/*             Sat Mar  8 00:05:40 2003
 *
 *					Bertera Pietro 
 *		e-mail: p.bertera@valtellinux.it dr.iggy@iol.it
 *
 *					compile with:
 * gcc -Wall -DMODULE -D__KERNEL__ -DDEBUG -c NetSniff.c -I/usr/src/linux/include
 *
 *					run with:
 * insmod NetSniff.o
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Library General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
 


#ifndef __KERNEL__
#define __KERNEL__
#endif
#ifndef MODULE
#define MODULE
#endif

#include <asm/uaccess.h>
#include <asm/byteorder.h> 


#include <linux/module.h>

#include <linux/sched.h>
#include <linux/kernel.h> 
#include <linux/slab.h>	   
#include <linux/errno.h>  
#include <linux/types.h>  
#include <linux/interrupt.h> 

#include <linux/netdevice.h>   
#include <linux/etherdevice.h> 
#include <linux/ip.h>          
#include <linux/tcp.h>         
#include <linux/udp.h>		   
#include <linux/skbuff.h>


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

#include <linux/config.h>
#include <linux/in.h>
#include <linux/socket.h>

MODULE_LICENSE("GPL");


unsigned int in_hook(unsigned int hooknum,
                             struct sk_buff **skb_p,
                             const struct net_device *in,
                             const struct net_device *out,
                             int (*okfn)(struct sk_buff *))
{
    int retval = NF_ACCEPT;
	struct 	sk_buff *skb = (*skb_p); 				
	struct 	iphdr  *iph = NULL;  				
    struct 	tcphdr *tcph = NULL; 				
	struct 	udphdr *udph = NULL;				

	__u32   saddr;						
	__u32 	daddr; 					
	__u8	protocol_type; 		
	__u16  	dport = 0;								
	__u16	sport = 0;		
	
	iph = skb->nh.iph; 
	
	saddr = iph->saddr;
	daddr = iph->daddr;
	
	protocol_type=iph->protocol;
	
	if(protocol_type == IPPROTO_TCP){
		
		if((skb->h.th) != NULL){
			tcph = (struct tcphdr*)((__u32 *)iph+iph->ihl);
			
			if((tcph->dest)){
				dport = tcph->dest;
			}else{
				printk("TCP D port NULL!!\n");
			}
			
			if((tcph->source)){
				sport = tcph->source;
			}else{
				printk("TCP S port NULL!!\n");
			}
		}else{
			printk("TCP HEADER NULL!!\n");
		}
		printk("INPUT: TCP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
	if(protocol_type == IPPROTO_UDP){
		printk("UDP!!\n");
		
		if((skb->h.uh) != NULL){
			udph = (struct udphdr*)((__u32 *)iph+iph->ihl);
				
			if((udph->dest)){
				dport = udph->dest;
			}else{
				printk("UDP D port NULL!!\n");
			}
			
			if((udph->source)){
				sport = udph->source;
			}else{
				printk("UDP S port NULL!!\n");
			}
		}else{
			printk("UDP HEADER NULL!!\n");
		}
		printk("INPUT: UDP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
    return retval; 
}
unsigned int out_hook(unsigned int hooknum,
                             struct sk_buff **skb_p,
                             const struct net_device *in,
                             const struct net_device *out,
                             int (*okfn)(struct sk_buff *))
{
    int retval = NF_ACCEPT;
	struct 	sk_buff *skb = (*skb_p); 				
	struct 	iphdr  *iph = NULL;  				
    struct 	tcphdr *tcph = NULL; 				
	struct 	udphdr *udph = NULL;				

	__u32   saddr;						
	__u32 	daddr; 					
	__u8	protocol_type; 		
	__u16  	dport = 0;								
	__u16	sport = 0;		
	
	iph = skb->nh.iph; 
	
	saddr = iph->saddr;
	daddr = iph->daddr;
	
	protocol_type=iph->protocol;
	
	if(protocol_type == IPPROTO_TCP){
		
		if((skb->h.th) != NULL){
			tcph = (struct tcphdr*)((__u32 *)iph+iph->ihl);
			
			if((tcph->dest)){
				dport = tcph->dest;
			}else{
				printk("TCP D port NULL!!\n");
			}
			
			if((tcph->source)){
				sport = tcph->source;
			}else{
				printk("TCP S port NULL!!\n");
			}
		}else{
			printk("TCP HEADER NULL!!\n");
		}
		printk("OUTPUT: TCP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
	if(protocol_type == IPPROTO_UDP){
		printk("UDP!!\n");
		
		if((skb->h.uh) != NULL){
			udph = (struct udphdr*)((__u32 *)iph+iph->ihl);
				
			if((udph->dest)){
				dport = udph->dest;
			}else{
				printk("UDP D port NULL!!\n");
			}
			
