1877 lines
44 KiB
C
1877 lines
44 KiB
C
/* $NetBSD: ip_state.c,v 1.28 2001/02/05 10:42:44 chs Exp $ */
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/*
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* Copyright (C) 1995-2000 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_state.c,v 1.28 2001/02/05 10:42:44 chs Exp $";
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#else
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static const char sccsid[] = "@(#)ip_state.c 1.8 6/5/96 (C) 1993-2000 Darren Reed";
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static const char rcsid[] = "@(#)Id: ip_state.c,v 2.30.2.17 2000/08/08 16:01:03 darrenr Exp";
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#endif
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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/file.h>
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#if defined(__NetBSD__) && (NetBSD >= 199905) && !defined(IPFILTER_LKM) && \
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defined(_KERNEL) && !defined(_LKM)
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# include "opt_ipfilter_log.h"
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#endif
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#if defined(_KERNEL) && defined(__FreeBSD_version) && \
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(__FreeBSD_version >= 400000) && !defined(KLD_MODULE)
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#include "opt_inet6.h"
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#endif
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#if !defined(_KERNEL) && !defined(KERNEL) && !defined(__KERNEL__)
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# include <stdio.h>
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# include <stdlib.h>
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# include <string.h>
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#else
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# ifdef linux
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# include <linux/kernel.h>
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# include <linux/module.h>
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# endif
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#endif
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#if (defined(KERNEL) || defined(_KERNEL)) && (__FreeBSD_version >= 220000)
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# include <sys/filio.h>
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# include <sys/fcntl.h>
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# if (__FreeBSD_version >= 300000) && !defined(IPFILTER_LKM)
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# include "opt_ipfilter.h"
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# endif
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#else
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# include <sys/ioctl.h>
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#endif
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#include <sys/time.h>
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#include <sys/uio.h>
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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) || defined(KERNEL)) && !defined(linux)
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# include <sys/systm.h>
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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/filio.h>
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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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#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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#include <netinet/tcp.h>
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#ifndef linux
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# include <netinet/ip_var.h>
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# include <netinet/tcp_fsm.h>
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#endif
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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_nat.h"
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#include "netinet/ip_frag.h"
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#include "netinet/ip_proxy.h"
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#include "netinet/ip_state.h"
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#ifdef USE_INET6
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#include <netinet/icmp6.h>
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#endif
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#if (__FreeBSD_version >= 300000)
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# include <sys/malloc.h>
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# if (defined(_KERNEL) || defined(KERNEL)) && !defined(IPFILTER_LKM)
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# include <sys/libkern.h>
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# include <sys/systm.h>
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# endif
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#endif
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#define TCP_CLOSE (TH_FIN|TH_RST)
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static ipstate_t **ips_table = NULL;
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static ipstate_t *ips_list = NULL;
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static int ips_num = 0;
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static ips_stat_t ips_stats;
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#if (SOLARIS || defined(__sgi)) && defined(_KERNEL)
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extern KRWLOCK_T ipf_state, ipf_mutex;
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extern kmutex_t ipf_rw;
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#endif
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#ifdef USE_INET6
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static frentry_t *fr_checkicmp6matchingstate __P((ip6_t *, fr_info_t *));
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#endif
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static int fr_matchsrcdst __P((ipstate_t *, union i6addr, union i6addr,
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fr_info_t *, tcphdr_t *));
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static frentry_t *fr_checkicmpmatchingstate __P((ip_t *, fr_info_t *));
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static int fr_matchicmpqueryreply __P((int, ipstate_t *, icmphdr_t *));
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static int fr_state_flush __P((int));
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static ips_stat_t *fr_statetstats __P((void));
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static void fr_delstate __P((ipstate_t *));
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static int fr_state_remove __P((caddr_t));
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int fr_stputent __P((caddr_t));
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int fr_stgetent __P((caddr_t));
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void fr_stinsert __P((ipstate_t *));
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#define FIVE_DAYS (2 * 5 * 86400) /* 5 days: half closed session */
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#define TCP_MSL 240 /* 2 minutes */
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u_long fr_tcpidletimeout = FIVE_DAYS,
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fr_tcpclosewait = 2 * TCP_MSL,
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fr_tcplastack = 2 * TCP_MSL,
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fr_tcptimeout = 2 * TCP_MSL,
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fr_tcpclosed = 1,
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fr_udptimeout = 240,
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fr_icmptimeout = 120;
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int fr_statemax = IPSTATE_MAX,
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fr_statesize = IPSTATE_SIZE;
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int fr_state_doflush = 0,
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fr_state_lock = 0;
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static int icmpreplytype4[ICMP_MAXTYPE + 1];
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int fr_stateinit()
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{
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int i;
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KMALLOCS(ips_table, ipstate_t **, fr_statesize * sizeof(ipstate_t *));
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if (ips_table != NULL)
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bzero((char *)ips_table, fr_statesize * sizeof(ipstate_t *));
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else
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return -1;
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/* fill icmp reply type table */
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for (i = 0; i <= ICMP_MAXTYPE; i++)
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icmpreplytype4[i] = -1;
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icmpreplytype4[ICMP_ECHO] = ICMP_ECHOREPLY;
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icmpreplytype4[ICMP_TSTAMP] = ICMP_TSTAMPREPLY;
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icmpreplytype4[ICMP_IREQ] = ICMP_IREQREPLY;
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icmpreplytype4[ICMP_MASKREQ] = ICMP_MASKREPLY;
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return 0;
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}
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static ips_stat_t *fr_statetstats()
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{
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ips_stats.iss_active = ips_num;
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ips_stats.iss_table = ips_table;
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ips_stats.iss_list = ips_list;
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return &ips_stats;
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}
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/*
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* flush state tables. two actions currently defined:
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* which == 0 : flush all state table entries
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* which == 1 : flush TCP connections which have started to close but are
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* stuck for some reason.
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*/
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static int fr_state_flush(which)
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int which;
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{
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register ipstate_t *is, **isp;
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#if defined(_KERNEL) && !SOLARIS
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int s;
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#endif
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int delete, removed = 0;
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SPL_NET(s);
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for (isp = &ips_list; (is = *isp); ) {
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delete = 0;
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switch (which)
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{
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case 0 :
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delete = 1;
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break;
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case 1 :
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if (is->is_p != IPPROTO_TCP)
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break;
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if ((is->is_state[0] != TCPS_ESTABLISHED) ||
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(is->is_state[1] != TCPS_ESTABLISHED))
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delete = 1;
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break;
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}
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if (delete) {
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if (is->is_p == IPPROTO_TCP)
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ips_stats.iss_fin++;
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else
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ips_stats.iss_expire++;
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#ifdef IPFILTER_LOG
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ipstate_log(is, ISL_FLUSH);
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#endif
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fr_delstate(is);
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removed++;
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} else
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isp = &is->is_next;
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}
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SPL_X(s);
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return removed;
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}
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static int fr_state_remove(data)
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caddr_t data;
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{
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ipstate_t *sp, st;
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int error;
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sp = &st;
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error = IRCOPYPTR(data, (caddr_t)&st, sizeof(st));
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if (error)
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return EFAULT;
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for (sp = ips_list; sp; sp = sp->is_next)
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if ((sp->is_p == st.is_p) && (sp->is_v == st.is_v) &&
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!bcmp(&sp->is_src, &st.is_src, sizeof(st.is_src)) &&
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!bcmp(&sp->is_dst, &st.is_src, sizeof(st.is_dst)) &&
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!bcmp(&sp->is_ps, &st.is_ps, sizeof(st.is_ps))) {
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WRITE_ENTER(&ipf_state);
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#ifdef IPFILTER_LOG
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ipstate_log(sp, ISL_REMOVE);
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#endif
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fr_delstate(sp);
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RWLOCK_EXIT(&ipf_state);
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return 0;
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}
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return ESRCH;
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}
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int fr_state_ioctl(data, cmd, mode)
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caddr_t data;
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#if defined(__NetBSD__) || defined(__OpenBSD__)
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u_long cmd;
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#else
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int cmd;
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#endif
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int mode;
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{
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int arg, ret, error = 0;
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switch (cmd)
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{
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case SIOCDELST :
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error = fr_state_remove(data);
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break;
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case SIOCIPFFL :
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error = IRCOPY(data, (caddr_t)&arg, sizeof(arg));
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if (error)
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break;
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if (arg == 0 || arg == 1) {
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WRITE_ENTER(&ipf_state);
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ret = fr_state_flush(arg);
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RWLOCK_EXIT(&ipf_state);
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error = IWCOPY((caddr_t)&ret, data, sizeof(ret));
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} else
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error = EINVAL;
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break;
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#ifdef IPFILTER_LOG
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case SIOCIPFFB :
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if (!(mode & FWRITE))
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error = EPERM;
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else {
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int tmp;
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tmp = ipflog_clear(IPL_LOGSTATE);
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IWCOPY((char *)&tmp, data, sizeof(tmp));
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}
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break;
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#endif
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case SIOCGETFS :
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error = IWCOPYPTR((caddr_t)fr_statetstats(), data,
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sizeof(ips_stat_t));
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break;
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case FIONREAD :
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#ifdef IPFILTER_LOG
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error = IWCOPY((caddr_t)&iplused[IPL_LOGSTATE], (caddr_t)data,
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sizeof(iplused[IPL_LOGSTATE]));
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#endif
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break;
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case SIOCSTLCK :
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error = fr_lock(data, &fr_state_lock);
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break;
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case SIOCSTPUT :
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if (!fr_state_lock) {
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error = EACCES;
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break;
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}
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error = fr_stputent(data);
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break;
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case SIOCSTGET :
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if (!fr_state_lock) {
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error = EACCES;
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break;
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}
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error = fr_stgetent(data);
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break;
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default :
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error = EINVAL;
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break;
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}
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return error;
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}
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int fr_stgetent(data)
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caddr_t data;
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{
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register ipstate_t *is, *isn;
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ipstate_save_t ips, *ipsp;
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int error;
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error = IRCOPY(data, (caddr_t)&ipsp, sizeof(ipsp));
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if (error)
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return EFAULT;
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error = IRCOPY((caddr_t)ipsp, (caddr_t)&ips, sizeof(ips));
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if (error)
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return EFAULT;
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isn = ips.ips_next;
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if (!isn) {
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isn = ips_list;
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if (isn == NULL) {
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if (ips.ips_next == NULL)
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return ENOENT;
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return 0;
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}
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} else {
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/*
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* Make sure the pointer we're copying from exists in the
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* current list of entries. Security precaution to prevent
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* copying of random kernel data.
