594 lines
11 KiB
C
594 lines
11 KiB
C
/* $NetBSD: ip_scan.c,v 1.1.1.1 2004/03/28 08:55:43 martti Exp $ */
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/*
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* Copyright (C) 1995-2001 by Darren Reed.
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*
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* See the IPFILTER.LICENCE file for details on licencing.
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*/
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#if defined(KERNEL) || defined(_KERNEL)
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# undef KERNEL
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# undef _KERNEL
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# define KERNEL 1
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# define _KERNEL 1
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#endif
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#include <sys/param.h>
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#if defined(__hpux) && (HPUXREV >= 1111) && !defined(_KERNEL)
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# include <sys/kern_svcs.h>
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#endif
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/errno.h>
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#if !defined(_KERNEL)
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# include <stdlib.h>
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# include <string.h>
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# define _KERNEL
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# ifdef __OpenBSD__
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struct file;
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# endif
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# include <sys/uio.h>
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# undef _KERNEL
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#else
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# include <sys/systm.h>
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# if !defined(__svr4__) && !defined(__SVR4)
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# include <sys/mbuf.h>
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# endif
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#endif
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#include <sys/socket.h>
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#if !defined(__hpux) && !defined(__osf__) && !defined(linux)
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# include <sys/ioccom.h>
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#endif
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#ifdef __FreeBSD__
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# include <sys/filio.h>
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# include <sys/malloc.h>
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#else
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# include <sys/ioctl.h>
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#endif
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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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#include <net/if.h>
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#include "netinet/ip_compat.h"
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#include "netinet/ip_fil.h"
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#include "netinet/ip_state.h"
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#include "netinet/ip_scan.h"
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/* END OF INCLUDES */
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#if !defined(lint)
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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_scan.c,v 2.40 2004/01/27 00:24:56 darrenr Exp";
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#endif
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#ifdef IPFILTER_SCAN /* endif at bottom of file */
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ipscan_t *ipsc_list = NULL,
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*ipsc_tail = NULL;
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ipscanstat_t ipsc_stat;
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# ifdef USE_MUTEXES
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ipfrwlock_t ipsc_rwlock;
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# endif
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# ifndef isalpha
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# define isalpha(x) (((x) >= 'A' && 'Z' >= (x)) || \
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((x) >= 'a' && 'z' >= (x)))
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# endif
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int ipsc_add __P((caddr_t));
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int ipsc_delete __P((caddr_t));
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struct ipscan *ipsc_lookup __P((char *));
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int ipsc_matchstr __P((sinfo_t *, char *, int));
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int ipsc_matchisc __P((ipscan_t *, ipstate_t *, int, int, int *));
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int ipsc_match __P((ipstate_t *));
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int ipsc_init()
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{
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RWLOCK_INIT(&ipsc_rwlock, "ip scan rwlock");
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return 0;
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}
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void fr_scanunload()
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{
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RW_DESTROY(&ipsc_rwlock);
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}
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int ipsc_add(data)
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caddr_t data;
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{
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ipscan_t *i, *isc;
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int err;
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KMALLOC(isc, ipscan_t *);
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if (!isc)
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return ENOMEM;
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err = copyinptr(data, isc, sizeof(*isc));
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if (err)
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return err;
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WRITE_ENTER(&ipsc_rwlock);
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i = ipsc_lookup(isc->ipsc_tag);
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if (i) {
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RWLOCK_EXIT(&ipsc_rwlock);
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KFREE(isc);
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return EEXIST;
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}
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if (ipsc_tail) {
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ipsc_tail->ipsc_next = isc;
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isc->ipsc_pnext = &ipsc_tail->ipsc_next;
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ipsc_tail = isc;
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} else {
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ipsc_list = isc;
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ipsc_tail = isc;
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isc->ipsc_pnext = &ipsc_list;
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}
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isc->ipsc_next = NULL;
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isc->ipsc_hits = 0;
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isc->ipsc_fref = 0;
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isc->ipsc_sref = 0;
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isc->ipsc_active = 0;
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ipsc_stat.iscs_entries++;
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RWLOCK_EXIT(&ipsc_rwlock);
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return 0;
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}
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int ipsc_delete(data)
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caddr_t data;
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{
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ipscan_t isc, *i;
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int err;
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err = copyinptr(data, &isc, sizeof(isc));
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if (err)
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return err;
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WRITE_ENTER(&ipsc_rwlock);
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i = ipsc_lookup(isc.ipsc_tag);
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if (i == NULL)
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err = ENOENT;
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else {
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if (i->ipsc_fref) {
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RWLOCK_EXIT(&ipsc_rwlock);
