FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_gif.c
1 /* $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ */
2
3 /*-
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34
35 #include "opt_mrouting.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/socket.h>
42 #include <sys/sockio.h>
43 #include <sys/mbuf.h>
44 #include <sys/errno.h>
45 #include <sys/kernel.h>
46 #include <sys/sysctl.h>
47 #include <sys/protosw.h>
48
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 #include <netinet/ip.h>
57 #include <netinet/ip_var.h>
58 #include <netinet/in_gif.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip_encap.h>
61 #include <netinet/ip_ecn.h>
62
63 #ifdef INET6
64 #include <netinet/ip6.h>
65 #endif
66
67 #ifdef MROUTING
68 #include <netinet/ip_mroute.h>
69 #endif /* MROUTING */
70
71 #include <net/if_gif.h>
72
73 static int gif_validate4(const struct ip *, struct gif_softc *,
74 struct ifnet *);
75
76 extern struct domain inetdomain;
77 struct protosw in_gif_protosw = {
78 .pr_type = SOCK_RAW,
79 .pr_domain = &inetdomain,
80 .pr_protocol = 0/* IPPROTO_IPV[46] */,
81 .pr_flags = PR_ATOMIC|PR_ADDR,
82 .pr_input = in_gif_input,
83 .pr_output = (pr_output_t*)rip_output,
84 .pr_ctloutput = rip_ctloutput,
85 .pr_usrreqs = &rip_usrreqs
86 };
87
88 static int ip_gif_ttl = GIF_TTL;
89 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
90 &ip_gif_ttl, 0, "");
91
92 int
93 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
94 {
95 struct gif_softc *sc = ifp->if_softc;
96 struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
97 struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
98 struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
99 struct ip iphdr; /* capsule IP header, host byte ordered */
100 struct etherip_header eiphdr;
101 int error, len, proto;
102 u_int8_t tos;
103
104 GIF_LOCK_ASSERT(sc);
105
106 if (sin_src == NULL || sin_dst == NULL ||
107 sin_src->sin_family != AF_INET ||
108 sin_dst->sin_family != AF_INET) {
109 m_freem(m);
110 return EAFNOSUPPORT;
111 }
112
113 switch (family) {
114 #ifdef INET
115 case AF_INET:
116 {
117 struct ip *ip;
118
119 proto = IPPROTO_IPV4;
120 if (m->m_len < sizeof(*ip)) {
121 m = m_pullup(m, sizeof(*ip));
122 if (!m)
123 return ENOBUFS;
124 }
125 ip = mtod(m, struct ip *);
126 tos = ip->ip_tos;
127 break;
128 }
129 #endif /* INET */
130 #ifdef INET6
131 case AF_INET6:
132 {
133 struct ip6_hdr *ip6;
134 proto = IPPROTO_IPV6;
135 if (m->m_len < sizeof(*ip6)) {
136 m = m_pullup(m, sizeof(*ip6));
137 if (!m)
138 return ENOBUFS;
139 }
140 ip6 = mtod(m, struct ip6_hdr *);
141 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
142 break;
143 }
144 #endif /* INET6 */
145 case AF_LINK:
146 proto = IPPROTO_ETHERIP;
147
148 /*
149 * GIF_SEND_REVETHIP (disabled by default) intentionally
150 * sends an EtherIP packet with revered version field in
151 * the header. This is a knob for backward compatibility
152 * with FreeBSD 7.2R or prior.
