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.

AUTHOR