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 return (0);
198 }
199
200 int
in6_gif_ioctl(struct gif_softc * sc,u_long cmd,caddr_t data)201 in6_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
202 {
203 struct in6_ifreq *ifr = (struct in6_ifreq *)data;
204 struct sockaddr_in6 *dst, *src;
205 struct ip6_hdr *ip6;
206 int error;
207
208 /* NOTE: we are protected with gif_ioctl_sx lock */
209 error = EINVAL;
210 switch (cmd) {
211 case SIOCSIFPHYADDR_IN6:
212 src = &((struct in6_aliasreq *)data)->ifra_addr;
213 dst = &((struct in6_aliasreq *)data)->ifra_dstaddr;
214
215 /* sanity checks */
216 if (src->sin6_family != dst->sin6_family ||
217 src->sin6_family != AF_INET6 ||
218 src->sin6_len != dst->sin6_len ||
219 src->sin6_len != sizeof(*src))
220 break;
221 if (IN6_IS_ADDR_UNSPECIFIED(&src->sin6_addr) ||
222 IN6_IS_ADDR_UNSPECIFIED(&dst->sin6_addr)) {
223 error = EADDRNOTAVAIL;
224 break;
225 }
226 /*
227 * Check validity of the scope zone ID of the
228 * addresses, and convert it into the kernel
229 * internal form if necessary.
230 */
231 if ((error = sa6_embedscope(src, 0)) != 0 ||
232 (error = sa6_embedscope(dst, 0)) != 0)
233 break;
234
235 if (V_ipv6_hashtbl == NULL) {
236 V_ipv6_hashtbl = gif_hashinit();
237 V_ipv6_srchashtbl = gif_hashinit();
238 }
239 error = in6_gif_checkdup(sc, &src->sin6_addr,
240 &dst->sin6_addr);
241 if (error == EADDRNOTAVAIL)
242 break;
243 if (error == EEXIST) {
244 /* Addresses are the same. Just return. */
245 error = 0;
246 break;
247 }
248 ip6 = malloc(sizeof(*ip6), M_GIF, M_WAITOK | M_ZERO);
249 ip6->ip6_src = src->sin6_addr;
250 ip6->ip6_dst = dst->sin6_addr;
251 ip6->ip6_vfc = IPV6_VERSION;
252 if (sc->gif_family != 0) {
253 /* Detach existing tunnel first */
254 CK_LIST_REMOVE(sc, srchash);
255 CK_LIST_REMOVE(sc, chain);
256 GIF_WAIT();
257 free(sc->gif_hdr, M_GIF);
258 /* XXX: should we notify about link state change? */
259 }
260 sc->gif_family = AF_INET6;
261 sc->gif_ip6hdr = ip6;
262 in6_gif_attach(sc);
263 in6_gif_set_running(sc);
264 break;
265 case SIOCGIFPSRCADDR_IN6:
266 case SIOCGIFPDSTADDR_IN6:
267 if (sc->gif_family != AF_INET6) {
268 error = EADDRNOTAVAIL;
269 break;
270 }
271 src = (struct sockaddr_in6 *)&ifr->ifr_addr;
272 memset(src, 0, sizeof(*src));
273 src->sin6_family = AF_INET6;
274 src->sin6_len = sizeof(*src);
275 src->sin6_addr = (cmd == SIOCGIFPSRCADDR_IN6) ?
276 sc->gif_ip6hdr->ip6_src: sc->gif_ip6hdr->ip6_dst;
277 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
278 if (error == 0)
279 error = sa6_recoverscope(src);
280 if (error != 0)
281 memset(src, 0, sizeof(*src));
282 break;
283 }
284 return (error);
285 }
286
287 int
in6_gif_output(struct ifnet * ifp,struct mbuf * m,int proto,uint8_t ecn)288 in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
289 {
290 struct gif_softc *sc = ifp->if_softc;
291 struct ip6_hdr *ip6;
292
293 /* prepend new IP header */
294 NET_EPOCH_ASSERT();
295 M_PREPEND(m, sizeof(struct ip6_hdr), M_NOWAIT);
296 if (m == NULL)
297 return (ENOBUFS);
298
299 ip6 = mtod(m, struct ip6_hdr *);
300 MPASS(sc->gif_family == AF_INET6);
301 memcpy(ip6, sc->gif_ip6hdr, sizeof(struct ip6_hdr));
302
303 ip6->ip6_flow |= htonl((uint32_t)ecn << 20);
304 ip6->ip6_nxt = proto;
305 ip6->ip6_hlim = V_ip6_gif_hlim;
306 /*
307 * force fragmentation to minimum MTU, to avoid path MTU discovery.
308 * it is too painful to ask for resend of inner packet, to achieve
309 * path MTU discovery for encapsulated packets.
