1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * 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 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * $KAME: in6_src.c,v 1.132 2003/08/26 04:42:27 keiichi Exp $
32 */
33
34 /*-
35 * Copyright (c) 1982, 1986, 1991, 1993
36 * The Regents of the University of California. All rights reserved.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. Neither the name of the University nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60 * SUCH DAMAGE.
61 *
62 * @(#)in_pcb.c 8.2 (Berkeley) 1/4/94
63 */
64
65 #include <sys/cdefs.h>
66 #include "opt_inet.h"
67 #include "opt_inet6.h"
68 #include <sys/param.h>
69 #include <sys/systm.h>
70 #include <sys/lock.h>
71 #include <sys/malloc.h>
72 #include <sys/mbuf.h>
73 #include <sys/priv.h>
74 #include <sys/protosw.h>
75 #include <sys/socket.h>
76 #include <sys/socketvar.h>
77 #include <sys/sockio.h>
78 #include <sys/sysctl.h>
79 #include <sys/errno.h>
80 #include <sys/time.h>
81 #include <sys/jail.h>
82 #include <sys/kernel.h>
83 #include <sys/rmlock.h>
84 #include <sys/sx.h>
85
86 #include <net/if.h>
87 #include <net/if_var.h>
88 #include <net/if_dl.h>
89 #include <net/if_private.h>
90 #include <net/route.h>
91 #include <net/route/nhop.h>
92 #include <net/if_llatbl.h>
93
94 #include <netinet/in.h>
95 #include <netinet/in_var.h>
96 #include <netinet/in_systm.h>
97 #include <netinet/ip.h>
98 #include <netinet/in_pcb.h>
99 #include <netinet/ip_var.h>
100 #include <netinet/udp.h>
101 #include <netinet/udp_var.h>
102
103 #include <netinet6/in6_var.h>
104 #include <netinet/ip6.h>
105 #include <netinet6/in6_fib.h>
106 #include <netinet6/in6_pcb.h>
107 #include <netinet6/ip6_var.h>
108 #include <netinet6/scope6_var.h>
109 #include <netinet6/nd6.h>
110
111 static struct mtx addrsel_lock;
112 #define ADDRSEL_LOCK_INIT() mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF)
113 #define ADDRSEL_LOCK() mtx_lock(&addrsel_lock)
114 #define ADDRSEL_UNLOCK() mtx_unlock(&addrsel_lock)
115 #define ADDRSEL_LOCK_ASSERT() mtx_assert(&addrsel_lock, MA_OWNED)
116
117 static struct sx addrsel_sxlock;
118 #define ADDRSEL_SXLOCK_INIT() sx_init(&addrsel_sxlock, "addrsel_sxlock")
119 #define ADDRSEL_SLOCK() sx_slock(&addrsel_sxlock)
120 #define ADDRSEL_SUNLOCK() sx_sunlock(&addrsel_sxlock)
121 #define ADDRSEL_XLOCK() sx_xlock(&addrsel_sxlock)
122 #define ADDRSEL_XUNLOCK() sx_xunlock(&addrsel_sxlock)
123
124 #define ADDR_LABEL_NOTAPP (-1)
125 VNET_DEFINE_STATIC(struct in6_addrpolicy, defaultaddrpolicy);
126 #define V_defaultaddrpolicy VNET(defaultaddrpolicy)
127
128 VNET_DEFINE(int, ip6_prefer_tempaddr) = 0;
129
130 static int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *,
131 struct ip6_moptions *, struct route_in6 *, struct ifnet **,
132 struct nhop_object **, int, u_int, uint32_t);
133 static int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *,
134 struct ip6_moptions *, struct ifnet **,
135 struct ifnet *, u_int);
136 static int in6_selectsrc(uint32_t, struct sockaddr_in6 *,
137 struct ip6_pktopts *, struct inpcb *, struct ucred *,
138 struct ifnet **, struct in6_addr *);
139
140 static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *);
141
142 static void init_policy_queue(void);
143 static int add_addrsel_policyent(struct in6_addrpolicy *);
144 static int delete_addrsel_policyent(struct in6_addrpolicy *);
145 static int walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *),
146 void *);
147 static int dump_addrsel_policyent(struct in6_addrpolicy *, void *);
148 static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *);
149
150 /*
151 * Return an IPv6 address, which is the most appropriate for a given
152 * destination and user specified options.
153 * If necessary, this function lookups the routing table and returns
154 * an entry to the caller for later use.
