1 /*-
2 * Copyright (c) 2014, 2018 Andrey V. Elsukov <ae@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29
30 #include "opt_inet.h"
31 #include "opt_inet6.h"
32
33 #include <sys/param.h>
34 #include <sys/jail.h>
35 #include <sys/systm.h>
36 #include <sys/socket.h>
37 #include <sys/socketvar.h>
38 #include <sys/sockio.h>
39 #include <sys/mbuf.h>
40 #include <sys/errno.h>
41 #include <sys/kernel.h>
42 #include <sys/sysctl.h>
43 #include <sys/malloc.h>
44 #include <sys/proc.h>
45
46 #include <net/if.h>
47 #include <net/if_var.h>
48 #include <net/vnet.h>
49
50 #include <netinet/in.h>
51 #ifdef INET
52 #include <net/ethernet.h>
53 #include <netinet/ip.h>
54 #endif
55 #include <netinet/in_pcb.h>
56 #include <netinet/ip_encap.h>
57 #include <netinet/ip_var.h>
58 #include <netinet/ip6.h>
59 #include <netinet/udp.h>
60 #include <netinet/udp_var.h>
61 #include <netinet6/ip6_var.h>
62 #include <netinet6/in6_var.h>
63 #include <netinet6/scope6_var.h>
64 #include <net/if_gre.h>
65
66 VNET_DEFINE(int, ip6_gre_hlim) = IPV6_DEFHLIM;
67 #define V_ip6_gre_hlim VNET(ip6_gre_hlim)
68
69 SYSCTL_DECL(_net_inet6_ip6);
70 SYSCTL_INT(_net_inet6_ip6, OID_AUTO, grehlim, CTLFLAG_VNET | CTLFLAG_RW,
71 &VNET_NAME(ip6_gre_hlim), 0, "Default hop limit for encapsulated packets");
72
73 struct in6_gre_socket {
74 struct gre_socket base;
75 struct in6_addr addr; /* scope zone id is embedded */
76 };
77 VNET_DEFINE_STATIC(struct gre_sockets *, ipv6_sockets) = NULL;
78 VNET_DEFINE_STATIC(struct gre_list *, ipv6_hashtbl) = NULL;
79 VNET_DEFINE_STATIC(struct gre_list *, ipv6_srchashtbl) = NULL;
80 #define V_ipv6_sockets VNET(ipv6_sockets)
81 #define V_ipv6_hashtbl VNET(ipv6_hashtbl)
82 #define V_ipv6_srchashtbl VNET(ipv6_srchashtbl)
83 #define GRE_HASH(src, dst) (V_ipv6_hashtbl[\
84 in6_gre_hashval((src), (dst)) & (GRE_HASH_SIZE - 1)])
85 #define GRE_SRCHASH(src) (V_ipv6_srchashtbl[\
86 fnv_32_buf((src), sizeof(*src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)])
87 #define GRE_SOCKHASH(src) (V_ipv6_sockets[\
88 fnv_32_buf((src), sizeof(*src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)])
89 #define GRE_HASH_SC(sc) GRE_HASH(&(sc)->gre_oip6.ip6_src,\
90 &(sc)->gre_oip6.ip6_dst)
91
92 static uint32_t
93 in6_gre_hashval(const struct in6_addr *src, const struct in6_addr *dst)
94 {
95 uint32_t ret;
96
97 ret = fnv_32_buf(src, sizeof(*src), FNV1_32_INIT);
98 return (fnv_32_buf(dst, sizeof(*dst), ret));
99 }
100
101 static struct gre_socket*
102 in6_gre_lookup_socket(const struct in6_addr *addr)
103 {
104 struct gre_socket *gs;
105 struct in6_gre_socket *s;
106
107 CK_LIST_FOREACH(gs, &GRE_SOCKHASH(addr), chain) {
108 s = __containerof(gs, struct in6_gre_socket, base);
109 if (IN6_ARE_ADDR_EQUAL(&s->addr, addr))
110 break;
111 }
112 return (gs);
113 }
114
115 static int
116 in6_gre_checkdup(const struct gre_softc *sc, const struct in6_addr *src,
117 const struct in6_addr *dst, uint32_t opts)
118 {
119 struct gre_list *head;
120 struct gre_softc *tmp;
121 struct gre_socket *gs;
122
