仍然看ejabberd_c2s 這個gen_fsm 模塊。
- RECV <stream:stream to="localhost" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams" version="1.0">
- SENT <?xml version='1.0' encoding='UTF-8'?><stream:stream xmlns:stream="http://etherx.jabber.org/streams" xmlns="jabber:client" from="kinglong" id="7acd9ea9" xml:lang="en" version="1.0">
- SENT <stream:features><starttls xmlns="urn:ietf:params:xml:ns:xmpp-tls"></starttls>
- <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
- <mechanism>DIGEST-MD5</mechanism>
- <mechanism>JIVE-SHAREDSECRET</mechanism>
- <mechanism>PLAIN</mechanism>
- <mechanism>ANONYMOUS</mechanism>
- <mechanism>CRAM-MD5</mechanism>
- </mechanisms>
- <compression xmlns="http://jabber.org/features/compress">
- <method>zlib</method>
- </compression>
- <auth xmlns="http://jabber.org/features/iq-auth"/>
- <register xmlns="http://jabber.org/features/iq-register"/>
- </stream:features>
- RECV <starttls xmlns="urn:ietf:params:xml:ns:xmpp-tls"/>
- RECV <stream:stream to="kinglong" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams" version="1.0">
- SENT <?xml version='1.0' encoding='UTF-8'?>
- <stream:stream xmlns:stream="http://etherx.jabber.org/streams" xmlns="jabber:client" from="kinglong" id="7acd9ea9" xml:lang="en" version="1.0">
- <stream:features>
- <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
- <mechanism>DIGEST-MD5</mechanism>
- <mechanism>JIVE-SHAREDSECRET</mechanism>
- <mechanism>PLAIN</mechanism>
- <mechanism>ANONYMOUS</mechanism>
- <mechanism>CRAM-MD5</mechanism>
- </mechanisms>
- <compression xmlns="http://jabber.org/features/compress">
- <method>zlib</method>
- </compression>
- <auth xmlns="http://jabber.org/features/iq-auth"/>
- <register xmlns="http://jabber.org/features/iq-register"/>
- </stream:features>
上面客戶端與服務(wù)器建立連接的初始幾步直接略過。具體參見ejabberd分析(二),重點看下面的交互:
注:目前的狀態(tài)為wait_for_feature_request
客戶端發(fā)送如下的鑒權(quán)請求給服務(wù)器:
<auth mechanism="DIGEST-MD5" xmlns="urn:ietf:params:xml:ns:xmpp-sasl"></auth>
服務(wù)器端匹配到
- case {xml:get_attr_s("xmlns", Attrs), Name} of
- {?NS_SASL, "auth"} when not ((SockMod == gen_tcp) and TLSRequired) ->
同時獲取客戶端選擇的加密方式(DIGEST-MD5)。匹配到以下路徑:
- case cyrsasl:server_start(StateData#state.sasl_state,
- Mech,
- ClientIn) of
- .........
- {continue, ServerOut, NewSASLState} ->
- send_element(StateData,
- {xmlelement, "challenge",
- [{"xmlns", ?NS_SASL}],
- [{xmlcdata,
- jlib:encode_base64(ServerOut)}]}),
- fsm_next_state(wait_for_sasl_response,
- StateData#state{
- sasl_state = NewSASLState});
以上代碼會向客戶端發(fā)送challenge并將狀態(tài)設(shè)置為wait_for_sasl_response:
<challenge xmlns="urn:ietf:params:xml:ns:xmpp-sasl">cmVhbG09Imtpbmdsb25nIixub25jZT0iQXZ4aFNmYXo3ZlpmMWpqdXh2Qmo4ZTF2SUZQRHNPWDdPUWVXVEFTdiIscW9wPSJhdXRoIixjaGFyc2V0PXV0Zi04LGFsZ29yaXRobT1tZDUtc2Vzcw==</challenge>
客戶端收到后返回響應(yīng):
