in_gif.c revision 274225 
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: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/sys/netinet/in_gif.c 274225 2014-11-07 09:39:05Z glebius $");
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/sysctl.h>
48#include <sys/protosw.h>
49#include <sys/malloc.h>
50
51#include <net/if.h>
52#include <net/if_var.h>
53#include <net/route.h>
54#include <net/vnet.h>
55
56#include <netinet/in.h>
57#include <netinet/in_systm.h>
58#include <netinet/ip.h>
59#include <netinet/ip_var.h>
60#include <netinet/in_gif.h>
61#include <netinet/in_var.h>
62#include <netinet/ip_encap.h>
63#include <netinet/ip_ecn.h>
64
65#ifdef INET6
66#include <netinet/ip6.h>
67#endif
68
69#include <net/if_gif.h>
70
71static int gif_validate4(const struct ip *, struct gif_softc *,
72	struct ifnet *);
73
74extern  struct domain inetdomain;
75struct protosw in_gif_protosw = {
76	.pr_type =		SOCK_RAW,
77	.pr_domain =		&inetdomain,
78	.pr_protocol =		0/* IPPROTO_IPV[46] */,
79	.pr_flags =		PR_ATOMIC|PR_ADDR,
80	.pr_input =		in_gif_input,
81	.pr_output =		rip_output,
82	.pr_ctloutput =		rip_ctloutput,
83	.pr_usrreqs =		&rip_usrreqs
84};
85
86VNET_DEFINE(int, ip_gif_ttl) = GIF_TTL;
87#define	V_ip_gif_ttl		VNET(ip_gif_ttl)
88SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW,
89	&VNET_NAME(ip_gif_ttl), 0, "");
90
91int
92in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
93{
94	GIF_RLOCK_TRACKER;
95	struct gif_softc *sc = ifp->if_softc;
96	struct ip *ip;
97	int len;
98
99	/* prepend new IP header */
100	len = sizeof(struct ip);
101#ifndef __NO_STRICT_ALIGNMENT
102	if (proto == IPPROTO_ETHERIP)
103		len += ETHERIP_ALIGN;
104#endif
105	M_PREPEND(m, len, M_NOWAIT);
106	if (m == NULL)
107		return (ENOBUFS);
108#ifndef __NO_STRICT_ALIGNMENT
109	if (proto == IPPROTO_ETHERIP) {
110		len = mtod(m, vm_offset_t) & 3;
111		KASSERT(len == 0 || len == ETHERIP_ALIGN,
112		    ("in_gif_output: unexpected misalignment"));
113		m->m_data += len;
114		m->m_len -= ETHERIP_ALIGN;
115	}
116#endif
117	ip = mtod(m, struct ip *);
118	GIF_RLOCK(sc);
119	if (sc->gif_family != AF_INET) {
120		m_freem(m);
121		GIF_RUNLOCK(sc);
122		return (ENETDOWN);
123	}
124	bcopy(sc->gif_iphdr, ip, sizeof(struct ip));
125	GIF_RUNLOCK(sc);
126
127	ip->ip_p = proto;
128	/* version will be set in ip_output() */
129	ip->ip_ttl = V_ip_gif_ttl;
130	ip->ip_len = htons(m->m_pkthdr.len);
131	ip->ip_tos = ecn;
132
133	return (ip_output(m, NULL, NULL, 0, NULL, NULL));
134}
135
136int
137in_gif_input(struct mbuf **mp, int *offp, int proto)
138{
139	struct mbuf *m = *mp;
140	struct gif_softc *sc;
141	struct ifnet *gifp;
142	struct ip *ip;
143	uint8_t ecn;
144
145	sc = encap_getarg(m);
146	if (sc == NULL) {
147		m_freem(m);
148		KMOD_IPSTAT_INC(ips_nogif);
149		return (IPPROTO_DONE);
150	}
151	gifp = GIF2IFP(sc);
152	if ((gifp->if_flags & IFF_UP) != 0) {
153		ip = mtod(m, struct ip *);
154		ecn = ip->ip_tos;
155		m_adj(m, *offp);
156		gif_input(m, gifp, proto, ecn);
157	} else {
158		m_freem(m);
159		KMOD_IPSTAT_INC(ips_nogif);
160	}
161	return (IPPROTO_DONE);
162}
163
164/*
165 * validate outer address.
166 */
167static int
168gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
169{
170
171	GIF_RLOCK_ASSERT(sc);
172
173	/* check for address match */
174	if (sc->gif_iphdr->ip_src.s_addr != ip->ip_dst.s_addr ||
175	    sc->gif_iphdr->ip_dst.s_addr != ip->ip_src.s_addr)
176		return (0);
177
178	/* martian filters on outer source - NOT done in ip_input! */
179	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
180		return (0);
181	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
182	case 0:
183	case 127:
184	case 255:
185		return (0);
186	}
187
188	/* ingress filters on outer source */
189	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
190		struct sockaddr_in sin;
191		struct rtentry *rt;
192
193		bzero(&sin, sizeof(sin));
194		sin.sin_family = AF_INET;
195		sin.sin_len = sizeof(struct sockaddr_in);
196		sin.sin_addr = ip->ip_src;
197		/* XXX MRT  check for the interface we would use on output */
198		rt = in_rtalloc1((struct sockaddr *)&sin, 0,
199		    0UL, sc->gif_fibnum);
200		if (!rt || rt->rt_ifp != ifp) {
201			if (rt)
202				RTFREE_LOCKED(rt);
203			return (0);
204		}
205		RTFREE_LOCKED(rt);
206	}
207	return (32 * 2);
208}
209
210/*
211 * we know that we are in IFF_UP, outer address available, and outer family
212 * matched the physical addr family.  see gif_encapcheck().
213 */
214int
215in_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
216{
217	struct ip ip;
218	struct gif_softc *sc;
219	struct ifnet *ifp;
220
221	/* sanity check done in caller */
222	sc = (struct gif_softc *)arg;
223	GIF_RLOCK_ASSERT(sc);
224
225	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
226	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
227	return (gif_validate4(&ip, sc, ifp));
228}
229
230int
231in_gif_attach(struct gif_softc *sc)
232{
233
234	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
235	sc->gif_ecookie = encap_attach_func(AF_INET, -1, gif_encapcheck,
236	    &in_gif_protosw, sc);
237	if (sc->gif_ecookie == NULL)
238		return (EEXIST);
239	return (0);
240}
241