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 2005/08/20 13:48:23 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 2005/08/20 13:48:23 darrenr Exp $
33 */
34
35#define	IPF_NETBIOS_PROXY
36
37int ippr_netbios_init __P((void));
38void ippr_netbios_fini __P((void));
39int ippr_netbios_out __P((fr_info_t *, ap_session_t *, nat_t *));
40
41static	frentry_t	netbiosfr;
42
43int	netbios_proxy_init = 0;
44
45/*
46 * Initialize local structures.
47 */
48int 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
60void 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
69int ippr_netbios_out(fin, aps, nat)
70fr_info_t *fin;
71ap_session_t *aps;
72nat_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