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
63 #include <sys/cdefs.h>
64 #include "opt_inet.h"
65 #include "opt_inet6.h"
66 #include <sys/param.h>
67 #include <sys/systm.h>
68 #include <sys/lock.h>
69 #include <sys/malloc.h>
70 #include <sys/mbuf.h>
71 #include <sys/priv.h>
72 #include <sys/protosw.h>
73 #include <sys/socket.h>
74 #include <sys/socketvar.h>
75 #include <sys/sockio.h>
76 #include <sys/sysctl.h>
77 #include <sys/errno.h>
78 #include <sys/time.h>
79 #include <sys/jail.h>
80 #include <sys/kernel.h>
81 #include <sys/rmlock.h>
82 #include <sys/sx.h>
83
84 #include <net/if.h>
85 #include <net/if_var.h>
86 #include <net/if_dl.h>
87 #include <net/if_private.h>
88 #include <net/route.h>
89 #include <net/route/nhop.h>
90 #include <net/if_llatbl.h>
91
92 #include <netinet/in.h>
93 #include <netinet/in_var.h>
94 #include <netinet/in_systm.h>
95 #include <netinet/ip.h>
96 #include <netinet/in_pcb.h>
97 #include <netinet/ip_var.h>
98 #include <netinet/udp.h>
99 #include <netinet/udp_var.h>
100
101 #include <netinet6/in6_var.h>
102 #include <netinet/ip6.h>
103 #include <netinet6/in6_fib.h>
104 #include <netinet6/in6_pcb.h>
105 #include <netinet6/ip6_var.h>
106 #include <netinet6/scope6_var.h>
107 #include <netinet6/nd6.h>
108
109 static struct mtx addrsel_lock;
110 #define ADDRSEL_LOCK_INIT() mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF)
111 #define ADDRSEL_LOCK() mtx_lock(&addrsel_lock)
112 #define ADDRSEL_UNLOCK() mtx_unlock(&addrsel_lock)
113 #define ADDRSEL_LOCK_ASSERT() mtx_assert(&addrsel_lock, MA_OWNED)
114
115 static struct sx addrsel_sxlock;
116 #define ADDRSEL_SXLOCK_INIT() sx_init(&addrsel_sxlock, "addrsel_sxlock")
117 #define ADDRSEL_SLOCK() sx_slock(&addrsel_sxlock)
118 #define ADDRSEL_SUNLOCK() sx_sunlock(&addrsel_sxlock)
119 #define ADDRSEL_XLOCK() sx_xlock(&addrsel_sxlock)
120 #define ADDRSEL_XUNLOCK() sx_xunlock(&addrsel_sxlock)
121
122 #define ADDR_LABEL_NOTAPP (-1)
123 VNET_DEFINE_STATIC(struct in6_addrpolicy, defaultaddrpolicy);
124 #define V_defaultaddrpolicy VNET(defaultaddrpolicy)
125
126 VNET_DEFINE(int, ip6_prefer_tempaddr) = 0;
127
128 static int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *,
129 struct ip6_moptions *, struct route_in6 *, struct ifnet **,
130 struct nhop_object **, int, u_int, uint32_t);
131 static int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *,
132 struct ip6_moptions *, struct ifnet **,
133 struct ifnet *, u_int);
134 static int in6_selectsrc(uint32_t, struct sockaddr_in6 *,
135 struct ip6_pktopts *, struct ip6_moptions *, struct inpcb *,
136 struct ucred *, struct ifnet **, struct in6_addr *);
137
138 static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *);
139
140 static void init_policy_queue(void);
141 static int add_addrsel_policyent(struct in6_addrpolicy *);
142 static int delete_addrsel_policyent(struct in6_addrpolicy *);
143 static int walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *),
144 void *);
145 static int dump_addrsel_policyent(struct in6_addrpolicy *, void *);
146 static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *);
147
148 /*
149 * Return an IPv6 address, which is the most appropriate for a given
150 * destination and user specified options.
151 * If necessary, this function lookups the routing table and returns
152 * an entry to the caller for later use.
