//-------------------------------------------------------------------
//	tryarp.cpp	    (A revision of our 'nicstudy.cpp' deno)
//
//	This program (which requires our 'user8139.c' device-driver)
//	modifies the 'nicstudy.cpp' demo to transmit an ARP-request.  
//
//	programmer: ALLAN CRUSE
//	written on: 11 APR 2005
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for read(), write(), lseek()
#include <sys/mman.h>	// for mmap(), munmap()
#include <string.h>	// for memset(), memcpy(), strncpy()

char nicname[] = "/dev/nic";	// name of the device special file

void show_nic_registers( void *vm )
{
	// display the contents of io-memory in hexadecimal format
	printf( "\n\nRealTek 8139 Registers mapped at %p \n", vm );	
	unsigned long 	*lp = (unsigned long *)vm;
	for (int i = 0; i < 64; i++)
		{
		if ( ( i % 8 ) == 0 ) printf( "\n%02X: ", i*4 ); 
		printf( "%08lX ", lp[ i ] );
		}
	printf( "\n" );
}

int main( int argc, char **argv )
{
	// open the device-file
	int	fd = open( nicname, O_RDWR );
	if ( fd < 0 ) { perror( nicname ); exit(1); }

	// map the device's io-memory to user-space
	int	prot = PROT_READ | PROT_WRITE;
	int	flag = MAP_SHARED;
	int	size = 0x1000;
	int	base = 0;  
	void	*vm = mmap( NULL, size, prot, flag, fd, base );
	if ( vm == MAP_FAILED ) { perror( "mmap" ); exit(1); }
	
	// display the contents of io-memory in hexadecimal format
	show_nic_registers( vm );

	// reset the network controller
	int	io = (int)vm;
	unsigned char	*RTCommand = (unsigned char *)(io+0x37);
	unsigned long	*TxStatus0 = (unsigned long *)(io+0x10);
	unsigned long	*Tx_Config = (unsigned long *)(io+0x40);
	*RTCommand = 0x10;		// initiate the NIC reset
	while ( *RTCommand & 0x10 );	// await reset completion

	// construct an Address Resolution Protocol request-packet
	char	packet[ 64 ] = {0};
	memset( packet+0, 0xFF, 6 );	// broadcast address
	// packet type (0x0806 = Address Resolution Protocol) 
	packet[12] = 0x08;
	packet[13] = 0x06;
	// HTYPE (Hardware Type: 0x0001 = Ethernet)
	packet[14] = 0x00;
	packet[15] = 0x01;
	// PTYPE (Protocol Type: 0x0800 = IP)
	packet[16] = 0x08;
	packet[17] = 0x00;
	// HLEN (Hardware Length)
	packet[18] = 0x06;
	// PLEN (Protocol Length)
	packet[19] = 0x04;
	// OPER (ARP Request)
	packet[20] = 0x00;
	packet[21] = 0x01;
	// SHA (Source Hardware Address: lectern02.cs.usfca.edu)
	packet[22] = 0x00; 
	packet[23] = 0xE0; 
	packet[24] = 0x18; 
	packet[25] = 0x8B; 
	packet[26] = 0x2C; 
	packet[27] = 0x9E;
	// SPA (Source Protocol Address: lectern02.cs.usfca.edu)
	packet[28] = 138;
	packet[29] = 202;
	packet[30] = 171;
	packet[31] = 59;
	// THA (Target Hardware Address)
	memset( packet+32, 0x00, 6 );	// broadcast address
	// TPA (Target Protocol Address: hrn23501.cs.usfca.edu)
	packet[38] = 192;
	packet[39] = 168;
	packet[40] = 171;
	packet[41] = 1;
	memcpy( packet+6, packet+22, 6 );  // source address

	// place our network packet into the kernel buffer 
	lseek( fd, 0, SEEK_SET );	// point to TxBuffer0
	int 	nbytes = write( fd, packet, sizeof(packet) );	

	// then ask the RTL-8139 to transmit that packet
	*RTCommand = 0x04;	// enable TX
	*Tx_Config = 0;		// configure TX
	*TxStatus0 = 64;	// transmit TxBuffer0

	// poll the 'OWN' bit in the Transmit Descriptor Status
	while ( (*TxStatus0 & 0xC000) == 0 ); 	
	if ( (*TxStatus0 & 0xE000) == 0xA000 )
		printf( "Packet was successfully transmitted\n" );
	else	printf( "Packet encountered transmit failure\n" );
}