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*/
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for (is = ips_list; is; is = is->is_next)
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if (is == isn)
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break;
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if (!is)
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return ESRCH;
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}
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ips.ips_next = isn->is_next;
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bcopy((char *)isn, (char *)&ips.ips_is, sizeof(ips.ips_is));
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if (isn->is_rule)
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bcopy((char *)isn->is_rule, (char *)&ips.ips_fr,
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sizeof(ips.ips_fr));
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error = IWCOPY((caddr_t)&ips, ipsp, sizeof(ips));
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if (error)
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error = EFAULT;
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return error;
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}
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int fr_stputent(data)
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caddr_t data;
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{
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register ipstate_t *is, *isn;
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ipstate_save_t ips, *ipsp;
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int error, out;
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frentry_t *fr;
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error = IRCOPY(data, (caddr_t)&ipsp, sizeof(ipsp));
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if (error)
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return EFAULT;
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error = IRCOPY((caddr_t)ipsp, (caddr_t)&ips, sizeof(ips));
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if (error)
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return EFAULT;
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KMALLOC(isn, ipstate_t *);
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if (isn == NULL)
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return ENOMEM;
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bcopy((char *)&ips.ips_is, (char *)isn, sizeof(*isn));
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fr = isn->is_rule;
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if (fr != NULL) {
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if (isn->is_flags & FI_NEWFR) {
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KMALLOC(fr, frentry_t *);
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if (fr == NULL) {
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KFREE(isn);
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return ENOMEM;
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}
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bcopy((char *)&ips.ips_fr, (char *)fr, sizeof(*fr));
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out = fr->fr_flags & FR_OUTQUE ? 1 : 0;
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isn->is_rule = fr;
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ips.ips_is.is_rule = fr;
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if (*fr->fr_ifname) {
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fr->fr_ifa = GETUNIT(fr->fr_ifname, fr->fr_v);
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if (fr->fr_ifa == NULL)
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fr->fr_ifa = (void *)-1;
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#ifdef _KERNEL
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else {
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strncpy(isn->is_ifname[out],
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IFNAME(fr->fr_ifa), IFNAMSIZ);
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isn->is_ifp[out] = fr->fr_ifa;
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}
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#endif
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} else
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fr->fr_ifa = NULL;
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/*
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* send a copy back to userland of what we ended up
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* to allow for verification.
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*/
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error = IWCOPY((caddr_t)&ips, ipsp, sizeof(ips));
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if (error) {
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KFREE(isn);
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KFREE(fr);
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return EFAULT;
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}
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} else {
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for (is = ips_list; is; is = is->is_next)
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if (is->is_rule == fr)
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break;
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if (!is) {
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KFREE(isn);
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return ESRCH;
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}
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}
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}
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fr_stinsert(isn);
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return 0;
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}
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void fr_stinsert(is)
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register ipstate_t *is;
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{
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register u_int hv = is->is_hv;
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MUTEX_INIT(&is->is_lock, "ipf state entry", NULL);
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is->is_ifname[0][sizeof(is->is_ifname[0]) - 1] = '\0';
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if (is->is_ifname[0][0] != '\0') {
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is->is_ifp[0] = GETUNIT(is->is_ifname[0], is->is_v);
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}
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is->is_ifname[1][sizeof(is->is_ifname[0]) - 1] = '\0';
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if (is->is_ifname[1][0] != '\0') {
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is->is_ifp[1] = GETUNIT(is->is_ifname[1], is->is_v);
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}
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/*
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* add into list table.
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*/
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if (ips_list)
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ips_list->is_pnext = &is->is_next;
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is->is_pnext = &ips_list;
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is->is_next = ips_list;
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ips_list = is;
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if (ips_table[hv])
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ips_table[hv]->is_phnext = &is->is_hnext;
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else
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ips_stats.iss_inuse++;
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is->is_phnext = ips_table + hv;
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is->is_hnext = ips_table[hv];
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ips_table[hv] = is;
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ips_num++;
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}
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/*
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* Create a new ipstate structure and hang it off the hash table.
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*/
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ipstate_t *fr_addstate(ip, fin, flags)
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ip_t *ip;
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fr_info_t *fin;
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u_int flags;
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{
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register tcphdr_t *tcp = NULL;
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register ipstate_t *is;
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register u_int hv;
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ipstate_t ips;
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u_int pass;
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int out;
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if (fr_state_lock || (fin->fin_off & IP_OFFMASK) ||
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(fin->fin_fi.fi_fl & FI_SHORT))
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return NULL;
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if (ips_num == fr_statemax) {
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ips_stats.iss_max++;
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fr_state_doflush = 1;
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return NULL;
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}
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out = fin->fin_out;
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is = &ips;
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bzero((char *)is, sizeof(*is));
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ips.is_age = 1;
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ips.is_state[0] = 0;
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ips.is_state[1] = 0;
|
|
/*
|
|
* Copy and calculate...
|
|
*/
|
|
hv = (is->is_p = fin->fin_fi.fi_p);
|
|
is->is_src = fin->fin_fi.fi_src;
|
|
hv += is->is_saddr;
|
|
is->is_dst = fin->fin_fi.fi_dst;
|
|
hv += is->is_daddr;
|
|
#ifdef USE_INET6
|
|
if (fin->fin_v == 6) {
|
|
if (is->is_p == IPPROTO_ICMPV6) {
|
|
if (IN6_IS_ADDR_MULTICAST(&is->is_dst.in6))
|
|
flags |= FI_W_DADDR;
|
|
if (out)
|
|
hv -= is->is_daddr;
|
|
else
|
|
hv -= is->is_saddr;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
switch (is->is_p)
|
|
{
|
|
#ifdef USE_INET6
|
|
case IPPROTO_ICMPV6 :
|
|
#endif
|
|
case IPPROTO_ICMP :
|
|
{
|
|
struct icmp *ic = (struct icmp *)fin->fin_dp;
|
|
|
|
#ifdef USE_INET6
|
|
if ((is->is_p == IPPROTO_ICMPV6) &&
|
|
((ic->icmp_type & ICMP6_INFOMSG_MASK) == 0))
|
|
return NULL;
|
|
#endif
|
|
switch (ic->icmp_type)
|
|
{
|
|
#ifdef USE_INET6
|
|
case ICMP6_ECHO_REQUEST :
|
|
is->is_icmp.ics_type = ICMP6_ECHO_REPLY;
|
|
hv += (is->is_icmp.ics_id = ic->icmp_id);
|
|
hv += (is->is_icmp.ics_seq = ic->icmp_seq);
|
|
break;
|
|
case ICMP6_MEMBERSHIP_QUERY :
|
|
case ND_ROUTER_SOLICIT :
|
|
case ND_NEIGHBOR_SOLICIT :
|
|
is->is_icmp.ics_type = ic->icmp_type + 1;
|
|
break;
|
|
#endif
|
|
case ICMP_ECHO :
|
|
case ICMP_TSTAMP :
|
|
case ICMP_IREQ :
|
|
case ICMP_MASKREQ :
|
|
is->is_icmp.ics_type = ic->icmp_type;
|
|
hv += (is->is_icmp.ics_id = ic->icmp_id);
|
|
hv += (is->is_icmp.ics_seq = ic->icmp_seq);
|
|
break;
|
|
default :
|
|
return NULL;
|
|
}
|
|
ATOMIC_INCL(ips_stats.iss_icmp);
|
|
is->is_age = fr_icmptimeout;
|
|
break;
|
|
}
|
|
case IPPROTO_TCP :
|
|
{
|
|
tcp = (tcphdr_t *)fin->fin_dp;
|
|
|
|
if (tcp->th_flags & TH_RST)
|
|
return NULL;
|
|
/*
|
|
* The endian of the ports doesn't matter, but the ack and
|
|
* sequence numbers do as we do mathematics on them later.