155 */
156 #define REPLACE(r) do {\
157 IP6STAT_INC(ip6s_sources_rule[(r)]); \
158 /* { \
159 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
160 printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \
161 } */ \
162 goto replace; \
163 } while(0)
164 #define NEXT(r) do {\
165 /* { \
166 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
167 printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \
168 } */ \
169 goto next; /* XXX: we can't use 'continue' here */ \
170 } while(0)
171 #define BREAK(r) do { \
172 IP6STAT_INC(ip6s_sources_rule[(r)]); \
173 goto out; /* XXX: we can't use 'break' here */ \
174 } while(0)
175
176 static int
in6_selectsrc(uint32_t fibnum,struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct inpcb * inp,struct ucred * cred,struct ifnet ** ifpp,struct in6_addr * srcp)177 in6_selectsrc(uint32_t fibnum, struct sockaddr_in6 *dstsock,
178 struct ip6_pktopts *opts, struct inpcb *inp, struct ucred *cred,
179 struct ifnet **ifpp, struct in6_addr *srcp)
180 {
181 struct rm_priotracker in6_ifa_tracker;
182 struct in6_addr dst, tmp;
183 struct ifnet *ifp = NULL, *oifp = NULL;
184 struct in6_ifaddr *ia = NULL, *ia_best = NULL;
185 struct in6_pktinfo *pi = NULL;
186 int dst_scope = -1, best_scope = -1, best_matchlen = -1;
187 struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
188 u_int32_t odstzone;
189 int prefer_tempaddr;
190 int error;
191 struct ip6_moptions *mopts;
192
193 NET_EPOCH_ASSERT();
194 KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__));
195
196 dst = dstsock->sin6_addr; /* make a copy for local operation */
197 if (ifpp) {
198 /*
199 * Save a possibly passed in ifp for in6_selectsrc. Only
200 * neighbor discovery code should use this feature, where
201 * we may know the interface but not the FIB number holding
202 * the connected subnet in case someone deleted it from the
203 * default FIB and we need to check the interface.
204 */
205 if (*ifpp != NULL)
206 oifp = *ifpp;
207 *ifpp = NULL;
208 }
209
210 if (inp != NULL) {
211 INP_LOCK_ASSERT(inp);
212 mopts = inp->in6p_moptions;
213 } else {
214 mopts = NULL;
215 }
216
217 /*
218 * If the source address is explicitly specified by the caller,
219 * check if the requested source address is indeed a unicast address
220 * assigned to the node, and can be used as the packet's source
221 * address. If everything is okay, use the address as source.
222 */
223 if (opts && (pi = opts->ip6po_pktinfo) &&
224 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
225 /* get the outgoing interface */
226 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp,
227 fibnum))
228 != 0)
229 return (error);
230
231 /*
232 * determine the appropriate zone id of the source based on
233 * the zone of the destination and the outgoing interface.
234 * If the specified address is ambiguous wrt the scope zone,
235 * the interface must be specified; otherwise, ifa_ifwithaddr()
236 * will fail matching the address.
237 */
238 tmp = pi->ipi6_addr;
239 if (ifp) {
240 error = in6_setscope(&tmp, ifp, &odstzone);
241 if (error)
242 return (error);
243 }
244 if (cred != NULL && (error = prison_local_ip6(cred,
245 &tmp, (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0)
246 return (error);
247
248 /*
249 * If IPV6_BINDANY socket option is set, we allow to specify
250 * non local addresses as source address in IPV6_PKTINFO
251 * ancillary data.
252 */
253 if ((inp->inp_flags & INP_BINDANY) == 0) {
254 ia = in6ifa_ifwithaddr(&tmp, 0 /* XXX */, false);
255 if (ia == NULL || (ia->ia6_flags & (IN6_IFF_ANYCAST |
256 IN6_IFF_NOTREADY)))
257 return (EADDRNOTAVAIL);
258 bcopy(&ia->ia_addr.sin6_addr, srcp, sizeof(*srcp));
259 } else
260 bcopy(&tmp, srcp, sizeof(*srcp));
261 pi->ipi6_addr = tmp; /* XXX: this overrides pi */
262 if (ifpp)
263 *ifpp = ifp;
264 return (0);
265 }
266
267 /*
268 * Otherwise, if the socket has already bound the source, just use it.
269 */
270 if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
271 if (cred != NULL &&
272 (error = prison_local_ip6(cred, &inp->in6p_laddr,
273 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0)
274 return (error);
275 bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp));
276 return (0);
277 }
278
279 /*
280 * Bypass source address selection and use the primary jail IP
281 * if requested.
282 */
283 if (cred != NULL && !prison_saddrsel_ip6(cred, srcp))
284 return (0);
285
286 /*
287 * If the address is not specified, choose the best one based on
288 * the outgoing interface and the destination address.
