1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-NetBSD
3 *
4 * Copyright (c) 1998 The NetBSD Foundation, Inc.
5 * Copyright (c) 2014, 2018 Andrey V. Elsukov <[email protected]>
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Heiko W.Rupp <[email protected]>
10 *
11 * IPv6-over-GRE contributed by Gert Doering <[email protected]>
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
24 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
25 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
26 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
33 *
34 * $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39
40 #include "opt_inet.h"
41 #include "opt_inet6.h"
42
43 #include <sys/param.h>
44 #include <sys/jail.h>
45 #include <sys/systm.h>
46 #include <sys/socket.h>
47 #include <sys/socketvar.h>
48 #include <sys/sockio.h>
49 #include <sys/mbuf.h>
50 #include <sys/errno.h>
51 #include <sys/kernel.h>
52 #include <sys/sysctl.h>
53 #include <sys/malloc.h>
54 #include <sys/proc.h>
55
56 #include <net/if.h>
57 #include <net/if_var.h>
58 #include <net/vnet.h>
59
60 #include <netinet/in.h>
61 #include <netinet/in_var.h>
62 #include <netinet/in_pcb.h>
63 #include <netinet/ip.h>
64 #include <netinet/ip_encap.h>
65 #include <netinet/ip_var.h>
66 #include <netinet/udp.h>
67 #include <netinet/udp_var.h>
68
69 #ifdef INET6
70 #include <netinet/ip6.h>
71 #endif
72
73 #include <net/if_gre.h>
74 #include <machine/in_cksum.h>
75
76 #define GRE_TTL 30
77 VNET_DEFINE(int, ip_gre_ttl) = GRE_TTL;
78 #define V_ip_gre_ttl VNET(ip_gre_ttl)
79 SYSCTL_INT(_net_inet_ip, OID_AUTO, grettl, CTLFLAG_VNET | CTLFLAG_RW,
80 &VNET_NAME(ip_gre_ttl), 0, "Default TTL value for encapsulated packets");
81
82 struct in_gre_socket {
83 struct gre_socket base;
84 in_addr_t addr;
85 };
86 VNET_DEFINE_STATIC(struct gre_sockets *, ipv4_sockets) = NULL;
87 VNET_DEFINE_STATIC(struct gre_list *, ipv4_hashtbl) = NULL;
88 VNET_DEFINE_STATIC(struct gre_list *, ipv4_srchashtbl) = NULL;
89 #define V_ipv4_sockets VNET(ipv4_sockets)
90 #define V_ipv4_hashtbl VNET(ipv4_hashtbl)
91 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl)
92 #define GRE_HASH(src, dst) (V_ipv4_hashtbl[\
93 in_gre_hashval((src), (dst)) & (GRE_HASH_SIZE - 1)])
94 #define GRE_SRCHASH(src) (V_ipv4_srchashtbl[\
95 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)])
96 #define GRE_SOCKHASH(src) (V_ipv4_sockets[\
97 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)])
98 #define GRE_HASH_SC(sc) GRE_HASH((sc)->gre_oip.ip_src.s_addr,\
99 (sc)->gre_oip.ip_dst.s_addr)
100
101 static uint32_t
in_gre_hashval(in_addr_t src,in_addr_t dst)102 in_gre_hashval(in_addr_t src, in_addr_t dst)
103 {
104 uint32_t ret;
105
106 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
107 return (fnv_32_buf(&dst, sizeof(dst), ret));
108 }
109
110 static struct gre_socket*
in_gre_lookup_socket(in_addr_t addr)111 in_gre_lookup_socket(in_addr_t addr)
112 {
113 struct gre_socket *gs;
114 struct in_gre_socket *s;
115
116 CK_LIST_FOREACH(gs, &GRE_SOCKHASH(addr), chain) {
117 s = __containerof(gs, struct in_gre_socket, base);
118 if (s->addr == addr)
119 break;
120 }
121 return (gs);
122 }
123
124 static int
in_gre_checkdup(const struct gre_softc * sc,in_addr_t src,in_addr_t dst,uint32_t opts)125 in_gre_checkdup(const struct gre_softc *sc, in_addr_t src, in_addr_t dst,