153 */
154 #define REPLACE(r) do {\
155 IP6STAT_INC2(ip6s_sources_rule, (r)); \
156 /* { \
157 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
158 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)); \
159 } */ \
160 goto replace; \
161 } while(0)
162 #define NEXT(r) do {\
163 /* { \
164 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
165 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)); \
166 } */ \
167 goto next; /* XXX: we can't use 'continue' here */ \
168 } while(0)
169 #define BREAK(r) do { \
170 IP6STAT_INC2(ip6s_sources_rule, (r)); \
171 goto out; /* XXX: we can't use 'break' here */ \
172 } while(0)
173
174 static int
in6_selectsrc(uint32_t fibnum,struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct inpcb * inp,struct ucred * cred,struct ifnet ** ifpp,struct in6_addr * srcp)175 in6_selectsrc(uint32_t fibnum, struct sockaddr_in6 *dstsock,
176 struct ip6_pktopts *opts, struct ip6_moptions *mopts, struct inpcb *inp,
177 struct ucred *cred, struct ifnet **ifpp, struct in6_addr *srcp)
178 {
179 struct rm_priotracker in6_ifa_tracker;
180 struct in6_addr dst, tmp;
181 struct ifnet *ifp = NULL, *oifp = NULL;
182 struct in6_ifaddr *ia = NULL, *ia_best = NULL;
183 struct in6_pktinfo *pi = NULL;
184 int dst_scope = -1, best_scope = -1, best_matchlen = -1;
185 struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
186 u_int32_t odstzone;
187 int prefer_tempaddr;
188 int error;
189
190 NET_EPOCH_ASSERT();
191 KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__));
192
193 dst = dstsock->sin6_addr; /* make a copy for local operation */
194 if (ifpp) {
195 /*
196 * Save a possibly passed in ifp for in6_selectsrc. Only
197 * neighbor discovery code should use this feature, where
198 * we may know the interface but not the FIB number holding
199 * the connected subnet in case someone deleted it from the
200 * default FIB and we need to check the interface.
201 */
202 if (*ifpp != NULL)
203 oifp = *ifpp;
204 *ifpp = NULL;
205 }
206
207 /*
208 * If the source address is explicitly specified by the caller,
209 * check if the requested source address is indeed a unicast address
210 * assigned to the node, and can be used as the packet's source
211 * address. If everything is okay, use the address as source.
212 */
213 if (opts && (pi = opts->ip6po_pktinfo) &&
214 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
215 /* get the outgoing interface */
216 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp,
217 fibnum))
218 != 0)
219 return (error);
220
221 /*
222 * determine the appropriate zone id of the source based on
223 * the zone of the destination and the outgoing interface.
224 * If the specified address is ambiguous wrt the scope zone,
225 * the interface must be specified; otherwise, ifa_ifwithaddr()
226 * will fail matching the address.
227 */
228 tmp = pi->ipi6_addr;
229 if (ifp) {
230 error = in6_setscope(&tmp, ifp, &odstzone);
231 if (error)
232 return (error);
233 }
234 if (cred != NULL && (error = prison_local_ip6(cred,
235 &tmp, (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0)
236 return (error);
237
238 /*
239 * If IPV6_BINDANY socket option is set, we allow to specify
240 * non local addresses as source address in IPV6_PKTINFO
241 * ancillary data.
242 */
243 if ((inp->inp_flags & INP_BINDANY) == 0) {
244 ia = in6ifa_ifwithaddr(&tmp, 0 /* XXX */, false);
245 if (ia == NULL || (ia->ia6_flags & (IN6_IFF_ANYCAST |
246 IN6_IFF_NOTREADY)))
247 return (EADDRNOTAVAIL);
248 bcopy(&ia->ia_addr.sin6_addr, srcp, sizeof(*srcp));
249 } else
250 bcopy(&tmp, srcp, sizeof(*srcp));
251 pi->ipi6_addr = tmp; /* XXX: this overrides pi */
252 if (ifpp)
253 *ifpp = ifp;
254 return (0);
255 }
256
257 /*
258 * Otherwise, if the socket has already bound the source, just use it.
259 */
260 if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
261 if (cred != NULL &&
262 (error = prison_local_ip6(cred, &inp->in6p_laddr,
263 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0)
264 return (error);
265 bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp));
266 return (0);
267 }
268
269 /*
270 * Bypass source address selection and use the primary jail IP
271 * if requested.
272 */
273 if (cred != NULL && !prison_saddrsel_ip6(cred, srcp))
274 return (0);
275
276 /*
277 * If the address is not specified, choose the best one based on
278 * the outgoing interface and the destination address.
279 */
280 /* get the outgoing interface */
281 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp,
282 (inp != NULL) ? inp->inp_inc.inc_fibnum : fibnum)) != 0)
283 return (error);
284
285 #ifdef DIAGNOSTIC
286 if (ifp == NULL) /* this should not happen */
287 panic("in6_selectsrc: NULL ifp");
288 #endif
289 error = in6_setscope(&dst, ifp, &odstzone);
290 if (error)
291 return (error);
292
293 IN6_IFADDR_RLOCK(&in6_ifa_tracker);
294 CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
295 int new_scope = -1, new_matchlen = -1;
296 struct in6_addrpolicy *new_policy = NULL;
297 u_int32_t srczone, osrczone, dstzone;
298 struct in6_addr src;
299 struct ifnet *ifp1 = ia->ia_ifp;
300
301 /*
302 * We'll never take an address that breaks the scope zone
303 * of the destination. We also skip an address if its zone
304 * does not contain the outgoing interface.
