| Re: [cf-dev] question of californium.scandium project |
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Hi there „unknown stranger“, from your message I deduce that you are trying to make a DTLS connection over a network with an MTU of 140 bytes, right? The log also indicates
that the client has split up its CLIENT_HELLO message into two fragmented handshake messages which the server is not able to handle correctly, i.e. the server does not re-assemble the fragments into the original CLIENT_HELLO message. We currently do not handle
that case because, frankly spoken, I have not expected to ever receive a fragmented CLIENT_HELLO message (mainly because the CLIENT_HELLO message usually does not contain that much information). May I ask what kind of networking infrastructure you are running on that has an MTU of 140 bytes? BTW It would be nice of you to include your (first) name so that we know who we are talking to ;-) Regards, Kai From: cf-dev-bounces@xxxxxxxxxxx [mailto:cf-dev-bounces@xxxxxxxxxxx]
On Behalf Of ???? Project: scandium project File: org.eclipse.californium.scandium.DTLSConnector.java Question: When I reduce the MTU (" this.maximumTransmissionUnit = 140" at linenumber 298 in function "start"), I run ExampleDTLSServer.java and ExampleDTLSClient.java as application. In ExampleDTLSServer console, there are
org.eclipse.californium.scandium.dtls.FragmentedHandshakeMessage cannot be cast to org.eclipse.californium.scandium.dtls.ClientHello exceptions. I put the output of DTLSClient and DTLSServer's console in DTLSClientLog.txt and DTLSServerLog.txt. When ExampleDTLSServer receive the second ClientHello there are cast exceptions in
processHandshakeRecordWithoutConnection function.
I catch two Records of second ClientHello in processClientHello function.
==[ DTLS Record ]============================================== Content Type: Handshake (22) Peer address: /127.0.0.1:63430 Version: 254, 253 Epoch: 0 Sequence Number: 5 Length: 99 Fragment: Handshake Protocol Type: CLIENT_HELLO (1) Peer: /127.0.0.1:63430 Message Sequence No: 1 Fragment Offset: 0 Fragment Length: 87 Length: 114
Fragmented Handshake Message: 87 bytes
FE FD 56 6A 85 CF 63 FB E2 DA 7F D1 87 FD 78 82 50 E8 9B 5D 43 EF 4C 0A E1 57 4D 83 0F 3B BA CF CE 5C 00 20 BA 77 09 1D B0 66 4B 23 A2 6D 68 BB 16 E1 76 34 33 3D 9D 24 A8 33 82 B6 69 26 6B 21 5E CB C3 82 00 08 C0 AE C0 23 C0 A8 00 AE 01 00 00 20 00 0A
00 08 00 =============================================================== ==[ DTLS Record ]============================================== Content Type: Handshake (22) Peer address: /127.0.0.1:63430 Version: 254, 253 Epoch: 0 Sequence Number: 6 Length: 39 Fragment: Handshake Protocol Type: CLIENT_HELLO (1) Peer: /127.0.0.1:63430 Message Sequence No: 1 Fragment Offset: 87 Fragment Length: 27 Length: 114
Fragmented Handshake Message: 27 bytes
06 00 17 00 18 00 19 00 0B 00 02 01 00 00 13 00 03 02 02 00 00 14 00 03 02 00 02 =============================================================== |