289 */
290 /* get the outgoing interface */
291 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp,
292 (inp != NULL) ? inp->inp_inc.inc_fibnum : fibnum)) != 0)
293 return (error);
294
295 #ifdef DIAGNOSTIC
296 if (ifp == NULL) /* this should not happen */
297 panic("in6_selectsrc: NULL ifp");
298 #endif
299 error = in6_setscope(&dst, ifp, &odstzone);
300 if (error)
301 return (error);
302
303 IN6_IFADDR_RLOCK(&in6_ifa_tracker);
304 CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
305 int new_scope = -1, new_matchlen = -1;
306 struct in6_addrpolicy *new_policy = NULL;
307 u_int32_t srczone, osrczone, dstzone;
308 struct in6_addr src;
309 struct ifnet *ifp1 = ia->ia_ifp;
310
311 /*
312 * We'll never take an address that breaks the scope zone
313 * of the destination. We also skip an address if its zone
314 * does not contain the outgoing interface.
315 * XXX: we should probably use sin6_scope_id here.
316 */
317 if (in6_setscope(&dst, ifp1, &dstzone) ||
318 odstzone != dstzone) {
319 continue;
320 }
321 src = ia->ia_addr.sin6_addr;
322 if (in6_setscope(&src, ifp, &osrczone) ||
323 in6_setscope(&src, ifp1, &srczone) ||
324 osrczone != srczone) {
325 continue;
326 }
327
328 /* avoid unusable addresses */
329 if ((ia->ia6_flags &
330 (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) {
331 continue;
332 }
333 if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
334 continue;
335
336 /* If jailed only take addresses of the jail into account. */
337 if (cred != NULL &&
338 prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0)
339 continue;
340
341 /* Rule 1: Prefer same address */
342 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) {
343 ia_best = ia;
344 BREAK(1); /* there should be no better candidate */
345 }
346
347 if (ia_best == NULL)
348 REPLACE(0);
349
350 /* Rule 2: Prefer appropriate scope */
351 if (dst_scope < 0)
352 dst_scope = in6_addrscope(&dst);
353 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
354 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
355 if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
356 REPLACE(2);
357 NEXT(2);
358 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
359 if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
360 NEXT(2);
361 REPLACE(2);
362 }
363
364 /*
365 * Rule 3: Avoid deprecated addresses. Note that the case of
366 * !ip6_use_deprecated is already rejected above.
367 */
368 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
369 NEXT(3);
370 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
371 REPLACE(3);
372
373 /* Rule 4: Prefer home addresses */
374 /*
375 * XXX: This is a TODO. We should probably merge the MIP6
376 * case above.
377 */
378
379 /* Rule 5: Prefer outgoing interface */
380 if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) {
381 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
382 NEXT(5);
383 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
384 REPLACE(5);
385 }
386
387 /*
388 * Rule 6: Prefer matching label
389 * Note that best_policy should be non-NULL here.
390 */
391 if (dst_policy == NULL)
392 dst_policy = lookup_addrsel_policy(dstsock);
393 if (dst_policy->label != ADDR_LABEL_NOTAPP) {
394 new_policy = lookup_addrsel_policy(&ia->ia_addr);
395 if (dst_policy->label == best_policy->label &&
396 dst_policy->label != new_policy->label)
397 NEXT(6);
398 if (dst_policy->label != best_policy->label &&
399 dst_policy->label == new_policy->label)
400 REPLACE(6);
401 }
402
403 /*
404 * Rule 7: Prefer public addresses.
405 * We allow users to reverse the logic by configuring
406 * a sysctl variable, so that privacy conscious users can
407 * always prefer temporary addresses.
408 */
409 if (opts == NULL ||
410 opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) {
411 prefer_tempaddr = V_ip6_prefer_tempaddr;
412 } else if (opts->ip6po_prefer_tempaddr ==
413 IP6PO_TEMPADDR_NOTPREFER) {
414 prefer_tempaddr = 0;
415 } else
416 prefer_tempaddr = 1;
417 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
418 (ia->ia6_flags & IN6_IFF_TEMPORARY)) {
419 if (prefer_tempaddr)
420 REPLACE(7);
421 else
422 NEXT(7);
423 }
424 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
425 !(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
426 if (prefer_tempaddr)
427 NEXT(7);
428 else
429 REPLACE(7);
430 }
431
432 /*
433 * Rule 8: prefer addresses on alive interfaces.
434 * This is a KAME specific rule.
435 */
436 if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
437 !(ia->ia_ifp->if_flags & IFF_UP))
438 NEXT(8);
439 if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
440 (ia->ia_ifp->if_flags & IFF_UP))
441 REPLACE(8);
442
443 /*
444 * Rule 9: prefer address with better virtual status.
445 */
446 if (ifa_preferred(&ia_best->ia_ifa, &ia->ia_ifa))
447 REPLACE(9);
448 if (ifa_preferred(&ia->ia_ifa, &ia_best->ia_ifa))
449 NEXT(9);
450
451 /*
452 * Rule 10: prefer address with `prefer_source' flag.
