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