xref: /dragonfly/sys/netinet/in_gif.c (revision 029a4939) 
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 1.13 2005/01/06 17:59:32 hsu 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 const 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(struct ifnet *ifp, int family, struct mbuf *m)
91 {
92 	struct gif_softc *sc = (struct gif_softc*)ifp;
93 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
94 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
95 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
96 	struct ip iphdr;	/* capsule IP header, host byte ordered */
97 	int proto, error;
98 	u_int8_t tos;
99 
100 	if (sin_src == NULL || sin_dst == NULL ||
101 	    sin_src->sin_family != AF_INET ||
102 	    sin_dst->sin_family != AF_INET) {
103 		m_freem(m);
104 		return EAFNOSUPPORT;
105 	}
106 
107 	switch (family) {
108 #ifdef INET
109 	case AF_INET:
110 	    {
111 		struct ip *ip;
112 
113 		proto = IPPROTO_IPV4;
114 		if (m->m_len < sizeof *ip) {
115 			m = m_pullup(m, sizeof *ip);
116 			if (!m)
117 				return ENOBUFS;
118 		}
119 		ip = mtod(m, struct ip *);
120 		tos = ip->ip_tos;
121 		break;
122 	    }
123 #endif /* INET */
124 #ifdef INET6
125 	case AF_INET6:
126 	    {
127 		struct ip6_hdr *ip6;
128 		proto = IPPROTO_IPV6;
129 		if (m->m_len < sizeof *ip6) {
130 			m = m_pullup(m, sizeof *ip6);
131 			if (!m)
132 				return ENOBUFS;
133 		}
134 		ip6 = mtod(m, struct ip6_hdr *);
135 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
136 		break;
137 	    }
138 #endif /* INET6 */
139 	default:
140 #ifdef DEBUG
141 		printf("in_gif_output: warning: unknown family %d passed\n",
142 			family);
143 #endif
144 		m_freem(m);
145 		return EAFNOSUPPORT;
146 	}
147 
148 	bzero(&iphdr, sizeof iphdr);
149 	iphdr.ip_src = sin_src->sin_addr;
150 	/* bidirectional configured tunnel mode */
151 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
152 		iphdr.ip_dst = sin_dst->sin_addr;
153 	else {
154 		m_freem(m);
155 		return ENETUNREACH;
156 	}
157 	iphdr.ip_p = proto;
158 	/* version will be set in ip_output() */
159 	iphdr.ip_ttl = ip_gif_ttl;
160 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
161 	if (ifp->if_flags & IFF_LINK1)
162 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
163 	else
164 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
165 
166 	/* prepend new IP header */
167 	M_PREPEND(m, sizeof(struct ip), MB_DONTWAIT);
168 	if (m && m->m_len < sizeof(struct ip))
169 		m = m_pullup(m, sizeof(struct ip));
170 	if (m == NULL) {
171 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
172 		return ENOBUFS;
173 	}
174 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
175 
176 	if (dst->sin_family != sin_dst->sin_family ||
177 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
178 		/* cache route doesn't match */
179 		dst->sin_family = sin_dst->sin_family;
180 		dst->sin_len = sizeof(struct sockaddr_in);
181 		dst->sin_addr = sin_dst->sin_addr;
182 		if (sc->gif_ro.ro_rt) {
183 			RTFREE(sc->gif_ro.ro_rt);
184 			sc->gif_ro.ro_rt = NULL;
185 		}
186 #if 0
187 		sc->gif_if.if_mtu = GIF_MTU;
188 #endif
189 	}
190 
191 	if (sc->gif_ro.ro_rt == NULL) {
192 		rtalloc(&sc->gif_ro);
193 		if (sc->gif_ro.ro_rt == NULL) {
194 			m_freem(m);
195 			return ENETUNREACH;
196 		}
197 
198 		/* if it constitutes infinite encapsulation, punt. */
199 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
200 			m_freem(m);
201 			return ENETUNREACH;	/* XXX */
202 		}
203 #if 0
204 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu -
205 		    sizeof(struct ip);
206 #endif
207 	}
208 
209 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
210 	return(error);
211 }
212 
213 void
214 in_gif_input(struct mbuf *m, ...)
