xref: /dragonfly/sys/netinet/in_gif.c (revision 556932ec) 
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 #ifdef INET
71 static int gif_validate4 (const struct ip *, struct gif_softc *,
72 			  struct ifnet *);
73 
74 extern  struct domain inetdomain;
75 const struct protosw in_gif_protosw =
76     {
77 	.pr_type = SOCK_RAW,
78 	.pr_domain = &inetdomain,
79 	.pr_protocol = 0 /*IPPROTO_IPV[46]*/,
80 	.pr_flags = PR_ATOMIC|PR_ADDR,
81 
82 	.pr_input = in_gif_input,
83 	.pr_output = rip_output,
84 	.pr_ctlinput = NULL,
85 	.pr_ctloutput = rip_ctloutput,
86 
87 	.pr_ctlport = NULL,
88 	.pr_usrreqs = &rip_usrreqs
89     };
90 
91 int ip_gif_ttl = GIF_TTL;
92 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
93 	&ip_gif_ttl, 0, "TTL of GIF packet");
94 
95 int
96 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
97 {
98 	struct gif_softc *sc = (struct gif_softc*)ifp;
99 	struct route *ro = &sc->gif_ro[mycpu->gd_cpuid];
100 	struct sockaddr_in *dst = (struct sockaddr_in *)&ro->ro_dst;
101 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
102 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
103 	struct ip iphdr;	/* capsule IP header, host byte ordered */
104 	int proto, error;
105 	u_int8_t tos;
106 
107 	if (sin_src == NULL || sin_dst == NULL ||
108 	    sin_src->sin_family != AF_INET ||
109 	    sin_dst->sin_family != AF_INET) {
110 		m_freem(m);
111 		return EAFNOSUPPORT;
112 	}
113 
114 	switch (family) {
115 #ifdef INET
116 	case AF_INET:
117 	    {
118 		struct ip *ip;
119 
120 		proto = IPPROTO_IPV4;
121 		if (m->m_len < sizeof *ip) {
122 			m = m_pullup(m, sizeof *ip);
123 			if (!m)
124 				return ENOBUFS;
125 		}
126 		ip = mtod(m, struct ip *);
127 		tos = ip->ip_tos;
128 		break;
129 	    }
130 #endif
131 #ifdef INET6
132 	case AF_INET6:
133 	    {
134 		struct ip6_hdr *ip6;
135 		proto = IPPROTO_IPV6;
136 		if (m->m_len < sizeof *ip6) {
137 			m = m_pullup(m, sizeof *ip6);
138 			if (!m)
139 				return ENOBUFS;
140 		}
141 		ip6 = mtod(m, struct ip6_hdr *);
142 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
143 		break;
144 	    }
145 #endif
146 	default:
147 #ifdef DEBUG
148 		kprintf("in_gif_output: warning: unknown family %d passed\n",
149 			family);
150 #endif
151 		m_freem(m);
152 		return EAFNOSUPPORT;
153 	}
154 
155 	bzero(&iphdr, sizeof iphdr);
156 	iphdr.ip_src = sin_src->sin_addr;
157 	/* bidirectional configured tunnel mode */
158 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
159 		iphdr.ip_dst = sin_dst->sin_addr;
160 	else {
161 		m_freem(m);
162 		return ENETUNREACH;
163 	}
164 	iphdr.ip_p = proto;
165 	/* version will be set in ip_output() */
166 	iphdr.ip_ttl = ip_gif_ttl;
167 	iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
168 	if (ifp->if_flags & IFF_LINK1)
169 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
170 	else
171 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
172 
173 	/* prepend new IP header */
174 	M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
175 	if (m && m->m_len < sizeof(struct ip))
176 		m = m_pullup(m, sizeof(struct ip));
177 	if (m == NULL) {
178 		kprintf("ENOBUFS in in_gif_output %d\n", __LINE__);
179 		return ENOBUFS;
180 	}
181 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
182 
183 	if (dst->sin_family != sin_dst->sin_family ||
184 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
185 		/* cache route doesn't match */
186 		dst->sin_family = sin_dst->sin_family;
187 		dst->sin_len = sizeof(struct sockaddr_in);
188 		dst->sin_addr = sin_dst->sin_addr;
189 		if (ro->ro_rt != NULL) {
190 			RTFREE(ro->ro_rt);
191 			ro->ro_rt = NULL;
192 		}
193 #if 0
194 		sc->gif_if.if_mtu = GIF_MTU;
195 #endif
196 	}
197 
198 	if (ro->ro_rt == NULL) {
199 		rtalloc(ro);
200 		if (ro->ro_rt == NULL) {
201 			m_freem(m);
202 			return ENETUNREACH;
203 		}
204 
205 		/* if it constitutes infinite encapsulation, punt. */
206 		if (ro->ro_rt->rt_ifp == ifp) {
207 			m_freem(m);
208 			return ENETUNREACH;	/* XXX */
209 		}
210 #if 0
211 		ifp->if_mtu = ro->ro_rt->rt_ifp->if_mtu - sizeof(struct ip);
212 #endif
213 	}
214 
215 	error = ip_output(m, NULL, ro, 0, NULL, NULL);
216 	return(error);
217 }
218 
219 int
220 in_gif_input(struct mbuf **mp, int *offp, int proto)
221 {
222 	struct mbuf *m = *mp;
223 	struct ifnet *gifp = NULL;
224 	struct ip *ip;
