Code flow
=========

[X] Command line processing (Command line option can override the place of the
    configuration file)
[X] Configuration file processing (Command line options override configuration
    global values like modules directory, log destination)
[ ] Create logger thread
    [ ] Start logging according to configuration
[ ] Load modules
    [ ] Load module file
    [ ] Run initialization function to...
        [ ] Register extensions
        [ ] Create special interfaces
        [ ] Register to hooks
[ ] Create interfaces
    [ ] Create listener thread and sockets
    [ ] Create stream processing threads
    [ ] Associate stream processing threads with sockets
    [ ] Assign extensions to stream processing threads
    [ ] Process extension configuration directives
    [ ] Start socket thread
        When new connection arrives
        [ ] Create peer object
        [ ] Associate with corresponding stream interface
[ ] Run main loop
    [ ] Socket thread
        [ ] New connections
	    [ ] Run "before-accept" hook
	    [ ] Create client object unless connection is dropped in
	        "before-accept"
	    [ ] Run "after-accept" hooks
	    [ ] Install "always-install" extensions on client
	    [ ] Wait for remote XML Stream to start
	    [ ] Assign client to correct interface
	[ ] Old connections
	    [ ] Run "layer-accept" hooks
	    [ ] Run "before-interface" hooks
	    [ ] Pass to assigned interface
	    [ ] Run "after-interface" hooks
    [ ] Logging thread
	[ ] Process received lines one by one. Errors first, info next, debug
	    last
    [ ] Interface threads
        [ ] Receive data from socket thread
	[ ] Run "before-process" hooks
	[ ] Process stream
	[ ] Run "after-process" hooks
	[ ] Run "before-send" hooks
	[ ] Send packet to destination if packet is finished
	[ ] Run "after-send" hooks

During the connection additional extensions can be installed on the client,
like the layer-tls module's TLS encryptions extension.

Authentication
==============

When a client requests authentication, client credentials get through the
authentication module(s) associated with the interface. This authentication
module must always check the jid via an user storage module, and if necessary,
it should get the password (or any other credentials like a X509 certificate's
Common Name field, or a Kerberos principal name) from this storage module,
either.