in6_gif.c revision 273587 
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: head/sys/netinet6/in6_gif.c 273587 2014-10-24 13:34:22Z ae $");
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_gif.h>
68#include <netinet6/in6_var.h>
69#endif
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
77VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
78#define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
79
80SYSCTL_DECL(_net_inet6_ip6);
81SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_RW,
82    &VNET_NAME(ip6_gif_hlim), 0, "");
83
84static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
85			 struct ifnet *);
86
87extern  struct domain inet6domain;
88struct protosw in6_gif_protosw = {
89	.pr_type =	SOCK_RAW,
90	.pr_domain =	&inet6domain,
91	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
92	.pr_flags =	PR_ATOMIC|PR_ADDR,
93	.pr_input =	in6_gif_input,
94	.pr_output =	rip6_output,
95	.pr_ctloutput =	rip6_ctloutput,
96	.pr_usrreqs =	&rip6_usrreqs
97};
98
99int
100in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
101{
102	GIF_RLOCK_TRACKER;
103	struct gif_softc *sc = ifp->if_softc;
104	struct ip6_hdr *ip6;
105	int len;
106
107	/* prepend new IP header */
108	len = sizeof(struct ip6_hdr);
109#ifndef __NO_STRICT_ALIGNMENT
110	if (proto == IPPROTO_ETHERIP)
111		len += ETHERIP_ALIGN;
112#endif
113	M_PREPEND(m, len, M_NOWAIT);
114	if (m == NULL)
115		return (ENOBUFS);
116#ifndef __NO_STRICT_ALIGNMENT
117	if (proto == IPPROTO_ETHERIP) {
118		len = mtod(m, vm_offset_t) & 3;
119		KASSERT(len == 0 || len == ETHERIP_ALIGN,
120		    ("in6_gif_output: unexpected misalignment"));
121		m->m_data += len;
122		m->m_len -= ETHERIP_ALIGN;
123	}
124#endif
125
126	ip6 = mtod(m, struct ip6_hdr *);
127	GIF_RLOCK(sc);
128	if (sc->gif_family != AF_INET6) {
129		m_freem(m);
130		GIF_RUNLOCK(sc);
131		return (ENETDOWN);
132	}
133	bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
134	GIF_RUNLOCK(sc);
135
136	ip6->ip6_flow  |= htonl((uint32_t)ecn << 20);
137	ip6->ip6_nxt	= proto;
138	ip6->ip6_hlim	= V_ip6_gif_hlim;
139	/*
140	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
141	 * it is too painful to ask for resend of inner packet, to achieve
142	 * path MTU discovery for encapsulated packets.
143	 */
144	return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
145}
146
147int
148in6_gif_input(struct mbuf **mp, int *offp, int proto)
149{
150	struct mbuf *m = *mp;
151	struct ifnet *gifp;
152	struct gif_softc *sc;
153	struct ip6_hdr *ip6;
154	uint8_t ecn;
155
156	sc = encap_getarg(m);
157	if (sc == NULL) {
158		m_freem(m);
159		IP6STAT_INC(ip6s_nogif);
160		return (IPPROTO_DONE);
161	}
162	gifp = GIF2IFP(sc);
163	if ((gifp->if_flags & IFF_UP) != 0) {
164		ip6 = mtod(m, struct ip6_hdr *);
165		ecn = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
166		m_adj(m, *offp);
167		gif_input(m, gifp, proto, ecn);
168	} else {
169		m_freem(m);
170		IP6STAT_INC(ip6s_nogif);
171	}
172	return (IPPROTO_DONE);
173}
174
175/*
176 * validate outer address.
177 */
178static int
179gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
180    struct ifnet *ifp)
181{
182
183	GIF_RLOCK_ASSERT(sc);
184	/*
185	 * Check for address match.  Note that the check is for an incoming
186	 * packet.  We should compare the *source* address in our configuration
187	 * and the *destination* address of the packet, and vice versa.
188	 */
189	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, &ip6->ip6_dst) ||
190	    !IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, &ip6->ip6_src))
191		return (0);
192
193	/* martian filters on outer source - done in ip6_input */
194
195	/* ingress filters on outer source */
196	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
197		struct sockaddr_in6 sin6;
198		struct rtentry *rt;
199
200		bzero(&sin6, sizeof(sin6));
201		sin6.sin6_family = AF_INET6;
202		sin6.sin6_len = sizeof(struct sockaddr_in6);
203		sin6.sin6_addr = ip6->ip6_src;
204		sin6.sin6_scope_id = 0; /* XXX */
205
206		rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL,
207		    sc->gif_fibnum);
208		if (!rt || rt->rt_ifp != ifp) {
209			if (rt)
210				RTFREE_LOCKED(rt);
211			return (0);
212		}
213		RTFREE_LOCKED(rt);
214	}
215
216	return (128 * 2);
217}
218
219/*
220 * we know that we are in IFF_UP, outer address available, and outer family
221 * matched the physical addr family.  see gif_encapcheck().
222 */
223int
224in6_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
225{
226	struct ip6_hdr ip6;
227	struct gif_softc *sc;
228	struct ifnet *ifp;
229
230	/* sanity check done in caller */
231	sc = (struct gif_softc *)arg;
232	GIF_RLOCK_ASSERT(sc);
233
234	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
235	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
236	return (gif_validate6(&ip6, sc, ifp));
237}
238
239int
240in6_gif_attach(struct gif_softc *sc)
241{
242
243	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
244	sc->gif_ecookie = encap_attach_func(AF_INET6, -1, gif_encapcheck,
245	    (void *)&in6_gif_protosw, sc);
246	if (sc->gif_ecookie == NULL)
247		return (EEXIST);
248	return (0);
249}
250