ip.c

深圳优龙公司LPC2292开发板的BIOS源码和测试程序

#include "../../inc/config.h"
#include "skbuff.h"
#include "eth.h"
#include "ip.h"
#include "arp.h"
#include "icmp.h"
#include "udp.h"
#include "utils.h"

#ifdef	TFTP_DOWNLOAD_SUPPORT

static unsigned long local_ip = 0;

unsigned short ip_fast_csum( unsigned char* iph , unsigned int ihl )
{
	unsigned int sum, tmp1;

	// ip_fast_csum
	__asm
	{
		ldr	sum, [iph], #4		
		ldr	tmp1, [iph], #4
		sub	ihl, ihl, #5
		adds	sum, sum, tmp1
		ldr	tmp1, [iph], #4
		adcs	sum, sum, tmp1
		ldr	tmp1, [iph], #4
		adcs	sum, sum, tmp1
		l:	ldr	tmp1, [iph], #4
		adcs	sum, sum, tmp1
		tst	ihl, #15
		subne	ihl, ihl, #1
		bne	l
		adc	sum, sum, #0
		adds	sum, sum, sum, lsl #16
		addcs	sum, sum, #0x10000
		mvn	sum, sum
		mov	sum, sum, lsr #16	

	};

	return sum;
} 

int ip_init( unsigned long ip )
{
	local_ip = ip;
	return 0;
}

int ip_rcv_packet( struct sk_buff* skb )
{
	struct iphdr* ip_hdr = ( struct iphdr* ) ( skb->data );

	if ( ntohl( ip_hdr->daddr ) == local_ip )
	{
		skb->len = ntohs( ip_hdr->tot_len );
		skb_pull( skb , sizeof( struct iphdr ) );

		if ( ip_hdr->protocol == UDP )
			udp_rcv_packet( skb );
		if ( ip_hdr->protocol == ICMP )
			icmp_rcv_packet( skb );
	}

	return 0;
}

int ip_send( struct sk_buff* skb , unsigned long ip , unsigned char proto )
{
	struct iphdr* ip_hdr;
	static unsigned short ip_id = 32;	
	unsigned char dest_eth_addr[ETH_ALEN];	

	if ( arp_get_eth_addr( ip , dest_eth_addr ) )
		return -1;

	ip_hdr = ( struct iphdr * ) skb_push( skb , sizeof( struct iphdr ) );

	ip_hdr->ihl = 5;
	ip_hdr->version = 4;
	ip_hdr->tos = 0;
	//	ip_hdr->tot_len = htons(32);
	ip_hdr->tot_len = htons( skb->len );	
	ip_hdr->id = htons( ip_id++ );
	ip_hdr->frag_off = 0;
	ip_hdr->ttl = 20;
	ip_hdr->protocol = proto;
	ip_hdr->check = 0;
	ip_hdr->saddr = htonl( local_ip );
	ip_hdr->daddr = htonl( ip );	
	ip_hdr->check = ip_fast_csum( ( unsigned char * ) ip_hdr , ip_hdr->ihl );

	eth_send( skb , dest_eth_addr , ETH_P_IP );

	return 0;
}

void ip_skb_reserve( struct sk_buff* skb )
{
	eth_skb_reserve( skb );
	skb_reserve( skb , sizeof( struct iphdr ) );
}

unsigned long ip_get_source_ip( struct sk_buff* skb )
{
	struct iphdr* ip_hdr;

	ip_hdr = ( struct iphdr * ) ( skb->buf + ETH_HLEN );
	return ntohl( ip_hdr->saddr );
}

#endif