344 lines
8.1 KiB
C
344 lines
8.1 KiB
C
/* $NetBSD$ */
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/*
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* Copyright (C) 2001-2003 by Darren Reed
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*
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* See the IPFILTER.LICENCE file for details on licencing.
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*
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* Simple ISAKMP transparent proxy for in-kernel use. For use with the NAT
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* code.
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*
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* Id: ip_ipsec_pxy.c,v 2.20.2.6 2005/03/28 10:47:53 darrenr Exp
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*
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*/
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#define IPF_IPSEC_PROXY
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int ippr_ipsec_init __P((void));
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void ippr_ipsec_fini __P((void));
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int ippr_ipsec_new __P((fr_info_t *, ap_session_t *, nat_t *));
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void ippr_ipsec_del __P((ap_session_t *));
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int ippr_ipsec_inout __P((fr_info_t *, ap_session_t *, nat_t *));
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int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
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static frentry_t ipsecfr;
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static ipftq_t *ipsecnattqe;
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static ipftq_t *ipsecstatetqe;
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static char ipsec_buffer[1500];
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int ipsec_proxy_init = 0;
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int ipsec_proxy_ttl = 60;
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/*
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* IPSec application proxy initialization.
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*/
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int ippr_ipsec_init()
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{
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bzero((char *)&ipsecfr, sizeof(ipsecfr));
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ipsecfr.fr_ref = 1;
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ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
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MUTEX_INIT(&ipsecfr.fr_lock, "IPsec proxy rule lock");
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ipsec_proxy_init = 1;
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ipsecnattqe = fr_addtimeoutqueue(&nat_utqe, ipsec_proxy_ttl);
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if (ipsecnattqe == NULL)
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return -1;
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ipsecstatetqe = fr_addtimeoutqueue(&ips_utqe, ipsec_proxy_ttl);
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if (ipsecstatetqe == NULL) {
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if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
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fr_freetimeoutqueue(ipsecnattqe);
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ipsecnattqe = NULL;
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return -1;
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}
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ipsecnattqe->ifq_flags |= IFQF_PROXY;
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ipsecstatetqe->ifq_flags |= IFQF_PROXY;
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ipsecfr.fr_age[0] = ipsec_proxy_ttl;
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ipsecfr.fr_age[1] = ipsec_proxy_ttl;
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return 0;
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}
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void ippr_ipsec_fini()
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{
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if (ipsecnattqe != NULL) {
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if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
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fr_freetimeoutqueue(ipsecnattqe);
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}
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ipsecnattqe = NULL;
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if (ipsecstatetqe != NULL) {
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if (fr_deletetimeoutqueue(ipsecstatetqe) == 0)
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fr_freetimeoutqueue(ipsecstatetqe);
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}
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ipsecstatetqe = NULL;
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if (ipsec_proxy_init == 1) {
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MUTEX_DESTROY(&ipsecfr.fr_lock);
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ipsec_proxy_init = 0;
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}
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}
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/*
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* Setup for a new IPSEC proxy.
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*/
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int ippr_ipsec_new(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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ipsec_pxy_t *ipsec;
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fr_info_t fi;
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ipnat_t *ipn;
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char *ptr;
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int p, off, dlen, ttl;
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mb_t *m;
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ip_t *ip;
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bzero(ipsec_buffer, sizeof(ipsec_buffer));
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off = fin->fin_hlen + sizeof(udphdr_t);
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ip = fin->fin_ip;
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m = fin->fin_m;
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dlen = M_LEN(m) - off;
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if (dlen < 16)
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return -1;
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COPYDATA(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
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if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
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ip->ip_dst) != NULL)
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return -1;
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aps->aps_psiz = sizeof(*ipsec);
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KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
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if (aps->aps_data == NULL)
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return -1;
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ipsec = aps->aps_data;
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bzero((char *)ipsec, sizeof(*ipsec));
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/*
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* Create NAT rule against which the tunnel/transport mapping is
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* created. This is required because the current NAT rule does not
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* describe ESP but UDP instead.
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*/
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ipn = &ipsec->ipsc_rule;
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ttl = IPF_TTLVAL(ipsecnattqe->ifq_ttl);
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ipn->in_tqehead[0] = fr_addtimeoutqueue(&nat_utqe, ttl);
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ipn->in_tqehead[1] = fr_addtimeoutqueue(&nat_utqe, ttl);
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ipn->in_ifps[0] = fin->fin_ifp;
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ipn->in_apr = NULL;
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ipn->in_use = 1;
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ipn->in_hits = 1;
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ipn->in_nip = ntohl(nat->nat_outip.s_addr);
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ipn->in_ippip = 1;
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ipn->in_inip = nat->nat_inip.s_addr;
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ipn->in_inmsk = 0xffffffff;
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ipn->in_outip = fin->fin_saddr;
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ipn->in_outmsk = nat->nat_outip.s_addr;
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ipn->in_srcip = fin->fin_saddr;
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ipn->in_srcmsk = 0xffffffff;
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ipn->in_redir = NAT_MAP;
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bcopy(nat->nat_ptr->in_ifnames[0], ipn->in_ifnames[0],
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sizeof(ipn->in_ifnames[0]));
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ipn->in_p = IPPROTO_ESP;
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bcopy((char *)fin, (char *)&fi, sizeof(fi));
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fi.fin_state = NULL;
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fi.fin_nat = NULL;
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fi.fin_fi.fi_p = IPPROTO_ESP;
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fi.fin_fr = &ipsecfr;
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fi.fin_data[0] = 0;
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fi.fin_data[1] = 0;
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p = ip->ip_p;
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ip->ip_p = IPPROTO_ESP;
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fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
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fi.fin_flx |= FI_IGNORE;
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ptr = ipsec_buffer;
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bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
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ptr += sizeof(ipsec_cookie_t);
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bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
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/*
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* The responder cookie should only be non-zero if the initiator
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* cookie is non-zero. Therefore, it is safe to assume(!) that the
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* cookies are both set after copying if the responder is non-zero.
