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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>
This commit is contained in:
Hannes Frederic Sowa 2013-10-19 21:48:57 +02:00 committed by David S. Miller
parent b23a002fc6
commit 1bbdceef1e
8 changed files with 44 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/inet_sock.h
View File

@ -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,

27
net/ipv4/af_inet.c
View File

@ -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. */

4
net/ipv4/inet_hashtables.c
View File

@ -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));
}

6
net/ipv4/udp.c
View File

@ -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));
}

5
net/ipv6/af_inet6.c
View File

@ -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;

15
net/ipv6/inet6_hashtables.c
View File

@ -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)

17
net/ipv6/udp.c
View File

@ -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)

12
net/rds/connection.c
View File

@ -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];
}