From 30e502a34b8b21fae2c789da102bd9f6e99fef83 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 26 Sep 2014 22:37:33 +0200 Subject: [PATCH] net: tcp: add flag for ca to indicate that ECN is required This patch adds a flag to TCP congestion algorithms that allows for requesting to mark IPv4/IPv6 sockets with transport as ECN capable, that is, ECT(0), when required by a congestion algorithm. It is currently used and needed in DataCenter TCP (DCTCP), as it requires both peers to assert ECT on all IP packets sent - it uses ECN feedback (i.e. CE, Congestion Encountered information) from switches inside the data center to derive feedback to the end hosts. Therefore, simply add a new flag to icsk_ca_ops. Note that DCTCP's algorithm/behaviour slightly diverges from RFC3168, therefore this is only (!) enabled iff the assigned congestion control ops module has requested this. By that, we can tightly couple this logic really only to the provided congestion control ops. Joint work with Florian Westphal and Glenn Judd. Signed-off-by: Daniel Borkmann Signed-off-by: Florian Westphal Signed-off-by: Glenn Judd Acked-by: Stephen Hemminger Signed-off-by: David S. Miller --- Reading git-format-patch failed