xref: /dragonfly/sys/netinet/in_gif.c (revision 2cd2d2b5) 
1 /*
2  * $FreeBSD: src/sys/netinet/in_gif.c,v 1.5.2.11 2003/01/23 21:06:45 sam Exp $
3  * $DragonFly: src/sys/netinet/in_gif.c,v 1.10 2004/06/03 18:30:03 joerg Exp $
4  * $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $
5  */
6 /*
7  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the project nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
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/sysctl.h>
46 #include <sys/protosw.h>
47 
48 #include <sys/malloc.h>
49 
50 #include <machine/stdarg.h>
51 
52 #include <net/if.h>
53 #include <net/route.h>
54 
55 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 #include <netinet/ip_var.h>
59 #include <netinet/in_gif.h>
60 #include <netinet/in_var.h>
61 #include <netinet/ip_encap.h>
62 #include <netinet/ip_ecn.h>
63 
64 #ifdef INET6
65 #include <netinet/ip6.h>
66 #endif
67 
68 #include <net/gif/if_gif.h>
69 #include <net/net_osdep.h>
70 
71 #include <sys/thread2.h>	/* ipstat */
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 { SOCK_RAW,	&inetdomain,	0/*IPPROTO_IPV[46]*/,	PR_ATOMIC|PR_ADDR,
79   in_gif_input, rip_output,	0,	rip_ctloutput,
80   cpu0_soport,
81   0,		0,		0,		0,
82   &rip_usrreqs
83 };
84 
85 int ip_gif_ttl = GIF_TTL;
86 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
87 	&ip_gif_ttl,	0, "");
88 
89 int
90 in_gif_output(ifp, family, m)
91 	struct ifnet	*ifp;
92 	int		family;
93 	struct mbuf	*m;
94 {
95 	struct gif_softc *sc = (struct gif_softc*)ifp;
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 	int proto, error;
101 	u_int8_t tos;
102 
103 	if (sin_src == NULL || sin_dst == NULL ||
104 	    sin_src->sin_family != AF_INET ||
105 	    sin_dst->sin_family != AF_INET) {
106 		m_freem(m);
107 		return EAFNOSUPPORT;
108 	}
109 
110 	switch (family) {
111 #ifdef INET
112 	case AF_INET:
113 	    {
114 		struct ip *ip;
115 
116 		proto = IPPROTO_IPV4;
117 		if (m->m_len < sizeof(*ip)) {
118 			m = m_pullup(m, sizeof(*ip));
119 			if (!m)
120 				return ENOBUFS;
121 		}
122 		ip = mtod(m, struct ip *);
123 		tos = ip->ip_tos;
124 		break;
125 	    }
126 #endif /* INET */
127 #ifdef INET6
128 	case AF_INET6:
129 	    {
130 		struct ip6_hdr *ip6;
131 		proto = IPPROTO_IPV6;
132 		if (m->m_len < sizeof(*ip6)) {
133 			m = m_pullup(m, sizeof(*ip6));
134 			if (!m)
135 				return ENOBUFS;
136 		}
137 		ip6 = mtod(m, struct ip6_hdr *);
138 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
139 		break;
140 	    }
141 #endif /* INET6 */
142 	default:
143 #ifdef DEBUG
144 		printf("in_gif_output: warning: unknown family %d passed\n",
145 			family);
146 #endif
147 		m_freem(m);
148 		return EAFNOSUPPORT;
149 	}
150 
151 	bzero(&iphdr, sizeof(iphdr));
152 	iphdr.ip_src = sin_src->sin_addr;
153 	/* bidirectional configured tunnel mode */
154 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
155 		iphdr.ip_dst = sin_dst->sin_addr;
156 	else {
157 		m_freem(m);
158 		return ENETUNREACH;
159 	}
160 	iphdr.ip_p = proto;
161 	/* version will be set in ip_output() */
162 	iphdr.ip_ttl = ip_gif_ttl;
163 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
164 	if (ifp->if_flags & IFF_LINK1)
165 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
166 	else
167 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
168 
169 	/* prepend new IP header */
170 	M_PREPEND(m, sizeof(struct ip), MB_DONTWAIT);
171 	if (m && m->m_len < sizeof(struct ip))
172 		m = m_pullup(m, sizeof(struct ip));
173 	if (m == NULL) {
174 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
175 		return ENOBUFS;
176 	}
177 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
178 
179 	if (dst->sin_family != sin_dst->sin_family ||
180 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
181 		/* cache route doesn't match */
182 		dst->sin_family = sin_dst->sin_family;
183 		dst->sin_len = sizeof(struct sockaddr_in);
184 		dst->sin_addr = sin_dst->sin_addr;
185 		if (sc->gif_ro.ro_rt) {
186 			RTFREE(sc->gif_ro.ro_rt);
187 			sc->gif_ro.ro_rt = NULL;
188 		}
189 #if 0
190 		sc->gif_if.if_mtu = GIF_MTU;
191 #endif
192 	}
193 
194 	if (sc->gif_ro.ro_rt == NULL) {
195 		rtalloc(&sc->gif_ro);
196 		if (sc->gif_ro.ro_rt == NULL) {
197 			m_freem(m);
198 			return ENETUNREACH;
199 		}
200 
201 		/* if it constitutes infinite encapsulation, punt. */
202 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
203 			m_freem(m);
204 			return ENETUNREACH;	/* XXX */
205 		}
206 #if 0
207 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
208 			- sizeof(struct ip);
209 #endif
210 	}
211 
212 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
213 	return(error);
214 }
215 
216 void
217 in_gif_input(struct mbuf *m, ...)
