FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_gre.c
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 <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 __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
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*
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
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
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
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
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 bool
223 in_gre_udp_input(struct mbuf *m, int off, struct inpcb *inp,
224 const struct sockaddr *sa, void *ctx)
225 {
226 struct gre_socket *gs;
227 struct gre_softc *sc;
228 in_addr_t dst;
229
230 NET_EPOCH_ASSERT();
231
232 gs = (struct gre_socket *)ctx;
233 dst = ((const struct sockaddr_in *)sa)->sin_addr.s_addr;
234 CK_LIST_FOREACH(sc, &gs->list, chain) {
235 if (sc->gre_oip.ip_dst.s_addr == dst)
236 break;
237 }
238 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){
239 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc);
240 return (true);
241 }
242 m_freem(m);
243
244 return (true);
245 }
246
247 static int
248 in_gre_setup_socket(struct gre_softc *sc)
249 {
250 struct sockopt sopt;
251 struct sockaddr_in sin;
252 struct in_gre_socket *s;
253 struct gre_socket *gs;
254 in_addr_t addr;
255 int error, value;
256
257 /*
258 * NOTE: we are protected with gre_ioctl_sx lock.
259 *
260 * First check that socket is already configured.
261 * If so, check that source address was not changed.
262 * If address is different, check that there are no other tunnels
263 * and close socket.
264 */
265 addr = sc->gre_oip.ip_src.s_addr;
266 gs = sc->gre_so;
267 if (gs != NULL) {
268 s = __containerof(gs, struct in_gre_socket, base);
269 if (s->addr != addr) {
270 if (CK_LIST_EMPTY(&gs->list)) {
271 CK_LIST_REMOVE(gs, chain);
272 soclose(gs->so);
273 NET_EPOCH_CALL(gre_sofree, &gs->epoch_ctx);
274 }
275 gs = sc->gre_so = NULL;
276 }
277 }
278
279 if (gs == NULL) {
280 /*
281 * Check that socket for given address is already
282 * configured.
283 */
284 gs = in_gre_lookup_socket(addr);
285 if (gs == NULL) {
286 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO);
287 s->addr = addr;
288 gs = &s->base;
289
290 error = socreate(sc->gre_family, &gs->so,
291 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred,
292 curthread);
293 if (error != 0) {
294 if_printf(GRE2IFP(sc),
295 "cannot create socket: %d\n", error);
296 free(s, M_GRE);
297 return (error);
298 }
299
300 error = udp_set_kernel_tunneling(gs->so,
301 in_gre_udp_input, NULL, gs);
302 if (error != 0) {
303 if_printf(GRE2IFP(sc),
304 "cannot set UDP tunneling: %d\n", error);
305 goto fail;
306 }
307
308 memset(&sopt, 0, sizeof(sopt));
309 sopt.sopt_dir = SOPT_SET;
310 sopt.sopt_level = IPPROTO_IP;
311 sopt.sopt_name = IP_BINDANY;
312 sopt.sopt_val = &value;
313 sopt.sopt_valsize = sizeof(value);
314 value = 1;
315 error = sosetopt(gs->so, &sopt);
316 if (error != 0) {
317 if_printf(GRE2IFP(sc),
318 "cannot set IP_BINDANY opt: %d\n", error);
319 goto fail;
320 }
321
322 memset(&sin, 0, sizeof(sin));
323 sin.sin_family = AF_INET;
324 sin.sin_len = sizeof(sin);
325 sin.sin_addr.s_addr = addr;
326 sin.sin_port = htons(GRE_UDPPORT);
327 error = sobind(gs->so, (struct sockaddr *)&sin,
328 curthread);
329 if (error != 0) {
330 if_printf(GRE2IFP(sc),
331 "cannot bind socket: %d\n", error);
332 goto fail;
333 }
334 /* Add socket to the chain */
335 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain);
336 }
337 }
338
339 /* Add softc to the socket's list */
340 CK_LIST_INSERT_HEAD(&gs->list, sc, chain);
341 sc->gre_so = gs;
342 return (0);
343 fail:
344 soclose(gs->so);
345 free(s, M_GRE);
346 return (error);
347 }
348
349 static int
350 in_gre_attach(struct gre_softc *sc)
351 {
352 struct epoch_tracker et;
353 struct grehdr *gh;
354 int error;
355
356 if (sc->gre_options & GRE_UDPENCAP) {
357 sc->gre_csumflags = CSUM_UDP;
358 sc->gre_hlen = sizeof(struct greudp);
359 sc->gre_oip.ip_p = IPPROTO_UDP;
360 gh = &sc->gre_udphdr->gi_gre;
361 gre_update_udphdr(sc, &sc->gre_udp,
362 in_pseudo(sc->gre_oip.ip_src.s_addr,
363 sc->gre_oip.ip_dst.s_addr, 0));
364 } else {
365 sc->gre_hlen = sizeof(struct greip);
366 sc->gre_oip.ip_p = IPPROTO_GRE;
367 gh = &sc->gre_iphdr->gi_gre;
368 }
369 sc->gre_oip.ip_v = IPVERSION;
370 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2;
371 gre_update_hdr(sc, gh);
372
373 /*
374 * If we return error, this means that sc is not linked,
375 * and caller should reset gre_family and free(sc->gre_hdr).