<response xmlns="urn:ietf:params:xml:ns:xmpp-sasl">Y2hhcnNldD11dGYtOCx1c2VybmFtZT0iMTU1NTUyMTU1NTQiLHJlYWxtPSJraW5nbG9uZyIsbm9uY2U9IkF2eGhTZmF6N2ZaZjFqanV4dkJqOGUxdklGUERzT1g3T1FlV1RBU3YiLG5jPTAwMDAwMDAxLGNub25jZT0icUlaU05ORjNGVmFRN0UzRklKUXI2UFpYaHZTa0hvOFkrZ2ZBVjJ0VCIsZGlnZXN0LXVyaT0ieG1wcC9raW5nbG9uZyIsbWF4YnVmPTY1NTM2LHJlc3BvbnNlPWYxNGM0NDc4NWYwMzNlMDZkNTE1Y2I3MjI4MzVlZmI2LHFvcD1hdXRoLGF1dGh6aWQ9IjE1NTU1MjE1NTU0Ig==</response>
xmpp的驗證機制可參照網(wǎng)上的資料。
這里啰嗦兩句:
前面的<starttls xmlns="urn:ietf:params:xml:ns:xmpp-tls"/>就是在進行TLS握手。先通過TLS傳輸密鑰給客戶端,再使用此密鑰按照SASL協(xié)議進行用戶名、密碼等驗證。
服務(wù)器端在wait_for_sasl_response函數(shù)中驗證通過后發(fā)送鑒權(quán)通過的消息給客戶端,并將狀態(tài)設(shè)置為wait_for_stream:
<success xmlns="urn:ietf:params:xml:ns:xmpp-sasl">cnNwYXV0aD0wMjFkMjI4MTRmNjcwNDMxMTUxZDMwMTIwYzg3ODg0Ng==</success>
客戶端繼續(xù)發(fā)送如下消息給服務(wù)器,再次初始化一個流。
<stream:stream to="kinglong" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams" version="1.0">
此時服務(wù)器端的狀態(tài)已經(jīng)為驗證通過,但客戶端未綁定資源:
- case StateData#state.authenticated of
- ......
- _ ->
- case StateData#state.resource of
- "" ->
- ......
- StreamFeatures =
- [{xmlelement, "bind",
- [{"xmlns", ?NS_BIND}], []},
- {xmlelement, "session",
- [{"xmlns", ?NS_SESSION}], []}]
- ++ RosterVersioningFeature
- ++ ejabberd_hooks:run_fold(
- c2s_stream_features,
- Server,
- [], [Server]),
服務(wù)器發(fā)送bind給客戶端,并將狀態(tài)設(shè)置為wait_for_bind:
<?xml version='1.0' encoding='UTF-8'?><stream:stream xmlns:stream="http://etherx.jabber.org/streams" xmlns="jabber:client" from="kinglong" id="7acd9ea9" xml:lang="en" version="1.0"><stream:features><compression xmlns="http://jabber.org/features/compress"><method>zlib</method></compression><bind xmlns="urn:ietf:params:xml:ns:xmpp-bind"/><session xmlns="urn:ietf:params:xml:ns:xmpp-session"/></stream:features>
客戶端接收到后發(fā)送bind響應(yīng),綁定自己的資源:
<iq id="T2U7N-0" type="set"><bind xmlns="urn:ietf:params:xml:ns:xmpp-bind"><resource>Spark 2.6.3</resource></bind></iq>
服務(wù)器端在wait_for_bind 函數(shù)中進行資源沖突的檢查,完成綁定后返回成功的消息,并將狀態(tài)設(shè)置為wait_for_session,等待客戶端建立session:
<iq type="result" id="T2U7N-0" to="kinglong/7acd9ea9"><bind xmlns="urn:ietf:params:xml:ns:xmpp-bind"><jid>12345678910@kinglong/Spark 2.6.3</jid></bind></iq>
客戶端發(fā)送session請求給服務(wù)器端:
<iq id="T2U7N-1" type="set"><session xmlns="urn:ietf:params:xml:ns:xmpp-session"/></iq>
服務(wù)器端的wait_for_session函數(shù)中:
- case jlib:iq_query_info(El) of
- #iq{type = set, xmlns = ?NS_SESSION} ->
- ......
- Res = jlib:make_result_iq_reply(El),
- send_element(StateData, Res),
對消息進行判斷,成功后然后返回result消息:
<iq type="result" id="T2U7N-1" to="15555215554@kinglong/Spark 2.6.3"><session xmlns="urn:ietf:params:xml:ns:xmpp-session"/></iq>
接下來調(diào)用
- ejabberd_sm:open_session(
- SID, U, StateData#state.server, R, Info)
來創(chuàng)建session,并將狀態(tài)設(shè)置為session_established,并在session_established2中處理接下來的客戶端消息。