NAME Net::TcpDumpLog - Read tcpdump/libpcap network packet logs. Perl implementation (not an interface). SYNOPSIS use Net::TcpDumpLog; $log = Net::TcpDumpLog->new(); $log->read("/tmp/out01"); @Indexes = $log->indexes; foreach $index (@Indexes) { ($length_orig,$length_incl,$drops,$secs,$msecs) = $log->header($index); $data = $log->data($index); # your code here } DESCRIPTION This module can read the data and headers from tcpdump logs (these use the libpcap log format). METHODS new () Constructor, return a TcpDumpLog object. If your OS uses 64-bit timestamps, supply an argument of "64". read (FILENAME) Read the tcpdump file indicated into memory. indexes () Return an array of index numbers for the packets loaded from the tcpdump file. The indexes start at 0. maxindex () Return the number of the last index. More memory efficient than indexes(). Add 1 to get the packet count. The indexes start at 0. header (INDEX) Takes an integer index number and returns the packet header. This is: Length of original packet, Length actually included in the tcpdump log, Number of bytes dropped in this packet, Packet arrival time as seconds since Jan 1st 1970, Microseconds data (INDEX) Takes an integer index number and returns the raw packet data. (This is usually Ethernet/IP/TCP data). version () Returns a string containing the libpcap log version, major and minor number - which is expected to be "2.4". linktype () Returns a strings containing the numeric linktype. zoneoffset () Returns the zoneoffset for the packet log. accuracy () Returns a the accuracy of the packet log. dumplength () Returns the length of the packet log. INSTALLATION perl Makefile.PL make make test make install DEPENDENCIES ExtUtils::MakeMaker EXAMPLES Once you can read the raw packet data, the next step is read through the protocol stack. An Ethernet/802.3 example is, ($ether_dest,$ether_src,$ether_type,$ether_data) = unpack('H12H12H4a*',$data); Keep an eye on CPAN for Ethernet, IP and TCP modules. LIMITATIONS This reads tcpdump/libpcap version 2.4 logs (the most common). There could be new versions in the future, at which point this module will need updating. BUGS If this module is not reading your logs correctly, try creating the tcpdump object in 64-bit timestamp mode, eg "$log = Net::TcpDumpLog->new(64);". If the problem persists, try printing out the log version using version() and checking it is "2.4". TODO Future versions should include the ability to write as well as read tcpdump logs. Also a memory efficient technique to process very large tcpdump logs (where the log size is greater than available virtual memory). SEE ALSO http://www.tcpdump.org COPYRIGHT Copyright (c) 2003 Brendan Gregg. All rights reserved. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself AUTHORS Brendan Gregg [Sydney, Australia]