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| author | Eric Dumazet <edumazet@google.com> | 2013-02-21 12:18:52 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-02-21 18:15:58 -0500 |
| commit | 08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664 (patch) | |
| tree | fc1d00005fda323296b93064416d255b81fdab73 /include/net/ipv6.h | |
| parent | 0ab8a9f5fa94ac625c1f19acc48db299416c6d49 (diff) | |
| download | linux-3.10-08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664.tar.gz linux-3.10-08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664.tar.bz2 linux-3.10-08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664.zip | |
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/ipv6.h')
| -rw-r--r-- | include/net/ipv6.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 851d5412a29..64d12e77719 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -15,6 +15,7 @@ #include <linux/ipv6.h> #include <linux/hardirq.h> +#include <linux/jhash.h> #include <net/if_inet6.h> #include <net/ndisc.h> #include <net/flow.h> @@ -514,6 +515,17 @@ static inline u32 ipv6_addr_hash(const struct in6_addr *a) #endif } +/* more secured version of ipv6_addr_hash() */ +static inline u32 ipv6_addr_jhash(const struct in6_addr *a) +{ + u32 v = (__force u32)a->s6_addr32[0] ^ (__force u32)a->s6_addr32[1]; + + return jhash_3words(v, + (__force u32)a->s6_addr32[2], + (__force u32)a->s6_addr32[3], + ipv6_hash_secret); +} + static inline bool ipv6_addr_loopback(const struct in6_addr *a) { #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 |