1 /* $KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (C) 2000 WIDE Project.
7 * Copyright (c) 2010 Hiroki Sato <hrs@FreeBSD.org>
8 * Copyright (c) 2013 Ermal Luci <eri@FreeBSD.org>
9 * Copyright (c) 2017-2021 Rubicon Communications, LLC (Netgate)
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the project nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 /*
38 * 6to4 interface, based on RFC3056.
39 *
40 * 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting.
41 * There is no address mapping defined from IPv6 multicast address to IPv4
42 * address. Therefore, we do not have IFF_MULTICAST on the interface.
43 *
44 * Due to the lack of address mapping for link-local addresses, we cannot
45 * throw packets toward link-local addresses (fe80::x). Also, we cannot throw
46 * packets to link-local multicast addresses (ff02::x).
47 *
48 * Here are interesting symptoms due to the lack of link-local address:
49 *
50 * Unicast routing exchange:
51 * - RIPng: Impossible. Uses link-local multicast packet toward ff02::9,
52 * and link-local addresses as nexthop.
53 * - OSPFv6: Impossible. OSPFv6 assumes that there's link-local address
54 * assigned to the link, and makes use of them. Also, HELLO packets use
55 * link-local multicast addresses (ff02::5 and ff02::6).
56 * - BGP4+: Maybe. You can only use global address as nexthop, and global
57 * address as TCP endpoint address.
58 *
59 * Multicast routing protocols:
60 * - PIM: Hello packet cannot be used to discover adjacent PIM routers.
61 * Adjacent PIM routers must be configured manually (is it really spec-wise
62 * correct thing to do?).
63 *
64 * ICMPv6:
65 * - Redirects cannot be used due to the lack of link-local address.
66 *
67 * stf interface does not have, and will not need, a link-local address.
68 * It seems to have no real benefit and does not help the above symptoms much.
69 * Even if we assign link-locals to interface, we cannot really
70 * use link-local unicast/multicast on top of 6to4 cloud (since there's no
71 * encapsulation defined for link-local address), and the above analysis does
72 * not change. RFC3056 does not mandate the assignment of link-local address
73 * either.
74 *
75 * 6to4 interface has security issues. Refer to
76 * http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt
77 * for details. The code tries to filter out some of malicious packets.
78 * Note that there is no way to be 100% secure.
79 */
80
81 #include <sys/param.h>
82 #include <sys/systm.h>
83 #include <sys/socket.h>
84 #include <sys/sockio.h>
85 #include <sys/mbuf.h>
86 #include <sys/endian.h>
87 #include <sys/errno.h>
88 #include <sys/kernel.h>
89 #include <sys/lock.h>
90 #include <sys/module.h>
91 #include <sys/priv.h>
92 #include <sys/proc.h>
93 #include <sys/queue.h>
94 #include <sys/sdt.h>
95 #include <sys/sysctl.h>
96 #include <machine/cpu.h>
97
98 #include <sys/malloc.h>
99
100 #include <net/if.h>
101 #include <net/if_var.h>
102 #include <net/if_private.h>
103 #include <net/if_clone.h>
104 #include <net/route.h>
105 #include <net/route/nhop.h>
106 #include <net/netisr.h>
107 #include <net/if_stf.h>
108 #include <net/if_types.h>
109 #include <net/vnet.h>
110
111 #include <netinet/in.h>
112 #include <netinet/in_fib.h>
113 #include <netinet/in_systm.h>
114 #include <netinet/ip.h>
115 #include <netinet/ip_var.h>
116 #include <netinet/in_var.h>
117
118 #include <netinet/ip6.h>
119 #include <netinet6/in6_fib.h>
120 #include <netinet6/ip6_var.h>
121 #include <netinet6/in6_var.h>
122 #include <netinet/ip_ecn.h>
123
124 #include <netinet/ip_encap.h>
125
126 #include <machine/stdarg.h>
127
128 #include <net/bpf.h>
129
130 #include <security/mac/mac_framework.h>
131
132 SDT_PROVIDER_DEFINE(if_stf);
133 SDT_PROBE_DEFINE3(if_stf, , encapcheck, in, "struct mbuf *", "int", "int");
134 SDT_PROBE_DEFINE0(if_stf, , encapcheck, accept);
135 SDT_PROBE_DEFINE3(if_stf, , getsrcifa6, in, "struct ifnet *",
136 "struct in6_addr *", "struct in6_addr *");
137 SDT_PROBE_DEFINE2(if_stf, , getsrcifa6, found, "struct in6_addr *",
138 "struct in6_addr *");
139 SDT_PROBE_DEFINE0(if_stf, , getsrcifa6, notfound);
140
141 SDT_PROBE_DEFINE4(if_stf, , stf_output, in, "struct ifnet *", "struct mbuf *",
142 "struct sockaddr *", "struct route *");
143 SDT_PROBE_DEFINE2(if_stf, , stf_output, error, "int", "int");
