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 __FBSDID("$FreeBSD: releng/12.0/sys/netinet6/in6_gif.c 337900 2018-08-16 09:19:06Z ae $");
37
38 #include "opt_inet.h"
39 #include "opt_inet6.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/jail.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
46 #include <sys/mbuf.h>
47 #include <sys/errno.h>
48 #include <sys/kernel.h>
49 #include <sys/syslog.h>
50 #include <sys/sysctl.h>
51 #include <sys/malloc.h>
52 #include <sys/proc.h>
53
54 #include <net/ethernet.h>
55 #include <net/if.h>
56 #include <net/if_var.h>
57 #include <net/route.h>
58 #include <net/vnet.h>
59
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #ifdef INET
63 #include <netinet/ip.h>
64 #include <netinet/ip_ecn.h>
65 #endif
66 #include <netinet/ip_encap.h>
67 #include <netinet/ip6.h>
68 #include <netinet6/ip6_var.h>
69 #include <netinet6/in6_var.h>
70 #include <netinet6/scope6_var.h>
71 #include <netinet6/ip6_ecn.h>
72 #include <netinet6/in6_fib.h>
73
74 #include <net/if_gif.h>
75
76 #define GIF_HLIM 30
77 VNET_DEFINE_STATIC(int, ip6_gif_hlim) = GIF_HLIM;
78 #define V_ip6_gif_hlim VNET(ip6_gif_hlim)
79
80 SYSCTL_DECL(_net_inet6_ip6);
81 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim,
82 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_gif_hlim), 0,
83 "Default hop limit for encapsulated packets");
84
85 /*
86 * We keep interfaces in a hash table using src+dst as key.
87 * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list.
88 */
89 VNET_DEFINE_STATIC(struct gif_list *, ipv6_hashtbl) = 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_list VNET(ipv6_list)
93
94 #define GIF_HASH(src, dst) (V_ipv6_hashtbl[\
95 in6_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)])
96 #define GIF_HASH_SC(sc) GIF_HASH(&(sc)->gif_ip6hdr->ip6_src,\
97 &(sc)->gif_ip6hdr->ip6_dst)
98 static uint32_t
99 in6_gif_hashval(const struct in6_addr *src, const struct in6_addr *dst)
100 {
101 uint32_t ret;
102
103 ret = fnv_32_buf(src, sizeof(*src), FNV1_32_INIT);
104 return (fnv_32_buf(dst, sizeof(*dst), ret));
105 }
106
107 static int
108 in6_gif_checkdup(const struct gif_softc *sc, const struct in6_addr *src,
109 const struct in6_addr *dst)
110 {
111 struct gif_softc *tmp;
112
113 if (sc->gif_family == AF_INET6 &&
114 IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, src) &&
115 IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, dst))
116 return (EEXIST);
117
118 CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) {
119 if (tmp == sc)
120 continue;
121 if (IN6_ARE_ADDR_EQUAL(&tmp->gif_ip6hdr->ip6_src, src) &&
122 IN6_ARE_ADDR_EQUAL(&tmp->gif_ip6hdr->ip6_dst, dst))
123 return (EADDRNOTAVAIL);
124 }
125 return (0);
126 }
127
128 static void
129 in6_gif_attach(struct gif_softc *sc)
130 {
131
132 if (sc->gif_options & GIF_IGNORE_SOURCE)
133 CK_LIST_INSERT_HEAD(&V_ipv6_list, sc, chain);
134 else
135 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain);
136 }
137
138 int
139 in6_gif_setopts(struct gif_softc *sc, u_int options)
140 {
141
142 /* NOTE: we are protected with gif_ioctl_sx lock */
143 MPASS(sc->gif_family == AF_INET6);
144 MPASS(sc->gif_options != options);
145
146 if ((options & GIF_IGNORE_SOURCE) !=
147 (sc->gif_options & GIF_IGNORE_SOURCE)) {
148 CK_LIST_REMOVE(sc, chain);
149 sc->gif_options = options;
150 in6_gif_attach(sc);
151 }
152 return (0);
153 }
154
155 int
156 in6_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
157 {
158 struct in6_ifreq *ifr = (struct in6_ifreq *)data;
159 struct sockaddr_in6 *dst, *src;
160 struct ip6_hdr *ip6;
161 int error;
162
163 /* NOTE: we are protected with gif_ioctl_sx lock */
164 error = EINVAL;
165 switch (cmd) {
166 case SIOCSIFPHYADDR_IN6:
167 src = &((struct in6_aliasreq *)data)->ifra_addr;
168 dst = &((struct in6_aliasreq *)data)->ifra_dstaddr;
169
170 /* sanity checks */
171 if (src->sin6_family != dst->sin6_family ||
172 src->sin6_family != AF_INET6 ||
173 src->sin6_len != dst->sin6_len ||
174 src->sin6_len != sizeof(*src))
175 break;
176 if (IN6_IS_ADDR_UNSPECIFIED(&src->sin6_addr) ||
177 IN6_IS_ADDR_UNSPECIFIED(&dst->sin6_addr)) {
178 error = EADDRNOTAVAIL;
179 break;
180 }
181 /*
182 * Check validity of the scope zone ID of the
183 * addresses, and convert it into the kernel
184 * internal form if necessary.