153 */
154 if ((sc->gif_options & GIF_SEND_REVETHIP)) {
155 eiphdr.eip_ver = 0;
156 eiphdr.eip_resvl = ETHERIP_VERSION;
157 eiphdr.eip_resvh = 0;
158 } else {
159 eiphdr.eip_ver = ETHERIP_VERSION;
160 eiphdr.eip_resvl = 0;
161 eiphdr.eip_resvh = 0;
162 }
163 /* prepend Ethernet-in-IP header */
164 M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
165 if (m && m->m_len < sizeof(struct etherip_header))
166 m = m_pullup(m, sizeof(struct etherip_header));
167 if (m == NULL)
168 return ENOBUFS;
169 bcopy(&eiphdr, mtod(m, struct etherip_header *),
170 sizeof(struct etherip_header));
171 break;
172
173 default:
174 #ifdef DEBUG
175 printf("in_gif_output: warning: unknown family %d passed\n",
176 family);
177 #endif
178 m_freem(m);
179 return EAFNOSUPPORT;
180 }
181
182 bzero(&iphdr, sizeof(iphdr));
183 iphdr.ip_src = sin_src->sin_addr;
184 /* bidirectional configured tunnel mode */
185 if (sin_dst->sin_addr.s_addr != INADDR_ANY)
186 iphdr.ip_dst = sin_dst->sin_addr;
187 else {
188 m_freem(m);
189 return ENETUNREACH;
190 }
191 iphdr.ip_p = proto;
192 /* version will be set in ip_output() */
193 iphdr.ip_ttl = ip_gif_ttl;
194 iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
195 ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
196 &iphdr.ip_tos, &tos);
197
198 /* prepend new IP header */
199 len = sizeof(struct ip);
200 #ifndef __NO_STRICT_ALIGNMENT
201 if (family == AF_LINK)
202 len += ETHERIP_ALIGN;
203 #endif
204 M_PREPEND(m, len, M_DONTWAIT);
205 if (m != NULL && m->m_len < len)
206 m = m_pullup(m, len);
207 if (m == NULL) {
208 printf("ENOBUFS in in_gif_output %d\n", __LINE__);
209 return ENOBUFS;
210 }
211 #ifndef __NO_STRICT_ALIGNMENT
212 if (family == AF_LINK) {
213 len = mtod(m, vm_offset_t) & 3;
214 KASSERT(len == 0 || len == ETHERIP_ALIGN,
215 ("in_gif_output: unexpected misalignment"));
216 m->m_data += len;
217 m->m_len -= ETHERIP_ALIGN;
218 }
219 #endif
220 bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
221
222 M_SETFIB(m, sc->gif_fibnum);
223
224 if (dst->sin_family != sin_dst->sin_family ||
225 dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
226 /* cache route doesn't match */
227 bzero(dst, sizeof(*dst));
228 dst->sin_family = sin_dst->sin_family;
229 dst->sin_len = sizeof(struct sockaddr_in);
230 dst->sin_addr = sin_dst->sin_addr;
231 if (sc->gif_ro.ro_rt) {
232 RTFREE(sc->gif_ro.ro_rt);
233 sc->gif_ro.ro_rt = NULL;
234 }
235 #if 0
236 GIF2IFP(sc)->if_mtu = GIF_MTU;
237 #endif
238 }
239
240 if (sc->gif_ro.ro_rt == NULL) {
241 in_rtalloc_ign(&sc->gif_ro, 0, sc->gif_fibnum);
242 if (sc->gif_ro.ro_rt == NULL) {
243 m_freem(m);
244 return ENETUNREACH;
245 }
246
247 /* if it constitutes infinite encapsulation, punt. */
248 if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
249 m_freem(m);
250 return ENETUNREACH; /* XXX */
251 }
252 #if 0
253 ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
254 - sizeof(struct ip);
255 #endif
256 }
257
258 error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
259
260 if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
261 sc->gif_ro.ro_rt != NULL) {
262 RTFREE(sc->gif_ro.ro_rt);
263 sc->gif_ro.ro_rt = NULL;
264 }
265
266 return (error);
267 }
268
269 void
270 in_gif_input(struct mbuf *m, int off)
271 {
272 struct ifnet *gifp = NULL;
273 struct gif_softc *sc;
274 struct ip *ip;
275 int af;
276 u_int8_t otos;
277 int proto;
278
279 ip = mtod(m, struct ip *);
280 proto = ip->ip_p;
281
282 sc = (struct gif_softc *)encap_getarg(m);
283 if (sc == NULL) {
284 m_freem(m);
285 ipstat.ips_nogif++;
286 return;
287 }
288
289 gifp = GIF2IFP(sc);
290 if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
291 m_freem(m);
292 ipstat.ips_nogif++;
293 return;
294 }
295
296 otos = ip->ip_tos;
297 m_adj(m, off);
298
299 switch (proto) {
300 #ifdef INET
301 case IPPROTO_IPV4:
302 {
303 struct ip *ip;
304 af = AF_INET;
