tcp: drop the hash_32() part from the index calculation
authorWilly Tarreau <w@1wt.eu>
Mon, 2 May 2022 08:46:14 +0000 (10:46 +0200)
committerJakub Kicinski <kuba@kernel.org>
Thu, 5 May 2022 02:22:33 +0000 (19:22 -0700)
commite8161345ddbb66e449abde10d2fdce93f867eba9
tree57699c177cf0115d66ca9dc3eec9666d9f0a415d
parent4c2c8f03a5ab7cb04ec64724d7d176d00bcc91e5
tcp: drop the hash_32() part from the index calculation

In commit 190cc82489f4 ("tcp: change source port randomizarion at
connect() time"), the table_perturb[] array was introduced and an
index was taken from the port_offset via hash_32(). But it turns
out that hash_32() performs a multiplication while the input here
comes from the output of SipHash in secure_seq, that is well
distributed enough to avoid the need for yet another hash.

Suggested-by: Amit Klein <aksecurity@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net/ipv4/inet_hashtables.c