185 */
186 if ((error = sa6_embedscope(src, 0)) != 0 ||
187 (error = sa6_embedscope(dst, 0)) != 0)
188 break;
189
190 if (V_ipv6_hashtbl == NULL)
191 V_ipv6_hashtbl = gif_hashinit();
192 error = in6_gif_checkdup(sc, &src->sin6_addr,
193 &dst->sin6_addr);
194 if (error == EADDRNOTAVAIL)
195 break;
196 if (error == EEXIST) {
197 /* Addresses are the same. Just return. */
198 error = 0;
199 break;
200 }
201 ip6 = malloc(sizeof(*ip6), M_GIF, M_WAITOK | M_ZERO);
202 ip6->ip6_src = src->sin6_addr;
203 ip6->ip6_dst = dst->sin6_addr;
204 ip6->ip6_vfc = IPV6_VERSION;
205 if (sc->gif_family != 0) {
206 /* Detach existing tunnel first */
207 CK_LIST_REMOVE(sc, chain);
208 GIF_WAIT();
209 free(sc->gif_hdr, M_GIF);
210 /* XXX: should we notify about link state change? */
211 }
212 sc->gif_family = AF_INET6;
213 sc->gif_ip6hdr = ip6;
214 in6_gif_attach(sc);
215 break;
216 case SIOCGIFPSRCADDR_IN6:
217 case SIOCGIFPDSTADDR_IN6:
218 if (sc->gif_family != AF_INET6) {
219 error = EADDRNOTAVAIL;
220 break;
221 }
222 src = (struct sockaddr_in6 *)&ifr->ifr_addr;
223 memset(src, 0, sizeof(*src));
224 src->sin6_family = AF_INET6;
225 src->sin6_len = sizeof(*src);
226 src->sin6_addr = (cmd == SIOCGIFPSRCADDR_IN6) ?
227 sc->gif_ip6hdr->ip6_src: sc->gif_ip6hdr->ip6_dst;
228 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
229 if (error == 0)
230 error = sa6_recoverscope(src);
231 if (error != 0)
232 memset(src, 0, sizeof(*src));
233 break;
234 }
235 return (error);
236 }
237
238 int
239 in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
240 {
241 struct gif_softc *sc = ifp->if_softc;
242 struct ip6_hdr *ip6;
243 int len;
244
245 /* prepend new IP header */
246 MPASS(in_epoch(net_epoch_preempt));
247 len = sizeof(struct ip6_hdr);
248 #ifndef __NO_STRICT_ALIGNMENT
249 if (proto == IPPROTO_ETHERIP)
250 len += ETHERIP_ALIGN;
251 #endif
252 M_PREPEND(m, len, M_NOWAIT);
253 if (m == NULL)
254 return (ENOBUFS);
255 #ifndef __NO_STRICT_ALIGNMENT
256 if (proto == IPPROTO_ETHERIP) {
257 len = mtod(m, vm_offset_t) & 3;
258 KASSERT(len == 0 || len == ETHERIP_ALIGN,
259 ("in6_gif_output: unexpected misalignment"));
260 m->m_data += len;
261 m->m_len -= ETHERIP_ALIGN;
262 }
263 #endif
264
265 ip6 = mtod(m, struct ip6_hdr *);
266 MPASS(sc->gif_family == AF_INET6);
267 bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
268
269 ip6->ip6_flow |= htonl((uint32_t)ecn << 20);
270 ip6->ip6_nxt = proto;
271 ip6->ip6_hlim = V_ip6_gif_hlim;
272 /*
273 * force fragmentation to minimum MTU, to avoid path MTU discovery.
274 * it is too painful to ask for resend of inner packet, to achieve
275 * path MTU discovery for encapsulated packets.