123 if (sc->gre_family == AF_INET6 &&
124 IN6_ARE_ADDR_EQUAL(&sc->gre_oip6.ip6_src, src) &&
125 IN6_ARE_ADDR_EQUAL(&sc->gre_oip6.ip6_dst, dst) &&
126 (sc->gre_options & GRE_UDPENCAP) == (opts & GRE_UDPENCAP))
127 return (EEXIST);
128
129 if (opts & GRE_UDPENCAP) {
130 gs = in6_gre_lookup_socket(src);
131 if (gs == NULL)
132 return (0);
133 head = &gs->list;
134 } else
135 head = &GRE_HASH(src, dst);
136
137 CK_LIST_FOREACH(tmp, head, chain) {
138 if (tmp == sc)
139 continue;
140 if (IN6_ARE_ADDR_EQUAL(&tmp->gre_oip6.ip6_src, src) &&
141 IN6_ARE_ADDR_EQUAL(&tmp->gre_oip6.ip6_dst, dst))
142 return (EADDRNOTAVAIL);
143 }
144 return (0);
145 }
146
147 static int
148 in6_gre_lookup(const struct mbuf *m, int off, int proto, void **arg)
149 {
150 const struct ip6_hdr *ip6;
151 struct gre_softc *sc;
152
153 if (V_ipv6_hashtbl == NULL)
154 return (0);
155
156 MPASS(in_epoch(net_epoch_preempt));
157 ip6 = mtod(m, const struct ip6_hdr *);
158 CK_LIST_FOREACH(sc, &GRE_HASH(&ip6->ip6_dst, &ip6->ip6_src), chain) {
159 /*
160 * This is an inbound packet, its ip6_dst is source address
161 * in softc.
162 */
163 if (IN6_ARE_ADDR_EQUAL(&sc->gre_oip6.ip6_src,
164 &ip6->ip6_dst) &&
165 IN6_ARE_ADDR_EQUAL(&sc->gre_oip6.ip6_dst,
166 &ip6->ip6_src)) {
167 if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0)
168 return (0);
169 *arg = sc;
170 return (ENCAP_DRV_LOOKUP);
171 }
172 }
173 return (0);
174 }
175
176 /*
177 * Check that ingress address belongs to local host.
178 */
179 static void
180 in6_gre_set_running(struct gre_softc *sc)
181 {
182
183 if (in6_localip(&sc->gre_oip6.ip6_src))
184 GRE2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
185 else
186 GRE2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
187 }
188
189 /*
190 * ifaddr_event handler.
191 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
192 * source address spoofing.
193 */
194 static void
195 in6_gre_srcaddr(void *arg __unused, const struct sockaddr *sa,
196 int event __unused)
197 {
198 const struct sockaddr_in6 *sin;
199 struct gre_softc *sc;
200
201 /* Check that VNET is ready */
202 if (V_ipv6_hashtbl == NULL)
203 return;
204
205 MPASS(in_epoch(net_epoch_preempt));
206 sin = (const struct sockaddr_in6 *)sa;
207 CK_LIST_FOREACH(sc, &GRE_SRCHASH(&sin->sin6_addr), srchash) {
208 if (IN6_ARE_ADDR_EQUAL(&sc->gre_oip6.ip6_src,
209 &sin->sin6_addr) == 0)
210 continue;
211 in6_gre_set_running(sc);
212 }
213 }
214
215 static void
216 in6_gre_udp_input(struct mbuf *m, int off, struct inpcb *inp,
217 const struct sockaddr *sa, void *ctx)
218 {
219 struct epoch_tracker et;
220 struct gre_socket *gs;
221 struct gre_softc *sc;
222 struct sockaddr_in6 dst;
223
224 NET_EPOCH_ENTER_ET(et);
225 /*
226 * udp_append() holds reference to inp, it is safe to check
227 * inp_flags2 without INP_RLOCK().
228 * If socket was closed before we have entered NET_EPOCH section,
229 * INP_FREED flag should be set. Otherwise it should be safe to
230 * make access to ctx data, because gre_so will be freed by
231 * gre_sofree() via epoch_call().