|
|
*/
|
|
is->is_dport = tcp->th_dport;
|
|
is->is_sport = tcp->th_sport;
|
|
if ((flags & (FI_W_DPORT|FI_W_SPORT)) == 0) {
|
|
hv += tcp->th_dport;
|
|
hv += tcp->th_sport;
|
|
}
|
|
is->is_send = ntohl(tcp->th_seq) + ip->ip_len -
|
|
fin->fin_hlen - (tcp->th_off << 2) +
|
|
((tcp->th_flags & TH_SYN) ? 1 : 0) +
|
|
((tcp->th_flags & TH_FIN) ? 1 : 0);
|
|
is->is_maxsend = is->is_send;
|
|
is->is_dend = 0;
|
|
is->is_maxdwin = 1;
|
|
is->is_maxswin = ntohs(tcp->th_win);
|
|
if (is->is_maxswin == 0)
|
|
is->is_maxswin = 1;
|
|
/*
|
|
* If we're creating state for a starting connection, start the
|
|
* timer on it as we'll never see an error if it fails to
|
|
* connect.
|
|
*/
|
|
ATOMIC_INCL(ips_stats.iss_tcp);
|
|
break;
|
|
}
|
|
case IPPROTO_UDP :
|
|
{
|
|
tcp = (tcphdr_t *)fin->fin_dp;
|
|
|
|
is->is_dport = tcp->th_dport;
|
|
is->is_sport = tcp->th_sport;
|
|
if ((flags & (FI_W_DPORT|FI_W_SPORT)) == 0) {
|
|
hv += tcp->th_dport;
|
|
hv += tcp->th_sport;
|
|
}
|
|
ATOMIC_INCL(ips_stats.iss_udp);
|
|
is->is_age = fr_udptimeout;
|
|
break;
|
|
}
|
|
default :
|
|
return NULL;
|
|
}
|
|
|
|
KMALLOC(is, ipstate_t *);
|
|
if (is == NULL) {
|
|
ATOMIC_INCL(ips_stats.iss_nomem);
|
|
return NULL;
|
|
}
|
|
bcopy((char *)&ips, (char *)is, sizeof(*is));
|
|
hv %= fr_statesize;
|
|
is->is_hv = hv;
|
|
is->is_rule = fin->fin_fr;
|
|
if (is->is_rule != NULL) {
|
|
ATOMIC_INC32(is->is_rule->fr_ref);
|
|
pass = is->is_rule->fr_flags;
|
|
} else
|
|
pass = fr_flags;
|
|
WRITE_ENTER(&ipf_state);
|
|
|
|
is->is_pass = pass;
|
|
is->is_pkts = 1;
|
|
is->is_bytes = fin->fin_dlen + fin->fin_hlen;
|
|
/*
|
|
* We want to check everything that is a property of this packet,
|
|
* but we don't (automatically) care about it's fragment status as
|
|
* this may change.
|
|
*/
|
|
is->is_v = fin->fin_fi.fi_v;
|
|
is->is_opt = fin->fin_fi.fi_optmsk;
|
|
is->is_optmsk = 0xffffffff;
|
|
is->is_sec = fin->fin_fi.fi_secmsk;
|
|
is->is_secmsk = 0xffff;
|
|
is->is_auth = fin->fin_fi.fi_auth;
|
|
is->is_authmsk = 0xffff;
|
|
is->is_flags = fin->fin_fi.fi_fl & FI_CMP;
|
|
is->is_flags |= FI_CMP << 4;
|
|
is->is_flags |= flags & (FI_WILDP|FI_WILDA);
|
|
is->is_ifp[1 - out] = NULL;
|
|
is->is_ifp[out] = fin->fin_ifp;
|
|
#ifdef _KERNEL
|
|
strncpy(is->is_ifname[out], IFNAME(fin->fin_ifp), IFNAMSIZ);
|
|
#endif
|
|
is->is_ifname[1 - out][0] = '\0';
|
|
if (pass & FR_LOGFIRST)
|
|
is->is_pass &= ~(FR_LOGFIRST|FR_LOG);
|
|
fr_stinsert(is);
|
|
if (is->is_p == IPPROTO_TCP) {
|
|
MUTEX_ENTER(&is->is_lock);
|
|
fr_tcp_age(&is->is_age, is->is_state, fin,
|
|
0); /* 0 = packet from the source */
|
|
MUTEX_EXIT(&is->is_lock);
|
|
}
|
|
#ifdef IPFILTER_LOG
|
|
ipstate_log(is, ISL_NEW);
|
|
#endif
|
|
RWLOCK_EXIT(&ipf_state);
|
|
fin->fin_rev = IP6NEQ(is->is_dst, fin->fin_fi.fi_dst);
|
|
if (fin->fin_fi.fi_fl & FI_FRAG)
|
|
ipfr_newfrag(ip, fin, pass ^ FR_KEEPSTATE);
|
|
return is;
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* check to see if a packet with TCP headers fits within the TCP window.
|
|
* change timeout depending on whether new packet is a SYN-ACK returning for a
|
|
* SYN or a RST or FIN which indicate time to close up shop.
|
|
*/
|
|
int fr_tcpstate(is, fin, ip, tcp)
|
|
ipstate_t *is;
|
|
fr_info_t *fin;
|
|
ip_t *ip;
|
|
tcphdr_t *tcp;
|
|
{
|
|
tcp_seq seq, ack, end;
|
|
int ackskew;
|
|
tcpdata_t *fdata, *tdata;
|
|
u_short win, maxwin;
|
|
int ret = 0;
|
|
int source;
|
|
|
|
/*
|
|
* Find difference between last checked packet and this packet.
|
|
*/
|
|
source = IP6EQ(fin->fin_fi.fi_src, is->is_src);
|
|
fdata = &is->is_tcp.ts_data[!source];
|
|
tdata = &is->is_tcp.ts_data[source];
|
|
seq = ntohl(tcp->th_seq);
|
|
ack = ntohl(tcp->th_ack);
|
|
win = ntohs(tcp->th_win);
|
|
end = seq + fin->fin_dlen - (tcp->th_off << 2) +
|
|
((tcp->th_flags & TH_SYN) ? 1 : 0) +
|
|
((tcp->th_flags & TH_FIN) ? 1 : 0);
|
|
|
|
if (fdata->td_end == 0) {
|
|
/*
|
|
* Must be a (outgoing) SYN-ACK in reply to a SYN.
|
|
*/
|
|
fdata->td_end = end;
|
|
fdata->td_maxwin = 1;
|
|
fdata->td_maxend = end + 1;
|
|
}
|
|
|
|
if (!(tcp->th_flags & TH_ACK)) { /* Pretend an ack was sent */
|
|
ack = tdata->td_end;
|
|
} else if (((tcp->th_flags & (TH_ACK|TH_RST)) == (TH_ACK|TH_RST)) &&
|
|
(ack == 0)) {
|
|
/* gross hack to get around certain broken tcp stacks */
|
|
ack = tdata->td_end;
|
|
}
|
|
|
|
if (seq == end)
|
|
seq = end = fdata->td_end;
|
|
|
|
maxwin = tdata->td_maxwin;
|
|
ackskew = tdata->td_end - ack;
|
|
|
|
#define SEQ_GE(a,b) ((int)((a) - (b)) >= 0)
|
|
#define SEQ_GT(a,b) ((int)((a) - (b)) > 0)
|
|
if ((SEQ_GE(fdata->td_maxend, end)) &&
|
|
(SEQ_GE(seq, fdata->td_end - maxwin)) &&
|
|
/* XXX what about big packets */
|
|
#define MAXACKWINDOW 66000
|
|
(ackskew >= -MAXACKWINDOW) &&
|
|
(ackskew <= MAXACKWINDOW)) {
|
|
/* if ackskew < 0 then this should be due to fragented
|
|
* packets. There is no way to know the length of the
|
|
* total packet in advance.
|
|
* We do know the total length from the fragment cache though.
|
|
* Note however that there might be more sessions with
|
|
* exactly the same source and destination paramters in the
|
|
* state cache (and source and destination is the only stuff
|
|
* that is saved in the fragment cache). Note further that
|
|
* some TCP connections in the state cache are hashed with
|
|
* sport and dport as well which makes it not worthwhile to
|
|
* look for them.
|
|
* Thus, when ackskew is negative but still seems to belong
|
|
* to this session, we bump up the destinations end value.
