1 /* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
4 * SPDX-License-Identifier: BSD-3-Clause
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org>
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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14 * notice, this list of conditions and the following disclaimer.
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20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * My grandfather said that there's a devil inside tunnelling technology...
37 * We have surprisingly many protocols that want packets with IP protocol
38 * #4 or #41. Here's a list of protocols that want protocol #41:
39 * RFC1933 configured tunnel
40 * RFC1933 automatic tunnel
41 * RFC2401 IPsec tunnel
42 * RFC2473 IPv6 generic packet tunnelling
43 * RFC2529 6over4 tunnel
44 * mobile-ip6 (uses RFC2473)
47 * Here's a list of protocol that want protocol #4:
48 * RFC1853 IPv4-in-IPv4 tunnelling
49 * RFC2003 IPv4 encapsulation within IPv4
50 * RFC2344 reverse tunnelling for mobile-ip4
51 * RFC2401 IPsec tunnel
52 * Well, what can I say. They impose different en/decapsulation mechanism
53 * from each other, so they need separate protocol handler. The only one
54 * we can easily determine by protocol # is IPsec, which always has
55 * AH/ESP/IPComp header right after outer IP header.
57 * So, clearly good old protosw does not work for protocol #4 and #41.
58 * The code will let you match protocol via src/dst address pair.
61 #include <sys/cdefs.h>
62 __FBSDID("$FreeBSD$");
65 #include "opt_inet6.h"
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/eventhandler.h>
70 #include <sys/kernel.h>
72 #include <sys/malloc.h>
73 #include <sys/mutex.h>
75 #include <sys/errno.h>
76 #include <sys/socket.h>
79 #include <net/if_var.h>
81 #include <netinet/in.h>
82 #include <netinet/ip_var.h>
83 #include <netinet/ip_encap.h>
86 #include <netinet6/ip6_var.h>
89 static MALLOC_DEFINE(M_NETADDR, "encap_export_host",
90 "Export host address structure");
93 CK_LIST_ENTRY(encaptab) chain;
99 encap_lookup_t lookup;
105 CK_LIST_ENTRY(srcaddrtab) chain;
107 encap_srcaddr_t srcaddr;
111 CK_LIST_HEAD(encaptab_head, encaptab);
112 CK_LIST_HEAD(srcaddrtab_head, srcaddrtab);
114 static struct encaptab_head ipv4_encaptab = CK_LIST_HEAD_INITIALIZER();
115 static struct srcaddrtab_head ipv4_srcaddrtab = CK_LIST_HEAD_INITIALIZER();
118 static struct encaptab_head ipv6_encaptab = CK_LIST_HEAD_INITIALIZER();
119 static struct srcaddrtab_head ipv6_srcaddrtab = CK_LIST_HEAD_INITIALIZER();
122 static struct mtx encapmtx, srcaddrmtx;
123 MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
124 MTX_SYSINIT(srcaddrmtx, &srcaddrmtx, "srcaddrmtx", MTX_DEF);
125 #define ENCAP_WLOCK() mtx_lock(&encapmtx)
126 #define ENCAP_WUNLOCK() mtx_unlock(&encapmtx)
127 #define ENCAP_RLOCK_TRACKER struct epoch_tracker encap_et
128 #define ENCAP_RLOCK() \
129 epoch_enter_preempt(net_epoch_preempt, &encap_et)
130 #define ENCAP_RUNLOCK() \
131 epoch_exit_preempt(net_epoch_preempt, &encap_et)
132 #define ENCAP_WAIT() epoch_wait_preempt(net_epoch_preempt)
134 #define SRCADDR_WLOCK() mtx_lock(&srcaddrmtx)
135 #define SRCADDR_WUNLOCK() mtx_unlock(&srcaddrmtx)
136 #define SRCADDR_RLOCK_TRACKER struct epoch_tracker srcaddr_et
137 #define SRCADDR_RLOCK() \
138 epoch_enter_preempt(net_epoch_preempt, &srcaddr_et)
139 #define SRCADDR_RUNLOCK() \
140 epoch_exit_preempt(net_epoch_preempt, &srcaddr_et)
141 #define SRCADDR_WAIT() epoch_wait_preempt(net_epoch_preempt)
144 * ifaddr_event_ext handler.
