xref: /freebsd/sys/netinet/in_gif.c (revision 56ca39961bd1c9946a505c41c3fc634ef63fdd42) 
1 /*
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 /*
33  * in_gif.c
34  */
35 
36 #include "opt_mrouting.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 <net/if.h>
50 #include <net/route.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #include <netinet/ip.h>
55 #ifdef INET6
56 #include <netinet/ip6.h>
57 #endif
58 #include <netinet/ip_var.h>
59 #include <netinet/in_gif.h>
60 #include <netinet/ip_ecn.h>
61 #ifdef INET6
62 #include <netinet6/ip6_ecn.h>
63 #endif
64 
65 #ifdef MROUTING
66 #include <netinet/ip_mroute.h>
67 #endif /* MROUTING */
68 
69 #include <net/if_gif.h>
70 
71 #include "gif.h"
72 
73 #include <machine/stdarg.h>
74 
75 #include <net/net_osdep.h>
76 
77 #if NGIF > 0
78 int ip_gif_ttl = GIF_TTL;
79 #else
80 int ip_gif_ttl = 0;
81 #endif
82 
83 SYSCTL_DECL(_net_inet_ip);
84 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
85 	&ip_gif_ttl,	0, "");
86 
87 #define IN6_IS_ADDR_6TO4(x)	(ntohs((x)->s6_addr16[0]) == 0x2002)
88 #define GET_V4(x)	((struct in_addr *)(&(x)->s6_addr16[1]))
89 
90 int
91 in_gif_output(ifp, family, m, rt)
92 	struct ifnet	*ifp;
93 	int		family;
94 	struct mbuf	*m;
95 	struct rtentry *rt;
96 {
97 	register struct gif_softc *sc = (struct gif_softc*)ifp;
98 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
99 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
100 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
101 	struct ip iphdr;	/* capsule IP header, host byte ordered */
102 	int proto, error;
103 	u_int8_t tos;
104 #ifdef INET6
105 	struct ip6_hdr *ip6 = NULL;
106 #endif
107 
108 	if (sin_src == NULL || sin_dst == NULL ||
109 	    sin_src->sin_family != AF_INET ||
110 	    sin_dst->sin_family != AF_INET) {
111 		m_freem(m);
112 		return EAFNOSUPPORT;
113 	}
114 
115 	switch (family) {
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 #ifdef INET6
131 	case AF_INET6:
132 	    {
133 		proto = IPPROTO_IPV6;
134 		if (m->m_len < sizeof(*ip6)) {
135 			m = m_pullup(m, sizeof(*ip6));
136 			if (!m)
137 				return ENOBUFS;
138 		}
139 		ip6 = mtod(m, struct ip6_hdr *);
140 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
141 		break;
142 	    }
143 #endif /*INET6*/
144 	default:
145 #ifdef DIAGNOSTIC
146 		printf("in_gif_output: warning: unknown family %d passed\n",
147 			family);
148 #endif
149 		m_freem(m);
150 		return EAFNOSUPPORT;
151 	}
152 
153 	bzero(&iphdr, sizeof(iphdr));
154 	iphdr.ip_src = sin_src->sin_addr;
155 #ifdef INET6
156 	/* XXX: temporal stf support hack */
157 	if (bcmp(ifp->if_name, "stf", 3) == 0) {
158 		if (ip6 == NULL) {
159 			m_freem(m);
160 			return ENETUNREACH;
161 		}
162 		if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
163 			iphdr.ip_dst = *GET_V4(&ip6->ip6_dst);
164 		else if (rt && rt->rt_gateway->sa_family == AF_INET6) {
165 			struct in6_addr *dst6;
166 
167 			dst6 = &((struct sockaddr_in6 *)
168 				 (rt->rt_gateway))->sin6_addr;
169 			if (IN6_IS_ADDR_6TO4(dst6))
170 				iphdr.ip_dst = *GET_V4(dst6);
171 			else {
172 				m_freem(m);
173 				return ENETUNREACH;
174 			}
175 		} else {
176 			m_freem(m);
177 			return ENETUNREACH;
178 		}
179 	} else
180 #endif
181 	if (ifp->if_flags & IFF_LINK0) {
182 		/* multi-destination mode */
183 		if (sin_dst->sin_addr.s_addr != INADDR_ANY)
184 			iphdr.ip_dst = sin_dst->sin_addr;
185 		else if (rt) {
186 			iphdr.ip_dst = ((struct sockaddr_in *)
187 					(rt->rt_gateway))->sin_addr;
188 		} else {
189 			m_freem(m);
190 			return ENETUNREACH;
191 		}
192 	} else {
193 		/* bidirectional configured tunnel mode */
194 		if (sin_dst->sin_addr.s_addr != INADDR_ANY)
195 			iphdr.ip_dst = sin_dst->sin_addr;
196 		else {
197 			m_freem(m);
198 			return ENETUNREACH;
199 		}
200 	}
201 	iphdr.ip_p = proto;
202 	/* version will be set in ip_output() */
203 	iphdr.ip_ttl = ip_gif_ttl;
204 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
205 	if (ifp->if_flags & IFF_LINK1)
206 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
