ipv6: use a stronger hash for tcp
[ Upstream commit 08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664 ]
It looks like its possible to open thousands of TCP IPv6
sessions on a server, all landing in a single slot of TCP hash
table. Incoming packets have to lookup sockets in a very
long list.
We should hash all bits from foreign IPv6 addresses, using
a salt and hash mix, not a simple XOR.
inet6_ehashfn() can also separately use the ports, instead
of xoring them.
Reported-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index ae17e13..8cd2e1d 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -202,6 +202,7 @@
extern int inet_sk_rebuild_header(struct sock *sk);
extern u32 inet_ehash_secret;
+extern u32 ipv6_hash_secret;
extern void build_ehash_secret(void);
static inline unsigned int inet_ehashfn(struct net *net,