From: Florian Westphal Date: Fri, 20 Sep 2013 20:32:55 +0000 (+0200) Subject: tcp: syncookies: reduce cookie lifetime to 128 seconds X-Git-Tag: v3.13-rc1~105^2~316 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8c27bd75f04fb9cb70c69c3cfe24f4e6d8e15906;p=pandora-kernel.git tcp: syncookies: reduce cookie lifetime to 128 seconds We currently accept cookies that were created less than 4 minutes ago (ie, cookies with counter delta 0-3). Combined with the 8 mss table values, this yields 32 possible values (out of 2**32) that will be valid. Reducing the lifetime to < 2 minutes halves the guessing chance while still providing a large enough period. While at it, get rid of jiffies value -- they overflow too quickly on 32 bit platforms. getnstimeofday is used to create a counter that increments every 64s. perf shows getnstimeofday cost is negible compared to sha_transform; normal tcp initial sequence number generation uses getnstimeofday, too. Reported-by: Jakob Lell Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- Reading git-diff-tree failed