414 lines
11 KiB
C
414 lines
11 KiB
C
/* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
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/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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* Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* My grandfather said that there's a devil inside tunnelling technology...
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*
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* We have surprisingly many protocols that want packets with IP protocol
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* #4 or #41. Here's a list of protocols that want protocol #41:
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* RFC1933 configured tunnel
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* RFC1933 automatic tunnel
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* RFC2401 IPsec tunnel
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* RFC2473 IPv6 generic packet tunnelling
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* RFC2529 6over4 tunnel
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* mobile-ip6 (uses RFC2473)
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* RFC3056 6to4 tunnel
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* isatap tunnel
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* Here's a list of protocol that want protocol #4:
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* RFC1853 IPv4-in-IPv4 tunnelling
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* RFC2003 IPv4 encapsulation within IPv4
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* RFC2344 reverse tunnelling for mobile-ip4
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* RFC2401 IPsec tunnel
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* Well, what can I say. They impose different en/decapsulation mechanism
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* from each other, so they need separate protocol handler. The only one
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* we can easily determine by protocol # is IPsec, which always has
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* AH/ESP/IPComp header right after outer IP header.
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*
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* So, clearly good old protosw does not work for protocol #4 and #41.
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* The code will let you match protocol via src/dst address pair.
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*/
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#include <sys/cdefs.h>
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/eventhandler.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/mbuf.h>
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#include <sys/errno.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <netinet/in.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip_encap.h>
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#ifdef INET6
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#include <netinet6/ip6_var.h>
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#endif
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static MALLOC_DEFINE(M_NETADDR, "encap_export_host",
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"Export host address structure");
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struct encaptab {
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CK_LIST_ENTRY(encaptab) chain;
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int proto;
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int min_length;
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int exact_match;
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void *arg;
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encap_lookup_t lookup;
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encap_check_t check;
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encap_input_t input;
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};
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struct srcaddrtab {
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CK_LIST_ENTRY(srcaddrtab) chain;
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encap_srcaddr_t srcaddr;
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void *arg;
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};
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CK_LIST_HEAD(encaptab_head, encaptab);
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CK_LIST_HEAD(srcaddrtab_head, srcaddrtab);
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#ifdef INET
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static struct encaptab_head ipv4_encaptab = CK_LIST_HEAD_INITIALIZER();
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static struct srcaddrtab_head ipv4_srcaddrtab = CK_LIST_HEAD_INITIALIZER();
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#endif
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#ifdef INET6
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static struct encaptab_head ipv6_encaptab = CK_LIST_HEAD_INITIALIZER();
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static struct srcaddrtab_head ipv6_srcaddrtab = CK_LIST_HEAD_INITIALIZER();
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#endif
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static struct mtx encapmtx, srcaddrmtx;
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MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
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MTX_SYSINIT(srcaddrmtx, &srcaddrmtx, "srcaddrmtx", MTX_DEF);
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#define ENCAP_WLOCK() mtx_lock(&encapmtx)
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#define ENCAP_WUNLOCK() mtx_unlock(&encapmtx)
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#define ENCAP_RLOCK_TRACKER struct epoch_tracker encap_et
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#define ENCAP_RLOCK() NET_EPOCH_ENTER(encap_et)
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#define ENCAP_RUNLOCK() NET_EPOCH_EXIT(encap_et)
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#define ENCAP_WAIT() NET_EPOCH_WAIT()
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#define SRCADDR_WLOCK() mtx_lock(&srcaddrmtx)
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#define SRCADDR_WUNLOCK() mtx_unlock(&srcaddrmtx)
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#define SRCADDR_RLOCK_TRACKER struct epoch_tracker srcaddr_et
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#define SRCADDR_RLOCK() \
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epoch_enter_preempt(net_epoch_preempt, &srcaddr_et)
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#define SRCADDR_RUNLOCK() \
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epoch_exit_preempt(net_epoch_preempt, &srcaddr_et)
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#define SRCADDR_WAIT() epoch_wait_preempt(net_epoch_preempt)
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/*
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* ifaddr_event_ext handler.