144 SDT_PROBE_DEFINE1(if_stf, , stf_output, out, "int");
145
146 SDT_PROBE_DEFINE3(if_stf, , checkaddr6, in, "struct stf_softc *",
147 "struct in6_addr *", "struct ifnet *");
148 SDT_PROBE_DEFINE2(if_stf, , checkaddr6, out, "int", "int");
149
150 SDT_PROBE_DEFINE3(if_stf, , stf_input, in, "struct mbuf *", "int", "int");
151 SDT_PROBE_DEFINE2(if_stf, , stf_input, out, "int", "int");
152
153 SDT_PROBE_DEFINE3(if_stf, , ioctl, sv4net, "struct in_addr *",
154 "struct in_addr *", "int");
155 SDT_PROBE_DEFINE1(if_stf, , ioctl, sdstv4, "struct in_addr *");
156 SDT_PROBE_DEFINE1(if_stf, , ioctl, ifaddr, "struct ifaddr *");
157
158 SDT_PROBE_DEFINE4(if_stf, , getin4addr_in6, out, "struct in6_addr *",
159 "struct in6_addr *", "struct in6_addr *", "struct sockaddr_in *");
160
161 SDT_PROBE_DEFINE2(if_stf, , getin4addr, in, "struct in6_addr *", "struct in6_addr *");
162 SDT_PROBE_DEFINE1(if_stf, , getin4addr, out, "struct sockaddr_in *");
163
164 SYSCTL_DECL(_net_link);
165 static SYSCTL_NODE(_net_link, IFT_STF, stf, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
166 "6to4 Interface");
167
168 static int stf_permit_rfc1918 = 0;
169 SYSCTL_INT(_net_link_stf, OID_AUTO, permit_rfc1918, CTLFLAG_RWTUN,
170 &stf_permit_rfc1918, 0, "Permit the use of private IPv4 addresses");
171
172 #define STFUNIT 0
173
174 #define IN6_IS_ADDR_6TO4(x) (ntohs((x)->s6_addr16[0]) == 0x2002)
175
176 /*
177 * XXX: Return a pointer with 16-bit aligned. Don't cast it to
178 * struct in_addr *; use bcopy() instead.
179 */
180 #define GET_V4(x) (&(x)->s6_addr16[1])
181
182 struct stf_softc {
183 struct ifnet *sc_ifp;
184 in_addr_t braddr; /* Border relay IPv4 address */
185 in_addr_t srcv4_addr; /* Our IPv4 WAN address */
186 u_int v4prefixlen; /* How much of the v4 address to include in our address. */
187 u_int sc_fibnum;
188 const struct encaptab *encap_cookie;
189 };
190 #define STF2IFP(sc) ((sc)->sc_ifp)
191
192 static const char stfname[] = "stf";
193
194 static MALLOC_DEFINE(M_STF, stfname, "6to4 Tunnel Interface");
195 static const int ip_stf_ttl = 40;
196
197 static int in_stf_input(struct mbuf *, int, int, void *);
198 static char *stfnames[] = {"stf0", "stf", "6to4", NULL};
199
200 static int stfmodevent(module_t, int, void *);
201 static int stf_encapcheck(const struct mbuf *, int, int, void *);
202 static int stf_getsrcifa6(struct ifnet *, struct in6_addr *, struct in6_addr *);
203 static int stf_output(struct ifnet *, struct mbuf *, const struct sockaddr *,
204 struct route *);
205 static int isrfc1918addr(struct in_addr *);
206 static int stf_checkaddr4(struct stf_softc *, struct in_addr *,
207 struct ifnet *);
208 static int stf_checkaddr6(struct stf_softc *, struct in6_addr *,
209 struct ifnet *);
210 static struct sockaddr_in *stf_getin4addr_in6(struct stf_softc *,
211 struct sockaddr_in *, struct in6_addr, struct in6_addr,
212 struct in6_addr);
213 static struct sockaddr_in *stf_getin4addr(struct stf_softc *,
214 struct sockaddr_in *, struct in6_addr, struct in6_addr);
215 static int stf_ioctl(struct ifnet *, u_long, caddr_t);
216
217 VNET_DEFINE_STATIC(struct if_clone *, stf_cloner);
218 #define V_stf_cloner VNET(stf_cloner)
219
220 static const struct encap_config ipv4_encap_cfg = {
221 .proto = IPPROTO_IPV6,
222 .min_length = sizeof(struct ip),
223 .exact_match = (sizeof(in_addr_t) << 3) + 8,
224 .check = stf_encapcheck,
225 .input = in_stf_input
226 };
227
228 static int
stf_clone_match(struct if_clone * ifc,const char * name)229 stf_clone_match(struct if_clone *ifc, const char *name)
230 {
231 int i;
232
233 for(i = 0; stfnames[i] != NULL; i++) {
234 if (strcmp(stfnames[i], name) == 0)
235 return (1);
236 }
237
238 return (0);
239 }
240
241 static int
stf_clone_create(struct if_clone * ifc,char * name,size_t len,struct ifc_data * ifd,struct ifnet ** ifpp)242 stf_clone_create(struct if_clone *ifc, char *name, size_t len,
243 struct ifc_data *ifd, struct ifnet **ifpp)
244 {
245 char *dp;
246 int err, unit, wildcard;
247 struct stf_softc *sc;
248 struct ifnet *ifp;
249
250 err = ifc_name2unit(name, &unit);
251 if (err != 0)
252 return (err);
253 wildcard = (unit < 0);
254
255 /*
256 * We can only have one unit, but since unit allocation is
257 * already locked, we use it to keep from allocating extra
258 * interfaces.
