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      1 /*	$NetBSD: ip_netbios_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $	*/
      2 
      3 /*
      4  * Simple netbios-dgm transparent proxy for in-kernel use.
      5  * For use with the NAT code.
      6  * Id: ip_netbios_pxy.c,v 1.1.1.2 2012/07/22 13:45:30 darrenr Exp
      7  */
      8 
      9 /*-
     10  * Copyright (c) 2002-2003 Paul J. Ledbetter III
     11  * All rights reserved.
     12  *
     13  * Redistribution and use in source and binary forms, with or without
     14  * modification, are permitted provided that the following conditions
     15  * are met:
     16  * 1. Redistributions of source code must retain the above copyright
     17  *    notice, this list of conditions and the following disclaimer.
     18  * 2. Redistributions in binary form must reproduce the above copyright
     19  *    notice, this list of conditions and the following disclaimer in the
     20  *    documentation and/or other materials provided with the distribution.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  * Id: ip_netbios_pxy.c,v 1.1.1.2 2012/07/22 13:45:30 darrenr Exp
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 __KERNEL_RCSID(1, "$NetBSD: ip_netbios_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $");
     39 
     40 #define	IPF_NETBIOS_PROXY
     41 
     42 void ipf_p_netbios_main_load(void);
     43 void ipf_p_netbios_main_unload(void);
     44 int ipf_p_netbios_out(void *, fr_info_t *, ap_session_t *, nat_t *);
     45 
     46 static	frentry_t	netbiosfr;
     47 
     48 int	netbios_proxy_init = 0;
     49 
     50 /*
     51  * Initialize local structures.
     52  */
     53 void
     54 ipf_p_netbios_main_load(void)
     55 {
     56 	bzero((char *)&netbiosfr, sizeof(netbiosfr));
     57 	netbiosfr.fr_ref = 1;
     58 	netbiosfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
     59 	MUTEX_INIT(&netbiosfr.fr_lock, "NETBIOS proxy rule lock");
     60 	netbios_proxy_init = 1;
     61 }
     62 
     63 
     64 void
     65 ipf_p_netbios_main_unload(void)
     66 {
     67 	if (netbios_proxy_init == 1) {
     68 		MUTEX_DESTROY(&netbiosfr.fr_lock);
     69 		netbios_proxy_init = 0;
     70 	}
     71 }
     72 
     73 
     74 int
     75 ipf_p_netbios_out(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
     76 {
     77 	char dgmbuf[6];
     78 	int off, dlen;
     79 	udphdr_t *udp;
     80 	ip_t *ip;
     81 	mb_t *m;
     82 
     83 	aps = aps;	/* LINT */
     84 	nat = nat;	/* LINT */
     85 
     86 	m = fin->fin_m;
     87 	dlen = fin->fin_dlen - sizeof(*udp);
     88 	/*
     89 	 * no net bios datagram could possibly be shorter than this
     90 	 */
     91 	if (dlen < 11)
     92 		return 0;
     93 
     94 	ip = fin->fin_ip;
     95 	udp = (udphdr_t *)fin->fin_dp;
     96 	off = (char *)udp - (char *)ip + sizeof(*udp) + fin->fin_ipoff;
     97 
     98 	/*
     99 	 * move past the
    100 	 *	ip header;
    101 	 *	udp header;
    102 	 *	4 bytes into the net bios dgm header.
    103 	 *  According to rfc1002, this should be the exact location of
    104 	 *  the source address/port
    105 	 */
    106 	off += 4;
    107 
    108 	/* Copy NATed source Address/port*/
    109 	dgmbuf[0] = (char)((ip->ip_src.s_addr     ) &0xFF);
    110 	dgmbuf[1] = (char)((ip->ip_src.s_addr >> 8) &0xFF);
    111 	dgmbuf[2] = (char)((ip->ip_src.s_addr >> 16)&0xFF);
    112 	dgmbuf[3] = (char)((ip->ip_src.s_addr >> 24)&0xFF);
    113 
    114 	dgmbuf[4] = (char)((udp->uh_sport     )&0xFF);
    115 	dgmbuf[5] = (char)((udp->uh_sport >> 8)&0xFF);
    116 
    117 	/* replace data in packet */
    118 	COPYBACK(m, off, sizeof(dgmbuf), dgmbuf);
    119 
    120 	return 0;
    121 }
    122