|
|
*/
|
|
if (ackskew < 0)
|
|
tdata->td_end = ack;
|
|
|
|
/* update max window seen */
|
|
if (fdata->td_maxwin < win)
|
|
fdata->td_maxwin = win;
|
|
if (SEQ_GT(end, fdata->td_end))
|
|
fdata->td_end = end;
|
|
if (SEQ_GE(ack + win, tdata->td_maxend)) {
|
|
tdata->td_maxend = ack + win;
|
|
if (win == 0)
|
|
tdata->td_maxend++;
|
|
}
|
|
|
|
ATOMIC_INCL(ips_stats.iss_hits);
|
|
is->is_pkts++;
|
|
is->is_bytes += fin->fin_dlen + fin->fin_hlen;
|
|
/*
|
|
* Nearing end of connection, start timeout.
|
|
*/
|
|
MUTEX_ENTER(&is->is_lock);
|
|
/* source ? 0 : 1 -> !source */
|
|
fr_tcp_age(&is->is_age, is->is_state, fin, !source);
|
|
MUTEX_EXIT(&is->is_lock);
|
|
ret = 1;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
|
|
static int fr_matchsrcdst(is, src, dst, fin, tcp)
|
|
ipstate_t *is;
|
|
union i6addr src, dst;
|
|
fr_info_t *fin;
|
|
tcphdr_t *tcp;
|
|
{
|
|
int ret = 0, rev, out, flags;
|
|
u_short sp, dp;
|
|
void *ifp;
|
|
|
|
rev = fin->fin_rev = IP6NEQ(is->is_dst, dst);
|
|
ifp = fin->fin_ifp;
|
|
out = fin->fin_out;
|
|
|
|
if (tcp != NULL) {
|
|
flags = is->is_flags;
|
|
sp = tcp->th_sport;
|
|
dp = tcp->th_dport;
|
|
} else {
|
|
flags = is->is_flags & FI_WILDA;
|
|
sp = 0;
|
|
dp = 0;
|
|
}
|
|
|
|
if (rev == 0) {
|
|
if (!out) {
|
|
if (is->is_ifpin == NULL || is->is_ifpin == ifp)
|
|
ret = 1;
|
|
} else {
|
|
if (is->is_ifpout == NULL || is->is_ifpout == ifp)
|
|
ret = 1;
|
|
}
|
|
} else {
|
|
if (out) {
|
|
if (is->is_ifpin == NULL || is->is_ifpin == ifp)
|
|
ret = 1;
|
|
} else {
|
|
if (is->is_ifpout == NULL || is->is_ifpout == ifp)
|
|
ret = 1;
|
|
}
|
|
}
|
|
if (ret == 0)
|
|
return 0;
|
|
ret = 0;
|
|
|
|
if (rev == 0) {
|
|
if (
|
|
(IP6EQ(is->is_dst, dst) || (flags & FI_W_DADDR)) &&
|
|
(IP6EQ(is->is_src, src) || (flags & FI_W_SADDR)) &&
|
|
(!tcp || ((sp == is->is_sport || flags & FI_W_SPORT) &&
|
|
(dp == is->is_dport || flags & FI_W_DPORT)))) {
|
|
ret = 1;
|
|
}
|
|
} else {
|
|
if (
|
|
(IP6EQ(is->is_dst, src) || (flags & FI_W_DADDR)) &&
|
|
(IP6EQ(is->is_src, dst) || (flags & FI_W_SADDR)) &&
|
|
(!tcp || ((sp == is->is_dport || flags & FI_W_DPORT) &&
|
|
(dp == is->is_sport || flags & FI_W_SPORT)))) {
|
|
ret = 1;
|
|
}
|
|
}
|
|
if (ret == 0)
|
|
return 0;
|
|
|
|
/*
|
|
* Whether or not this should be here, is questionable, but the aim
|
|
* is to get this out of the main line.
|
|
*/
|
|
if (tcp == NULL)
|
|
flags = is->is_flags & (FI_CMP|(FI_CMP<<4));
|
|
|
|
if (((fin->fin_fi.fi_fl & (flags >> 4)) != (flags & FI_CMP)) ||
|
|
((fin->fin_fi.fi_optmsk & is->is_optmsk) != is->is_opt) ||
|
|
((fin->fin_fi.fi_secmsk & is->is_secmsk) != is->is_sec) ||
|
|
((fin->fin_fi.fi_auth & is->is_authmsk) != is->is_auth))
|
|
return 0;
|
|
|
|
if ((flags & (FI_W_SPORT|FI_W_DPORT))) {
|
|
if ((flags & FI_W_SPORT) != 0) {
|
|
if (rev == 0) {
|
|
is->is_sport = sp;
|
|
is->is_send = htonl(tcp->th_seq);
|
|
} else {
|
|
is->is_sport = dp;
|
|
is->is_send = htonl(tcp->th_ack);
|
|
}
|
|
is->is_maxsend = is->is_send + 1;
|
|
} else if ((flags & FI_W_DPORT) != 0) {
|
|
if (rev == 0) {
|
|
is->is_dport = dp;
|
|
is->is_dend = htonl(tcp->th_ack);
|
|
} else {
|
|
is->is_dport = sp;
|
|
is->is_dend = htonl(tcp->th_seq);
|
|
}
|
|
is->is_maxdend = is->is_dend + 1;
|
|
}
|
|
is->is_flags &= ~(FI_W_SPORT|FI_W_DPORT);
|
|
}
|
|
|
|
ret = -1;
|
|
|
|
if (!rev) {
|
|
if (out) {
|
|
if (!is->is_ifpout)
|
|
ret = 1;
|
|
} else {
|
|
if (!is->is_ifpin)
|
|
ret = 0;
|
|
}
|
|
} else {
|
|
if (out) {
|
|
if (!is->is_ifpin)
|
|
ret = 0;
|
|
} else {
|
|
if (!is->is_ifpout)
|
|
ret = 1;
|
|
}
|
|
}
|
|
|
|
if (ret >= 0) {
|
|
is->is_ifp[ret] = ifp;
|
|
#ifdef _KERNEL
|
|
strncpy(is->is_ifname[out], IFNAME(fin->fin_ifp),
|
|
sizeof(is->is_ifname[1]));
|
|
#endif
|
|
}
|
|
#ifdef _KERNEL
|
|
if (ret >= 0) {
|
|
strncpy(is->is_ifname[out], IFNAME(fin->fin_ifp),
|
|
sizeof(is->is_ifname[1]));
|
|
}
|
|
#endif
|
|
return 1;
|
|
}
|
|
|
|
static int fr_matchicmpqueryreply(v, is, icmp)
|
|
int v;
|
|
ipstate_t *is;
|
|
icmphdr_t *icmp;
|
|
{
|
|
if (v == 4) {
|
|
/*
|
|
* If we matched its type on the way in, then when going out
|
|
* it will still be the same type.
|
|
*/
|
|
if (((icmp->icmp_type == is->is_type) ||
|
|
(icmpreplytype4[is->is_type] == icmp->icmp_type)) &&
|
|
(icmp->icmp_id == is->is_icmp.ics_id) &&
|
|
(icmp->icmp_seq == is->is_icmp.ics_seq)) {
|
|
return 1;
|
|
};
|
|
}
|
|
#ifdef USE_INET6
|
|
else if (is->is_v == 6) {
|
|
if ((is->is_type == ICMP6_ECHO_REPLY) &&
|
|
(icmp->icmp_type == ICMP6_ECHO_REQUEST) &&
|
|
(icmp->icmp_id == is->is_icmp.ics_id) &&
|
|
(icmp->icmp_seq == is->is_icmp.ics_seq)) {
|
|
return 1;
|
|
};
|
|
}
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
static frentry_t *fr_checkicmpmatchingstate(ip, fin)
|
|
ip_t *ip;
|
|
fr_info_t *fin;
|
|
{
|
|
register ipstate_t *is, **isp;
|
|
register u_short sport, dport;
|
|
register u_char pr;
|
|
union i6addr dst, src;
|
|
struct icmp *ic;
|
|
u_short savelen;
|
|
icmphdr_t *icmp;
|
|
fr_info_t ofin;
|
|
int type, len;
|
|
tcphdr_t *tcp;
|
|
frentry_t *fr;
|
|
ip_t *oip;
|
|
u_int hv;
|
|
|
|
/*
|
|
* Does it at least have the return (basic) IP header ?
|
|
* Only a basic IP header (no options) should be with
|
|
* an ICMP error header.
|
|
*/
|
|
if (((ip->ip_v != 4) && (ip->ip_hl != 5)) ||
|
|
(fin->fin_plen < ICMPERR_MINPKTLEN))
|
|
return NULL;
|
|
ic = (struct icmp *)fin->fin_dp;
|
|
type = ic->icmp_type;
|
|
/*
|
|
* If it's not an error type, then return
|
|
*/
|
|
if ((type != ICMP_UNREACH) && (type != ICMP_SOURCEQUENCH) &&
|
|
(type != ICMP_REDIRECT) && (type != ICMP_TIMXCEED) &&
|
|
(type != ICMP_PARAMPROB))
|
|
return NULL;
|
|
|
|
oip = (ip_t *)((char *)ic + ICMPERR_ICMPHLEN);
|
|
if (fin->fin_plen < ICMPERR_MAXPKTLEN + ((oip->ip_hl - 5) << 2))
|
|
return NULL;
|
|
|
|
/*
|
|
* Sanity checks.