305 * XXX: we should probably use sin6_scope_id here.
306 */
307 if (in6_setscope(&dst, ifp1, &dstzone) ||
308 odstzone != dstzone) {
309 continue;
310 }
311 src = ia->ia_addr.sin6_addr;
312 if (in6_setscope(&src, ifp, &osrczone) ||
313 in6_setscope(&src, ifp1, &srczone) ||
314 osrczone != srczone) {
315 continue;
316 }
317
318 /* avoid unusable addresses */
319 if ((ia->ia6_flags &
320 (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) {
321 continue;
322 }
323 if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
324 continue;
325
326 /* If jailed only take addresses of the jail into account. */
327 if (cred != NULL &&
328 prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0)
329 continue;
330
331 /* Rule 1: Prefer same address */
332 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) {
333 ia_best = ia;
334 BREAK(1); /* there should be no better candidate */
335 }
336
337 if (ia_best == NULL)
338 REPLACE(0);
339
340 /* Rule 2: Prefer appropriate scope */
341 if (dst_scope < 0)
342 dst_scope = in6_addrscope(&dst);
343 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
344 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
345 if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
346 REPLACE(2);
347 NEXT(2);
348 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
349 if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
350 NEXT(2);
351 REPLACE(2);
352 }
353
354 /*
355 * Rule 3: Avoid deprecated addresses. Note that the case of
356 * !ip6_use_deprecated is already rejected above.
357 */
358 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
359 NEXT(3);
360 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
361 REPLACE(3);
362
363 /* Rule 4: Prefer home addresses */
364 /*
365 * XXX: This is a TODO. We should probably merge the MIP6
366 * case above.
367 */
368
369 /* Rule 5: Prefer outgoing interface */
370 if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) {
371 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
372 NEXT(5);
373 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
374 REPLACE(5);
375 }
376
377 /*
378 * Rule 6: Prefer matching label
379 * Note that best_policy should be non-NULL here.
380 */
381 if (dst_policy == NULL)
382 dst_policy = lookup_addrsel_policy(dstsock);
383 if (dst_policy->label != ADDR_LABEL_NOTAPP) {
384 new_policy = lookup_addrsel_policy(&ia->ia_addr);
385 if (dst_policy->label == best_policy->label &&
386 dst_policy->label != new_policy->label)
387 NEXT(6);
388 if (dst_policy->label != best_policy->label &&
389 dst_policy->label == new_policy->label)
390 REPLACE(6);
391 }
392
393 /*
394 * Rule 7: Prefer public addresses.
395 * We allow users to reverse the logic by configuring
396 * a sysctl variable, so that privacy conscious users can
397 * always prefer temporary addresses.
398 */
399 if (opts == NULL ||
400 opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) {
401 prefer_tempaddr = V_ip6_prefer_tempaddr;
402 } else if (opts->ip6po_prefer_tempaddr ==
403 IP6PO_TEMPADDR_NOTPREFER) {
404 prefer_tempaddr = 0;
405 } else
406 prefer_tempaddr = 1;
407 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
408 (ia->ia6_flags & IN6_IFF_TEMPORARY)) {
409 if (prefer_tempaddr)
410 REPLACE(7);
411 else
412 NEXT(7);
413 }
414 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
415 !(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
416 if (prefer_tempaddr)
417 NEXT(7);
418 else
419 REPLACE(7);
420 }
421
422 /*
423 * Rule 8: prefer addresses on alive interfaces.
424 * This is a KAME specific rule.
425 */
426 if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
427 !(ia->ia_ifp->if_flags & IFF_UP))
428 NEXT(8);
429 if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
430 (ia->ia_ifp->if_flags & IFF_UP))
431 REPLACE(8);
432
433 /*
434 * Rule 9: prefer address with better virtual status.
435 */
436 if (ifa_preferred(&ia_best->ia_ifa, &ia->ia_ifa))
437 REPLACE(9);
438 if (ifa_preferred(&ia->ia_ifa, &ia_best->ia_ifa))
439 NEXT(9);
440
441 /*
442 * Rule 10: prefer address with `prefer_source' flag.
443 */
444 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0 &&
445 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0)
446 REPLACE(10);
447 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0 &&
448 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0)
449 NEXT(10);
450
451 /*
452 * Rule 14: Use longest matching prefix.
453 * Note: in the address selection draft, this rule is
454 * documented as "Rule 8". However, since it is also
455 * documented that this rule can be overridden, we assign
456 * a large number so that it is easy to assign smaller numbers
457 * to more preferred rules.
458 */
459 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst);
460 if (best_matchlen < new_matchlen)
461 REPLACE(14);
462 if (new_matchlen < best_matchlen)
463 NEXT(14);
464
465 /* Rule 15 is reserved. */
466
467 /*
468 * Last resort: just keep the current candidate.