232 */
233 if (__predict_false(inp->inp_flags2 & INP_FREED)) {
234 NET_EPOCH_EXIT_ET(et);
235 m_freem(m);
236 return;
237 }
238
239 gs = (struct gre_socket *)ctx;
240 dst = *(const struct sockaddr_in6 *)sa;
241 if (sa6_embedscope(&dst, 0)) {
242 NET_EPOCH_EXIT_ET(et);
243 m_freem(m);
244 return;
245 }
246 CK_LIST_FOREACH(sc, &gs->list, chain) {
247 if (IN6_ARE_ADDR_EQUAL(&sc->gre_oip6.ip6_dst, &dst.sin6_addr))
248 break;
249 }
250 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){
251 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc);
252 NET_EPOCH_EXIT_ET(et);
253 return;
254 }
255 m_freem(m);
256 NET_EPOCH_EXIT_ET(et);
257 }
258
259 static int
260 in6_gre_setup_socket(struct gre_softc *sc)
261 {
262 struct sockopt sopt;
263 struct sockaddr_in6 sin6;
264 struct in6_gre_socket *s;
265 struct gre_socket *gs;
266 int error, value;
267
268 /*
269 * NOTE: we are protected with gre_ioctl_sx lock.
270 *
271 * First check that socket is already configured.
272 * If so, check that source address was not changed.
273 * If address is different, check that there are no other tunnels
274 * and close socket.
275 */
276 gs = sc->gre_so;
277 if (gs != NULL) {
278 s = __containerof(gs, struct in6_gre_socket, base);
279 if (!IN6_ARE_ADDR_EQUAL(&s->addr, &sc->gre_oip6.ip6_src)) {
280 if (CK_LIST_EMPTY(&gs->list)) {
281 CK_LIST_REMOVE(gs, chain);
282 soclose(gs->so);
283 epoch_call(net_epoch_preempt, &gs->epoch_ctx,
284 gre_sofree);
285 }
286 gs = sc->gre_so = NULL;
287 }
288 }
289
290 if (gs == NULL) {
291 /*
292 * Check that socket for given address is already
293 * configured.
294 */
295 gs = in6_gre_lookup_socket(&sc->gre_oip6.ip6_src);
296 if (gs == NULL) {
297 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO);
298 s->addr = sc->gre_oip6.ip6_src;
299 gs = &s->base;
300
301 error = socreate(sc->gre_family, &gs->so,
302 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred,
303 curthread);
304 if (error != 0) {
305 if_printf(GRE2IFP(sc),
306 "cannot create socket: %d\n", error);
307 free(s, M_GRE);
308 return (error);
309 }
310
311 error = udp_set_kernel_tunneling(gs->so,
312 in6_gre_udp_input, NULL, gs);
313 if (error != 0) {
314 if_printf(GRE2IFP(sc),
315 "cannot set UDP tunneling: %d\n", error);
316 goto fail;
317 }
318
319 memset(&sopt, 0, sizeof(sopt));
320 sopt.sopt_dir = SOPT_SET;
321 sopt.sopt_level = IPPROTO_IPV6;
322 sopt.sopt_name = IPV6_BINDANY;
323 sopt.sopt_val = &value;
324 sopt.sopt_valsize = sizeof(value);
325 value = 1;
326 error = sosetopt(gs->so, &sopt);
327 if (error != 0) {
328 if_printf(GRE2IFP(sc),
329 "cannot set IPV6_BINDANY opt: %d\n",
330 error);
331 goto fail;
332 }
333
334 memset(&sin6, 0, sizeof(sin6));
335 sin6.sin6_family = AF_INET6;
336 sin6.sin6_len = sizeof(sin6);
337 sin6.sin6_addr = sc->gre_oip6.ip6_src;
338 sin6.sin6_port = htons(GRE_UDPPORT);
339 error = sa6_recoverscope(&sin6);
340 if (error != 0) {
341 if_printf(GRE2IFP(sc),
342 "cannot determine scope zone id: %d\n",
343 error);
344 goto fail;
345 }
346 error = sobind(gs->so, (struct sockaddr *)&sin6,
347 curthread);
348 if (error != 0) {
349 if_printf(GRE2IFP(sc),
350 "cannot bind socket: %d\n", error);
351 goto fail;
352 }
353 /* Add socket to the chain */
354 CK_LIST_INSERT_HEAD(
355 &GRE_SOCKHASH(&sc->gre_oip6.ip6_src), gs, chain);
356 }
357 }
358
359 /* Add softc to the socket's list */
360 CK_LIST_INSERT_HEAD(&gs->list, sc, chain);
361 sc->gre_so = gs;
362 return (0);
363 fail:
364 soclose(gs->so);
365 free(s, M_GRE);
366 return (error);
367 }
368
369 static int
370 in6_gre_attach(struct gre_softc *sc)
371 {
372 struct grehdr *gh;
373 int error;
374
375 if (sc->gre_options & GRE_UDPENCAP) {
376 sc->gre_csumflags = CSUM_UDP_IPV6;
377 sc->gre_hlen = sizeof(struct greudp6);
378 sc->gre_oip6.ip6_nxt = IPPROTO_UDP;
379 gh = &sc->gre_udp6hdr->gi6_gre;
380 gre_update_udphdr(sc, &sc->gre_udp6,
381 in6_cksum_pseudo(&sc->gre_oip6, 0, 0, 0));
382 } else {
383 sc->gre_hlen = sizeof(struct greip6);
384 sc->gre_oip6.ip6_nxt = IPPROTO_GRE;
385 gh = &sc->gre_ip6hdr->gi6_gre;
386 }
387 sc->gre_oip6.ip6_vfc = IPV6_VERSION;
388 gre_update_hdr(sc, gh);
389
390 /*
391 * If we return error, this means that sc is not linked,
392 * and caller should reset gre_family and free(sc->gre_hdr).
