ip.c

这是基于TI公司的DSP TMS320DM642而开发的TCP/UDP协议

#include "skbuff.h"
#include "eth.h"
#include "ip.h"
#include "arp.h"
#include "icmp.h"
#include "udp.h"
#include "netsocket.h"
#include "csl.h"
#include "tcp/tcp.h"

static Uint32 local_ip = 0;

Uint8  *pgRcvBuff;

unsigned short ip_fast_csum(void *iph, Uint32 ihl)
{
	unsigned int sum;
	Uint16 *tmp;

    tmp=(Uint16*)iph;
    sum=0;
    while(ihl>1)
    {
        sum=sum+(*tmp); 
        tmp++;
        ihl=ihl-2;   
    }

    if(ihl) 
    {
        sum+=*(Uint8*)tmp;
    }
    
    sum=(sum & 0xffff) +(sum >> 16);

	return (Uint16)(~sum);
} 

int ip_init(Uint32 ip)
{
	local_ip = ip;
	return 0;
}

int ip_rcv_packet(struct sk_buff *skb)
{
	struct iphdr *ip_hdr = (struct iphdr *)(skb->data);
    Uint32 i;
    struct pbuf *p;
 
    i=ip_hdr->daddr[3];
    i=(i<<8);
    i=i+ip_hdr->daddr[2];
    i=(i<<8);
    i=i+ip_hdr->daddr[1];
    i=(i<<8);
    i=i+ip_hdr->daddr[0];
    if (ntohl(i) == local_ip)
	{
        if(ip_fast_csum(ip_hdr,ip_hdr->ihl*4)!=0)
        {
            return -1;
        }
		if (ip_hdr->protocol == UDP)
		{   
		    pgRcvBuff=skb->data;
		    MsgAsynEvent(FD_READ);
	    }
		if(ip_hdr->protocol == ICMP)
		{
		    
		    i=ip_hdr->tot_len[1];
		    i=(i<<8);
		    i=i+ip_hdr->tot_len[0];
		    skb->len = ntohs(i);
		    skb_pull(skb, sizeof(struct iphdr));
		    
			icmp_rcv_packet(skb);
		}
		if(ip_hdr->protocol==TCP)
		{
		    i=ip_hdr->tot_len[1];
		    i=(i<<8);
		    i=i+ip_hdr->tot_len[0];
		    skb->len = ntohs(i);
 		    p = pbuf_alloc(PBUF_TRANSPORT, skb->len, PBUF_RAM);
		    if (p == NULL) 
		    {
			      return -1;
		    }
		    memcpy(p->payload,skb->data,skb->len);
		    tcp_input(p);    
		}			
	}

	return 0;
}

int ip_send(struct sk_buff *skb, Uint32 ip, unsigned char proto)
{
	struct iphdr *ip_hdr;
	static unsigned short ip_id = 32;	
	unsigned char dest_eth_addr[ETH_ALEN];	
    Uint32 i;
    
	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;
	
	i=htons(skb->len);
	ip_hdr->tot_len[0]=i&0x00ff;
	i=(i>>8);
	ip_hdr->tot_len[1]=i&0x00ff; 
	
	i=htons(ip_id++);
	ip_hdr->id[0]=i&0x00ff;
	i=(i>>8);
	ip_hdr->id[1]=i&0x00ff;
	ip_hdr->frag_off[0] = 0;
	ip_hdr->frag_off[1] = 0;
	ip_hdr->ttl = 128;
	ip_hdr->protocol = proto;
	
	i=htonl(local_ip);
	ip_hdr->saddr[0]=i&0x000000ff;
	i=(i>>8);
	ip_hdr->saddr[1]=i&0x000000ff;
	i=(i>>8);
	ip_hdr->saddr[2]=i&0x000000ff;
	i=(i>>8);
	ip_hdr->saddr[3]=i&0x000000ff;
	
	i=htonl(ip);
	ip_hdr->daddr[0]=i&0x000000ff;
	i=(i>>8);
	ip_hdr->daddr[1]=i&0x000000ff;
	i=(i>>8);
	ip_hdr->daddr[2]=i&0x000000ff;
	i=(i>>8);
	ip_hdr->daddr[3]=i&0x000000ff;
    
    ip_hdr->check[0]=0;
    ip_hdr->check[1]=0;
	i=ip_fast_csum(ip_hdr,ip_hdr->ihl*4);
	ip_hdr->check[0]=i&0x00ff;
	i=(i>>8);
	ip_hdr->check[1]=i&0x00ff;	
	
	return eth_send(skb, dest_eth_addr, ETH_P_IP);
}

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

Uint32 ip_get_source_ip(struct sk_buff *skb)
{
	struct iphdr *ip_hdr;
	Uint32 i;
	ip_hdr = (struct iphdr *)(skb->buf + ETH_HLEN);
	i=ip_hdr->saddr[3];
	i=(i<<8);
	i=i+ip_hdr->saddr[2];
	i=(i<<8);
	i=i+ip_hdr->saddr[1];
	i=(i<<8);
	i=i+ip_hdr->saddr[0];
	return ntohl(i);
}