From patchwork Thu Feb 28 14:44:41 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 224100 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id BF9662C02A0 for ; Fri, 1 Mar 2013 01:51:28 +1100 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UB4pI-0000Z5-Jz; Thu, 28 Feb 2013 14:51:16 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UB4pH-0000YA-J5 for kernel-team@lists.ubuntu.com; Thu, 28 Feb 2013 14:51:15 +0000 Received: from [188.250.143.69] (helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UB4pH-0001Vr-0t; Thu, 28 Feb 2013 14:51:15 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 131/139] ipv6: use a stronger hash for tcp Date: Thu, 28 Feb 2013 14:44:41 +0000 Message-Id: <1362062689-2567-132-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1362062689-2567-1-git-send-email-luis.henriques@canonical.com> References: <1362062689-2567-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Cc: Eric Dumazet , Yuchung Cheng , "David S. Miller" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.5.7.7 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit 08dcdbf6a7b9d14c2302c5bd0c5390ddf122f664 upstream. 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 Signed-off-by: Eric Dumazet Cc: Yuchung Cheng Signed-off-by: David S. Miller Signed-off-by: Luis Henriques --- include/net/inet6_hashtables.h | 8 ++++---- include/net/inet_sock.h | 1 + include/net/ipv6.h | 12 ++++++++++++ net/ipv4/af_inet.c | 9 +++++++-- 4 files changed, 24 insertions(+), 6 deletions(-) diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h index 00cbb43..2da45ce 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 ae17e13..8cd2e1d 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -202,6 +202,7 @@ 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 aecf884..c11fa5d 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -15,6 +15,7 @@ #include #include +#include #include #include #include @@ -395,6 +396,17 @@ static inline bool ipv6_addr_any(const struct in6_addr *a) a->s6_addr32[2] | a->s6_addr32[3]) == 0; } +/* 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) { return (a->s6_addr32[0] | a->s6_addr32[1] | diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index c8f7aee..57b3024 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -227,8 +227,12 @@ EXPORT_SYMBOL(inet_listen); u32 inet_ehash_secret __read_mostly; EXPORT_SYMBOL(inet_ehash_secret); +u32 ipv6_hash_secret __read_mostly; +EXPORT_SYMBOL(ipv6_hash_secret); + /* - * inet_ehash_secret must be set exactly once + * inet_ehash_secret must be set exactly once, and to a non nul value + * ipv6_hash_secret must be set exactly once. */ void build_ehash_secret(void) { @@ -238,7 +242,8 @@ void build_ehash_secret(void) get_random_bytes(&rnd, sizeof(rnd)); } while (rnd == 0); - cmpxchg(&inet_ehash_secret, 0, rnd); + if (cmpxchg(&inet_ehash_secret, 0, rnd) == 0) + get_random_bytes(&ipv6_hash_secret, sizeof(ipv6_hash_secret)); } EXPORT_SYMBOL(build_ehash_secret);