/*
 * File:		ip.c
 * Purpose:		Internet Protcol device driver
 *
 * Notes:
 *
 * Modifications:
 */


#include "src/init/m523xevb.h"
#include "src/ethernet/nif.h"
#include "src/ethernet/tftp/arp.h"
#include "src/ethernet/tftp/icmp.h"
#include "src/ethernet/tftp/ip.h"
#include "src/ethernet/tftp/udp.h"

/********************************************************************/
void
ip_init(IP_INFO *info, 
		IP_ADDR_P myip,
		IP_ADDR_P gateway,
		IP_ADDR_P netmask)
{
	int index;

	for (index = 0; index < sizeof(IP_ADDR); index++)
	{
		info->myip[index] = myip[index];
		info->gateway[index] = gateway[index];
		info->netmask[index] = netmask[index];
		info->broadcast[index] = 0xFF;
	}

	info->rx = 0;
	info->rx_unsup = 0;
	info->tx = 0;
	info->err = 0;
}

/********************************************************************/
uint8 *
ip_get_myip (IP_INFO *info)
{
	if (info != 0)
	{
		return (uint8 *)&info->myip[0];
	}
	return 0;
}

/********************************************************************/
int
ip_addr_compare (IP_ADDR_P addr1, IP_ADDR_P addr2)
{
	int i;

	for (i = 0; i < sizeof(IP_ADDR); i++)
	{
		if (addr1[i] != addr2[i])
			return 0;
	}
	return 1;
}

/********************************************************************/
uint8 *
ip_resolve_route (NIF *nif, IP_ADDR_P destip, NBUF **ppNbuf)
{
	/*
	 * This function determines whether or not an outgoing IP
	 * packet needs to be transmitted on the local net or sent
	 * to the router for transmission.
	 */
	IP_INFO *info;
	IP_ADDR	mask,result;
	int i;

	info = nif_get_protocol_info(nif,FRAME_IP);

	/* create mask for local IP */
	for (i = 0; i < sizeof(IP_ADDR); i++)
	{
		mask[i] = info->myip[i] & info->netmask[i];
	}

	/* apply mask to the destination IP */
	for (i = 0; i < sizeof(IP_ADDR); i++)
	{
		result[i] = mask[i] & destip[i];
	}

	/* See if destination IP is local or not */
	if (ip_addr_compare(mask,result))
	{
		/* The destination IP is on the local net */
		return arp_resolve(nif,FRAME_IP,destip, ppNbuf);
	}
	else
	{
		/* The destination IP is not on the local net */
		return arp_resolve(nif,FRAME_IP,info->gateway, ppNbuf);
	}
}

/******************************************************************/
int
ip_send (NIF *nif, uint8 *dest, uint8 *src,
		 uint8 protocol, NBUF *pNbuf)
{
	/*
	 * This function assembles an IP datagram and passes it
	 * onto the hardware to be sent over the network.
	 */
	uint8 *route;
	ip_frame_hdr *ipframe;
	
	/* Construct the IP header */
	ipframe = (ip_frame_hdr*)&pNbuf->data[IP_HDR_OFFSET];

	/* IP version 4, Internet Header Length of 5 32-bit words */
	ipframe->version_ihl = 0x45;

	/* Type of Service == 0, normal and routine */
	ipframe->service_type = 0x00;

	/* Total length of data */
	ipframe->total_length = (uint16)(pNbuf->length + IP_HDR_SIZE);

	/* User defined identification */
	ipframe->identification = 0x0000;

	/* Fragment Flags and Offset -- Don't fragment, last frag */
	ipframe->flags_frag_offset = 0x0000;

	/* Time To Live */
	ipframe->ttl = 0xFF;

	/* Protocol */
	ipframe->protocol = protocol;

	/* Checksum, computed later, zeroed for computation */
	ipframe->checksum = 0x0000;

	/* source IP address */
	ipframe->source_addr[0] = src[0];
	ipframe->source_addr[1] = src[1];
	ipframe->source_addr[2] = src[2];
	ipframe->source_addr[3] = src[3];

	/* dest IP address */
	ipframe->dest_addr[0] = dest[0];
	ipframe->dest_addr[1] = dest[1];
	ipframe->dest_addr[2] = dest[2];
	ipframe->dest_addr[3] = dest[3];

	/* compute checksum */
	ipframe->checksum = ip_chksum((uint16 *)ipframe,IP_HDR_SIZE);