215 {
216 	struct ifnet *gifp = NULL;
217 	struct ip *ip;
218 	int af;
219 	u_int8_t otos;
220 	int off, proto;
221 	__va_list ap;
222 
223 	__va_start(ap, m);
224 	off = __va_arg(ap, int);
225 	proto = __va_arg(ap, int);
226 	__va_end(ap);
227 
228 	ip = mtod(m, struct ip *);
229 
230 	gifp = (struct ifnet *)encap_getarg(m);
231 
232 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
233 		m_freem(m);
234 		ipstat.ips_nogif++;
235 		return;
236 	}
237 
238 	otos = ip->ip_tos;
239 	m_adj(m, off);
240 
241 	switch (proto) {
242 #ifdef INET
243 	case IPPROTO_IPV4:
244 	    {
245 		struct ip *ip;
246 		af = AF_INET;
247 		if (m->m_len < sizeof *ip) {
248 			m = m_pullup(m, sizeof *ip);
249 			if (!m)
250 				return;
251 		}
252 		ip = mtod(m, struct ip *);
253 		if (gifp->if_flags & IFF_LINK1)
254 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
255 		else
256 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
257 		break;
258 	    }
259 #endif
260 #ifdef INET6
261 	case IPPROTO_IPV6:
262 	    {
263 		struct ip6_hdr *ip6;
264 		u_int8_t itos;
265 		af = AF_INET6;
266 		if (m->m_len < sizeof *ip6) {
267 			m = m_pullup(m, sizeof *ip6);
268 			if (!m)
269 				return;
270 		}
271 		ip6 = mtod(m, struct ip6_hdr *);
272 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
273 		if (gifp->if_flags & IFF_LINK1)
274 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
275 		else
276 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
277 		ip6->ip6_flow &= ~htonl(0xff << 20);
278 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
279 		break;
280 	    }
281 #endif /* INET6 */
282 	default:
283 		ipstat.ips_nogif++;
284 		m_freem(m);
285 		return;
286 	}
287 	gif_input(m, af, gifp);
288 	return;
289 }
290 
291 /*
292  * validate outer address.
293  */
294 static int
295 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
296 {
297 	struct sockaddr_in *src, *dst;
298 	struct in_ifaddr *ia4;
299 
300 	src = (struct sockaddr_in *)sc->gif_psrc;
301 	dst = (struct sockaddr_in *)sc->gif_pdst;
302 
303 	/* check for address match */
304 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
305 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
306 		return 0;
307 
308 	/* martian filters on outer source - NOT done in ip_input! */
309 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
310 		return 0;
311 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
312 	case 0: case 127: case 255:
313 		return 0;
314 	}
315 	/* reject packets with broadcast on source */
316 	for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
317 	     ia4 = TAILQ_NEXT(ia4, ia_link))
318 	{
319 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
320 			continue;
321 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
322 			return 0;
323 	}
324 
325 	/* ingress filters on outer source */
326 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
327 		struct sockaddr_in sin;
328 		struct rtentry *rt;
329 
330 		bzero(&sin, sizeof sin);
331 		sin.sin_family = AF_INET;
332 		sin.sin_len = sizeof(struct sockaddr_in);
333 		sin.sin_addr = ip->ip_src;
334 		rt = rtpurelookup((struct sockaddr *)&sin);
335 		if (!rt || rt->rt_ifp != ifp) {
336 #if 0
337 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
338 			    "due to ingress filter\n", if_name(&sc->gif_if),
339 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
340 #endif
341 			if (rt)
342 				--rt->rt_refcnt;
343 			return 0;
344 		}
345 		--rt->rt_refcnt;
346 	}
347 
348 	return 32 * 2;
349 }
350 
351 /*
352  * we know that we are in IFF_UP, outer address available, and outer family
353  * matched the physical addr family.  see gif_encapcheck().
354  */
355 int
356 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
357 {
358 	struct ip ip;
359 	struct gif_softc *sc;
360 	struct ifnet *ifp;
361 
362 	/* sanity check done in caller */
363 	sc = (struct gif_softc *)arg;
364 
365 	/* LINTED const cast */
366 	m_copydata(__DECONST(struct mbuf *, m), 0, sizeof ip, (caddr_t)&ip);
367 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
368 
369 	return gif_validate4(&ip, sc, ifp);
370 }
371 
372 int
373 in_gif_attach(struct gif_softc *sc)
374 {
375 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
376 	    &in_gif_protosw, sc);
377 	if (sc->encap_cookie4 == NULL)
378 		return EEXIST;
379 	return 0;
380 }
381 
382 int
383 in_gif_detach(struct gif_softc *sc)
384 {
385 	int error;
386 
387 	error = encap_detach(sc->encap_cookie4);
388 	if (error == 0)
389 		sc->encap_cookie4 = NULL;
390 	return error;
391 }
392