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>
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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>
63 #include "opt_inet6.h"
65 #include <sys/param.h>
66 #include <sys/systm.h>
67 #include <sys/eventhandler.h>
68 #include <sys/kernel.h>
70 #include <sys/malloc.h>
71 #include <sys/mutex.h>
73 #include <sys/errno.h>
74 #include <sys/socket.h>
77 #include <net/if_var.h>
79 #include <netinet/in.h>
80 #include <netinet/ip_var.h>
81 #include <netinet/ip_encap.h>
84 #include <netinet6/ip6_var.h>
87 static MALLOC_DEFINE(M_NETADDR, "encap_export_host",
88 "Export host address structure");
91 CK_LIST_ENTRY(encaptab) chain;
97 encap_lookup_t lookup;
103 CK_LIST_ENTRY(srcaddrtab) chain;
105 encap_srcaddr_t srcaddr;
109 CK_LIST_HEAD(encaptab_head, encaptab);
110 CK_LIST_HEAD(srcaddrtab_head, srcaddrtab);
112 static struct encaptab_head ipv4_encaptab = CK_LIST_HEAD_INITIALIZER();
113 static struct srcaddrtab_head ipv4_srcaddrtab = CK_LIST_HEAD_INITIALIZER();
116 static struct encaptab_head ipv6_encaptab = CK_LIST_HEAD_INITIALIZER();
117 static struct srcaddrtab_head ipv6_srcaddrtab = CK_LIST_HEAD_INITIALIZER();
120 static struct mtx encapmtx, srcaddrmtx;
121 MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
122 MTX_SYSINIT(srcaddrmtx, &srcaddrmtx, "srcaddrmtx", MTX_DEF);
123 #define ENCAP_WLOCK() mtx_lock(&encapmtx)
124 #define ENCAP_WUNLOCK() mtx_unlock(&encapmtx)
125 #define ENCAP_RLOCK_TRACKER struct epoch_tracker encap_et
126 #define ENCAP_RLOCK() NET_EPOCH_ENTER(encap_et)
127 #define ENCAP_RUNLOCK() NET_EPOCH_EXIT(encap_et)
128 #define ENCAP_WAIT() NET_EPOCH_WAIT()
130 #define SRCADDR_WLOCK() mtx_lock(&srcaddrmtx)
131 #define SRCADDR_WUNLOCK() mtx_unlock(&srcaddrmtx)
132 #define SRCADDR_RLOCK_TRACKER struct epoch_tracker srcaddr_et
133 #define SRCADDR_RLOCK() \
134 epoch_enter_preempt(net_epoch_preempt, &srcaddr_et)
135 #define SRCADDR_RUNLOCK() \
136 epoch_exit_preempt(net_epoch_preempt, &srcaddr_et)
137 #define SRCADDR_WAIT() epoch_wait_preempt(net_epoch_preempt)
140 * ifaddr_event_ext handler.
142 * Tunnelling interfaces may request the kernel to notify when
143 * some interface addresses appears or disappears. Usually tunnelling
144 * interface must use an address configured on the local machine as
145 * ingress address to be able receive datagramms and do not send
149 srcaddr_change_event(void *arg __unused, struct ifnet *ifp,
150 struct ifaddr *ifa, int event)
152 SRCADDR_RLOCK_TRACKER;
153 struct srcaddrtab_head *head;
154 struct srcaddrtab *p;
156 /* Support for old ifaddr_event. */
157 EVENTHANDLER_INVOKE(ifaddr_event, ifp);
159 switch (ifa->ifa_addr->sa_family) {
162 head = &ipv4_srcaddrtab;
167 head = &ipv6_srcaddrtab;
176 CK_LIST_FOREACH(p, head, chain) {
177 (*p->srcaddr)(p->arg, ifa->ifa_addr, event);
181 EVENTHANDLER_DEFINE(ifaddr_event_ext, srcaddr_change_event, NULL, 0);
183 static struct srcaddrtab *
184 encap_register_srcaddr(struct srcaddrtab_head *head, encap_srcaddr_t func,
185 void *arg, int mflags)
187 struct srcaddrtab *p, *tmp;
191 p = malloc(sizeof(*p), M_NETADDR, mflags);
198 CK_LIST_FOREACH(tmp, head, chain) {
199 if (func == tmp->srcaddr && arg == tmp->arg)
203 CK_LIST_INSERT_HEAD(head, p, chain);
214 encap_unregister_srcaddr(struct srcaddrtab_head *head,
215 const struct srcaddrtab *cookie)