|
|
*/
|
|
len = fin->fin_dlen - ICMPERR_ICMPHLEN;
|
|
if ((len <= 0) || ((oip->ip_hl << 2) > len))
|
|
return NULL;
|
|
|
|
/*
|
|
* Is the buffer big enough for all of it ? It's the size of the IP
|
|
* header claimed in the encapsulated part which is of concern. It
|
|
* may be too big to be in this buffer but not so big that it's
|
|
* outside the ICMP packet, leading to TCP deref's causing problems.
|
|
* This is possible because we don't know how big oip_hl is when we
|
|
* do the pullup early in fr_check() and thus can't gaurantee it is
|
|
* all here now.
|
|
*/
|
|
#ifdef _KERNEL
|
|
{
|
|
mb_t *m;
|
|
|
|
# if SOLARIS
|
|
m = fin->fin_qfm;
|
|
if ((char *)oip + len > (char *)m->b_wptr)
|
|
return NULL;
|
|
# else
|
|
m = *(mb_t **)fin->fin_mp;
|
|
if ((char *)oip + len > (char *)ip + m->m_len)
|
|
return NULL;
|
|
# endif
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* in the IPv4 case we must zero the i6addr union otherwise
|
|
* the IP6EQ and IP6NEQ macros produce the wrong results because
|
|
* of the 'junk' in the unused part of the union
|
|
*/
|
|
bzero(&src, sizeof(src));
|
|
bzero(&dst, sizeof(dst));
|
|
|
|
if (oip->ip_p == IPPROTO_ICMP) {
|
|
icmp = (icmphdr_t *)((char *)oip + (oip->ip_hl << 2));
|
|
|
|
/*
|
|
* a ICMP error can only be generated as a result of an
|
|
* ICMP query, not as the response on an ICMP error
|
|
*
|
|
* XXX theoretically ICMP_ECHOREP and the other reply's are
|
|
* ICMP query's as well, but adding them here seems strange XXX
|
|
*/
|
|
if ((icmp->icmp_type != ICMP_ECHO) &&
|
|
(icmp->icmp_type != ICMP_TSTAMP) &&
|
|
(icmp->icmp_type != ICMP_IREQ) &&
|
|
(icmp->icmp_type != ICMP_MASKREQ))
|
|
return NULL;
|
|
|
|
/*
|
|
* perform a lookup of the ICMP packet in the state table
|
|
*/
|
|
hv = (pr = oip->ip_p);
|
|
src.in4 = oip->ip_src;
|
|
hv += src.in4.s_addr;
|
|
dst.in4 = oip->ip_dst;
|
|
hv += dst.in4.s_addr;
|
|
hv += icmp->icmp_id;
|
|
hv += icmp->icmp_seq;
|
|
hv %= fr_statesize;
|
|
|
|
savelen = oip->ip_len;
|
|
oip->ip_len = len;
|
|
ofin.fin_v = 4;
|
|
fr_makefrip(oip->ip_hl << 2, oip, &ofin);
|
|
oip->ip_len = savelen;
|
|
ofin.fin_ifp = fin->fin_ifp;
|
|
ofin.fin_out = !fin->fin_out;
|
|
ofin.fin_mp = NULL; /* if dereferenced, panic XXX */
|
|
|
|
READ_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_hnext)
|
|
if ((is->is_p == pr) && (is->is_v == 4) &&
|
|
fr_matchsrcdst(is, src, dst, &ofin, NULL) &&
|
|
fr_matchicmpqueryreply(is->is_v, is, icmp)) {
|
|
ips_stats.iss_hits++;
|
|
is->is_pkts++;
|
|
is->is_bytes += ip->ip_len;
|
|
fr = is->is_rule;
|
|
RWLOCK_EXIT(&ipf_state);
|
|
return fr;
|
|
}
|
|
RWLOCK_EXIT(&ipf_state);
|
|
return NULL;
|
|
};
|
|
|
|
if ((oip->ip_p != IPPROTO_TCP) && (oip->ip_p != IPPROTO_UDP))
|
|
return NULL;
|
|
|
|
tcp = (tcphdr_t *)((char *)oip + (oip->ip_hl << 2));
|
|
dport = tcp->th_dport;
|
|
sport = tcp->th_sport;
|
|
|
|
hv = (pr = oip->ip_p);
|
|
src.in4 = oip->ip_src;
|
|
hv += src.in4.s_addr;
|
|
dst.in4 = oip->ip_dst;
|
|
hv += dst.in4.s_addr;
|
|
hv += dport;
|
|
hv += sport;
|
|
hv %= fr_statesize;
|
|
/*
|
|
* we make an fin entry to be able to feed it to
|
|
* matchsrcdst note that not all fields are encessary
|
|
* but this is the cleanest way. Note further we fill
|
|
* in fin_mp such that if someone uses it we'll get
|
|
* a kernel panic. fr_matchsrcdst does not use this.
|
|
*
|
|
* watch out here, as ip is in host order and oip in network
|
|
* order. Any change we make must be undone afterwards.
|
|
*/
|
|
savelen = oip->ip_len;
|
|
oip->ip_len = len;
|
|
ofin.fin_v = 4;
|
|
fr_makefrip(oip->ip_hl << 2, oip, &ofin);
|
|
oip->ip_len = savelen;
|
|
ofin.fin_ifp = fin->fin_ifp;
|
|
ofin.fin_out = !fin->fin_out;
|
|
ofin.fin_mp = NULL; /* if dereferenced, panic XXX */
|
|
READ_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_hnext) {
|
|
/*
|
|
* Only allow this icmp though if the
|
|
* encapsulated packet was allowed through the
|
|
* other way around. Note that the minimal amount
|
|
* of info present does not allow for checking against
|
|
* tcp internals such as seq and ack numbers.
|
|
*/
|
|
if ((is->is_p == pr) && (is->is_v == 4) &&
|
|
fr_matchsrcdst(is, src, dst, &ofin, tcp)) {
|
|
fr = is->is_rule;
|
|
ips_stats.iss_hits++;
|
|
/*
|
|
* we must swap src and dst here because the icmp
|
|
* comes the other way around
|
|
*/
|
|
is->is_pkts++;
|
|
is->is_bytes += fin->fin_plen;
|
|
/*
|
|
* we deliberately do not touch the timeouts
|
|
* for the accompanying state table entry.
|
|
* It remains to be seen if that is correct. XXX
|
|
*/
|
|
RWLOCK_EXIT(&ipf_state);
|
|
return fr;
|
|
}
|
|
}
|
|
RWLOCK_EXIT(&ipf_state);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Check if a packet has a registered state.
|
|
*/
|
|
frentry_t *fr_checkstate(ip, fin)
|
|
ip_t *ip;
|
|
fr_info_t *fin;
|
|
{
|
|
union i6addr dst, src;
|
|
register ipstate_t *is, **isp;
|
|
register u_char pr;
|
|
u_int hv, hvm, hlen, tryagain, pass, v;
|
|
struct icmp *ic;
|
|
frentry_t *fr;
|
|
tcphdr_t *tcp;
|
|
|
|
if (fr_state_lock || (fin->fin_off & IP_OFFMASK) ||
|
|
(fin->fin_fi.fi_fl & FI_SHORT))
|
|
return NULL;
|
|
|
|
is = NULL;
|
|
hlen = fin->fin_hlen;
|
|
tcp = (tcphdr_t *)((char *)ip + hlen);
|
|
ic = (struct icmp *)tcp;
|
|
hv = (pr = fin->fin_fi.fi_p);
|
|
src = fin->fin_fi.fi_src;
|
|
dst = fin->fin_fi.fi_dst;
|
|
hv += src.in4.s_addr;
|
|
hv += dst.in4.s_addr;
|
|
|
|
/*
|
|
* Search the hash table for matching packet header info.
