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/if_private.h>
57 #include <net/vnet.h>
58
59 #include <netinet/in.h>
60 #include <netinet/in_var.h>
61 #include <netinet/in_pcb.h>
62 #include <netinet/ip.h>
63 #include <netinet/ip_encap.h>
64 #include <netinet/ip_var.h>
65 #include <netinet/udp.h>
66 #include <netinet/udp_var.h>
67
68 #ifdef INET6
69 #include <netinet/ip6.h>
70 #endif
71
72 #include <net/if_gre.h>
73 #include <machine/in_cksum.h>
74
75 #define GRE_TTL 30
76 VNET_DEFINE(int, ip_gre_ttl) = GRE_TTL;
77 #define V_ip_gre_ttl VNET(ip_gre_ttl)
78 SYSCTL_INT(_net_inet_ip, OID_AUTO, grettl, CTLFLAG_VNET | CTLFLAG_RW,
79 &VNET_NAME(ip_gre_ttl), 0, "Default TTL value for encapsulated packets");
80
81 struct in_gre_socket {
82 struct gre_socket base;
83 in_addr_t addr;
84 };
85 VNET_DEFINE_STATIC(struct gre_sockets *, ipv4_sockets) = NULL;
86 VNET_DEFINE_STATIC(struct gre_list *, ipv4_hashtbl) = NULL;
87 VNET_DEFINE_STATIC(struct gre_list *, ipv4_srchashtbl) = NULL;
88 #define V_ipv4_sockets VNET(ipv4_sockets)
89 #define V_ipv4_hashtbl VNET(ipv4_hashtbl)
90 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl)
91 #define GRE_HASH(src, dst) (V_ipv4_hashtbl[\
92 in_gre_hashval((src), (dst)) & (GRE_HASH_SIZE - 1)])
93 #define GRE_SRCHASH(src) (V_ipv4_srchashtbl[\
94 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)])
95 #define GRE_SOCKHASH(src) (V_ipv4_sockets[\
96 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)])
97 #define GRE_HASH_SC(sc) GRE_HASH((sc)->gre_oip.ip_src.s_addr,\
98 (sc)->gre_oip.ip_dst.s_addr)
99
100 static uint32_t
in_gre_hashval(in_addr_t src,in_addr_t dst)101 in_gre_hashval(in_addr_t src, in_addr_t dst)
102 {
103 uint32_t ret;
104
105 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
106 return (fnv_32_buf(&dst, sizeof(dst), ret));
107 }
108
109 static struct gre_socket*
in_gre_lookup_socket(in_addr_t addr)110 in_gre_lookup_socket(in_addr_t addr)
111 {
112 struct gre_socket *gs;
113 struct in_gre_socket *s;
114
115 CK_LIST_FOREACH(gs, &GRE_SOCKHASH(addr), chain) {
116 s = __containerof(gs, struct in_gre_socket, base);
117 if (s->addr == addr)
118 break;
119 }
120 return (gs);
121 }
122
123 static int
in_gre_checkdup(const struct gre_softc * sc,in_addr_t src,in_addr_t dst,uint32_t opts)124 in_gre_checkdup(const struct gre_softc *sc, in_addr_t src, in_addr_t dst,
125 uint32_t opts)
126 {
127 struct gre_list *head;
128 struct gre_softc *tmp;
129 struct gre_socket *gs;
130
131 if (sc->gre_family == AF_INET &&
132 sc->gre_oip.ip_src.s_addr == src &&
133 sc->gre_oip.ip_dst.s_addr == dst &&
134 (sc->gre_options & GRE_UDPENCAP) == (opts & GRE_UDPENCAP))
135 return (EEXIST);
136
137 if (opts & GRE_UDPENCAP) {
138 gs = in_gre_lookup_socket(src);
139 if (gs == NULL)
140 return (0);
141 head = &gs->list;
142 } else
143 head = &GRE_HASH(src, dst);
144
145 CK_LIST_FOREACH(tmp, head, chain) {
146 if (tmp == sc)
147 continue;
148 if (tmp->gre_oip.ip_src.s_addr == src &&
149 tmp->gre_oip.ip_dst.s_addr == dst)
150 return (EADDRNOTAVAIL);
151 }
152 return (0);
153 }
154
155 static int
in_gre_lookup(const struct mbuf * m,int off,int proto,void ** arg)156 in_gre_lookup(const struct mbuf *m, int off, int proto, void **arg)
157 {
158 const struct ip *ip;
159 struct gre_softc *sc;
160
161 if (V_ipv4_hashtbl == NULL)
162 return (0);
163
164 NET_EPOCH_ASSERT();
165 ip = mtod(m, const struct ip *);
166 CK_LIST_FOREACH(sc, &GRE_HASH(ip->ip_dst.s_addr,
167 ip->ip_src.s_addr), chain) {
168 /*
169 * This is an inbound packet, its ip_dst is source address
170 * in softc.
