path: root/release/src/linux/linux/net/ipv4/netfilter/ipt_ipp2p.c

#if defined(MODVERSIONS)
#include <linux/modversions.h>
#endif
#include <linux/module.h>
#include <linux/version.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_ipp2p.h>
#include <net/tcp.h>
#include <net/udp.h>

#define get_u8(X,O)  (*(__u8 *)(X + O))
#define get_u16(X,O)  (*(__u16 *)(X + O))
#define get_u32(X,O)  (*(__u32 *)(X + O))

MODULE_AUTHOR("Eicke Friedrich/Klaus Degner <ipp2p@ipp2p.org>");
MODULE_DESCRIPTION("An extension to iptables to identify P2P traffic.");
MODULE_LICENSE("GPL");


/*Search for UDP eDonkey/eMule/Kad commands*/
int
udp_search_edk (unsigned char *haystack, int packet_len)
{
    unsigned char *t = haystack;
    t += 8;

	switch (t[0]) {
		case 0xe3: 
		{	/*edonkey*/
			switch (t[1]) 
			{
				/* client -> server status request */
				case 0x96: 
					if (packet_len == 14) return ((IPP2P_EDK * 100) + 50);
					break;
				/* server -> client status request */
				case 0x97: if (packet_len == 42) return ((IPP2P_EDK * 100) + 51);
					break;
						/* server description request */
						/* e3 2a ff f0 .. | size == 6 */
				case 0xa2: if ( (packet_len == 14) && ( get_u16(t,2) == __constant_htons(0xfff0) ) ) return ((IPP2P_EDK * 100) + 52);
					break;
						/* server description response */
						/* e3 a3 ff f0 ..  | size > 40 && size < 200 */
				//case 0xa3: return ((IPP2P_EDK * 100) + 53);
				//	break;
				case 0x9a: if (packet_len==26) return ((IPP2P_EDK * 100) + 54);
					break;

				case 0x92: if (packet_len==18) return ((IPP2P_EDK * 100) + 55);
					break;
			}
			break;
		}
		case 0xe4: 
		{
			switch (t[1]) 
			{
						/* e4 20 .. | size == 43 */
				case 0x20: if ((packet_len == 43) && (t[2] != 0x00) && (t[34] != 0x00)) return ((IPP2P_EDK * 100) + 60);
					break;
						/* e4 00 .. 00 | size == 35 ? */
				case 0x00: if ((packet_len == 35) && (t[26] == 0x00)) return ((IPP2P_EDK * 100) + 61);
					break;
						/* e4 10 .. 00 | size == 35 ? */
				case 0x10: if ((packet_len == 35) && (t[26] == 0x00)) return ((IPP2P_EDK * 100) + 62);
					break;
						/* e4 18 .. 00 | size == 35 ? */
				case 0x18: if ((packet_len == 35) && (t[26] == 0x00)) return ((IPP2P_EDK * 100) + 63);
					break;
						/* e4 52 .. | size = 44 */
				case 0x52: if (packet_len == 44 ) return ((IPP2P_EDK * 100) + 64);
					break;
						/* e4 58 .. | size == 6 */
				case 0x58: if (packet_len == 14 ) return ((IPP2P_EDK * 100) + 65);
					break;
						/* e4 59 .. | size == 2 */
				case 0x59: if (packet_len == 10 )return ((IPP2P_EDK * 100) + 66);
					break;
					/* e4 28 .. | packet_len == 52,77,102,127... */
				case 0x28: if (((packet_len-52) % 25) == 0) return ((IPP2P_EDK * 100) + 67);
					break;
					/* e4 50 xx xx | size == 4 */
				case 0x50: if (packet_len == 12) return ((IPP2P_EDK * 100) + 68);
					break;
					/* e4 40 xx xx | size == 48 */
				case 0x40: if (packet_len == 56) return ((IPP2P_EDK * 100) + 69);
					break;
			}
			break;
		}
	} /* end of switch (t[0]) */
    return 0;
}/*udp_search_edk*/


