394 lines
8.2 KiB
C
394 lines
8.2 KiB
C
/* $NetBSD: ip_proxy.c,v 1.20 2000/03/30 13:25:03 augustss Exp $ */
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/*
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* Copyright (C) 1997-1998 by Darren Reed.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that this notice is preserved and due credit is given
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* to the original author and the contributors.
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*/
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#if !defined(lint)
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#if defined(__NetBSD__)
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static const char rcsid[] = "$NetBSD: ip_proxy.c,v 1.20 2000/03/30 13:25:03 augustss Exp $";
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#else
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static const char rcsid[] = "@(#)Id: ip_proxy.c,v 2.2.2.1 1999/09/19 12:18:19 darrenr Exp ";
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#endif
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#endif
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#if defined(__FreeBSD__) && defined(KERNEL) && !defined(_KERNEL)
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# define _KERNEL
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#endif
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#include <sys/errno.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/file.h>
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#if !defined(__FreeBSD_version)
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# include <sys/ioctl.h>
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#endif
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#include <sys/fcntl.h>
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#include <sys/uio.h>
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#if !defined(_KERNEL) && !defined(KERNEL)
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# include <stdio.h>
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# include <string.h>
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# include <stdlib.h>
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#endif
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#ifndef linux
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# include <sys/protosw.h>
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#endif
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#include <sys/socket.h>
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#if defined(_KERNEL)
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# if !defined(linux)
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# include <sys/systm.h>
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# else
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# include <linux/string.h>
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# endif
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#endif
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#if !defined(__SVR4) && !defined(__svr4__)
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# ifndef linux
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# include <sys/mbuf.h>
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# endif
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#else
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# include <sys/byteorder.h>
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# ifdef _KERNEL
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# include <sys/dditypes.h>
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# endif
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# include <sys/stream.h>
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# include <sys/kmem.h>
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#endif
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#if __FreeBSD__ > 2
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# include <sys/queue.h>
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#endif
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#include <net/if.h>
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#ifdef sun
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# include <net/af.h>
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#endif
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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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#ifndef linux
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# include <netinet/ip_var.h>
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#endif
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#include <netinet/tcp.h>
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#include <netinet/udp.h>
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#include <netinet/ip_icmp.h>
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#include "netinet/ip_compat.h"
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#include <netinet/tcpip.h>
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#include "netinet/ip_fil.h"
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#include "netinet/ip_proxy.h"
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#include "netinet/ip_nat.h"
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#include "netinet/ip_state.h"
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#if (__FreeBSD_version >= 300000)
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# include <sys/malloc.h>
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#endif
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#ifndef MIN
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#define MIN(a,b) (((a)<(b))?(a):(b))
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#endif
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static ap_session_t *appr_new_session __P((aproxy_t *, ip_t *,
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fr_info_t *, nat_t *));
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static int appr_fixseqack __P((fr_info_t *, ip_t *, ap_session_t *, int ));
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#define AP_SESS_SIZE 53
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#if defined(_KERNEL) && !defined(linux)
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#include "netinet/ip_ftp_pxy.c"
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#include "netinet/ip_rcmd_pxy.c"
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#include "netinet/ip_raudio_pxy.c"
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#endif
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ap_session_t *ap_sess_tab[AP_SESS_SIZE];
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ap_session_t *ap_sess_list = NULL;
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aproxy_t ap_proxies[] = {
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#ifdef IPF_FTP_PROXY
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{ "ftp", (char)IPPROTO_TCP, 0, 0, ippr_ftp_init, NULL,
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ippr_ftp_in, ippr_ftp_out },
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#endif
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#ifdef IPF_RCMD_PROXY
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{ "rcmd", (char)IPPROTO_TCP, 0, 0, ippr_rcmd_init, ippr_rcmd_new,
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NULL, ippr_rcmd_out },
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#endif
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#ifdef IPF_RAUDIO_PROXY
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{ "raudio", (char)IPPROTO_TCP, 0, 0, ippr_raudio_init,
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ippr_raudio_new, ippr_raudio_in, ippr_raudio_out },
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#endif
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{ "", '\0', 0, 0, NULL, NULL }
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};
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int appr_ok(ip, tcp, nat)
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ip_t *ip;
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tcphdr_t *tcp;
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ipnat_t *nat;
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{
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aproxy_t *apr = nat->in_apr;
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u_short dport = nat->in_dport;
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if (!apr || (apr->apr_flags & APR_DELETE) ||
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(ip->ip_p != apr->apr_p))
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return 0;
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if ((tcp && (tcp->th_dport != dport)) || (!tcp && dport))
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return 0;
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return 1;
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}
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/*
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* Allocate a new application proxy structure and fill it in with the
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* relevant details. call the init function once complete, prior to
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* returning.