|
|
*/
|
|
v = fin->fin_fi.fi_v;
|
|
switch (fin->fin_fi.fi_p)
|
|
{
|
|
#ifdef USE_INET6
|
|
case IPPROTO_ICMPV6 :
|
|
if (v == 6) {
|
|
if (fin->fin_out)
|
|
hv -= dst.in4.s_addr;
|
|
else
|
|
hv -= src.in4.s_addr;
|
|
if ((ic->icmp_type == ICMP6_ECHO_REQUEST) ||
|
|
(ic->icmp_type == ICMP6_ECHO_REPLY)) {
|
|
hv += ic->icmp_id;
|
|
hv += ic->icmp_seq;
|
|
}
|
|
}
|
|
#endif
|
|
case IPPROTO_ICMP :
|
|
if (v == 4) {
|
|
hv += ic->icmp_id;
|
|
hv += ic->icmp_seq;
|
|
}
|
|
hv %= fr_statesize;
|
|
READ_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_hnext) {
|
|
if ((is->is_p == pr) && (is->is_v == v) &&
|
|
fr_matchsrcdst(is, src, dst, fin, NULL) &&
|
|
fr_matchicmpqueryreply(v, is, ic)) {
|
|
is->is_age = fr_icmptimeout;
|
|
break;
|
|
}
|
|
}
|
|
if (is != NULL)
|
|
break;
|
|
RWLOCK_EXIT(&ipf_state);
|
|
/*
|
|
* No matching icmp state entry. Perhaps this is a
|
|
* response to another state entry.
|
|
*/
|
|
#ifdef USE_INET6
|
|
if (v == 6)
|
|
fr = fr_checkicmp6matchingstate((ip6_t *)ip, fin);
|
|
else
|
|
#endif
|
|
fr = fr_checkicmpmatchingstate(ip, fin);
|
|
if (fr)
|
|
return fr;
|
|
break;
|
|
case IPPROTO_TCP :
|
|
{
|
|
u_short dport = tcp->th_dport, sport = tcp->th_sport;
|
|
int i;
|
|
|
|
i = tcp->th_flags;
|
|
/*
|
|
* Just plain ignore RST flag set with either FIN or SYN.
|
|
*/
|
|
if ((i & TH_RST) &&
|
|
((i & (TH_FIN|TH_SYN|TH_RST)) != TH_RST))
|
|
break;
|
|
tryagain = 0;
|
|
retry_tcp:
|
|
hvm = hv % fr_statesize;
|
|
WRITE_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hvm]; (is = *isp);
|
|
isp = &is->is_hnext)
|
|
|
|
|
|
if ((is->is_p == pr) && (is->is_v == v) &&
|
|
fr_matchsrcdst(is, src, dst, fin, tcp)) {
|
|
if (fr_tcpstate(is, fin, ip, tcp))
|
|
break;
|
|
is = NULL;
|
|
break;
|
|
}
|
|
if (is != NULL)
|
|
break;
|
|
RWLOCK_EXIT(&ipf_state);
|
|
hv += dport;
|
|
hv += sport;
|
|
if (tryagain == 0) {
|
|
tryagain = 1;
|
|
goto retry_tcp;
|
|
}
|
|
break;
|
|
}
|
|
case IPPROTO_UDP :
|
|
{
|
|
u_short dport = tcp->th_dport, sport = tcp->th_sport;
|
|
|
|
tryagain = 0;
|
|
retry_udp:
|
|
hvm = hv % fr_statesize;
|
|
/*
|
|
* Nothing else to match on but ports. and IP#'s
|
|
*/
|
|
READ_ENTER(&ipf_state);
|
|
for (is = ips_table[hvm]; is; is = is->is_hnext)
|
|
if ((is->is_p == pr) && (is->is_v == v) &&
|
|
fr_matchsrcdst(is, src, dst, fin, tcp)) {
|
|
is->is_age = fr_udptimeout;
|
|
break;
|
|
}
|
|
if (is != NULL)
|
|
break;
|
|
RWLOCK_EXIT(&ipf_state);
|
|
hv += dport;
|
|
hv += sport;
|
|
if (tryagain == 0) {
|
|
tryagain = 1;
|
|
goto retry_udp;
|
|
}
|
|
break;
|
|
}
|
|
default :
|
|
break;
|
|
}
|
|
if (is == NULL) {
|
|
ATOMIC_INCL(ips_stats.iss_miss);
|
|
return NULL;
|
|
}
|
|
MUTEX_ENTER(&is->is_lock);
|
|
is->is_bytes += fin->fin_plen;
|
|
ips_stats.iss_hits++;
|
|
is->is_pkts++;
|
|
MUTEX_EXIT(&is->is_lock);
|
|
fr = is->is_rule;
|
|
fin->fin_fr = fr;
|
|
pass = is->is_pass;
|
|
#ifndef _KERNEL
|
|
if (tcp->th_flags & TCP_CLOSE)
|
|
fr_delstate(is);
|
|
#endif
|
|
RWLOCK_EXIT(&ipf_state);
|
|
if (fin->fin_fi.fi_fl & FI_FRAG)
|
|
ipfr_newfrag(ip, fin, pass ^ FR_KEEPSTATE);
|
|
return fr;
|
|
}
|
|
|
|
|
|
void ip_statesync(ifp)
|
|
void *ifp;
|
|
{
|
|
register ipstate_t *is;
|
|
|
|
WRITE_ENTER(&ipf_state);
|
|
for (is = ips_list; is; is = is->is_next) {
|
|
if (is->is_ifpin == ifp) {
|
|
is->is_ifpin = GETUNIT(is->is_ifname[0], is->is_v);
|
|
if (!is->is_ifpin)
|
|
is->is_ifpin = (void *)-1;
|
|
}
|
|
if (is->is_ifpout == ifp) {
|
|
is->is_ifpout = GETUNIT(is->is_ifname[1], is->is_v);
|
|
if (!is->is_ifpout)
|
|
is->is_ifpout = (void *)-1;
|
|
}
|
|
}
|
|
RWLOCK_EXIT(&ipf_state);
|
|
}
|
|
|
|
|
|
static void fr_delstate(is)
|
|
ipstate_t *is;
|
|
{
|
|
frentry_t *fr;
|
|
|
|
if (is->is_next)
|
|
is->is_next->is_pnext = is->is_pnext;
|
|
*is->is_pnext = is->is_next;
|
|
if (is->is_hnext)
|
|
is->is_hnext->is_phnext = is->is_phnext;
|
|
*is->is_phnext = is->is_hnext;
|
|
if (ips_table[is->is_hv] == NULL)
|
|
ips_stats.iss_inuse--;
|
|
|
|
fr = is->is_rule;
|
|
if (fr != NULL) {
|
|
ATOMIC_DEC32(fr->fr_ref);
|
|
if (fr->fr_ref == 0)
|
|
KFREE(fr);
|
|
}
|
|
#ifdef _KERNEL
|
|
MUTEX_DESTROY(&is->is_lock);
|
|
#endif
|
|
KFREE(is);
|
|
ips_num--;
|
|
}
|
|
|
|
|
|
/*
|
|
* Free memory in use by all state info. kept.
|
|
*/
|
|
void fr_stateunload()
|
|
{
|
|
register ipstate_t *is;
|
|
|
|
WRITE_ENTER(&ipf_state);
|
|
while ((is = ips_list))
|
|
fr_delstate(is);
|
|
ips_stats.iss_inuse = 0;
|
|
ips_num = 0;
|
|
RWLOCK_EXIT(&ipf_state);
|
|
KFREES(ips_table, fr_statesize * sizeof(ipstate_t *));
|
|
ips_table = NULL;
|
|
}
|
|
|
|
|
|
/*
|
|
* Slowly expire held state for thingslike UDP and ICMP. Timeouts are set
|
|
* in expectation of this being called twice per second.
|
|
*/
|
|
void fr_timeoutstate()
|
|
{
|
|
register ipstate_t *is, **isp;
|
|
#if defined(_KERNEL) && !SOLARIS
|
|
int s;
|
|
#endif
|
|
|
|
SPL_NET(s);
|
|
WRITE_ENTER(&ipf_state);
|
|
for (isp = &ips_list; (is = *isp); )
|
|
if (is->is_age && !--is->is_age) {
|
|
if (is->is_p == IPPROTO_TCP)
|
|
ips_stats.iss_fin++;
|
|
else
|
|
ips_stats.iss_expire++;
|
|
#ifdef IPFILTER_LOG
|
|
ipstate_log(is, ISL_EXPIRE);
|
|
#endif
|
|
fr_delstate(is);
|
|
} else
|
|
isp = &is->is_next;
|
|
RWLOCK_EXIT(&ipf_state);
|
|
SPL_X(s);
|
|
if (fr_state_doflush) {
|
|
(void) fr_state_flush(1);
|
|
fr_state_doflush = 0;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Original idea freom Pradeep Krishnan for use primarily with NAT code.
|
|
* (pkrishna@netcom.com)
|
|
*
|
|
* Rewritten by Arjan de Vet <Arjan.deVet@adv.iae.nl>, 2000-07-29:
|
|
*
|
|
* - (try to) base state transitions on real evidence only,
|
|
* i.e. packets that are sent and have been received by ipfilter;
|
|
* diagram 18.12 of TCP/IP volume 1 by W. Richard Stevens was used.
|
|
*
|
|
* - deal with half-closed connections correctly;
|
|
*
|
|
* - store the state of the source in state[0] such that ipfstat
|
|
* displays the state as source/dest instead of dest/source; the calls
|
|
* to fr_tcp_age have been changed accordingly.