259 */
260 unit = STFUNIT;
261 err = ifc_alloc_unit(ifc, &unit);
262 if (err != 0)
263 return (err);
264
265 sc = malloc(sizeof(struct stf_softc), M_STF, M_WAITOK | M_ZERO);
266 ifp = STF2IFP(sc) = if_alloc(IFT_STF);
267 ifp->if_softc = sc;
268 sc->sc_fibnum = curthread->td_proc->p_fibnum;
269
270 /*
271 * Set the name manually rather then using if_initname because
272 * we don't conform to the default naming convention for interfaces.
273 * In the wildcard case, we need to update the name.
274 */
275 if (wildcard) {
276 for (dp = name; *dp != '\0'; dp++);
277 if (snprintf(dp, len - (dp-name), "%d", unit) >
278 len - (dp-name) - 1) {
279 /*
280 * This can only be a programmer error and
281 * there's no straightforward way to recover if
282 * it happens.
283 */
284 panic("if_clone_create(): interface name too long");
285 }
286 }
287 strlcpy(ifp->if_xname, name, IFNAMSIZ);
288 ifp->if_dname = stfname;
289 ifp->if_dunit = IF_DUNIT_NONE;
290
291 sc->encap_cookie = ip_encap_attach(&ipv4_encap_cfg, sc, M_WAITOK);
292
293 ifp->if_mtu = IPV6_MMTU;
294 ifp->if_ioctl = stf_ioctl;
295 ifp->if_output = stf_output;
296 ifp->if_snd.ifq_maxlen = ifqmaxlen;
297 if_attach(ifp);
298 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
299 *ifpp = ifp;
300
301 return (0);
302 }
303
304 static int
stf_clone_destroy(struct if_clone * ifc,struct ifnet * ifp,uint32_t flags)305 stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
306 {
307 struct stf_softc *sc = ifp->if_softc;
308 int err __unused;
309
310 err = ip_encap_detach(sc->encap_cookie);
311 KASSERT(err == 0, ("Unexpected error detaching encap_cookie"));
312 bpfdetach(ifp);
313 if_detach(ifp);
314 if_free(ifp);
315
316 free(sc, M_STF);
317 ifc_free_unit(ifc, STFUNIT);
318
319 return (0);
320 }
321
322 static void
vnet_stf_init(const void * unused __unused)323 vnet_stf_init(const void *unused __unused)
324 {
325 struct if_clone_addreq req = {
326 .match_f = stf_clone_match,
327 .create_f = stf_clone_create,
328 .destroy_f = stf_clone_destroy,
329 };
330 V_stf_cloner = ifc_attach_cloner(stfname, &req);
331 }
332 VNET_SYSINIT(vnet_stf_init, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_init, NULL);
333
334 static void
vnet_stf_uninit(const void * unused __unused)335 vnet_stf_uninit(const void *unused __unused)
336 {
337 if_clone_detach(V_stf_cloner);
338 V_stf_cloner = NULL;
339 }
340 VNET_SYSUNINIT(vnet_stf_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_uninit,
341 NULL);
342
343 static int
stfmodevent(module_t mod,int type,void * data)344 stfmodevent(module_t mod, int type, void *data)
345 {
346
347 switch (type) {
348 case MOD_LOAD:
349 /* Done in vnet_stf_init() */
350 break;
351 case MOD_UNLOAD:
352 /* Done in vnet_stf_uninit() */
353 break;
354 default:
355 return (EOPNOTSUPP);
356 }
357
358 return (0);
359 }
360
361 static moduledata_t stf_mod = {
362 "if_stf",
363 stfmodevent,
364 0
365 };
366
367 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
368 MODULE_VERSION(if_stf, 2);
369
370 static int
stf_encapcheck(const struct mbuf * m,int off,int proto,void * arg)371 stf_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
372 {
373 struct ip ip;
374 struct stf_softc *sc;
375 struct in6_addr addr6, mask6;
376 struct sockaddr_in sin4addr, sin4mask;
377
378 SDT_PROBE3(if_stf, , encapcheck, in, m, off, proto);
379
380 sc = (struct stf_softc *)arg;
381 if (sc == NULL)
382 return (0);
383
384 if ((STF2IFP(sc)->if_flags & IFF_UP) == 0)
385 return (0);
386
387 /* IFF_LINK0 means "no decapsulation" */
388 if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0)
389 return (0);
390
391 if (proto != IPPROTO_IPV6)
392 return (0);
393
394 m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
395
396 if (ip.ip_v != 4)
397 return (0);
398
399 if (stf_getsrcifa6(STF2IFP(sc), &addr6, &mask6) != 0)
400 return (0);
