[DCCP] CCID2: Initial CCID2 (TCP-Like) implementation

Original work by Andrea Bittau, Arnaldo Melo cleaned up and fixed several
issues on the merge process.

For now CCID2 was turned the default for all SOCK_DCCP connections, but this
will be remedied soon with the merge of the feature negotiation code.

Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 36 insertions, 3 deletions

diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
index 7684d83946a..422af197171 100644
--- a/net/dccp/ccids/Kconfig
+++ b/net/dccp/ccids/Kconfig
@@ -1,6 +1,34 @@
 menu "DCCP CCIDs Configuration (EXPERIMENTAL)"
         depends on IP_DCCP && EXPERIMENTAL
 
+config IP_DCCP_CCID2
+        tristate "CCID2 (TCP) (EXPERIMENTAL)"
+        depends on IP_DCCP
+        select IP_DCCP_ACKVEC
+        ---help---
+          CCID 2, TCP-like Congestion Control, denotes Additive Increase,
+          Multiplicative Decrease (AIMD) congestion control with behavior
+          modelled directly on TCP, including congestion window, slow start,
+          timeouts, and so forth [RFC 2581].  CCID 2 achieves maximum
+          bandwidth over the long term, consistent with the use of end-to-end
+          congestion control, but halves its congestion window in response to
+          each congestion event.  This leads to the abrupt rate changes
+          typical of TCP.  Applications should use CCID 2 if they prefer
+          maximum bandwidth utilization to steadiness of rate.  This is often
+          the case for applications that are not playing their data directly
+          to the user.  For example, a hypothetical application that
+          transferred files over DCCP, using application-level retransmissions
+          for lost packets, would prefer CCID 2 to CCID 3.  On-line games may
+          also prefer CCID 2.
+
+          CCID 2 is further described in:
+          http://www.icir.org/kohler/dccp/draft-ietf-dccp-ccid2-10.txt
+
+          This text was extracted from:
+          http://www.icir.org/kohler/dccp/draft-ietf-dccp-spec-13.txt
+
+          If in doubt, say M.
+
 config IP_DCCP_CCID3
         tristate "CCID3 (TFRC) (EXPERIMENTAL)"
         depends on IP_DCCP
@@ -15,10 +43,15 @@ config IP_DCCP_CCID3
           suitable than CCID 2 for applications such streaming media where a
           relatively smooth sending rate is of importance.
 
-          CCID 3 is further described in [CCID 3 PROFILE]. The TFRC
-          congestion control algorithms were initially described in RFC 3448.
+          CCID 3 is further described in:
+
+          http://www.icir.org/kohler/dccp/draft-ietf-dccp-ccid3-11.txt.
+
+          The TFRC congestion control algorithms were initially described in
+          RFC 3448.
 
-          This text was extracted from draft-ietf-dccp-spec-11.txt.
+          This text was extracted from:
+          http://www.icir.org/kohler/dccp/draft-ietf-dccp-spec-13.txt
           
           If in doubt, say M.