0); /* success */
404 }
405
406 /*
407 * generate kernel-internal form (scopeid embedded into s6_addr16[1]).
408 * If the address scope of is link-local, embed the interface index in the
409 * address. The routine determines our precedence
410 * between advanced API scope/interface specification and basic API
411 * specification.
412 *
413 * this function should be nuked in the future, when we get rid of
414 * embedded scopeid thing.
415 *
416 * XXX actually, it is over-specification to return ifp against sin6_scope_id.
417 * there can be multiple interfaces that belong to a particular scope zone
418 * (in specification, we have 1:N mapping between a scope zone and interfaces).
419 * we may want to change the function to return something other than ifp.
420 */
421 int
422 in6_embedscope(in6, sin6, in6p, ifpp)
423 struct in6_addr *in6;
424 const struct sockaddr_in6 *sin6;
425 struct in6pcb *in6p;
426 struct ifnet **ifpp;
427 {
428 struct ifnet *ifp = NULL;
429 u_int32_t scopeid;
430
431 *in6 = sin6->sin6_addr;
432 scopeid = sin6->sin6_scope_id;
433 if (ifpp)
434 *ifpp = NULL;
435
436 /*
437 * don't try to read sin6->sin6_addr beyond here, since the caller may
438 * ask us to overwrite existing sockaddr_in6
439 */
440
441 #ifdef ENABLE_DEFAULT_SCOPE
442 if (scopeid == 0)
443 scopeid = scope6_addr2default(in6);
444 #endif
445
446 if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
447 struct in6_pktinfo *pi;
448
449 /*
450 * KAME assumption: link id == interface id
451 */
452
453 if (in6p && in6p->in6p_outputopts &&
454 (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
455 pi->ipi6_ifindex) {
456 ifp = ifindex2ifnet[pi->ipi6_ifindex];
457 in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
458 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
459 in6p->in6p_moptions &&
460 in6p->in6p_moptions->im6o_multicast_ifp) {
461 ifp = in6p->in6p_moptions->im6o_multicast_ifp;
462 in6->s6_addr16[1] = htons(ifp->if_index);
463 } else if (scopeid) {
464 /* boundary check */
465 if (scopeid < 0 || if_indexlim <= scopeid ||
466 !ifindex2ifnet[scopeid])
467 return ENXIO; /* XXX EINVAL? */
468 ifp = ifindex2ifnet[scopeid];
469 /* XXX assignment to 16bit from 32bit variable */
470 in6->s6_addr16[1] = htons(scopeid & 0xffff);
471 }
472
473 if (ifpp)
474 *ifpp = ifp;
475 }
476
477 return 0;
478 }
479
480 /*
481 * generate standard sockaddr_in6 from embedded form.
482 * touches sin6_addr and sin6_scope_id only.
483 *
484 * this function should be nuked in the future, when we get rid of
485 * embedded scopeid thing.
486 */
487 int
488 in6_recoverscope(sin6, in6, ifp)
489 struct sockaddr_in6 *sin6;
490 const struct in6_addr *in6;
491 struct ifnet *ifp;
492 {
493 u_int32_t scopeid;
494
495 sin6->sin6_addr = *in6;
496
497 /*
498 * don't try to read *in6 beyond here, since the caller may
499 * ask us to overwrite existing sockaddr_in6
500 */
501
502 sin6->sin6_scope_id = 0;
503 if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
504 /*
505 * KAME assumption: link id == interface id
506 */
507 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
508 if (scopeid) {
509 /* sanity check */
510 if (scopeid < 0 || if_indexlim <= scopeid ||
511 !ifindex2ifnet[scopeid])
512 return ENXIO;
513 if (ifp && ifp->if_index != scopeid)
514 return ENXIO;
515 sin6->sin6_addr.s6_addr16[1] = 0;
516 sin6->sin6_scope_id = scopeid;
517 }
518 }
519
520 return 0;
521 }
522
523 /*
524 * just clear the embedded scope identifer.
525 */
526 void
527 in6_clearscope(addr)
528 struct in6_addr *addr;
529 {
530 if (IN6_IS_SCOPE_LINKLOCAL(addr))
531 addr->s6_addr16[1] = 0;
532 }
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