401
402 if (sc->srcv4_addr != INADDR_ANY) {
403 sin4addr.sin_addr.s_addr = sc->srcv4_addr;
404 sin4addr.sin_family = AF_INET;
405 } else
406 if (stf_getin4addr(sc, &sin4addr, addr6, mask6) == NULL)
407 return (0);
408
409 if (sin4addr.sin_addr.s_addr != ip.ip_dst.s_addr)
410 return (0);
411
412 if (IN6_IS_ADDR_6TO4(&addr6)) {
413 /*
414 * 6to4 (RFC 3056).
415 * Check if IPv4 src matches the IPv4 address derived
416 * from the local 6to4 address masked by prefixmask.
417 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
418 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
419 */
420 memcpy(&sin4mask.sin_addr, GET_V4(&mask6),
421 sizeof(sin4mask.sin_addr));
422 if ((sin4addr.sin_addr.s_addr & sin4mask.sin_addr.s_addr) !=
423 (ip.ip_src.s_addr & sin4mask.sin_addr.s_addr))
424 return (0);
425 } else {
426 /* 6rd (RFC 5569) */
427 /*
428 * No restriction on the src address in the case of
429 * 6rd because the stf(4) interface always has a
430 * prefix which covers whole of IPv4 src address
431 * range. So, stf_output() will catch all of
432 * 6rd-capsuled IPv4 traffic with suspicious inner dst
433 * IPv4 address (i.e. the IPv6 destination address is
434 * one the admin does not like to route to outside),
435 * and then it discard them silently.
436 */
437 }
438
439 SDT_PROBE0(if_stf, , encapcheck, accept);
440
441 /* stf interface makes single side match only */
442 return (32);
443 }
444
445 static int
stf_getsrcifa6(struct ifnet * ifp,struct in6_addr * addr,struct in6_addr * mask)446 stf_getsrcifa6(struct ifnet *ifp, struct in6_addr *addr, struct in6_addr *mask)
447 {
448 struct ifaddr *ia;
449 struct in_ifaddr *ia4;
450 struct in6_addr addr6, mask6;
451 struct sockaddr_in sin4;
452 struct stf_softc *sc;
453 struct in_addr in;
454
455 NET_EPOCH_ASSERT();
456
457 sc = ifp->if_softc;
458
459 SDT_PROBE3(if_stf, , getsrcifa6, in, ifp, addr, mask);
460
461 CK_STAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
462 if (ia->ifa_addr->sa_family != AF_INET6)
463 continue;
464
465 addr6 = *IFA_IN6(ia);
466 mask6 = *IFA_MASKIN6(ia);
467 if (sc->srcv4_addr != INADDR_ANY)
468 bcopy(&sc->srcv4_addr, &in, sizeof(in));
469 else {
470 if (stf_getin4addr(sc, &sin4, addr6, mask6) == NULL)
471 continue;
472 bcopy(&sin4.sin_addr, &in, sizeof(in));
473 }
474
475 CK_LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash)
476 if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
477 break;
478 if (ia4 == NULL)
479 continue;
480
481 *addr = addr6;
482 *mask = mask6;
483
484 SDT_PROBE2(if_stf, , getsrcifa6, found, addr, mask);
485
486 return (0);
487 }
488
489 SDT_PROBE0(if_stf, , getsrcifa6, notfound);
490
491 return (ENOENT);
492 }
493
494 static int
stf_output(struct ifnet * ifp,struct mbuf * m,const struct sockaddr * dst,struct route * ro)495 stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
496 struct route *ro)
497 {
498 struct stf_softc *sc;
499 const struct sockaddr_in6 *dst6;
500 struct sockaddr_in dst4, src4;
501 u_int8_t tos;
502 struct ip *ip;
503 struct ip6_hdr *ip6;
504 struct in6_addr addr6, mask6;
505 int error;
506
507 SDT_PROBE4(if_stf, , stf_output, in, ifp, m, dst, ro);
508
509 #ifdef MAC
510 error = mac_ifnet_check_transmit(ifp, m);
511 if (error) {
512 m_freem(m);
513 SDT_PROBE2(if_stf, , stf_output, error, error, __LINE__);
514 return (error);
515 }
516 #endif
517
518 sc = ifp->if_softc;
519 dst6 = (const struct sockaddr_in6 *)dst;
520
521 /* just in case */
522 if ((ifp->if_flags & IFF_UP) == 0) {
523 m_freem(m);
524 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
525 SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__);
526 return (ENETDOWN);
527 }
528
529 /*
530 * If we don't have an ip4 address that match my inner ip6 address,
531 * we shouldn't generate output. Without this check, we'll end up
532 * using wrong IPv4 source.