146 * Tunnelling interfaces may request the kernel to notify when
147 * some interface addresses appears or disappears. Usually tunnelling
148 * interface must use an address configured on the local machine as
149 * ingress address to be able receive datagramms and do not send
153 srcaddr_change_event(void *arg __unused, struct ifnet *ifp,
154 struct ifaddr *ifa, int event)
156 SRCADDR_RLOCK_TRACKER;
157 struct srcaddrtab_head *head;
158 struct srcaddrtab *p;
160 /* Support for old ifaddr_event. */
161 EVENTHANDLER_INVOKE(ifaddr_event, ifp);
163 switch (ifa->ifa_addr->sa_family) {
166 head = &ipv4_srcaddrtab;
171 head = &ipv6_srcaddrtab;
180 CK_LIST_FOREACH(p, head, chain) {
181 (*p->srcaddr)(p->arg, ifa->ifa_addr, event);
185 EVENTHANDLER_DEFINE(ifaddr_event_ext, srcaddr_change_event, NULL, 0);
187 static struct srcaddrtab *
188 encap_register_srcaddr(struct srcaddrtab_head *head, encap_srcaddr_t func,
189 void *arg, int mflags)
191 struct srcaddrtab *p, *tmp;
195 p = malloc(sizeof(*p), M_NETADDR, mflags);
202 CK_LIST_FOREACH(tmp, head, chain) {
203 if (func == tmp->srcaddr && arg == tmp->arg)
207 CK_LIST_INSERT_HEAD(head, p, chain);
218 encap_unregister_srcaddr(struct srcaddrtab_head *head,
219 const struct srcaddrtab *cookie)
221 struct srcaddrtab *p;
224 CK_LIST_FOREACH(p, head, chain) {
226 CK_LIST_REMOVE(p, chain);
237 static struct encaptab *
238 encap_attach(struct encaptab_head *head, const struct encap_config *cfg,
239 void *arg, int mflags)
241 struct encaptab *ep, *tmp;
243 if (cfg == NULL || cfg->input == NULL ||
244 (cfg->check == NULL && cfg->lookup == NULL) ||
245 (cfg->lookup != NULL && cfg->exact_match != ENCAP_DRV_LOOKUP) ||
246 (cfg->exact_match == ENCAP_DRV_LOOKUP && cfg->lookup == NULL))
249 ep = malloc(sizeof(*ep), M_NETADDR, mflags);
253 ep->proto = cfg->proto;
254 ep->min_length = cfg->min_length;
255 ep->exact_match = cfg->exact_match;
257 ep->lookup = cfg->exact_match == ENCAP_DRV_LOOKUP ? cfg->lookup: NULL;
258 ep->check = cfg->exact_match != ENCAP_DRV_LOOKUP ? cfg->check: NULL;
259 ep->input = cfg->input;
262 CK_LIST_FOREACH(tmp, head, chain) {
263 if (tmp->exact_match <= ep->exact_match)
267 CK_LIST_INSERT_HEAD(head, ep, chain);
269 CK_LIST_INSERT_BEFORE(tmp, ep, chain);
275 encap_detach(struct encaptab_head *head, const struct encaptab *cookie)
280 CK_LIST_FOREACH(ep, head, chain) {
282 CK_LIST_REMOVE(ep, chain);
294 encap_input(struct encaptab_head *head, struct mbuf *m, int off, int proto)
297 struct encaptab *ep, *match;
305 CK_LIST_FOREACH(ep, head, chain) {
306 if (ep->proto >= 0 && ep->proto != proto)
308 if (ep->min_length > m->m_pkthdr.len)
310 if (ep->exact_match == ENCAP_DRV_LOOKUP)
311 ret = (*ep->lookup)(m, off, proto, &arg);
313 ret = (*ep->check)(m, off, proto, ep->arg);
316 if (ret > matchprio) {
318 if (ep->exact_match != ENCAP_DRV_LOOKUP)
321 * No need to continue the search, we got the
324 if (ret >= ep->exact_match)
331 /* found a match, "match" has the best one */
332 ret = (*match->input)(m, off, proto, arg);
334 MPASS(ret == IPPROTO_DONE);
335 return (IPPROTO_DONE);
342 const struct srcaddrtab *
343 ip_encap_register_srcaddr(encap_srcaddr_t func, void *arg, int mflags)
346 return (encap_register_srcaddr(&ipv4_srcaddrtab, func, arg, mflags));
350 ip_encap_unregister_srcaddr(const struct srcaddrtab *cookie)
353 return (encap_unregister_srcaddr(&ipv4_srcaddrtab, cookie));
356 const struct encaptab *
357 ip_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
360 return (encap_attach(&ipv4_encaptab, cfg, arg, mflags));
364 ip_encap_detach(const struct encaptab *cookie)
367 return (encap_detach(&ipv4_encaptab, cookie));
371 encap4_input(struct mbuf **mp, int *offp, int proto)
374 if (encap_input(&ipv4_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
375 return (rip_input(mp, offp, proto));
376 return (IPPROTO_DONE);
381 const struct srcaddrtab *
382 ip6_encap_register_srcaddr(encap_srcaddr_t func, void *arg, int mflags)
385 return (encap_register_srcaddr(&ipv6_srcaddrtab, func, arg, mflags));
389 ip6_encap_unregister_srcaddr(const struct srcaddrtab *cookie)
392 return (encap_unregister_srcaddr(&ipv6_srcaddrtab, cookie));
395 const struct encaptab *
396 ip6_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
399 return (encap_attach(&ipv6_encaptab, cfg, arg, mflags));
403 ip6_encap_detach(const struct encaptab *cookie)
406 return (encap_detach(&ipv6_encaptab, cookie));
410 encap6_input(struct mbuf **mp, int *offp, int proto)
413 if (encap_input(&ipv6_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
414 return (rip6_input(mp, offp, proto));
415 return (IPPROTO_DONE);