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*
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* Tunnelling interfaces may request the kernel to notify when
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* some interface addresses appears or disappears. Usually tunnelling
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* interface must use an address configured on the local machine as
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* ingress address to be able receive datagramms and do not send
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* spoofed packets.
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*/
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static void
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srcaddr_change_event(void *arg __unused, struct ifnet *ifp,
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struct ifaddr *ifa, int event)
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{
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SRCADDR_RLOCK_TRACKER;
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struct srcaddrtab_head *head;
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struct srcaddrtab *p;
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/* Support for old ifaddr_event. */
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EVENTHANDLER_INVOKE(ifaddr_event, ifp);
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switch (ifa->ifa_addr->sa_family) {
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#ifdef INET
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case AF_INET:
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head = &ipv4_srcaddrtab;
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break;
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#endif
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#ifdef INET6
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case AF_INET6:
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head = &ipv6_srcaddrtab;
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break;
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#endif
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default:
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/* ignore event */
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return;
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}
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SRCADDR_RLOCK();
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CK_LIST_FOREACH(p, head, chain) {
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(*p->srcaddr)(p->arg, ifa->ifa_addr, event);
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}
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SRCADDR_RUNLOCK();
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}
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EVENTHANDLER_DEFINE(ifaddr_event_ext, srcaddr_change_event, NULL, 0);
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static struct srcaddrtab *
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encap_register_srcaddr(struct srcaddrtab_head *head, encap_srcaddr_t func,
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void *arg, int mflags)
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{
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struct srcaddrtab *p, *tmp;
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if (func == NULL)
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return (NULL);
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p = malloc(sizeof(*p), M_NETADDR, mflags);
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if (p == NULL)
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return (NULL);
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p->srcaddr = func;
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p->arg = arg;
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SRCADDR_WLOCK();
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CK_LIST_FOREACH(tmp, head, chain) {
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if (func == tmp->srcaddr && arg == tmp->arg)
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break;
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}
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if (tmp == NULL)
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CK_LIST_INSERT_HEAD(head, p, chain);
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SRCADDR_WUNLOCK();
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if (tmp != NULL) {
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free(p, M_NETADDR);
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p = tmp;
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}
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return (p);
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}
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static int
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encap_unregister_srcaddr(struct srcaddrtab_head *head,
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const struct srcaddrtab *cookie)
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{
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struct srcaddrtab *p;
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SRCADDR_WLOCK();
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CK_LIST_FOREACH(p, head, chain) {
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if (p == cookie) {
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CK_LIST_REMOVE(p, chain);
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SRCADDR_WUNLOCK();
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SRCADDR_WAIT();
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free(p, M_NETADDR);
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return (0);
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}
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}
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SRCADDR_WUNLOCK();
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return (EINVAL);
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}
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static struct encaptab *
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encap_attach(struct encaptab_head *head, const struct encap_config *cfg,
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void *arg, int mflags)
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{
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struct encaptab *ep, *tmp;
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if (cfg == NULL || cfg->input == NULL ||
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(cfg->check == NULL && cfg->lookup == NULL) ||
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(cfg->lookup != NULL && cfg->exact_match != ENCAP_DRV_LOOKUP) ||
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(cfg->exact_match == ENCAP_DRV_LOOKUP && cfg->lookup == NULL))
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return (NULL);
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ep = malloc(sizeof(*ep), M_NETADDR, mflags);
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if (ep == NULL)
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return (NULL);
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ep->proto = cfg->proto;
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ep->min_length = cfg->min_length;
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ep->exact_match = cfg->exact_match;
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ep->arg = arg;
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ep->lookup = cfg->exact_match == ENCAP_DRV_LOOKUP ? cfg->lookup: NULL;
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ep->check = cfg->exact_match != ENCAP_DRV_LOOKUP ? cfg->check: NULL;
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ep->input = cfg->input;
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ENCAP_WLOCK();
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CK_LIST_FOREACH(tmp, head, chain) {
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if (tmp->exact_match <= ep->exact_match)
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break;
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}
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if (tmp == NULL)
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CK_LIST_INSERT_HEAD(head, ep, chain);
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else
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CK_LIST_INSERT_BEFORE(tmp, ep, chain);
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ENCAP_WUNLOCK();
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return (ep);
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}
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static int
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encap_detach(struct encaptab_head *head, const struct encaptab *cookie)
