contrib/ipfilter/ip_netbios_pxy.c

   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 1.1.2.3 2002/01/09 09:28:37 darrenr Exp $
   5  */
   6
   7 /*-
   8  * Copyright (c) 2002 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 1.1.2.3 2002/01/09 09:28:37 darrenr Exp $
  33  */
  34
  35 #define IPF_NETBIOS_PROXY
  36
  37 int ippr_netbios_init __P((void));
  38 int ippr_netbios_out __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
  39
  40 static  frentry_t       netbiosfr;
  41
  42 /*
  43  * Initialize local structures.
  44  */
  45 int ippr_netbios_init()
  46 {
  47         bzero((char *)&netbiosfr, sizeof(netbiosfr));
  48         netbiosfr.fr_ref = 1;
  49         netbiosfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
  50         return 0;
  51 }
  52
  53 int ippr_netbios_out(fin, ip, aps, nat)
  54 fr_info_t *fin;
  55 ip_t *ip;
  56 ap_session_t *aps;
  57 nat_t *nat;
  58 {
  59         char dgmbuf[6];
  60
  61         int off, dlen;
  62         udphdr_t *udp;
  63         mb_t *m;
  64
  65         m = *(mb_t **)fin->fin_mp;
  66         off = fin->fin_hlen + sizeof(udphdr_t);
  67 #if SOLARIS
  68         dlen = msgdsize(m);
  69 #else
  70         dlen = mbufchainlen(m);
  71 #endif
  72         dlen -= off;
  73
  74         /*
  75          * no net bios datagram could possibly be shorter than this
  76          */
  77         if (dlen < 11)
  78                 return 0;
  79
  80         udp = (udphdr_t *)fin->fin_dp;
  81
  82         /*
  83          * move past the
  84          *      ip header;
  85          *      udp header;
  86          *      4 bytes into the net bios dgm header.
  87          *  According to rfc1002, this should be the exact location of
  88          *  the source address/port
  89          */
  90         off += 4;
  91
  92         /* Copy NATed source Address/port*/
  93         dgmbuf[0] = (char)((ip->ip_src.s_addr     ) &0xFF);
  94         dgmbuf[1] = (char)((ip->ip_src.s_addr >> 8) &0xFF);
  95         dgmbuf[2] = (char)((ip->ip_src.s_addr >> 16)&0xFF);
  96         dgmbuf[3] = (char)((ip->ip_src.s_addr >> 24)&0xFF);
  97
  98         dgmbuf[4] = (char)((udp->uh_sport     )&0xFF);
  99         dgmbuf[5] = (char)((udp->uh_sport >> 8)&0xFF);
 100
 101         /* replace data in packet */
 102 #if SOLARIS
 103         copyin_mblk(m, off, sizeof(dgmbuf), dgmbuf);
 104 #else
 105         m_copyback(m, off, sizeof(dgmbuf), dgmbuf);
 106 #endif
 107
 108         return 0;
 109 }