207 
208 	/* prepend new IP header */
209 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
210 	if (m && m->m_len < sizeof(struct ip))
211 		m = m_pullup(m, sizeof(struct ip));
212 	if (m == NULL) {
213 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
214 		return ENOBUFS;
215 	}
216 
217 	*(mtod(m, struct ip *)) = iphdr;
218 
219 	if (dst->sin_family != sin_dst->sin_family ||
220 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
221 		/* cache route doesn't match */
222 		dst->sin_family = sin_dst->sin_family;
223 		dst->sin_len = sizeof(struct sockaddr_in);
224 		dst->sin_addr = sin_dst->sin_addr;
225 		if (sc->gif_ro.ro_rt) {
226 			RTFREE(sc->gif_ro.ro_rt);
227 			sc->gif_ro.ro_rt = NULL;
228 		}
229 	}
230 
231 	if (sc->gif_ro.ro_rt == NULL) {
232 		rtalloc(&sc->gif_ro);
233 		if (sc->gif_ro.ro_rt == NULL) {
234 			m_freem(m);
235 			return ENETUNREACH;
236 		}
237 	}
238 
239 	error = ip_output(m, 0, &sc->gif_ro, 0, 0);
240 	return(error);
241 }
242 
243 void
244 in_gif_input(struct mbuf *m, int off, int proto)
245 {
246 	struct gif_softc *sc;
247 	struct ifnet *gifp = NULL;
248 	struct ip *ip;
249 	int i, af;
250 	u_int8_t otos;
251 
252 	ip = mtod(m, struct ip *);
253 
254 	/* this code will be soon improved. */
255 #define	satosin(sa)	((struct sockaddr_in *)(sa))
256 	for (i = 0, sc = gif; i < ngif; i++, sc++) {
257 		if (sc->gif_psrc == NULL
258 		 || sc->gif_pdst == NULL
259 		 || sc->gif_psrc->sa_family != AF_INET
260 		 || sc->gif_pdst->sa_family != AF_INET) {
261 			continue;
262 		}
263 
264 		if ((sc->gif_if.if_flags & IFF_UP) == 0)
265 			continue;
266 
267 #ifdef INET6
268 		/* XXX: temporal stf support hack */
269 		if (proto == IPPROTO_IPV6 &&
270 		    bcmp(sc->gif_if.if_name, "stf", 3) == 0 &&
271 		    (satosin(sc->gif_psrc)->sin_addr.s_addr ==
272 		     ip->ip_dst.s_addr ||
273 		     IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) &&
274 		    satosin(sc->gif_pdst)->sin_addr.s_addr ==
275 		    INADDR_BROADCAST) {
276 			gifp = &sc->gif_if;
277 			break;
278 		}
279 #endif
280 
281 		if ((sc->gif_if.if_flags & IFF_LINK0)
282 		 && satosin(sc->gif_psrc)->sin_addr.s_addr == ip->ip_dst.s_addr
283 		 && satosin(sc->gif_pdst)->sin_addr.s_addr == INADDR_ANY) {
284 			gifp = &sc->gif_if;
285 			continue;
286 		}
287 
288 		if (satosin(sc->gif_psrc)->sin_addr.s_addr == ip->ip_dst.s_addr
289 		 && satosin(sc->gif_pdst)->sin_addr.s_addr == ip->ip_src.s_addr)
290 		{
291 			gifp = &sc->gif_if;
292 			break;
293 		}
294 	}
295 
296 	if (gifp == NULL) {
297 #ifdef MROUTING
298 		/* for backward compatibility */
299 		if (proto == IPPROTO_IPV4) {
300 			ipip_input(m, off, proto);
301 			return;
302 		}
303 #endif /*MROUTING*/
304 		m_freem(m);
305 		ipstat.ips_nogif++;
306 		return;
307 	}
308 
309 	otos = ip->ip_tos;
310 	m_adj(m, off);
311 
312 	switch (proto) {
313 	case IPPROTO_IPV4:
314 	    {
315 		struct ip *ip;
316 
317 #ifdef INET6
318 		if (bcmp(gifp->if_name, "stf", 3) == 0) {
319 			m_freem(m);
320 			return;
321 		}
322 #endif
323 		af = AF_INET;
324 		if (m->m_len < sizeof(*ip)) {
325 			m = m_pullup(m, sizeof(*ip));
326 			if (!m)
327 				return;
328 		}
329 		ip = mtod(m, struct ip *);
330 		if (gifp->if_flags & IFF_LINK1)
331 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
332 		break;
333 	    }
334 #ifdef INET6
335 	case IPPROTO_IPV6:
336 	    {
337 		struct ip6_hdr *ip6;
338 		u_int8_t itos;
339 		af = AF_INET6;
340 		if (m->m_len < sizeof(*ip6)) {
341 			m = m_pullup(m, sizeof(*ip6));
342 			if (!m)
343 				return;
344 		}
345 		ip6 = mtod(m, struct ip6_hdr *);
346 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
347 		if (gifp->if_flags & IFF_LINK1)
348 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
349 		ip6->ip6_flow &= ~htonl(0xff << 20);
350 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
351 		break;
352 	    }
353 #endif /* INET6 */
354 	default:
355 		ipstat.ips_nogif++;
356 		m_freem(m);
357 		return;
358 	}
359 	gif_input(m, af, gifp);
360 	return;
361 }
362