393 */
394 if (sc->gre_options & GRE_UDPENCAP) {
395 error = in6_gre_setup_socket(sc);
396 if (error != 0)
397 return (error);
398 } else
399 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain);
400 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(&sc->gre_oip6.ip6_src), sc, srchash);
401
402 /* Set IFF_DRV_RUNNING if interface is ready */
403 in6_gre_set_running(sc);
404 return (0);
405 }
406
407 int
408 in6_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value)
409 {
410 int error;
411
412 /* NOTE: we are protected with gre_ioctl_sx lock */
413 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT);
414 MPASS(sc->gre_family == AF_INET6);
415
416 /*
417 * If we are going to change encapsulation protocol, do check
418 * for duplicate tunnels. Return EEXIST here to do not confuse
419 * user.
420 */
421 if (cmd == GRESOPTS &&
422 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) &&
423 in6_gre_checkdup(sc, &sc->gre_oip6.ip6_src,
424 &sc->gre_oip6.ip6_dst, value) == EADDRNOTAVAIL)
425 return (EEXIST);
426
427 CK_LIST_REMOVE(sc, chain);
428 CK_LIST_REMOVE(sc, srchash);
429 GRE_WAIT();
430 switch (cmd) {
431 case GRESKEY:
432 sc->gre_key = value;
433 break;
434 case GRESOPTS:
435 sc->gre_options = value;
436 break;
437 case GRESPORT:
438 sc->gre_port = value;
439 break;
440 }
441 error = in6_gre_attach(sc);
442 if (error != 0) {
443 sc->gre_family = 0;
444 free(sc->gre_hdr, M_GRE);
445 }
446 return (error);
447 }
448
449 int
450 in6_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data)
451 {
452 struct in6_ifreq *ifr = (struct in6_ifreq *)data;
453 struct sockaddr_in6 *dst, *src;
454 struct ip6_hdr *ip6;
455 int error;
456
457 /* NOTE: we are protected with gre_ioctl_sx lock */
458 error = EINVAL;
459 switch (cmd) {
460 case SIOCSIFPHYADDR_IN6:
461 src = &((struct in6_aliasreq *)data)->ifra_addr;
462 dst = &((struct in6_aliasreq *)data)->ifra_dstaddr;
463
464 /* sanity checks */
465 if (src->sin6_family != dst->sin6_family ||
466 src->sin6_family != AF_INET6 ||
467 src->sin6_len != dst->sin6_len ||
468 src->sin6_len != sizeof(*src))
469 break;
470 if (IN6_IS_ADDR_UNSPECIFIED(&src->sin6_addr) ||
471 IN6_IS_ADDR_UNSPECIFIED(&dst->sin6_addr)) {
472 error = EADDRNOTAVAIL;
473 break;
474 }
475 /*
476 * Check validity of the scope zone ID of the
477 * addresses, and convert it into the kernel
478 * internal form if necessary.