453 */
454 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0 &&
455 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0)
456 REPLACE(10);
457 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0 &&
458 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0)
459 NEXT(10);
460
461 /*
462 * Rule 14: Use longest matching prefix.
463 * Note: in the address selection draft, this rule is
464 * documented as "Rule 8". However, since it is also
465 * documented that this rule can be overridden, we assign
466 * a large number so that it is easy to assign smaller numbers
467 * to more preferred rules.
468 */
469 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst);
470 if (best_matchlen < new_matchlen)
471 REPLACE(14);
472 if (new_matchlen < best_matchlen)
473 NEXT(14);
474
475 /* Rule 15 is reserved. */
476
477 /*
478 * Last resort: just keep the current candidate.
479 * Or, do we need more rules?
480 */
481 continue;
482
483 replace:
484 ia_best = ia;
485 best_scope = (new_scope >= 0 ? new_scope :
486 in6_addrscope(&ia_best->ia_addr.sin6_addr));
487 best_policy = (new_policy ? new_policy :
488 lookup_addrsel_policy(&ia_best->ia_addr));
489 best_matchlen = (new_matchlen >= 0 ? new_matchlen :
490 in6_matchlen(&ia_best->ia_addr.sin6_addr,
491 &dst));
492
493 next:
494 continue;
495
496 out:
497 break;
498 }
499
500 if ((ia = ia_best) == NULL) {
501 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
502 IP6STAT_INC(ip6s_sources_none);
503 return (EADDRNOTAVAIL);
504 }
505
506 /*
507 * At this point at least one of the addresses belonged to the jail
508 * but it could still be, that we want to further restrict it, e.g.
509 * theoratically IN6_IS_ADDR_LOOPBACK.
510 * It must not be IN6_IS_ADDR_UNSPECIFIED anymore.
511 * prison_local_ip6() will fix an IN6_IS_ADDR_LOOPBACK but should
512 * let all others previously selected pass.
513 * Use tmp to not change ::1 on lo0 to the primary jail address.
514 */
515 tmp = ia->ia_addr.sin6_addr;
516 if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL &&
517 (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) {
518 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
519 IP6STAT_INC(ip6s_sources_none);
520 return (EADDRNOTAVAIL);
521 }
522
523 if (ifpp)
524 *ifpp = ifp;
525
526 bcopy(&tmp, srcp, sizeof(*srcp));
527 if (ia->ia_ifp == ifp)
528 IP6STAT_INC(ip6s_sources_sameif[best_scope]);
529 else
530 IP6STAT_INC(ip6s_sources_otherif[best_scope]);
531 if (dst_scope == best_scope)
532 IP6STAT_INC(ip6s_sources_samescope[best_scope]);
533 else
534 IP6STAT_INC(ip6s_sources_otherscope[best_scope]);
535 if (IFA6_IS_DEPRECATED(ia))
536 IP6STAT_INC(ip6s_sources_deprecated[best_scope]);
537 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
538 return (0);
539 }
540
541 /*
542 * Select source address based on @inp, @dstsock and @opts.
543 * Stores selected address to @srcp. If @scope_ambiguous is set,
544 * embed scope from selected outgoing interface. If @hlim pointer
545 * is provided, stores calculated hop limit there.
546 * Returns 0 on success.
547 */
548 int
in6_selectsrc_socket(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct inpcb * inp,struct ucred * cred,int scope_ambiguous,struct in6_addr * srcp,int * hlim)549 in6_selectsrc_socket(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
550 struct inpcb *inp, struct ucred *cred, int scope_ambiguous,
551 struct in6_addr *srcp, int *hlim)
552 {
553 struct ifnet *retifp;
554 uint32_t fibnum;
555 int error;
556
557 fibnum = inp->inp_inc.inc_fibnum;
558 retifp = NULL;
559
560 error = in6_selectsrc(fibnum, dstsock, opts, inp, cred, &retifp, srcp);
561 if (error != 0)
562 return (error);
563
564 if (hlim != NULL)
565 *hlim = in6_selecthlim(inp, retifp);
566
567 if (retifp == NULL || scope_ambiguous == 0)
568 return (0);
569
570 /*
571 * Application should provide a proper zone ID or the use of
572 * default zone IDs should be enabled. Unfortunately, some
573 * applications do not behave as it should, so we need a
574 * workaround. Even if an appropriate ID is not determined
575 * (when it's required), if we can determine the outgoing
576 * interface. determine the zone ID based on the interface.
577 */
578 error = in6_setscope(&dstsock->sin6_addr, retifp, NULL);
579
580 return (error);
581 }
582
583 /*
584 * Select source address based on @fibnum, @dst and @scopeid.
585 * Stores selected address to @srcp.
