1 /*-
2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the project nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/8.4/sys/netinet6/in6_gif.c 232552 2012-03-05 17:33:01Z bz $");
34
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/socket.h>
41 #include <sys/sockio.h>
42 #include <sys/mbuf.h>
43 #include <sys/errno.h>
44 #include <sys/kernel.h>
45 #include <sys/queue.h>
46 #include <sys/syslog.h>
47 #include <sys/sysctl.h>
48 #include <sys/protosw.h>
49 #include <sys/malloc.h>
50
51 #include <net/if.h>
52 #include <net/route.h>
53
54 #include <netinet/in.h>
55 #include <netinet/in_systm.h>
56 #ifdef INET
57 #include <netinet/ip.h>
58 #endif
59 #include <netinet/ip_encap.h>
60 #ifdef INET6
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet6/in6_gif.h>
64 #include <netinet6/in6_var.h>
65 #endif
66 #include <netinet6/ip6protosw.h>
67 #include <netinet/ip_ecn.h>
68 #ifdef INET6
69 #include <netinet6/ip6_ecn.h>
70 #endif
71
72 #include <net/if_gif.h>
73
74 VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
75 #define V_ip6_gif_hlim VNET(ip6_gif_hlim)
76
77 SYSCTL_DECL(_net_inet6_ip6);
78 SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_RW,
79 &VNET_NAME(ip6_gif_hlim), 0, "");
80
81 static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
82 struct ifnet *);
83
84 extern struct domain inet6domain;
85 struct ip6protosw in6_gif_protosw = {
86 .pr_type = SOCK_RAW,
87 .pr_domain = &inet6domain,
88 .pr_protocol = 0, /* IPPROTO_IPV[46] */
89 .pr_flags = PR_ATOMIC|PR_ADDR,
90 .pr_input = in6_gif_input,
91 .pr_output = rip6_output,
92 .pr_ctloutput = rip6_ctloutput,
93 .pr_usrreqs = &rip6_usrreqs
94 };
95
96 int
97 in6_gif_output(struct ifnet *ifp,
98 int family, /* family of the packet to be encapsulate */
99 struct mbuf *m)
100 {
101 struct gif_softc *sc = ifp->if_softc;
102 struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
103 struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
104 struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
105 struct ip6_hdr *ip6;
106 struct etherip_header eiphdr;
107 int error, len, proto;
108 u_int8_t itos, otos;
109
110 GIF_LOCK_ASSERT(sc);
111
112 if (sin6_src == NULL || sin6_dst == NULL ||
113 sin6_src->sin6_family != AF_INET6 ||
114 sin6_dst->sin6_family != AF_INET6) {
115 m_freem(m);
116 return EAFNOSUPPORT;
117 }
118
119 switch (family) {
120 #ifdef INET
121 case AF_INET:
122 {
123 struct ip *ip;
124
125 proto = IPPROTO_IPV4;
126 if (m->m_len < sizeof(*ip)) {
127 m = m_pullup(m, sizeof(*ip));
128 if (!m)
129 return ENOBUFS;
130 }
131 ip = mtod(m, struct ip *);
132 itos = ip->ip_tos;
133 break;
134 }
135 #endif
136 #ifdef INET6
137 case AF_INET6:
138 {
139 struct ip6_hdr *ip6;
140 proto = IPPROTO_IPV6;
141 if (m->m_len < sizeof(*ip6)) {
142 m = m_pullup(m, sizeof(*ip6));
143 if (!m)
144 return ENOBUFS;
145 }
146 ip6 = mtod(m, struct ip6_hdr *);
147 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
148 break;
149 }
150 #endif
151 case AF_LINK:
152 proto = IPPROTO_ETHERIP;
153
154 /*
155 * GIF_SEND_REVETHIP (disabled by default) intentionally
156 * sends an EtherIP packet with revered version field in
157 * the header. This is a knob for backward compatibility
158 * with FreeBSD 7.2R or prior.
