Commit Graph

9 Commits

Author SHA1 Message Date
Gerrit Renker 129fa44785 dccp: Integrate the TFRC library with DCCP
This patch integrates the TFRC library, which is a dependency of CCID-3 (and
CCID-4), with the new use of CCIDs in the DCCP module.		

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-04 21:45:33 -08:00
Gerrit Renker 7deb0f8510 dccp ccid-3: X truncated due to type conversion
This fixes a bug in computing the inter-packet-interval t_ipi = s/X: 

 scaled_div32(a, b) uses u32 for b, but in "scaled_div32(s, X)" the type of the
 sending rate `X' is u64. Since X is scaled by 2^6, this truncates rates greater
 than 2^26 Bps (~537 Mbps).

Using full 64-bit division now.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-06-11 11:19:10 +01:00
Gerrit Renker 1e2f0e5e83 dccp: Fix sparse warnings
This patch fixes the following sparse warnings:
 * nested min(max()) expression:
   net/dccp/ccids/ccid3.c:91:21: warning: symbol '__x' shadows an earlier one
   net/dccp/ccids/ccid3.c:91:21: warning: symbol '__y' shadows an earlier one
   
 * Declaration of function prototypes in .c instead of .h file, resulting in
   "should it be static?" warnings. 

 * Declared "struct dccpw" static (local to dccp_probe).
 
 * Disabled dccp_delayed_ack() - not fully removed due to RFC 4340, 11.3
   ("Receivers SHOULD implement delayed acknowledgement timers ...").

 * Used a different local variable name to avoid
   net/dccp/ackvec.c:293:13: warning: symbol 'state' shadows an earlier one
   net/dccp/ackvec.c:238:33: originally declared here

 * Removed unused functions `dccp_ackvector_print' and `dccp_ackvec_print'.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-06-11 11:19:09 +01:00
Gerrit Renker 8a9c7e92e0 [TFRC]: Ringbuffer to track loss interval history
A ringbuffer-based implementation of loss interval history is easier to
maintain, allocate, and update.

The `swap' routine to keep the RX history sorted is due to and was written
by Arnaldo Carvalho de Melo, simplifying an earlier macro-based variant.

Details:
 * access to the Loss Interval Records via macro wrappers (with safety checks);
 * simplified, on-demand allocation of entries (no extra memory consumption on
   lossless links); cache allocation is local to the module / exported as service;
 * provision of RFC-compliant algorithm to re-compute average loss interval;
 * provision of comprehensive, new loss detection algorithm
 	- support for all cases of loss, including re-ordered/duplicate packets;
 	- waiting for NDUPACK=3 packets to fill the hole;
	- updating loss records when a late-arriving packet fills a hole.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:57:18 -08:00
Gerrit Renker c40616c597 [TFRC]: Provide central source file and debug facility
This patch changes the tfrc_lib module in the following manner:

 (1) a dedicated tfrc source file to call the packet history &
     loss interval init/exit functions.
 (2) a dedicated tfrc_pr_debug macro with toggle switch `tfrc_debug'.

Commiter note: renamed tfrc_module.c to tfrc.c, and made CONFIG_IP_DCCP_CCID3
select IP_DCCP_TFRC_LIB.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:56:39 -08:00
Gerrit Renker c3ada46a00 [CCID3]: Inline for moving average
The moving average computation occurs so frequently in the CCID 3 code that
it merits an inline function  of its own. This is uses a suggestion by
Arnaldo as per http://www.mail-archive.com/dccp@vger.kernel.org/msg01662.html

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:54:43 -08:00
Gerrit Renker d63d8364cf [DCCP]: Simplify TFRC calculation
In migrating towards using the newer functions scaled_div/scaled_div32
for TFRC computations mapped from floating-point onto integer arithmetic,
this completes the last stage of modifications.

In particular, the overflow case for computing X_calc is circumvented by
 * breaking the computation into two stages
 * the first stage, res = (s*1E6)/R, cannot overflow due to use of u64
 * in the second stage, res = (res*1E6)/f, overflow on u32 is avoided due
   to (i) returning UINT_MAX in this case (which is logically appropriate)
   and (ii) issuing a warning message into the system log (since very likely
   there is a problem somewhere else with the parameters)

Lastly, all such scaling operations are now exported into tfrc.h, since
actually this form of scaled computation is specific to TFRC and not to CCID3.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-11 14:34:46 -08:00
Ian McDonald e6bccd3573 [DCCP]: Update contact details and copyright
Just updating copyright and contacts

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 19:01:30 -07:00
Arnaldo Carvalho de Melo 36729c1a73 [DCCP]: Move the calc_X routines to dccp_tfrc_lib
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 16:12:47 -07:00