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 "opt_inet.h"
38 #include "opt_inet6.h"
39
40 #include <sys/param.h>
41 #include <sys/jail.h>
42 #include <sys/systm.h>
43 #include <sys/socket.h>
44 #include <sys/socketvar.h>
45 #include <sys/sockio.h>
46 #include <sys/mbuf.h>
47 #include <sys/errno.h>
48 #include <sys/kernel.h>
49 #include <sys/sysctl.h>
50 #include <sys/malloc.h>
51 #include <sys/proc.h>
52
53 #include <net/if.h>
54 #include <net/if_var.h>
55 #include <net/if_private.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 bool
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 gre_socket *gs;
225 struct gre_softc *sc;
226 in_addr_t dst;
227
228 NET_EPOCH_ASSERT();
229
230 gs = (struct gre_socket *)ctx;
231 dst = ((const struct sockaddr_in *)sa)->sin_addr.s_addr;
232 CK_LIST_FOREACH(sc, &gs->list, chain) {
233 if (sc->gre_oip.ip_dst.s_addr == dst)
234 break;
235 }
236 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){
237 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc);
238 return (true);
239 }
240 m_freem(m);
241
242 return (true);
243 }
244
245 static int
in_gre_setup_socket(struct gre_softc * sc)246 in_gre_setup_socket(struct gre_softc *sc)
247 {
248 struct sockopt sopt;
249 struct sockaddr_in sin;
250 struct in_gre_socket *s;
251 struct gre_socket *gs;
252 in_addr_t addr;
253 int error, value;
254
255 /*
256 * NOTE: we are protected with gre_ioctl_sx lock.
257 *
258 * First check that socket is already configured.
259 * If so, check that source address was not changed.
260 * If address is different, check that there are no other tunnels
261 * and close socket.
262 */
263 addr = sc->gre_oip.ip_src.s_addr;
264 gs = sc->gre_so;
265 if (gs != NULL) {
266 s = __containerof(gs, struct in_gre_socket, base);
267 if (s->addr != addr) {
268 if (CK_LIST_EMPTY(&gs->list)) {
269 CK_LIST_REMOVE(gs, chain);
270 soclose(gs->so);
271 NET_EPOCH_CALL(gre_sofree, &gs->epoch_ctx);
272 }
273 gs = sc->gre_so = NULL;
274 }
275 }
276
277 if (gs == NULL) {
278 /*
279 * Check that socket for given address is already
280 * configured.
281 */
282 gs = in_gre_lookup_socket(addr);
283 if (gs == NULL) {
284 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO);
285 s->addr = addr;
286 gs = &s->base;
287
288 error = socreate(sc->gre_family, &gs->so,
289 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred,
290 curthread);
291 if (error != 0) {
292 if_printf(GRE2IFP(sc),
293 "cannot create socket: %d\n", error);
294 free(s, M_GRE);
295 return (error);
296 }
297
298 error = udp_set_kernel_tunneling(gs->so,
299 in_gre_udp_input, NULL, gs);
300 if (error != 0) {
301 if_printf(GRE2IFP(sc),
302 "cannot set UDP tunneling: %d\n", error);
303 goto fail;
304 }
305
306 memset(&sopt, 0, sizeof(sopt));
307 sopt.sopt_dir = SOPT_SET;
308 sopt.sopt_level = IPPROTO_IP;
309 sopt.sopt_name = IP_BINDANY;
310 sopt.sopt_val = &value;
311 sopt.sopt_valsize = sizeof(value);
312 value = 1;
313 error = sosetopt(gs->so, &sopt);
314 if (error != 0) {
315 if_printf(GRE2IFP(sc),
316 "cannot set IP_BINDANY opt: %d\n", error);
317 goto fail;
318 }
319
320 memset(&sin, 0, sizeof(sin));
321 sin.sin_family = AF_INET;
322 sin.sin_len = sizeof(sin);
323 sin.sin_addr.s_addr = addr;
324 sin.sin_port = htons(GRE_UDPPORT);
325 error = sobind(gs->so, (struct sockaddr *)&sin,
326 curthread);
327 if (error != 0) {
328 if_printf(GRE2IFP(sc),
329 "cannot bind socket: %d\n", error);
330 goto fail;
331 }
332 /* Add socket to the chain */
333 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain);