586 * Returns 0 on success.
587 *
588 * Used by non-socket based consumers (ND code mostly)
589 */
590 int
in6_selectsrc_addr(uint32_t fibnum,const struct in6_addr * dst,uint32_t scopeid,struct ifnet * ifp,struct in6_addr * srcp,int * hlim)591 in6_selectsrc_addr(uint32_t fibnum, const struct in6_addr *dst,
592 uint32_t scopeid, struct ifnet *ifp, struct in6_addr *srcp,
593 int *hlim)
594 {
595 struct ifnet *retifp;
596 struct sockaddr_in6 dst_sa;
597 int error;
598
599 retifp = ifp;
600 bzero(&dst_sa, sizeof(dst_sa));
601 dst_sa.sin6_family = AF_INET6;
602 dst_sa.sin6_len = sizeof(dst_sa);
603 dst_sa.sin6_addr = *dst;
604 dst_sa.sin6_scope_id = scopeid;
605 sa6_embedscope(&dst_sa, 0);
606
607 error = in6_selectsrc(fibnum, &dst_sa, NULL, NULL, NULL, &retifp, srcp);
608 if (hlim != NULL)
609 *hlim = in6_selecthlim(NULL, retifp);
610
611 return (error);
612 }
613
614 static struct nhop_object *
cache_route(uint32_t fibnum,const struct sockaddr_in6 * dst,struct route_in6 * ro,uint32_t flowid)615 cache_route(uint32_t fibnum, const struct sockaddr_in6 *dst, struct route_in6 *ro,
616 uint32_t flowid)
617 {
618 /*
619 * Use a cached route if it exists and is valid, else try to allocate
620 * a new one. Note that we should check the address family of the
621 * cached destination, in case of sharing the cache with IPv4.
622 * Assumes that 'struct route_in6' is exclusively locked.
623 */
624 if (ro->ro_nh != NULL && (
625 !NH_IS_VALID(ro->ro_nh) || ro->ro_dst.sin6_family != AF_INET6 ||
626 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &dst->sin6_addr)))
627 RO_NHFREE(ro);
628
629 if (ro->ro_nh == NULL) {
630 ro->ro_dst = *dst;
631
632 const struct in6_addr *paddr;
633 struct in6_addr unscoped_addr;
634 uint32_t scopeid = 0;
635 if (IN6_IS_SCOPE_LINKLOCAL(&dst->sin6_addr)) {
636 in6_splitscope(&dst->sin6_addr, &unscoped_addr, &scopeid);
637 paddr = &unscoped_addr;
638 } else
639 paddr = &dst->sin6_addr;
640 ro->ro_nh = fib6_lookup(fibnum, paddr, scopeid, NHR_REF, flowid);
641 }
642 return (ro->ro_nh);
643 }
644
645 static struct nhop_object *
lookup_route(uint32_t fibnum,struct sockaddr_in6 * dst,struct route_in6 * ro,struct ip6_pktopts * opts,uint32_t flowid)646 lookup_route(uint32_t fibnum, struct sockaddr_in6 *dst, struct route_in6 *ro,
647 struct ip6_pktopts *opts, uint32_t flowid)
648 {
649 struct nhop_object *nh = NULL;
650
651 /*
652 * If the next hop address for the packet is specified by the caller,
653 * use it as the gateway.
654 */
655 if (opts && opts->ip6po_nexthop) {
656 struct route_in6 *ron = &opts->ip6po_nextroute;
657 struct sockaddr_in6 *sin6_next = satosin6(opts->ip6po_nexthop);
658
659 nh = cache_route(fibnum, sin6_next, ron, flowid);
660
661 /*
662 * The node identified by that address must be a
663 * neighbor of the sending host.
664 */
665 if (nh != NULL && (nh->nh_flags & NHF_GATEWAY) != 0)
666 nh = NULL;
667 } else if (ro != NULL) {
668 nh = cache_route(fibnum, dst, ro, flowid);
669 if (nh == NULL)
670 return (NULL);
671
672 /*
673 * Check if the outgoing interface conflicts with
674 * the interface specified by ipi6_ifindex (if specified).
675 */
676 struct in6_pktinfo *pi;
677 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
678 if (nh->nh_aifp->if_index != pi->ipi6_ifindex)
679 nh = NULL;
680 }
681 }
682
683 return (nh);
684 }
685
686 /*
687 * Finds outgoing nexthop or the outgoing interface for the
688 * @dstsock.
