1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
33 */
34
35 #include <sys/cdefs.h>
36 #include "opt_inet.h"
37 #include "opt_inet6.h"
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/jail.h>
42 #include <sys/socket.h>
43 #include <sys/sockio.h>
44 #include <sys/mbuf.h>
45 #include <sys/errno.h>
46 #include <sys/kernel.h>
47 #include <sys/syslog.h>
48 #include <sys/sysctl.h>
49 #include <sys/malloc.h>
50 #include <sys/proc.h>
51
52 #include <net/ethernet.h>
53 #include <net/if.h>
54 #include <net/if_var.h>
55 #include <net/if_private.h>
56 #include <net/route.h>
57 #include <net/vnet.h>
58
59 #include <netinet/in.h>
60 #include <netinet/in_systm.h>
61 #ifdef INET
62 #include <netinet/ip.h>
63 #include <netinet/ip_ecn.h>
64 #endif
65 #include <netinet/ip_encap.h>
66 #include <netinet/ip6.h>
67 #include <netinet6/ip6_var.h>
68 #include <netinet6/in6_var.h>
69 #include <netinet6/scope6_var.h>
70 #include <netinet6/ip6_ecn.h>
71 #include <netinet6/in6_fib.h>
72
73 #include <net/if_gif.h>
74
75 #define GIF_HLIM 30
76 VNET_DEFINE_STATIC(int, ip6_gif_hlim) = GIF_HLIM;
77 #define V_ip6_gif_hlim VNET(ip6_gif_hlim)
78
79 SYSCTL_DECL(_net_inet6_ip6);
80 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim,
81 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_gif_hlim), 0,
82 "Default hop limit for encapsulated packets");
83
84 /*
85 * We keep interfaces in a hash table using src+dst as key.
86 * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list.
87 */
88 VNET_DEFINE_STATIC(struct gif_list *, ipv6_hashtbl) = NULL;
89 VNET_DEFINE_STATIC(struct gif_list *, ipv6_srchashtbl) = NULL;
90 VNET_DEFINE_STATIC(struct gif_list, ipv6_list) = CK_LIST_HEAD_INITIALIZER();
91 #define V_ipv6_hashtbl VNET(ipv6_hashtbl)
92 #define V_ipv6_srchashtbl VNET(ipv6_srchashtbl)
93 #define V_ipv6_list VNET(ipv6_list)
94
95 #define GIF_HASH(src, dst) (V_ipv6_hashtbl[\
96 in6_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)])
97 #define GIF_SRCHASH(src) (V_ipv6_srchashtbl[\
98 fnv_32_buf((src), sizeof(*src), FNV1_32_INIT) & (GIF_HASH_SIZE - 1)])
99 #define GIF_HASH_SC(sc) GIF_HASH(&(sc)->gif_ip6hdr->ip6_src,\
100 &(sc)->gif_ip6hdr->ip6_dst)
101 static uint32_t
in6_gif_hashval(const struct in6_addr * src,const struct in6_addr * dst)102 in6_gif_hashval(const struct in6_addr *src, const struct in6_addr *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 int
in6_gif_checkdup(const struct gif_softc * sc,const struct in6_addr * src,const struct in6_addr * dst)111 in6_gif_checkdup(const struct gif_softc *sc, const struct in6_addr *src,
112 const struct in6_addr *dst)
113 {
114 struct gif_softc *tmp;
115
116 if (sc->gif_family == AF_INET6 &&
117 IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, src) &&
118 IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, dst))
119 return (EEXIST);
120
121 CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) {
122 if (tmp == sc)
123 continue;
124 if (IN6_ARE_ADDR_EQUAL(&tmp->gif_ip6hdr->ip6_src, src) &&
125 IN6_ARE_ADDR_EQUAL(&tmp->gif_ip6hdr->ip6_dst, dst))
126 return (EADDRNOTAVAIL);
127 }
128 return (0);
129 }
130
131 /*
132 * Check that ingress address belongs to local host.
133 */
134 static void
in6_gif_set_running(struct gif_softc * sc)135 in6_gif_set_running(struct gif_softc *sc)
136 {
137
138 if (in6_localip(&sc->gif_ip6hdr->ip6_src))
139 GIF2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
140 else
141 GIF2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
142 }
143
144 /*
145 * ifaddr_event handler.
