linux/net/dccp
Gerrit Renker 88ddac513a dccp: Special case of the MPS for client-PARTOPEN with DataAcks
To increase robustness, it is necessary to resend Confirm feature-negotiation
options, even though the RFC does not mandate it. But feature negotiation
options can take (much) more room than the options on common DataAck packets.

Instead of reducing the MPS always for a case which only applies to the three
messages send during initial handshake, this patch devises a special case:

   if the payload length of the DataAck in PARTOPEN is too large, an Ack is sent
   to carry the options, and the feature-negotiation list is then flushed.

   This means that the server gets two Acks for one Response. If both Acks get
   lost, it is probably better to restart the connection anyway and devising yet
   another special-case does not seem worth the extra complexity.

The patch (over-)estimates the expected overhead to be 32*4 bytes -- commonly
seen values were 20-90 bytes for initial feature-negotiation options. 

It uses sizeof(u32) to mean "aligned units of 4 bytes". For consistency,
another use of sizeof is modified.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:33 +02:00
..
ccids dccp: Registration routines for changing feature values 2008-09-04 07:45:27 +02:00
ackvec.c dccp: Set per-connection CCIDs via socket options 2008-09-04 07:45:28 +02:00
ackvec.h dccp: Leave headroom for options when calculating the MPS 2008-09-04 07:45:33 +02:00
ccid.c dccp: Auto-load (when supported) CCID plugins for negotiation 2008-09-04 07:45:31 +02:00
ccid.h dccp: Auto-load (when supported) CCID plugins for negotiation 2008-09-04 07:45:31 +02:00
dccp.h dccp: Special case of the MPS for client-PARTOPEN with DataAcks 2008-09-04 07:45:33 +02:00
diag.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-09-04 07:45:31 +02:00
feat.c dccp ccid-2: Use feature-negotiation to report Ack Ratio changes 2008-09-04 07:45:32 +02:00
feat.h dccp: Debugging functions for feature negotiation 2008-09-04 07:45:32 +02:00
input.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-09-04 07:45:31 +02:00
ipv4.c dccp: Cleanup routines for feature negotiation 2008-09-04 07:45:26 +02:00
ipv6.c dccp: Cleanup routines for feature negotiation 2008-09-04 07:45:26 +02:00
ipv6.h Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
Kconfig [DCCP]: Promote CCID2 as default CCID 2008-01-28 14:54:46 -08:00
Makefile [DCCPv6]: Resolve conditional build problem 2006-12-02 21:22:28 -08:00
minisocks.c dccp: Implement both feature-local and feature-remote Sequence Window feature 2008-09-04 07:45:32 +02:00
options.c dccp: Debugging functions for feature negotiation 2008-09-04 07:45:32 +02:00
output.c dccp: Special case of the MPS for client-PARTOPEN with DataAcks 2008-09-04 07:45:33 +02:00
probe.c dccp: API to query the current TX/RX CCID 2008-09-04 07:45:28 +02:00
proto.c dccp ccid-2: Use feature-negotiation to report Ack Ratio changes 2008-09-04 07:45:32 +02:00
sysctl.c dccp: Initialisation and type-checking of feature sysctls 2008-09-04 07:45:32 +02:00
timer.c dccp: Limit feature negotiation to connection setup phase 2008-09-04 07:45:27 +02:00