diff options
| author | Eric Dumazet <edumazet@google.com> | 2013-02-21 12:18:52 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-28 06:32:27 -0800 |
| commit | ae593067dbed83010fee8ad59bab7948f3d3601f (patch) | |
| tree | eb6f227197dbfc218c7f12f7757a56cd644a9524 /include | |
| parent | b18383129b00d2d6aac160f55e27c5ba1cf9d49b (diff) | |
| download | lwn-ae593067dbed83010fee8ad59bab7948f3d3601f.tar.gz lwn-ae593067dbed83010fee8ad59bab7948f3d3601f.zip | |
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/inet6_hashtables.h | 8 | ||||
| -rw-r--r-- | include/net/inet_sock.h | 1 | ||||
| -rw-r--r-- | include/net/ipv6.h | 12 |
3 files changed, 17 insertions, 4 deletions
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h index e46674d5daea..f9ce2fa4f563 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) diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index 14dd9c789924..26490b37dee8 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -199,6 +199,7 @@ static inline void inet_sk_copy_descendant(struct sock *sk_to, 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, diff --git a/include/net/ipv6.h b/include/net/ipv6.h index c39121f6bc94..879aadf1d0f7 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> @@ -386,6 +387,17 @@ struct ip6_create_arg { void ip6_frag_init(struct inet_frag_queue *q, void *a); int ip6_frag_match(struct inet_frag_queue *q, void *a); +/* 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 int ipv6_addr_any(const struct in6_addr *a) { return (a->s6_addr32[0] | a->s6_addr32[1] | |