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568 lines
29 KiB
XML
568 lines
29 KiB
XML
<?xml version='1.0' encoding='UTF-8'?>
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<!DOCTYPE xep SYSTEM 'xep.dtd' [
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<!ENTITY % ents SYSTEM 'xep.ent'>
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%ents;
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]>
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<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
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<xep>
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<header>
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<title>Jingle SOCKS5 Bytestreams Transport Method</title>
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<abstract>This specification defines a Jingle transport method that results in sending data via the SOCKS5 Bytestreams (S5B) protocol defined in XEP-0065. Essentially this transport method reuses XEP-0065 semantics for sending the data and defines native Jingle methods for starting and ending an S5B session.</abstract>
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&LEGALNOTICE;
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<number>0260</number>
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<status>Experimental</status>
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<type>Standards Track</type>
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<sig>Standards</sig>
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<dependencies>
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<spec>XMPP Core</spec>
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<spec>XEP-0030</spec>
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<spec>XEP-0065</spec>
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</dependencies>
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<supersedes/>
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<supersededby/>
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<shortname>jingle-s5b</shortname>
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<discuss>jingle</discuss>
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&stpeter;
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&dmeyer;
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&infiniti;
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<author>
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<firstname>Klaus</firstname>
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<surname>Hartke</surname>
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<email>klaus.hartke@googlemail.com</email>
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<jid>nx@jabber.org</jid>
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</author>
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<revision>
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<version>0.3</version>
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<date>2009-07-14</date>
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<initials>dm/kh/psa/jk</initials>
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<remark><p>Major update to make Jingle S5B inherit more features from ICE and ICE-TCP. Added priorities and candidate identifiers. Renamed streamhost element to candidate element. Updated candidate selection to use priorities, and it is now required for both clients to send a candidate-used or candidate-error notification. Defined type attribute to differentiate between various kinds of candidates. More clearly described how S5B negotiation is completed, including an activated notification from responder to initiator when the candidate used is a proxy. Noted reuse of fast-mode methodology from S5B optimization specification. Because of incompatibilities with the previous version, changed the namespace to urn:xmpp:jingle:transports:s5b:1.</p></remark>
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</revision>
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<revision>
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<version>0.2</version>
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<date>2009-03-09</date>
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<initials>psa</initials>
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<remark><p>Minor changes to track modifications to XEP-0166; updated security considerations for consistency with other transport methods; added section on service discovery.</p></remark>
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</revision>
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<revision>
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<version>0.1</version>
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<date>2009-02-19</date>
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<initials>psa</initials>
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<remark><p>Initial published version.</p></remark>
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</revision>
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<revision>
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<version>0.0.3</version>
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<date>2009-02-18</date>
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<initials>psa</initials>
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<remark><p>Clarified order of events to be consistent with raw-udp and ice-udp.</p></remark>
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</revision>
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<revision>
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<version>0.0.2</version>
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<date>2009-02-11</date>
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<initials>dm/jk</initials>
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<remark><p>Specified that the responder can send <streamhost/> candidates, consistent with the earlier S5B optimization extension; this change required the introduction of streamhost-used and streamhost-error. Also added text to encourage the use of NAT-assisting protocols.</p></remark>
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</revision>
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<revision>
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<version>0.0.1</version>
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<date>2009-02-10</date>
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<initials>psa</initials>
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<remark><p>Rough draft.</p></remark>
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</revision>
