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authorEric Dumazet <edumazet@google.com>2012-07-18 08:11:12 +0000
committerDavid S. Miller <davem@davemloft.net>2012-07-18 11:28:46 -0700
commitddbe503203855939946430e39bae58de11b70b69 (patch)
tree1605a8d3b14a92819eb8ed47ae5a84c1b66e12f8
parentdc9059512c09d09b99de6cd3a8bc842507934cbb (diff)
ipv6: add ipv6_addr_hash() helper
Introduce ipv6_addr_hash() helper doing a XOR on all bits of an IPv6 address, with an optimized x86_64 version. Use it in flow dissector, as suggested by Andrew McGregor, to reduce hash collision probabilities in fq_codel (and other users of flow dissector) Use it in ip6_tunnel.c and use more bit shuffling, as suggested by David Laight, as existing hash was ignoring most of them. Use it in sunrpc and use more bit shuffling, using hash_32(). Use it in net/ipv6/addrconf.c, using hash_32() as well. As a cleanup, use it in net/ipv4/tcp_metrics.c Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Andrew McGregor <andrewmcgr@gmail.com> Cc: Dave Taht <dave.taht@gmail.com> Cc: Tom Herbert <therbert@google.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/addrconf.h3
-rw-r--r--include/net/ipv6.h13
-rw-r--r--net/core/flow_dissector.c5
-rw-r--r--net/ipv4/tcp_metrics.c15
-rw-r--r--net/ipv6/addrconf.c21
-rw-r--r--net/ipv6/ip6_tunnel.c20
-rw-r--r--net/sunrpc/svcauth_unix.c22
7 files changed, 45 insertions, 54 deletions
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index f2b801c4b55..089a09d001d 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -46,7 +46,8 @@ struct prefix_info {
#include <net/if_inet6.h>
#include <net/ipv6.h>
-#define IN6_ADDR_HSIZE 16
+#define IN6_ADDR_HSIZE_SHIFT 4
+#define IN6_ADDR_HSIZE (1 << IN6_ADDR_HSIZE_SHIFT)
extern int addrconf_init(void);
extern void addrconf_cleanup(void);
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index f695f39e892..01c34b363a3 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -419,6 +419,19 @@ static inline bool ipv6_addr_any(const struct in6_addr *a)
#endif
}
+static inline u32 ipv6_addr_hash(const struct in6_addr *a)
+{
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
+ const unsigned long *ul = (const unsigned long *)a;
+ unsigned long x = ul[0] ^ ul[1];
+
+ return (u32)(x ^ (x >> 32));
+#else
+ return (__force u32)(a->s6_addr32[0] ^ a->s6_addr32[1] ^
+ a->s6_addr32[2] ^ a->s6_addr32[3]);
+#endif
+}
+
static inline bool ipv6_addr_loopback(const struct in6_addr *a)
{
return (a->s6_addr32[0] | a->s6_addr32[1] |
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index a225089df5b..466820b6e34 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -4,6 +4,7 @@
#include <linux/ipv6.h>
#include <linux/if_vlan.h>
#include <net/ip.h>
+#include <net/ipv6.h>
#include <linux/if_tunnel.h>
#include <linux/if_pppox.h>
#include <linux/ppp_defs.h>
@@ -55,8 +56,8 @@ ipv6:
return false;
ip_proto = iph->nexthdr;
- flow->src = iph->saddr.s6_addr32[3];
- flow->dst = iph->daddr.s6_addr32[3];
+ flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
+ flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
nhoff += sizeof(struct ipv6hdr);
break;
}
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 5a38a2d5a95..1a115b66579 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -211,10 +211,7 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
break;
case AF_INET6:
*(struct in6_addr *)addr.addr.a6 = inet6_rsk(req)->rmt_addr;
- hash = ((__force unsigned int) addr.addr.a6[0] ^
- (__force unsigned int) addr.addr.a6[1] ^
- (__force unsigned int) addr.addr.a6[2] ^
- (__force unsigned int) addr.addr.a6[3]);
+ hash = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr);
break;
default:
return NULL;
@@ -251,10 +248,7 @@ static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock
case AF_INET6:
tw6 = inet6_twsk((struct sock *)tw);
*(struct in6_addr *)addr.addr.a6 = tw6->tw_v6_daddr;
- hash = ((__force unsigned int) addr.addr.a6[0] ^
- (__force unsigned int) addr.addr.a6[1] ^
- (__force unsigned int) addr.addr.a6[2] ^
- (__force unsigned int) addr.addr.a6[3]);
+ hash = ipv6_addr_hash(&tw6->tw_v6_daddr);
break;
default:
return NULL;
@@ -291,10 +285,7 @@ static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
break;
case AF_INET6:
*(struct in6_addr *)addr.addr.a6 = inet6_sk(sk)->daddr;
- hash = ((__force unsigned int) addr.addr.a6[0] ^
- (__force unsigned int) addr.addr.a6[1] ^
- (__force unsigned int) addr.addr.a6[2] ^
- (__force unsigned int) addr.addr.a6[3]);
+ hash = ipv6_addr_hash(&inet6_sk(sk)->daddr);
break;
default:
return NULL;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 8f6411c9718..79181819a24 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -63,6 +63,7 @@
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/string.h>
+#include <linux/hash.h>
#include <net/net_namespace.h>
#include <net/sock.h>
@@ -579,15 +580,9 @@ ipv6_link_dev_addr(struct inet6_dev *idev, struct inet6_ifaddr *ifp)
list_add_tail(&ifp->if_list, p);
}
-static u32 ipv6_addr_hash(const struct in6_addr *addr)
+static u32 inet6_addr_hash(const struct in6_addr *addr)
{
- /*
- * We perform the hash function over the last 64 bits of the address
- * This will include the IEEE address token on links that support it.