689 * Return 0 on success and stores the lookup result in @retnh and @retifp
690 */
691 static int
selectroute(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct route_in6 * ro,struct ifnet ** retifp,struct nhop_object ** retnh,int norouteok,u_int fibnum,uint32_t flowid)692 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
693 struct ip6_moptions *mopts, struct route_in6 *ro,
694 struct ifnet **retifp, struct nhop_object **retnh, int norouteok,
695 u_int fibnum, uint32_t flowid)
696 {
697 int error = 0;
698 struct ifnet *ifp = NULL;
699 struct in6_pktinfo *pi = NULL;
700 struct in6_addr *dst = &dstsock->sin6_addr;
701
702 /* If the caller specify the outgoing interface explicitly, use it. */
703 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
704 /* XXX boundary check is assumed to be already done. */
705 ifp = ifnet_byindex(pi->ipi6_ifindex);
706 if (ifp != NULL && (norouteok || IN6_IS_ADDR_MULTICAST(dst))) {
707 /*
708 * we do not have to check or get the route for
709 * multicast.
710 */
711 goto done;
712 } else
713 goto getroute;
714 }
715 /*
716 * If the destination address is a multicast address and the outgoing
717 * interface for the address is specified by the caller, use it.
718 */
719 if (IN6_IS_ADDR_MULTICAST(dst) &&
720 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) {
721 goto done; /* we do not need a route for multicast. */
722 }
723 /*
724 * If destination address is LLA or link- or node-local multicast,
725 * use it's embedded scope zone id to determine outgoing interface.
726 */
727 if (IN6_IS_ADDR_MC_LINKLOCAL(dst) ||
728 IN6_IS_ADDR_MC_NODELOCAL(dst)) {
729 uint32_t zoneid = ntohs(in6_getscope(dst));
730 if (zoneid > 0) {
731 ifp = in6_getlinkifnet(zoneid);
732 goto done;
733 }
734 }
735
736 getroute:;
737 struct nhop_object *nh = lookup_route(fibnum, dstsock, ro, opts, flowid);
738 if (nh != NULL) {
739 *retifp = nh->nh_aifp;
740 error = 0;
741 } else {
742 *retifp = NULL;
743 IP6STAT_INC(ip6s_noroute);
744 error = EHOSTUNREACH;
745 }
746 *retnh = nh;
747 return (error);
748
749 done:
750 if (ifp == NULL) {
751 /*
752 * This can happen if the caller did not pass a cached route
753 * nor any other hints. We treat this case an error.
754 */
755 error = EHOSTUNREACH;
756 }
757 if (error == EHOSTUNREACH)
758 IP6STAT_INC(ip6s_noroute);
759
760 *retifp = ifp;
761 *retnh = NULL;
762
763 return (error);
764 }
765
766 static int
in6_selectif(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct ifnet ** retifp,struct ifnet * oifp,u_int fibnum)767 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
768 struct ip6_moptions *mopts, struct ifnet **retifp,
769 struct ifnet *oifp, u_int fibnum)
770 {
771 int error;
772 struct route_in6 sro;
773 struct nhop_object *nh = NULL;
774 uint16_t nh_flags;
775
776 KASSERT(retifp != NULL, ("%s: retifp is NULL", __func__));
777
778 bzero(&sro, sizeof(sro));
779 nh_flags = 0;
780
781 error = selectroute(dstsock, opts, mopts, &sro, retifp, &nh, 1, fibnum, 0);
782
783 if (nh != NULL)
784 nh_flags = nh->nh_flags;
785 if (nh != NULL && nh == sro.ro_nh)
786 NH_FREE(nh);
787
788 if (error != 0) {
789 /* Help ND. See oifp comment in in6_selectsrc(). */
790 if (oifp != NULL && fibnum == RT_DEFAULT_FIB) {
791 *retifp = oifp;
792 error = 0;
793 }
794 return (error);
795 }
796
797 /*
798 * do not use a rejected or black hole route.
799 * XXX: this check should be done in the L2 output routine.
800 * However, if we skipped this check here, we'd see the following
801 * scenario:
802 * - install a rejected route for a scoped address prefix
803 * (like fe80::/10)
804 * - send a packet to a destination that matches the scoped prefix,
805 * with ambiguity about the scope zone.
806 * - pick the outgoing interface from the route, and disambiguate the
807 * scope zone with the interface.
808 * - ip6_output() would try to get another route with the "new"
809 * destination, which may be valid.
810 * - we'd see no error on output.
811 * Although this may not be very harmful, it should still be confusing.
812 * We thus reject the case here.
813 */
814
815 if (nh_flags & (NHF_REJECT | NHF_BLACKHOLE)) {
816 error = (nh_flags & NHF_HOST ? EHOSTUNREACH : ENETUNREACH);
817 return (error);
818 }
819
820 return (0);
821 }
822
823 /* Public wrapper function to selectroute(). */
824 int
in6_selectroute(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct route_in6 * ro,struct ifnet ** retifp,struct nhop_object ** retnh,u_int fibnum,uint32_t flowid)825 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
826 struct ip6_moptions *mopts, struct route_in6 *ro,
827 struct ifnet **retifp, struct nhop_object **retnh, u_int fibnum, uint32_t flowid)
828 {
829 MPASS(retifp != NULL);
830 MPASS(retnh != NULL);
831
832 return (selectroute(dstsock, opts, mopts, ro, retifp,
833 retnh, 0, fibnum, flowid));
834 }
835
836 /*
837 * Default hop limit selection. The precedence is as follows:
838 * 1. Hoplimit value specified via ioctl.