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</header>
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<section1 topic='Introduction' anchor='intro'>
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<p>&xep0166; defines a framework for negotiating and managing data sessions over XMPP. In order to provide a flexible framework, the base Jingle specification defines neither data transport methods nor application formats, leaving that up to separate specifications. The current document defines a transport method for establishing and managing data exchanges between XMPP entities using the existing SOCKS5 Bytestreams (S5B) protocol specified in &xep0065;. This "jingle-s5b" method results in a streaming transport method suitable for use in Jingle application types where packet loss cannot be tolerated (e.g., file transfer). Jingle-S5B reuses the protocol flow from <cite>XEP-0065</cite> for the communication with a SOCKS5 streamhost; the communication between two clients to negotiate the possible candidates differs from <cite>XEP-0065</cite> and share similarities with &xep0176;</p>
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</section1>
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<section1 topic='Protocol' anchor='protocol'>
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<para>The basic flow is as follows.</para>
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<code><![CDATA[
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Romeo Juliet
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| |
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| session-initiate |
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| (with S5B candidates) |
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|--------------------------------->|
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| ack |
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|<---------------------------------|
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| session-accept |
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| (with S5B candidates) |
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|<---------------------------------|
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| ack |
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|--------------------------------->|
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| candidate-used transport-info |
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|<---------------------------------|
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| ack |
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|--------------------------------->|
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| candidate-used transport-info |
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|--------------------------------->|
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| ack |
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|<---------------------------------|
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| S5B "SESSION" |
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|<================================>|
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| session-terminate |
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|<---------------------------------|
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| ack |
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|--------------------------------->|
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| |
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]]></code>
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<p>This flow is illustrated in the following examples (to simplify the presentation these use a "stub" application instead of a real application type).</p>
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<section2 topic='Exchanging Candidates' anchor='exchange'>
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<p>First the initiator sends a Jingle session-initiate request that contains one or more transport candidates which are a mixture of <cite>XEP-0065</cite> streamhosts and ICE candidates used in <cite>XEP-0176</cite>.</p>
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<p>It is RECOMMENDED that a client will offer as many <candidate/> elements as possible with itself as the host (i.e., non-proxy candidates). This includes opening the TCP port on all available interfaces the user wants to use (e.g. maybe not an expensive UMTS link), both the IPv4 and IPv6 addresses of that interface (if available), and using an assisting NAT protocol if possible. If the client knows it is behind a NAT and the router announces UPnP IGD or NAT-PMP support, the client SHOULD map the open port to the external interface of the router and include the public IP address and port information in the <candidate/> offers. To increase the chance of success without using a proxy, this specification allows the responder to also send offers, effectively equivalent to the "fast-mode" for SOCKS5 Bytestreams as previously described at <<link url='http://delta.affinix.com/specs/stream.html'>http://delta.affinix.com/specs/stream.html</link>>.</p>
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<example caption="Initiator sends session-initiate (stub)"><![CDATA[
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<iq from='romeo@montague.lit/orchard'
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id='xn28s7gk'
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to='juliet@capulet.lit/balcony'
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type='set'>
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<jingle xmlns='urn:xmpp:jingle:1'>
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action='session-initiate'
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initiator='romeo@montague.lit/orchard'
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sid='a73sjjvkla37jfea'>
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<content creator='initiator' name='stub'>
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<description xmlns='urn:xmpp:jingle:apps:stub:0'/>
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<transport xmlns='urn:xmpp:jingle:transports:s5b:1'
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sid='vj3hs98y'
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mode='tcp'>
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<candidate cid='hft54dqy'
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host='192.168.4.1'
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jid='romeo@montague.lit/orchard'
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port='5086'
