From 1bbdceef1e535add893bf71d7b7ab102e4eb69eb Mon Sep 17 00:00:00 2001
From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Sat, 19 Oct 2013 21:48:57 +0200
Subject: inet: convert inet_ehash_secret and ipv6_hash_secret to
 net_get_random_once

Initialize the ehash and ipv6_hash_secrets with net_get_random_once.

Each compilation unit gets its own secret now:
  ipv4/inet_hashtables.o
  ipv4/udp.o
  ipv6/inet6_hashtables.o
  ipv6/udp.o
  rds/connection.o

The functions still get inlined into the hashing functions. In the fast
path we have at most two (needed in ipv6) if (unlikely(...)).

Cc: Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/af_inet6.c         |  5 -----
 net/ipv6/inet6_hashtables.c | 15 ++++++++++++---
 net/ipv6/udp.c              | 17 ++++++++++++++---
 3 files changed, 26 insertions(+), 11 deletions(-)

(limited to 'net/ipv6')

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index a2cb07c..20af1fb 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -110,11 +110,6 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol,
 	int try_loading_module = 0;
 	int err;
 
-	if (sock->type != SOCK_RAW &&
-	    sock->type != SOCK_DGRAM &&
-	    !inet_ehash_secret)
-		build_ehash_secret();
-
 	/* Look for the requested type/protocol pair. */
 lookup_protocol:
 	err = -ESOCKTNOSUPPORT;
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index fa7dd38..262e13c 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -29,10 +29,19 @@ static unsigned int inet6_ehashfn(struct net *net,
 				  const struct in6_addr *faddr,
 				  const __be16 fport)
 {
-	const u32 lhash = (__force u32)laddr->s6_addr32[3];
-	const u32 fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
+	static u32 inet6_ehash_secret __read_mostly;
+	static u32 ipv6_hash_secret __read_mostly;
+
+	u32 lhash, fhash;
+
+	net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
+	net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
+
+	lhash = (__force u32)laddr->s6_addr32[3];
+	fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
+
 	return __inet6_ehashfn(lhash, lport, fhash, fport,
-			       inet_ehash_secret + net_hash_mix(net));
+			       inet6_ehash_secret + net_hash_mix(net));
 }
 
 static int inet6_sk_ehashfn(const struct sock *sk)
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 324bd36..44fc4e3 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -59,10 +59,21 @@ static unsigned int udp6_ehashfn(struct net *net,
 				  const struct in6_addr *faddr,
 				  const __be16 fport)
 {
-	const u32 lhash = (__force u32)laddr->s6_addr32[3];
-	const u32 fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
+	static u32 udp6_ehash_secret __read_mostly;
+	static u32 udp_ipv6_hash_secret __read_mostly;
+
+	u32 lhash, fhash;
+
+	net_get_random_once(&udp6_ehash_secret,
+			    sizeof(udp6_ehash_secret));
+	net_get_random_once(&udp_ipv6_hash_secret,
+			    sizeof(udp_ipv6_hash_secret));
+
+	lhash = (__force u32)laddr->s6_addr32[3];
+	fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
+
 	return __inet6_ehashfn(lhash, lport, fhash, fport,
-			       inet_ehash_secret + net_hash_mix(net));
+			       udp_ipv6_hash_secret + net_hash_mix(net));
 }
 
 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
-- 
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