146 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
147 * source address spoofing.
148 */
149 static void
in6_gif_srcaddr(void * arg __unused,const struct sockaddr * sa,int event)150 in6_gif_srcaddr(void *arg __unused, const struct sockaddr *sa, int event)
151 {
152 const struct sockaddr_in6 *sin;
153 struct gif_softc *sc;
154
155 /* Check that VNET is ready */
156 if (V_ipv6_hashtbl == NULL)
157 return;
158
159 NET_EPOCH_ASSERT();
160 sin = (const struct sockaddr_in6 *)sa;
161 CK_LIST_FOREACH(sc, &GIF_SRCHASH(&sin->sin6_addr), srchash) {
162 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
163 &sin->sin6_addr) == 0)
164 continue;
165 in6_gif_set_running(sc);
166 }
167 }
168
169 static void
in6_gif_attach(struct gif_softc * sc)170 in6_gif_attach(struct gif_softc *sc)
171 {
172
173 if (sc->gif_options & GIF_IGNORE_SOURCE)
174 CK_LIST_INSERT_HEAD(&V_ipv6_list, sc, chain);
175 else
176 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain);
177
178 CK_LIST_INSERT_HEAD(&GIF_SRCHASH(&sc->gif_ip6hdr->ip6_src),
179 sc, srchash);
180 }
181
182 int
in6_gif_setopts(struct gif_softc * sc,u_int options)183 in6_gif_setopts(struct gif_softc *sc, u_int options)
184 {
185
186 /* NOTE: we are protected with gif_ioctl_sx lock */
187 MPASS(sc->gif_family == AF_INET6);
188 MPASS(sc->gif_options != options);
189
190 if ((options & GIF_IGNORE_SOURCE) !=
191 (sc->gif_options & GIF_IGNORE_SOURCE)) {
192 CK_LIST_REMOVE(sc, srchash);
193 CK_LIST_REMOVE(sc, chain);
194 sc->gif_options = options;
195 in6_gif_attach(sc);
196 }
197
198 if ((options & GIF_NOCLAMP) !=
199 (sc->gif_options & GIF_NOCLAMP)) {
200 sc->gif_options = options;
201 }
202 return (0);
203 }
204
205 int
in6_gif_ioctl(struct gif_softc * sc,u_long cmd,caddr_t data)206 in6_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
207 {
208 struct in6_ifreq *ifr = (struct in6_ifreq *)data;
209 struct sockaddr_in6 *dst, *src;
210 struct ip6_hdr *ip6;
211 int error;
212
213 /* NOTE: we are protected with gif_ioctl_sx lock */
214 error = EINVAL;
215 switch (cmd) {
216 case SIOCSIFPHYADDR_IN6:
217 src = &((struct in6_aliasreq *)data)->ifra_addr;
218 dst = &((struct in6_aliasreq *)data)->ifra_dstaddr;
219
220 /* sanity checks */
221 if (src->sin6_family != dst->sin6_family ||
222 src->sin6_family != AF_INET6 ||
223 src->sin6_len != dst->sin6_len ||
224 src->sin6_len != sizeof(*src))
225 break;
226 if (IN6_IS_ADDR_UNSPECIFIED(&src->sin6_addr) ||
227 IN6_IS_ADDR_UNSPECIFIED(&dst->sin6_addr)) {
228 error = EADDRNOTAVAIL;
229 break;
230 }
231 /*
232 * Check validity of the scope zone ID of the
233 * addresses, and convert it into the kernel
234 * internal form if necessary.
