// -------------------------------------------------------------------------
// ethernet.c
//
//  21.12.2003, J. Ahrensfeld
//
// -------------------------------------------------------------------------
#include "libsys.h"
#include "ethernet.h"
#include "ipv4.h"
#include "string.h"

#define	IPV4_HEADER_SIZE		20

// -------------------------------------------------------------------------
// Testing - not the final API
uint8_t *IPV4_create(packet_t *pPacket, uint16_t proto, uint16_t len, uint8_t *inet_addr_src, uint8_t *inet_addr_dst)
{
	IPV4 *pIPv4_hdr;

	pIPv4_hdr = (IPV4*)Eth_pkt_buffer_get(pPacket);

	memset(pIPv4_hdr, 0, sizeof(IPV4));

	memcpy(pIPv4_hdr->inet_addr_src, inet_addr_src, 4);
	memcpy(pIPv4_hdr->inet_addr_dst, inet_addr_dst, 4);

	pIPv4_hdr->ver_ihl = 0x45;
	pIPv4_hdr->tos = 0x00;
	pIPv4_hdr->len = sizeof(IPV4) + len;
	pIPv4_hdr->id = 0x1234;
	pIPv4_hdr->flag_foff = 0; //IPV4_FLAG_DF;
	pIPv4_hdr->ttl = 0x10;
	pIPv4_hdr->proto = proto;

	pIPv4_hdr->hdr_chksum = 0x0000;
	pIPv4_hdr->hdr_chksum = ~IPv4ChkSum((uint16_t*)pIPv4_hdr, 0, sizeof(IPV4));

	// Send it
	return Eth_pkt_append(pPacket, sizeof(IPV4));

}

// -------------------------------------------------------------------------
uint16_t IPv4ChkSum(uint16_t *pBuf, uint16_t acc, uint16_t len)
{
	while(len > 1)
	{
		acc += *pBuf;
		if(acc < *pBuf)
			acc++;

	    ++pBuf;
		len -= 2;
	}

	/* add up any odd byte */
	if(len == 1)
	{
		acc += htons(((uint16_t)(*(uint8_t *)pBuf)) << 8);
		if(acc < htons(((uint16_t)(*(uint8_t *)pBuf)) << 8))
			acc++;
	}
	return acc;
}