in6_gif.c revision 276149 
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: stable/10/sys/netinet6/in6_gif.c 276149 2014-12-23 16:33:44Z 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 <netinet6/ip6protosw.h>
71#include <netinet/ip_ecn.h>
72#ifdef INET6
73#include <netinet6/ip6_ecn.h>
74#endif
75
76#include <net/if_gif.h>
77
78VNET_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 *);
87
88extern  struct domain inet6domain;
89struct ip6protosw in6_gif_protosw = {
90	.pr_type =	SOCK_RAW,
91	.pr_domain =	&inet6domain,
92	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
93	.pr_flags =	PR_ATOMIC|PR_ADDR,
94	.pr_input =	in6_gif_input,
95	.pr_output =	rip6_output,
96	.pr_ctloutput =	rip6_ctloutput,
97	.pr_usrreqs =	&rip6_usrreqs
98};
99
100int
101in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
102{
103	GIF_RLOCK_TRACKER;
104	struct gif_softc *sc = ifp->if_softc;
105	struct ip6_hdr *ip6;
106	int len;
107
108	/* prepend new IP header */
109	len = sizeof(struct ip6_hdr);
110#ifndef __NO_STRICT_ALIGNMENT
111	if (proto == IPPROTO_ETHERIP)
112		len += ETHERIP_ALIGN;
113#endif
114	M_PREPEND(m, len, M_NOWAIT);
115	if (m == NULL)
116		return (ENOBUFS);
117#ifndef __NO_STRICT_ALIGNMENT
118	if (proto == IPPROTO_ETHERIP) {
119		len = mtod(m, vm_offset_t) & 3;
120		KASSERT(len == 0 || len == ETHERIP_ALIGN,
121		    ("in6_gif_output: unexpected misalignment"));
122		m->m_data += len;
123		m->m_len -= ETHERIP_ALIGN;
124	}
125#endif
126
127	ip6 = mtod(m, struct ip6_hdr *);
128	GIF_RLOCK(sc);
129	if (sc->gif_family != AF_INET6) {
130		m_freem(m);
131		GIF_RUNLOCK(sc);
132		return (ENETDOWN);
133	}
134	bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
135	GIF_RUNLOCK(sc);
136
137	ip6->ip6_flow  |= htonl((uint32_t)ecn << 20);
138	ip6->ip6_nxt	= proto;
139	ip6->ip6_hlim	= V_ip6_gif_hlim;
140	/*
141	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
142	 * it is too painful to ask for resend of inner packet, to achieve
143	 * path MTU discovery for encapsulated packets.
144	 */
145	return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
146}
147
148int
149in6_gif_input(struct mbuf **mp, int *offp, int proto)
150{
151	struct mbuf *m = *mp;
152	struct ifnet *gifp;
153	struct gif_softc *sc;
154	struct ip6_hdr *ip6;
155	uint8_t ecn;
156
157	sc = encap_getarg(m);
158	if (sc == NULL) {
159		m_freem(m);
160		IP6STAT_INC(ip6s_nogif);
161		return (IPPROTO_DONE);
162	}
163	gifp = GIF2IFP(sc);
164	if ((gifp->if_flags & IFF_UP) != 0) {
165		ip6 = mtod(m, struct ip6_hdr *);
166		ecn = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
167		m_adj(m, *offp);
168		gif_input(m, gifp, proto, ecn);
169	} else {
170		m_freem(m);
171		IP6STAT_INC(ip6s_nogif);
172	}
173	return (IPPROTO_DONE);
174}
175
176/*
177 * validate outer address.
178 */
179static int
180gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
181    struct ifnet *ifp)
182{
183
184	GIF_RLOCK_ASSERT(sc);
185	/*
186	 * Check for address match.  Note that the check is for an incoming
187	 * packet.  We should compare the *source* address in our configuration
188	 * and the *destination* address of the packet, and vice versa.
189	 */
190	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, &ip6->ip6_dst) ||
191	    !IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, &ip6->ip6_src))
192		return (0);
193
194	/* martian filters on outer source - done in ip6_input */
195
196	/* ingress filters on outer source */
197	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
198		struct sockaddr_in6 sin6;
199		struct rtentry *rt;
200
201		bzero(&sin6, sizeof(sin6));
202		sin6.sin6_family = AF_INET6;
203		sin6.sin6_len = sizeof(struct sockaddr_in6);
204		sin6.sin6_addr = ip6->ip6_src;
205		sin6.sin6_scope_id = 0; /* XXX */
206
207		rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL,
208		    sc->gif_fibnum);
209		if (!rt || rt->rt_ifp != ifp) {
210			if (rt)
211				RTFREE_LOCKED(rt);
212			return (0);
213		}
214		RTFREE_LOCKED(rt);
215	}
216
217	return (128 * 2);
218}
219
220/*
221 * we know that we are in IFF_UP, outer address available, and outer family
222 * matched the physical addr family.  see gif_encapcheck().
223 */
224int
225in6_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
226{
227	struct ip6_hdr ip6;
228	struct gif_softc *sc;
229	struct ifnet *ifp;
230
231	/* sanity check done in caller */
232	sc = (struct gif_softc *)arg;
233	GIF_RLOCK_ASSERT(sc);
234
235	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
236	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
237	return (gif_validate6(&ip6, sc, ifp));
238}
239
240int
241in6_gif_attach(struct gif_softc *sc)
242{
243
244	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
245	sc->gif_ecookie = encap_attach_func(AF_INET6, -1, gif_encapcheck,
246	    (void *)&in6_gif_protosw, sc);
247	if (sc->gif_ecookie == NULL)
248		return (EEXIST);
249	return (0);
250}
251