171 */
172 if (sc->gre_oip.ip_src.s_addr == ip->ip_dst.s_addr &&
173 sc->gre_oip.ip_dst.s_addr == ip->ip_src.s_addr) {
174 if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0)
175 return (0);
176 *arg = sc;
177 return (ENCAP_DRV_LOOKUP);
178 }
179 }
180 return (0);
181 }
182
183 /*
184 * Check that ingress address belongs to local host.
185 */
186 static void
in_gre_set_running(struct gre_softc * sc)187 in_gre_set_running(struct gre_softc *sc)
188 {
189
190 if (in_localip(sc->gre_oip.ip_src))
191 GRE2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
192 else
193 GRE2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
194 }
195
196 /*
197 * ifaddr_event handler.
198 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
199 * source address spoofing.
200 */
201 static void
in_gre_srcaddr(void * arg __unused,const struct sockaddr * sa,int event __unused)202 in_gre_srcaddr(void *arg __unused, const struct sockaddr *sa,
203 int event __unused)
204 {
205 const struct sockaddr_in *sin;
206 struct gre_softc *sc;
207
208 /* Check that VNET is ready */
209 if (V_ipv4_hashtbl == NULL)
210 return;
211
212 NET_EPOCH_ASSERT();
213 sin = (const struct sockaddr_in *)sa;
214 CK_LIST_FOREACH(sc, &GRE_SRCHASH(sin->sin_addr.s_addr), srchash) {
215 if (sc->gre_oip.ip_src.s_addr != sin->sin_addr.s_addr)
216 continue;
217 in_gre_set_running(sc);
218 }
219 }
220
221 static bool
in_gre_udp_input(struct mbuf * m,int off,struct inpcb * inp,const struct sockaddr * sa,void * ctx)222 in_gre_udp_input(struct mbuf *m, int off, struct inpcb *inp,
223 const struct sockaddr *sa, void *ctx)
224 {
225 struct gre_socket *gs;
226 struct gre_softc *sc;
227 in_addr_t dst;
228
229 NET_EPOCH_ASSERT();
230
231 gs = (struct gre_socket *)ctx;
232 dst = ((const struct sockaddr_in *)sa)->sin_addr.s_addr;
233 CK_LIST_FOREACH(sc, &gs->list, chain) {
234 if (sc->gre_oip.ip_dst.s_addr == dst)
235 break;
236 }
237 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){
238 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc);
239 return (true);
240 }
241 m_freem(m);
242
243 return (true);
244 }
245
246 static int
in_gre_setup_socket(struct gre_softc * sc)247 in_gre_setup_socket(struct gre_softc *sc)
248 {
249 struct sockopt sopt;
250 struct sockaddr_in sin;
251 struct in_gre_socket *s;
252 struct gre_socket *gs;
253 in_addr_t addr;
254 int error, value;
255
256 /*
257 * NOTE: we are protected with gre_ioctl_sx lock.
258 *
259 * First check that socket is already configured.
260 * If so, check that source address was not changed.
261 * If address is different, check that there are no other tunnels
262 * and close socket.
263 */
264 addr = sc->gre_oip.ip_src.s_addr;
265 gs = sc->gre_so;
266 if (gs != NULL) {
267 s = __containerof(gs, struct in_gre_socket, base);
268 if (s->addr != addr) {
269 if (CK_LIST_EMPTY(&gs->list)) {
270 CK_LIST_REMOVE(gs, chain);
271 soclose(gs->so);
272 NET_EPOCH_CALL(gre_sofree, &gs->epoch_ctx);
273 }
274 gs = sc->gre_so = NULL;
275 }
276 }
277
278 if (gs == NULL) {
279 /*
280 * Check that socket for given address is already
281 * configured.