|
|
*
|
|
* Parameters:
|
|
*
|
|
* state[0] = state of source (host that initiated connection)
|
|
* state[1] = state of dest (host that accepted the connection)
|
|
*
|
|
* dir == 0 : a packet from source to dest
|
|
* dir == 1 : a packet from dest to source
|
|
*
|
|
*/
|
|
void fr_tcp_age(age, state, fin, dir)
|
|
u_long *age;
|
|
u_char *state;
|
|
fr_info_t *fin;
|
|
int dir;
|
|
{
|
|
tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
|
|
u_char flags = tcp->th_flags;
|
|
int dlen, ostate;
|
|
|
|
ostate = state[1 - dir];
|
|
|
|
dlen = fin->fin_plen - fin->fin_hlen - (tcp->th_off << 2);
|
|
|
|
if (flags & TH_RST) {
|
|
if (!(tcp->th_flags & TH_PUSH) && !dlen) {
|
|
*age = fr_tcpclosed;
|
|
state[dir] = TCPS_CLOSED;
|
|
} else {
|
|
*age = fr_tcpclosewait;
|
|
state[dir] = TCPS_CLOSE_WAIT;
|
|
}
|
|
return;
|
|
}
|
|
|
|
*age = fr_tcptimeout; /* default 4 mins */
|
|
|
|
switch(state[dir])
|
|
{
|
|
case TCPS_CLOSED: /* 0 */
|
|
if ((flags & TH_OPENING) == TH_OPENING) {
|
|
/*
|
|
* 'dir' received an S and sends SA in response,
|
|
* CLOSED -> SYN_RECEIVED
|
|
*/
|
|
state[dir] = TCPS_SYN_RECEIVED;
|
|
*age = fr_tcptimeout;
|
|
} else if ((flags & (TH_SYN|TH_ACK)) == TH_SYN) {
|
|
/* 'dir' sent S, CLOSED -> SYN_SENT */
|
|
state[dir] = TCPS_SYN_SENT;
|
|
*age = fr_tcptimeout;
|
|
}
|
|
/*
|
|
* The next piece of code makes it possible to get
|
|
* already established connections into the state table
|
|
* after a restart or reload of the filter rules; this
|
|
* does not work when a strict 'flags S keep state' is
|
|
* used for tcp connections of course
|
|
*/
|
|
if ((flags & (TH_FIN|TH_SYN|TH_RST|TH_ACK)) == TH_ACK) {
|
|
/* we saw an A, guess 'dir' is in ESTABLISHED mode */
|
|
state[dir] = TCPS_ESTABLISHED;
|
|
*age = fr_tcpidletimeout;
|
|
}
|
|
/*
|
|
* TODO: besides regular ACK packets we can have other
|
|
* packets as well; it is yet to be determined how we
|
|
* should initialize the states in those cases
|
|
*/
|
|
break;
|
|
|
|
case TCPS_LISTEN: /* 1 */
|
|
/* NOT USED */
|
|
break;
|
|
|
|
case TCPS_SYN_SENT: /* 2 */
|
|
if ((flags & (TH_SYN|TH_FIN|TH_ACK)) == TH_ACK) {
|
|
/*
|
|
* We see an A from 'dir' which is in SYN_SENT
|
|
* state: 'dir' sent an A in response to an SA
|
|
* which it received, SYN_SENT -> ESTABLISHED
|
|
*/
|
|
state[dir] = TCPS_ESTABLISHED;
|
|
*age = fr_tcpidletimeout;
|
|
} else if (flags & TH_FIN) {
|
|
/*
|
|
* We see an F from 'dir' which is in SYN_SENT
|
|
* state and wants to close its side of the
|
|
* connection; SYN_SENT -> FIN_WAIT_1
|
|
*/
|
|
state[dir] = TCPS_FIN_WAIT_1;
|
|
*age = fr_tcpidletimeout; /* or fr_tcptimeout? */
|
|
} else if ((flags & TH_OPENING) == TH_OPENING) {
|
|
/*
|
|
* We see an SA from 'dir' which is already in
|
|
* SYN_SENT state, this means we have a
|
|
* simultaneous open; SYN_SENT -> SYN_RECEIVED
|
|
*/
|
|
state[dir] = TCPS_SYN_RECEIVED;
|
|
*age = fr_tcptimeout;
|
|
}
|
|
break;
|
|
|
|
case TCPS_SYN_RECEIVED: /* 3 */
|
|
if ((flags & (TH_SYN|TH_FIN|TH_ACK)) == TH_ACK) {
|
|
/*
|
|
* We see an A from 'dir' which was in SYN_RECEIVED
|
|
* state so it must now be in established state,
|
|
* SYN_RECEIVED -> ESTABLISHED
|
|
*/
|
|
state[dir] = TCPS_ESTABLISHED;
|
|
*age = fr_tcpidletimeout;
|
|
} else if (flags & TH_FIN) {
|
|
/*
|
|
* We see an F from 'dir' which is in SYN_RECEIVED
|
|
* state and wants to close its side of the connection;
|
|
* SYN_RECEIVED -> FIN_WAIT_1
|
|
*/
|
|
state[dir] = TCPS_FIN_WAIT_1;
|
|
*age = fr_tcpidletimeout; /* or fr_tcptimeout? */
|
|
}
|
|
break;
|
|
|
|
case TCPS_ESTABLISHED: /* 4 */
|
|
if (flags & TH_FIN) {
|
|
/*
|
|
* 'dir' closed its side of the connection; this
|
|
* gives us a half-closed connection;
|
|
* ESTABLISHED -> FIN_WAIT_1
|
|
*/
|
|
state[dir] = TCPS_FIN_WAIT_1;
|
|
*age = fr_tcpidletimeout;
|
|
} else if (flags & TH_ACK) {
|
|
/* an ACK, should we exclude other flags here? */
|
|
if (ostate == TCPS_FIN_WAIT_1) {
|
|
/*
|
|
* We know the other side did an active close,
|
|
* so we are ACKing the recvd FIN packet (does
|
|
* the window matching code guarantee this?)
|
|
* and go into CLOSE_WAIT state; this gives us
|
|
* a half-closed connection
|
|
*/
|
|
state[dir] = TCPS_CLOSE_WAIT;
|
|
*age = fr_tcpidletimeout;
|
|
} else if (ostate < TCPS_CLOSE_WAIT)
|
|
/*
|
|
* Still a fully established connection,
|
|
* reset timeout
|
|
*/
|
|
*age = fr_tcpidletimeout;
|
|
}
|
|
break;
|
|
|
|
case TCPS_CLOSE_WAIT: /* 5 */
|
|
if (flags & TH_FIN) {
|
|
/*
|
|
* Application closed and 'dir' sent a FIN, we're now
|
|
* going into LAST_ACK state
|
|
*/
|
|
*age = fr_tcplastack;
|
|
state[dir] = TCPS_LAST_ACK;
|
|
} else {
|
|
/*
|
|
* We remain in CLOSE_WAIT because the other side has
|
|
* closed already and we did not close our side yet;
|
|
* reset timeout
|
|
*/
|
|
*age = fr_tcpidletimeout;
|
|
}
|
|
break;
|
|
|
|
case TCPS_FIN_WAIT_1: /* 6 */
|
|
if ((flags & TH_ACK) && ostate > TCPS_CLOSE_WAIT) {
|
|
/*
|
|
* If the other side is not active anymore it has sent
|
|
* us a FIN packet that we are ack'ing now with an ACK;
|
|
* this means both sides have now closed the connection
|
|
* and we go into TIME_WAIT
|
|
*/
|
|
/*
|
|
* XXX: how do we know we really are ACKing the FIN
|
|
* packet here? does the window code guarantee that?