126 uint32_t opts)
127 {
128 struct gre_list *head;
129 struct gre_softc *tmp;
130 struct gre_socket *gs;
131
132 if (sc->gre_family == AF_INET &&
133 sc->gre_oip.ip_src.s_addr == src &&
134 sc->gre_oip.ip_dst.s_addr == dst &&
135 (sc->gre_options & GRE_UDPENCAP) == (opts & GRE_UDPENCAP))
136 return (EEXIST);
137
138 if (opts & GRE_UDPENCAP) {
139 gs = in_gre_lookup_socket(src);
140 if (gs == NULL)
141 return (0);
142 head = &gs->list;
143 } else
144 head = &GRE_HASH(src, dst);
145
146 CK_LIST_FOREACH(tmp, head, chain) {
147 if (tmp == sc)
148 continue;
149 if (tmp->gre_oip.ip_src.s_addr == src &&
150 tmp->gre_oip.ip_dst.s_addr == dst)
151 return (EADDRNOTAVAIL);
152 }
153 return (0);
154 }
155
156 static int
in_gre_lookup(const struct mbuf * m,int off,int proto,void ** arg)157 in_gre_lookup(const struct mbuf *m, int off, int proto, void **arg)
158 {
159 const struct ip *ip;
160 struct gre_softc *sc;
161
162 if (V_ipv4_hashtbl == NULL)
163 return (0);
164
165 NET_EPOCH_ASSERT();
166 ip = mtod(m, const struct ip *);
167 CK_LIST_FOREACH(sc, &GRE_HASH(ip->ip_dst.s_addr,
168 ip->ip_src.s_addr), chain) {
169 /*
170 * This is an inbound packet, its ip_dst is source address
171 * in softc.
172 */
173 if (sc->gre_oip.ip_src.s_addr == ip->ip_dst.s_addr &&
174 sc->gre_oip.ip_dst.s_addr == ip->ip_src.s_addr) {
175 if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0)
176 return (0);
177 *arg = sc;
178 return (ENCAP_DRV_LOOKUP);
179 }
180 }
181 return (0);
182 }
183
184 /*
185 * Check that ingress address belongs to local host.
186 */
187 static void
in_gre_set_running(struct gre_softc * sc)188 in_gre_set_running(struct gre_softc *sc)
189 {
190
191 if (in_localip(sc->gre_oip.ip_src))
192 GRE2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
193 else
194 GRE2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
195 }
196
197 /*
198 * ifaddr_event handler.
199 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
200 * source address spoofing.
201 */
202 static void
in_gre_srcaddr(void * arg __unused,const struct sockaddr * sa,int event __unused)203 in_gre_srcaddr(void *arg __unused, const struct sockaddr *sa,
204 int event __unused)
205 {
206 const struct sockaddr_in *sin;
207 struct gre_softc *sc;
208
209 /* Check that VNET is ready */
210 if (V_ipv4_hashtbl == NULL)
211 return;
212
213 NET_EPOCH_ASSERT();
214 sin = (const struct sockaddr_in *)sa;
215 CK_LIST_FOREACH(sc, &GRE_SRCHASH(sin->sin_addr.s_addr), srchash) {
216 if (sc->gre_oip.ip_src.s_addr != sin->sin_addr.s_addr)
217 continue;
218 in_gre_set_running(sc);
219 }
220 }
221
222 static void
in_gre_udp_input(struct mbuf * m,int off,struct inpcb * inp,const struct sockaddr * sa,void * ctx)223 in_gre_udp_input(struct mbuf *m, int off, struct inpcb *inp,
224 const struct sockaddr *sa, void *ctx)
225 {
226 struct epoch_tracker et;
227 struct gre_socket *gs;
228 struct gre_softc *sc;
229 in_addr_t dst;
230
231 NET_EPOCH_ENTER(et);
232 /*
233 * udp_append() holds reference to inp, it is safe to check
234 * inp_flags2 without INP_RLOCK().
235 * If socket was closed before we have entered NET_EPOCH section,
236 * INP_FREED flag should be set. Otherwise it should be safe to
237 * make access to ctx data, because gre_so will be freed by
238 * gre_sofree() via NET_EPOCH_CALL().
