xref: /dragonfly/sys/netinet/in_gif.c (revision b8c93cad) 
1 /*
2  * $FreeBSD: src/sys/netinet/in_gif.c,v 1.5.2.11 2003/01/23 21:06:45 sam Exp $
3  * $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $
4  */
5 /*
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include "opt_inet.h"
35 #include "opt_inet6.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/socket.h>
40 #include <sys/sockio.h>
41 #include <sys/mbuf.h>
42 #include <sys/errno.h>
43 #include <sys/kernel.h>
44 #include <sys/sysctl.h>
45 #include <sys/protosw.h>
46 
47 #include <sys/malloc.h>
48 
49 #include <machine/stdarg.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 #include <net/gif/if_gif.h>
68 #include <net/net_osdep.h>
69 
70 #include <sys/thread2.h>	/* ipstat */
71 
72 #ifdef INET
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     {
79 	.pr_type = SOCK_RAW,
80 	.pr_domain = &inetdomain,
81 	.pr_protocol = 0 /*IPPROTO_IPV[46]*/,
82 	.pr_flags = PR_ATOMIC|PR_ADDR,
83 
84 	.pr_input = in_gif_input,
85 	.pr_output = rip_output,
86 	.pr_ctlinput = NULL,
87 	.pr_ctloutput = rip_ctloutput,
88 
89 	.pr_ctlport = NULL,
90 	.pr_usrreqs = &rip_usrreqs
91     };
92 
93 int ip_gif_ttl = GIF_TTL;
94 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
95 	&ip_gif_ttl, 0, "TTL of GIF packet");
96 
97 int
98 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
99 {
100 	struct gif_softc *sc = (struct gif_softc*)ifp;
101 	struct route *ro = &sc->gif_ro[mycpu->gd_cpuid];
102 	struct sockaddr_in *dst = (struct sockaddr_in *)&ro->ro_dst;
103 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
104 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
105 	struct ip iphdr;	/* capsule IP header, host byte ordered */
106 	int proto, error;
107 	u_int8_t tos;
108 
109 	if (sin_src == NULL || sin_dst == NULL ||
110 	    sin_src->sin_family != AF_INET ||
111 	    sin_dst->sin_family != AF_INET) {
112 		m_freem(m);
113 		return EAFNOSUPPORT;
114 	}
115 
116 	switch (family) {
117 #ifdef INET
118 	case AF_INET:
119 	    {
120 		struct ip *ip;
121 
122 		proto = IPPROTO_IPV4;
123 		if (m->m_len < sizeof *ip) {
124 			m = m_pullup(m, sizeof *ip);
125 			if (!m)
126 				return ENOBUFS;
127 		}
128 		ip = mtod(m, struct ip *);
129 		tos = ip->ip_tos;
130 		break;
131 	    }
132 #endif
133 #ifdef INET6
134 	case AF_INET6:
135 	    {
136 		struct ip6_hdr *ip6;
137 		proto = IPPROTO_IPV6;
138 		if (m->m_len < sizeof *ip6) {
139 			m = m_pullup(m, sizeof *ip6);
140 			if (!m)
141 				return ENOBUFS;
142 		}
143 		ip6 = mtod(m, struct ip6_hdr *);
144 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
145 		break;
146 	    }
147 #endif
148 	default:
149 #ifdef DEBUG
150 		kprintf("in_gif_output: warning: unknown family %d passed\n",
151 			family);
152 #endif
153 		m_freem(m);
154 		return EAFNOSUPPORT;
155 	}
156 
157 	bzero(&iphdr, sizeof iphdr);
158 	iphdr.ip_src = sin_src->sin_addr;
159 	/* bidirectional configured tunnel mode */
160 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
161 		iphdr.ip_dst = sin_dst->sin_addr;
162 	else {
163 		m_freem(m);
164 		return ENETUNREACH;
165 	}
166 	iphdr.ip_p = proto;
167 	/* version will be set in ip_output() */
168 	iphdr.ip_ttl = ip_gif_ttl;
169 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
170 	if (ifp->if_flags & IFF_LINK1)
171 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
172 	else
173 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
174 
175 	/* prepend new IP header */
176 	M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
177 	if (m && m->m_len < sizeof(struct ip))
178 		m = m_pullup(m, sizeof(struct ip));
179 	if (m == NULL) {
180 		kprintf("ENOBUFS in in_gif_output %d\n", __LINE__);
181 		return ENOBUFS;
182 	}
183 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
184 
185 	if (dst->sin_family != sin_dst->sin_family ||
186 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
187 		/* cache route doesn't match */
188 		dst->sin_family = sin_dst->sin_family;
189 		dst->sin_len = sizeof(struct sockaddr_in);
190 		dst->sin_addr = sin_dst->sin_addr;
191 		if (ro->ro_rt != NULL) {
192 			RTFREE(ro->ro_rt);
193 			ro->ro_rt = NULL;
194 		}
195 #if 0
196 		sc->gif_if.if_mtu = GIF_MTU;
197 #endif
198 	}
199 
200 	if (ro->ro_rt == NULL) {