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priority='8257636'
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type='direct'/>
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<candidate cid='hutr46fe'
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host='24.24.24.1'
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jid='romeo@montague.lit/orchard'
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port='5087'
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priority='8258636'
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type='direct'/>
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</transport>
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</content>
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</jingle>
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</iq>
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]]></example>
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<p>The responder immediately acknowledges receipt.</p>
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<example caption="Responder acknowledges session-initiate"><![CDATA[
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<iq from='juliet@capulet.lit/balcony'
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id='xn28s7gk'
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to='romeo@montague.lit/orchard'
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type='result'/>
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]]></example>
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<p>Depending on the application type, a user agent controlled by a human user might need to wait for the user to affirm a desire to proceed with the session before continuing. When the user agent has received such affirmation (or if the user agent can automatically proceed for any reason, e.g. because no human intervention is expected or because a human user has configured the user agent to automatically accept sessions with a given entity), it returns a Jingle session-accept message. This message MUST contain a &TRANSPORT; element qualified by the 'urn:xmpp:jingle:transports:s5b:1' namespace, which SHOULD in turn contain one <candidate/> element for each SOCKS5 Bytestreams candidate generated by or known to the responder, but MAY instead be empty if the responder does not wish to offer any candidates or wishes to send each candidate as the payload of a transport-info message.</p>
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<p>Note: If the responder sends candidates, the chances of a successful connection are increased. For example, the initiator might be behind a NAT or might have no access to a proxy, whereas the responder might have a public IP address, might know about a proxy, or might have NAT penetration support like NAT-PMP in the router. (Whereas this "fast-mode" was a special extension previously, it is the default in Jingle.)</p>
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<p>In the following example, Juliet's client opens one port. The provided <candidates/> are the (private) IPv4 address of the interface, a (public) IPv6 address, and the public IPv4 address created by mapping the private IP address/port using NAT-PMP.</p>
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<example caption="Responder sends session-accept with candidates"><![CDATA[
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<iq from='juliet@capulet.lit/balcony'
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id='hwd987h'
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to='romeo@montague.lit/orchard'
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type='set'>
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<jingle xmlns='urn:xmpp:jingle:1'>
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action='session-accept'
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initiator='romeo@montague.lit/orchard'
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sid='a73sjjvkla37jfea'>
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<content creator='initiator' name='stub'>
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<description xmlns='urn:xmpp:jingle:apps:stub:0'/>
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<transport xmlns='urn:xmpp:jingle:transports:s5b:1'
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sid='vj3hs98y'
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mode='tcp'>
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<candidate cid='ht567dq'
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host='192.169.1.10'
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jid='juliet@capulet.lit/balcony'
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port='6539'
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priority='8257636'
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type='direct'/>
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<candidate cid='hr65dqyd'
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host='134.102.201.180'
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jid='juliet@capulet.lit/balcony'
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port='16453'
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priority='7929856'
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type='direct'/>
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<candidate cid='grt654q2'
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host='2001:638:708:30c9:219:d1ff:fea4:a17d'
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jid='juliet@capulet.lit/balcony'
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port='6539'
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priority='8257606'
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type='direct'/>
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</transport>
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</content>
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</jingle>
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</iq>
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]]></example>
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<p>The initiator acknowledges receipt and tries to connect to the offered candidates.</p>
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<example caption="Initiator acknowledges session-accept"><![CDATA[
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<iq from='romeo@montague.lit/orchard'
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id='hwd987h'
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to='juliet@capulet.lit/balcony'
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type='result'/>
