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