527 lines
13 KiB
C
527 lines
13 KiB
C
/* $NetBSD: ah_output.c,v 1.4 1999/07/30 10:35:35 itojun Exp $ */
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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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* RFC1826/2402 authentication header.
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*/
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#if (defined(__FreeBSD__) && __FreeBSD__ >= 3) || defined(__NetBSD__)
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#include "opt_inet.h"
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#endif
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#define ahdprintf(x) printf x
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/domain.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/errno.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/syslog.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/in_var.h>
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#include <netinet/in_pcb.h>
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#ifdef INET6
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#include <netinet6/ip6.h>
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#if !defined(__FreeBSD__) || __FreeBSD__ < 3
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#include <netinet6/in6_pcb.h>
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#endif
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#include <netinet6/ip6_var.h>
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#include <netinet6/icmp6.h>
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#endif
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#include <netinet6/ipsec.h>
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#include <netinet6/ah.h>
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#include <netkey/key.h>
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#include <netkey/keydb.h>
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#include <netkey/key_debug.h>
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static struct in_addr *ah4_finaldst __P((struct mbuf *));
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/*
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* compute AH header size.
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* transport mode only. for tunnel mode, we should implement
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* virtual interface, and control MTU/MSS by the interface MTU.
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*/
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size_t
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ah_hdrsiz(isr)
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struct ipsecrequest *isr;
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{
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struct ah_algorithm *algo;
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size_t hdrsiz;
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/* sanity check */
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if (isr == NULL)
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panic("ah_hdrsiz: NULL was passed.\n");
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if (isr->proto != IPPROTO_AH)
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panic("unsupported mode passed to ah_hdrsiz");
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if (isr->sa == NULL)
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goto contrive;
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if (isr->sa->state != SADB_SASTATE_MATURE
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&& isr->sa->state != SADB_SASTATE_DYING)
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goto contrive;
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/* we need transport mode AH. */
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algo = &ah_algorithms[isr->sa->alg_auth];
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if (!algo)
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goto contrive;
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/*
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* XXX
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* right now we don't calcurate the padding size. simply
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* treat the padding size as constant, for simplicity.
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*
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* XXX variable size padding support
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*/
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hdrsiz = (((*algo->sumsiz)(isr->sa) + 3) & ~(4 - 1));
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if (isr->sa->flags & SADB_X_EXT_OLD)
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hdrsiz += sizeof(struct ah);
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else
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hdrsiz += sizeof(struct newah);
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return hdrsiz;
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contrive:
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/* ASSUMING:
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* sizeof(struct newah) > sizeof(struct ah).
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* 16 = (16 + 3) & ~(4 - 1).
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*/
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return sizeof(struct newah) + 16;
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}
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/*
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* Modify the packet so that it includes the authentication data.
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* The mbuf passed must start with IPv4 header.
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*
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* assumes that the first mbuf contains IPv4 header + option only.
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* the function does not modify m.
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*/
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int
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ah4_output(m, isr)
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struct mbuf *m;
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struct ipsecrequest *isr;
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{
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struct secas *sa = isr->sa;
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struct ah_algorithm *algo;
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u_int32_t spi;
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u_char *ahdrpos;
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u_char *ahsumpos = NULL;
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size_t hlen = 0; /*IP header+option in bytes*/
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size_t plen = 0; /*AH payload size in bytes*/
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size_t ahlen = 0; /*plen + sizeof(ah)*/
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struct ip *ip;
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struct in_addr dst;
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struct in_addr *finaldst;
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int error;
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/* sanity checks */
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if ((sa->flags & SADB_X_EXT_OLD) == 0 && !sa->replay) {
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struct ip *ip;
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ip = mtod(m, struct ip *);
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printf("ah4_output: internal error: "
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"sa->replay is null: "
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"%x->%x, SPI=%u\n",
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(u_int32_t)ntohl(ip->ip_src.s_addr),
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(u_int32_t)ntohl(ip->ip_dst.s_addr),
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(u_int32_t)ntohl(sa->spi));
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ipsecstat.out_inval++;
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m_freem(m);
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return EINVAL;
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}
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algo = &ah_algorithms[sa->alg_auth];
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spi = sa->spi;
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/*
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* determine the size to grow.
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*/
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if (sa->flags & SADB_X_EXT_OLD) {
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/* RFC 1826 */
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plen = ((*algo->sumsiz)(sa) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
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ahlen = plen + sizeof(struct ah);
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} else {
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/* RFC 2402 */
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plen = ((*algo->sumsiz)(sa) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
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ahlen = plen + sizeof(struct newah);
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}
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/*
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* grow the mbuf to accomodate AH.
