/*
 * Simple netbios-dgm transparent proxy for in-kernel use.
 * For use with the NAT code.
 * $Id$
 */

/*-
 * Copyright (c) 2002-2003 Paul J. Ledbetter III
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id$
 */

#define IPF_NETBIOS_PROXY

void ipf_p_netbios_main_load(void);
void ipf_p_netbios_main_unload(void);
int ipf_p_netbios_out(void *, fr_info_t *, ap_session_t *, nat_t *);

static  frentry_t       netbiosfr;

int     netbios_proxy_init = 0;

/*
 * Initialize local structures.
 */
void
ipf_p_netbios_main_load(void)
{
        bzero((char *)&netbiosfr, sizeof(netbiosfr));
        netbiosfr.fr_ref = 1;
        netbiosfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
        MUTEX_INIT(&netbiosfr.fr_lock, "NETBIOS proxy rule lock");
        netbios_proxy_init = 1;
}


void
ipf_p_netbios_main_unload(void)
{
        if (netbios_proxy_init == 1) {
                MUTEX_DESTROY(&netbiosfr.fr_lock);
                netbios_proxy_init = 0;
        }
}


int
ipf_p_netbios_out(void *arg, fr_info_t *fin, ap_session_t *aps __unused, nat_t *nat __unused)
{
        char dgmbuf[6];
        int off, dlen;
        udphdr_t *udp;
        ip_t *ip;
        mb_t *m;

        m = fin->fin_m;
        dlen = fin->fin_dlen - sizeof(*udp);
        /*
         * no net bios datagram could possibly be shorter than this
         */
        if (dlen < 11)
                return (0);

        ip = fin->fin_ip;
        udp = (udphdr_t *)fin->fin_dp;
        off = (char *)udp - (char *)ip + sizeof(*udp) + fin->fin_ipoff;

        /*
         * move past the
         *      ip header;
         *      udp header;
         *      4 bytes into the net bios dgm header.
         *  According to rfc1002, this should be the exact location of
         *  the source address/port
         */
        off += 4;

        /* Copy NATed source Address/port*/
        dgmbuf[0] = (char)((ip->ip_src.s_addr     ) &0xFF);
        dgmbuf[1] = (char)((ip->ip_src.s_addr >> 8) &0xFF);
        dgmbuf[2] = (char)((ip->ip_src.s_addr >> 16)&0xFF);
        dgmbuf[3] = (char)((ip->ip_src.s_addr >> 24)&0xFF);

        dgmbuf[4] = (char)((udp->uh_sport     )&0xFF);
        dgmbuf[5] = (char)((udp->uh_sport >> 8)&0xFF);

        /* replace data in packet */
        COPYBACK(m, off, sizeof(dgmbuf), dgmbuf);

        return (0);
}