218 {
219 	struct ifnet *gifp = NULL;
220 	struct ip *ip;
221 	int af;
222 	u_int8_t otos;
223 	int off, proto;
224 	__va_list ap;
225 
226 	__va_start(ap, m);
227 	off = __va_arg(ap, int);
228 	proto = __va_arg(ap, int);
229 	__va_end(ap);
230 
231 	ip = mtod(m, struct ip *);
232 
233 	gifp = (struct ifnet *)encap_getarg(m);
234 
235 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
236 		m_freem(m);
237 		ipstat.ips_nogif++;
238 		return;
239 	}
240 
241 	otos = ip->ip_tos;
242 	m_adj(m, off);
243 
244 	switch (proto) {
245 #ifdef INET
246 	case IPPROTO_IPV4:
247 	    {
248 		struct ip *ip;
249 		af = AF_INET;
250 		if (m->m_len < sizeof(*ip)) {
251 			m = m_pullup(m, sizeof(*ip));
252 			if (!m)
253 				return;
254 		}
255 		ip = mtod(m, struct ip *);
256 		if (gifp->if_flags & IFF_LINK1)
257 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
258 		else
259 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
260 		break;
261 	    }
262 #endif
263 #ifdef INET6
264 	case IPPROTO_IPV6:
265 	    {
266 		struct ip6_hdr *ip6;
267 		u_int8_t itos;
268 		af = AF_INET6;
269 		if (m->m_len < sizeof(*ip6)) {
270 			m = m_pullup(m, sizeof(*ip6));
271 			if (!m)
272 				return;
273 		}
274 		ip6 = mtod(m, struct ip6_hdr *);
275 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
276 		if (gifp->if_flags & IFF_LINK1)
277 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
278 		else
279 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
280 		ip6->ip6_flow &= ~htonl(0xff << 20);
281 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
282 		break;
283 	    }
284 #endif /* INET6 */
285 	default:
286 		ipstat.ips_nogif++;
287 		m_freem(m);
288 		return;
289 	}
290 	gif_input(m, af, gifp);
291 	return;
292 }
293 
294 /*
295  * validate outer address.
296  */
297 static int
298 gif_validate4(ip, sc, ifp)
299 	const struct ip *ip;
300 	struct gif_softc *sc;
301 	struct ifnet *ifp;
302 {
303 	struct sockaddr_in *src, *dst;
304 	struct in_ifaddr *ia4;
305 
306 	src = (struct sockaddr_in *)sc->gif_psrc;
307 	dst = (struct sockaddr_in *)sc->gif_pdst;
308 
309 	/* check for address match */
310 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
311 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
312 		return 0;
313 
314 	/* martian filters on outer source - NOT done in ip_input! */
315 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
316 		return 0;
317 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
318 	case 0: case 127: case 255:
319 		return 0;
320 	}
321 	/* reject packets with broadcast on source */
322 	for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
323 	     ia4 = TAILQ_NEXT(ia4, ia_link))
324 	{
325 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
326 			continue;
327 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
328 			return 0;
329 	}
330 
331 	/* ingress filters on outer source */
332 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
333 		struct sockaddr_in sin;
334 		struct rtentry *rt;
335 
336 		bzero(&sin, sizeof(sin));
337 		sin.sin_family = AF_INET;
338 		sin.sin_len = sizeof(struct sockaddr_in);
339 		sin.sin_addr = ip->ip_src;
340 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
341 		if (!rt || rt->rt_ifp != ifp) {
342 #if 0
343 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
344 			    "due to ingress filter\n", if_name(&sc->gif_if),
345 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
346 #endif
347 			if (rt)
348 				rtfree(rt);
349 			return 0;
350 		}
351 		rtfree(rt);
352 	}
353 
354 	return 32 * 2;
355 }
356 
357 /*
358  * we know that we are in IFF_UP, outer address available, and outer family
359  * matched the physical addr family.  see gif_encapcheck().
360  */
361 int
362 gif_encapcheck4(m, off, proto, arg)
363 	const struct mbuf *m;
364 	int off;
365 	int proto;
366 	void *arg;
367 {
368 	struct ip ip;
369 	struct gif_softc *sc;
370 	struct ifnet *ifp;
371 
372 	/* sanity check done in caller */
373 	sc = (struct gif_softc *)arg;
374 
375 	/* LINTED const cast */
376 	m_copydata(__DECONST(struct mbuf *, m), 0, sizeof(ip), (caddr_t)&ip);
377 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
378 
379 	return gif_validate4(&ip, sc, ifp);
380 }
381 
382 int
383 in_gif_attach(sc)
384 	struct gif_softc *sc;
385 {
386 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
387 	    &in_gif_protosw, sc);
388 	if (sc->encap_cookie4 == NULL)
389 		return EEXIST;
390 	return 0;
391 }
392 
393 int
394 in_gif_detach(sc)
395 	struct gif_softc *sc;
396 {
397 	int error;
398 
399 	error = encap_detach(sc->encap_cookie4);
400 	if (error == 0)
401 		sc->encap_cookie4 = NULL;
402 	return error;
403 }
404