1 /*
2  * Simple netbios-dgm transparent proxy for in-kernel use.
3  * For use with the NAT code.
4  * $Id: ip_netbios_pxy.c,v 2.8.2.1 2005/07/15 21:56:51 darrenr Exp $
5  */
6 
7 /*-
8  * Copyright (c) 2002-2003 Paul J. Ledbetter III
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  * $Id: ip_netbios_pxy.c,v 2.8.2.1 2005/07/15 21:56:51 darrenr Exp $
33  */
34 
35 #define	IPF_NETBIOS_PROXY
36 
37 int ippr_netbios_init __P((void));
38 void ippr_netbios_fini __P((void));
39 int ippr_netbios_out __P((fr_info_t *, ap_session_t *, nat_t *));
40 
41 static	frentry_t	netbiosfr;
42 
43 int	netbios_proxy_init = 0;
44 
45 /*
46  * Initialize local structures.
47  */
48 int ippr_netbios_init()
49 {
50 	bzero((char *)&netbiosfr, sizeof(netbiosfr));
51 	netbiosfr.fr_ref = 1;
52 	netbiosfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
53 	MUTEX_INIT(&netbiosfr.fr_lock, "NETBIOS proxy rule lock");
54 	netbios_proxy_init = 1;
55 
56 	return 0;
57 }
58 
59 
60 void ippr_netbios_fini()
61 {
62 	if (netbios_proxy_init == 1) {
63 		MUTEX_DESTROY(&netbiosfr.fr_lock);
64 		netbios_proxy_init = 0;
65 	}
66 }
67 
68 
69 int ippr_netbios_out(fin, aps, nat)
70 fr_info_t *fin;
71 ap_session_t *aps;
72 nat_t *nat;
73 {
74 	char dgmbuf[6];
75 	int off, dlen;
76 	udphdr_t *udp;
77 	ip_t *ip;
78 	mb_t *m;
79 
80 	aps = aps;	/* LINT */
81 	nat = nat;	/* LINT */
82 
83 	m = fin->fin_m;
84 	dlen = fin->fin_dlen - sizeof(*udp);
85 	/*
86 	 * no net bios datagram could possibly be shorter than this
87 	 */
88 	if (dlen < 11)
89 		return 0;
90 
91 	ip = fin->fin_ip;
92 	udp = (udphdr_t *)fin->fin_dp;
93 	off = (char *)udp - (char *)ip + sizeof(*udp) + fin->fin_ipoff;
94 
95 	/*
96 	 * move past the
97 	 *	ip header;
98 	 *	udp header;
99 	 *	4 bytes into the net bios dgm header.
100 	 *  According to rfc1002, this should be the exact location of
101 	 *  the source address/port
102 	 */
103 	off += 4;
104 
105 	/* Copy NATed source Address/port*/
106 	dgmbuf[0] = (char)((ip->ip_src.s_addr     ) &0xFF);
107 	dgmbuf[1] = (char)((ip->ip_src.s_addr >> 8) &0xFF);
108 	dgmbuf[2] = (char)((ip->ip_src.s_addr >> 16)&0xFF);
109 	dgmbuf[3] = (char)((ip->ip_src.s_addr >> 24)&0xFF);
110 
111 	dgmbuf[4] = (char)((udp->uh_sport     )&0xFF);
112 	dgmbuf[5] = (char)((udp->uh_sport >> 8)&0xFF);
113 
114 	/* replace data in packet */
115 	COPYBACK(m, off, sizeof(dgmbuf), dgmbuf);
116 
117 	return 0;
118 }
119