4736ccfd9c
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482 lines
12 KiB
C
482 lines
12 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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* 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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/* XXX is M_NETADDR correct? */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_mrouting.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/lock.h>
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#include <sys/mutex.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <sys/mbuf.h>
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#include <sys/errno.h>
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#include <sys/protosw.h>
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#include <sys/queue.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.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 <netinet/ip6.h>
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#include <netinet6/ip6_var.h>
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#endif
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#include <machine/stdarg.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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static MALLOC_DEFINE(M_NETADDR, "encap_export_host", "Export host address structure");
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static void encap_add(struct encaptab *);
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static int mask_match(const struct encaptab *, const struct sockaddr *,
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const struct sockaddr *);
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static void encap_fillarg(struct mbuf *, void *);
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/*
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* All global variables in ip_encap.c are locked using encapmtx.
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*/
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static struct mtx encapmtx;
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MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
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static LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(encaptab);
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/*
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* We currently keey encap_init() for source code compatibility reasons --
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* it's referenced by KAME pieces in netinet6.
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*/
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void
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encap_init(void)
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{
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}
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#ifdef INET
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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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struct ip *ip;
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struct mbuf *m;
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struct sockaddr_in s, d;
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const struct protosw *psw;
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struct encaptab *ep, *match;
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void *arg;
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int matchprio, off, prio;
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m = *mp;
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off = *offp;
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ip = mtod(m, struct ip *);
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bzero(&s, sizeof(s));
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s.sin_family = AF_INET;
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s.sin_len = sizeof(struct sockaddr_in);
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s.sin_addr = ip->ip_src;
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bzero(&d, sizeof(d));
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d.sin_family = AF_INET;
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d.sin_len = sizeof(struct sockaddr_in);
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d.sin_addr = ip->ip_dst;
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arg = NULL;
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psw = NULL;
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match = NULL;
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matchprio = 0;
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mtx_lock(&encapmtx);
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LIST_FOREACH(ep, &encaptab, chain) {
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if (ep->af != AF_INET)
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continue;
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if (ep->proto >= 0 && ep->proto != proto)
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continue;
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if (ep->func)
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prio = (*ep->func)(m, off, proto, ep->arg);
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else {
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/*
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* it's inbound traffic, we need to match in reverse
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* order
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*/
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prio = mask_match(ep, (struct sockaddr *)&d,
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(struct sockaddr *)&s);
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}
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/*
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* We prioritize the matches by using bit length of the
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* matches. mask_match() and user-supplied matching function
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* should return the bit length of the matches (for example,
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* if both src/dst are matched for IPv4, 64 should be returned).
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* 0 or negative return value means "it did not match".
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*
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* The question is, since we have two "mask" portion, we
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* cannot really define total order between entries.
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* For example, which of these should be preferred?
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* mask_match() returns 48 (32 + 16) for both of them.
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* src=3ffe::/16, dst=3ffe:501::/32
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* src=3ffe:501::/32, dst=3ffe::/16
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*
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* We need to loop through all the possible candidates
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* to get the best match - the search takes O(n) for
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* n attachments (i.e. interfaces).
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*/
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if (prio <= 0)
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continue;
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if (prio > matchprio) {
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matchprio = prio;
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match = ep;
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}
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}
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if (match != NULL) {
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psw = match->psw;
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arg = match->arg;
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}
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mtx_unlock(&encapmtx);
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if (match != NULL) {
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/* found a match, "match" has the best one */
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if (psw != NULL && psw->pr_input != NULL) {
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encap_fillarg(m, arg);
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(*psw->pr_input)(mp, offp, proto);
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} else
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m_freem(m);
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return (IPPROTO_DONE);
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}
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/* last resort: inject to raw socket */
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return (rip_input(mp, offp, proto));
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}
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#endif
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#ifdef INET6
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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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struct mbuf *m = *mp;
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struct ip6_hdr *ip6;
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struct sockaddr_in6 s, d;
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const struct protosw *psw;
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struct encaptab *ep, *match;
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void *arg;
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int prio, matchprio;
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ip6 = mtod(m, struct ip6_hdr *);
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bzero(&s, sizeof(s));
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s.sin6_family = AF_INET6;
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s.sin6_len = sizeof(struct sockaddr_in6);
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s.sin6_addr = ip6->ip6_src;
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bzero(&d, sizeof(d));
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d.sin6_family = AF_INET6;
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d.sin6_len = sizeof(struct sockaddr_in6);
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d.sin6_addr = ip6->ip6_dst;
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arg = NULL;
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psw = NULL;
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match = NULL;
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matchprio = 0;
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mtx_lock(&encapmtx);
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LIST_FOREACH(ep, &encaptab, chain) {
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if (ep->af != AF_INET6)
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continue;
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if (ep->proto >= 0 && ep->proto != proto)
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continue;
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if (ep->func)
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prio = (*ep->func)(m, *offp, proto, ep->arg);
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else {
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/*
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* it's inbound traffic, we need to match in reverse
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* order
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*/
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prio = mask_match(ep, (struct sockaddr *)&d,
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(struct sockaddr *)&s);
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}
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/* see encap4_input() for issues here */
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if (prio <= 0)
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continue;
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if (prio > matchprio) {
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matchprio = prio;
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match = ep;
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}
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}
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if (match != NULL) {
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psw = match->psw;
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arg = match->arg;
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}
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mtx_unlock(&encapmtx);
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if (match != NULL) {
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/* found a match */
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if (psw != NULL && psw->pr_input != NULL) {
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encap_fillarg(m, arg);
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return (*psw->pr_input)(mp, offp, proto);
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} else {
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m_freem(m);
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return (IPPROTO_DONE);
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}
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}
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/* last resort: inject to raw socket */
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return rip6_input(mp, offp, proto);
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}
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#endif
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/*lint -sem(encap_add, custodial(1)) */
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static void
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encap_add(struct encaptab *ep)
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{
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mtx_assert(&encapmtx, MA_OWNED);
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LIST_INSERT_HEAD(&encaptab, ep, chain);
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}
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/*
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* sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
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* length of mask (sm and dm) is assumed to be same as sp/dp.