/*Search for UDP Gnutella commands*/
int
udp_search_gnu (unsigned char *haystack, int packet_len)
{
    unsigned char *t = haystack;
    t += 8;
    
    if (memcmp(t, "GND", 3) == 0) return ((IPP2P_GNU * 100) + 51);
    if (memcmp(t, "GNUTELLA ", 9) == 0) return ((IPP2P_GNU * 100) + 52);
    return 0;
}/*udp_search_gnu*/


/*Search for UDP KaZaA commands*/
int
udp_search_kazaa (unsigned char *haystack, int packet_len)
{
    unsigned char *t = haystack;
    
    if (t[packet_len-1] == 0x00){
	t += (packet_len - 6);
	if (memcmp(t, "KaZaA", 5) == 0) return (IPP2P_KAZAA * 100 +50);
    }
    
    return 0;
}/*udp_search_kazaa*/

/*Search for UDP DirectConnect commands*/
int
udp_search_directconnect (unsigned char *haystack, int packet_len)
{
    unsigned char *t = haystack;
    if ((*(t + 8) == 0x24) && (*(t + packet_len - 1) == 0x7c)) {
    	t+=8;
    	if (memcmp(t, "SR ", 3) == 0)	 		return ((IPP2P_DC * 100) + 60);
    	if (memcmp(t, "Ping ", 5) == 0)	 		return ((IPP2P_DC * 100) + 61);
    }
    return 0;
}/*udp_search_directconnect*/



/*Search for UDP BitTorrent commands*/
int
udp_search_bit (unsigned char *haystack, int packet_len)
{
	switch(packet_len)
	{
		case 24:
			/* ^ 00 00 04 17 27 10 19 80 */
			if ((ntohl(get_u32(haystack, 8)) == 0x00000417) && (ntohl(get_u32(haystack, 12)) == 0x27101980)) 
				return (IPP2P_BIT * 100 + 50);
			break;
		case 44:
			if (get_u32(haystack, 16) == __constant_htonl(0x00000400) && get_u32(haystack, 36) == __constant_htonl(0x00000104)) 
				return (IPP2P_BIT * 100 + 51);
			if (get_u32(haystack, 16) == __constant_htonl(0x00000400))
				return (IPP2P_BIT * 100 + 61);
			break;
		case 65:
			if (get_u32(haystack, 16) == __constant_htonl(0x00000404) && get_u32(haystack, 36) == __constant_htonl(0x00000104)) 
				return (IPP2P_BIT * 100 + 52);
			if (get_u32(haystack, 16) == __constant_htonl(0x00000404))
				return (IPP2P_BIT * 100 + 62);
			break;
		case 67:
			if (get_u32(haystack, 16) == __constant_htonl(0x00000406) && get_u32(haystack, 36) == __constant_htonl(0x00000104)) 
				return (IPP2P_BIT * 100 + 53);
			if (get_u32(haystack, 16) == __constant_htonl(0x00000406))
				return (IPP2P_BIT * 100 + 63);
			break;
		case 211:
			if (get_u32(haystack, 8) == __constant_htonl(0x00000405)) 
				return (IPP2P_BIT * 100 + 54);
			break;
		case 29:
			if ((get_u32(haystack, 8) == __constant_htonl(0x00000401))) 
				return (IPP2P_BIT * 100 + 55);
			break;
		case 52:
			if (get_u32(haystack,8)  == __constant_htonl(0x00000827) &&
			get_u32(haystack,12) == __constant_htonl(0x37502950))
				return (IPP2P_BIT * 100 + 80);
			break;
		default:
			/* this packet does not have a constant size */
			if (packet_len >= 40 && get_u32(haystack, 16) == __constant_htonl(0x00000402) && get_u32(haystack, 36) == __constant_htonl(0x00000104)) 
				return (IPP2P_BIT * 100 + 56);
			break;
	}
    
	/* some extra-bitcomet rules:
	* "d1:" [a|r] "d2:id20:"
	*/
	if (packet_len > 30 && get_u8(haystack, 8) == 'd' && get_u8(haystack, 9) == '1' && get_u8(haystack, 10) == ':' )
	{
		if (get_u8(haystack, 11) == 'a' || get_u8(haystack, 11) == 'r')
		{
			if (memcmp(haystack+12,"d2:id20:",8)==0)
				return (IPP2P_BIT * 100 + 57);
		}
	}
    