533 */
534 if (stf_getsrcifa6(ifp, &addr6, &mask6) != 0) {
535 m_freem(m);
536 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
537 SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__);
538 return (ENETDOWN);
539 }
540
541 if (m->m_len < sizeof(*ip6)) {
542 m = m_pullup(m, sizeof(*ip6));
543 if (!m) {
544 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
545 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS,
546 __LINE__);
547 return (ENOBUFS);
548 }
549 }
550 ip6 = mtod(m, struct ip6_hdr *);
551 tos = IPV6_TRAFFIC_CLASS(ip6);
552
553 /*
554 * Pickup the right outer dst addr from the list of candidates.
555 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
556 */
557 if (stf_getin4addr_in6(sc, &dst4, addr6, mask6,
558 ip6->ip6_dst) == NULL) {
559 if (sc->braddr != INADDR_ANY)
560 dst4.sin_addr.s_addr = sc->braddr;
561 else if (stf_getin4addr_in6(sc, &dst4, addr6, mask6,
562 dst6->sin6_addr) == NULL) {
563 m_freem(m);
564 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
565 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH,
566 __LINE__);
567 return (ENETUNREACH);
568 }
569 }
570
571 if (bpf_peers_present(ifp->if_bpf)) {
572 /*
573 * We need to prepend the address family as
574 * a four byte field. Cons up a dummy header
575 * to pacify bpf. This is safe because bpf
576 * will only read from the mbuf (i.e., it won't
577 * try to free it or keep a pointer a to it).
578 */
579 u_int af = AF_INET6;
580 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
581 }
582
583 M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
584 if (m == NULL) {
585 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
586 SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, __LINE__);
587 return (ENOBUFS);
588 }
589 ip = mtod(m, struct ip *);
590
591 bzero(ip, sizeof(*ip));
592
593 if (sc->srcv4_addr != INADDR_ANY)
594 src4.sin_addr.s_addr = sc->srcv4_addr;
595 else if (stf_getin4addr(sc, &src4, addr6, mask6) == NULL) {
596 m_freem(m);
597 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
598 SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, __LINE__);
599 return (ENETUNREACH);
600 }
601 bcopy(&src4.sin_addr, &ip->ip_src, sizeof(ip->ip_src));
602 bcopy(&dst4.sin_addr, &ip->ip_dst, sizeof(ip->ip_dst));
603
604 ip->ip_p = IPPROTO_IPV6;
605 ip->ip_ttl = ip_stf_ttl;
606 ip->ip_len = htons(m->m_pkthdr.len);
607 if (ifp->if_flags & IFF_LINK1)
608 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
609 else
610 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
611
612 M_SETFIB(m, sc->sc_fibnum);
613 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
614 error = ip_output(m, NULL, NULL, 0, NULL, NULL);
615
616 SDT_PROBE1(if_stf, , stf_output, out, error);
617 return (error);
618 }
619
620 static int
isrfc1918addr(struct in_addr * in)621 isrfc1918addr(struct in_addr *in)
622 {
623 /*
624 * returns 1 if private address range:
625 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
626 */
627 if (stf_permit_rfc1918 == 0 && (
628 (ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
629 (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
630 (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168))
631 return (1);
632
633 return (0);
634 }
635
636 static int
stf_checkaddr4(struct stf_softc * sc,struct in_addr * in,struct ifnet * inifp)637 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in, struct ifnet *inifp)
638 {
639 struct in_ifaddr *ia4;
640
641 /*
642 * reject packets with the following address:
643 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
644 */
645 if (IN_MULTICAST(ntohl(in->s_addr)))
646 return (-1);
647 switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
648 case 0: case 127: case 255:
649 return (-1);
650 }
651
652 /*
653 * reject packets with broadcast
654 */
655 CK_STAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) {
656 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