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{
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struct encaptab *ep;
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ENCAP_WLOCK();
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CK_LIST_FOREACH(ep, head, chain) {
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if (ep == cookie) {
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CK_LIST_REMOVE(ep, chain);
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ENCAP_WUNLOCK();
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ENCAP_WAIT();
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free(ep, M_NETADDR);
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return (0);
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}
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}
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ENCAP_WUNLOCK();
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return (EINVAL);
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}
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static int
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encap_input(struct encaptab_head *head, struct mbuf *m, int off, int proto)
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{
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ENCAP_RLOCK_TRACKER;
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struct encaptab *ep, *match;
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void *arg;
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int matchprio, ret;
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match = NULL;
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matchprio = 0;
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ENCAP_RLOCK();
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CK_LIST_FOREACH(ep, head, chain) {
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if (ep->proto >= 0 && ep->proto != proto)
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continue;
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if (ep->min_length > m->m_pkthdr.len)
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continue;
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if (ep->exact_match == ENCAP_DRV_LOOKUP)
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ret = (*ep->lookup)(m, off, proto, &arg);
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else
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ret = (*ep->check)(m, off, proto, ep->arg);
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if (ret <= 0)
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continue;
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if (ret > matchprio) {
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match = ep;
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if (ep->exact_match != ENCAP_DRV_LOOKUP)
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arg = ep->arg;
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/*
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* No need to continue the search, we got the
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* exact match.
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*/
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if (ret >= ep->exact_match)
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break;
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matchprio = ret;
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}
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}
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if (match != NULL) {
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/* found a match, "match" has the best one */
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ret = (*match->input)(m, off, proto, arg);
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ENCAP_RUNLOCK();
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MPASS(ret == IPPROTO_DONE);
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return (IPPROTO_DONE);
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}
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ENCAP_RUNLOCK();
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return (0);
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}
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#ifdef INET
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const struct srcaddrtab *
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ip_encap_register_srcaddr(encap_srcaddr_t func, void *arg, int mflags)
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{
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return (encap_register_srcaddr(&ipv4_srcaddrtab, func, arg, mflags));
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}
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int
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ip_encap_unregister_srcaddr(const struct srcaddrtab *cookie)
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{
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return (encap_unregister_srcaddr(&ipv4_srcaddrtab, cookie));
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}
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const struct encaptab *
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ip_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
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{
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return (encap_attach(&ipv4_encaptab, cfg, arg, mflags));
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}
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int
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ip_encap_detach(const struct encaptab *cookie)
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{
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return (encap_detach(&ipv4_encaptab, cookie));
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}
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int
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encap4_input(struct mbuf **mp, int *offp, int proto)
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{
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if (encap_input(&ipv4_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
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return (rip_input(mp, offp, proto));
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return (IPPROTO_DONE);
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}
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#endif /* INET */
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#ifdef INET6
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const struct srcaddrtab *
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ip6_encap_register_srcaddr(encap_srcaddr_t func, void *arg, int mflags)
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{
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return (encap_register_srcaddr(&ipv6_srcaddrtab, func, arg, mflags));
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}
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int
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ip6_encap_unregister_srcaddr(const struct srcaddrtab *cookie)
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{
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return (encap_unregister_srcaddr(&ipv6_srcaddrtab, cookie));
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}
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const struct encaptab *
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ip6_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
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{
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return (encap_attach(&ipv6_encaptab, cfg, arg, mflags));
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}
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int
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ip6_encap_detach(const struct encaptab *cookie)
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{
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return (encap_detach(&ipv6_encaptab, cookie));
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}
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int
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encap6_input(struct mbuf **mp, int *offp, int proto)
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{
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if (encap_input(&ipv6_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
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return (rip6_input(mp, offp, proto));
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return (IPPROTO_DONE);
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}
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#endif /* INET6 */
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