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return EBUSY;
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}
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*i->ipsc_pnext = i->ipsc_next;
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if (i->ipsc_next)
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i->ipsc_next->ipsc_pnext = i->ipsc_pnext;
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else {
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if (i->ipsc_pnext == &ipsc_list)
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ipsc_tail = NULL;
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else
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ipsc_tail = *(*i->ipsc_pnext)->ipsc_pnext;
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}
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ipsc_stat.iscs_entries--;
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KFREE(i);
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}
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RWLOCK_EXIT(&ipsc_rwlock);
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return err;
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}
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struct ipscan *ipsc_lookup(tag)
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char *tag;
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{
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ipscan_t *i;
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for (i = ipsc_list; i; i = i->ipsc_next)
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if (!strcmp(i->ipsc_tag, tag))
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return i;
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return NULL;
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}
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int ipsc_attachfr(fr)
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struct frentry *fr;
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{
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ipscan_t *i;
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if (fr->fr_isctag[0]) {
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READ_ENTER(&ipsc_rwlock);
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i = ipsc_lookup(fr->fr_isctag);
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if (i != NULL) {
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ATOMIC_INC32(i->ipsc_fref);
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}
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RWLOCK_EXIT(&ipsc_rwlock);
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if (i == NULL)
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return ENOENT;
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fr->fr_isc = i;
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}
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return 0;
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}
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int ipsc_attachis(is)
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struct ipstate *is;
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{
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frentry_t *fr;
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ipscan_t *i;
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READ_ENTER(&ipsc_rwlock);
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fr = is->is_rule;
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if (fr) {
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i = fr->fr_isc;
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if (!i || (i != (ipscan_t *)-1)) {
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is->is_isc = i;
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if (i) {
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ATOMIC_INC32(i->ipsc_sref);
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if (i->ipsc_clen)
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is->is_flags |= IS_SC_CLIENT;
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else
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is->is_flags |= IS_SC_MATCHC;
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if (i->ipsc_slen)
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is->is_flags |= IS_SC_SERVER;
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else
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is->is_flags |= IS_SC_MATCHS;
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} else
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is->is_flags |= (IS_SC_CLIENT|IS_SC_SERVER);
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}
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}
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RWLOCK_EXIT(&ipsc_rwlock);
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return 0;
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}
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int ipsc_detachfr(fr)
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struct frentry *fr;
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{
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ipscan_t *i;
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i = fr->fr_isc;
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if (i != NULL) {
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ATOMIC_DEC32(i->ipsc_fref);
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}
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return 0;
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}
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int ipsc_detachis(is)
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struct ipstate *is;
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{
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ipscan_t *i;
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READ_ENTER(&ipsc_rwlock);
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if ((i = is->is_isc) && (i != (ipscan_t *)-1)) {
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ATOMIC_DEC32(i->ipsc_sref);
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is->is_isc = NULL;
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is->is_flags &= ~(IS_SC_CLIENT|IS_SC_SERVER);
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}
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RWLOCK_EXIT(&ipsc_rwlock);
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return 0;
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}
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/*
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* 'string' compare for scanning
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*/
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int ipsc_matchstr(sp, str, n)
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sinfo_t *sp;
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char *str;
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int n;
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{
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char *s, *t, *up;
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int i = n;
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if (i > sp->s_len)
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i = sp->s_len;
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up = str;
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for (s = sp->s_txt, t = sp->s_msk; i; i--, s++, t++, up++)
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switch ((int)*t)
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{
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case '.' :
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if (*s != *up)
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return 1;
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break;
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case '?' :
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if (!isalpha(*up) || ((*s & 0x5f) != (*up & 0x5f)))
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return 1;
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break;
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case '*' :
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break;
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}
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return 0;
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}
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/*
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* Returns 3 if both server and client match, 2 if just server,
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* 1 if just client
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*/
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int ipsc_matchisc(isc, is, cl, sl, maxm)
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ipscan_t *isc;
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ipstate_t *is;
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int cl, sl, maxm[2];
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{
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int i, j, k, n, ret = 0, flags;
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flags = is->is_flags;
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/*
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* If we've already matched more than what is on offer, then
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* assume we have a better match already and forget this one.