|
|
*/
|
|
state[dir] = TCPS_TIME_WAIT;
|
|
*age = fr_tcptimeout;
|
|
} else
|
|
/*
|
|
* We closed our side of the connection already but the
|
|
* other side is still active (ESTABLISHED/CLOSE_WAIT);
|
|
* continue with this half-closed connection
|
|
*/
|
|
*age = fr_tcpidletimeout;
|
|
break;
|
|
|
|
case TCPS_CLOSING: /* 7 */
|
|
/* NOT USED */
|
|
break;
|
|
|
|
case TCPS_LAST_ACK: /* 8 */
|
|
if (flags & TH_ACK) {
|
|
if ((flags & TH_PUSH) || dlen)
|
|
/*
|
|
* There is still data to be delivered, reset
|
|
* timeout
|
|
*/
|
|
*age = fr_tcplastack;
|
|
}
|
|
/*
|
|
* We cannot detect when we go out of LAST_ACK state to CLOSED
|
|
* because that is based on the reception of ACK packets;
|
|
* ipfilter can only detect that a packet has been sent by a
|
|
* host
|
|
*/
|
|
break;
|
|
|
|
case TCPS_FIN_WAIT_2: /* 9 */
|
|
/* NOT USED */
|
|
break;
|
|
|
|
case TCPS_TIME_WAIT: /* 10 */
|
|
/* we're in 2MSL timeout now */
|
|
break;
|
|
}
|
|
}
|
|
|
|
|
|
#ifdef IPFILTER_LOG
|
|
void ipstate_log(is, type)
|
|
struct ipstate *is;
|
|
u_int type;
|
|
{
|
|
struct ipslog ipsl;
|
|
void *items[1];
|
|
size_t sizes[1];
|
|
int types[1];
|
|
|
|
ipsl.isl_type = type;
|
|
ipsl.isl_pkts = is->is_pkts;
|
|
ipsl.isl_bytes = is->is_bytes;
|
|
ipsl.isl_src = is->is_src;
|
|
ipsl.isl_dst = is->is_dst;
|
|
ipsl.isl_p = is->is_p;
|
|
ipsl.isl_v = is->is_v;
|
|
ipsl.isl_flags = is->is_flags;
|
|
if (ipsl.isl_p == IPPROTO_TCP || ipsl.isl_p == IPPROTO_UDP) {
|
|
ipsl.isl_sport = is->is_sport;
|
|
ipsl.isl_dport = is->is_dport;
|
|
if (ipsl.isl_p == IPPROTO_TCP) {
|
|
ipsl.isl_state[0] = is->is_state[0];
|
|
ipsl.isl_state[1] = is->is_state[1];
|
|
}
|
|
} else if (ipsl.isl_p == IPPROTO_ICMP)
|
|
ipsl.isl_itype = is->is_icmp.ics_type;
|
|
else {
|
|
ipsl.isl_ps.isl_filler[0] = 0;
|
|
ipsl.isl_ps.isl_filler[1] = 0;
|
|
}
|
|
items[0] = &ipsl;
|
|
sizes[0] = sizeof(ipsl);
|
|
types[0] = 0;
|
|
|
|
(void) ipllog(IPL_LOGSTATE, NULL, items, sizes, types, 1);
|
|
}
|
|
#endif
|
|
|
|
|
|
#ifdef USE_INET6
|
|
frentry_t *fr_checkicmp6matchingstate(ip, fin)
|
|
ip6_t *ip;
|
|
fr_info_t *fin;
|
|
{
|
|
register ipstate_t *is, **isp;
|
|
register u_short sport, dport;
|
|
register u_char pr;
|
|
struct icmp6_hdr *ic, *oic;
|
|
union i6addr dst, src;
|
|
u_short savelen;
|
|
fr_info_t ofin;
|
|
tcphdr_t *tcp;
|
|
frentry_t *fr;
|
|
ip6_t *oip;
|
|
int type;
|
|
u_int hv;
|
|
|
|
/*
|
|
* Does it at least have the return (basic) IP header ?
|
|
* Only a basic IP header (no options) should be with
|
|
* an ICMP error header.
|
|
*/
|
|
if ((fin->fin_v != 6) || (fin->fin_plen < ICMP6ERR_MINPKTLEN))
|
|
return NULL;
|
|
ic = (struct icmp6_hdr *)fin->fin_dp;
|
|
type = ic->icmp6_type;
|
|
/*
|
|
* If it's not an error type, then return
|
|
*/
|
|
if ((type != ICMP6_DST_UNREACH) && (type != ICMP6_PACKET_TOO_BIG) &&
|
|
(type != ICMP6_TIME_EXCEEDED) && (type != ICMP6_PARAM_PROB))
|
|
return NULL;
|
|
|
|
oip = (ip6_t *)((char *)ic + ICMPERR_ICMPHLEN);
|
|
if (fin->fin_plen < sizeof(*oip))
|
|
return NULL;
|
|
|
|
if (oip->ip6_nxt == IPPROTO_ICMPV6) {
|
|
oic = (struct icmp6_hdr *)(oip + 1);
|
|
/*
|
|
* a ICMP error can only be generated as a result of an
|
|
* ICMP query, not as the response on an ICMP error
|
|
*
|
|
* XXX theoretically ICMP_ECHOREP and the other reply's are
|
|
* ICMP query's as well, but adding them here seems strange XXX
|
|
*/
|
|
if (!(oic->icmp6_type & ICMP6_INFOMSG_MASK))
|
|
return NULL;
|
|
|
|
/*
|
|
* perform a lookup of the ICMP packet in the state table
|
|
*/
|
|
hv = (pr = oip->ip6_nxt);
|
|
src.in6 = oip->ip6_src;
|
|
hv += src.in4.s_addr;
|
|
dst.in6 = oip->ip6_dst;
|
|
hv += dst.in4.s_addr;
|
|
hv += oic->icmp6_id;
|
|
hv += oic->icmp6_seq;
|
|
hv %= fr_statesize;
|
|
|
|
oip->ip6_plen = ntohs(oip->ip6_plen);
|
|
ofin.fin_v = 6;
|
|
fr_makefrip(sizeof(*oip), (ip_t *)oip, &ofin);
|
|
oip->ip6_plen = htons(oip->ip6_plen);
|
|
ofin.fin_ifp = fin->fin_ifp;
|
|
ofin.fin_out = !fin->fin_out;
|
|
ofin.fin_mp = NULL; /* if dereferenced, panic XXX */
|
|
|
|
READ_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_hnext)
|
|
if ((is->is_p == pr) &&
|
|
(oic->icmp6_id == is->is_icmp.ics_id) &&
|
|
(oic->icmp6_seq == is->is_icmp.ics_seq) &&
|
|
fr_matchsrcdst(is, src, dst, &ofin, NULL)) {
|
|
/*
|
|
* in the state table ICMP query's are stored
|
|
* with the type of the corresponding ICMP
|
|
* response. Correct here
|
|
*/
|
|
if (((is->is_type == ICMP6_ECHO_REPLY) &&
|
|
(oic->icmp6_type == ICMP6_ECHO_REQUEST)) ||
|
|
(is->is_type - 1 == oic->icmp6_type )) {
|
|
ips_stats.iss_hits++;
|
|
is->is_pkts++;
|
|
is->is_bytes += fin->fin_plen;
|
|
return is->is_rule;
|
|
}
|
|
}
|
|
RWLOCK_EXIT(&ipf_state);
|
|
|
|
return NULL;
|
|
};
|
|
|
|
if ((oip->ip6_nxt != IPPROTO_TCP) && (oip->ip6_nxt != IPPROTO_UDP))
|
|
return NULL;
|
|
tcp = (tcphdr_t *)(oip + 1);
|
|
dport = tcp->th_dport;
|
|
sport = tcp->th_sport;
|
|
|
|
hv = (pr = oip->ip6_nxt);
|
|
src.in6 = oip->ip6_src;
|
|
hv += src.in4.s_addr;
|
|
dst.in6 = oip->ip6_dst;
|
|
hv += dst.in4.s_addr;
|
|
hv += dport;
|
|
hv += sport;
|
|
hv %= fr_statesize;
|
|
/*
|
|
* we make an fin entry to be able to feed it to
|
|
* matchsrcdst note that not all fields are encessary
|
|
* but this is the cleanest way. Note further we fill
|
|
* in fin_mp such that if someone uses it we'll get
|
|
* a kernel panic. fr_matchsrcdst does not use this.
|
|
*
|
|
* watch out here, as ip is in host order and oip in network
|
|
* order. Any change we make must be undone afterwards.
|
|
*/
|
|
savelen = oip->ip6_plen;
|
|
oip->ip6_plen = ip->ip6_plen - sizeof(*ip) - ICMPERR_ICMPHLEN;
|
|
ofin.fin_v = 6;
|
|
fr_makefrip(sizeof(*oip), (ip_t *)oip, &ofin);
|
|
oip->ip6_plen = savelen;
|
|
ofin.fin_ifp = fin->fin_ifp;
|
|
ofin.fin_out = !fin->fin_out;
|
|
ofin.fin_mp = NULL; /* if dereferenced, panic XXX */
|
|
READ_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_hnext) {
|
|
/*
|
|
* Only allow this icmp though if the
|
|
* encapsulated packet was allowed through the
|
|
* other way around. Note that the minimal amount
|
|
* of info present does not allow for checking against
|
|
* tcp internals such as seq and ack numbers.
|
|
*/
|
|
if ((is->is_p == pr) && (is->is_v == 6) &&
|
|
fr_matchsrcdst(is, src, dst, &ofin, tcp)) {
|
|
fr = is->is_rule;
|
|
ips_stats.iss_hits++;
|
|
/*
|
|
* we must swap src and dst here because the icmp
|
|
* comes the other way around
|
|
*/
|
|
is->is_pkts++;
|
|
is->is_bytes += fin->fin_plen;
|
|
/*
|
|
* we deliberately do not touch the timeouts
|
|
* for the accompanying state table entry.
|
|
* It remains to be seen if that is correct. XXX
|
|
*/
|
|
RWLOCK_EXIT(&ipf_state);
|
|
return fr;
|
|
}
|
|
}
|
|
RWLOCK_EXIT(&ipf_state);
|
|
return NULL;
|
|
}
|
|
#endif
|