235 */
236 if ((error = sa6_embedscope(src, 0)) != 0 ||
237 (error = sa6_embedscope(dst, 0)) != 0)
238 break;
239
240 if (V_ipv6_hashtbl == NULL) {
241 V_ipv6_hashtbl = gif_hashinit();
242 V_ipv6_srchashtbl = gif_hashinit();
243 }
244 error = in6_gif_checkdup(sc, &src->sin6_addr,
245 &dst->sin6_addr);
246 if (error == EADDRNOTAVAIL)
247 break;
248 if (error == EEXIST) {
249 /* Addresses are the same. Just return. */
250 error = 0;
251 break;
252 }
253 ip6 = malloc(sizeof(*ip6), M_GIF, M_WAITOK | M_ZERO);
254 ip6->ip6_src = src->sin6_addr;
255 ip6->ip6_dst = dst->sin6_addr;
256 ip6->ip6_vfc = IPV6_VERSION;
257 if (sc->gif_family != 0) {
258 /* Detach existing tunnel first */
259 CK_LIST_REMOVE(sc, srchash);
260 CK_LIST_REMOVE(sc, chain);
261 GIF_WAIT();
262 free(sc->gif_hdr, M_GIF);
263 /* XXX: should we notify about link state change? */
264 }
265 sc->gif_family = AF_INET6;
266 sc->gif_ip6hdr = ip6;
267 in6_gif_attach(sc);
268 in6_gif_set_running(sc);
269 break;
270 case SIOCGIFPSRCADDR_IN6:
271 case SIOCGIFPDSTADDR_IN6:
272 if (sc->gif_family != AF_INET6) {
273 error = EADDRNOTAVAIL;
274 break;
275 }
276 src = (struct sockaddr_in6 *)&ifr->ifr_addr;
277 memset(src, 0, sizeof(*src));
278 src->sin6_family = AF_INET6;
279 src->sin6_len = sizeof(*src);
280 src->sin6_addr = (cmd == SIOCGIFPSRCADDR_IN6) ?
281 sc->gif_ip6hdr->ip6_src: sc->gif_ip6hdr->ip6_dst;
282 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
283 if (error == 0)
284 error = sa6_recoverscope(src);
285 if (error != 0)
286 memset(src, 0, sizeof(*src));
287 break;
288 }
289 return (error);
290 }
291
292 int
in6_gif_output(struct ifnet * ifp,struct mbuf * m,int proto,uint8_t ecn)293 in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
294 {
295 struct gif_softc *sc = ifp->if_softc;
296 struct ip6_hdr *ip6;
297 u_long mtu;
298
299 /* prepend new IP header */
300 NET_EPOCH_ASSERT();
301 M_PREPEND(m, sizeof(struct ip6_hdr), M_NOWAIT);
302 if (m == NULL)
303 return (ENOBUFS);
304
305 ip6 = mtod(m, struct ip6_hdr *);
306 MPASS(sc->gif_family == AF_INET6);
307 memcpy(ip6, sc->gif_ip6hdr, sizeof(struct ip6_hdr));
308
309 ip6->ip6_flow |= htonl((uint32_t)ecn << 20);
310 ip6->ip6_nxt = proto;
311 ip6->ip6_hlim = V_ip6_gif_hlim;
312 /*
313 * Enforce fragmentation to minimum MTU, even if the interface MTU
314 * is larger, to avoid path MTU discovery when NOCLAMP is not
315 * set (default). IPv6 does not allow fragmentation on intermediate
316 * router nodes, so it is too painful to ask for resend of inner
317 * packet, to achieve path MTU discovery for encapsulated packets.
318 */
319 mtu = ((sc->gif_options & GIF_NOCLAMP) == 0) ? IPV6_MINMTU : 0;
320
321 return (ip6_output(m, 0, NULL, mtu, 0, NULL, NULL));
322 }
323
324 static int
in6_gif_input(struct mbuf * m,int off,int proto,void * arg)325 in6_gif_input(struct mbuf *m, int off, int proto, void *arg)
326 {
327 struct gif_softc *sc = arg;
328 struct ifnet *gifp;
329 struct ip6_hdr *ip6;
330 uint8_t ecn;
331
332 NET_EPOCH_ASSERT();
333 if (sc == NULL) {
334 m_freem(m);
335 IP6STAT_INC(ip6s_nogif);
336 return (IPPROTO_DONE);
337 }
338 gifp = GIF2IFP(sc);
339 if ((gifp->if_flags & IFF_UP) != 0) {
340 ip6 = mtod(m, struct ip6_hdr *);
341 ecn = IPV6_TRAFFIC_CLASS(ip6);
342 m_adj(m, off);
343 gif_input(m, gifp, proto, ecn);
344 } else {
345 m_freem(m);
346 IP6STAT_INC(ip6s_nogif);
347 }
348 return (IPPROTO_DONE);
349 }
350
351 static int
in6_gif_lookup(const struct mbuf * m,int off,int proto,void ** arg)352 in6_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
353 {
354 const struct ip6_hdr *ip6;
355 struct gif_softc *sc;
356 int ret;
357
358 if (V_ipv6_hashtbl == NULL)
359 return (0);
360
361 NET_EPOCH_ASSERT();
362 /*
363 * NOTE: it is safe to iterate without any locking here, because softc
364 * can be reclaimed only when we are not within net_epoch_preempt
365 * section, but ip_encap lookup+input are executed in epoch section.