225 	int af;
226 	u_int8_t otos;
227 	int off;
228 
229 	off = *offp;
230 	*mp = NULL;
231 
232 	ip = mtod(m, struct ip *);
233 
234 	gifp = (struct ifnet *)encap_getarg(m);
235 
236 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
237 		m_freem(m);
238 		ipstat.ips_nogif++;
239 		return(IPPROTO_DONE);
240 	}
241 
242 	otos = ip->ip_tos;
243 	m_adj(m, off);
244 
245 	switch (proto) {
246 #ifdef INET
247 	case IPPROTO_IPV4:
248 	    {
249 		struct ip *ip;
250 		af = AF_INET;
251 		if (m->m_len < sizeof *ip) {
252 			m = m_pullup(m, sizeof *ip);
253 			if (!m)
254 				return(IPPROTO_DONE);
255 		}
256 		ip = mtod(m, struct ip *);
257 		if (gifp->if_flags & IFF_LINK1)
258 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
259 		else
260 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
261 		break;
262 	    }
263 #endif
264 #ifdef INET6
265 	case IPPROTO_IPV6:
266 	    {
267 		struct ip6_hdr *ip6;
268 		u_int8_t itos;
269 		af = AF_INET6;
270 		if (m->m_len < sizeof *ip6) {
271 			m = m_pullup(m, sizeof *ip6);
272 			if (!m)
273 				return(IPPROTO_DONE);
274 		}
275 		ip6 = mtod(m, struct ip6_hdr *);
276 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
277 		if (gifp->if_flags & IFF_LINK1)
278 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
279 		else
280 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
281 		ip6->ip6_flow &= ~htonl(0xff << 20);
282 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
283 		break;
284 	    }
285 #endif /* INET6 */
286 	default:
287 		ipstat.ips_nogif++;
288 		m_freem(m);
289 		return(IPPROTO_DONE);
290 	}
291 	gif_input(m, af, gifp);
292 	return(IPPROTO_DONE);
293 }
294 
295 /*
296  * validate outer address.
297  */
298 static int
299 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
300 {
301 	struct sockaddr_in *src, *dst;
302 	struct in_ifaddr_container *iac;
303 
304 	src = (struct sockaddr_in *)sc->gif_psrc;
305 	dst = (struct sockaddr_in *)sc->gif_pdst;
306 
307 	/* check for address match */
308 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
309 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
310 		return 0;
311 
312 	/* martian filters on outer source - NOT done in ip_input! */
313 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
314 		return 0;
315 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
316 	case 0: case 127: case 255:
317 		return 0;
318 	}
319 	/* reject packets with broadcast on source */
320 	TAILQ_FOREACH(iac, &in_ifaddrheads[mycpuid], ia_link) {
321 		struct in_ifaddr *ia4 = iac->ia;
322 
323 		if (!(ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST))
324 			continue;
325 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
326 			return 0;
327 	}
328 
329 	/* ingress filters on outer source */
330 	if (!(sc->gif_if.if_flags & IFF_LINK2) && ifp != NULL) {
331 		struct sockaddr_in sin;
332 		struct rtentry *rt;
333 
334 		bzero(&sin, sizeof sin);
335 		sin.sin_family = AF_INET;
336 		sin.sin_len = sizeof(struct sockaddr_in);
337 		sin.sin_addr = ip->ip_src;
338 		rt = rtpurelookup((struct sockaddr *)&sin);
339 		if (rt != NULL)
340 			--rt->rt_refcnt;
341 		if (rt == NULL || 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 			return 0;
348 		}
349 	}
350 
351 	return 32 * 2;
352 }
353 
354 /*
355  * we know that we are in IFF_UP, outer address available, and outer family
356  * matched the physical addr family.  see gif_encapcheck().
357  */
358 int
359 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
360 {
361 	struct ip ip;
362 	struct gif_softc *sc;
363 	struct ifnet *ifp;
364 
365 	/* sanity check done in caller */
366 	sc = (struct gif_softc *)arg;
367 
368 	/* LINTED const cast */
369 	m_copydata(__DECONST(struct mbuf *, m), 0, sizeof ip, (caddr_t)&ip);
370 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
371 
372 	return gif_validate4(&ip, sc, ifp);
373 }
374 
375 int
376 in_gif_attach(struct gif_softc *sc)
377 {
378 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
379 	    &in_gif_protosw, sc);
380 	if (sc->encap_cookie4 == NULL)
381 		return EEXIST;
382 	return 0;
383 }
384 
385 int
386 in_gif_detach(struct gif_softc *sc)
387 {
388 	int error;
389 
390 	error = encap_detach(sc->encap_cookie4);
391 	if (error == 0)
392 		sc->encap_cookie4 = NULL;
393 	return error;
394 }
395 
396 #endif /* INET */
397