839 * 2. (If the outgoing interface is detected) the current
840 * hop limit of the interface specified by router advertisement.
841 * 3. The system default hoplimit.
842 */
843 int
in6_selecthlim(struct inpcb * inp,struct ifnet * ifp)844 in6_selecthlim(struct inpcb *inp, struct ifnet *ifp)
845 {
846
847 if (inp && inp->in6p_hops >= 0)
848 return (inp->in6p_hops);
849 else if (ifp)
850 return (ND_IFINFO(ifp)->chlim);
851 else if (inp && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
852 struct nhop_object *nh;
853 struct in6_addr dst;
854 uint32_t fibnum, scopeid;
855 int hlim;
856
857 fibnum = inp->inp_inc.inc_fibnum;
858 in6_splitscope(&inp->in6p_faddr, &dst, &scopeid);
859 nh = fib6_lookup(fibnum, &dst, scopeid, 0, 0);
860 if (nh != NULL) {
861 hlim = ND_IFINFO(nh->nh_ifp)->chlim;
862 return (hlim);
863 }
864 }
865 return (V_ip6_defhlim);
866 }
867
868 void
addrsel_policy_init(void)869 addrsel_policy_init(void)
870 {
871
872 init_policy_queue();
873
874 /* initialize the "last resort" policy */
875 bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy));
876 V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
877
878 if (!IS_DEFAULT_VNET(curvnet))
879 return;
880
881 ADDRSEL_LOCK_INIT();
882 ADDRSEL_SXLOCK_INIT();
883 }
884
885 static struct in6_addrpolicy *
lookup_addrsel_policy(struct sockaddr_in6 * key)886 lookup_addrsel_policy(struct sockaddr_in6 *key)
887 {
888 struct in6_addrpolicy *match = NULL;
889
890 ADDRSEL_LOCK();
891 match = match_addrsel_policy(key);
892
893 if (match == NULL)
894 match = &V_defaultaddrpolicy;
895 else
896 match->use++;
897 ADDRSEL_UNLOCK();
898
899 return (match);
900 }
901
902 /*
903 * Subroutines to manage the address selection policy table via sysctl.
904 */
905 struct walkarg {
906 struct sysctl_req *w_req;
907 };
908
909 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
910 SYSCTL_DECL(_net_inet6_ip6);
911 static SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
912 CTLFLAG_RD | CTLFLAG_MPSAFE, in6_src_sysctl,
913 "");
914
915 static int
in6_src_sysctl(SYSCTL_HANDLER_ARGS)916 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
917 {
918 struct walkarg w;
919
920 if (req->newptr)
921 return EPERM;
922
923 bzero(&w, sizeof(w));
924 w.w_req = req;
925
926 return (walk_addrsel_policy(dump_addrsel_policyent, &w));
927 }
928
929 int
in6_src_ioctl(u_long cmd,caddr_t data)930 in6_src_ioctl(u_long cmd, caddr_t data)
931 {
932 struct in6_addrpolicy ent0;
933
934 if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
935 return (EOPNOTSUPP); /* check for safety */
936
937 ent0 = *(struct in6_addrpolicy *)data;
938
939 if (ent0.label == ADDR_LABEL_NOTAPP)
940 return (EINVAL);
941 /* check if the prefix mask is consecutive. */
942 if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
943 return (EINVAL);
944 /* clear trailing garbages (if any) of the prefix address. */
945 IN6_MASK_ADDR(&ent0.addr.sin6_addr, &ent0.addrmask.sin6_addr);
946 ent0.use = 0;
947
948 switch (cmd) {
949 case SIOCAADDRCTL_POLICY:
950 return (add_addrsel_policyent(&ent0));
951 case SIOCDADDRCTL_POLICY:
952 return (delete_addrsel_policyent(&ent0));
953 }
954
955 return (0); /* XXX: compromise compilers */
956 }
957
958 /*
959 * The followings are implementation of the policy table using a
960 * simple tail queue.
961 * XXX such details should be hidden.
962 * XXX implementation using binary tree should be more efficient.
