237 lines
5.0 KiB
C
237 lines
5.0 KiB
C
/* $NetBSD$ */
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/*
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* Copyright (C) 1998-2003 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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* Id: ip_rcmd_pxy.c,v 1.41.2.4 2005/02/04 10:22:55 darrenr Exp
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*
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* Simple RCMD transparent proxy for in-kernel use. For use with the NAT
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* code.
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*/
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#define IPF_RCMD_PROXY
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int ippr_rcmd_init __P((void));
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void ippr_rcmd_fini __P((void));
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int ippr_rcmd_new __P((fr_info_t *, ap_session_t *, nat_t *));
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int ippr_rcmd_out __P((fr_info_t *, ap_session_t *, nat_t *));
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int ippr_rcmd_in __P((fr_info_t *, ap_session_t *, nat_t *));
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u_short ipf_rcmd_atoi __P((char *));
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int ippr_rcmd_portmsg __P((fr_info_t *, ap_session_t *, nat_t *));
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static frentry_t rcmdfr;
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int rcmd_proxy_init = 0;
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/*
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* RCMD application proxy initialization.
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*/
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int ippr_rcmd_init()
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{
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bzero((char *)&rcmdfr, sizeof(rcmdfr));
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rcmdfr.fr_ref = 1;
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rcmdfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
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MUTEX_INIT(&rcmdfr.fr_lock, "RCMD proxy rule lock");
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rcmd_proxy_init = 1;
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return 0;
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}
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void ippr_rcmd_fini()
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{
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if (rcmd_proxy_init == 1) {
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MUTEX_DESTROY(&rcmdfr.fr_lock);
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rcmd_proxy_init = 0;
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}
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}
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/*
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* Setup for a new RCMD proxy.
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*/
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int ippr_rcmd_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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tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
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fin = fin; /* LINT */
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nat = nat; /* LINT */
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aps->aps_psiz = sizeof(u_32_t);
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KMALLOCS(aps->aps_data, u_32_t *, sizeof(u_32_t));
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if (aps->aps_data == NULL) {
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#ifdef IP_RCMD_PROXY_DEBUG
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printf("ippr_rcmd_new:KMALLOCS(%d) failed\n", sizeof(u_32_t));
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#endif
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return -1;
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}
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*(u_32_t *)aps->aps_data = 0;
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aps->aps_sport = tcp->th_sport;
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aps->aps_dport = tcp->th_dport;
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return 0;
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}
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/*
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* ipf_rcmd_atoi - implement a simple version of atoi
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*/
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u_short ipf_rcmd_atoi(ptr)
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char *ptr;
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{
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register char *s = ptr, c;
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register u_short i = 0;
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while (((c = *s++) != '\0') && ISDIGIT(c)) {
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i *= 10;
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i += c - '0';
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}
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return i;
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}
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int ippr_rcmd_portmsg(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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tcphdr_t *tcp, tcph, *tcp2 = &tcph;
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struct in_addr swip, swip2;
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int off, dlen, nflags;
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char portbuf[8], *s;
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fr_info_t fi;
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u_short sp;
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nat_t *nat2;
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ip_t *ip;
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mb_t *m;
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tcp = (tcphdr_t *)fin->fin_dp;
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if (tcp->th_flags & TH_SYN) {
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*(u_32_t *)aps->aps_data = htonl(ntohl(tcp->th_seq) + 1);
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return 0;
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}
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if ((*(u_32_t *)aps->aps_data != 0) &&
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(tcp->th_seq != *(u_32_t *)aps->aps_data))
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return 0;
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m = fin->fin_m;
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ip = fin->fin_ip;
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off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
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#ifdef __sgi
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dlen = fin->fin_plen - off;
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#else
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dlen = MSGDSIZE(m) - off;
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#endif
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if (dlen <= 0)
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return 0;
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bzero(portbuf, sizeof(portbuf));
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COPYDATA(m, off, MIN(sizeof(portbuf), dlen), portbuf);
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portbuf[sizeof(portbuf) - 1] = '\0';
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s = portbuf;
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sp = ipf_rcmd_atoi(s);
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if (sp == 0) {
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#ifdef IP_RCMD_PROXY_DEBUG
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printf("ippr_rcmd_portmsg:sp == 0 dlen %d [%s]\n",
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dlen, portbuf);
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#endif
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return 0;
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}
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/*
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* Add skeleton NAT entry for connection which will come back the
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* other way.
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*/
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bcopy((char *)fin, (char *)&fi, sizeof(fi));
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fi.fin_flx |= FI_IGNORE;
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fi.fin_data[0] = sp;
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fi.fin_data[1] = 0;
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if (nat->nat_dir == NAT_OUTBOUND)
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nat2 = nat_outlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
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nat->nat_inip, nat->nat_oip);
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else
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nat2 = nat_inlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
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nat->nat_inip, nat->nat_oip);
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if (nat2 == NULL) {
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int slen;
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slen = ip->ip_len;
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ip->ip_len = fin->fin_hlen + sizeof(*tcp);
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bzero((char *)tcp2, sizeof(*tcp2));
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tcp2->th_win = htons(8192);
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tcp2->th_sport = htons(sp);
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tcp2->th_dport = 0; /* XXX - don't specify remote port */
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TCP_OFF_A(tcp2, 5);
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tcp2->th_flags = TH_SYN;
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fi.fin_dp = (char *)tcp2;
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fi.fin_fr = &rcmdfr;
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fi.fin_dlen = sizeof(*tcp2);
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fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
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fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
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nflags = NAT_SLAVE|IPN_TCP|SI_W_DPORT;
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swip = ip->ip_src;
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swip2 = ip->ip_dst;
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if (nat->nat_dir == NAT_OUTBOUND) {
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fi.fin_fi.fi_saddr = nat->nat_inip.s_addr;
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ip->ip_src = nat->nat_inip;
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} else {
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fi.fin_fi.fi_saddr = nat->nat_oip.s_addr;
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ip->ip_src = nat->nat_oip;
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nflags |= NAT_NOTRULEPORT;
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}
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nat2 = nat_new(&fi, nat->nat_ptr, NULL, nflags, nat->nat_dir);
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if (nat2 != NULL) {
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(void) nat_proto(&fi, nat2, IPN_TCP);
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nat_update(&fi, nat2, nat2->nat_ptr);
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fi.fin_ifp = NULL;
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if (nat->nat_dir == NAT_INBOUND) {
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fi.fin_fi.fi_daddr = nat->nat_inip.s_addr;
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ip->ip_dst = nat->nat_inip;
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}
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(void) fr_addstate(&fi, &nat2->nat_state, SI_W_DPORT);
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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_len = slen;
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ip->ip_src = swip;
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ip->ip_dst = swip2;
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}
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return 0;
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}
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int ippr_rcmd_out(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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if (nat->nat_dir == NAT_OUTBOUND)
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return ippr_rcmd_portmsg(fin, aps, nat);
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return 0;
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}
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int ippr_rcmd_in(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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if (nat->nat_dir == NAT_INBOUND)
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return ippr_rcmd_portmsg(fin, aps, nat);
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return 0;
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}
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