239 */
240 if (__predict_false(inp->inp_flags2 & INP_FREED)) {
241 NET_EPOCH_EXIT(et);
242 m_freem(m);
243 return;
244 }
245
246 gs = (struct gre_socket *)ctx;
247 dst = ((const struct sockaddr_in *)sa)->sin_addr.s_addr;
248 CK_LIST_FOREACH(sc, &gs->list, chain) {
249 if (sc->gre_oip.ip_dst.s_addr == dst)
250 break;
251 }
252 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){
253 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc);
254 NET_EPOCH_EXIT(et);
255 return;
256 }
257 m_freem(m);
258 NET_EPOCH_EXIT(et);
259 }
260
261 static int
in_gre_setup_socket(struct gre_softc * sc)262 in_gre_setup_socket(struct gre_softc *sc)
263 {
264 struct sockopt sopt;
265 struct sockaddr_in sin;
266 struct in_gre_socket *s;
267 struct gre_socket *gs;
268 in_addr_t addr;
269 int error, value;
270
271 /*
272 * NOTE: we are protected with gre_ioctl_sx lock.
273 *
274 * First check that socket is already configured.
275 * If so, check that source addres was not changed.
276 * If address is different, check that there are no other tunnels
277 * and close socket.
278 */
279 addr = sc->gre_oip.ip_src.s_addr;
280 gs = sc->gre_so;
281 if (gs != NULL) {
282 s = __containerof(gs, struct in_gre_socket, base);
283 if (s->addr != addr) {
284 if (CK_LIST_EMPTY(&gs->list)) {
285 CK_LIST_REMOVE(gs, chain);
286 soclose(gs->so);
287 NET_EPOCH_CALL(gre_sofree, &gs->epoch_ctx);
288 }
289 gs = sc->gre_so = NULL;
290 }
291 }
292
293 if (gs == NULL) {
294 /*
295 * Check that socket for given address is already
296 * configured.
297 */
298 gs = in_gre_lookup_socket(addr);
299 if (gs == NULL) {
300 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO);
301 s->addr = addr;
302 gs = &s->base;
303
304 error = socreate(sc->gre_family, &gs->so,
305 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred,
306 curthread);
307 if (error != 0) {
308 if_printf(GRE2IFP(sc),
309 "cannot create socket: %d\n", error);
310 free(s, M_GRE);
311 return (error);
312 }
313
314 error = udp_set_kernel_tunneling(gs->so,
315 in_gre_udp_input, NULL, gs);
316 if (error != 0) {
317 if_printf(GRE2IFP(sc),
318 "cannot set UDP tunneling: %d\n", error);
319 goto fail;
320 }
321
322 memset(&sopt, 0, sizeof(sopt));
323 sopt.sopt_dir = SOPT_SET;
324 sopt.sopt_level = IPPROTO_IP;
325 sopt.sopt_name = IP_BINDANY;
326 sopt.sopt_val = &value;
327 sopt.sopt_valsize = sizeof(value);
328 value = 1;
329 error = sosetopt(gs->so, &sopt);
330 if (error != 0) {
331 if_printf(GRE2IFP(sc),
332 "cannot set IP_BINDANY opt: %d\n", error);
333 goto fail;
334 }
335
336 memset(&sin, 0, sizeof(sin));
337 sin.sin_family = AF_INET;
338 sin.sin_len = sizeof(sin);
339 sin.sin_addr.s_addr = addr;
340 sin.sin_port = htons(GRE_UDPPORT);
341 error = sobind(gs->so, (struct sockaddr *)&sin,
342 curthread);
343 if (error != 0) {
344 if_printf(GRE2IFP(sc),
345 "cannot bind socket: %d\n", error);
346 goto fail;
347 }
348 /* Add socket to the chain */
349 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain);
350 }
351 }
352
353 /* Add softc to the socket's list */
354 CK_LIST_INSERT_HEAD(&gs->list, sc, chain);
355 sc->gre_so = gs;
356 return (0);
357 fail:
358 soclose(gs->so);
359 free(s, M_GRE);
360 return (error);
361 }
362
363 static int
in_gre_attach(struct gre_softc * sc)364 in_gre_attach(struct gre_softc *sc)
365 {
366 struct grehdr *gh;
367 int error;
368
369 if (sc->gre_options & GRE_UDPENCAP) {
370 sc->gre_csumflags = CSUM_UDP;
371 sc->gre_hlen = sizeof(struct greudp);
372 sc->gre_oip.ip_p = IPPROTO_UDP;
373 gh = &sc->gre_udphdr->gi_gre;
374 gre_update_udphdr(sc, &sc->gre_udp,
375 in_pseudo(sc->gre_oip.ip_src.s_addr,
376 sc->gre_oip.ip_dst.s_addr, 0));
377 } else {
378 sc->gre_hlen = sizeof(struct greip);
379 sc->gre_oip.ip_p = IPPROTO_GRE;
380 gh = &sc->gre_iphdr->gi_gre;
381 }
382 sc->gre_oip.ip_v = IPVERSION;
383 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2;
384 gre_update_hdr(sc, gh);
385
386 /*
387 * If we return error, this means that sc is not linked,
388 * and caller should reset gre_family and free(sc->gre_hdr).