376 */
377 if (sc->gre_options & GRE_UDPENCAP) {
378 error = in_gre_setup_socket(sc);
379 if (error != 0)
380 return (error);
381 } else
382 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain);
383 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr),
384 sc, srchash);
385
386 /* Set IFF_DRV_RUNNING if interface is ready */
387 NET_EPOCH_ENTER(et);
388 in_gre_set_running(sc);
389 NET_EPOCH_EXIT(et);
390 return (0);
391 }
392
393 int
394 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value)
395 {
396 int error;
397
398 /* NOTE: we are protected with gre_ioctl_sx lock */
399 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT);
400 MPASS(sc->gre_family == AF_INET);
401
402 /*
403 * If we are going to change encapsulation protocol, do check
404 * for duplicate tunnels. Return EEXIST here to do not confuse
405 * user.
406 */
407 if (cmd == GRESOPTS &&
408 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) &&
409 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr,
410 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL)
411 return (EEXIST);
412
413 CK_LIST_REMOVE(sc, chain);
414 CK_LIST_REMOVE(sc, srchash);
415 GRE_WAIT();
416 switch (cmd) {
417 case GRESKEY:
418 sc->gre_key = value;
419 break;
420 case GRESOPTS:
421 sc->gre_options = value;
422 break;
423 case GRESPORT:
424 sc->gre_port = value;
425 break;
426 }
427 error = in_gre_attach(sc);
428 if (error != 0) {
429 sc->gre_family = 0;
430 free(sc->gre_hdr, M_GRE);
431 }
432 return (error);
433 }
434
435 int
436 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data)
437 {
438 struct ifreq *ifr = (struct ifreq *)data;
439 struct sockaddr_in *dst, *src;
440 struct ip *ip;
441 int error;
442
443 /* NOTE: we are protected with gre_ioctl_sx lock */
444 error = EINVAL;
445 switch (cmd) {
446 case SIOCSIFPHYADDR:
447 src = &((struct in_aliasreq *)data)->ifra_addr;
448 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
449
450 /* sanity checks */
451 if (src->sin_family != dst->sin_family ||
452 src->sin_family != AF_INET ||
453 src->sin_len != dst->sin_len ||
454 src->sin_len != sizeof(*src))
455 break;
456 if (src->sin_addr.s_addr == INADDR_ANY ||
457 dst->sin_addr.s_addr == INADDR_ANY) {
458 error = EADDRNOTAVAIL;
459 break;
460 }
461 if (V_ipv4_hashtbl == NULL) {
462 V_ipv4_hashtbl = gre_hashinit();
463 V_ipv4_srchashtbl = gre_hashinit();
464 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit();
465 }
466 error = in_gre_checkdup(sc, src->sin_addr.s_addr,
467 dst->sin_addr.s_addr, sc->gre_options);
468 if (error == EADDRNOTAVAIL)
469 break;
470 if (error == EEXIST) {
471 /* Addresses are the same. Just return. */
472 error = 0;
473 break;
474 }
475 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t),
476 M_GRE, M_WAITOK | M_ZERO);
477 ip->ip_src.s_addr = src->sin_addr.s_addr;
478 ip->ip_dst.s_addr = dst->sin_addr.s_addr;
