[Telepathy] Link-Local 1-1 stream tubes XMPP protocol

[Guillaume Desmottes]

According to Sjoerd, current 1-1 stream tube XMPP protocol is wrong. We
should design and implement a new one so the next release of Salut would
have 1-1 stream tube support enabled.

The protocol implement in Gabble is documented on
http://people.collabora.co.uk/~cassidy/tubes.html#usecases-p2p


It doesn't really make sense to re-use it as there is no point to use SI
in Salut.

The current protocol implemented in Salut is:

dev2 offers a stream tube to dev1:

<iq type="set" from="dev2 at cass-lpt-2" to="dev1 at cass-lpt-2"
id="20250806682">
  <tube type="stream" service="x-example" id="927266064"
xmlns="http://telepathy.freedesktop.org/xmpp/tubes">
  <transport port="52116"/>
   <parameters>
     <parameter name="login" type="str">badger</parameter>
     <parameter name="a_int" type="int">69</parameter>
    </parameters>
  </tube>
</iq>

dev2 accepts the tube offer

<iq type="result" from="dev1 at cass-lpt-2" to="dev2 at cass-lpt-2"
id="20250806682"/>

Then dev2 connects to $IP:52116 for each tube connection, where $IP is
the address announced by dev1's avahi presence (Salut tries each address
until finding one working).

When one the peer wants to close the tube, he sends an IQ stanza which
has to be acked by the other peer.

<iq to=bla from=foo type='set'>
<close xmlns="http://telepathy.freedesktop.org/xmpp/tubes"
id='tube_id'/>
</iq>


	G.