217 struct srcaddrtab *p;
220 CK_LIST_FOREACH(p, head, chain) {
222 CK_LIST_REMOVE(p, chain);
233 static struct encaptab *
234 encap_attach(struct encaptab_head *head, const struct encap_config *cfg,
235 void *arg, int mflags)
237 struct encaptab *ep, *tmp;
239 if (cfg == NULL || cfg->input == NULL ||
240 (cfg->check == NULL && cfg->lookup == NULL) ||
241 (cfg->lookup != NULL && cfg->exact_match != ENCAP_DRV_LOOKUP) ||
242 (cfg->exact_match == ENCAP_DRV_LOOKUP && cfg->lookup == NULL))
245 ep = malloc(sizeof(*ep), M_NETADDR, mflags);
249 ep->proto = cfg->proto;
250 ep->min_length = cfg->min_length;
251 ep->exact_match = cfg->exact_match;
253 ep->lookup = cfg->exact_match == ENCAP_DRV_LOOKUP ? cfg->lookup: NULL;
254 ep->check = cfg->exact_match != ENCAP_DRV_LOOKUP ? cfg->check: NULL;
255 ep->input = cfg->input;
258 CK_LIST_FOREACH(tmp, head, chain) {
259 if (tmp->exact_match <= ep->exact_match)
263 CK_LIST_INSERT_HEAD(head, ep, chain);
265 CK_LIST_INSERT_BEFORE(tmp, ep, chain);
271 encap_detach(struct encaptab_head *head, const struct encaptab *cookie)
276 CK_LIST_FOREACH(ep, head, chain) {
278 CK_LIST_REMOVE(ep, chain);
290 encap_input(struct encaptab_head *head, struct mbuf *m, int off, int proto)
293 struct encaptab *ep, *match;
301 CK_LIST_FOREACH(ep, head, chain) {
302 if (ep->proto >= 0 && ep->proto != proto)
304 if (ep->min_length > m->m_pkthdr.len)
306 if (ep->exact_match == ENCAP_DRV_LOOKUP)
307 ret = (*ep->lookup)(m, off, proto, &arg);
309 ret = (*ep->check)(m, off, proto, ep->arg);
312 if (ret > matchprio) {
314 if (ep->exact_match != ENCAP_DRV_LOOKUP)
317 * No need to continue the search, we got the
320 if (ret >= ep->exact_match)
327 /* found a match, "match" has the best one */
328 ret = (*match->input)(m, off, proto, arg);
330 MPASS(ret == IPPROTO_DONE);
331 return (IPPROTO_DONE);
338 const struct srcaddrtab *
339 ip_encap_register_srcaddr(encap_srcaddr_t func, void *arg, int mflags)
342 return (encap_register_srcaddr(&ipv4_srcaddrtab, func, arg, mflags));
346 ip_encap_unregister_srcaddr(const struct srcaddrtab *cookie)
349 return (encap_unregister_srcaddr(&ipv4_srcaddrtab, cookie));
352 const struct encaptab *
353 ip_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
356 return (encap_attach(&ipv4_encaptab, cfg, arg, mflags));
360 ip_encap_detach(const struct encaptab *cookie)
363 return (encap_detach(&ipv4_encaptab, cookie));
367 encap4_input(struct mbuf **mp, int *offp, int proto)
370 if (encap_input(&ipv4_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
371 return (rip_input(mp, offp, proto));
372 return (IPPROTO_DONE);
377 const struct srcaddrtab *
378 ip6_encap_register_srcaddr(encap_srcaddr_t func, void *arg, int mflags)
381 return (encap_register_srcaddr(&ipv6_srcaddrtab, func, arg, mflags));
385 ip6_encap_unregister_srcaddr(const struct srcaddrtab *cookie)
388 return (encap_unregister_srcaddr(&ipv6_srcaddrtab, cookie));
391 const struct encaptab *
392 ip6_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
395 return (encap_attach(&ipv6_encaptab, cfg, arg, mflags));
399 ip6_encap_detach(const struct encaptab *cookie)
402 return (encap_detach(&ipv6_encaptab, cookie));
406 encap6_input(struct mbuf **mp, int *offp, int proto)
409 if (encap_input(&ipv6_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
410 return (rip6_input(mp, offp, proto));
411 return (IPPROTO_DONE);