366 */
367 ip6 = mtod(m, const struct ip6_hdr *);
368 ret = 0;
369 CK_LIST_FOREACH(sc, &GIF_HASH(&ip6->ip6_dst, &ip6->ip6_src), chain) {
370 /*
371 * This is an inbound packet, its ip6_dst is source address
372 * in softc.
373 */
374 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
375 &ip6->ip6_dst) &&
376 IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst,
377 &ip6->ip6_src)) {
378 ret = ENCAP_DRV_LOOKUP;
379 goto done;
380 }
381 }
382 /*
383 * No exact match.
384 * Check the list of interfaces with GIF_IGNORE_SOURCE flag.
385 */
386 CK_LIST_FOREACH(sc, &V_ipv6_list, chain) {
387 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
388 &ip6->ip6_dst)) {
389 ret = 128 + 8; /* src + proto */
390 goto done;
391 }
392 }
393 return (0);
394 done:
395 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
396 return (0);
397 /* ingress filters on outer source */
398 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
399 if (fib6_check_urpf(sc->gif_fibnum, &ip6->ip6_src,
400 ntohs(in6_getscope(&ip6->ip6_src)), NHR_NONE,
401 m->m_pkthdr.rcvif) == 0)
402 return (0);
403 }
404 *arg = sc;
405 return (ret);
406 }
407
408 static const struct srcaddrtab *ipv6_srcaddrtab;
409 static struct {
410 const struct encap_config encap;
411 const struct encaptab *cookie;
412 } ipv6_encap_cfg[] = {
413 #ifdef INET
414 {
415 .encap = {
416 .proto = IPPROTO_IPV4,
417 .min_length = sizeof(struct ip6_hdr) +
418 sizeof(struct ip),
419 .exact_match = ENCAP_DRV_LOOKUP,
420 .lookup = in6_gif_lookup,
421 .input = in6_gif_input
422 },
423 },
424 #endif
425 {
426 .encap = {
427 .proto = IPPROTO_IPV6,
428 .min_length = 2 * sizeof(struct ip6_hdr),
429 .exact_match = ENCAP_DRV_LOOKUP,
430 .lookup = in6_gif_lookup,
431 .input = in6_gif_input
432 },
433 },
434 {
435 .encap = {
436 .proto = IPPROTO_ETHERIP,
437 .min_length = sizeof(struct ip6_hdr) +
438 sizeof(struct etherip_header) +
439 sizeof(struct ether_header),
440 .exact_match = ENCAP_DRV_LOOKUP,
441 .lookup = in6_gif_lookup,
442 .input = in6_gif_input
443 },
444 }
445 };
446
447 void
in6_gif_init(void)448 in6_gif_init(void)
449 {
450 int i;
451
452 if (!IS_DEFAULT_VNET(curvnet))
453 return;
454
455 ipv6_srcaddrtab = ip6_encap_register_srcaddr(in6_gif_srcaddr,
456 NULL, M_WAITOK);
457 for (i = 0; i < nitems(ipv6_encap_cfg); i++)
458 ipv6_encap_cfg[i].cookie = ip6_encap_attach(
459 &ipv6_encap_cfg[i].encap, NULL, M_WAITOK);
460 }
461
462 void
in6_gif_uninit(void)463 in6_gif_uninit(void)
464 {
465 int i;
466
467 if (IS_DEFAULT_VNET(curvnet)) {
468 for (i = 0; i < nitems(ipv6_encap_cfg); i++)
469 ip6_encap_detach(ipv6_encap_cfg[i].cookie);
470 ip6_encap_unregister_srcaddr(ipv6_srcaddrtab);
471 }
472 if (V_ipv6_hashtbl != NULL) {
473 gif_hashdestroy(V_ipv6_hashtbl);
474 V_ipv6_hashtbl = NULL;
475 GIF_WAIT();
476 gif_hashdestroy(V_ipv6_srchashtbl);
477 }
478 }
479