963 */
964 struct addrsel_policyent {
965 TAILQ_ENTRY(addrsel_policyent) ape_entry;
966 struct in6_addrpolicy ape_policy;
967 };
968
969 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
970
971 VNET_DEFINE_STATIC(struct addrsel_policyhead, addrsel_policytab);
972 #define V_addrsel_policytab VNET(addrsel_policytab)
973
974 static void
init_policy_queue(void)975 init_policy_queue(void)
976 {
977
978 TAILQ_INIT(&V_addrsel_policytab);
979 }
980
981 static int
add_addrsel_policyent(struct in6_addrpolicy * newpolicy)982 add_addrsel_policyent(struct in6_addrpolicy *newpolicy)
983 {
984 struct addrsel_policyent *new, *pol;
985
986 new = malloc(sizeof(*new), M_IFADDR,
987 M_WAITOK);
988 ADDRSEL_XLOCK();
989 ADDRSEL_LOCK();
990
991 /* duplication check */
992 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
993 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr,
994 &pol->ape_policy.addr.sin6_addr) &&
995 IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr,
996 &pol->ape_policy.addrmask.sin6_addr)) {
997 ADDRSEL_UNLOCK();
998 ADDRSEL_XUNLOCK();
999 free(new, M_IFADDR);
1000 return (EEXIST); /* or override it? */
1001 }
1002 }
1003
1004 bzero(new, sizeof(*new));
1005
1006 /* XXX: should validate entry */
1007 new->ape_policy = *newpolicy;
1008
1009 TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry);
1010 ADDRSEL_UNLOCK();
1011 ADDRSEL_XUNLOCK();
1012
1013 return (0);
1014 }
1015
1016 static int
delete_addrsel_policyent(struct in6_addrpolicy * key)1017 delete_addrsel_policyent(struct in6_addrpolicy *key)
1018 {
1019 struct addrsel_policyent *pol;
1020
1021 ADDRSEL_XLOCK();
1022 ADDRSEL_LOCK();
1023
1024 /* search for the entry in the table */
1025 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1026 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr,
1027 &pol->ape_policy.addr.sin6_addr) &&
1028 IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr,
1029 &pol->ape_policy.addrmask.sin6_addr)) {
1030 break;
1031 }
1032 }
1033 if (pol == NULL) {
1034 ADDRSEL_UNLOCK();
1035 ADDRSEL_XUNLOCK();
1036 return (ESRCH);
1037 }
1038
1039 TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry);
1040 ADDRSEL_UNLOCK();
1041 ADDRSEL_XUNLOCK();
1042 free(pol, M_IFADDR);
1043
1044 return (0);
1045 }
1046
1047 static int
walk_addrsel_policy(int (* callback)(struct in6_addrpolicy *,void *),void * w)1048 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *), void *w)
1049 {
1050 struct addrsel_policyent *pol;
1051 int error = 0;
1052
1053 ADDRSEL_SLOCK();
1054 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1055 if ((error = (*callback)(&pol->ape_policy, w)) != 0) {
1056 ADDRSEL_SUNLOCK();
1057 return (error);
1058 }
1059 }
1060 ADDRSEL_SUNLOCK();
1061 return (error);
1062 }
1063
1064 static int
dump_addrsel_policyent(struct in6_addrpolicy * pol,void * arg)1065 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg)
1066 {
1067 int error = 0;
1068 struct walkarg *w = arg;
1069
1070 error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
1071
1072 return (error);
1073 }
1074
1075 static struct in6_addrpolicy *
match_addrsel_policy(struct sockaddr_in6 * key)1076 match_addrsel_policy(struct sockaddr_in6 *key)
1077 {
1078 struct addrsel_policyent *pent;
1079 struct in6_addrpolicy *bestpol = NULL, *pol;
1080 int matchlen, bestmatchlen = -1;
1081 u_char *mp, *ep, *k, *p, m;
1082
1083 TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) {
1084 matchlen = 0;
1085
1086 pol = &pent->ape_policy;
1087 mp = (u_char *)&pol->addrmask.sin6_addr;
1088 ep = mp + 16; /* XXX: scope field? */
1089 k = (u_char *)&key->sin6_addr;
1090 p = (u_char *)&pol->addr.sin6_addr;
1091 for (; mp < ep && *mp; mp++, k++, p++) {
1092 m = *mp;
1093 if ((*k & m) != *p)
1094 goto next; /* not match */
1095 if (m == 0xff) /* short cut for a typical case */
1096 matchlen += 8;
1097 else {
1098 while (m >= 0x80) {
1099 matchlen++;
1100 m <<= 1;
1101 }
1102 }
1103 }
1104
1105 /* matched. check if this is better than the current best. */
1106 if (bestpol == NULL ||
1107 matchlen > bestmatchlen) {
1108 bestpol = pol;
1109 bestmatchlen = matchlen;
1110 }
1111
1112 next:
1113 continue;
1114 }
1115
1116 return (bestpol);
1117 }
1118