	/* Increment the packet length appropriately */
	pNbuf->length += IP_HDR_SIZE;

	route = ip_resolve_route(nif,dest, &pNbuf);
	if (route == NULL)
	{
		printf("Unable to locate %d.%d.%d.%d\n",
			dest[0],dest[1],dest[2],dest[3]);
		nif->tx_free(pNbuf);
		return 0;
	}

	return	nif->send ( nif,
						route,
						&nif->hwa[0],
						FRAME_IP,
						pNbuf) ;
}

/******************************************************************/
#if defined(DEBUG_PRINT)
void
dump_ip_frame (ip_frame_hdr *ipframe)
{
	printf("Version:  %02X\n", ((ipframe->version_ihl & 0x00f0) >> 4));
	printf("IHL:      %02X\n", ipframe->version_ihl & 0x000f);
	printf("Service:  %02X\n", ipframe->service_type);
	printf("Length:   %04X\n", ipframe->total_length);
	printf("Ident:    %04X\n", ipframe->identification);
	printf("Flags:    %02X\n", ((ipframe->flags_frag_offset & 0xC000) >> 14));
	printf("Frag:     %04X\n", ipframe->flags_frag_offset & 0x3FFF);
	printf("TTL:      %02X\n", ipframe->ttl);
	printf("Protocol: %02X\n", ipframe->protocol);
	printf("Chksum:   %04X\n", ipframe->checksum);
	printf("Source  : %d.%d.%d.%d\n",
		ipframe->source_addr[0],
		ipframe->source_addr[1],
		ipframe->source_addr[2],
		ipframe->source_addr[3]);
	printf("Dest    : %d.%d.%d.%d\n",
		ipframe->dest_addr[0],
		ipframe->dest_addr[1],
		ipframe->dest_addr[2],
		ipframe->dest_addr[3]);
	printf("Options: %08X\n", ipframe->options);
}
#endif

/******************************************************************/
uint16
ip_chksum (uint16 *data, int num)
{
	int chksum, ichksum;
	uint16 temp;

	chksum = 0;
	num = num >> 1;	/* from bytes to words */
	for (; num; num--, data++)
	{
		temp = *data;
		ichksum = chksum + temp;
		ichksum = ichksum & 0x0000FFFF;
		if ((ichksum < temp) || (ichksum < chksum))
		{
			ichksum += 1;
			ichksum = ichksum & 0x0000FFFF;
		}
		chksum = ichksum;
	}
	return (uint16)~chksum;
}

/******************************************************************/
static int
validate_ip_hdr (NIF *nif, ip_frame_hdr *ipframe)
{
	int index, chksum;
	IP_INFO *info;

	/* Check the IP Version */
	if (IP_VERSION(ipframe) != 4)
	{
		return 0;
	}

	/* Check Internet Header Length */
	if (IP_IHL(ipframe) < 5)
	{
		return 0;
	}

	info = nif_get_protocol_info(nif,FRAME_IP);
	for (index = 0; index < sizeof(IP_ADDR); index++)
	{
		if (info->myip[index] != ipframe->dest_addr[index])
			return 0;
	}

	/* Check the checksum */
	chksum = (int)((uint16)IP_CHKSUM(ipframe));
	IP_CHKSUM(ipframe) = 0;

	if (ip_chksum((uint16 *)ipframe,IP_IHL(ipframe)*4) != chksum)
	{
		return 0;
	}
	IP_CHKSUM(ipframe) = (uint16)chksum;

	return 1;
}

/******************************************************************/
void
ip_handler (NIF *nif, NBUF *pNbuf)
{
	/* IP packet handler */
	ip_frame_hdr *ipframe;
	int hdr_offset;

	ipframe = (ip_frame_hdr *)&pNbuf->data[IP_HDR_OFFSET];

	/* Verify valid IP header and destination IP */
	if (!validate_ip_hdr(nif,ipframe))
		return;

	hdr_offset = ETH_HDR_SIZE + (IP_IHL(ipframe) * 4);
	pNbuf->length = (uint16)(IP_LENGTH(ipframe) - (IP_IHL(ipframe) * 4));

	/* Call the appriopriate handler */
	switch (IP_PROTOCOL(ipframe))
	{
		case IP_PROTO_ICMP:
			icmp_handler(nif,pNbuf,hdr_offset);
			break;
		case IP_PROTO_UDP:
			udp_handler(nif,pNbuf,hdr_offset);
			break;
		default:
			break;
	}
	return;
}

/******************************************************************/