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*/
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static ap_session_t *appr_new_session(apr, ip, fin, nat)
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aproxy_t *apr;
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ip_t *ip;
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fr_info_t *fin;
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nat_t *nat;
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{
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ap_session_t *aps;
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if (!apr || (apr->apr_flags & APR_DELETE) || (ip->ip_p != apr->apr_p))
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return NULL;
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KMALLOC(aps, ap_session_t *);
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if (!aps)
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return NULL;
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bzero((char *)aps, sizeof(*aps));
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aps->aps_next = ap_sess_list;
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aps->aps_p = ip->ip_p;
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aps->aps_data = NULL;
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aps->aps_apr = apr;
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aps->aps_psiz = 0;
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ap_sess_list = aps;
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aps->aps_nat = nat;
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nat->nat_aps = aps;
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if (apr->apr_new != NULL)
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(void) (*apr->apr_new)(fin, ip, aps, nat);
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return aps;
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}
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/*
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* check to see if a packet should be passed through an active proxy routine
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* if one has been setup for it.
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*/
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int appr_check(ip, fin, nat)
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ip_t *ip;
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fr_info_t *fin;
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nat_t *nat;
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{
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ap_session_t *aps;
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aproxy_t *apr;
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tcphdr_t *tcp = NULL;
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u_32_t sum;
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int err;
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if (nat->nat_aps == NULL)
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nat->nat_aps = appr_new_session(nat->nat_ptr->in_apr, ip,
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fin, nat);
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aps = nat->nat_aps;
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if ((aps != NULL) && (aps->aps_p == ip->ip_p)) {
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if (ip->ip_p == IPPROTO_TCP) {
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tcp = (tcphdr_t *)fin->fin_dp;
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/*
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* verify that the checksum is correct. If not, then
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* don't do anything with this packet.
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*/
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#if SOLARIS && defined(_KERNEL)
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sum = fr_tcpsum(fin->fin_qfm, ip, tcp);
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#else
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sum = fr_tcpsum(*(mb_t **)fin->fin_mp, ip, tcp);
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#endif
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if (sum != tcp->th_sum) {
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frstats[fin->fin_out].fr_tcpbad++;
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return -1;
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}
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}
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apr = aps->aps_apr;
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err = 0;
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if (fin->fin_out != 0) {
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if (apr->apr_outpkt != NULL)
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err = (*apr->apr_outpkt)(fin, ip, aps, nat);
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} else {
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if (apr->apr_inpkt != NULL)
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err = (*apr->apr_inpkt)(fin, ip, aps, nat);
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}
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if (tcp != NULL) {
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err = appr_fixseqack(fin, ip, aps, err);
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#if SOLARIS && defined(_KERNEL)
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tcp->th_sum = fr_tcpsum(fin->fin_qfm, ip, tcp);
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#else
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tcp->th_sum = fr_tcpsum(*(mb_t **)fin->fin_mp, ip, tcp);
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#endif
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}
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aps->aps_bytes += ip->ip_len;
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aps->aps_pkts++;
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return 2;
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}
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return -1;
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}
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aproxy_t *appr_match(pr, name)
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u_int pr;
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char *name;
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{
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aproxy_t *ap;
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for (ap = ap_proxies; ap->apr_p; ap++)
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if ((ap->apr_p == pr) &&
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!strncmp(name, ap->apr_label, sizeof(ap->apr_label))) {
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ap->apr_ref++;
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return ap;
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}
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return NULL;
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}
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void appr_free(ap)
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aproxy_t *ap;
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{
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ap->apr_ref--;
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}
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void aps_free(aps)
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ap_session_t *aps;
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{
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ap_session_t *a, **ap;
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if (!aps)
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return;