282 */
283 gs = in_gre_lookup_socket(addr);
284 if (gs == NULL) {
285 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO);
286 s->addr = addr;
287 gs = &s->base;
288
289 error = socreate(sc->gre_family, &gs->so,
290 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred,
291 curthread);
292 if (error != 0) {
293 if_printf(GRE2IFP(sc),
294 "cannot create socket: %d\n", error);
295 free(s, M_GRE);
296 return (error);
297 }
298
299 error = udp_set_kernel_tunneling(gs->so,
300 in_gre_udp_input, NULL, gs);
301 if (error != 0) {
302 if_printf(GRE2IFP(sc),
303 "cannot set UDP tunneling: %d\n", error);
304 goto fail;
305 }
306
307 memset(&sopt, 0, sizeof(sopt));
308 sopt.sopt_dir = SOPT_SET;
309 sopt.sopt_level = IPPROTO_IP;
310 sopt.sopt_name = IP_BINDANY;
311 sopt.sopt_val = &value;
312 sopt.sopt_valsize = sizeof(value);
313 value = 1;
314 error = sosetopt(gs->so, &sopt);
315 if (error != 0) {
316 if_printf(GRE2IFP(sc),
317 "cannot set IP_BINDANY opt: %d\n", error);
318 goto fail;
319 }
320
321 memset(&sin, 0, sizeof(sin));
322 sin.sin_family = AF_INET;
323 sin.sin_len = sizeof(sin);
324 sin.sin_addr.s_addr = addr;
325 sin.sin_port = htons(GRE_UDPPORT);
326 error = sobind(gs->so, (struct sockaddr *)&sin,
327 curthread);
328 if (error != 0) {
329 if_printf(GRE2IFP(sc),
330 "cannot bind socket: %d\n", error);
331 goto fail;
332 }
333 /* Add socket to the chain */
334 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain);
335 }
336 }
337
338 /* Add softc to the socket's list */
339 CK_LIST_INSERT_HEAD(&gs->list, sc, chain);
340 sc->gre_so = gs;
341 return (0);
342 fail:
343 soclose(gs->so);
344 free(s, M_GRE);
345 return (error);
346 }
347
348 static int
in_gre_attach(struct gre_softc * sc)349 in_gre_attach(struct gre_softc *sc)
350 {
351 struct epoch_tracker et;
352 struct grehdr *gh;
353 int error;
354
355 if (sc->gre_options & GRE_UDPENCAP) {
356 sc->gre_csumflags = CSUM_UDP;
357 sc->gre_hlen = sizeof(struct greudp);
358 sc->gre_oip.ip_p = IPPROTO_UDP;
359 gh = &sc->gre_udphdr->gi_gre;
360 gre_update_udphdr(sc, &sc->gre_udp,
361 in_pseudo(sc->gre_oip.ip_src.s_addr,
362 sc->gre_oip.ip_dst.s_addr, 0));
363 } else {
364 sc->gre_hlen = sizeof(struct greip);
365 sc->gre_oip.ip_p = IPPROTO_GRE;
366 gh = &sc->gre_iphdr->gi_gre;
367 }
368 sc->gre_oip.ip_v = IPVERSION;
369 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2;
370 gre_update_hdr(sc, gh);
371
372 /*
373 * If we return error, this means that sc is not linked,
374 * and caller should reset gre_family and free(sc->gre_hdr).
375 */
376 if (sc->gre_options & GRE_UDPENCAP) {
377 error = in_gre_setup_socket(sc);
378 if (error != 0)
379 return (error);
380 } else
381 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain);
382 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr),
383 sc, srchash);
384
385 /* Set IFF_DRV_RUNNING if interface is ready */
386 NET_EPOCH_ENTER(et);
387 in_gre_set_running(sc);
388 NET_EPOCH_EXIT(et);
389 return (0);
390 }
391
392 int
in_gre_setopts(struct gre_softc * sc,u_long cmd,uint32_t value)393 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value)
394 {
395 int error;
396
397 /* NOTE: we are protected with gre_ioctl_sx lock */
398 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT);
399 MPASS(sc->gre_family == AF_INET);
400
401 /*
402 * If we are going to change encapsulation protocol, do check
403 * for duplicate tunnels. Return EEXIST here to do not confuse
404 * user.
405 */
406 if (cmd == GRESOPTS &&
407 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) &&
408 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr,
409 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL)
410 return (EEXIST);
411
412 CK_LIST_REMOVE(sc, chain);
413 CK_LIST_REMOVE(sc, srchash);
414 GRE_WAIT();
415 switch (cmd) {
416 case GRESKEY:
417 sc->gre_key = value;
418 break;
419 case GRESOPTS:
420 sc->gre_options = value;
421 break;
422 case GRESPORT:
423 sc->gre_port = value;
424 break;
425 }
426 error = in_gre_attach(sc);
427 if (error != 0) {
428 sc->gre_family = 0;
429 free(sc->gre_hdr, M_GRE);
430 }
431 return (error);
432 }
433
434 int
in_gre_ioctl(struct gre_softc * sc,u_long cmd,caddr_t data)435 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data)