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]]></example>
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<p>A client SHOULD check the offered candidates in order of their priority, starting with the highest value. How the priority is calculated depends on the actual available interfaces. It is RECOMMENDED to use the following formula:</p>
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<example caption="Priority Calculation"><![CDATA[
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priority = (2^16)*(type preference) + (local preference)
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]]></example>
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<p>The type preference is an integer value between 0 and 127. The following types and their suggested preference values are defined here:</p>
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<table caption='Defined Types'>
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<tr>
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<th>Type</th>
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<th>Description</th>
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<th>Preference Value</th>
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</tr>
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<tr>
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<td>direct</td>
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<td>Direct connection using the given interface</td>
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<td>126</td>
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</tr>
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<tr>
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<td>assisted</td>
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<td>Direct connection using NAT assisting technologies like NAT-PMP or UPnP-IGD</td>
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<td>120</td>
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</tr>
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<tr>
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<td>tunnel</td>
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<td>Tunnel protocols such as Teredo</td>
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<td>110</td>
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</tr>
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<tr>
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<td>proxy</td>
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<td>SOCKS5 Relay</td>
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<td>10</td>
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</tr>
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</table>
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<p>The local preference is used to rate different candidates of the same type, e.g. a DSL link might be preferred over a VPN connection. The value of the local preference SHOULD be between 0 and 65535. The proposed values are only guidelines. If a client wants to increase or decrease the value of a specific candidate it is free to do so. For instance, a client might have an expensive UMTS link as last resort and might rate this link lower than all SOCKS5 relays.</p>
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</section2>
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<section2 topic='Connecting to Candidates' anchor='connect'>
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<p>After receiving its peer's candidates, a client start to connect to them in order of the priority. The protocol is described in <cite>XEP-0065</cite> in detail. Once one client has successfully created a connection, it sends the <candidate-used/> element to the peer inside a transport-info Jingle message. If a client receives a candidate-used information it SHOULD continue trying to connect to candidates of its peer if it has not tried all candidates with a higher priority than the one successfully used by the peer.</p>
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<example caption="Initiator sends candidate-used in Jingle transport-info"><![CDATA[
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<iq from='romeo@montague.lit/orchard'
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id='hjdi8'
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to='juliet@capulet.lit/balcony'
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type='set'>
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<jingle xmlns='urn:xmpp:jingle:1'>
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action='transport-info'
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initiator='romeo@montague.lit/orchard'
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sid='a73sjjvkla37jfea'>
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<content creator='initiator' name='stub'>
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<transport xmlns='urn:xmpp:jingle:transports:s5b:1'
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sid='vj3hs98y'>
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<candidate-used cid='hr65dqyd'/>
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</transport>
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</content>
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</jingle>
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</iq>
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]]></example>
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<p>The peer immediately acknowledges receipt.</p>
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<example caption="Responder acknowledges candidate-used message"><![CDATA[
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<iq from='juliet@capulet.lit/balcony'
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id='hjdi8'
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to='romeo@montague.lit/orchard'
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type='result'/>
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]]></example>
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<p>If a client is unable to connect to <em>any</em> candidate sent by its peer, or if it stopped trying to connect because its peer sent a candidate-used notification with a priority higher than its remaining candidate(s), it sends a candidate-error Jingle transport-info message (this is equivalent to the IQ-error with code="500" from the "fast-mode" extension).</p>
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<example caption="Responder sends candidate-error in Jingle transport-info"><![CDATA[
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<iq from='juliet@capulet.lit/balcony'