159 */
160 if ((sc->gif_options & GIF_SEND_REVETHIP)) {
161 eiphdr.eip_ver = 0;
162 eiphdr.eip_resvl = ETHERIP_VERSION;
163 eiphdr.eip_resvh = 0;
164 } else {
165 eiphdr.eip_ver = ETHERIP_VERSION;
166 eiphdr.eip_resvl = 0;
167 eiphdr.eip_resvh = 0;
168 }
169 /* prepend Ethernet-in-IP header */
170 M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
171 if (m && m->m_len < sizeof(struct etherip_header))
172 m = m_pullup(m, sizeof(struct etherip_header));
173 if (m == NULL)
174 return ENOBUFS;
175 bcopy(&eiphdr, mtod(m, struct etherip_header *),
176 sizeof(struct etherip_header));
177 break;
178
179 default:
180 #ifdef DEBUG
181 printf("in6_gif_output: warning: unknown family %d passed\n",
182 family);
183 #endif
184 m_freem(m);
185 return EAFNOSUPPORT;
186 }
187
188 /* prepend new IP header */
189 len = sizeof(struct ip6_hdr);
190 #ifndef __NO_STRICT_ALIGNMENT
191 if (family == AF_LINK)
192 len += ETHERIP_ALIGN;
193 #endif
194 M_PREPEND(m, len, M_DONTWAIT);
195 if (m != NULL && m->m_len < len)
196 m = m_pullup(m, len);
197 if (m == NULL) {
198 printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
199 return ENOBUFS;
200 }
201 #ifndef __NO_STRICT_ALIGNMENT
202 if (family == AF_LINK) {
203 len = mtod(m, vm_offset_t) & 3;
204 KASSERT(len == 0 || len == ETHERIP_ALIGN,
205 ("in6_gif_output: unexpected misalignment"));
206 m->m_data += len;
207 m->m_len -= ETHERIP_ALIGN;
208 }
209 #endif
210
211 ip6 = mtod(m, struct ip6_hdr *);
212 ip6->ip6_flow = 0;
213 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
214 ip6->ip6_vfc |= IPV6_VERSION;
215 ip6->ip6_plen = htons((u_short)m->m_pkthdr.len);
216 ip6->ip6_nxt = proto;
217 ip6->ip6_hlim = V_ip6_gif_hlim;
218 ip6->ip6_src = sin6_src->sin6_addr;
219 /* bidirectional configured tunnel mode */
220 if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
221 ip6->ip6_dst = sin6_dst->sin6_addr;
222 else {
223 m_freem(m);
224 return ENETUNREACH;
225 }
226 ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
227 &otos, &itos);
228 ip6->ip6_flow &= ~htonl(0xff << 20);
229 ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
230
231 M_SETFIB(m, sc->gif_fibnum);
232
233 if (dst->sin6_family != sin6_dst->sin6_family ||
234 !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
235 /* cache route doesn't match */
236 bzero(dst, sizeof(*dst));
237 dst->sin6_family = sin6_dst->sin6_family;
238 dst->sin6_len = sizeof(struct sockaddr_in6);
239 dst->sin6_addr = sin6_dst->sin6_addr;
240 if (sc->gif_ro6.ro_rt) {
241 RTFREE(sc->gif_ro6.ro_rt);
242 sc->gif_ro6.ro_rt = NULL;
243 }
244 #if 0
245 GIF2IFP(sc)->if_mtu = GIF_MTU;
246 #endif
247 }
248
249 if (sc->gif_ro6.ro_rt == NULL) {
250 in6_rtalloc(&sc->gif_ro6, sc->gif_fibnum);
251 if (sc->gif_ro6.ro_rt == NULL) {
252 m_freem(m);
253 return ENETUNREACH;
254 }
255
256 /* if it constitutes infinite encapsulation, punt. */
257 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
258 m_freem(m);
259 return ENETUNREACH; /*XXX*/
260 }
261 #if 0
262 ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
263 - sizeof(struct ip6_hdr);
264 #endif
265 }
266
267 #ifdef IPV6_MINMTU
268 /*
269 * force fragmentation to minimum MTU, to avoid path MTU discovery.
270 * it is too painful to ask for resend of inner packet, to achieve
271 * path MTU discovery for encapsulated packets.
