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00e4d116a7
This has been discussed on dccp@vger and removes the necessity for applications to supply service codes in each and every case. If an application does not want to provide a service code, that's fine, it will be given 0. Otherwise, service codes can be set via socket options as before. This patch has been tested using various client/server configurations (including listening on multiple service codes). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
59 lines
1.6 KiB
Plaintext
59 lines
1.6 KiB
Plaintext
DCCP protocol
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============
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Contents
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========
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- Introduction
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- Missing features
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- Socket options
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- Notes
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Introduction
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============
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Datagram Congestion Control Protocol (DCCP) is an unreliable, connection
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based protocol designed to solve issues present in UDP and TCP particularly
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for real time and multimedia traffic.
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It has a base protocol and pluggable congestion control IDs (CCIDs).
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It is at draft RFC status and the homepage for DCCP as a protocol is at:
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http://www.icir.org/kohler/dcp/
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Missing features
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================
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The DCCP implementation does not currently have all the features that are in
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the draft RFC.
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In particular the following are missing:
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- CCID2 support
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- feature negotiation
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When testing against other implementations it appears that elapsed time
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options are not coded compliant to the specification.
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Socket options
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==============
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DCCP_SOCKOPT_PACKET_SIZE is used for CCID3 to set default packet size for
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calculations.
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DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of
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service codes (RFC 4340, sec. 8.1.2); if this socket option is not set,
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the socket will fall back to 0 (which means that no meaningful service code
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is present). Connecting sockets set at most one service option; for
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listening sockets, multiple service codes can be specified.
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Notes
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=====
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SELinux does not yet have support for DCCP. You will need to turn it off or
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else you will get EACCES.
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DCCP does not travel through NAT successfully at present. This is because
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the checksum covers the psuedo-header as per TCP and UDP. It should be
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relatively trivial to add Linux NAT support for DCCP.
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