[OpenSIPStack] Interim Code for CALEA support

[<jo...@op...>]

Hi Everyone,

I have recently added a new trunk in OpenSBC called CALEA trunk (refer 
to SBCCALEATrunk.cxx).  What this is, is a separate trunk that handles 
processing of packets for lawful intercep as mandated in CALEA 
(Communications Assistance for Law Enforcement Act).  Take note that 
this code is in its infancy and is not complete yet.  As of the moment, 
only the capability to save sip packets to pcap format is in place (rtp 
packets to follow).   Slowly the CALEA trunk will evolve into a fully 
functional LEA collector.

To test, look for the new section in http admin name "CALEA Calls".  You 
will find a text box here name CALEA Filter.   This should contain a set 
of comma delimited SIP URIs that you want to intercept (wild cards 
accepted).  Example:  sip:1111*, sip:2222*

All calls beginning with 1111 and 2222 will be intercepted by the CALEA 
trunk.   The PCAP dump will be saved in $(OPENSBCDIR)/calea/pcap directory.

CAVEAT:  There is still a bug in PCAFile.cxx that wrongly computes the 
ip checksum of the packets.  This will show in ethereal.  This error is 
considered benign.