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authorEric Dumazet <edumazet@google.com>2013-02-21 12:18:52 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-28 06:32:27 -0800
commitae593067dbed83010fee8ad59bab7948f3d3601f (patch)
treeeb6f227197dbfc218c7f12f7757a56cd644a9524 /include/net
parentb18383129b00d2d6aac160f55e27c5ba1cf9d49b (diff)
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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/net')
-rw-r--r--include/net/inet6_hashtables.h8
-rw-r--r--include/net/inet_sock.h1
-rw-r--r--include/net/ipv6.h12
3 files changed, 17 insertions, 4 deletions
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index e46674d..f9ce2fa 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 14dd9c7..26490b3 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 c39121f..879aadf 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] |