469 * Or, do we need more rules?
470 */
471 continue;
472
473 replace:
474 ia_best = ia;
475 best_scope = (new_scope >= 0 ? new_scope :
476 in6_addrscope(&ia_best->ia_addr.sin6_addr));
477 best_policy = (new_policy ? new_policy :
478 lookup_addrsel_policy(&ia_best->ia_addr));
479 best_matchlen = (new_matchlen >= 0 ? new_matchlen :
480 in6_matchlen(&ia_best->ia_addr.sin6_addr,
481 &dst));
482
483 next:
484 continue;
485
486 out:
487 break;
488 }
489
490 if ((ia = ia_best) == NULL) {
491 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
492 IP6STAT_INC(ip6s_sources_none);
493 return (EADDRNOTAVAIL);
494 }
495
496 /*
497 * At this point at least one of the addresses belonged to the jail
498 * but it could still be, that we want to further restrict it, e.g.
499 * theoratically IN6_IS_ADDR_LOOPBACK.
500 * It must not be IN6_IS_ADDR_UNSPECIFIED anymore.
501 * prison_local_ip6() will fix an IN6_IS_ADDR_LOOPBACK but should
502 * let all others previously selected pass.
503 * Use tmp to not change ::1 on lo0 to the primary jail address.
504 */
505 tmp = ia->ia_addr.sin6_addr;
506 if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL &&
507 (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) {
508 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
509 IP6STAT_INC(ip6s_sources_none);
510 return (EADDRNOTAVAIL);
511 }
512
513 if (ifpp)
514 *ifpp = ifp;
515
516 bcopy(&tmp, srcp, sizeof(*srcp));
517 if (ia->ia_ifp == ifp)
518 IP6STAT_INC2(ip6s_sources_sameif, best_scope);
519 else
520 IP6STAT_INC2(ip6s_sources_otherif, best_scope);
521 if (dst_scope == best_scope)
522 IP6STAT_INC2(ip6s_sources_samescope, best_scope);
523 else
524 IP6STAT_INC2(ip6s_sources_otherscope, best_scope);
525 if (IFA6_IS_DEPRECATED(ia))
526 IP6STAT_INC2(ip6s_sources_deprecated, best_scope);
527 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
528 return (0);
529 }
530
531 /*
532 * Select source address based on @inp, @dstsock and @opts.
533 * Stores selected address to @srcp. If @scope_ambiguous is set,
534 * embed scope from selected outgoing interface. If @hlim pointer
535 * is provided, stores calculated hop limit there.
536 * Returns 0 on success.
537 */
538 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)539 in6_selectsrc_socket(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
540 struct inpcb *inp, struct ucred *cred, int scope_ambiguous,
541 struct in6_addr *srcp, int *hlim)
542 {
543 struct ifnet *retifp;
544 uint32_t fibnum;
545 int error;
546
547 INP_LOCK_ASSERT(inp);
548
549 fibnum = inp->inp_inc.inc_fibnum;
550 retifp = NULL;
551
552 error = in6_selectsrc(fibnum, dstsock, opts, inp->in6p_moptions,
553 inp, cred, &retifp, srcp);
554 if (error != 0)
555 return (error);
556
557 if (hlim != NULL)
558 *hlim = in6_selecthlim(inp, retifp);
559
560 if (retifp == NULL || scope_ambiguous == 0)
561 return (0);
562
563 /*
564 * Application should provide a proper zone ID or the use of
565 * default zone IDs should be enabled. Unfortunately, some
566 * applications do not behave as it should, so we need a
567 * workaround. Even if an appropriate ID is not determined
568 * (when it's required), if we can determine the outgoing
569 * interface. determine the zone ID based on the interface.
570 */
571 error = in6_setscope(&dstsock->sin6_addr, retifp, NULL);
572
573 return (error);
574 }
575
576 /*
577 * Select source address based on @fibnum, @dst and @scopeid.
578 * Stores selected address to @srcp.
579 * Returns 0 on success.
580 *
581 * Used by non-socket based consumers
582 */
583 int
in6_selectsrc_addr(uint32_t fibnum,const struct in6_addr * dst,uint32_t scopeid,struct ifnet * ifp,struct in6_addr * srcp,int * hlim)584 in6_selectsrc_addr(uint32_t fibnum, const struct in6_addr *dst,
585 uint32_t scopeid, struct ifnet *ifp, struct in6_addr *srcp,
586 int *hlim)
587 {
588 struct ifnet *retifp;
589 struct sockaddr_in6 dst_sa;
590 int error;
591
592 retifp = ifp;
593 bzero(&dst_sa, sizeof(dst_sa));
594 dst_sa.sin6_family = AF_INET6;
595 dst_sa.sin6_len = sizeof(dst_sa);
596 dst_sa.sin6_addr = *dst;
597 dst_sa.sin6_scope_id = scopeid;
598 sa6_embedscope(&dst_sa, 0);
599
600 error = in6_selectsrc(fibnum, &dst_sa, NULL, NULL,
601 NULL, NULL, &retifp, srcp);
602 if (hlim != NULL)
603 *hlim = in6_selecthlim(NULL, retifp);
604
605 return (error);
606 }
607
608 /*
609 * Select source address based on @fibnum, @dst and @mopts.
