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authorEric Dumazet <edumazet@google.com>2013-02-21 12:18:52 +0000
committerDavid S. Miller <davem@davemloft.net>2013-02-21 18:15:58 -0500
commit08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664 (patch)
treefc1d00005fda323296b93064416d255b81fdab73 /include/net/inet6_hashtables.h
parent0ab8a9f5fa94ac625c1f19acc48db299416c6d49 (diff)
ipv6: use a stronger hash for tcp
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>
Diffstat (limited to 'include/net/inet6_hashtables.h')
-rw-r--r--include/net/inet6_hashtables.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index 7ca75cbbf75e..fd4ee016ba5c 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -28,16 +28,16 @@
struct inet_hashinfo;
-/* I have no idea if this is a good hash for v6 or not. -DaveM */
static inline unsigned int inet6_ehashfn(struct net *net,
const struct in6_addr *laddr, const u16 lport,
const struct in6_addr *faddr, const __be16 fport)
{
- u32 ports = (lport ^ (__force u16)fport);
+ u32 ports = (((u32)lport) << 16) | (__force u32)fport;
return jhash_3words((__force u32)laddr->s6_addr32[3],
- (__force u32)faddr->s6_addr32[3],
- ports, inet_ehash_secret + net_hash_mix(net));
+ ipv6_addr_jhash(faddr),
+ ports,
+ inet_ehash_secret + net_hash_mix(net));
}
static inline int inet6_sk_ehashfn(const struct sock *sk)