From 07354a18c10dfb6de9f9cf83ff6d4248eee31fb5 Mon Sep 17 00:00:00 2001
From: Gerald Combs <gerald@wireshark.org>
Date: Wed, 2 Jun 2010 00:30:25 +0000
Subject: From Jim Young via bug 4331:

This patch adds a new '-S' option to editcap that will rewrite timestamps of
packets to insure that the new capture file is in strict chronological order.

This option's primary use case is to fixup the occasional timestamps that have
a negative delta time relative to previous packet.

This feature is related to (but does not depend on) capinfos enhancement
submitted in bug #4315 which helps identify tracefiles with "out-of-order"
packets.

svn path=/trunk/; revision=33042
---
 doc/editcap.pod | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

(limited to 'doc')

diff --git a/doc/editcap.pod b/doc/editcap.pod
index 5499154731..f2cb2f7e34 100644
--- a/doc/editcap.pod
+++ b/doc/editcap.pod
@@ -17,6 +17,7 @@ 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>
@@ -204,6 +205,39 @@ This feature is useful when synchronizing dumps
 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.
@@ -288,6 +322,14 @@ 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 insure all timestamps are in strict chronological order:
+
+    editcap -S 0 capture.pcap adjusted.pcap
+
 To introduce 5% random errors in a capture file use:
 
 =over 4
-- 
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