linux/net/dccp
Gerrit Renker 9eca0a47de dccp: Resolve dependencies of features on choice of CCID
This provides a missing link in the code chain, as several features implicitly
depend and/or rely on the choice of CCID. Most notably, this is the Send Ack Vector
feature, but also Ack Ratio and Send Loss Event Rate (also taken care of).

For Send Ack Vector, the situation is as follows:
 * since CCID2 mandates the use of Ack Vectors, there is no point in allowing 
   endpoints which use CCID2 to disable Ack Vector features such a connection;

 * a peer with a TX CCID of CCID2 will always expect Ack Vectors, and a peer
   with a RX CCID of CCID2 must always send Ack Vectors (RFC 4341, sec. 4);

 * for all other CCIDs, the use of (Send) Ack Vector is optional and thus
   negotiable. However, this implies that the code negotiating the use of Ack
   Vectors also supports it (i.e. is able to supply and to either parse or
   ignore received Ack Vectors). Since this is not the case (CCID-3 has no Ack
   Vector support), the use of Ack Vectors is here disabled, with a comment
   in the source code.

An analogous consideration arises for the Send Loss Event Rate feature,
since the CCID-3 implementation does not support the loss interval options
of RFC 4342. To make such use explicit, corresponding feature-negotiation
options are inserted which signal the use of the loss event rate option,
as it is used by the CCID3 code.

Lastly, the values of the Ack Ratio feature are matched to the choice of CCID.

The patch implements this as a function which is called after the user has
made all other registrations for changing default values of features.

The table is variable-length, the reserved (and hence for feature-negotiation
invalid, confirmed by considering section 19.4 of RFC 4340) feature number `0'
is used to mark the end of the table.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-12 00:48:44 -08:00
..
ccids dccp: Registration routines for changing feature values 2008-11-12 00:43:40 -08:00
ackvec.c This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
ackvec.h This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
ccid.c dccp: Query supported CCIDs 2008-11-12 00:47:26 -08:00
ccid.h dccp: Query supported CCIDs 2008-11-12 00:47:26 -08:00
dccp.h dccp: Resolve dependencies of features on choice of CCID 2008-11-12 00:48:44 -08:00
diag.c This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
feat.c dccp: Resolve dependencies of features on choice of CCID 2008-11-12 00:48:44 -08:00
feat.h dccp: Registration routines for changing feature values 2008-11-12 00:43:40 -08:00
input.c dccp: Per-socket initialisation of feature negotiation 2008-11-04 23:55:49 -08:00
ipv4.c dccp: Cleanup routines for feature negotiation 2008-11-04 23:56:30 -08:00
ipv6.c dccp: Cleanup routines for feature negotiation 2008-11-04 23:56:30 -08:00
ipv6.h Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
Kconfig This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
Makefile This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
minisocks.c dccp: Per-socket initialisation of feature negotiation 2008-11-04 23:55:49 -08:00
options.c dccp: Limit feature negotiation to connection setup phase 2008-11-12 00:42:58 -08:00
output.c dccp: Resolve dependencies of features on choice of CCID 2008-11-12 00:48:44 -08:00
probe.c net: replace NIPQUAD() in net/*/ 2008-10-31 00:54:56 -07:00
proto.c dccp: Resolve dependencies of features on choice of CCID 2008-11-12 00:48:44 -08:00
sysctl.c This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
timer.c dccp: Limit feature negotiation to connection setup phase 2008-11-12 00:42:58 -08:00