201 		rtalloc(ro);
202 		if (ro->ro_rt == NULL) {
203 			m_freem(m);
204 			return ENETUNREACH;
205 		}
206 
207 		/* if it constitutes infinite encapsulation, punt. */
208 		if (ro->ro_rt->rt_ifp == ifp) {
209 			m_freem(m);
210 			return ENETUNREACH;	/* XXX */
211 		}
212 #if 0
213 		ifp->if_mtu = ro->ro_rt->rt_ifp->if_mtu - sizeof(struct ip);
214 #endif
215 	}
216 
217 	error = ip_output(m, NULL, ro, 0, NULL, NULL);
218 	return(error);
219 }
220 
221 int
222 in_gif_input(struct mbuf **mp, int *offp, int proto)
223 {
224 	struct mbuf *m = *mp;
225 	struct ifnet *gifp = NULL;
226 	struct ip *ip;
227 	int af;
228 	u_int8_t otos;
229 	int off;
230 
231 	off = *offp;
232 	*mp = NULL;
233 
234 	ip = mtod(m, struct ip *);
235 
236 	gifp = (struct ifnet *)encap_getarg(m);
237 
238 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
239 		m_freem(m);
240 		ipstat.ips_nogif++;
241 		return(IPPROTO_DONE);
242 	}
243 
244 	otos = ip->ip_tos;
245 	m_adj(m, off);
246 
247 	switch (proto) {
248 #ifdef INET
249 	case IPPROTO_IPV4:
250 	    {
251 		struct ip *ip;
252 		af = AF_INET;
253 		if (m->m_len < sizeof *ip) {
254 			m = m_pullup(m, sizeof *ip);
255 			if (!m)
256 				return(IPPROTO_DONE);
257 		}
258 		ip = mtod(m, struct ip *);
259 		if (gifp->if_flags & IFF_LINK1)
260 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
261 		else
262 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
263 		break;
264 	    }
265 #endif
266 #ifdef INET6
267 	case IPPROTO_IPV6:
268 	    {
269 		struct ip6_hdr *ip6;
270 		u_int8_t itos;
271 		af = AF_INET6;
272 		if (m->m_len < sizeof *ip6) {
273 			m = m_pullup(m, sizeof *ip6);
274 			if (!m)
275 				return(IPPROTO_DONE);
276 		}
277 		ip6 = mtod(m, struct ip6_hdr *);
278 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
279 		if (gifp->if_flags & IFF_LINK1)
280 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
281 		else
282 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
283 		ip6->ip6_flow &= ~htonl(0xff << 20);
284 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
285 		break;
286 	    }
287 #endif /* INET6 */
288 	default:
289 		ipstat.ips_nogif++;
290 		m_freem(m);
291 		return(IPPROTO_DONE);
292 	}
293 	gif_input(m, af, gifp);
294 	return(IPPROTO_DONE);
295 }
296 
297 /*
298  * validate outer address.
299  */
300 static int
301 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
302 {
303 	struct sockaddr_in *src, *dst;
304 	struct in_ifaddr_container *iac;
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 	TAILQ_FOREACH(iac, &in_ifaddrheads[mycpuid], ia_link) {
323 		struct in_ifaddr *ia4 = iac->ia;
324 
325 		if (!(ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST))
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) && ifp != NULL) {
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 = rtpurelookup((struct sockaddr *)&sin);
341 		if (rt != NULL)
342 			--rt->rt_refcnt;
343 		if (rt == NULL || rt->rt_ifp != ifp) {
344 #if 0
345 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
346 			    "due to ingress filter\n", if_name(&sc->gif_if),
347 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
348 #endif
349 			return 0;
350 		}
351 	}
352 
353 	return 32 * 2;
354 }
355 
356 /*
357  * we know that we are in IFF_UP, outer address available, and outer family
358  * matched the physical addr family.  see gif_encapcheck().
359  */
360 int
361 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
362 {
363 	struct ip ip;
364 	struct gif_softc *sc;
365 	struct ifnet *ifp;
366 
367 	/* sanity check done in caller */
368 	sc = (struct gif_softc *)arg;
369 
370 	/* LINTED const cast */
371 	m_copydata(__DECONST(struct mbuf *, m), 0, sizeof ip, (caddr_t)&ip);
372 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
373 
374 	return gif_validate4(&ip, sc, ifp);
375 }
376 
377 int
378 in_gif_attach(struct gif_softc *sc)
379 {
380 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
381 	    &in_gif_protosw, sc);
382 	if (sc->encap_cookie4 == NULL)
383 		return EEXIST;
384 	return 0;
385 }
386 
387 int
388 in_gif_detach(struct gif_softc *sc)
389 {
390 	int error;
391 
392 	error = encap_detach(sc->encap_cookie4);
393 	if (error == 0)
394 		sc->encap_cookie4 = NULL;
395 	return error;
396 }
397 
398 #endif /* INET */
399