=head1 NAME

Net::RawIP::libpcap - An interface to B<libpcap> in Net::RawIP(3pm)

=head1 DESCRIPTION

 Function    The input parameters           The output parameters

 open_live   a network                      Return value is a pcap_t*
             device(eth0,ppp0,...);         If retval less than zero
             a snap length;                 then $err filled with
             a promisc - boolean;           an error string.
	     a timeout in sec;               
	     $err is an undef scalar;

 open_offline   a filename which is filled  Return value is pcap_t*
                with a raw output of dump;  If retval less than zero
                $err is an unfef scalar;    then $err filled with
		                            an error string.

 dump_open  pcap_t*;                        Return value is a FILE*
            $err; 

 lookupdev  $err;			    Return value is a name
                                            of first device which is
					    found by libpcap

 lookupnet  a network device;               a netnumber;
            a netnumer is undef;            a netmask;    
	    a netmask is undef;             If retval less than zero
	    $err is undef;                  then $err filled with
				            an error string.
  
 dispatch   a scalar with pcap_t*;          No output parameters.
            number of packets for proce-
	    ssing;
	    reference to the perl call-
	    back,this callback will be
	    called with 3 parameters:
	    $_[0] is fourth parameter
	    from dispatch,
	    $_[1] is a scalar with struc-
	    ture pcap_pkthdr for a current
	    packet,
	    $_[2] is a scalar with a current
	    packet;
	    fourth parameter could be
	    an array or a hash reference
	    or a pointer (FILE*) returned
	    by dump_open,it can be unre-
	    ferenced in the perl call-
	    back or be used as a perl
	    filehandle in that callback.
  
 loop 	    As for dispatch.                As for dispatch.
  
 dump       As for a perl callback          No output. 
            but $_[0] must be a pointer 
	    (FILE*) only.

 compile    a scalar with pcap_t*;        a scalar with bpf_program. 
            a bpf_program is undef;       If retval is less than zero
	    a scalar with filter string;  then there was a problem with
	    a boolean value (optimize or  filter grammar.
	    not);
	      a scalar with netmask;

 setfilter  a scalar with pcap_t*;        If retval is less than zero
	    a scalar with bpf_program     then there was a problem while
	    returned by compile.          settting filter.
  
 next     a scalar with pcap_t*;          A scalar with next packet;
          a scalar with with struc-       a scalar with with structure
	  ture pcap_pkthdr for a current  pcap_pkthdr also will be modi
	  packet,originally is undef.     filed for an every packet and 
		                          it can be accessed but for read
					  only.
					      
 datalink  a scalar with pcap_t*;         Retval is the link  layer type,
                                          e.g. DLT_EN10MB.
	 						        		 
 snapshot  a scalar with pcap_t*;         Retval is the snapshot length 
                                          specified when open_live was 
					  called.		 	 	 
    
 is_swapped  a scalar with pcap_t*;       returns true if the current 
                                          savefile uses a different 
					  byte order than the current 
					  system.                   
  
 major_version  a scalar with pcap_t*;    returns the major number 
                                          of the version of the pcap 
					  used to write the savefile.
  
 minor_version  a scalar with pcap_t*;    returns the minor number of the
                                          version of the pcap used to 
					  write the savefile.

 file       a scalar with pcap_t*;        returns the name of the 
                                          savefile.
   											      					      
 stats      a scalar with pcap_t*;        If retval 0 then a scalar 
            a scalar with structure       with structure pcap_stat will
	    pcap_stat,originally undef    be filled with the 
                                          packet statistics.

 fileno    a scalar with pcap_t*;        returns  the  file descriptor 
                                         number of the savefile.
					 A core perl function is 
					 available as CORE::fileno.
					      
 geterr   a scalar with pcap_t*;         returns  the  error  text 
                                         pertaining to the last pcap 
				         library error.
					      
 perror   a scalar with pcap_t*;         prints the text of the last  
          a scalar with prefix;          pcap  library error on stderr, 
		                         prefixed by prefix.
  
 close    a scalar with pcap_t*;         closes the files associated with 
                                         pcap_t* and deallocates 
					 resources.
	                                 A core perl function is 
					 available as CORE::close.
											    
 dump_close  a scalar with pcap_t*;      closes the savefile.    					      

=head1 AUTHOR

Sergey Kolychev <ksv@al.lg.ua>

=head1 SEE ALSO

Net::RawIP(3pm),pcap(3).

=cut