436 {
437 struct ifreq *ifr = (struct ifreq *)data;
438 struct sockaddr_in *dst, *src;
439 struct ip *ip;
440 int error;
441
442 /* NOTE: we are protected with gre_ioctl_sx lock */
443 error = EINVAL;
444 switch (cmd) {
445 case SIOCSIFPHYADDR:
446 src = &((struct in_aliasreq *)data)->ifra_addr;
447 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
448
449 /* sanity checks */
450 if (src->sin_family != dst->sin_family ||
451 src->sin_family != AF_INET ||
452 src->sin_len != dst->sin_len ||
453 src->sin_len != sizeof(*src))
454 break;
455 if (src->sin_addr.s_addr == INADDR_ANY ||
456 dst->sin_addr.s_addr == INADDR_ANY) {
457 error = EADDRNOTAVAIL;
458 break;
459 }
460 if (V_ipv4_hashtbl == NULL) {
461 V_ipv4_hashtbl = gre_hashinit();
462 V_ipv4_srchashtbl = gre_hashinit();
463 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit();
464 }
465 error = in_gre_checkdup(sc, src->sin_addr.s_addr,
466 dst->sin_addr.s_addr, sc->gre_options);
467 if (error == EADDRNOTAVAIL)
468 break;
469 if (error == EEXIST) {
470 /* Addresses are the same. Just return. */
471 error = 0;
472 break;
473 }
474 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t),
475 M_GRE, M_WAITOK | M_ZERO);
476 ip->ip_src.s_addr = src->sin_addr.s_addr;
477 ip->ip_dst.s_addr = dst->sin_addr.s_addr;
478 if (sc->gre_family != 0) {
479 /* Detach existing tunnel first */
480 CK_LIST_REMOVE(sc, chain);
481 CK_LIST_REMOVE(sc, srchash);
482 GRE_WAIT();
483 free(sc->gre_hdr, M_GRE);
484 /* XXX: should we notify about link state change? */
485 }
486 sc->gre_family = AF_INET;
487 sc->gre_hdr = ip;
488 sc->gre_oseq = 0;
489 sc->gre_iseq = UINT32_MAX;
490 error = in_gre_attach(sc);
491 if (error != 0) {
492 sc->gre_family = 0;
493 free(sc->gre_hdr, M_GRE);
494 }
495 break;
496 case SIOCGIFPSRCADDR:
497 case SIOCGIFPDSTADDR:
498 if (sc->gre_family != AF_INET) {
499 error = EADDRNOTAVAIL;
500 break;
501 }
502 src = (struct sockaddr_in *)&ifr->ifr_addr;
503 memset(src, 0, sizeof(*src));
504 src->sin_family = AF_INET;
505 src->sin_len = sizeof(*src);
506 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
507 sc->gre_oip.ip_src: sc->gre_oip.ip_dst;
508 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
509 if (error != 0)
510 memset(src, 0, sizeof(*src));
511 break;
512 }
513 return (error);
514 }
515
516 int
in_gre_output(struct mbuf * m,int af,int hlen)517 in_gre_output(struct mbuf *m, int af, int hlen)
518 {
519 struct greip *gi;
520
521 gi = mtod(m, struct greip *);
522 switch (af) {
523 case AF_INET:
524 /*
525 * gre_transmit() has used M_PREPEND() that doesn't guarantee
526 * m_data is contiguous more than hlen bytes. Use m_copydata()
527 * here to avoid m_pullup().
528 */
529 m_copydata(m, hlen + offsetof(struct ip, ip_tos),
530 sizeof(u_char), &gi->gi_ip.ip_tos);
531 m_copydata(m, hlen + offsetof(struct ip, ip_id),
532 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id);
533 break;
534 #ifdef INET6
535 case AF_INET6:
536 gi->gi_ip.ip_tos = 0; /* XXX */
537 ip_fillid(&gi->gi_ip);
538 break;
539 #endif
540 }
541 gi->gi_ip.ip_ttl = V_ip_gre_ttl;
542 gi->gi_ip.ip_len = htons(m->m_pkthdr.len);
543 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL));
544 }
545
546 static const struct srcaddrtab *ipv4_srcaddrtab = NULL;
547 static const struct encaptab *ecookie = NULL;
548 static const struct encap_config ipv4_encap_cfg = {
549 .proto = IPPROTO_GRE,
550 .min_length = sizeof(struct greip) + sizeof(struct ip),
551 .exact_match = ENCAP_DRV_LOOKUP,
552 .lookup = in_gre_lookup,
553 .input = gre_input
554 };
555
556 void
in_gre_init(void)557 in_gre_init(void)
558 {
559
560 if (!IS_DEFAULT_VNET(curvnet))
561 return;
562 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr,
563 NULL, M_WAITOK);
564 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
565 }
566
567 void
in_gre_uninit(void)568 in_gre_uninit(void)
569 {
570
571 if (IS_DEFAULT_VNET(curvnet)) {
572 ip_encap_detach(ecookie);
573 ip_encap_unregister_srcaddr(ipv4_srcaddrtab);
574 }
575 if (V_ipv4_hashtbl != NULL) {
576 gre_hashdestroy(V_ipv4_hashtbl);
577 V_ipv4_hashtbl = NULL;
578 GRE_WAIT();
579 gre_hashdestroy(V_ipv4_srchashtbl);
580 gre_hashdestroy((struct gre_list *)V_ipv4_sockets);
581 }
582 }
583