610 * Stores selected address to @srcp.
611 * Returns 0 on success.
612 *
613 * Used by non-socket based consumers (ND code mostly)
614 */
615 int
in6_selectsrc_nbr(uint32_t fibnum,const struct in6_addr * dst,struct ip6_moptions * mopts,struct ifnet * ifp,struct in6_addr * srcp)616 in6_selectsrc_nbr(uint32_t fibnum, const struct in6_addr *dst,
617 struct ip6_moptions *mopts, struct ifnet *ifp, struct in6_addr *srcp)
618 {
619 struct sockaddr_in6 dst_sa;
620 struct ifnet *retifp;
621 int error;
622
623 retifp = ifp;
624 bzero(&dst_sa, sizeof(dst_sa));
625 dst_sa.sin6_family = AF_INET6;
626 dst_sa.sin6_len = sizeof(dst_sa);
627 dst_sa.sin6_addr = *dst;
628 dst_sa.sin6_scope_id = ntohs(in6_getscope(dst));
629 sa6_embedscope(&dst_sa, 0);
630
631 error = in6_selectsrc(fibnum, &dst_sa, NULL, mopts,
632 NULL, NULL, &retifp, srcp);
633 return (error);
634 }
635
636 static struct nhop_object *
cache_route(uint32_t fibnum,const struct sockaddr_in6 * dst,struct route_in6 * ro,uint32_t flowid)637 cache_route(uint32_t fibnum, const struct sockaddr_in6 *dst, struct route_in6 *ro,
638 uint32_t flowid)
639 {
640 /*
641 * Use a cached route if it exists and is valid, else try to allocate
642 * a new one. Note that we should check the address family of the
643 * cached destination, in case of sharing the cache with IPv4.
644 * Assumes that 'struct route_in6' is exclusively locked.
645 */
646 if (ro->ro_nh != NULL && (
647 !NH_IS_VALID(ro->ro_nh) || ro->ro_dst.sin6_family != AF_INET6 ||
648 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &dst->sin6_addr)))
649 RO_NHFREE(ro);
650
651 if (ro->ro_nh == NULL) {
652 ro->ro_dst = *dst;
653
654 const struct in6_addr *paddr;
655 struct in6_addr unscoped_addr;
656 uint32_t scopeid = 0;
657 if (IN6_IS_SCOPE_LINKLOCAL(&dst->sin6_addr)) {
658 in6_splitscope(&dst->sin6_addr, &unscoped_addr, &scopeid);
659 paddr = &unscoped_addr;
660 } else
661 paddr = &dst->sin6_addr;
662 ro->ro_nh = fib6_lookup(fibnum, paddr, scopeid, NHR_REF, flowid);
663 }
664 return (ro->ro_nh);
665 }
666
667 static struct nhop_object *
lookup_route(uint32_t fibnum,struct sockaddr_in6 * dst,struct route_in6 * ro,struct ip6_pktopts * opts,uint32_t flowid)668 lookup_route(uint32_t fibnum, struct sockaddr_in6 *dst, struct route_in6 *ro,
669 struct ip6_pktopts *opts, uint32_t flowid)
670 {
671 struct nhop_object *nh = NULL;
672
673 /*
674 * If the next hop address for the packet is specified by the caller,
675 * use it as the gateway.
676 */
677 if (opts && opts->ip6po_nexthop) {
678 struct route_in6 *ron = &opts->ip6po_nextroute;
679 struct sockaddr_in6 *sin6_next = satosin6(opts->ip6po_nexthop);
680
681 nh = cache_route(fibnum, sin6_next, ron, flowid);
682
683 /*
684 * The node identified by that address must be a
685 * neighbor of the sending host.
686 */
687 if (nh != NULL && (nh->nh_flags & NHF_GATEWAY) != 0)
688 nh = NULL;
689 } else if (ro != NULL) {
690 nh = cache_route(fibnum, dst, ro, flowid);
691 if (nh == NULL)
692 return (NULL);
693
694 /*
695 * Check if the outgoing interface conflicts with
696 * the interface specified by ipi6_ifindex (if specified).
697 */
698 struct in6_pktinfo *pi;
699 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
700 if (nh->nh_aifp->if_index != pi->ipi6_ifindex)
701 nh = NULL;
702 }
703 }
704
705 return (nh);
706 }
707
708 /*
709 * Finds outgoing nexthop or the outgoing interface for the
710 * @dstsock.