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id='gft65ewd'
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to='romeo@montague.lit/orchard'
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type='set'>
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<jingle xmlns='urn:xmpp:jingle:1'>
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action='transport-info'
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initiator='romeo@montague.lit/orchard'
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sid='a73sjjvkla37jfea'>
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<content creator='initiator' name='stub'>
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<transport xmlns='urn:xmpp:jingle:transports:s5b:1'
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sid='vj3hs98y'>
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<candidate-error/>
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</transport>
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</content>
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</jingle>
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</iq>
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]]></example>
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<p>The peer immediately acknowledges receipt.</p>
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<example caption="Responder acknowledges candidate-error message"><![CDATA[
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<iq from='romeo@montague.lit/orchard'
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id='gft65ewd'
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to='juliet@capulet.lit/balcony'
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type='result'/>
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]]></example>
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</section2>
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<section2 topic='Completing the Negotiation' anchor='complete'>
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<p>The transport negotiation is completed in one of the following ways:</p>
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<ol start='1'>
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<li>If both parties send a candidate-error notification then the SOCKS5 negotiation has failed and the parties need to fall back to some other transport method, typically IBB; see the <link url='#fallback'>Fallback to IBB</link> section of this document for details.</li>
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<li>If one of the parties sends a candidate-error notification and the other party sends a candidate-used notification, then the candidate-used shall be considered the nominated candidate.</li>
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<li>If both parties send a candidate-used notification but the candidates have a different priority, then the candidate with the lower priority shall be considered the nominated candidate.</li>
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<li>If both parties send a candidate-used notification with candidates having the same priority, then the candidate chosen by the initiator shall be considered the nominated candidate (consistent with the rules in <cite>XEP-0166</cite>).</li>
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</ol>
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<p>The parties shall use the nominated candidate for the data transfer. If the nominated candidate is of the proxy type, then the peer has no way to know when it can send data. Therefore the party that offered the nominated candidate MUST send an activated notification to the peer once it has activated the bytestream (as described in <cite>XEP-0065</cite>); it does so by sending a transport-info message containing an <activated/> element as follows.</p>
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<example caption="Responder informs initiator that bytestream has been activated"><![CDATA[
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<iq from='juliet@capulet.lit/balcony'
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id='bv73bs91'
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to='romeo@montague.lit/orchard'
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type='set'>
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<jingle xmlns='urn:xmpp:jingle:1'>
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action='transport-info'
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initiator='romeo@montague.lit/orchard'
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sid='a73sjjvkla37jfea'>
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<content creator='initiator' name='stub'>
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<transport xmlns='urn:xmpp:jingle:transports:s5b:1'
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sid='vj3hs98y'>
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<activated cid='xmdh4b7i'/>
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</transport>
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</content>
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</jingle>
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</iq>
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]]></example>
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</section2>
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<section2 topic='Closing the Bytestream' anchor='close'>
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<p>Once the parties have finished using the bytestream (e.g., because a complete file has been sent), either party can send a Jingle session-terminate action.</p>
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<example caption="Initiator terminates the session"><![CDATA[
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<iq from='romeo@montague.lit/orchard'
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id='hz81vf48'
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to='juliet@capulet.lit/balcony'
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type='set'>
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<jingle xmlns='urn:xmpp:jingle:1'
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action='session-terminate'
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initiator='romeo@montague.lit/orchard'
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sid='a73sjjvkla37jfea'>
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<reason><success/></reason>
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</jingle>
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</iq>