272 */
273 error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
274 #else
275 error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
276 #endif
277
278 if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
279 sc->gif_ro6.ro_rt != NULL) {
280 RTFREE(sc->gif_ro6.ro_rt);
281 sc->gif_ro6.ro_rt = NULL;
282 }
283
284 return (error);
285 }
286
287 int
288 in6_gif_input(struct mbuf **mp, int *offp, int proto)
289 {
290 struct mbuf *m = *mp;
291 struct ifnet *gifp = NULL;
292 struct gif_softc *sc;
293 struct ip6_hdr *ip6;
294 int af = 0;
295 u_int32_t otos;
296
297 ip6 = mtod(m, struct ip6_hdr *);
298
299 sc = (struct gif_softc *)encap_getarg(m);
300 if (sc == NULL) {
301 m_freem(m);
302 V_ip6stat.ip6s_nogif++;
303 return IPPROTO_DONE;
304 }
305
306 gifp = GIF2IFP(sc);
307 if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
308 m_freem(m);
309 V_ip6stat.ip6s_nogif++;
310 return IPPROTO_DONE;
311 }
312
313 otos = ip6->ip6_flow;
314 m_adj(m, *offp);
315
316 switch (proto) {
317 #ifdef INET
318 case IPPROTO_IPV4:
319 {
320 struct ip *ip;
321 u_int8_t otos8;
322 af = AF_INET;
323 otos8 = (ntohl(otos) >> 20) & 0xff;
324 if (m->m_len < sizeof(*ip)) {
325 m = m_pullup(m, sizeof(*ip));
326 if (!m)
327 return IPPROTO_DONE;
328 }
329 ip = mtod(m, struct ip *);
330 if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
331 ECN_ALLOWED : ECN_NOCARE,
332 &otos8, &ip->ip_tos) == 0) {
333 m_freem(m);
334 return IPPROTO_DONE;
335 }
336 break;
337 }
338 #endif /* INET */
339 #ifdef INET6
340 case IPPROTO_IPV6:
341 {
342 struct ip6_hdr *ip6;
343 af = AF_INET6;
344 if (m->m_len < sizeof(*ip6)) {
345 m = m_pullup(m, sizeof(*ip6));
346 if (!m)
347 return IPPROTO_DONE;
348 }
349 ip6 = mtod(m, struct ip6_hdr *);
350 if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
351 ECN_ALLOWED : ECN_NOCARE,
352 &otos, &ip6->ip6_flow) == 0) {
353 m_freem(m);
354 return IPPROTO_DONE;
355 }
356 break;
357 }
358 #endif
359 case IPPROTO_ETHERIP:
360 af = AF_LINK;
361 break;
362
363 default:
364 V_ip6stat.ip6s_nogif++;
365 m_freem(m);
366 return IPPROTO_DONE;
367 }
368
369 gif_input(m, af, gifp);
370 return IPPROTO_DONE;
371 }
372
373 /*
374 * validate outer address.
375 */
376 static int
377 gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
378 struct ifnet *ifp)
379 {
380 struct sockaddr_in6 *src, *dst;
381
382 src = (struct sockaddr_in6 *)sc->gif_psrc;
383 dst = (struct sockaddr_in6 *)sc->gif_pdst;
384
385 /*
386 * Check for address match. Note that the check is for an incoming
387 * packet. We should compare the *source* address in our configuration
388 * and the *destination* address of the packet, and vice versa.
389 */
390 if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
391 !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
392 return 0;
393
394 /* martian filters on outer source - done in ip6_input */
395
396 /* ingress filters on outer source */
397 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
398 struct sockaddr_in6 sin6;
399 struct rtentry *rt;
400
401 bzero(&sin6, sizeof(sin6));
402 sin6.sin6_family = AF_INET6;
403 sin6.sin6_len = sizeof(struct sockaddr_in6);
404 sin6.sin6_addr = ip6->ip6_src;
405 sin6.sin6_scope_id = 0; /* XXX */
406
407 rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL,
408 sc->gif_fibnum);
409 if (!rt || rt->rt_ifp != ifp) {
410 #if 0
411 char ip6buf[INET6_ADDRSTRLEN];
412 log(LOG_WARNING, "%s: packet from %s dropped "
413 "due to ingress filter\n", if_name(GIF2IFP(sc)),
414 ip6_sprintf(ip6buf, &sin6.sin6_addr));
415 #endif
416 if (rt)
417 RTFREE_LOCKED(rt);
418 return 0;
419 }
420 RTFREE_LOCKED(rt);
421 }
422
423 return 128 * 2;
424 }
425
426 /*
427 * we know that we are in IFF_UP, outer address available, and outer family
428 * matched the physical addr family. see gif_encapcheck().
429 * sanity check for arg should have been done in the caller.
430 */
431 int
432 gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
433 {
434 struct ip6_hdr ip6;
435 struct gif_softc *sc;
436 struct ifnet *ifp;
437
438 /* sanity check done in caller */
439 sc = (struct gif_softc *)arg;
440
441 /* LINTED const cast */
442 m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
443 ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
444
445 return gif_validate6(&ip6, sc, ifp);
446 }
447
448 int
449 in6_gif_attach(struct gif_softc *sc)
450 {
451 sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
452 (void *)&in6_gif_protosw, sc);
453 if (sc->encap_cookie6 == NULL)
454 return EEXIST;
455 return 0;
456 }
457
458 int
459 in6_gif_detach(struct gif_softc *sc)
460 {
461 int error;
462
463 error = encap_detach(sc->encap_cookie6);
464 if (error == 0)
465 sc->encap_cookie6 = NULL;
466 return error;
467 }
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