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Subject[PATCH net-next v3 7/9] inet: convert inet_ehash_secret and ipv6_hash_secret to net_get_random_once
Date
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>
---
include/net/inet_sock.h | 4 ----
net/ipv4/af_inet.c | 27 ---------------------------
net/ipv4/inet_hashtables.c | 4 ++++
net/ipv4/udp.c | 6 +++++-
net/ipv6/af_inet6.c | 5 -----
net/ipv6/inet6_hashtables.c | 15 ++++++++++++---
net/ipv6/udp.c | 17 ++++++++++++++---
net/rds/connection.c | 12 +++++++++---
8 files changed, 44 insertions(+), 46 deletions(-)

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 7a6c7f8..1833c3f 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -204,10 +204,6 @@ static inline void inet_sk_copy_descendant(struct sock *sk_to,

int inet_sk_rebuild_header(struct sock *sk);

-extern u32 inet_ehash_secret;
-extern u32 ipv6_hash_secret;
-void build_ehash_secret(void);
-
static inline unsigned int __inet_ehashfn(const __be32 laddr,
const __u16 lport,
const __be32 faddr,
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 35913fb..b6bdd82 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -245,29 +245,6 @@ out:
}
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, and to a non nul value
- * ipv6_hash_secret must be set exactly once.
- */
-void build_ehash_secret(void)
-{
- u32 rnd;
-
- do {
- get_random_bytes(&rnd, sizeof(rnd));
- } while (rnd == 0);
-
- if (cmpxchg(&inet_ehash_secret, 0, rnd) == 0)
- get_random_bytes(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
-}
-EXPORT_SYMBOL(build_ehash_secret);
-
/*
* Create an inet socket.
*/
@@ -284,10 +261,6 @@ static int inet_create(struct net *net, struct socket *sock, int protocol,
int try_loading_module = 0;
int err;

- if (unlikely(!inet_ehash_secret))
- if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
- build_ehash_secret();
-
sock->state = SS_UNCONNECTED;

/* Look for the requested type/protocol pair. */
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 18aa668..8b9cf27 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -28,6 +28,10 @@ static unsigned int inet_ehashfn(struct net *net, const __be32 laddr,
const __u16 lport, const __be32 faddr,
const __be16 fport)
{
+ static u32 inet_ehash_secret __read_mostly;
+
+ net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
+
return __inet_ehashfn(laddr, lport, faddr, fport,
inet_ehash_secret + net_hash_mix(net));
}
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index b4437c7..89909dd 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -411,8 +411,12 @@ static unsigned int udp_ehashfn(struct net *net, const __be32 laddr,
const __u16 lport, const __be32 faddr,
const __be16 fport)
{
+ static u32 udp_ehash_secret __read_mostly;
+
+ net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
+
return __inet_ehashfn(laddr, lport, faddr, fport,
- inet_ehash_secret + net_hash_mix(net));
+ udp_ehash_secret + net_hash_mix(net));
}


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)
diff --git a/net/rds/connection.c b/net/rds/connection.c
index 45e2366..378c3a6 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -51,10 +51,16 @@ static struct kmem_cache *rds_conn_slab;

static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
{
+ static u32 rds_hash_secret __read_mostly;
+
+ unsigned long hash;
+
+ net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
+
/* Pass NULL, don't need struct net for hash */
- unsigned long hash = __inet_ehashfn(be32_to_cpu(laddr), 0,
- be32_to_cpu(faddr), 0,
- inet_ehash_secret);
+ hash = __inet_ehashfn(be32_to_cpu(laddr), 0,
+ be32_to_cpu(faddr), 0,
+ rds_hash_secret);
return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
}

--
1.8.3.1


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