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 __P((void));
38 void ipf_p_netbios_main_unload __P((void));
39 int ipf_p_netbios_out __P((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()49 ipf_p_netbios_main_load()
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()60 ipf_p_netbios_main_unload()
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(arg,fin,aps,nat)70 ipf_p_netbios_out(arg, fin, aps, nat)
71 void *arg;
72 fr_info_t *fin;
73 ap_session_t *aps;
74 nat_t *nat;
75 {
76 char dgmbuf[6];
77 int off, dlen;
78 udphdr_t *udp;
79 ip_t *ip;
80 mb_t *m;
81
82 aps = aps; /* LINT */
83 nat = nat; /* LINT */
84
85 m = fin->fin_m;
86 dlen = fin->fin_dlen - sizeof(*udp);
87 /*
88 * no net bios datagram could possibly be shorter than this
89 */
90 if (dlen < 11)
91 return 0;
92
93 ip = fin->fin_ip;
94 udp = (udphdr_t *)fin->fin_dp;
95 off = (char *)udp - (char *)ip + sizeof(*udp) + fin->fin_ipoff;
96
97 /*
98 * move past the
99 * ip header;
100 * udp header;
101 * 4 bytes into the net bios dgm header.
102 * According to rfc1002, this should be the exact location of
103 * the source address/port
104 */
105 off += 4;
106
107 /* Copy NATed source Address/port*/
108 dgmbuf[0] = (char)((ip->ip_src.s_addr ) &0xFF);
109 dgmbuf[1] = (char)((ip->ip_src.s_addr >> 8) &0xFF);
110 dgmbuf[2] = (char)((ip->ip_src.s_addr >> 16)&0xFF);
111 dgmbuf[3] = (char)((ip->ip_src.s_addr >> 24)&0xFF);
112
113 dgmbuf[4] = (char)((udp->uh_sport )&0xFF);
114 dgmbuf[5] = (char)((udp->uh_sport >> 8)&0xFF);
115
116 /* replace data in packet */
117 COPYBACK(m, off, sizeof(dgmbuf), dgmbuf);
118
119 return 0;
120 }
121