editcap - Edit and/or translate the format of capture files
-=head1 SYNOPSYS
+=head1 SYNOPSIS
B<editcap>
S<[ B<-c> E<lt>packets per fileE<gt> ]>
S<[ B<-C> E<lt>choplenE<gt> ]>
-S<[ B<-d> ]>
S<[ B<-E> E<lt>error probabilityE<gt> ]>
S<[ B<-F> E<lt>file formatE<gt> ]>
+S<[ B<-W> E<lt>file format optionE<gt>]>
+S<[ B<-H> E<lt>input hosts file<gt> ]>
S<[ B<-A> E<lt>start timeE<gt> ]>
S<[ B<-B> E<lt>stop timeE<gt> ]>
S<[ B<-h> ]>
+S<[ B<-i> E<lt>seconds per fileE<gt> ]>
S<[ B<-r> ]>
S<[ B<-s> E<lt>snaplenE<gt> ]>
S<[ B<-t> E<lt>time adjustmentE<gt> ]>
+S<[ B<-S> E<lt>strict time adjustmentE<gt> ]>
S<[ B<-T> E<lt>encapsulation typeE<gt> ]>
S<[ B<-v> ]>
I<infile>
I<outfile>
S<[ I<packet#>[-I<packet#>] ... ]>
+B<editcap>
+S< B<-d> > |
+S< B<-D> E<lt>dup windowE<gt> > |
+S< B<-w> E<lt>dup time windowE<gt> >
+S<[ B<-v> ]>
+I<infile>
+I<outfile>
+
=head1 DESCRIPTION
B<Editcap> is a program that reads some or all of the captured packets from the
By default, it reads all packets from the I<infile> and writes them to the
I<outfile> in libpcap file format.
-A list of packet numbers can be specified on the command line; ranges of
-packet numbers can be specified as I<start>-I<end>, referring to all packets
-from I<start> to I<end>.
-The selected packets with those numbers will I<not> be written to the
-capture file.
-If the B<-r> flag is specified, the whole packet selection is reversed;
-in that case I<only> the selected packets will be written to the capture file.
+An optional list of packet numbers can be specified on the command tail;
+individual packet numbers separated by whitespace and/or ranges of packet
+numbers can be specified as I<start>-I<end>, referring to all packets from
+I<start> to I<end>. By default the selected packets with those numbers will
+I<not> be written to the capture file. If the B<-r> flag is specified, the
+whole packet selection is reversed; in that case I<only> the selected packets
+will be written to the capture file.
+
+B<Editcap> can also be used to remove duplicate packets. Several different
+options (B<-d>, B<-D> and B<-w>) are used to control the packet window
+or relative time window to be used for duplicate comparison.
B<Editcap> is able to detect, read and write the same capture files that
are supported by B<Wireshark>.
B<Editcap> can write the file in several output formats. The B<-F>
flag can be used to specify the format in which to write the capture
-file, B<editcap -F> provides a list of the available output formats.
+file; B<editcap -F> provides a list of the available output formats.
=head1 OPTIONS
=item -c E<lt>packets per fileE<gt>
-Sets the maximum number of packets per output file. Each output file will
+Splits the packet output to different files based on uniform packet counts
+with a maximum of <packets per file> each. Each output file will
be created with a suffix -nnnnn, starting with 00000. If the specified
-number of packets are written to the output file, the next output file is
+number of packets is written to the output file, the next output file is
opened. The default is to use a single output file.
=item -C E<lt>choplenE<gt>
-Sets the chop length to use when writing the packet data.
-Each packet is chopped at the packet end by a few <choplen> bytes of data.
+Sets the chop length to use when writing the packet data. Each packet is
+chopped by a few <choplen> bytes of data. Positive values chop at the packet
+beginning while negative values chop at the packet end.
-This is useful in the rare case that the conversion between two file
-formats leaves some random bytes at the end of each packet.
+This is useful for chopping headers for decapsulation of an entire capture or
+in the rare case that the conversion between two file formats leaves some random
+bytes at the end of each packet.
=item -d
-Attempts to remove duplicate packets. The length and MD5 sum of the
-current packet are compared to the previous four packets. If a match
-is found, the packet is skipped.
+Attempts to remove duplicate packets. The length and MD5 hash of the
+current packet are compared to the previous four (4) packets. If a
+match is found, the current packet is skipped. This option is equivalent
+to using the option B<-D 5>.
+
+=item -D E<lt>dup windowE<gt>
+
+Attempts to remove duplicate packets. The length and MD5 hash of the
+current packet are compared to the previous <dup window> - 1 packets.
+If a match is found, the current packet is skipped.
+
+The use of the option B<-D 0> combined with the B<-v> option is useful
+in that each packet's Packet number, Len and MD5 Hash will be printed
+to standard out. This verbose output (specifically the MD5 hash strings)
+can be useful in scripts to identify duplicate packets across trace
+files.
+
+The <dup window> is specified as an integer value between 0 and 1000000 (inclusive).
+
+NOTE: Specifying large <dup window> values with large tracefiles can
+result in very long processing times for B<editcap>.
+
+=item -w E<lt>dup time windowE<gt>
+
+Attempts to remove duplicate packets. The current packet's arrival time
+is compared with up to 1000000 previous packets. If the packet's relative
+arrival time is I<less than or equal to> the <dup time window> of a previous packet
+and the packet length and MD5 hash of the current packet are the same then
+the packet to skipped. The duplicate comparison test stops when
+the current packet's relative arrival time is greater than <dup time window>.
+
+The <dup time window> is specified as I<seconds>[I<.fractional seconds>].
+
+The [.fractional seconds] component can be specified to nine (9) decimal
+places (billionths of a second) but most typical trace files have resolution
+to six (6) decimal places (millionths of a second).
