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 *	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD$");
34
35#include "opt_inet.h"
36#include "opt_inet6.h"
37
38#include <sys/param.h>
39#include <sys/lock.h>
40#include <sys/rmlock.h>
41#include <sys/systm.h>
42#include <sys/socket.h>
43#include <sys/sockio.h>
44#include <sys/mbuf.h>
45#include <sys/errno.h>
46#include <sys/kernel.h>
47#include <sys/queue.h>
48#include <sys/syslog.h>
49#include <sys/sysctl.h>
50#include <sys/protosw.h>
51#include <sys/malloc.h>
52
53#include <net/if.h>
54#include <net/if_var.h>
55#include <net/route.h>
56#include <net/vnet.h>
57
58#include <netinet/in.h>
59#include <netinet/in_systm.h>
60#ifdef INET
61#include <netinet/ip.h>
62#endif
63#include <netinet/ip_encap.h>
64#ifdef INET6
65#include <netinet/ip6.h>
66#include <netinet6/ip6_var.h>
67#include <netinet6/in6_var.h>
68#endif
69#include <netinet6/ip6protosw.h>
70#include <netinet/ip_ecn.h>
71#ifdef INET6
72#include <netinet6/ip6_ecn.h>
73#endif
74
75#include <net/if_gif.h>
76
77#define GIF_HLIM	30
78static VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
79#define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
80
81SYSCTL_DECL(_net_inet6_ip6);
82SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_RW,
83    &VNET_NAME(ip6_gif_hlim), 0, "");
84
85static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
86			 struct ifnet *);
87static int in6_gif_input(struct mbuf **, int *, int);
88
89extern  struct domain inet6domain;
90static struct ip6protosw in6_gif_protosw = {
91	.pr_type =	SOCK_RAW,
92	.pr_domain =	&inet6domain,
93	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
94	.pr_flags =	PR_ATOMIC|PR_ADDR,
95	.pr_input =	in6_gif_input,
96	.pr_output =	rip6_output,
97	.pr_ctloutput =	rip6_ctloutput,
98	.pr_usrreqs =	&rip6_usrreqs
99};
100
101int
102in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
103{
104	GIF_RLOCK_TRACKER;
105	struct gif_softc *sc = ifp->if_softc;
106	struct ip6_hdr *ip6;
107	int len;
108
109	/* prepend new IP header */
110	len = sizeof(struct ip6_hdr);
111#ifndef __NO_STRICT_ALIGNMENT
112	if (proto == IPPROTO_ETHERIP)
113		len += ETHERIP_ALIGN;
114#endif
115	M_PREPEND(m, len, M_NOWAIT);
116	if (m == NULL)
117		return (ENOBUFS);
118#ifndef __NO_STRICT_ALIGNMENT
119	if (proto == IPPROTO_ETHERIP) {
120		len = mtod(m, vm_offset_t) & 3;
121		KASSERT(len == 0 || len == ETHERIP_ALIGN,
122		    ("in6_gif_output: unexpected misalignment"));
123		m->m_data += len;
124		m->m_len -= ETHERIP_ALIGN;
125	}
126#endif
127
128	ip6 = mtod(m, struct ip6_hdr *);
129	GIF_RLOCK(sc);
130	if (sc->gif_family != AF_INET6) {
131		m_freem(m);
132		GIF_RUNLOCK(sc);
133		return (ENETDOWN);
134	}
135	bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
136	GIF_RUNLOCK(sc);
137
138	ip6->ip6_flow  |= htonl((uint32_t)ecn << 20);
139	ip6->ip6_nxt	= proto;
140	ip6->ip6_hlim	= V_ip6_gif_hlim;
141	/*
142	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
143	 * it is too painful to ask for resend of inner packet, to achieve
144	 * path MTU discovery for encapsulated packets.
145	 */
146	return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
147}
148
149static int
150in6_gif_input(struct mbuf **mp, int *offp, int proto)
151{
152	struct mbuf *m = *mp;
153	struct ifnet *gifp;
154	struct gif_softc *sc;
155	struct ip6_hdr *ip6;
156	uint8_t ecn;
157
158	sc = encap_getarg(m);
159	if (sc == NULL) {
160		m_freem(m);
161		IP6STAT_INC(ip6s_nogif);
162		return (IPPROTO_DONE);
163	}
164	gifp = GIF2IFP(sc);
165	if ((gifp->if_flags & IFF_UP) != 0) {
166		ip6 = mtod(m, struct ip6_hdr *);
167		ecn = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
168		m_adj(m, *offp);
169		gif_input(m, gifp, proto, ecn);
170	} else {
171		m_freem(m);
172		IP6STAT_INC(ip6s_nogif);
173	}
174	return (IPPROTO_DONE);
175}
176
177/*
178 * validate outer address.
179 */
180static int
181gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
182    struct ifnet *ifp)
183{
184	int ret;
185
186	GIF_RLOCK_ASSERT(sc);
187	/*
188	 * Check for address match.  Note that the check is for an incoming
189	 * packet.  We should compare the *source* address in our configuration
190	 * and the *destination* address of the packet, and vice versa.
191	 */
192	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, &ip6->ip6_dst))
193		return (0);
194	ret = 128;
195	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, &ip6->ip6_src)) {
196		if ((sc->gif_options & GIF_IGNORE_SOURCE) == 0)
197			return (0);
198	} else
199		ret += 128;
200
201	/* martian filters on outer source - done in ip6_input */
202
203	/* ingress filters on outer source */
204	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
205		struct sockaddr_in6 sin6;
206		struct rtentry *rt;
207
208		bzero(&sin6, sizeof(sin6));
209		sin6.sin6_family = AF_INET6;
210		sin6.sin6_len = sizeof(struct sockaddr_in6);
211		sin6.sin6_addr = ip6->ip6_src;
212		sin6.sin6_scope_id = 0; /* XXX */
213
214		rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL,
215		    sc->gif_fibnum);
216		if (!rt || rt->rt_ifp != ifp) {
217			if (rt)
218				RTFREE_LOCKED(rt);
219			return (0);
220		}
221		RTFREE_LOCKED(rt);
222	}
223
224	return (ret);
225}
226
227/*
228 * we know that we are in IFF_UP, outer address available, and outer family
229 * matched the physical addr family.  see gif_encapcheck().
230 */
231int
232in6_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
233{
234	struct ip6_hdr ip6;
235	struct gif_softc *sc;
236	struct ifnet *ifp;
237
238	/* sanity check done in caller */
239	sc = (struct gif_softc *)arg;
240	GIF_RLOCK_ASSERT(sc);
241
242	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
243	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
244	return (gif_validate6(&ip6, sc, ifp));
245}
246
247int
248in6_gif_attach(struct gif_softc *sc)
249{
250
251	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
252	sc->gif_ecookie = encap_attach_func(AF_INET6, -1, gif_encapcheck,
253	    (void *)&in6_gif_protosw, sc);
254	if (sc->gif_ecookie == NULL)
255		return (EEXIST);
256	return (0);
257}
258