1/*
2 * Simple netbios-dgm transparent proxy for in-kernel use.
3 * For use with the NAT code.
4 * $Id$
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 * $Id$
33 */
34
35#define	IPF_NETBIOS_PROXY
36
37void ipf_p_netbios_main_load(void);
38void ipf_p_netbios_main_unload(void);
39int ipf_p_netbios_out(void *, 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 */
48void
49ipf_p_netbios_main_load(void)
50{
51	bzero((char *)&netbiosfr, sizeof(netbiosfr));
52	netbiosfr.fr_ref = 1;
53	netbiosfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
54	MUTEX_INIT(&netbiosfr.fr_lock, "NETBIOS proxy rule lock");
55	netbios_proxy_init = 1;
56}
57
58
59void
60ipf_p_netbios_main_unload(void)
61{
62	if (netbios_proxy_init == 1) {
63		MUTEX_DESTROY(&netbiosfr.fr_lock);
64		netbios_proxy_init = 0;
65	}
66}
67
68
69int
70ipf_p_netbios_out(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
71{
72	char dgmbuf[6];
73	int off, dlen;
74	udphdr_t *udp;
75	ip_t *ip;
76	mb_t *m;
77
78	aps = aps;	/* LINT */
79	nat = nat;	/* LINT */
80
81	m = fin->fin_m;
82	dlen = fin->fin_dlen - sizeof(*udp);
83	/*
84	 * no net bios datagram could possibly be shorter than this
85	 */
86	if (dlen < 11)
87		return (0);
88
89	ip = fin->fin_ip;
90	udp = (udphdr_t *)fin->fin_dp;
91	off = (char *)udp - (char *)ip + sizeof(*udp) + fin->fin_ipoff;
92
93	/*
94	 * move past the
95	 *	ip header;
96	 *	udp header;
97	 *	4 bytes into the net bios dgm header.
98	 *  According to rfc1002, this should be the exact location of
99	 *  the source address/port
100	 */
101	off += 4;
102
103	/* Copy NATed source Address/port*/
104	dgmbuf[0] = (char)((ip->ip_src.s_addr     ) &0xFF);
105	dgmbuf[1] = (char)((ip->ip_src.s_addr >> 8) &0xFF);
106	dgmbuf[2] = (char)((ip->ip_src.s_addr >> 16)&0xFF);
107	dgmbuf[3] = (char)((ip->ip_src.s_addr >> 24)&0xFF);
108
109	dgmbuf[4] = (char)((udp->uh_sport     )&0xFF);
110	dgmbuf[5] = (char)((udp->uh_sport >> 8)&0xFF);
111
112	/* replace data in packet */
113	COPYBACK(m, off, sizeof(dgmbuf), dgmbuf);
114
115	return (0);
116}
117