711 * Return 0 on success and stores the lookup result in @retnh and @retifp
712 */
713 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)714 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
715 struct ip6_moptions *mopts, struct route_in6 *ro,
716 struct ifnet **retifp, struct nhop_object **retnh, int norouteok,
717 u_int fibnum, uint32_t flowid)
718 {
719 int error = 0;
720 struct ifnet *ifp = NULL;
721 struct in6_pktinfo *pi = NULL;
722 struct in6_addr *dst = &dstsock->sin6_addr;
723
724 /* If the caller specify the outgoing interface explicitly, use it. */
725 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
726 /* XXX boundary check is assumed to be already done. */
727 ifp = ifnet_byindex(pi->ipi6_ifindex);
728 if (ifp != NULL && (norouteok || IN6_IS_ADDR_MULTICAST(dst))) {
729 /*
730 * we do not have to check or get the route for
731 * multicast.
732 */
733 goto done;
734 } else
735 goto getroute;
736 }
737 /*
738 * If the destination address is a multicast address and the outgoing
739 * interface for the address is specified by the caller, use it.
740 */
741 if (IN6_IS_ADDR_MULTICAST(dst) &&
742 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) {
743 goto done; /* we do not need a route for multicast. */
744 }
745 /*
746 * If destination address is LLA or link- or node-local multicast,
747 * use it's embedded scope zone id to determine outgoing interface.
748 */
749 if (IN6_IS_ADDR_MC_LINKLOCAL(dst) ||
750 IN6_IS_ADDR_MC_NODELOCAL(dst)) {
751 uint32_t zoneid = ntohs(in6_getscope(dst));
752 if (zoneid > 0) {
753 ifp = in6_getlinkifnet(zoneid);
754 goto done;
755 }
756 }
757
758 getroute:;
759 struct nhop_object *nh = lookup_route(fibnum, dstsock, ro, opts, flowid);
760 if (nh != NULL) {
761 *retifp = nh->nh_aifp;
762 error = 0;
763 } else {
764 *retifp = NULL;
765 IP6STAT_INC(ip6s_noroute);
766 error = EHOSTUNREACH;
767 }
768 *retnh = nh;
769 return (error);
770
771 done:
772 if (ifp == NULL) {
773 /*
774 * This can happen if the caller did not pass a cached route
775 * nor any other hints. We treat this case an error.
776 */
777 error = EHOSTUNREACH;
778 }
779 if (error == EHOSTUNREACH)
780 IP6STAT_INC(ip6s_noroute);
781
782 *retifp = ifp;
783 *retnh = NULL;
784
785 return (error);
786 }
787
788 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)789 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
790 struct ip6_moptions *mopts, struct ifnet **retifp,
791 struct ifnet *oifp, u_int fibnum)
792 {
793 int error;
794 struct route_in6 sro;
795 struct nhop_object *nh = NULL;
796 uint16_t nh_flags;
797
798 KASSERT(retifp != NULL, ("%s: retifp is NULL", __func__));
799
800 bzero(&sro, sizeof(sro));
801 nh_flags = 0;
802
803 error = selectroute(dstsock, opts, mopts, &sro, retifp, &nh, 1, fibnum, 0);
804
805 if (nh != NULL)
806 nh_flags = nh->nh_flags;
807 if (nh != NULL && nh == sro.ro_nh)
808 NH_FREE(nh);
809
810 if (error != 0) {
811 /* Help ND. See oifp comment in in6_selectsrc(). */
812 if (oifp != NULL && fibnum == RT_DEFAULT_FIB) {
813 *retifp = oifp;
814 error = 0;
815 }
816 return (error);
817 }
818
819 /*
820 * do not use a rejected or black hole route.
821 * XXX: this check should be done in the L2 output routine.
822 * However, if we skipped this check here, we'd see the following
823 * scenario:
824 * - install a rejected route for a scoped address prefix
825 * (like fe80::/10)
826 * - send a packet to a destination that matches the scoped prefix,
827 * with ambiguity about the scope zone.
828 * - pick the outgoing interface from the route, and disambiguate the
829 * scope zone with the interface.
830 * - ip6_output() would try to get another route with the "new"
831 * destination, which may be valid.
832 * - we'd see no error on output.
833 * Although this may not be very harmful, it should still be confusing.
834 * We thus reject the case here.
