1/*-
2 * Copyright (c) 1998 The NetBSD Foundation, Inc.
3 * Copyright (c) 2014 Andrey V. Elsukov <ae@FreeBSD.org>
4 * All rights reserved.
5 *
6 * This code is derived from software contributed to The NetBSD Foundation
7 * by Heiko W.Rupp <hwr@pilhuhn.de>
8 *
9 * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 *
32 * $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include "opt_inet.h"
39#include "opt_inet6.h"
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/mbuf.h>
44#include <sys/socket.h>
45#include <sys/socketvar.h>
46#include <sys/protosw.h>
47#include <sys/errno.h>
48#include <sys/time.h>
49#include <sys/kernel.h>
50#include <sys/lock.h>
51#include <sys/rmlock.h>
52#include <sys/sysctl.h>
53#include <net/ethernet.h>
54#include <net/if.h>
55#include <net/if_var.h>
56#include <net/vnet.h>
57
58#include <netinet/in.h>
59#include <netinet/in_var.h>
60#include <netinet/ip.h>
61#include <netinet/ip_encap.h>
62#include <netinet/ip_var.h>
63
64#ifdef INET6
65#include <netinet/ip6.h>
66#endif
67
68#include <net/if_gre.h>
69
70extern struct domain inetdomain;
71static const struct protosw in_gre_protosw = {
72	.pr_type =		SOCK_RAW,
73	.pr_domain =		&inetdomain,
74	.pr_protocol =		IPPROTO_GRE,
75	.pr_flags =		PR_ATOMIC|PR_ADDR,
76	.pr_input =		gre_input,
77	.pr_output =		rip_output,
78	.pr_ctlinput =		rip_ctlinput,
79	.pr_ctloutput =		rip_ctloutput,
80	.pr_usrreqs =		&rip_usrreqs
81};
82
83#define	GRE_TTL			30
84VNET_DEFINE(int, ip_gre_ttl) = GRE_TTL;
85#define	V_ip_gre_ttl		VNET(ip_gre_ttl)
86SYSCTL_INT(_net_inet_ip, OID_AUTO, grettl, CTLFLAG_VNET | CTLFLAG_RW,
87	&VNET_NAME(ip_gre_ttl), 0, "");
88
89static int
90in_gre_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
91{
92	GRE_RLOCK_TRACKER;
93	struct gre_softc *sc;
94	struct ip *ip;
95
96	sc = (struct gre_softc *)arg;
97	if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0)
98		return (0);
99
100	M_ASSERTPKTHDR(m);
101	/*
102	 * We expect that payload contains at least IPv4
103	 * or IPv6 packet.
104	 */
105	if (m->m_pkthdr.len < sizeof(struct greip) + sizeof(struct ip))
106		return (0);
107
108	GRE_RLOCK(sc);
109	if (sc->gre_family == 0)
110		goto bad;
111
112	KASSERT(sc->gre_family == AF_INET,
113	    ("wrong gre_family: %d", sc->gre_family));
114
115	ip = mtod(m, struct ip *);
116	if (sc->gre_oip.ip_src.s_addr != ip->ip_dst.s_addr ||
117	    sc->gre_oip.ip_dst.s_addr != ip->ip_src.s_addr)
118		goto bad;
119
120	GRE_RUNLOCK(sc);
121	return (32 * 2);
122bad:
123	GRE_RUNLOCK(sc);
124	return (0);
125}
126
127int
128in_gre_output(struct mbuf *m, int af, int hlen)
129{
130	struct greip *gi;
131
132	gi = mtod(m, struct greip *);
133	switch (af) {
134	case AF_INET:
135		/*
136		 * gre_transmit() has used M_PREPEND() that doesn't guarantee
137		 * m_data is contiguous more than hlen bytes. Use m_copydata()
138		 * here to avoid m_pullup().
139		 */
140		m_copydata(m, hlen + offsetof(struct ip, ip_tos),
141		    sizeof(u_char), &gi->gi_ip.ip_tos);
142		m_copydata(m, hlen + offsetof(struct ip, ip_id),
143		    sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id);
144		break;
145#ifdef INET6
146	case AF_INET6:
147		gi->gi_ip.ip_tos = 0; /* XXX */
148		ip_fillid(&gi->gi_ip);
149		break;
150#endif
151	}
152	gi->gi_ip.ip_ttl = V_ip_gre_ttl;
153	gi->gi_ip.ip_len = htons(m->m_pkthdr.len);
154	return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL));
155}
156
157int
158in_gre_attach(struct gre_softc *sc)
159{
160
161	KASSERT(sc->gre_ecookie == NULL, ("gre_ecookie isn't NULL"));
162	sc->gre_ecookie = encap_attach_func(AF_INET, IPPROTO_GRE,
163	    in_gre_encapcheck, &in_gre_protosw, sc);
164	if (sc->gre_ecookie == NULL)
165		return (EEXIST);
166	return (0);
167}
168