Bug 875

Summary:	"frame includes FCS" flag should be set in Radiotap frame header
Product:	ns-3	Reporter:	Dean Armstrong <deanarm>
Component:	helpers	Assignee:	Dean Armstrong <deanarm>
Status:	RESOLVED FIXED
Severity:	normal	CC:	nicola, ns-bugs
Priority:	P5	Keywords:	bug
Version:	ns-3-dev
Hardware:	All
OS:	All
URL:	http://codereview.appspot.com/904042

Description Dean Armstrong 2010-04-13 14:25:46 UTC

The Wi-Fi PCAP tracing with Radiotap data link format captures the entire MPDU including FCS, so the "frame includes FCS" flag in the Radiotap header for each frame should be set so that tools like Wireshark won't try to decode this field as MPDU payload.

The current undesired behaviour can be seen by taking a PCAP/Radiotap trace including (for example) a Beacon frame, and then loading this into Wireshark. Looking at the "Tagged Parameters" section you'll see that Wireshark has decoded the last four octets (i.e., the FCS) as two zero length SSID information elements.

Comment 1 Dean Armstrong 2010-04-13 14:28:13 UTC

A proposed patch for this is available at:

http://codereview.appspot.com/904042

Please comment.

Comment 2 Dean Armstrong 2010-04-13 14:53:14 UTC

The wifi-wired-bridging test reference traces will need updating when this bug is fixed (this appears to be the only test that uses Radiotap tracing). The updated traces are also available under the 'afore-mentioned codereview issue.

Comment 3 Dean Armstrong 2010-05-10 09:02:32 UTC

I would like to deal with this bug in the near future. Is the bug, and code I previously proposed as Issue 904042 on codereview contentious, or can I go ahead and fix it?

Comment 4 Nicola Baldo 2010-05-14 13:07:00 UTC


(In reply to comment #3)
> I would like to deal with this bug in the near future. Is the bug, and code I
> previously proposed as Issue 904042 on codereview contentious, or can I go
> ahead and fix it?

Hi Dean, sorry for the late reply. The bug is confirmed and the patch is ok, so please go ahead and commit. Thanks for the good work!

Comment 5 Dean Armstrong 2010-05-14 16:27:54 UTC

Fixed by:

changeset 6299:56ac87d0f2f9 on ns-3-dev, and
changeset 114:0a54dfc12e7f on ns-3-dev-ref-traces