in6_gif.c revision 4736ccfd9c3411d50371d7f21f9450a47c19047e
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 *	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD$");
36
37#include "opt_inet.h"
38#include "opt_inet6.h"
39
40#include <sys/param.h>
41#include <sys/lock.h>
42#include <sys/rmlock.h>
43#include <sys/systm.h>
44#include <sys/socket.h>
45#include <sys/sockio.h>
46#include <sys/mbuf.h>
47#include <sys/errno.h>
48#include <sys/kernel.h>
49#include <sys/queue.h>
50#include <sys/syslog.h>
51#include <sys/sysctl.h>
52#include <sys/protosw.h>
53#include <sys/malloc.h>
54
55#include <net/if.h>
56#include <net/if_var.h>
57#include <net/route.h>
58#include <net/vnet.h>
59
60#include <netinet/in.h>
61#include <netinet/in_systm.h>
62#ifdef INET
63#include <netinet/ip.h>
64#endif
65#include <netinet/ip_encap.h>
66#ifdef INET6
67#include <netinet/ip6.h>
68#include <netinet6/ip6_var.h>
69#include <netinet6/in6_var.h>
70#endif
71#include <netinet/ip_ecn.h>
72#ifdef INET6
73#include <netinet6/ip6_ecn.h>
74#include <netinet6/in6_fib.h>
75#endif
76
77#include <net/if_gif.h>
78
79#define GIF_HLIM	30
80static VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
81#define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
82
83SYSCTL_DECL(_net_inet6_ip6);
84SYSCTL_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_VNET | CTLFLAG_RW,
85    &VNET_NAME(ip6_gif_hlim), 0, "");
86
87static int in6_gif_input(struct mbuf **, int *, int);
88
89extern  struct domain inet6domain;
90static struct protosw 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 * we know that we are in IFF_UP, outer address available, and outer family
179 * matched the physical addr family.  see gif_encapcheck().
180 */
181int
182in6_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
183{
184	const struct ip6_hdr *ip6;
185	struct gif_softc *sc;
186	int ret;
187
188	/* sanity check done in caller */
189	sc = (struct gif_softc *)arg;
190	GIF_RLOCK_ASSERT(sc);
191
192	/*
193	 * Check for address match.  Note that the check is for an incoming
194	 * packet.  We should compare the *source* address in our configuration
195	 * and the *destination* address of the packet, and vice versa.
196	 */
197	ip6 = mtod(m, const struct ip6_hdr *);
198	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, &ip6->ip6_dst))
199		return (0);
200	ret = 128;
201	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, &ip6->ip6_src)) {
202		if ((sc->gif_options & GIF_IGNORE_SOURCE) == 0)
203			return (0);
204	} else
205		ret += 128;
206
207	/* ingress filters on outer source */
208	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
209		struct nhop6_basic nh6;
210
211		/* XXX empty scope id */
212		if (fib6_lookup_nh_basic(sc->gif_fibnum, &ip6->ip6_src, 0, 0, 0,
213		    &nh6) != 0)
214			return (0);
215
216		if (nh6.nh_ifp != m->m_pkthdr.rcvif)
217			return (0);
218	}
219	return (ret);
220}
221
222int
223in6_gif_attach(struct gif_softc *sc)
224{
225
226	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
227	sc->gif_ecookie = encap_attach_func(AF_INET6, -1, gif_encapcheck,
228	    (void *)&in6_gif_protosw, sc);
229	if (sc->gif_ecookie == NULL)
230		return (EEXIST);
231	return (0);
232}
233