			if((udph->source)){
				sport = udph->source;
			}else{
				printk("UDP S port NULL!!\n");
			}
		}else{
			printk("UDP HEADER NULL!!\n");
		}
		printk("OUTPUT: UDP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
    return retval; 
}
unsigned int fw_hook(unsigned int hooknum,
                             struct sk_buff **skb_p,
                             const struct net_device *in,
                             const struct net_device *out,
                             int (*okfn)(struct sk_buff *))
{
    int retval = NF_ACCEPT;
	struct 	sk_buff *skb = (*skb_p); 				
	struct 	iphdr  *iph = NULL;  				
    struct 	tcphdr *tcph = NULL; 				
	struct 	udphdr *udph = NULL;				

	__u32   saddr;						
	__u32 	daddr; 					
	__u8	protocol_type; 		
	__u16  	dport = 0;								
	__u16	sport = 0;		
	
	iph = skb->nh.iph; 
	
	saddr = iph->saddr;
	daddr = iph->daddr;
	
	protocol_type=iph->protocol;
	
	if(protocol_type == IPPROTO_TCP){
		
		if((skb->h.th) != NULL){
			tcph = (struct tcphdr*)((__u32 *)iph+iph->ihl);
			
			if((tcph->dest)){
				dport = tcph->dest;
			}else{
				printk("TCP D port NULL!!\n");
			}
			
			if((tcph->source)){
				sport = tcph->source;
			}else{
				printk("TCP S port NULL!!\n");
			}
		}else{
			printk("TCP HEADER NULL!!\n");
		}
		printk("FORWARD: TCP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
	if(protocol_type == IPPROTO_UDP){
		printk("UDP!!\n");
		
		if((skb->h.uh) != NULL){
			udph = (struct udphdr*)((__u32 *)iph+iph->ihl);
				
			if((udph->dest)){
				dport = udph->dest;
			}else{
				printk("UDP D port NULL!!\n");
			}
			
			if((udph->source)){
				sport = udph->source;
			}else{
				printk("UDP S port NULL!!\n");
			}
		}else{
			printk("UDP HEADER NULL!!\n");
		}
		printk("FORWARD: UDP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
    return retval; 
}
unsigned int pre_hook(unsigned int hooknum,
                             struct sk_buff **skb_p,
                             const struct net_device *in,
                             const struct net_device *out,
                             int (*okfn)(struct sk_buff *))
{
    int retval = NF_ACCEPT;
	struct 	sk_buff *skb = (*skb_p); 				
	struct 	iphdr  *iph = NULL;  				
    struct 	tcphdr *tcph = NULL; 				
	struct 	udphdr *udph = NULL;				

	__u32   saddr;						
	__u32 	daddr; 					
	__u8	protocol_type; 		
	__u16  	dport = 0;								
	__u16	sport = 0;		
	
	iph = skb->nh.iph; 
	
	saddr = iph->saddr;
	daddr = iph->daddr;
	
	protocol_type=iph->protocol;
	
	if(protocol_type == IPPROTO_TCP){
		
		if((skb->h.th) != NULL){
			tcph = (struct tcphdr*)((__u32 *)iph+iph->ihl);
			
			if((tcph->dest)){
				dport = tcph->dest;
			}else{
				printk("TCP D port NULL!!\n");
			}
			
			if((tcph->source)){
				sport = tcph->source;
			}else{
				printk("TCP S port NULL!!\n");
			}
		}else{
			printk("TCP HEADER NULL!!\n");
		}
		printk("PREROUTING: TCP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
	if(protocol_type == IPPROTO_UDP){
		printk("UDP!!\n");
		
		if((skb->h.uh) != NULL){
			udph = (struct udphdr*)((__u32 *)iph+iph->ihl);
				
			if((udph->dest)){
				dport = udph->dest;
			}else{
				printk("UDP D port NULL!!\n");
			}
			
			if((udph->source)){
				sport = udph->source;
			}else{
				printk("UDP S port NULL!!\n");
			}
		}else{
			printk("UDP HEADER NULL!!\n");
		}
		printk("PREROUTING: UDP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
    return retval; 
}
unsigned int post_hook(unsigned int hooknum,
                             struct sk_buff **skb_p,
                             const struct net_device *in,
                             const struct net_device *out,
                             int (*okfn)(struct sk_buff *))
{
    int retval = NF_ACCEPT;
	struct 	sk_buff *skb = (*skb_p); 				
	struct 	iphdr  *iph = NULL;  				
    struct 	tcphdr *tcph = NULL; 				
	struct 	udphdr *udph = NULL;				