#if 0
	/* bitlord rules */
	/* packetlen must be bigger than 40 */
	/* first 4 bytes are zero */
	if (packet_len > 40 && get_u32(haystack, 8) == 0x00000000)
	{
		/* first rule: 00 00 00 00 01 00 00 xx xx xx xx 00 00 00 00*/
		if (get_u32(haystack, 12) == 0x00000000 && 
		    get_u32(haystack, 16) == 0x00010000 &&
		    get_u32(haystack, 24) == 0x00000000 )
			return (IPP2P_BIT * 100 + 71);
			
		/* 00 01 00 00 0d 00 00 xx xx xx xx 00 00 00 00*/
		if (get_u32(haystack, 12) == 0x00000001 && 
		    get_u32(haystack, 16) == 0x000d0000 &&
		    get_u32(haystack, 24) == 0x00000000 )
			return (IPP2P_BIT * 100 + 71);
		
		    
	}
#endif

    return 0;
}/*udp_search_bit*/



/*Search for Ares commands*/
//#define IPP2P_DEBUG_ARES
int
search_ares (const unsigned char *payload, const u16 plen)
//int search_ares (unsigned char *haystack, int packet_len, int head_len)
{
//	const unsigned char *t = haystack + head_len;
	
	/* all ares packets start with  */
	if (payload[1] == 0 && (plen - payload[0]) == 3)
	{
		switch (payload[2])
		{
			case 0x5a:
				/* ares connect */
				if ( plen == 6 && payload[5] == 0x05 ) return ((IPP2P_ARES * 100) + 1);
				break;
			case 0x09:
				/* ares search, min 3 chars --> 14 bytes
				 * lets define a search can be up to 30 chars --> max 34 bytes
				 */
				if ( plen >= 14 && plen <= 34 ) return ((IPP2P_ARES * 100) + 1);
				break;
#ifdef IPP2P_DEBUG_ARES
			default:
			printk(KERN_DEBUG "Unknown Ares command %x recognized, len: %u \n", (unsigned int) payload[2],plen);
#endif /* IPP2P_DEBUG_ARES */
		}
	}

#if 0	        
	/* found connect packet: 03 00 5a 04 03 05 */
	/* new version ares 1.8: 03 00 5a xx xx 05 */
    if ((plen) == 6){	/* possible connect command*/
	if ((payload[0] == 0x03) && (payload[1] == 0x00) && (payload[2] == 0x5a) && (payload[5] == 0x05))
	    return ((IPP2P_ARES * 100) + 1);
    }
    if ((plen) == 60){	/* possible download command*/
	if ((payload[59] == 0x0a) && (payload[58] == 0x0a)){
	    if (memcmp(t, "PUSH SHA1:", 10) == 0) /* found download command */
	    	return ((IPP2P_ARES * 100) + 2);
	}
    }
#endif

    return 0;
} /*search_ares*/

/*Search for SoulSeek commands*/
int
search_soul (const unsigned char *payload, const u16 plen)
{
//#define IPP2P_DEBUG_SOUL
    /* match: xx xx xx xx | xx = sizeof(payload) - 4 */
    if (get_u32(payload, 0) == (plen - 4)){
	const __u32 m=get_u32(payload, 4);
	/* match 00 yy yy 00, yy can be everything */
        if ( get_u8(payload, 4) == 0x00 && get_u8(payload, 7) == 0x00 )
	{
#ifdef IPP2P_DEBUG_SOUL
	printk(KERN_DEBUG "0: Soulseek command 0x%x recognized\n",get_u32(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 1);
	}
	
        /* next match: 01 yy 00 00 | yy can be everything */
        if ( get_u8(payload, 4) == 0x01 && get_u16(payload, 6) == 0x0000 )
	{
#ifdef IPP2P_DEBUG_SOUL
	printk(KERN_DEBUG "1: Soulseek command 0x%x recognized\n",get_u16(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 2);
	}
	
