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char * payload;
            int count=1;
		udp = (struct sniff_udp*)(packet + SIZE_ETHERNET + SIZE_UDP);
		size_payload = ntohs(ip->ip_len) - (size_ip + SIZE_UDP);
		
		/* define computer udp payload (segment) offset */
		payload = (u_char *)(packet + SIZE_ETHERNET + size_ip + SIZE_UDP);

	char search_reg[]="REGISTER"; /* search for register method in payload */
	char search_sip[]="Via: SIP"; /* variable to identify sip packet */
	

	if (strstr(payload, search_sip)) 
	{ 
		/* compute udp payload (segment) size */
		if (size_payload > ntohs(udp->uh_ulen))
		{
			size_payload = ntohs(udp->uh_ulen);
		}
		printf("\n SIP Packet number %d:\n", count);
		count++;
		int reg_method = 0; /* variable to identify sip method*/
		if (strstr(payload, search_reg)) 
		{ 
			reg_method = 1; /* sip method is REGISTER*/
			if ( reg_method==1)
				printf("\n REGISTER METHOD \n"); 
		}
	
		if (size_payload > 0) 
		{		  	
				char * tch;		/* Parsing pointer for strtok function */
				char * from;		/* "From" pointer */
				char * contact;		/* "Contact" pointer */
				char * user;		/* "User" pointer */
				char * callid;		/* "Call-ID" pointer */ 
				tch = strtok (payload,"<>;\n\"");
				while (tch != NULL)
				{         
					if (strncmp(tch, "From",4)==0) /* Comparation of first 4 chars to "From" and if so collect it*/
					{
						tch = strtok (NULL, "<>;\n\"");
						from = tch;                 
						printf ("\n	SIP From: %s \n", from); 
					}   
					if (strncmp(tch, "Contact",7)==0) /* Comparation of first 7 chars to "Contact" and if so collect it*/
					{
						tch = strtok (NULL, "<>;\n\"");
						contact = tch;                 
						printf ("	SIP Contact: %s \n", contact); 
					} 
					if (strncmp(tch, "Authorization",13)==0) /* Comparation of first 13 chars to "Authorization" and if so collect it*/
					{
						tch = strtok (NULL, "<>;\n\"");
						user = tch;                 
						printf ("	SIP User: %s \n", user); 
					}   
					if (strncmp(tch, "Call-ID",7)==0)  /* Comparation of first 7 chars to "Call-ID" and if so collect it*/
					{       
						callid = tch;                 
						printf (" %s \n", callid); 
					}                           
                                      tch = strtok (NULL, "<>;\n\"");
				}