/*
 * Milkymist SoC (Software)
 * Copyright (C) 2007, 2008, 2009, 2010, 2012 Sebastien Bourdeauducq
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <string.h>

#include "microudp.h"
#include "tftp.h"

#define PORT_OUT	69
#define PORT_IN		7642

static int format_request(char *buf, const char *filename)
{
	*buf++ = 0x00; /* Opcode: Request */
	*buf++ = 0x01;
	strcpy(buf, filename);
	buf += strlen(filename);
	*buf++ = 0x00;
	*buf++ = 'o';
	*buf++ = 'c';
	*buf++ = 't';
	*buf++ = 'e';
	*buf++ = 't';
	*buf++ = 0x00;
	return 9+strlen(filename);
}

static int format_ack(char *buf, unsigned short block)
{
	*buf++ = 0x00; /* Opcode: Ack */
	*buf++ = 0x04;
	*buf++ = (block & 0xff00) >> 8;
	*buf++ = (block & 0x00ff);
	return 4;
}

static char *packet_data;
static int total_length;
static int transfer_finished;
static char *dst_buffer;

static void rx_callback(unsigned int src_ip, unsigned short src_port, unsigned short dst_port, void *_data, unsigned int length)
{
	unsigned char *data = (unsigned char *)_data;
	unsigned short opcode;
	unsigned short block;
	int i;
	int offset;
	
	if(length < 4) return;
	if(dst_port != PORT_IN) return;
	opcode = ((unsigned short)(data[0]) << 8)|((unsigned short)(data[1]));
	block = ((unsigned short)(data[2]) << 8)|((unsigned short)(data[3]));
	if(block < 1) return;
	if(opcode == 3) { /* Data */
		length -= 4;
		offset = (block-1)*512;
		for(i=0;i<length;i++)
			dst_buffer[offset+i] = data[i+4];
		total_length += length;
		if(length < 512)
			transfer_finished = 1;
		
		length = format_ack(packet_data, block);
		microudp_send(PORT_IN, src_port, length);
	}
	if(opcode == 5) { /* Error */
		total_length = -1;
		transfer_finished = 1;
	}
}

int tftp_get(unsigned int ip, const char *filename, char *buffer)
{
	int len;
	int tries;
	int i;
	int length_before;
	
	if(!microudp_arp_resolve(ip))
		return -1;

	microudp_set_callback(rx_callback);

	packet_data = microudp_get_tx_buffer();
	dst_buffer = buffer;

	total_length = 0;
	transfer_finished = 0;
	tries = 5;
	while(1) {
		len = format_request(packet_data, filename);
		microudp_send(PORT_IN, PORT_OUT, len);
		for(i=0;i<2000000;i++) {
			microudp_service();
			if((total_length > 0) || transfer_finished) break;
		}
		if((total_length > 0) || transfer_finished) break;
		tries--;
		if(tries == 0) {
			microudp_set_callback(NULL);
			return -1;
		}
	}

	length_before = total_length;
	while(!transfer_finished) {
		if(length_before != total_length) {
			i = 12000000;
			length_before = total_length;
		}
		if(i-- == 0) {
			microudp_set_callback(NULL);
			return -1;
		}
		microudp_service();
	}

	microudp_set_callback(NULL);

	return total_length;
}