334 }
335 }
336
337 /* Add softc to the socket's list */
338 CK_LIST_INSERT_HEAD(&gs->list, sc, chain);
339 sc->gre_so = gs;
340 return (0);
341 fail:
342 soclose(gs->so);
343 free(s, M_GRE);
344 return (error);
345 }
346
347 static int
in_gre_attach(struct gre_softc * sc)348 in_gre_attach(struct gre_softc *sc)
349 {
350 struct epoch_tracker et;
351 struct grehdr *gh;
352 int error;
353
354 if (sc->gre_options & GRE_UDPENCAP) {
355 sc->gre_csumflags = CSUM_UDP;
356 sc->gre_hlen = sizeof(struct greudp);
357 sc->gre_oip.ip_p = IPPROTO_UDP;
358 gh = &sc->gre_udphdr->gi_gre;
359 gre_update_udphdr(sc, &sc->gre_udp,
360 in_pseudo(sc->gre_oip.ip_src.s_addr,
361 sc->gre_oip.ip_dst.s_addr, 0));
362 } else {
363 sc->gre_hlen = sizeof(struct greip);
364 sc->gre_oip.ip_p = IPPROTO_GRE;
365 gh = &sc->gre_iphdr->gi_gre;
366 }
367 sc->gre_oip.ip_v = IPVERSION;
368 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2;
369 gre_update_hdr(sc, gh);
370
371 /*
372 * If we return error, this means that sc is not linked,
373 * and caller should reset gre_family and free(sc->gre_hdr).
374 */
375 if (sc->gre_options & GRE_UDPENCAP) {
376 error = in_gre_setup_socket(sc);
377 if (error != 0)
378 return (error);
379 } else
380 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain);
381 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr),
382 sc, srchash);
383
384 /* Set IFF_DRV_RUNNING if interface is ready */
385 NET_EPOCH_ENTER(et);
386 in_gre_set_running(sc);
387 NET_EPOCH_EXIT(et);
388 return (0);
389 }
390
391 int
in_gre_setopts(struct gre_softc * sc,u_long cmd,uint32_t value)392 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value)
393 {
394 int error;
395
396 /* NOTE: we are protected with gre_ioctl_sx lock */
397 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT);
398 MPASS(sc->gre_family == AF_INET);
399
400 /*
401 * If we are going to change encapsulation protocol, do check
402 * for duplicate tunnels. Return EEXIST here to do not confuse
403 * user.
404 */
405 if (cmd == GRESOPTS &&
406 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) &&
407 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr,
408 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL)
409 return (EEXIST);
410
411 CK_LIST_REMOVE(sc, chain);
412 CK_LIST_REMOVE(sc, srchash);
413 GRE_WAIT();
414 switch (cmd) {
415 case GRESKEY:
416 sc->gre_key = value;
417 break;
418 case GRESOPTS:
419 sc->gre_options = value;
420 break;
421 case GRESPORT:
422 sc->gre_port = value;
423 break;
424 }
425 error = in_gre_attach(sc);
426 if (error != 0) {
427 sc->gre_family = 0;
428 free(sc->gre_hdr, M_GRE);
429 }
430 return (error);
431 }
432
433 int
in_gre_ioctl(struct gre_softc * sc,u_long cmd,caddr_t data)434 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data)
435 {
436 struct ifreq *ifr = (struct ifreq *)data;
437 struct sockaddr_in *dst, *src;
438 struct ip *ip;
439 int error;
440
441 /* NOTE: we are protected with gre_ioctl_sx lock */
442 error = EINVAL;
443 switch (cmd) {
444 case SIOCSIFPHYADDR:
445 src = &((struct in_aliasreq *)data)->ifra_addr;
446 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
447
448 /* sanity checks */
449 if (src->sin_family != dst->sin_family ||
450 src->sin_family != AF_INET ||
451 src->sin_len != dst->sin_len ||
452 src->sin_len != sizeof(*src))
453 break;
454 if (src->sin_addr.s_addr == INADDR_ANY ||
455 dst->sin_addr.s_addr == INADDR_ANY) {
456 error = EADDRNOTAVAIL;
457 break;
458 }
459 if (V_ipv4_hashtbl == NULL) {