	/* other soulseek commandos are: 1-5,7,9,13-18,22,23,26,28,35-37,40-46,50,51,60,62-69,91,92,1001 */
	/* try to do this in an intelligent way */
	/* get all small commandos */
	switch(m)
	{
		case 7:
		case 9:
		case 22:
		case 23:
		case 26:
		case 28:
		case 50:
		case 51:
		case 60:
		case 91:
		case 92:
		case 1001:
#ifdef IPP2P_DEBUG_SOUL
		printk(KERN_DEBUG "2: Soulseek command 0x%x recognized\n",get_u16(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 3);
	}
	
	if (m > 0 && m < 6 ) 
	{
#ifdef IPP2P_DEBUG_SOUL
		printk(KERN_DEBUG "3: Soulseek command 0x%x recognized\n",get_u16(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 4);
	}
	if (m > 12 && m < 19 )
	{
#ifdef IPP2P_DEBUG_SOUL
		printk(KERN_DEBUG "4: Soulseek command 0x%x recognized\n",get_u16(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 5);
	}

	if (m > 34 && m < 38 )
	{
#ifdef IPP2P_DEBUG_SOUL
		printk(KERN_DEBUG "5: Soulseek command 0x%x recognized\n",get_u16(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 6);
	}

	if (m > 39 && m < 47 )
	{
#ifdef IPP2P_DEBUG_SOUL
		printk(KERN_DEBUG "6: Soulseek command 0x%x recognized\n",get_u16(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 7);
	}

	if (m > 61 && m < 70 ) 
	{
#ifdef IPP2P_DEBUG_SOUL
		printk(KERN_DEBUG "7: Soulseek command 0x%x recognized\n",get_u16(payload, 4));
#endif /* IPP2P_DEBUG_SOUL */
		return ((IPP2P_SOUL * 100) + 8);
	}

#ifdef IPP2P_DEBUG_SOUL
	printk(KERN_DEBUG "unknown SOULSEEK command: 0x%x, first 16 bit: 0x%x, first 8 bit: 0x%x ,soulseek ???\n",get_u32(payload, 4),get_u16(payload, 4) >> 16,get_u8(payload, 4) >> 24);
#endif /* IPP2P_DEBUG_SOUL */
    }
	
	/* match 14 00 00 00 01 yy 00 00 00 STRING(YY) 01 00 00 00 00 46|50 00 00 00 00 */
	/* without size at the beginning !!! */
	if ( get_u32(payload, 0) == 0x14 && get_u8(payload, 4) == 0x01 )
	{
		__u32 y=get_u32(payload, 5);
		/* we need 19 chars + string */
		if ( (y + 19) <= (plen) )
		{
			const unsigned char *w=payload+9+y;
			if (get_u32(w, 0) == 0x01 && ( get_u16(w, 4) == 0x4600 || get_u16(w, 4) == 0x5000) && get_u32(w, 6) == 0x00);
#ifdef IPP2P_DEBUG_SOUL
	    		printk(KERN_DEBUG "Soulssek special client command recognized\n");
#endif /* IPP2P_DEBUG_SOUL */
	    		return ((IPP2P_SOUL * 100) + 9);
		}
	}
    return 0;
}


/*Search for WinMX commands*/
int
search_winmx (const unsigned char *payload, const u16 plen)
{
//#define IPP2P_DEBUG_WINMX
    if (((plen) == 4) && (memcmp(payload, "SEND", 4) == 0))  return ((IPP2P_WINMX * 100) + 1);
    if (((plen) == 3) && (memcmp(payload, "GET", 3) == 0))  return ((IPP2P_WINMX * 100) + 2);
    //if (packet_len < (head_len + 10)) return 0;
    if (plen < 10) return 0;
    
    if ((memcmp(payload, "SEND", 4) == 0) || (memcmp(payload, "GET", 3) == 0)){
        u16 c=4;
        const u16 end=plen-2;
        u8 count=0;
        while (c < end)
        {
        	if (payload[c]== 0x20 && payload[c+1] == 0x22)
        	{
        		c++;
        		count++;
        		if (count>=2) return ((IPP2P_WINMX * 100) + 3);
        	}
        	c++;
        }
    }
    