	__u32   saddr;						
	__u32 	daddr; 					
	__u8	protocol_type; 		
	__u16  	dport = 0;								
	__u16	sport = 0;		
	
	iph = skb->nh.iph; 
	
	saddr = iph->saddr;
	daddr = iph->daddr;
	
	protocol_type=iph->protocol;
	
	if(protocol_type == IPPROTO_TCP){
		
		if((skb->h.th) != NULL){
			tcph = (struct tcphdr*)((__u32 *)iph+iph->ihl);
			
			if((tcph->dest)){
				dport = tcph->dest;
			}else{
				printk("TCP D port NULL!!\n");
			}
			
			if((tcph->source)){
				sport = tcph->source;
			}else{
				printk("TCP S port NULL!!\n");
			}
		}else{
			printk("TCP HEADER NULL!!\n");
		}
		printk("POSTROUTING: TCP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
	if(protocol_type == IPPROTO_UDP){
		printk("UDP!!\n");
		
		if((skb->h.uh) != NULL){
			udph = (struct udphdr*)((__u32 *)iph+iph->ihl);
				
			if((udph->dest)){
				dport = udph->dest;
			}else{
				printk("UDP D port NULL!!\n");
			}
			
			if((udph->source)){
				sport = udph->source;
			}else{
				printk("UDP S port NULL!!\n");
			}
		}else{
			printk("UDP HEADER NULL!!\n");
		}
		printk("POSTROUTING: UDP S: %d.%d.%d.%d:%d  D: %d.%d.%d.%d:%d\n",NIPQUAD(saddr),sport,NIPQUAD(daddr),dport);
	}
	
    return retval; 
}

struct nf_hook_ops in_hook_ops = {  
   hook :       in_hook,
   pf :         PF_INET,
   hooknum :    NF_IP_LOCAL_IN,
};

struct nf_hook_ops out_hook_ops = { 
   hook :       out_hook,   
   pf :         PF_INET,
   hooknum :    NF_IP_LOCAL_OUT,
};

struct nf_hook_ops fw_hook_ops = {   
   hook :       fw_hook,   
   pf :         PF_INET,
   hooknum :    NF_IP_FORWARD,
};

struct nf_hook_ops pre_hook_ops = {   
   hook :       pre_hook,   
   pf :         PF_INET,
   hooknum :    NF_IP_PRE_ROUTING,
};

struct nf_hook_ops post_hook_ops = {   
   hook :       post_hook,   
   pf :         PF_INET,
   hooknum :    NF_IP_POST_ROUTING,
};

static int init_status_flag;
#define IN_HOOK_REGISTERED		0x02
#define OUT_HOOK_REGISTERED		0x04
#define FW_HOOK_REGISTERED		0x06
#define PRE_HOOK_REGISTERED		0x08
#define POST_HOOK_REGISTERED	0x20

void cleanup_module(void)
{

    if (init_status_flag&IN_HOOK_REGISTERED)   
       nf_unregister_hook(&in_hook_ops);

    if (init_status_flag&OUT_HOOK_REGISTERED)   
       nf_unregister_hook(&out_hook_ops);

	if (init_status_flag&FW_HOOK_REGISTERED)  
       nf_unregister_hook(&fw_hook_ops);
	
	if (init_status_flag&PRE_HOOK_REGISTERED)  
       nf_unregister_hook(&pre_hook_ops);
	
	if (init_status_flag&POST_HOOK_REGISTERED)  
       nf_unregister_hook(&post_hook_ops);
}

int init_module(void)
{
   int result;

       result = nf_register_hook(&in_hook_ops);
       if (result < 0) {
           printk(KERN_ERR "can't register netfilter hook");
           cleanup_module();
           return result;
       }
       init_status_flag |= IN_HOOK_REGISTERED;

       result = nf_register_hook(&out_hook_ops);
       if (result < 0) {
           printk(KERN_ERR "can't register netfilter hook");
           cleanup_module();
           return result;
       }
       init_status_flag |= OUT_HOOK_REGISTERED;

       result = nf_register_hook(&fw_hook_ops);
       if (result < 0) {
           printk(KERN_ERR "can't register netfilter hook");
           cleanup_module();
           return result;
       }
       init_status_flag |= FW_HOOK_REGISTERED;
	   
	   result = nf_register_hook(&pre_hook_ops);
       if (result < 0) {
           printk(KERN_ERR "can't register netfilter hook");
           cleanup_module();
           return result;
       }
       init_status_flag |= PRE_HOOK_REGISTERED;
	   
	   result = nf_register_hook(&post_hook_ops);
       if (result < 0) {
           printk(KERN_ERR "can't register netfilter hook");
           cleanup_module();
           return result;
       }
       init_status_flag |= POST_HOOK_REGISTERED;
	   printk("Netfilter Sniff run! stop with: #rmmod NetSnif \n");
	   
    return 0; 
}