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
37 void ipf_p_netbios_main_load(void);
38 void ipf_p_netbios_main_unload(void);
39 int ipf_p_netbios_out(void *, 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 void
ipf_p_netbios_main_load(void)49 ipf_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
59 void
ipf_p_netbios_main_unload(void)60 ipf_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
69 int
ipf_p_netbios_out(void * arg,fr_info_t * fin,ap_session_t * aps,nat_t * nat)70 ipf_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