479 if (sc->gre_family != 0) {
480 /* Detach existing tunnel first */
481 CK_LIST_REMOVE(sc, chain);
482 CK_LIST_REMOVE(sc, srchash);
483 GRE_WAIT();
484 free(sc->gre_hdr, M_GRE);
485 /* XXX: should we notify about link state change? */
486 }
487 sc->gre_family = AF_INET;
488 sc->gre_hdr = ip;
489 sc->gre_oseq = 0;
490 sc->gre_iseq = UINT32_MAX;
491 error = in_gre_attach(sc);
492 if (error != 0) {
493 sc->gre_family = 0;
494 free(sc->gre_hdr, M_GRE);
495 }
496 break;
497 case SIOCGIFPSRCADDR:
498 case SIOCGIFPDSTADDR:
499 if (sc->gre_family != AF_INET) {
500 error = EADDRNOTAVAIL;
501 break;
502 }
503 src = (struct sockaddr_in *)&ifr->ifr_addr;
504 memset(src, 0, sizeof(*src));
505 src->sin_family = AF_INET;
506 src->sin_len = sizeof(*src);
507 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
508 sc->gre_oip.ip_src: sc->gre_oip.ip_dst;
509 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
510 if (error != 0)
511 memset(src, 0, sizeof(*src));
512 break;
513 }
514 return (error);
515 }
516
517 int
518 in_gre_output(struct mbuf *m, int af, int hlen)
519 {
520 struct greip *gi;
521
522 gi = mtod(m, struct greip *);
523 switch (af) {
524 case AF_INET:
525 /*
526 * gre_transmit() has used M_PREPEND() that doesn't guarantee
527 * m_data is contiguous more than hlen bytes. Use m_copydata()
528 * here to avoid m_pullup().
529 */
530 m_copydata(m, hlen + offsetof(struct ip, ip_tos),
531 sizeof(u_char), &gi->gi_ip.ip_tos);
532 m_copydata(m, hlen + offsetof(struct ip, ip_id),
533 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id);
534 break;
535 #ifdef INET6
536 case AF_INET6:
537 gi->gi_ip.ip_tos = 0; /* XXX */
538 ip_fillid(&gi->gi_ip);
539 break;
540 #endif
541 }
542 gi->gi_ip.ip_ttl = V_ip_gre_ttl;
543 gi->gi_ip.ip_len = htons(m->m_pkthdr.len);
544 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL));
545 }
546
547 static const struct srcaddrtab *ipv4_srcaddrtab = NULL;
548 static const struct encaptab *ecookie = NULL;
549 static const struct encap_config ipv4_encap_cfg = {
550 .proto = IPPROTO_GRE,
551 .min_length = sizeof(struct greip) + sizeof(struct ip),
552 .exact_match = ENCAP_DRV_LOOKUP,
553 .lookup = in_gre_lookup,
554 .input = gre_input
555 };
556
557 void
558 in_gre_init(void)
559 {
560
561 if (!IS_DEFAULT_VNET(curvnet))
562 return;
563 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr,
564 NULL, M_WAITOK);
565 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
566 }
567
568 void
569 in_gre_uninit(void)
570 {
571
572 if (IS_DEFAULT_VNET(curvnet)) {
573 ip_encap_detach(ecookie);
574 ip_encap_unregister_srcaddr(ipv4_srcaddrtab);
575 }
576 if (V_ipv4_hashtbl != NULL) {
577 gre_hashdestroy(V_ipv4_hashtbl);
578 V_ipv4_hashtbl = NULL;
579 GRE_WAIT();
580 gre_hashdestroy(V_ipv4_srchashtbl);
581 gre_hashdestroy((struct gre_list *)V_ipv4_sockets);
582 }
583 }
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