    if ( plen == 149 && payload[0] == '8' )
    {
#ifdef IPP2P_DEBUG_WINMX
    	printk(KERN_INFO "maybe WinMX\n");
#endif
    	if (get_u32(payload,17) == 0 && get_u32(payload,21) == 0 && get_u32(payload,25) == 0 &&
//    	    get_u32(payload,33) == __constant_htonl(0x71182b1a) && get_u32(payload,37) == __constant_htonl(0x05050000) &&
//    	    get_u32(payload,133) == __constant_htonl(0x31097edf) && get_u32(payload,145) == __constant_htonl(0xdcb8f792))
    	    get_u16(payload,39) == 0 && get_u16(payload,135) == __constant_htons(0x7edf) && get_u16(payload,147) == __constant_htons(0xf792))
    	    
    	{
#ifdef IPP2P_DEBUG_WINMX
    		printk(KERN_INFO "got WinMX\n");
#endif
    		return ((IPP2P_WINMX * 100) + 4);
    	}
    }
    return 0;
} /*search_winmx*/


/*Search for appleJuice commands*/
int
search_apple (const unsigned char *payload, const u16 plen)
{
    if ( (plen > 7) && (payload[6] == 0x0d) && (payload[7] == 0x0a) && (memcmp(payload, "ajprot", 6) == 0))  return (IPP2P_APPLE * 100);
    
    return 0;
}


/*Search for BitTorrent commands*/
int
search_bittorrent (const unsigned char *payload, const u16 plen)
{
    if (plen > 20)
    {
	/* test for match 0x13+"BitTorrent protocol" */
	if (payload[0] == 0x13) 
	{
		if (memcmp(payload+1, "BitTorrent protocol", 19) == 0) return (IPP2P_BIT * 100);
	}
	
	/* get tracker commandos, all starts with GET /
	* then it can follow: scrape| announce
	* and then ?hash_info=
	*/
	if (memcmp(payload,"GET /",5) == 0)
	{
		/* message scrape */
		if ( memcmp(payload+5,"scrape?info_hash=",17)==0 ) return (IPP2P_BIT * 100 + 1);
		/* message announce */
		if ( memcmp(payload+5,"announce?info_hash=",19)==0 ) return (IPP2P_BIT * 100 + 2);
	}
    } 
    else 
    {
    	/* bitcomet encryptes the first packet, so we have to detect another 
    	 * one later in the flow */
    	 /* first try failed, too many missdetections */
    	//if ( size == 5 && get_u32(t,0) == __constant_htonl(1) && t[4] < 3) return (IPP2P_BIT * 100 + 3);
    	
    	/* second try: block request packets */
    	if ( plen == 17 && get_u32(payload,0) == __constant_htonl(0x0d) && payload[4] == 0x06 && get_u32(payload,13) == __constant_htonl(0x4000) ) return (IPP2P_BIT * 100 + 3);
    }

    return 0;
}



/*check for Kazaa get command*/
int
search_kazaa (const unsigned char *payload, const u16 plen)

{
    if ((payload[plen-2] == 0x0d) && (payload[plen-1] == 0x0a) && memcmp(payload, "GET /.hash=", 11) == 0)
	return (IPP2P_DATA_KAZAA * 100);

    return 0;
}


/*check for gnutella get command*/
int
search_gnu (const unsigned char *payload, const u16 plen)
{
    if ((payload[plen-2] == 0x0d) && (payload[plen-1] == 0x0a))
    {
	if (memcmp(payload, "GET /get/", 9) == 0)	return ((IPP2P_DATA_GNU * 100) + 1);
	if (memcmp(payload, "GET /uri-res/", 13) == 0) return ((IPP2P_DATA_GNU * 100) + 2); 
    }
    return 0;
}