+
+NOTE: Specifying large <dup time window> values with large tracefiles can
+result in very long processing times for B<editcap>.
+
+NOTE: The B<-w> option assumes that the packets are in chronological order.
+If the packets are NOT in chronological order then the B<-w> duplication
+removal option may not identify some duplicates.
=item -E E<lt>error probabilityE<gt>
-Sets the probabilty that bytes in the output file are randomly changed.
+Sets the probability that bytes in the output file are randomly changed.
B<Editcap> uses that probability (between 0.0 and 1.0 inclusive)
to apply errors to each data byte in the file. For instance, a
probability of 0.02 means that each byte has a 2% chance of having an error.
provides a list of the available output formats. The default
is the B<libpcap> format.
+=item -W E<lt>file format optionE<gt>
+
+Save extra information in the file if the format supports it. For
+example,
+
+ -F pcapng -W n
+
+will save host name resolution records along with captured packets.
+
+Future versions of Wireshark may automatically change the capture format to
+B<pcapng> as needed.
+
+The argument is a string that may contain the following letter:
+
+B<n> write network address resolution information (pcapng only)
+
+=item -H E<lt>input "hosts" fileE<gt>
+
+Read a list of address to host name mappings and include the result in
+the output file. Implies B<-W n>.
+
+The input file format is described at
+L<http://en.wikipedia.org/wiki/Hosts_%28file%29>.
+
=item -A E<lt>start timeE<gt>
Saves only the packets whose timestamp is on or after start time.
=item -B E<lt>stop timeE<gt>
-Saves only the packets whose timestamp is on or before stop time.
+Saves only the packets whose timestamp is before stop time.
The time is given in the following format YYYY-MM-DD HH:MM:SS
=item -h
Prints the version and options and exits.
+=item -i E<lt>seconds per fileE<gt>
+
+Splits the packet output to different files based on uniform time intervals
+using a maximum interval of <seconds per file> each. Each output file will
+be created with a suffix -nnnnn, starting with 00000. If packets for the specified
+time interval are written to the output file, the next output file is
+opened. The default is to use a single output file.
+
=item -r
Reverse the packet selection.
collected on different machines where the time difference between the
two machines is known or can be estimated.
+=item -S E<lt>strict time adjustmentE<gt>
+
+Time adjust selected packets to insure strict chronological order.
+
+The <strict time adjustment> value represents relative seconds
+specified as [-]I<seconds>[I<.fractional seconds>].
+
+As the capture file is processed each packet's absolute time is
+I<possibly> adjusted to be equal to or greater than the previous
+packet's absolute timestamp depending on the <strict time
+adjustment> value.
+
+If <strict time adjustment> value is 0 or greater (e.g. 0.000001)
+then B<only> packets with a timestamp less than the previous packet
+will adjusted. The adjusted timestamp value will be set to be
+equal to the timestamp value of the previous packet plus the value
+of the <strict time adjustment> value. A <strict time adjustment>
+value of 0 will adjust the minimum number of timestamp values
+necessary to insure that the resulting capture file is in
+strict chronological order.
+
+If <strict time adjustment> value is specified as a
+negative value, then the timestamp values of B<all>
+packets will be adjusted to be equal to the timestamp value
+of the previous packet plus the absolute value of the
+<lt>strict time adjustment<gt> value. A <strict time
+adjustment> value of -0 will result in all packets
+having the timestamp value of the first packet.
+
+This feature is useful when the trace file has an occasional
+packet with a negative delta time relative to the previous
+packet.
+
=item -T E<lt>encapsulation typeE<gt>
Sets the packet encapsulation type of the output capture file.
Causes B<editcap> to print verbose messages while it's working.
+Use of B<-v> with the de-duplication switches of B<-d>, B<-D> or B<-w>
+will cause all MD5 hashes to be printed whether the packet is skipped
+or not.
+
=back
=head1 EXAMPLES
To get all packets from number 1-500 (inclusive) use:
- editcap -r capture.pcap 500.pcap 1-500
+ editcap -r capture.pcap first500.pcap 1-500
or
- editcap capture.pcap 500.pcap 501-9999999
+ editcap capture.pcap first500.pcap 501-9999999
+
+To exclude packets 1, 5, 10 to 20 and 30 to 40 from the new file use:
+
+ editcap capture.pcap exclude.pcap 1 5 10-20 30-40
+
+To select just packets 1, 5, 10 to 20 and 30 to 40 for the new file use:
+
+ editcap -r capture.pcap select.pcap 1 5 10-20 30-40
+
+To remove duplicate packets seen within the prior four frames use:
+
+ editcap -d capture.pcap dedup.pcap
+
+To remove duplicate packets seen within the prior 100 frames use:
+
+ editcap -D 101 capture.pcap dedup.pcap
+
+To remove duplicate packets seen I<equal to or less than> 1/10th of a second:
+
+ editcap -w 0.1 capture.pcap dedup.pcap
+
+To display the MD5 hash for all of the packets (and NOT generate any
+real output file):
+
+ editcap -v -D 0 capture.pcap /dev/null
+
+or on Windows systems
+
+ editcap -v -D 0 capture.pcap NUL
+
+To advance the timestamps of each packet forward by 3.0827 seconds:
+
+ editcap -t 3.0827 capture.pcap adjusted.pcap
-To filter out packets 10 to 20 and 30 to 40 into a new file use:
+To insure all timestamps are in strict chronological order:
- editcap capture.pcap selection.pcap 10-20 30-40
+ editcap -S 0 capture.pcap adjusted.pcap
To introduce 5% random errors in a capture file use:
git.samba.org / obnox / wireshark / wip.git / blobdiff