305 if (m->m_len < sizeof(*ip)) {
306 m = m_pullup(m, sizeof(*ip));
307 if (!m)
308 return;
309 }
310 ip = mtod(m, struct ip *);
311 if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
312 ECN_ALLOWED : ECN_NOCARE,
313 &otos, &ip->ip_tos) == 0) {
314 m_freem(m);
315 return;
316 }
317 break;
318 }
319 #endif
320 #ifdef INET6
321 case IPPROTO_IPV6:
322 {
323 struct ip6_hdr *ip6;
324 u_int8_t itos, oitos;
325
326 af = AF_INET6;
327 if (m->m_len < sizeof(*ip6)) {
328 m = m_pullup(m, sizeof(*ip6));
329 if (!m)
330 return;
331 }
332 ip6 = mtod(m, struct ip6_hdr *);
333 itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
334 if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
335 ECN_ALLOWED : ECN_NOCARE,
336 &otos, &itos) == 0) {
337 m_freem(m);
338 return;
339 }
340 if (itos != oitos) {
341 ip6->ip6_flow &= ~htonl(0xff << 20);
342 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
343 }
344 break;
345 }
346 #endif /* INET6 */
347 case IPPROTO_ETHERIP:
348 af = AF_LINK;
349 break;
350
351 default:
352 ipstat.ips_nogif++;
353 m_freem(m);
354 return;
355 }
356 gif_input(m, af, gifp);
357 return;
358 }
359
360 /*
361 * validate outer address.
362 */
363 static int
364 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
365 {
366 struct sockaddr_in *src, *dst;
367 struct in_ifaddr *ia4;
368
369 src = (struct sockaddr_in *)sc->gif_psrc;
370 dst = (struct sockaddr_in *)sc->gif_pdst;
371
372 /* check for address match */
373 if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
374 dst->sin_addr.s_addr != ip->ip_src.s_addr)
375 return 0;
376
377 /* martian filters on outer source - NOT done in ip_input! */
378 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
379 return 0;
380 switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
381 case 0: case 127: case 255:
382 return 0;
383 }
384 /* reject packets with broadcast on source */
385 TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
386 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
387 continue;
388 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
389 return 0;
390 }
391
392 /* ingress filters on outer source */
393 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
394 struct sockaddr_in sin;
395 struct rtentry *rt;
396
397 bzero(&sin, sizeof(sin));
398 sin.sin_family = AF_INET;
399 sin.sin_len = sizeof(struct sockaddr_in);
400 sin.sin_addr = ip->ip_src;
401 /* XXX MRT check for the interface we would use on output */
402 rt = in_rtalloc1((struct sockaddr *)&sin, 0,
403 0UL, sc->gif_fibnum);
404 if (!rt || rt->rt_ifp != ifp) {
405 #if 0
406 log(LOG_WARNING, "%s: packet from 0x%x dropped "
407 "due to ingress filter\n", if_name(GIF2IFP(sc)),
408 (u_int32_t)ntohl(sin.sin_addr.s_addr));
409 #endif
410 if (rt)
411 RTFREE_LOCKED(rt);
412 return 0;
413 }
414 RTFREE_LOCKED(rt);
415 }
416
417 return 32 * 2;
418 }
419
420 /*
421 * we know that we are in IFF_UP, outer address available, and outer family
422 * matched the physical addr family. see gif_encapcheck().
423 */
424 int
425 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
426 {
427 struct ip ip;
428 struct gif_softc *sc;
429 struct ifnet *ifp;
430
431 /* sanity check done in caller */
432 sc = (struct gif_softc *)arg;
433
434 /* LINTED const cast */
435 m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
436 ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
437
438 return gif_validate4(&ip, sc, ifp);
439 }
440
441 int
442 in_gif_attach(struct gif_softc *sc)
443 {
444 sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
445 &in_gif_protosw, sc);
446 if (sc->encap_cookie4 == NULL)
447 return EEXIST;
448 return 0;
449 }
450
451 int
452 in_gif_detach(struct gif_softc *sc)
453 {
454 int error;
455
456 error = encap_detach(sc->encap_cookie4);
457 if (error == 0)
458 sc->encap_cookie4 = NULL;
459 return error;
460 }
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