276 */
277 return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
278 }
279
280 static int
281 in6_gif_input(struct mbuf *m, int off, int proto, void *arg)
282 {
283 struct gif_softc *sc = arg;
284 struct ifnet *gifp;
285 struct ip6_hdr *ip6;
286 uint8_t ecn;
287
288 MPASS(in_epoch(net_epoch_preempt));
289 if (sc == NULL) {
290 m_freem(m);
291 IP6STAT_INC(ip6s_nogif);
292 return (IPPROTO_DONE);
293 }
294 gifp = GIF2IFP(sc);
295 if ((gifp->if_flags & IFF_UP) != 0) {
296 ip6 = mtod(m, struct ip6_hdr *);
297 ecn = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
298 m_adj(m, off);
299 gif_input(m, gifp, proto, ecn);
300 } else {
301 m_freem(m);
302 IP6STAT_INC(ip6s_nogif);
303 }
304 return (IPPROTO_DONE);
305 }
306
307 static int
308 in6_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
309 {
310 const struct ip6_hdr *ip6;
311 struct gif_softc *sc;
312 int ret;
313
314 if (V_ipv6_hashtbl == NULL)
315 return (0);
316
317 MPASS(in_epoch(net_epoch_preempt));
318 /*
319 * NOTE: it is safe to iterate without any locking here, because softc
320 * can be reclaimed only when we are not within net_epoch_preempt
321 * section, but ip_encap lookup+input are executed in epoch section.
322 */
323 ip6 = mtod(m, const struct ip6_hdr *);
324 ret = 0;
325 CK_LIST_FOREACH(sc, &GIF_HASH(&ip6->ip6_dst, &ip6->ip6_src), chain) {
326 /*
327 * This is an inbound packet, its ip6_dst is source address
328 * in softc.
329 */
330 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
331 &ip6->ip6_dst) &&
332 IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst,
333 &ip6->ip6_src)) {
334 ret = ENCAP_DRV_LOOKUP;
335 goto done;
336 }
337 }
338 /*
339 * No exact match.
340 * Check the list of interfaces with GIF_IGNORE_SOURCE flag.
341 */
342 CK_LIST_FOREACH(sc, &V_ipv6_list, chain) {
343 if (IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src,
344 &ip6->ip6_dst)) {
345 ret = 128 + 8; /* src + proto */
346 goto done;
347 }
348 }
349 return (0);
350 done:
351 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
352 return (0);
353 /* ingress filters on outer source */
354 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
355 struct nhop6_basic nh6;
356
357 if (fib6_lookup_nh_basic(sc->gif_fibnum, &ip6->ip6_src,
358 ntohs(in6_getscope(&ip6->ip6_src)), 0, 0, &nh6) != 0)
359 return (0);
360
361 if (nh6.nh_ifp != m->m_pkthdr.rcvif)
362 return (0);
363 }
364 *arg = sc;
365 return (ret);
366 }
367
368 static struct {
369 const struct encap_config encap;
370 const struct encaptab *cookie;
371 } ipv6_encap_cfg[] = {
372 #ifdef INET
373 {
374 .encap = {
375 .proto = IPPROTO_IPV4,
376 .min_length = sizeof(struct ip6_hdr) +
377 sizeof(struct ip),
378 .exact_match = ENCAP_DRV_LOOKUP,
379 .lookup = in6_gif_lookup,
380 .input = in6_gif_input
381 },
382 },
383 #endif
384 {
385 .encap = {
386 .proto = IPPROTO_IPV6,
387 .min_length = 2 * sizeof(struct ip6_hdr),
388 .exact_match = ENCAP_DRV_LOOKUP,
389 .lookup = in6_gif_lookup,
390 .input = in6_gif_input
391 },
392 },
393 {
394 .encap = {
395 .proto = IPPROTO_ETHERIP,
396 .min_length = sizeof(struct ip6_hdr) +
397 sizeof(struct etherip_header) +
398 sizeof(struct ether_header),
399 .exact_match = ENCAP_DRV_LOOKUP,
400 .lookup = in6_gif_lookup,
401 .input = in6_gif_input
402 },
403 }
404 };
405
406 void
407 in6_gif_init(void)
408 {
409 int i;
410
411 if (!IS_DEFAULT_VNET(curvnet))
412 return;
413 for (i = 0; i < nitems(ipv6_encap_cfg); i++)
414 ipv6_encap_cfg[i].cookie = ip6_encap_attach(
415 &ipv6_encap_cfg[i].encap, NULL, M_WAITOK);
416 }
417
418 void
419 in6_gif_uninit(void)
420 {
421 int i;
422
423 if (IS_DEFAULT_VNET(curvnet)) {
424 for (i = 0; i < nitems(ipv6_encap_cfg); i++)
425 ip6_encap_detach(ipv6_encap_cfg[i].cookie);
426 }
427 if (V_ipv6_hashtbl != NULL)
428 gif_hashdestroy(V_ipv6_hashtbl);
429 }
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