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*/
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if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
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ipsec->ipsc_rckset = 1;
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ipsec->ipsc_nat = nat_new(&fi, ipn, &ipsec->ipsc_nat,
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NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
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if (ipsec->ipsc_nat != NULL) {
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(void) nat_proto(&fi, ipsec->ipsc_nat, 0);
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nat_update(&fi, ipsec->ipsc_nat, ipn);
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fi.fin_data[0] = 0;
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fi.fin_data[1] = 0;
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ipsec->ipsc_state = fr_addstate(&fi, &ipsec->ipsc_state,
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SI_WILDP);
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if (fi.fin_state != NULL)
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fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
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}
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ip->ip_p = p & 0xff;
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return 0;
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}
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/*
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* For outgoing IKE packets. refresh timeouts for NAT & state entries, if
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* we can. If they have disappeared, recreate them.
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*/
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int ippr_ipsec_inout(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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ipsec_pxy_t *ipsec;
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fr_info_t fi;
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ip_t *ip;
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int p;
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if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
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return 0;
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if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
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return 0;
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ipsec = aps->aps_data;
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if (ipsec != NULL) {
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ip = fin->fin_ip;
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p = ip->ip_p;
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if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
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bcopy((char *)fin, (char *)&fi, sizeof(fi));
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fi.fin_state = NULL;
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fi.fin_nat = NULL;
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fi.fin_fi.fi_p = IPPROTO_ESP;
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fi.fin_fr = &ipsecfr;
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fi.fin_data[0] = 0;
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fi.fin_data[1] = 0;
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ip->ip_p = IPPROTO_ESP;
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fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
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fi.fin_flx |= FI_IGNORE;
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}
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/*
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* Update NAT timeout/create NAT if missing.
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*/
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if (ipsec->ipsc_nat != NULL)
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fr_queueback(&ipsec->ipsc_nat->nat_tqe);
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else {
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ipsec->ipsc_nat = nat_new(&fi, &ipsec->ipsc_rule,
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&ipsec->ipsc_nat,
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NAT_SLAVE|SI_WILDP,
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nat->nat_dir);
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if (ipsec->ipsc_nat != NULL) {
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(void) nat_proto(&fi, ipsec->ipsc_nat, 0);
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nat_update(&fi, ipsec->ipsc_nat,
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&ipsec->ipsc_rule);
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}
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}
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/*
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* Update state timeout/create state if missing.
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*/
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READ_ENTER(&ipf_state);
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if (ipsec->ipsc_state != NULL) {
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fr_queueback(&ipsec->ipsc_state->is_sti);
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ipsec->ipsc_state->is_die = nat->nat_age;
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RWLOCK_EXIT(&ipf_state);
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} else {
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RWLOCK_EXIT(&ipf_state);
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fi.fin_data[0] = 0;
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fi.fin_data[1] = 0;
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ipsec->ipsc_state = fr_addstate(&fi,
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&ipsec->ipsc_state,
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SI_WILDP);
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if (fi.fin_state != NULL)
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fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
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}
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ip->ip_p = p;
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}
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return 0;
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}
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/*
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* This extends the NAT matching to be based on the cookies associated with
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* a session and found at the front of IKE packets. The cookies are always
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* in the same order (not reversed depending on packet flow direction as with
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* UDP/TCP port numbers).
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*/
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int ippr_ipsec_match(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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ipsec_pxy_t *ipsec;
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u_32_t cookies[4];
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mb_t *m;
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int off;
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nat = nat; /* LINT */
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if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
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return -1;
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ipsec = aps->aps_data;
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off = fin->fin_hlen + sizeof(udphdr_t);
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m = fin->fin_m;
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COPYDATA(m, off, sizeof(cookies), (char *)cookies);
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if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
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(cookies[1] != ipsec->ipsc_icookie[1]))
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return -1;
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if (ipsec->ipsc_rckset == 0) {
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if ((cookies[2]|cookies[3]) == 0) {
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return 0;
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}
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ipsec->ipsc_rckset = 1;
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ipsec->ipsc_rcookie[0] = cookies[2];
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ipsec->ipsc_rcookie[1] = cookies[3];
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return 0;
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}
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if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
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(cookies[3] != ipsec->ipsc_rcookie[1]))
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return -1;
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return 0;
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}
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/*
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* clean up after ourselves.
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*/
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void ippr_ipsec_del(aps)
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ap_session_t *aps;
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{
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ipsec_pxy_t *ipsec;
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ipsec = aps->aps_data;
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if (ipsec != NULL) {
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/*
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* Don't bother changing any of the NAT structure details,
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* *_del() is on a callback from aps_free(), from nat_delete()
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*/
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READ_ENTER(&ipf_state);
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if (ipsec->ipsc_state != NULL) {
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ipsec->ipsc_state->is_die = fr_ticks + 1;
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ipsec->ipsc_state->is_me = NULL;
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fr_queuefront(&ipsec->ipsc_state->is_sti);
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}
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RWLOCK_EXIT(&ipf_state);
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ipsec->ipsc_state = NULL;
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ipsec->ipsc_nat = NULL;
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}
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}
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