310 */
311 return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
312 }
313
314 static int
in6_gif_input(struct mbuf * m,int off,int proto,void * arg)315 in6_gif_input(struct mbuf *m, int off, int proto, void *arg)
316 {
317 struct gif_softc *sc = arg;
318 struct ifnet *gifp;
319 struct ip6_hdr *ip6;
320 uint8_t ecn;
321
322 NET_EPOCH_ASSERT();
323 if (sc == NULL) {
324 m_freem(m);
325 IP6STAT_INC(ip6s_nogif);
326 return (IPPROTO_DONE);
327 }
328 gifp = GIF2IFP(sc);
329 if ((gifp->if_flags & IFF_UP) != 0) {
330 ip6 = mtod(m, struct ip6_hdr *);
331 ecn = IPV6_TRAFFIC_CLASS(ip6);
332 m_adj(m, off);
333 gif_input(m, gifp, proto, ecn);
334 } else {
335 m_freem(m);
336 IP6STAT_INC(ip6s_nogif);
337 }
338 return (IPPROTO_DONE);
339 }
340
341 static int
in6_gif_lookup(const struct mbuf * m,int off,int proto,void ** arg)342 in6_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
343 {
344 const struct ip6_hdr *ip6;
345 struct gif_softc *sc;
346 int ret;
347
348 if (V_ipv6_hashtbl == NULL)
349 return (0);
350
351 NET_EPOCH_ASSERT();
352 /*
353 * NOTE: it is safe to iterate without any locking here, because softc
354 * can be reclaimed only when we are not within net_epoch_preempt
355 * section, but ip_encap lookup+input are executed in epoch section.
356 */
357 ip6 = mtod(m, const struct ip6_hdr *);
358 ret = 0;
359 CK_LIST_FOREACH(sc, &GIF_HASH(&ip6->ip6_dst, &ip6->ip6_src), chain) {
360 /*
361 * This is an inbound packet, its ip6_dst is source address
362 * in softc.
363 */
364 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
365 &ip6->ip6_dst) &&
366 IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst,
367 &ip6->ip6_src)) {
368 ret = ENCAP_DRV_LOOKUP;
369 goto done;
370 }
371 }
372 /*
373 * No exact match.
374 * Check the list of interfaces with GIF_IGNORE_SOURCE flag.
375 */
376 CK_LIST_FOREACH(sc, &V_ipv6_list, chain) {
377 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
378 &ip6->ip6_dst)) {
379 ret = 128 + 8; /* src + proto */
380 goto done;
381 }
382 }
383 return (0);
384 done:
385 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
386 return (0);
387 /* ingress filters on outer source */
388 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
389 if (fib6_check_urpf(sc->gif_fibnum, &ip6->ip6_src,
390 ntohs(in6_getscope(&ip6->ip6_src)), NHR_NONE,
391 m->m_pkthdr.rcvif) == 0)
392 return (0);
393 }
394 *arg = sc;
395 return (ret);
396 }
397
398 static const struct srcaddrtab *ipv6_srcaddrtab;
399 static struct {
400 const struct encap_config encap;
401 const struct encaptab *cookie;
402 } ipv6_encap_cfg[] = {
403 #ifdef INET
404 {
405 .encap = {
406 .proto = IPPROTO_IPV4,
407 .min_length = sizeof(struct ip6_hdr) +
408 sizeof(struct ip),
409 .exact_match = ENCAP_DRV_LOOKUP,
410 .lookup = in6_gif_lookup,
411 .input = in6_gif_input
412 },
413 },
414 #endif
415 {
416 .encap = {
417 .proto = IPPROTO_IPV6,
418 .min_length = 2 * sizeof(struct ip6_hdr),
419 .exact_match = ENCAP_DRV_LOOKUP,
420 .lookup = in6_gif_lookup,
421 .input = in6_gif_input
422 },
423 },
424 {
425 .encap = {
426 .proto = IPPROTO_ETHERIP,
427 .min_length = sizeof(struct ip6_hdr) +
428 sizeof(struct etherip_header) +
429 sizeof(struct ether_header),
430 .exact_match = ENCAP_DRV_LOOKUP,
431 .lookup = in6_gif_lookup,
432 .input = in6_gif_input
433 },
434 }
435 };
436
437 void
in6_gif_init(void)438 in6_gif_init(void)
439 {
440 int i;
441
442 if (!IS_DEFAULT_VNET(curvnet))
443 return;
444
445 ipv6_srcaddrtab = ip6_encap_register_srcaddr(in6_gif_srcaddr,
446 NULL, M_WAITOK);
447 for (i = 0; i < nitems(ipv6_encap_cfg); i++)
448 ipv6_encap_cfg[i].cookie = ip6_encap_attach(
449 &ipv6_encap_cfg[i].encap, NULL, M_WAITOK);
450 }
451
452 void
in6_gif_uninit(void)453 in6_gif_uninit(void)
454 {
455 int i;
456
457 if (IS_DEFAULT_VNET(curvnet)) {
458 for (i = 0; i < nitems(ipv6_encap_cfg); i++)
459 ip6_encap_detach(ipv6_encap_cfg[i].cookie);
460 ip6_encap_unregister_srcaddr(ipv6_srcaddrtab);
461 }
462 if (V_ipv6_hashtbl != NULL) {
463 gif_hashdestroy(V_ipv6_hashtbl);
464 V_ipv6_hashtbl = NULL;
465 GIF_WAIT();
466 gif_hashdestroy(V_ipv6_srchashtbl);
467 }
468 }
469