657 continue;
658 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
659 return (-1);
660 }
661 }
662
663 /*
664 * perform ingress filter
665 */
666 if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) {
667 struct nhop_object *nh;
668
669 NET_EPOCH_ASSERT();
670 nh = fib4_lookup(sc->sc_fibnum, *in, 0, 0, 0);
671 if (nh == NULL)
672 return (-1);
673
674 if (nh->nh_ifp != inifp)
675 return (-1);
676 }
677
678 return (0);
679 }
680
681 static int
stf_checkaddr6(struct stf_softc * sc,struct in6_addr * in6,struct ifnet * inifp)682 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6, struct ifnet *inifp)
683 {
684 SDT_PROBE3(if_stf, , checkaddr6, in, sc, in6, inifp);
685
686 /*
687 * check 6to4 addresses
688 */
689 if (IN6_IS_ADDR_6TO4(in6)) {
690 struct in_addr in4;
691 int ret;
692
693 bcopy(GET_V4(in6), &in4, sizeof(in4));
694 ret = stf_checkaddr4(sc, &in4, inifp);
695 SDT_PROBE2(if_stf, , checkaddr6, out, ret, __LINE__);
696 return (ret);
697 }
698
699 /*
700 * reject anything that look suspicious. the test is implemented
701 * in ip6_input too, but we check here as well to
702 * (1) reject bad packets earlier, and
703 * (2) to be safe against future ip6_input change.
704 */
705 if (IN6_IS_ADDR_V4COMPAT(in6)) {
706 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__);
707 return (-1);
708 }
709
710 if (IN6_IS_ADDR_V4MAPPED(in6)) {
711 SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__);
712 return (-1);
713 }
714
715 SDT_PROBE2(if_stf, , checkaddr6, out, 0, __LINE__);
716 return (0);
717 }
718
719 static int
in_stf_input(struct mbuf * m,int off,int proto,void * arg)720 in_stf_input(struct mbuf *m, int off, int proto, void *arg)
721 {
722 struct stf_softc *sc = arg;
723 struct ip ip;
724 struct ip6_hdr *ip6;
725 u_int8_t otos, itos;
726 struct ifnet *ifp;
727 struct nhop_object *nh;
728
729 NET_EPOCH_ASSERT();
730
731 SDT_PROBE3(if_stf, , stf_input, in, m, off, proto);
732
733 if (proto != IPPROTO_IPV6) {
734 m_freem(m);
735 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
736 return (IPPROTO_DONE);
737 }
738
739 m_copydata(m, 0, sizeof(struct ip), (caddr_t)&ip);
740 if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) {
741 m_freem(m);
742 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
743 return (IPPROTO_DONE);
744 }
745
746 ifp = STF2IFP(sc);
747
748 #ifdef MAC
749 mac_ifnet_create_mbuf(ifp, m);
750 #endif
751
752 /*
753 * perform sanity check against outer src/dst.
754 * for source, perform ingress filter as well.
755 */
756 if (stf_checkaddr4(sc, &ip.ip_dst, NULL) < 0 ||
757 stf_checkaddr4(sc, &ip.ip_src, m->m_pkthdr.rcvif) < 0) {
758 m_freem(m);
759 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
760 return (IPPROTO_DONE);
761 }
762
763 otos = ip.ip_tos;
764 m_adj(m, off);
765
766 if (m->m_len < sizeof(*ip6)) {
767 m = m_pullup(m, sizeof(*ip6));
768 if (!m) {
769 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE,
770 __LINE__);
771 return (IPPROTO_DONE);
772 }
773 }
774 ip6 = mtod(m, struct ip6_hdr *);
775
776 /*
777 * perform sanity check against inner src/dst.
778 * for source, perform ingress filter as well.
779 */
780 if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
781 stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
782 m_freem(m);
783 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
784 return (IPPROTO_DONE);
785 }
786
787 /*
788 * reject packets with private address range.
789 * (requirement from RFC3056 section 2 1st paragraph)
790 */
791 if ((IN6_IS_ADDR_6TO4(&ip6->ip6_src) && isrfc1918addr(&ip.ip_src)) ||
792 (IN6_IS_ADDR_6TO4(&ip6->ip6_dst) && isrfc1918addr(&ip.ip_dst))) {
793 m_freem(m);
794 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
795 return (IPPROTO_DONE);
796 }
797
798 /*
799 * Ignore if the destination is the same stf interface because
800 * all of valid IPv6 outgoing traffic should go interfaces
801 * except for it.