/*check for gnutella get commands and other typical data*/
int
search_all_gnu (const unsigned char *payload, const u16 plen)
{
    
    if ((payload[plen-2] == 0x0d) && (payload[plen-1] == 0x0a))
    {
	
	if (memcmp(payload, "GNUTELLA CONNECT/", 17) == 0) return ((IPP2P_GNU * 100) + 1);
	if (memcmp(payload, "GNUTELLA/", 9) == 0) return ((IPP2P_GNU * 100) + 2);    
    
    
	if ((memcmp(payload, "GET /get/", 9) == 0) || (memcmp(payload, "GET /uri-res/", 13) == 0))
	{        
		u16 c=8;
		const u16 end=plen-22;
		while (c < end) {
			if ( payload[c] == 0x0a && payload[c+1] == 0x0d && ((memcmp(&payload[c+2], "X-Gnutella-", 11) == 0) || (memcmp(&payload[c+2], "X-Queue:", 8) == 0))) 
				return ((IPP2P_GNU * 100) + 3);
			c++;
		}
	}
    }
    return 0;
}


/*check for KaZaA download commands and other typical data*/
int
search_all_kazaa (const unsigned char *payload, const u16 plen)
{
    if ((payload[plen-2] == 0x0d) && (payload[plen-1] == 0x0a))
    {

	if (memcmp(payload, "GIVE ", 5) == 0) return ((IPP2P_KAZAA * 100) + 1);
    
    	if (memcmp(payload, "GET /", 5) == 0) {
		u16 c = 8;
		const u16 end=plen-22;
		while (c < end) {
			if ( payload[c] == 0x0a && payload[c+1] == 0x0d && ((memcmp(&payload[c+2], "X-Kazaa-Username: ", 18) == 0) || (memcmp(&payload[c+2], "User-Agent: PeerEnabler/", 24) == 0)))
				return ((IPP2P_KAZAA * 100) + 2);
			c++;
		}
	}
    }
    return 0;
}

/*fast check for edonkey file segment transfer command*/
int
search_edk (const unsigned char *payload, const u16 plen)
{
    if (payload[0] != 0xe3) 
	return 0;
    else {
	if (payload[5] == 0x47) 
	    return (IPP2P_DATA_EDK * 100);
	else 	
	    return 0;
    }
}



/*intensive but slower search for some edonkey packets including size-check*/
int
search_all_edk (const unsigned char *payload, const u16 plen)
{
    if (payload[0] != 0xe3) 
	return 0;
    else {
	//t += head_len;	
	const u16 cmd = get_u16(payload, 1);
	if (cmd == (plen - 5)) {
	    switch (payload[5]) {
		case 0x01: return ((IPP2P_EDK * 100) + 1);	/*Client: hello or Server:hello*/
		case 0x4c: return ((IPP2P_EDK * 100) + 9);	/*Client: Hello-Answer*/
	    }
	}
	return 0;
     }
}


/*fast check for Direct Connect send command*/
int
search_dc (const unsigned char *payload, const u16 plen)
{

    if (payload[0] != 0x24 ) 
	return 0;
    else {
	if (memcmp(&payload[1], "Send|", 5) == 0)
	    return (IPP2P_DATA_DC * 100);
	else
	    return 0;
    }	

}


/*intensive but slower check for all direct connect packets*/
int
search_all_dc (const unsigned char *payload, const u16 plen)
{
//    unsigned char *t = haystack;

    if (payload[0] == 0x24 && payload[plen-1] == 0x7c) 
    {
    	const unsigned char *t=&payload[1];
    		/* Client-Hub-Protocol */
	if (memcmp(t, "Lock ", 5) == 0)	 		return ((IPP2P_DC * 100) + 1);
	/* Client-Client-Protocol, some are already recognized by client-hub (like lock) */
	if (memcmp(t, "MyNick ", 7) == 0)	 	return ((IPP2P_DC * 100) + 38); 
    }
    return 0;
}

/*check for mute*/
int
search_mute (const unsigned char *payload, const u16 plen)
{
	if ( plen == 209 || plen == 345 || plen == 473 || plen == 609 || plen == 1121 )
	{
		//printk(KERN_DEBUG "size hit: %u",size);
		if (memcmp(payload,"PublicKey: ",11) == 0 )
		{ 
			return ((IPP2P_MUTE * 100) + 0);
			
/*			if (memcmp(t+size-14,"\x0aEndPublicKey\x0a",14) == 0)
			{
				printk(KERN_DEBUG "end pubic key hit: %u",size);
				