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* Return value will be necessary as input (cookie) for encap_detach().
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*/
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const struct encaptab *
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encap_attach(int af, int proto, const struct sockaddr *sp,
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const struct sockaddr *sm, const struct sockaddr *dp,
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const struct sockaddr *dm, const struct protosw *psw, void *arg)
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{
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struct encaptab *ep;
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/* sanity check on args */
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if (sp->sa_len > sizeof(ep->src) || dp->sa_len > sizeof(ep->dst))
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return (NULL);
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if (sp->sa_len != dp->sa_len)
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return (NULL);
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if (af != sp->sa_family || af != dp->sa_family)
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return (NULL);
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/* check if anyone have already attached with exactly same config */
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mtx_lock(&encapmtx);
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LIST_FOREACH(ep, &encaptab, chain) {
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if (ep->af != af)
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continue;
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if (ep->proto != proto)
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continue;
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if (ep->src.ss_len != sp->sa_len ||
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bcmp(&ep->src, sp, sp->sa_len) != 0 ||
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bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
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continue;
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if (ep->dst.ss_len != dp->sa_len ||
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bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
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bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
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continue;
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mtx_unlock(&encapmtx);
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return (NULL);
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}
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ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
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if (ep == NULL) {
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mtx_unlock(&encapmtx);
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return (NULL);
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}
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bzero(ep, sizeof(*ep));
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ep->af = af;
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ep->proto = proto;
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bcopy(sp, &ep->src, sp->sa_len);
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bcopy(sm, &ep->srcmask, sp->sa_len);
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bcopy(dp, &ep->dst, dp->sa_len);
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bcopy(dm, &ep->dstmask, dp->sa_len);
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ep->psw = psw;
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ep->arg = arg;
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encap_add(ep);
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mtx_unlock(&encapmtx);
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return (ep);
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}
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const struct encaptab *
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encap_attach_func(int af, int proto,
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int (*func)(const struct mbuf *, int, int, void *),
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const struct protosw *psw, void *arg)
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{
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struct encaptab *ep;
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/* sanity check on args */
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if (!func)
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return (NULL);
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ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
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if (ep == NULL)
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return (NULL);
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bzero(ep, sizeof(*ep));
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ep->af = af;
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ep->proto = proto;
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ep->func = func;
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ep->psw = psw;
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ep->arg = arg;
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mtx_lock(&encapmtx);
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encap_add(ep);
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mtx_unlock(&encapmtx);
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return (ep);
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}
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int
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encap_detach(const struct encaptab *cookie)
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{
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const struct encaptab *ep = cookie;
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struct encaptab *p;
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mtx_lock(&encapmtx);
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LIST_FOREACH(p, &encaptab, chain) {
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if (p == ep) {
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LIST_REMOVE(p, chain);
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mtx_unlock(&encapmtx);
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free(p, M_NETADDR); /*XXX*/
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return 0;
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}
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}
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mtx_unlock(&encapmtx);
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return EINVAL;
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}
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static int
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mask_match(const struct encaptab *ep, const struct sockaddr *sp,
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const struct sockaddr *dp)
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{
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struct sockaddr_storage s;
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struct sockaddr_storage d;
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int i;
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const u_int8_t *p, *q;
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u_int8_t *r;
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int matchlen;
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if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
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return 0;
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if (sp->sa_family != ep->af || dp->sa_family != ep->af)
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return 0;
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if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
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return 0;
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matchlen = 0;
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p = (const u_int8_t *)sp;
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q = (const u_int8_t *)&ep->srcmask;
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r = (u_int8_t *)&s;
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for (i = 0 ; i < sp->sa_len; i++) {
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r[i] = p[i] & q[i];
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/* XXX estimate */
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matchlen += (q[i] ? 8 : 0);
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}
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p = (const u_int8_t *)dp;
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q = (const u_int8_t *)&ep->dstmask;
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r = (u_int8_t *)&d;
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for (i = 0 ; i < dp->sa_len; i++) {
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r[i] = p[i] & q[i];
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/* XXX rough estimate */
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matchlen += (q[i] ? 8 : 0);
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}
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/* need to overwrite len/family portion as we don't compare them */
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s.ss_len = sp->sa_len;
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s.ss_family = sp->sa_family;
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d.ss_len = dp->sa_len;
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d.ss_family = dp->sa_family;
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if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
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bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
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return matchlen;
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} else
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return 0;
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}
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static void
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encap_fillarg(struct mbuf *m, void *arg)
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{
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struct m_tag *tag;
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if (arg != NULL) {
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tag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), M_NOWAIT);
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if (tag != NULL) {
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*(void**)(tag+1) = arg;
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m_tag_prepend(m, tag);
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}
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}
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}
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void *
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encap_getarg(struct mbuf *m)
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{
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void *p = NULL;
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struct m_tag *tag;
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tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
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if (tag) {
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p = *(void**)(tag+1);
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m_tag_delete(m, tag);
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}
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return p;
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}
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