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*/
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ip = mtod(m, struct ip *);
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#ifdef _IP_VHL
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hlen = IP_VHL_HL(ip->ip_vhl) << 2;
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#else
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hlen = ip->ip_hl << 2;
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#endif
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if (m->m_len != hlen)
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panic("ah4_output: assumption failed (first mbuf length)");
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if (M_LEADINGSPACE(m->m_next) < ahlen) {
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struct mbuf *n;
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MGET(n, M_DONTWAIT, MT_DATA);
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if (!n) {
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printf("ENOBUFS in ah4_output %d\n", __LINE__);
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m_freem(m);
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return ENOBUFS;
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}
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n->m_len = ahlen;
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n->m_next = m->m_next;
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m->m_next = n;
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m->m_pkthdr.len += ahlen;
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ahdrpos = mtod(n, u_char *);
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} else {
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m->m_next->m_len += ahlen;
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m->m_next->m_data -= ahlen;
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m->m_pkthdr.len += ahlen;
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ahdrpos = mtod(m->m_next, u_char *);
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}
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ip = mtod(m, struct ip *); /*just to be sure*/
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/*
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* initialize AH.
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*/
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if (sa->flags & SADB_X_EXT_OLD) {
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struct ah *ahdr;
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ahdr = (struct ah *)ahdrpos;
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ahsumpos = (u_char *)(ahdr + 1);
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ahdr->ah_len = plen >> 2;
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ahdr->ah_nxt = ip->ip_p;
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ahdr->ah_reserve = htons(0);
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ahdr->ah_spi = spi;
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bzero(ahdr + 1, plen);
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} else {
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struct newah *ahdr;
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ahdr = (struct newah *)ahdrpos;
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ahsumpos = (u_char *)(ahdr + 1);
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ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
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ahdr->ah_nxt = ip->ip_p;
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ahdr->ah_reserve = htons(0);
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ahdr->ah_spi = spi;
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sa->replay->count++;
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/*
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* XXX sequence number must not be cycled, if the SA is
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* installed by IKE daemon.
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*/
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ahdr->ah_seq = htonl(sa->replay->count);
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bzero(ahdr + 1, plen);
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}
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/*
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* modify IPv4 header.
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*/
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ip->ip_p = IPPROTO_AH;
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if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
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ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
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else {
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printf("IPv4 AH output: size exceeds limit\n");
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ipsecstat.out_inval++;
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m_freem(m);
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return EMSGSIZE;
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}
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/*
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* If there is source routing option, update destination field in
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* the IPv4 header to the final destination.
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* Note that we do not need to update source routing option itself
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* (as done in IPv4 AH processing -- see ip6_output()), since
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* source routing option is not part of the ICV computation.
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*/
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finaldst = ah4_finaldst(m);
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if (finaldst) {
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dst.s_addr = ip->ip_dst.s_addr;
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ip->ip_dst.s_addr = finaldst->s_addr;
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}
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/*
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* calcurate the checksum, based on security association
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* and the algorithm specified.
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*/
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error = ah4_calccksum(m, (caddr_t)ahsumpos, algo, sa);
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if (error) {
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printf("error after ah4_calccksum, called from ah4_output");
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m = NULL;
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ipsecstat.out_inval++;
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return error;
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}
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if (finaldst) {
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ip = mtod(m, struct ip *); /*just to make sure*/
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ip->ip_dst.s_addr = dst.s_addr;
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}
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ipsecstat.out_success++;
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ipsecstat.out_ahhist[sa->alg_auth]++;
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key_sa_recordxfer(sa, m);
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return 0;
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}
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/* Calculate AH length */
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int
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ah_hdrlen(sa)
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struct secas *sa;
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{
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struct ah_algorithm *algo;
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int plen, ahlen;
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algo = &ah_algorithms[sa->alg_auth];
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if (sa->flags & SADB_X_EXT_OLD) {
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/* RFC 1826 */
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plen = ((*algo->sumsiz)(sa) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
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ahlen = plen + sizeof(struct ah);
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} else {
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/* RFC 2402 */
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plen = ((*algo->sumsiz)(sa) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
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ahlen = plen + sizeof(struct newah);
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}
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return(ahlen);
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}
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#ifdef INET6
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/*
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* Fill in the Authentication Header and calculate checksum.