460 V_ipv4_hashtbl = gre_hashinit();
461 V_ipv4_srchashtbl = gre_hashinit();
462 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit();
463 }
464 error = in_gre_checkdup(sc, src->sin_addr.s_addr,
465 dst->sin_addr.s_addr, sc->gre_options);
466 if (error == EADDRNOTAVAIL)
467 break;
468 if (error == EEXIST) {
469 /* Addresses are the same. Just return. */
470 error = 0;
471 break;
472 }
473 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t),
474 M_GRE, M_WAITOK | M_ZERO);
475 ip->ip_src.s_addr = src->sin_addr.s_addr;
476 ip->ip_dst.s_addr = dst->sin_addr.s_addr;
477 if (sc->gre_family != 0) {
478 /* Detach existing tunnel first */
479 CK_LIST_REMOVE(sc, chain);
480 CK_LIST_REMOVE(sc, srchash);
481 GRE_WAIT();
482 free(sc->gre_hdr, M_GRE);
483 /* XXX: should we notify about link state change? */
484 }
485 sc->gre_family = AF_INET;
486 sc->gre_hdr = ip;
487 sc->gre_oseq = 0;
488 sc->gre_iseq = UINT32_MAX;
489 error = in_gre_attach(sc);
490 if (error != 0) {
491 sc->gre_family = 0;
492 free(sc->gre_hdr, M_GRE);
493 }
494 break;
495 case SIOCGIFPSRCADDR:
496 case SIOCGIFPDSTADDR:
497 if (sc->gre_family != AF_INET) {
498 error = EADDRNOTAVAIL;
499 break;
500 }
501 src = (struct sockaddr_in *)&ifr->ifr_addr;
502 memset(src, 0, sizeof(*src));
503 src->sin_family = AF_INET;
504 src->sin_len = sizeof(*src);
505 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
506 sc->gre_oip.ip_src: sc->gre_oip.ip_dst;
507 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
508 if (error != 0)
509 memset(src, 0, sizeof(*src));
510 break;
511 }
512 return (error);
513 }
514
515 int
in_gre_output(struct mbuf * m,int af,int hlen)516 in_gre_output(struct mbuf *m, int af, int hlen)
517 {
518 struct greip *gi;
519
520 gi = mtod(m, struct greip *);
521 switch (af) {
522 case AF_INET:
523 /*
524 * gre_transmit() has used M_PREPEND() that doesn't guarantee
525 * m_data is contiguous more than hlen bytes. Use m_copydata()
526 * here to avoid m_pullup().
527 */
528 m_copydata(m, hlen + offsetof(struct ip, ip_tos),
529 sizeof(u_char), &gi->gi_ip.ip_tos);
530 m_copydata(m, hlen + offsetof(struct ip, ip_id),
531 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id);
532 break;
533 #ifdef INET6
534 case AF_INET6:
535 gi->gi_ip.ip_tos = 0; /* XXX */
536 ip_fillid(&gi->gi_ip, V_ip_random_id);
537 break;
538 #endif
539 }
540 gi->gi_ip.ip_ttl = V_ip_gre_ttl;
541 gi->gi_ip.ip_len = htons(m->m_pkthdr.len);
542 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL));
543 }
544
545 static const struct srcaddrtab *ipv4_srcaddrtab = NULL;
546 static const struct encaptab *ecookie = NULL;
547 static const struct encap_config ipv4_encap_cfg = {
548 .proto = IPPROTO_GRE,
549 .min_length = sizeof(struct greip) + sizeof(struct ip),
550 .exact_match = ENCAP_DRV_LOOKUP,
551 .lookup = in_gre_lookup,
552 .input = gre_input
553 };
554
555 void
in_gre_init(void)556 in_gre_init(void)
557 {
558
559 if (!IS_DEFAULT_VNET(curvnet))
560 return;
561 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr,
562 NULL, M_WAITOK);
563 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
564 }
565
566 void
in_gre_uninit(void)567 in_gre_uninit(void)
568 {
569
570 if (IS_DEFAULT_VNET(curvnet)) {
571 ip_encap_detach(ecookie);
572 ip_encap_unregister_srcaddr(ipv4_srcaddrtab);
573 }
574 if (V_ipv4_hashtbl != NULL) {
575 gre_hashdestroy(V_ipv4_hashtbl);
576 V_ipv4_hashtbl = NULL;
577 GRE_WAIT();
578 gre_hashdestroy(V_ipv4_srchashtbl);
579 gre_hashdestroy((struct gre_list *)V_ipv4_sockets);
580 }
581 }
582