ip_input.c

一个基于linux的TCP/IP协议栈的实现

/* ip_input.c
 * [e-mail]
 * 2006-09-19
 */

#include "myip.h"
#include "log.h"
#include "dummy_ipv4.h"
#include "protocol.h"
#include "af_inet.h"

#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>

struct net_protocol *myinet_protos[MAX_INET_PROTOS];

static inline int myip_local_deliver_finish(struct sk_buff *skb)
{

	int protocol = IPPROTO_DUMMY;
	int hash = protocol & (MAX_INET_PROTOS - 1);
	struct net_protocol *ipprot;

	PR_DEBUG( "myip_local_deliver_finish!\n" );	
	rcu_read_lock();

	if( (ipprot = rcu_dereference(myinet_protos[hash])) != NULL ){
		ipprot->handler( skb );
	}else{
		dev_put( skb->dev );
		kfree(skb );
	} 

	rcu_read_unlock();
	return 0;
}

int myip_local_deliver(struct sk_buff *skb)
{
/*
	if( skb->nh.iph->frag_off & htons(IP_MF|IP_OFFSET) ){
		skb = ip_defrag( skb, IP_DEFRAG_LOCAL_DELIVER );
		if( !skb )
			return 0;
	}
*/
	return NF_HOOK( MY_PF_INET, NF_IP_LOCAL_IN, skb, skb->dev, 
					NULL, myip_local_deliver_finish);
}

static inline int mydst_input(struct sk_buff *skb)
{
	PR_DEBUG( "mydst_input!\n" );
	return myip_local_deliver( skb );
}

static inline int myip_rcv_finish(struct sk_buff *skb)
{
	PR_DEBUG( "myip_rcv_finish!\n");
	return mydst_input( skb );	
}

int myip_rcv(struct sk_buff *skb, struct net_device *dev, 
				struct packet_type *pt, struct net_device *orig_dev)
{
	PR_DEBUG( "myip_rcv!\n" );
	dev_put( dev );
	return NF_HOOK( MY_PF_INET, NF_IP_PRE_ROUTING, skb, dev, NULL, myip_rcv_finish );

}

EXPORT_SYMBOL_GPL( myip_rcv );
EXPORT_SYMBOL_GPL( myinet_protos );