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for (ap = &ap_sess_list; (a = *ap); ap = &a->aps_next)
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if (a == aps) {
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*ap = a->aps_next;
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break;
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}
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if (a) {
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if ((aps->aps_data != NULL) && (aps->aps_psiz != 0))
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KFREES(aps->aps_data, aps->aps_psiz);
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KFREE(aps);
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}
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}
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static int appr_fixseqack(fin, ip, aps, inc)
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fr_info_t *fin;
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ip_t *ip;
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ap_session_t *aps;
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int inc;
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{
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int sel, ch = 0, out, nlen;
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u_32_t seq1, seq2;
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tcphdr_t *tcp;
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tcp = (tcphdr_t *)fin->fin_dp;
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out = fin->fin_out;
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nlen = ip->ip_len;
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nlen -= (ip->ip_hl << 2) + (tcp->th_off << 2);
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if (out != 0) {
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seq1 = (u_32_t)ntohl(tcp->th_seq);
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sel = aps->aps_sel[out];
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/* switch to other set ? */
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if ((aps->aps_seqmin[!sel] > aps->aps_seqmin[sel]) &&
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(seq1 > aps->aps_seqmin[!sel]))
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sel = aps->aps_sel[out] = !sel;
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if (aps->aps_seqoff[sel]) {
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seq2 = aps->aps_seqmin[sel] - aps->aps_seqoff[sel];
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if (seq1 > seq2) {
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seq2 = aps->aps_seqoff[sel];
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seq1 += seq2;
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tcp->th_seq = htonl(seq1);
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ch = 1;
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}
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}
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if (inc && (seq1 > aps->aps_seqmin[!sel])) {
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aps->aps_seqmin[!sel] = seq1 + nlen - 1;
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aps->aps_seqoff[!sel] = aps->aps_seqoff[sel] + inc;
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}
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/***/
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seq1 = ntohl(tcp->th_ack);
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sel = aps->aps_sel[1 - out];
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/* switch to other set ? */
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if ((aps->aps_ackmin[!sel] > aps->aps_ackmin[sel]) &&
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(seq1 > aps->aps_ackmin[!sel]))
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sel = aps->aps_sel[1 - out] = !sel;
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if (aps->aps_ackoff[sel] && (seq1 > aps->aps_ackmin[sel])) {
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seq2 = aps->aps_ackoff[sel];
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tcp->th_ack = htonl(seq1 - seq2);
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ch = 1;
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}
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} else {
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seq1 = ntohl(tcp->th_seq);
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sel = aps->aps_sel[out];
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/* switch to other set ? */
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if ((aps->aps_ackmin[!sel] > aps->aps_ackmin[sel]) &&
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(seq1 > aps->aps_ackmin[!sel]))
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sel = aps->aps_sel[out] = !sel;
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if (aps->aps_ackoff[sel]) {
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seq2 = aps->aps_ackmin[sel] -
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aps->aps_ackoff[sel];
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if (seq1 > seq2) {
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seq2 = aps->aps_ackoff[sel];
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seq1 += seq2;
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tcp->th_seq = htonl(seq1);
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ch = 1;
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}
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}
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if (inc && (seq1 > aps->aps_ackmin[!sel])) {
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aps->aps_ackmin[!sel] = seq1 + nlen - 1;
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aps->aps_ackoff[!sel] = aps->aps_ackoff[sel] + inc;
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}
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/***/
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seq1 = ntohl(tcp->th_ack);
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sel = aps->aps_sel[1 - out];
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/* switch to other set ? */
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if ((aps->aps_seqmin[!sel] > aps->aps_seqmin[sel]) &&
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(seq1 > aps->aps_seqmin[!sel]))
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sel = aps->aps_sel[1 - out] = !sel;
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if (aps->aps_seqoff[sel] && (seq1 > aps->aps_seqmin[sel])) {
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seq2 = aps->aps_seqoff[sel];
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tcp->th_ack = htonl(seq1 - seq2);
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ch = 1;
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}
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}
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return ch ? 2 : 0;
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}
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int appr_init()
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{
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aproxy_t *ap;
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int err = 0;
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for (ap = ap_proxies; ap->apr_p; ap++) {
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err = (*ap->apr_init)();
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if (err != 0)
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break;
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}
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return err;
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}
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