[asterisk-dev] q931 decoding question

Klaus Darilion klaus.mailinglists at pernau.at
Mon Jan 14 05:11:54 CST 2008

Matthew Fredrickson schrieb:
> Klaus Darilion wrote:
          Ext: 0  User information layer 1: Unknown (24)
>> My questions: Why does it gets parsed? Why is it set to 24? I checked 
>> libpri source code but could not find the relevant code. Maybe someone 
>> can point to the corresponding code.
> This looks like a bug in the Q.931 dumping code.  After I looked into 
> it, I saw that an oversight was made in the bearer_capability_dump 
> routine that is assume a length that doesn't include the IE name and 
> length in the length passed to it.  The bug was not present in the 
> bearer_capability_transmit routine, but on the off chance there might be 
> something like this elsewhere, I saw something similar in the _receive 
> routine and fixed it as well.  The bug in the receive routine appears to 
> be benign because of the way we're using it in Asterisk.  Please update 
> to latest 1.2, 1.4, or trunk from svn to see if it is fixed now.

Ok. So how is it handled now if UL1 it is not present?

Do you know if there is a difference in Q.931 between missing octets and 
values set to zero? E.g. is there a difference between UL1 set to zero 
or a missing UL1 octet?

Btw - there is also a new patch on mantis for proper decoding:


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