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/*
* Copyright (c) 2007
* Shrew Soft Inc. 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.
* 3. Redistributions in any form must be accompanied by information on
* how to obtain complete source code for the software and any
* accompanying software that uses the software. The source code
* must either be included in the distribution or be available for no
* more than the cost of distribution plus a nominal fee, and must be
* freely redistributable under reasonable conditions. For an
* executable file, complete source code means the source code for all
* modules it contains. It does not include source code for modules or
* files that typically accompany the major components of the operating
* system on which the executable file runs.
*
* THIS SOFTWARE IS PROVIDED BY SHREW SOFT INC ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
* NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL SHREW SOFT INC
* 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.
*
* AUTHOR : Matthew Grooms
* mgrooms@shrew.net
*
*/
#include "libip.h"
uint16_t _PACKET_UDP::checksum( in_addr addr_src, in_addr addr_dst )
{
unsigned char * data = data_buff;
size_t size = data_size;
size_t oset = 0;
uint32_t cksum = 0;
for( ; ( oset + 1 ) < size; oset += 2 )
{
cksum += ( ( data[ oset ] << 8 ) & 0xff00 );
cksum += ( data[ oset + 1 ] & 0x00ff );
}
if( oset < size )
cksum += ( ( data[ oset ] << 8 ) & 0xff00 );
cksum += htons( ( uint16_t ) ( addr_src.s_addr >> 16 ) & 0xffff );
cksum += htons( ( uint16_t ) addr_src.s_addr & 0xffff );
cksum += htons( ( uint16_t ) ( addr_dst.s_addr >> 16 ) & 0xffff );
cksum += htons( ( uint16_t ) addr_dst.s_addr & 0xffff );
cksum += PROTO_IP_UDP;
cksum += size;
while( cksum >> 16 )
cksum = ( cksum & 0xffff ) + ( cksum >> 16 );
return htons( ( uint16_t ) ~cksum );
}
bool _PACKET_UDP::read( unsigned short & port_src, unsigned short & port_dst )
{
data_oset = 0;
if( data_size < ( long ) sizeof( UDP_HEADER ) )
return false;
UDP_HEADER udp_header;
get( &udp_header, sizeof( udp_header ) );
port_src = udp_header.port_src;
port_dst = udp_header.port_dst;
return true;
}
bool _PACKET_UDP::write( unsigned short port_src, unsigned short port_dst )
{
del();
UDP_HEADER udp_header;
udp_header.port_src = port_src;
udp_header.port_dst = port_dst;
udp_header.size = 0;
udp_header.checksum = 0;
return ins( &udp_header, sizeof( udp_header ) );
}
bool _PACKET_UDP::done( in_addr addr_src, in_addr addr_dst )
{
//
// sanity checks
//
if( data_size < ( long ) sizeof( UDP_HEADER ) )
return false;
//
// write size and calc checksum
//
UDP_HEADER * udp_header = ( UDP_HEADER * ) data_buff;
udp_header->size = htons( ( unsigned short ) data_size );
udp_header->checksum = 0;
udp_header->checksum = checksum( addr_src, addr_dst );
return true;
}
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