			}*/
		}
	}
	return 0;
}


/* check for xdcc */
int
search_xdcc (const unsigned char *payload, const u16 plen)
{
	/* search in small packets only */
	if (plen > 20 && plen < 200 && payload[plen-1] == 0x0a && payload[plen-2] == 0x0d && memcmp(payload,"PRIVMSG ",8) == 0)
	{
		
		u16 x=10;
		const u16 end=plen - 13;
		
		/* is seems to be a irc private massage, chedck for xdcc command */
		while (x < end)
		{
			if (payload[x] == ':')
			{
				if ( memcmp(&payload[x+1],"xdcc send #",11) == 0 )
					return ((IPP2P_XDCC * 100) + 0);
			}
			x++;
		}
	}
	return 0;
}

/* search for waste */
int search_waste(const unsigned char *payload, const u16 plen)
{
	if ( plen >= 8 && memcmp(payload,"GET.sha1:",9) == 0)
		return ((IPP2P_WASTE * 100) + 0);

	return 0;
}


static struct {
    int command;
    __u8 short_hand;			/*for fucntions included in short hands*/
    int packet_len;
    int (*function_name) (const unsigned char *, const u16);
} matchlist[] = {
    {IPP2P_EDK,SHORT_HAND_IPP2P,20, &search_all_edk},
//    {IPP2P_DATA_KAZAA,SHORT_HAND_DATA,200, &search_kazaa},
//    {IPP2P_DATA_EDK,SHORT_HAND_DATA,60, &search_edk},
//    {IPP2P_DATA_DC,SHORT_HAND_DATA,26, &search_dc},
    {IPP2P_DC,SHORT_HAND_IPP2P,5, search_all_dc},
//    {IPP2P_DATA_GNU,SHORT_HAND_DATA,40, &search_gnu},
    {IPP2P_GNU,SHORT_HAND_IPP2P,5, &search_all_gnu},
    {IPP2P_KAZAA,SHORT_HAND_IPP2P,5, &search_all_kazaa},
    {IPP2P_BIT,SHORT_HAND_IPP2P,20, &search_bittorrent},
    {IPP2P_APPLE,SHORT_HAND_IPP2P,5, &search_apple},
    {IPP2P_SOUL,SHORT_HAND_IPP2P,5, &search_soul},
    {IPP2P_WINMX,SHORT_HAND_IPP2P,2, &search_winmx},
    {IPP2P_ARES,SHORT_HAND_IPP2P,5, &search_ares},
    {IPP2P_MUTE,SHORT_HAND_NONE,200, &search_mute},
    {IPP2P_WASTE,SHORT_HAND_NONE,5, &search_waste},
    {IPP2P_XDCC,SHORT_HAND_NONE,5, &search_xdcc},
    {0,0,0,NULL}
};


static struct {
    int command;
    __u8 short_hand;			/*for fucntions included in short hands*/
    int packet_len;
    int (*function_name) (unsigned char *, int);
} udp_list[] = {
    {IPP2P_KAZAA,SHORT_HAND_IPP2P,14, &udp_search_kazaa},
    {IPP2P_BIT,SHORT_HAND_IPP2P,23, &udp_search_bit},
    {IPP2P_GNU,SHORT_HAND_IPP2P,11, &udp_search_gnu},
    {IPP2P_EDK,SHORT_HAND_IPP2P,9, &udp_search_edk},
    {IPP2P_DC,SHORT_HAND_IPP2P,12, &udp_search_directconnect},    
    {0,0,0,NULL}
};


static int
match(const struct sk_buff *skb,
      const struct net_device *in,
      const struct net_device *out,
      const void *matchinfo,
      int offset,

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
      const void *hdr,
      u_int16_t datalen,
#endif

      int *hotdrop)
{
    const struct ipt_p2p_info *info = matchinfo;
    unsigned char  *haystack;
    struct iphdr *ip = skb->nh.iph;
    int p2p_result = 0, i = 0;
//    int head_len;
    int hlen = ntohs(ip->tot_len)-(ip->ihl*4);	/*hlen = packet-data length*/