835 */
836
837 if (nh_flags & (NHF_REJECT | NHF_BLACKHOLE)) {
838 error = (nh_flags & NHF_HOST ? EHOSTUNREACH : ENETUNREACH);
839 return (error);
840 }
841
842 return (0);
843 }
844
845 /* Public wrapper function to selectroute(). */
846 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)847 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
848 struct ip6_moptions *mopts, struct route_in6 *ro,
849 struct ifnet **retifp, struct nhop_object **retnh, u_int fibnum, uint32_t flowid)
850 {
851 MPASS(retifp != NULL);
852 MPASS(retnh != NULL);
853
854 return (selectroute(dstsock, opts, mopts, ro, retifp,
855 retnh, 0, fibnum, flowid));
856 }
857
858 /*
859 * Default hop limit selection. The precedence is as follows:
860 * 1. Hoplimit value specified via ioctl.
861 * 2. (If the outgoing interface is detected) the current
862 * hop limit of the interface specified by router advertisement.
863 * 3. The system default hoplimit.
864 */
865 int
in6_selecthlim(struct inpcb * inp,struct ifnet * ifp)866 in6_selecthlim(struct inpcb *inp, struct ifnet *ifp)
867 {
868
869 if (inp && inp->in6p_hops >= 0)
870 return (inp->in6p_hops);
871 else if (ifp)
872 return (ND_IFINFO(ifp)->chlim);
873 else if (inp && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
874 struct nhop_object *nh;
875 struct in6_addr dst;
876 uint32_t fibnum, scopeid;
877 int hlim;
878
879 fibnum = inp->inp_inc.inc_fibnum;
880 in6_splitscope(&inp->in6p_faddr, &dst, &scopeid);
881 nh = fib6_lookup(fibnum, &dst, scopeid, 0, 0);
882 if (nh != NULL) {
883 hlim = ND_IFINFO(nh->nh_ifp)->chlim;
884 return (hlim);
885 }
886 }
887 return (V_ip6_defhlim);
888 }
889
890 void
addrsel_policy_init(void)891 addrsel_policy_init(void)
892 {
893
894 init_policy_queue();
895
896 /* initialize the "last resort" policy */
897 bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy));
898 V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
899
900 if (!IS_DEFAULT_VNET(curvnet))
901 return;
902
903 ADDRSEL_LOCK_INIT();
904 ADDRSEL_SXLOCK_INIT();
905 }
906
907 static struct in6_addrpolicy *
lookup_addrsel_policy(struct sockaddr_in6 * key)908 lookup_addrsel_policy(struct sockaddr_in6 *key)
909 {
910 struct in6_addrpolicy *match = NULL;
911
912 ADDRSEL_LOCK();
913 match = match_addrsel_policy(key);
914
915 if (match == NULL)
916 match = &V_defaultaddrpolicy;
917 else
918 match->use++;
919 ADDRSEL_UNLOCK();
920
921 return (match);
922 }
923
924 /*
925 * Subroutines to manage the address selection policy table via sysctl.
926 */
927 struct walkarg {
928 struct sysctl_req *w_req;
929 };
930
931 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
932 SYSCTL_DECL(_net_inet6_ip6);
933 static SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
934 CTLFLAG_RD | CTLFLAG_MPSAFE, in6_src_sysctl,
935 "");
936
937 static int
in6_src_sysctl(SYSCTL_HANDLER_ARGS)938 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
939 {
940 struct walkarg w;
941
942 if (req->newptr)
943 return EPERM;
944
945 bzero(&w, sizeof(w));
946 w.w_req = req;
947
948 return (walk_addrsel_policy(dump_addrsel_policyent, &w));
949 }
950
951 int
in6_src_ioctl(u_long cmd,caddr_t data)952 in6_src_ioctl(u_long cmd, caddr_t data)
953 {
954 struct in6_addrpolicy ent0;
955
956 if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
957 return (EOPNOTSUPP); /* check for safety */
958
959 ent0 = *(struct in6_addrpolicy *)data;
960
961 if (ent0.label == ADDR_LABEL_NOTAPP)
962 return (EINVAL);
963 /* check if the prefix mask is consecutive. */
964 if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
965 return (EINVAL);
966 /* clear trailing garbages (if any) of the prefix address. */
967 IN6_MASK_ADDR(&ent0.addr.sin6_addr, &ent0.addrmask.sin6_addr);
968 ent0.use = 0;
969
970 switch (cmd) {
971 case SIOCAADDRCTL_POLICY:
972 return (add_addrsel_policyent(&ent0));
973 case SIOCDADDRCTL_POLICY:
974 return (delete_addrsel_policyent(&ent0));
975 }
976
977 return (0); /* XXX: compromise compilers */
978 }
979
980 /*
981 * The followings are implementation of the policy table using a
982 * simple tail queue.
983 * XXX such details should be hidden.
984 * XXX implementation using binary tree should be more efficient.