479 */
480 if ((error = sa6_embedscope(src, 0)) != 0 ||
481 (error = sa6_embedscope(dst, 0)) != 0)
482 break;
483
484 if (V_ipv6_hashtbl == NULL) {
485 V_ipv6_hashtbl = gre_hashinit();
486 V_ipv6_srchashtbl = gre_hashinit();
487 V_ipv6_sockets = (struct gre_sockets *)gre_hashinit();
488 }
489 error = in6_gre_checkdup(sc, &src->sin6_addr,
490 &dst->sin6_addr, sc->gre_options);
491 if (error == EADDRNOTAVAIL)
492 break;
493 if (error == EEXIST) {
494 /* Addresses are the same. Just return. */
495 error = 0;
496 break;
497 }
498 ip6 = malloc(sizeof(struct greudp6) + 3 * sizeof(uint32_t),
499 M_GRE, M_WAITOK | M_ZERO);
500 ip6->ip6_src = src->sin6_addr;
501 ip6->ip6_dst = dst->sin6_addr;
502 if (sc->gre_family != 0) {
503 /* Detach existing tunnel first */
504 CK_LIST_REMOVE(sc, chain);
505 CK_LIST_REMOVE(sc, srchash);
506 GRE_WAIT();
507 free(sc->gre_hdr, M_GRE);
508 /* XXX: should we notify about link state change? */
509 }
510 sc->gre_family = AF_INET6;
511 sc->gre_hdr = ip6;
512 sc->gre_oseq = 0;
513 sc->gre_iseq = UINT32_MAX;
514 error = in6_gre_attach(sc);
515 if (error != 0) {
516 sc->gre_family = 0;
517 free(sc->gre_hdr, M_GRE);
518 }
519 break;
520 case SIOCGIFPSRCADDR_IN6:
521 case SIOCGIFPDSTADDR_IN6:
522 if (sc->gre_family != AF_INET6) {
523 error = EADDRNOTAVAIL;
524 break;
525 }
526 src = (struct sockaddr_in6 *)&ifr->ifr_addr;
527 memset(src, 0, sizeof(*src));
528 src->sin6_family = AF_INET6;
529 src->sin6_len = sizeof(*src);
530 src->sin6_addr = (cmd == SIOCGIFPSRCADDR_IN6) ?
531 sc->gre_oip6.ip6_src: sc->gre_oip6.ip6_dst;
532 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
533 if (error == 0)
534 error = sa6_recoverscope(src);
535 if (error != 0)
536 memset(src, 0, sizeof(*src));
537 break;
538 }
539 return (error);
540 }
541
542 int
543 in6_gre_output(struct mbuf *m, int af __unused, int hlen __unused,
544 uint32_t flowid)
545 {
546 struct greip6 *gi6;
547
548 gi6 = mtod(m, struct greip6 *);
549 gi6->gi6_ip6.ip6_hlim = V_ip6_gre_hlim;
550 gi6->gi6_ip6.ip6_flow |= flowid & IPV6_FLOWLABEL_MASK;
551 return (ip6_output(m, NULL, NULL, IPV6_MINMTU, NULL, NULL, NULL));
552 }
553
554 static const struct srcaddrtab *ipv6_srcaddrtab = NULL;
555 static const struct encaptab *ecookie = NULL;
556 static const struct encap_config ipv6_encap_cfg = {
557 .proto = IPPROTO_GRE,
558 .min_length = sizeof(struct greip6) +
559 #ifdef INET
560 sizeof(struct ip),
561 #else
562 sizeof(struct ip6_hdr),
563 #endif
564 .exact_match = ENCAP_DRV_LOOKUP,
565 .lookup = in6_gre_lookup,
566 .input = gre_input
567 };
568
569 void
570 in6_gre_init(void)
571 {
572
573 if (!IS_DEFAULT_VNET(curvnet))
574 return;
575 ipv6_srcaddrtab = ip6_encap_register_srcaddr(in6_gre_srcaddr,
576 NULL, M_WAITOK);
577 ecookie = ip6_encap_attach(&ipv6_encap_cfg, NULL, M_WAITOK);
578 }
579
580 void
581 in6_gre_uninit(void)
582 {
583
584 if (IS_DEFAULT_VNET(curvnet)) {
585 ip6_encap_detach(ecookie);
586 ip6_encap_unregister_srcaddr(ipv6_srcaddrtab);
587 }
588 if (V_ipv6_hashtbl != NULL) {
589 gre_hashdestroy(V_ipv6_hashtbl);
590 V_ipv6_hashtbl = NULL;
591 GRE_WAIT();
592 gre_hashdestroy(V_ipv6_srchashtbl);
593 gre_hashdestroy((struct gre_list *)V_ipv6_sockets);
594 }
595 }
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