802 */
803 nh = fib6_lookup(sc->sc_fibnum, &ip6->ip6_dst, 0, 0, 0);
804 if (nh == NULL) {
805 m_free(m);
806 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
807 return (IPPROTO_DONE);
808 }
809 if ((nh->nh_ifp == ifp) &&
810 (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &nh->gw6_sa.sin6_addr))) {
811 m_free(m);
812 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
813 return (IPPROTO_DONE);
814 }
815
816 itos = IPV6_TRAFFIC_CLASS(ip6);
817 if ((ifp->if_flags & IFF_LINK1) != 0)
818 ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
819 else
820 ip_ecn_egress(ECN_NOCARE, &otos, &itos);
821 ip6->ip6_flow &= ~htonl(0xff << 20);
822 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
823
824 m->m_pkthdr.rcvif = ifp;
825
826 if (bpf_peers_present(ifp->if_bpf)) {
827 /*
828 * We need to prepend the address family as
829 * a four byte field. Cons up a dummy header
830 * to pacify bpf. This is safe because bpf
831 * will only read from the mbuf (i.e., it won't
832 * try to free it or keep a pointer a to it).
833 */
834 u_int32_t af = AF_INET6;
835 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
836 }
837
838 /*
839 * Put the packet to the network layer input queue according to the
840 * specified address family.
841 * See net/if_gif.c for possible issues with packet processing
842 * reorder due to extra queueing.
843 */
844 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
845 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
846 M_SETFIB(m, ifp->if_fib);
847 netisr_dispatch(NETISR_IPV6, m);
848 SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
849 return (IPPROTO_DONE);
850 }
851
852 static struct sockaddr_in *
stf_getin4addr_in6(struct stf_softc * sc,struct sockaddr_in * sin,struct in6_addr addr6,struct in6_addr mask6,struct in6_addr in6)853 stf_getin4addr_in6(struct stf_softc *sc, struct sockaddr_in *sin,
854 struct in6_addr addr6, struct in6_addr mask6, struct in6_addr in6)
855 {
856 int i;
857 struct sockaddr_in *out;
858
859 /*
860 * When (src addr & src mask) != (in6 & src mask),
861 * the dst is not in the 6rd domain. The IPv4 address must
862 * not be used.
863 */
864 for (i = 0; i < sizeof(addr6); i++) {
865 if ((((u_char *)&addr6)[i] & ((u_char *)&mask6)[i]) !=
866 (((u_char *)&in6)[i] & ((u_char *)&mask6)[i])) {
867 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6,
868 &mask6, &in6, NULL);
869 return (NULL);
870 }
871 }
872
873 /* After the mask check, use in6 instead of addr6. */
874 out = stf_getin4addr(sc, sin, in6, mask6);
875 SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, &mask6, &in6, out);
876 return (out);
877 }
878
879 static struct sockaddr_in *
stf_getin4addr(struct stf_softc * sc,struct sockaddr_in * sin,struct in6_addr addr6,struct in6_addr mask6)880 stf_getin4addr(struct stf_softc *sc, struct sockaddr_in *sin,
881 struct in6_addr addr6, struct in6_addr mask6)
882 {
883 struct in_addr *in;
884
885 SDT_PROBE2(if_stf, , getin4addr, in, &addr6, &mask6);
886
887 memset(sin, 0, sizeof(*sin));
888 in = &sin->sin_addr;
889 if (IN6_IS_ADDR_6TO4(&addr6)) {
890 /* 6to4 (RFC 3056) */
891 bcopy(GET_V4(&addr6), in, sizeof(*in));
892 if (isrfc1918addr(in))
893 return (NULL);
894 } else {
895 /* 6rd (RFC 5569) */
896 in_addr_t v4prefix;
897 uint8_t *v6 = (uint8_t*)&addr6;
898 uint64_t v6prefix;
899 u_int plen;
900 u_int v4suffixlen;
901
902 v4prefix = 0;
903 if (sc->v4prefixlen < 32) {
904 v4suffixlen = 32 - sc->v4prefixlen;
905 v4prefix = ntohl(sc->srcv4_addr) &
906 (0xffffffffU << v4suffixlen);
907 } else {
908 MPASS(sc->v4prefixlen == 32);
909 v4suffixlen = 32;
910 }
911