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]]></example>
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<p>The other party then acknowledges the session-terminate and the Jingle session is finished.</p>
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<example caption="Responder acknowledges session-terminate"><![CDATA[
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<iq from='juliet@capulet.lit/balcony'
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id='hz81vf48'
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to='romeo@montague.lit/orchard'
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type='result'/>
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]]></example>
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</section2>
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</section1>
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<section1 topic='Fallback to IBB' anchor='fallback'>
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<p>If the SOCKS5 Bytestreams negotiation fails, the parties might want to "fall back" to the transport of last resort, which for a streaming transport is typically &xep0047; as described for Jingle in &xep0261;. The protocol flow is as follows.</p>
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<code><![CDATA[
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Romeo Juliet
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| |
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| session-initiate |
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| (with S5B info) |
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|--------------------------------->|
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| ack |
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|<---------------------------------|
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| session-accept |
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| (with S5B info) |
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|<---------------------------------|
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| [ SOCKS5 failure! ] |
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|x--------------------------------x|
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| transport-replace (IBB) |
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|--------------------------------->|
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| ack |
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|<---------------------------------|
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| IBB "SESSION" |
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|=================================>|
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| terminate |
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|<---------------------------------|
|
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| ack |
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|--------------------------------->|
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| |
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]]></code>
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<p>First the initiator sends a Jingle session-initiate, in this case with a transport of SOCKS5 Bytestreams. The protocol flow is exactly the same as described above. If both clients are unable to connect to a candidate provided by the peer, both send candidate-error messages and SOCKS5 as failed. The initiator MUST either terminate the Jingle session with a Jingle reason of <connectivity-error/> or replace the transport with something else using the transport-replace action. Typically the fallback option is IBB. Therefore the initiator sends a transport-replace action including a transport of IBB.</p>
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<example caption="Initiator replaces transport with IBB"><![CDATA[
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<iq from='romeo@montague.lit/orchard'
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id='hs92n57'
|
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to='juliet@capulet.lit/balcony'
|
|
type='set'>
|
|
<jingle xmlns='urn:xmpp:jingle:1'
|
|
action='transport-replace'
|
|
initiator='romeo@montague.lit/orchard'
|
|
sid='a73sjjvkla37jfea'>
|
|
<content creator='initiator' name='stub'>
|
|
<transport xmlns='urn:xmpp:jingle:transports:ibb:0'
|
|
block-size='4096'
|
|
sid='ch3d9s71'/>
|
|
</content>
|
|
</jingle>
|
|
</iq>
|
|
]]></example>
|
|
<p>The responder then acknowledges the transport-replace action.</p>
|
|
<example caption="Responder acknowledges transport-replace"><![CDATA[
|
|
<iq from='juliet@capulet.lit/balcony'
|
|
id='hs92n57'
|
|
to='romeo@montague.lit/orchard'
|
|
type='result'/>
|
|
]]></example>
|
|
<p>If the transport replacement is acceptable, the responder then sends a transport-accept action to the initiator (if not, the responder sends a transport-reject action).</p>
|
|
<example caption="Responder sends transport-accept"><![CDATA[
|
|
<iq from='juliet@capulet.lit/balcony'
|
|
id='is71ns63'
|
|
to='romeo@montague.lit/orchard'
|
|
type='set'>
|
|
<jingle xmlns='urn:xmpp:jingle:1'
|
|
action='transport-accept'
|
|
initiator='romeo@montague.lit/orchard'
|
|
sid='a73sjjvkla37jfea'>
|
|
<content creator='initiator' name='stub'>
|
|
<transport xmlns='urn:xmpp:jingle:transports:ibb:0'
|
|
block-size='4096'
|
|
sid='ch3d9s71'/>
|
|
</content>
|
|
</jingle>
|
|
</iq>
|
|
]]></example>
|
|
<p>The initiator acknowledges the Jingle transport-accept action.</p>
|
|
<example caption="Initiator acknowledges transport-accept"><![CDATA[
|
|
<iq from='juliet@capulet.lit/balcony'
|
|
id='is71ns63'
|
|
to='romeo@montague.lit/orchard'
|
|
type='result'/>
|
|
]]></example>
|
|
<p>Now the initiator sends data using In-Band Bytestreams as defined in <cite>XEP-0047</cite>.</p>
|
|
</section1>
|
|
|
|
<section1 topic='Processing Rules and Usage Guidelines' anchor='rules'>
|
|
<p>The same processing rules and usage guidelines defined in XEP-0065 apply to the Jingle S5B Transport Method. Additional implementation suggestions are:</p>
|
|
<ol>
|
|
<li>A client SHOULD try the offered candidates in the order of their priority.</li>
|
|
<li>If more than one <candidate/> element is present a client SHOULD wait 200ms before trying the next one.</li>
|
|
<li>If the candidate has a JID attribute and that JID is not the one of the peer it indicates the usage of a proxy. If the client had offered direct connection information it MAY want to wait a little bit longer than 200ms before trying the first proxy.</li>
|
|