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*/
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if (maxm != NULL) {
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if (isc->ipsc_clen < maxm[0])
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return 0;
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if (isc->ipsc_slen < maxm[1])
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return 0;
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j = maxm[0];
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k = maxm[1];
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} else {
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j = 0;
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k = 0;
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}
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if (!isc->ipsc_clen)
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ret = 1;
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else if (((flags & (IS_SC_MATCHC|IS_SC_CLIENT)) == IS_SC_CLIENT) &&
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cl && isc->ipsc_clen) {
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i = 0;
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n = MIN(cl, isc->ipsc_clen);
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if ((n > 0) && (!maxm || (n >= maxm[1]))) {
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if (!ipsc_matchstr(&isc->ipsc_cl, is->is_sbuf[0], n)) {
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i++;
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ret |= 1;
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if (n > j)
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j = n;
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}
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}
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}
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if (!isc->ipsc_slen)
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ret |= 2;
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else if (((flags & (IS_SC_MATCHS|IS_SC_SERVER)) == IS_SC_SERVER) &&
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sl && isc->ipsc_slen) {
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i = 0;
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n = MIN(cl, isc->ipsc_slen);
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if ((n > 0) && (!maxm || (n >= maxm[1]))) {
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if (!ipsc_matchstr(&isc->ipsc_sl, is->is_sbuf[1], n)) {
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i++;
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ret |= 2;
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if (n > k)
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k = n;
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}
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}
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}
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if (maxm && (ret == 3)) {
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maxm[0] = j;
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maxm[1] = k;
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}
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return ret;
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}
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int ipsc_match(is)
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ipstate_t *is;
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{
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int i, j, k, n, cl, sl, maxm[2];
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ipscan_t *isc, *lm;
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tcpdata_t *t;
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for (cl = 0, n = is->is_smsk[0]; n & 1; n >>= 1)
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cl++;
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for (sl = 0, n = is->is_smsk[1]; n & 1; n >>= 1)
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sl++;
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j = 0;
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isc = is->is_isc;
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if (isc != NULL) {
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/*
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* Known object to scan for.
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*/
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i = ipsc_matchisc(isc, is, cl, sl, NULL);
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if (i & 1) {
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is->is_flags |= IS_SC_MATCHC;
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is->is_flags &= ~IS_SC_CLIENT;
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} else if (cl >= isc->ipsc_clen)
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is->is_flags &= ~IS_SC_CLIENT;
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if (i & 2) {
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is->is_flags |= IS_SC_MATCHS;
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is->is_flags &= ~IS_SC_SERVER;
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} else if (sl >= isc->ipsc_slen)
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is->is_flags &= ~IS_SC_SERVER;
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} else {
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i = 0;
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lm = NULL;
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maxm[0] = 0;
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maxm[1] = 0;
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for (k = 0, isc = ipsc_list; isc; isc = isc->ipsc_next) {
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i = ipsc_matchisc(isc, is, cl, sl, maxm);
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if (i) {
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/*
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* We only want to remember the best match
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* and the number of times we get a best
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* match.
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*/
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if ((j == 3) && (i < 3))
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continue;
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if ((i == 3) && (j != 3))
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k = 1;
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else
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k++;
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j = i;
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lm = isc;
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}
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}
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if (k == 1)
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isc = lm;
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/*
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* No matches or partial matches, so reset the respective
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* search flag.
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*/
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if (!(j & 1))
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is->is_flags &= ~IS_SC_CLIENT;
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if (!(j & 2))
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is->is_flags &= ~IS_SC_SERVER;
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/*
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* If we found the best match, then set flags appropriately.
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*/
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if ((j == 3) && (k == 1)) {
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is->is_flags &= ~(IS_SC_SERVER|IS_SC_CLIENT);
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is->is_flags |= (IS_SC_MATCHS|IS_SC_MATCHC);
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}
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}
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/*
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* If the acknowledged side of a connection has moved past the data in
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* which we are interested, then reset respective flag.