912 plen = in6_mask2len(&mask6, NULL);
913 if (plen > 64)
914 return (NULL);
915
916 /* To make this simple we do not support prefixes longer than
917 * 64 bits. RFC5969 says "a 6rd delegated prefix SHOULD be /64
918 * or shorter." so this is a moderately safe assumption. */
919 v6prefix = be64toh(*(uint64_t *)v6);
920
921 /* Shift away the v6 prefix itself. */
922 v6prefix <<= plen;
923 v6prefix >>= plen;
924
925 /* Now shift away everything after the v4 address. */
926 v6prefix >>= 64 - plen - v4suffixlen;
927
928 sin->sin_addr.s_addr = htonl(v4prefix | (uint32_t)v6prefix);
929 }
930
931 SDT_PROBE1(if_stf, , getin4addr, out, sin);
932
933 return (sin);
934 }
935
936 static int
stf_ioctl(struct ifnet * ifp,u_long cmd,caddr_t data)937 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
938 {
939 struct ifaddr *ifa;
940 struct ifdrv *ifd;
941 struct ifreq *ifr;
942 struct sockaddr_in sin4;
943 struct stf_softc *sc_cur;
944 struct stfv4args args;
945 int error, mtu;
946
947 error = 0;
948 sc_cur = ifp->if_softc;
949
950 switch (cmd) {
951 case SIOCSDRVSPEC:
952 ifd = (struct ifdrv *)data;
953 error = priv_check(curthread, PRIV_NET_ADDIFADDR);
954 if (error)
955 break;
956 if (ifd->ifd_cmd == STF6RD_SV4NET) {
957 if (ifd->ifd_len != sizeof(args)) {
958 error = EINVAL;
959 break;
960 }
961 bzero(&args, sizeof(args));
962 error = copyin(ifd->ifd_data, &args, ifd->ifd_len);
963 if (error)
964 break;
965
966 if (args.v4_prefixlen < 1 || args.v4_prefixlen > 32) {
967 error = EINVAL;
968 break;
969 }
970
971 bcopy(&args.srcv4_addr, &sc_cur->srcv4_addr,
972 sizeof(sc_cur->srcv4_addr));
973 sc_cur->v4prefixlen = args.v4_prefixlen;
974 SDT_PROBE3(if_stf, , ioctl, sv4net, sc_cur->srcv4_addr,
975 sc_cur->srcv4_addr, sc_cur->v4prefixlen);
976 } else if (ifd->ifd_cmd == STF6RD_SBR) {
977 if (ifd->ifd_len != sizeof(args)) {
978 error = EINVAL;
979 break;
980 }
981 bzero(&args, sizeof(args));
982 error = copyin(ifd->ifd_data, &args, ifd->ifd_len);
983 if (error)
984 break;
985 sc_cur->braddr = args.braddr.s_addr;
986 SDT_PROBE1(if_stf, , ioctl, sdstv4,
987 sc_cur->braddr);
988 } else
989 error = EINVAL;
990 break;
991 case SIOCGDRVSPEC:
992 ifd = (struct ifdrv *)data;
993 if (ifd->ifd_cmd != STF6RD_GV4NET) {
994 error = EINVAL;
995 break;
996 }
997 if (ifd->ifd_len != sizeof(args)) {
998 error = EINVAL;
999 break;
1000 }
1001 bzero(&args, sizeof(args));
1002 args.srcv4_addr.s_addr = sc_cur->srcv4_addr;
1003 args.braddr.s_addr = sc_cur->braddr;
1004 args.v4_prefixlen = sc_cur->v4prefixlen;
1005 error = copyout(&args, ifd->ifd_data, ifd->ifd_len);
1006 break;
1007 case SIOCSIFADDR:
1008 ifa = (struct ifaddr *)data;
1009 SDT_PROBE1(if_stf, , ioctl, ifaddr, ifa);
1010 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
1011 error = EAFNOSUPPORT;
1012 break;
1013 }
1014 if (stf_getin4addr(sc_cur, &sin4,
1015 satosin6(ifa->ifa_addr)->sin6_addr,
1016 satosin6(ifa->ifa_netmask)->sin6_addr) == NULL) {
1017 error = EINVAL;
1018 break;
1019 }
1020 ifp->if_flags |= IFF_UP;
1021 ifp->if_drv_flags |= IFF_DRV_RUNNING;
1022 break;
1023
1024 case SIOCADDMULTI:
1025 case SIOCDELMULTI:
1026 ifr = (struct ifreq *)data;
1027 if (ifr && ifr->ifr_addr.sa_family == AF_INET6)
1028 ;
1029 else
1030 error = EAFNOSUPPORT;
1031 break;
1032
1033 case SIOCGIFMTU:
1034 break;
1035
1036 case SIOCSIFMTU:
1037 ifr = (struct ifreq *)data;
1038 mtu = ifr->ifr_mtu;
1039 /* RFC 4213 3.2 ideal world MTU */
1040 if (mtu < IPV6_MINMTU || mtu > IF_MAXMTU - 20)
1041 return (EINVAL);
1042 ifp->if_mtu = mtu;
1043 break;
1044
1045 default:
1046 error = EINVAL;
1047 break;
1048 }
1049
1050 return (error);
1051 }
1052