<li>A client SHOULD NOT wait for a TCP timeout on connect. If it is unable to connect to any candidate within 5 seconds it SHOULD send a candidate-error to the other party.</li>
|
|
</ol>
|
|
</section1>
|
|
|
|
<section1 topic='Determining Support' anchor='support'>
|
|
<p>To advertise its support for the Jingle SOCKS5 Bytestreams Transport Method, when replying to &xep0030; information requests an entity MUST return URNs for any version of this protocol that the entity supports -- e.g., "urn:xmpp:jingle:transports:s5b:1" for this version &VNOTE;.</p>
|
|
<example caption="Service discovery information request"><![CDATA[
|
|
<iq from='romeo@montague.lit/orchard'
|
|
id='uw72g176'
|
|
to='juliet@capulet.lit/balcony'
|
|
type='get'>
|
|
<query xmlns='http://jabber.org/protocol/disco#info'/>
|
|
</iq>
|
|
]]></example>
|
|
<example caption="Service discovery information response"><![CDATA[
|
|
<iq from='juliet@capulet.lit/balcony'
|
|
id='uw72g176'
|
|
to='romeo@montague.lit/orchard'
|
|
type='result'>
|
|
<query xmlns='http://jabber.org/protocol/disco#info'>
|
|
<feature var='urn:xmpp:jingle:1'/>
|
|
<feature var='urn:xmpp:jingle:transports:s5b:1'/>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
<p>In order for an application to determine whether an entity supports this protocol, where possible it SHOULD use the dynamic, presence-based profile of service discovery defined in &xep0115;. However, if an application has not received entity capabilities information from an entity, it SHOULD use explicit service discovery instead.</p>
|
|
</section1>
|
|
|
|
<section1 topic='Security Considerations' anchor='security'>
|
|
<section2 topic='Sharing IP Addresses' anchor='security-sharing'>
|
|
<p>The exchange of candidates might result in exposure of the sender's IP addresses, which comprise a form of personally identifying information. A Jingle client MUST enable a user to control which entities will be allowed to receive such information. If a human user explicitly accepts a session request, then the client SHOULD consider that action to imply approval of IP address sharing. However, waiting for a human user to explicitly accept the session request can result in delays during session setup, since it is more efficient to immediately begin sharing transport candidates. Therefore, it is RECOMMENDED for the client to immediately send transport candidates to a contact (without waiting for explicit user approval of the session request) in the following cases:</p>
|
|
<ol>
|
|
<li>The user has permanently and formally authorized the contact to view the user's presence information via a presence subscription as reflected in an XMPP roster item (see &xmppim;).</li>
|
|
<li>The user has temporarily and dynamically shared presence with the contact via "directed presence" as described in <cite>RFC 3921</cite>.</li>
|
|
<li>The user has explicitly added the contact to a "whitelist" of entities who are allowed to access the user's personally-identifying information.</li>
|
|
</ol>
|
|
</section2>
|
|
<section2 topic='Encryption of Media' anchor='security-media'>
|
|
<p>A Jingle implementation SHOULD support security preconditions that are enforced before application media is allowed to flow over the bytestream, such as those described in &xtls;.</p>
|
|
</section2>
|
|
</section1>
|
|
|
|
<section1 topic='IANA Considerations' anchor='iana'>
|
|
<p>This document requires no interaction with &IANA;.</p>
|
|
</section1>
|
|
|
|
<section1 topic='XMPP Registrar Considerations' anchor='registrar'>
|
|
<section2 topic='Jingle Transport Methods' anchor='registrar-transports'>
|
|
<p>The ®ISTRAR; shall add to its registry of Jingle transport methods a definition for the "jingle-s5b" transport method. The registry submission is as follows:</p>
|
|
<code><![CDATA[
|
|
<transport>
|
|
<name>s5b</name>
|
|
<desc>A method for exchanging data over SOCKS5 Bytestreams.</desc>
|
|
<type>streaming</type>
|
|
<doc>XEP-0260</doc>
|
|
</transport>
|
|
]]></code>
|
|
</section2>
|
|
</section1>
|
|
|
|
<section1 topic='Schema' anchor='schema'>
|
|
<code><![CDATA[
|
|
<?xml version='1.0' encoding='UTF-8'?>
|
|
|
|
<xs:schema
|
|
xmlns:xs='http://www.w3.org/2001/XMLSchema'
|
|
targetNamespace='urn:xmpp:jingle:transports:s5b:1'
|
|
xmlns='urn:xmpp:jingle:transports:s5b:1'
|
|
elementFormDefault='qualified'>
|
|
|
|
<xs:element name='transport'>
|
|
<xs:complexType>
|
|
<xs:choice>
|
|
<xs:element ref='candidate' minOccurs='0' maxOccurs='unbounded'/>
|
|
<xs:element ref='candidate-used' minOccurs='0' maxOccurs='1'/>
|
|
<xs:element name='candidate-error' minOccurs='0' maxOccurs='1' type='empty'/>
|
|
<xs:element ref='activated' minOccurs='0' maxOccurs='1'/>
|
|
</xs:choice>
|
|
<xs:attribute name='sid' type='xs:string' use='optional'/>
|
|
<xs:attribute name='mode' use='optional' default='tcp'>
|
|
<xs:simpleType>
|
|
<xs:restriction base='xs:NCName'>
|
|
<xs:enumeration value='tcp'/>
|
|
<xs:enumeration value='udp'/>
|
|
</xs:restriction>
|
|
</xs:simpleType>
|
|
</xs:attribute>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
|
|
<xs:element name='candidate'>
|
|
<xs:complexType>
|
|
<xs:simpleContent>
|
|
<xs:extension base='empty'>
|
|
<xs:attribute name='cid' type='xs:string' use='required'/>
|
|
<xs:attribute name='host' type='xs:string' use='required'/>
|
|
<xs:attribute name='jid' type='xs:string' use='optional'/>
|
|
<xs:attribute name='port' type='xs:positiveInteger' use='optional'/>
|
|
<xs:attribute name='priority' type='xs:positiveInteger' use='required'/>
|
|
<xs:attribute name='type' use='optional' default='direct'>
|
|
<xs:simpleType>
|
|
<xs:restriction base='xs:NCName'>
|
|
<xs:enumeration value='assisted'/>
|
|
<xs:enumeration value='direct'/>
|
|
<xs:enumeration value='proxy'/>
|
|
<xs:enumeration value='tunnel'/>
|
|
</xs:restriction>
|
|
</xs:simpleType>
|
|
</xs:attribute>
|
|
<xs:attribute name='zeroconf' type='xs:string' use='optional'/>
|
|
</xs:extension>
|
|
</xs:simpleContent>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
|
|
<xs:element name='candidate-used'>
|
|
<xs:complexType>
|
|
<xs:simpleContent>
|
|
<xs:extension base='empty'>
|
|
<xs:attribute name='cid' type='xs:string' use='required'/>
|
|
</xs:extension>
|
|
</xs:simpleContent>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
|
|
<xs:element name='activated'>
|
|
<xs:complexType>
|
|
<xs:simpleContent>
|
|
<xs:extension base='empty'>
|
|
<xs:attribute name='cid' type='xs:string' use='required'/>
|
|
</xs:extension>
|
|
</xs:simpleContent>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
|
|
<xs:simpleType name='empty'>
|
|
<xs:restriction base='xs:string'>
|
|
<xs:enumeration value=''/>
|
|
</xs:restriction>
|
|
</xs:simpleType>
|
|
|
|
</xs:schema>
|
|
]]></code>
|
|
</section1>
|
|
</xep>
|