985 */
986 struct addrsel_policyent {
987 TAILQ_ENTRY(addrsel_policyent) ape_entry;
988 struct in6_addrpolicy ape_policy;
989 };
990
991 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
992
993 VNET_DEFINE_STATIC(struct addrsel_policyhead, addrsel_policytab);
994 #define V_addrsel_policytab VNET(addrsel_policytab)
995
996 static void
init_policy_queue(void)997 init_policy_queue(void)
998 {
999
1000 TAILQ_INIT(&V_addrsel_policytab);
1001 }
1002
1003 static int
add_addrsel_policyent(struct in6_addrpolicy * newpolicy)1004 add_addrsel_policyent(struct in6_addrpolicy *newpolicy)
1005 {
1006 struct addrsel_policyent *new, *pol;
1007
1008 new = malloc(sizeof(*new), M_IFADDR,
1009 M_WAITOK);
1010 ADDRSEL_XLOCK();
1011 ADDRSEL_LOCK();
1012
1013 /* duplication check */
1014 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1015 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr,
1016 &pol->ape_policy.addr.sin6_addr) &&
1017 IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr,
1018 &pol->ape_policy.addrmask.sin6_addr)) {
1019 ADDRSEL_UNLOCK();
1020 ADDRSEL_XUNLOCK();
1021 free(new, M_IFADDR);
1022 return (EEXIST); /* or override it? */
1023 }
1024 }
1025
1026 bzero(new, sizeof(*new));
1027
1028 /* XXX: should validate entry */
1029 new->ape_policy = *newpolicy;
1030
1031 TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry);
1032 ADDRSEL_UNLOCK();
1033 ADDRSEL_XUNLOCK();
1034
1035 return (0);
1036 }
1037
1038 static int
delete_addrsel_policyent(struct in6_addrpolicy * key)1039 delete_addrsel_policyent(struct in6_addrpolicy *key)
1040 {
1041 struct addrsel_policyent *pol;
1042
1043 ADDRSEL_XLOCK();
1044 ADDRSEL_LOCK();
1045
1046 /* search for the entry in the table */
1047 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1048 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr,
1049 &pol->ape_policy.addr.sin6_addr) &&
1050 IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr,
1051 &pol->ape_policy.addrmask.sin6_addr)) {
1052 break;
1053 }
1054 }
1055 if (pol == NULL) {
1056 ADDRSEL_UNLOCK();
1057 ADDRSEL_XUNLOCK();
1058 return (ESRCH);
1059 }
1060
1061 TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry);
1062 ADDRSEL_UNLOCK();
1063 ADDRSEL_XUNLOCK();
1064 free(pol, M_IFADDR);
1065
1066 return (0);
1067 }
1068
1069 static int
walk_addrsel_policy(int (* callback)(struct in6_addrpolicy *,void *),void * w)1070 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *), void *w)
1071 {
1072 struct addrsel_policyent *pol;
1073 int error = 0;
1074
1075 ADDRSEL_SLOCK();
1076 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1077 if ((error = (*callback)(&pol->ape_policy, w)) != 0) {
1078 ADDRSEL_SUNLOCK();
1079 return (error);
1080 }
1081 }
1082 ADDRSEL_SUNLOCK();
1083 return (error);
1084 }
1085
1086 static int
dump_addrsel_policyent(struct in6_addrpolicy * pol,void * arg)1087 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg)
1088 {
1089 int error = 0;
1090 struct walkarg *w = arg;
1091
1092 error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
1093
1094 return (error);
1095 }
1096
1097 static struct in6_addrpolicy *
match_addrsel_policy(struct sockaddr_in6 * key)1098 match_addrsel_policy(struct sockaddr_in6 *key)
1099 {
1100 struct addrsel_policyent *pent;
1101 struct in6_addrpolicy *bestpol = NULL, *pol;
1102 int matchlen, bestmatchlen = -1;
1103 u_char *mp, *ep, *k, *p, m;
1104
1105 TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) {
1106 matchlen = 0;
1107
1108 pol = &pent->ape_policy;
1109 mp = (u_char *)&pol->addrmask.sin6_addr;
1110 ep = mp + 16; /* XXX: scope field? */
1111 k = (u_char *)&key->sin6_addr;
1112 p = (u_char *)&pol->addr.sin6_addr;
1113 for (; mp < ep && *mp; mp++, k++, p++) {
1114 m = *mp;
1115 if ((*k & m) != *p)
1116 goto next; /* not match */
1117 if (m == 0xff) /* short cut for a typical case */
1118 matchlen += 8;
1119 else {
1120 while (m >= 0x80) {
1121 matchlen++;
1122 m <<= 1;
1123 }
1124 }
1125 }
1126
1127 /* matched. check if this is better than the current best. */
1128 if (bestpol == NULL ||
1129 matchlen > bestmatchlen) {
1130 bestpol = pol;
1131 bestmatchlen = matchlen;
1132 }
1133
1134 next:
1135 continue;
1136 }
1137
1138 return (bestpol);
1139 }
1140