This gives a clear speed and security improvement. Siphash is both
faster and is more solid crypto than the aging MD5.
Rather than manually filling MD5 buffers, for IPv6, we simply create
a layout by a simple anonymous struct, for which gcc generates
rather efficient code. For IPv4, we pass the values directly to the
short input convenience functions.
64-bit x86_64:
[ 1.683628] secure_tcpv6_sequence_number_md5# cycles: 99563527
[ 1.717350] secure_tcp_sequence_number_md5# cycles: 92890502
[ 1.741968] secure_tcpv6_sequence_number_siphash# cycles: 67825362
[ 1.762048] secure_tcp_sequence_number_siphash# cycles: 67485526
32-bit x86:
[ 1.600012] secure_tcpv6_sequence_number_md5# cycles: 103227892
[ 1.634219] secure_tcp_sequence_number_md5# cycles: 94732544
[ 1.669102] secure_tcpv6_sequence_number_siphash# cycles: 96299384
[ 1.700165] secure_tcp_sequence_number_siphash# cycles: 86015473
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Miller <davem@davemloft.net>
Cc: David Laight <David.Laight@aculab.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
7cd23e5300