    /*must not be a fragment*/
    if (offset) {
	if (info->debug) printk("IPP2P.match: offset found %i \n",offset);
	return 0;
    }
    
    /*make sure that skb is linear*/
    if(skb_is_nonlinear(skb)){
	if (info->debug) printk("IPP2P.match: nonlinear skb found\n");
	return 0;
    }


    haystack=(char *)ip+(ip->ihl*4);		/*haystack = packet data*/

    switch (ip->protocol){
	case IPPROTO_TCP:		/*what to do with a TCP packet*/
	{
	    struct tcphdr *tcph = (void *) ip + ip->ihl * 4;
	    
	    if (tcph->fin) return 0;  /*if FIN bit is set bail out*/
	    if (tcph->syn) return 0;  /*if SYN bit is set bail out*/
	    if (tcph->rst) return 0;  /*if RST bit is set bail out*/
	    
	    haystack += tcph->doff * 4; /*get TCP-Header-Size*/
	    hlen -= tcph->doff * 4;
	    while (matchlist[i].command) {
		if ((((info->cmd & matchlist[i].command) == matchlist[i].command) ||
		    ((info->cmd & matchlist[i].short_hand) == matchlist[i].short_hand)) &&
		    (hlen > matchlist[i].packet_len)) {
			    p2p_result = matchlist[i].function_name(haystack, hlen);
			    if (p2p_result) 
			    {
				if (info->debug) printk("IPP2P.debug:TCP-match: %i from: %u.%u.%u.%u:%i to: %u.%u.%u.%u:%i Length: %i\n", 
				    p2p_result, NIPQUAD(ip->saddr),ntohs(tcph->source), NIPQUAD(ip->daddr),ntohs(tcph->dest),hlen);
				return p2p_result;
    			    }
    		}
	    i++;
	    }
	    return p2p_result;
	}
	
	case IPPROTO_UDP:		/*what to do with an UDP packet*/
	{
	    struct udphdr *udph = (void *) ip + ip->ihl * 4;
	    
	    while (udp_list[i].command){
		if ((((info->cmd & udp_list[i].command) == udp_list[i].command) ||
		    ((info->cmd & udp_list[i].short_hand) == udp_list[i].short_hand)) &&
		    (hlen > udp_list[i].packet_len)) {
			    p2p_result = udp_list[i].function_name(haystack, hlen);
			    if (p2p_result){
				if (info->debug) printk("IPP2P.debug:UDP-match: %i from: %u.%u.%u.%u:%i to: %u.%u.%u.%u:%i Length: %i\n", 
				    p2p_result, NIPQUAD(ip->saddr),ntohs(udph->source), NIPQUAD(ip->daddr),ntohs(udph->dest),hlen);
				return p2p_result;
			    }
		}
	    i++;
	    }			
	    return p2p_result;
	}
    
	default: return 0;
    }
}



static int
checkentry(const char *tablename,
            const struct ipt_ip *ip,
	    void *matchinfo,
	    unsigned int matchsize,
	    unsigned int hook_mask)
{
        /* Must specify -p tcp */
/*    if (ip->proto != IPPROTO_TCP || (ip->invflags & IPT_INV_PROTO)) {
 *	printk("ipp2p: Only works on TCP packets, use -p tcp\n");
 *	return 0;
 *    }*/
    return 1;
}
									    



static struct ipt_match ipp2p_match = { 
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
	{ NULL, NULL }, 
	"ipp2p", 
	&match, 
	&checkentry, 
	NULL, 
	THIS_MODULE
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
	.name		= "ipp2p",
	.match		= &match,
	.checkentry	= &checkentry,
	.me		= THIS_MODULE,
#endif
};


static int __init init(void)
{
    printk(KERN_INFO "IPP2P v%s loading\n", IPP2P_VERSION);
    return ipt_register_match(&ipp2p_match);
}
	
static void __exit fini(void)
{
    ipt_unregister_match(&ipp2p_match);
    printk(KERN_INFO "IPP2P v%s unloaded\n", IPP2P_VERSION);    
}
	
module_init(init);
module_exit(fini);