389 */
390 if (sc->gre_options & GRE_UDPENCAP) {
391 error = in_gre_setup_socket(sc);
392 if (error != 0)
393 return (error);
394 } else
395 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain);
396 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr),
397 sc, srchash);
398
399 /* Set IFF_DRV_RUNNING if interface is ready */
400 in_gre_set_running(sc);
401 return (0);
402 }
403
404 int
in_gre_setopts(struct gre_softc * sc,u_long cmd,uint32_t value)405 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value)
406 {
407 int error;
408
409 /* NOTE: we are protected with gre_ioctl_sx lock */
410 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT);
411 MPASS(sc->gre_family == AF_INET);
412
413 /*
414 * If we are going to change encapsulation protocol, do check
415 * for duplicate tunnels. Return EEXIST here to do not confuse
416 * user.
417 */
418 if (cmd == GRESOPTS &&
419 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) &&
420 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr,
421 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL)
422 return (EEXIST);
423
424 CK_LIST_REMOVE(sc, chain);
425 CK_LIST_REMOVE(sc, srchash);
426 GRE_WAIT();
427 switch (cmd) {
428 case GRESKEY:
429 sc->gre_key = value;
430 break;
431 case GRESOPTS:
432 sc->gre_options = value;
433 break;
434 case GRESPORT:
435 sc->gre_port = value;
436 break;
437 }
438 error = in_gre_attach(sc);
439 if (error != 0) {
440 sc->gre_family = 0;
441 free(sc->gre_hdr, M_GRE);
442 }
443 return (error);
444 }
445
446 int
in_gre_ioctl(struct gre_softc * sc,u_long cmd,caddr_t data)447 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data)
448 {
449 struct ifreq *ifr = (struct ifreq *)data;
450 struct sockaddr_in *dst, *src;
451 struct ip *ip;
452 int error;
453
454 /* NOTE: we are protected with gre_ioctl_sx lock */
455 error = EINVAL;
456 switch (cmd) {
457 case SIOCSIFPHYADDR:
458 src = &((struct in_aliasreq *)data)->ifra_addr;
459 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
460
461 /* sanity checks */
462 if (src->sin_family != dst->sin_family ||
463 src->sin_family != AF_INET ||
464 src->sin_len != dst->sin_len ||
465 src->sin_len != sizeof(*src))
466 break;
467 if (src->sin_addr.s_addr == INADDR_ANY ||
468 dst->sin_addr.s_addr == INADDR_ANY) {
469 error = EADDRNOTAVAIL;
470 break;
471 }
472 if (V_ipv4_hashtbl == NULL) {
473 V_ipv4_hashtbl = gre_hashinit();
474 V_ipv4_srchashtbl = gre_hashinit();
475 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit();
476 }
477 error = in_gre_checkdup(sc, src->sin_addr.s_addr,
478 dst->sin_addr.s_addr, sc->gre_options);
479 if (error == EADDRNOTAVAIL)
480 break;
481 if (error == EEXIST) {
482 /* Addresses are the same. Just return. */
483 error = 0;
484 break;
485 }
486 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t),
487 M_GRE, M_WAITOK | M_ZERO);
488 ip->ip_src.s_addr = src->sin_addr.s_addr;
489 ip->ip_dst.s_addr = dst->sin_addr.s_addr;