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*/
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int
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ah6_output(m, nexthdrp, md, isr)
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struct mbuf *m;
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u_char *nexthdrp;
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struct mbuf *md;
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struct ipsecrequest *isr;
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{
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struct mbuf *mprev;
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struct mbuf *mah;
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struct secas *sa = isr->sa;
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struct ah_algorithm *algo;
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u_int32_t spi;
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u_char *ahsumpos = NULL;
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size_t plen; /*AH payload size in bytes*/
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int error = 0;
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int ahlen;
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struct ip6_hdr *ip6;
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if (m->m_len < sizeof(struct ip6_hdr)) {
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printf("ah6_output: first mbuf too short\n");
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m_freem(m);
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return EINVAL;
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}
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ahlen = ah_hdrlen(sa);
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if (ahlen == 0)
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return 0;
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for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
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;
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if (!mprev || mprev->m_next != md) {
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printf("ah6_output: md is not in chain\n");
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m_freem(m);
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return EINVAL;
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}
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MGET(mah, M_DONTWAIT, MT_DATA);
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if (!mah) {
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m_freem(m);
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return ENOBUFS;
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}
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if (ahlen > MLEN) {
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MCLGET(mah, M_DONTWAIT);
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if ((mah->m_flags & M_EXT) == 0) {
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m_free(mah);
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m_freem(m);
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return ENOBUFS;
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}
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}
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mah->m_len = ahlen;
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mah->m_next = md;
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mprev->m_next = mah;
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m->m_pkthdr.len += ahlen;
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/* fix plen */
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if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
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printf("ip6_output: AH with IPv6 jumbogram is not supported\n");
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m_freem(m);
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return EINVAL;
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}
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ip6 = mtod(m, struct ip6_hdr *);
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ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
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if ((sa->flags & SADB_X_EXT_OLD) == 0 && !sa->replay) {
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printf("ah6_output: internal error: "
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"sa->replay is null: SPI=%u\n",
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(u_int32_t)ntohl(sa->spi));
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ipsec6stat.out_inval++;
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return 0; /* no change at all */
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}
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algo = &ah_algorithms[sa->alg_auth];
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spi = sa->spi;
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/*
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* initialize AH.
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*/
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if (sa->flags & SADB_X_EXT_OLD) {
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struct ah *ahdr = mtod(mah, struct ah *);
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plen = mah->m_len - sizeof(struct ah);
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ahsumpos = (u_char *)(ahdr + 1);
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ahdr->ah_nxt = *nexthdrp;
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*nexthdrp = IPPROTO_AH;
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ahdr->ah_len = plen >> 2;
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ahdr->ah_reserve = htons(0);
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ahdr->ah_spi = spi;
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bzero(ahdr + 1, plen);
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} else {
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struct newah *ahdr = mtod(mah, struct newah *);
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plen = mah->m_len - sizeof(struct newah);
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ahsumpos = (u_char *)(ahdr + 1);
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ahdr->ah_nxt = *nexthdrp;
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*nexthdrp = IPPROTO_AH;
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ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
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ahdr->ah_reserve = htons(0);
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ahdr->ah_spi = spi;
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sa->replay->count++;
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/*
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* XXX sequence number must not be cycled, if the SA is
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* installed by IKE daemon.
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*/
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ahdr->ah_seq = htonl(sa->replay->count);
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bzero(ahdr + 1, plen);
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}
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/*
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* calcurate the checksum, based on security association
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* and the algorithm specified.
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*/
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error = ah6_calccksum(m, (caddr_t)ahsumpos, algo, sa);
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if (error)
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ipsec6stat.out_inval++;
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else
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ipsec6stat.out_success++;
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ipsec6stat.out_ahhist[sa->alg_auth]++;
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key_sa_recordxfer(sa, m);
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return(error);
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}
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#endif
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/*
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* Find the final destination if there is loose/strict source routing option.
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* Returns NULL if there's no source routing options.
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* Returns NULL on errors too.
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* Note that this function will return a pointer INTO the given parameter,
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* struct mbuf *m.
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* The mbuf must be pulled up toward, at least, ip option part.
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*/
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static struct in_addr *
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ah4_finaldst(m)
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struct mbuf *m;
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{
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struct ip *ip;
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int optlen;
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u_char *q;
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int i;
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int hlen;
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if (!m)
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panic("ah4_finaldst: m == NULL");
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ip = mtod(m, struct ip *);
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hlen = (ip->ip_hl << 2);
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if (m->m_len < hlen) {
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printf("ah4_finaldst: parameter mbuf wrong (not pulled up)\n");
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return NULL;
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}
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if (hlen == sizeof(struct ip))
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return NULL;
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optlen = hlen - sizeof(struct ip);
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if (optlen < 0) {
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printf("ah4_finaldst: wrong optlen %d\n", optlen);
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return NULL;
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}
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q = (u_char *)(ip + 1);
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i = 0;
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while (i < optlen) {
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switch (q[i + IPOPT_OPTVAL]) {
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case IPOPT_EOL:
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i = optlen; /* bye */
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break;
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case IPOPT_NOP:
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i++;
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break;
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case IPOPT_LSRR:
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case IPOPT_SSRR:
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if (q[i + IPOPT_OLEN] <= 0
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|| optlen - i < q[i + IPOPT_OLEN]) {
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printf("ip_finaldst: invalid IP option "
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"(code=%02x len=%02x)\n",
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q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]);
|
|
return NULL;
|
|
}
|
|
i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
|
|
return (struct in_addr *)(q + i);
|
|
default:
|
|
if (q[i + IPOPT_OLEN] <= 0
|
|
|| optlen - i < q[i + IPOPT_OLEN]) {
|
|
printf("ip_finaldst: invalid IP option "
|
|
"(code=%02x len=%02x)\n",
|
|
q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]);
|
|
return NULL;
|
|
}
|
|
i += q[i + IPOPT_OLEN];
|
|
break;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|