ip.c

来自「我自己写的一个tcp/ip的代码」· C语言 代码 · 共 47 行

#include "eth_typedef.h"
#include "cksum.h"
#include "string.h"
#include "tcp.h"

void ip_send()
{
}

void ip_handle(unsigned char * input)
{
	IP_HEADER * ip;
	unsigned int header_len;
	unsigned int reload_len;
	ip = (IP_HEADER *)(input+14);
	if(ip->dest_ip_address != my.ip_address)
	{
		return;
	}
	if((ip->ver_len >> 4) != IP_VER)
	{
		return;
	}
	header_len = 4 * (0x0f & ip->ver_len);
	reload_len = ip->total_length - header_len;
	if(cksum((unsigned char *)ip, header_len) != 0xffff)
	{
		return;
	}
	if((ip->fragment_info & 0x3fff) != 0)
	{
		return;
	}
	if(header_len > 20)
	{
		memmove((ip+20), (ip+header_len), reload_len);
		header_len = 20;
		ip->ver_len = 0x45;
		ip->total_length = reload_len + 20;
	}
	switch(ip->protocol_id)
	{
	case TCP_TYPE:
		tcp_handle((unsigned char *)ip, reload_len);
		break;
	}
}