490 if (sc->gre_family != 0) {
491 /* Detach existing tunnel first */
492 CK_LIST_REMOVE(sc, chain);
493 CK_LIST_REMOVE(sc, srchash);
494 GRE_WAIT();
495 free(sc->gre_hdr, M_GRE);
496 /* XXX: should we notify about link state change? */
497 }
498 sc->gre_family = AF_INET;
499 sc->gre_hdr = ip;
500 sc->gre_oseq = 0;
501 sc->gre_iseq = UINT32_MAX;
502 error = in_gre_attach(sc);
503 if (error != 0) {
504 sc->gre_family = 0;
505 free(sc->gre_hdr, M_GRE);
506 }
507 break;
508 case SIOCGIFPSRCADDR:
509 case SIOCGIFPDSTADDR:
510 if (sc->gre_family != AF_INET) {
511 error = EADDRNOTAVAIL;
512 break;
513 }
514 src = (struct sockaddr_in *)&ifr->ifr_addr;
515 memset(src, 0, sizeof(*src));
516 src->sin_family = AF_INET;
517 src->sin_len = sizeof(*src);
518 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
519 sc->gre_oip.ip_src: sc->gre_oip.ip_dst;
520 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
521 if (error != 0)
522 memset(src, 0, sizeof(*src));
523 break;
524 }
525 return (error);
526 }
527
528 int
in_gre_output(struct mbuf * m,int af,int hlen)529 in_gre_output(struct mbuf *m, int af, int hlen)
530 {
531 struct greip *gi;
532
533 gi = mtod(m, struct greip *);
534 switch (af) {
535 case AF_INET:
536 /*
537 * gre_transmit() has used M_PREPEND() that doesn't guarantee
538 * m_data is contiguous more than hlen bytes. Use m_copydata()
539 * here to avoid m_pullup().
540 */
541 m_copydata(m, hlen + offsetof(struct ip, ip_tos),
542 sizeof(u_char), &gi->gi_ip.ip_tos);
543 m_copydata(m, hlen + offsetof(struct ip, ip_id),
544 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id);
545 break;
546 #ifdef INET6
547 case AF_INET6:
548 gi->gi_ip.ip_tos = 0; /* XXX */
549 ip_fillid(&gi->gi_ip);
550 break;
551 #endif
552 }
553 gi->gi_ip.ip_ttl = V_ip_gre_ttl;
554 gi->gi_ip.ip_len = htons(m->m_pkthdr.len);
555 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL));
556 }
557
558 static const struct srcaddrtab *ipv4_srcaddrtab = NULL;
559 static const struct encaptab *ecookie = NULL;
560 static const struct encap_config ipv4_encap_cfg = {
561 .proto = IPPROTO_GRE,
562 .min_length = sizeof(struct greip) + sizeof(struct ip),
563 .exact_match = ENCAP_DRV_LOOKUP,
564 .lookup = in_gre_lookup,
565 .input = gre_input
566 };
567
568 void
in_gre_init(void)569 in_gre_init(void)
570 {
571
572 if (!IS_DEFAULT_VNET(curvnet))
573 return;
574 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr,
575 NULL, M_WAITOK);
576 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
577 }
578
579 void
in_gre_uninit(void)580 in_gre_uninit(void)
581 {
582
583 if (IS_DEFAULT_VNET(curvnet)) {
584 ip_encap_detach(ecookie);
585 ip_encap_unregister_srcaddr(ipv4_srcaddrtab);
586 }
587 if (V_ipv4_hashtbl != NULL) {
588 gre_hashdestroy(V_ipv4_hashtbl);
589 V_ipv4_hashtbl = NULL;
590 GRE_WAIT();
591 gre_hashdestroy(V_ipv4_srchashtbl);
592 gre_hashdestroy((struct gre_list *)V_ipv4_sockets);
593 }
594 }
595