Hello,

I am in the process of porting 802.11s to custom hardware running 2.6.39.
While tracing the he compart-wireless daily build of 2012_04_09 using 
Wireshark 1.7.1 I noticed that the decoding the A5 and A6 based on the 
Address Extention Mode is incorrect. The trace is an MP (192.168.11.47) pinging 
a wired node 
(192.168.11.100) through an MPP.


I am forwarding this to the open80211s group both as a heads up and to 
confirm that the values in the captured records for the Address 
Extension Mode subfield are correct. They seem to be by my reading of the 
specification but I wanted to make sure.


Cheers, John Prokopenko


----- Forwarded Message -----
From: JOHN PROKOPENKO <[email protected]>
To: Community support list for Wireshark <[email protected]> 
Sent: Monday, April 16, 2012 12:19:08 AM
Subject: Wireshark 1.7.1 802.11s Decoding Bug (Mesh Control Field)
 
Hello,

There seems to be a bug in Wireshark 1.7.1 decoding 802.11s data frames 
generated with compart-wireless daily build 2012_04_09.
Please let me know how best to log the bug.

Examing
 packets sent to/from nodes external to the mesh the address extension mode 
bits are being incorrectly decoded.

Refering to the official 802.11s specification: 
7.1.6.3 Mesh Control Field and Table 9-3
While
 section 7.1.6.3 Table 7-6g1 is ambigous the convention in 802.11-2007 
is that the table values stating (binary) are in "natural binary" (i.e. 
b1b0).

*** Referring to the attached capture file. ****

There are (at least) three cases:

When
 ToDS_FromDS field = 11 (binary) and Address Extension Mode subfield = 
0x02  (binary 10) there are two extra addresses (A5 and A6) contained in
 the Mesh
 Control Field.
Looking at record 10 of the attached AirPcap one can 
see that the addresses are in fact contained in the record but are not 
displayed (note: the address are the correct ones).

Similarly 
looking at record 1when  Address Extension Mode subfield = 0x00  (binary
 00) two addresses are incorrectly displayed (i.e. the following LLC 
fields are displayed).

Record 3 is another case from9.22.3 of the
 802.11s spec Also when Address Extension Mode subfield = 0x01 address 
A5 is not displayed (A5 is correctly part of the record 
(f4:6d:04:99:ae:bb).
See NOTE 3 as to why the 4th address is stored in the Mesh Control Field. 

Attachment: Mesh_Control_Bug_cap1.pcapng
Description: Binary data

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