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*/
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t = &is->is_tcp.ts_data[0];
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if (t->td_end > is->is_s0[0] + 15)
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is->is_flags &= ~IS_SC_CLIENT;
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t = &is->is_tcp.ts_data[1];
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if (t->td_end > is->is_s0[1] + 15)
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is->is_flags &= ~IS_SC_SERVER;
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/*
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* Matching complete ?
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*/
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j = ISC_A_NONE;
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if ((is->is_flags & IS_SC_MATCHALL) == IS_SC_MATCHALL) {
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j = isc->ipsc_action;
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ipsc_stat.iscs_acted++;
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} else if ((is->is_isc != NULL) &&
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((is->is_flags & IS_SC_MATCHALL) != IS_SC_MATCHALL) &&
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!(is->is_flags & (IS_SC_CLIENT|IS_SC_SERVER))) {
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/*
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* Matching failed...
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*/
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j = isc->ipsc_else;
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ipsc_stat.iscs_else++;
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}
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switch (j)
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{
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case ISC_A_CLOSE :
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/*
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* If as a result of a successful match we are to
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* close a connection, change the "keep state" info.
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* to block packets and generate TCP RST's.
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*/
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is->is_pass &= ~FR_RETICMP;
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is->is_pass |= FR_RETRST;
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break;
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default :
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break;
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}
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return i;
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}
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/*
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* check if a packet matches what we're scanning for
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*/
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int ipsc_packet(fin, is)
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fr_info_t *fin;
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ipstate_t *is;
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{
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int i, j, rv, dlen, off, thoff;
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u_32_t seq, s0;
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tcphdr_t *tcp;
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rv = !IP6_EQ(&fin->fin_fi.fi_src, &is->is_src);
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tcp = fin->fin_dp;
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seq = ntohl(tcp->th_seq);
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if (!is->is_s0[rv])
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return 1;
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/*
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* check if this packet has more data that falls within the first
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* 16 bytes sent in either direction.
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*/
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s0 = is->is_s0[rv];
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off = seq - s0;
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if ((seq > s0 + 15) || (off < 0))
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return 1;
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thoff = TCP_OFF(tcp) << 2;
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dlen = fin->fin_dlen - thoff;
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if (dlen <= 0)
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return 1;
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seq += dlen;
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if (seq > s0 + 15)
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dlen -= (seq - (s0 + 15));
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j = 0xffff >> (16 - dlen);
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i = (0xffff & j) << off;
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#ifdef _KERNEL
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COPYDATA(*(mb_t **)fin->fin_mp, fin->fin_hlen + thoff, dlen,
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(caddr_t)is->is_sbuf[rv] + off);
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#endif
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is->is_smsk[rv] |= i;
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for (j = 0, i = is->is_smsk[rv]; i & 1; i >>= 1)
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j++;
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if (j == 0)
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return 1;
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(void) ipsc_match(is);
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#if 0
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/*
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* There is the potential here for plain text passwords to get
|
|
* buffered and stored for some time...
|
|
*/
|
|
if (!(is->is_flags & IS_SC_CLIENT))
|
|
bzero(is->is_sbuf[0], sizeof(is->is_sbuf[0]));
|
|
if (!(is->is_flags & IS_SC_SERVER))
|
|
bzero(is->is_sbuf[1], sizeof(is->is_sbuf[1]));
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
|
|
int fr_scan_ioctl(data, cmd, mode)
|
|
caddr_t data;
|
|
ioctlcmd_t cmd;
|
|
int mode;
|
|
{
|
|
ipscanstat_t ipscs;
|
|
int err = 0;
|
|
|
|
switch (cmd)
|
|
{
|
|
case SIOCADSCA :
|
|
err = ipsc_add(data);
|
|
break;
|
|
case SIOCRMSCA :
|
|
err = ipsc_delete(data);
|
|
break;
|
|
case SIOCGSCST :
|
|
bcopy((char *)&ipsc_stat, (char *)&ipscs, sizeof(ipscs));
|
|
ipscs.iscs_list = ipsc_list;
|
|
BCOPYOUT(&ipscs, data, sizeof(ipscs));
|
|
break;
|
|
default :
|
|
err = EINVAL;
|
|
break;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
#endif /* IPFILTER_SCAN */
|