- */
- return jhash_2words((__force u32)addr->s6_addr32[2],
- (__force u32)addr->s6_addr32[3], 0)
- & (IN6_ADDR_HSIZE - 1);
+ return hash_32(ipv6_addr_hash(addr), IN6_ADDR_HSIZE_SHIFT);
}
/* On success it returns ifp with increased reference count */
@@ -662,7 +657,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
in6_ifa_hold(ifa);
/* Add to big hash table */
- hash = ipv6_addr_hash(addr);
+ hash = inet6_addr_hash(addr);
hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
spin_unlock(&addrconf_hash_lock);
@@ -1270,7 +1265,7 @@ int ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
{
struct inet6_ifaddr *ifp;
struct hlist_node *node;
- unsigned int hash = ipv6_addr_hash(addr);
+ unsigned int hash = inet6_addr_hash(addr);
rcu_read_lock_bh();
hlist_for_each_entry_rcu(ifp, node, &inet6_addr_lst[hash], addr_lst) {
@@ -1293,7 +1288,7 @@ EXPORT_SYMBOL(ipv6_chk_addr);
static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
struct net_device *dev)
{
- unsigned int hash = ipv6_addr_hash(addr);
+ unsigned int hash = inet6_addr_hash(addr);
struct inet6_ifaddr *ifp;
struct hlist_node *node;
@@ -1336,7 +1331,7 @@ struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *add
struct net_device *dev, int strict)
{
struct inet6_ifaddr *ifp, *result = NULL;
- unsigned int hash = ipv6_addr_hash(addr);
+ unsigned int hash = inet6_addr_hash(addr);
struct hlist_node *node;
rcu_read_lock_bh();
@@ -3223,7 +3218,7 @@ int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr)
int ret = 0;
struct inet6_ifaddr *ifp = NULL;
struct hlist_node *n;
- unsigned int hash = ipv6_addr_hash(addr);
+ unsigned int hash = inet6_addr_hash(addr);
rcu_read_lock_bh();
hlist_for_each_entry_rcu_bh(ifp, n, &inet6_addr_lst[hash], addr_lst) {
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index db328466796..9a1d5fe6aef 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -40,6 +40,7 @@
#include <linux/rtnetlink.h>
#include <linux/netfilter_ipv6.h>
#include <linux/slab.h>
+#include <linux/hash.h>
#include <asm/uaccess.h>
#include <linux/atomic.h>
@@ -70,11 +71,15 @@ MODULE_ALIAS_NETDEV("ip6tnl0");
#define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK)
#define IPV6_TCLASS_SHIFT 20
-#define HASH_SIZE 32
+#define HASH_SIZE_SHIFT 5
+#define HASH_SIZE (1 << HASH_SIZE_SHIFT)
-#define HASH(addr) ((__force u32)((addr)->s6_addr32[0] ^ (addr)->s6_addr32[1] ^ \
- (addr)->s6_addr32[2] ^ (addr)->s6_addr32[3]) & \
- (HASH_SIZE - 1))
+static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
+{
+ u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);
+
+ return hash_32(hash, HASH_SIZE_SHIFT);
+}
static int ip6_tnl_dev_init(struct net_device *dev);
static void ip6_tnl_dev_setup(struct net_device *dev);
@@ -166,12 +171,11 @@ static inline void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
static struct ip6_tnl *
ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local)
{
- unsigned int h0 = HASH(remote);
- unsigned int h1 = HASH(local);
+ unsigned int hash = HASH(remote, local);
struct ip6_tnl *t;
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
- for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[h0 ^ h1]) {
+ for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
if (ipv6_addr_equal(local, &t->parms.laddr) &&
ipv6_addr_equal(remote, &t->parms.raddr) &&
(t->dev->flags & IFF_UP))
@@ -205,7 +209,7 @@ ip6_tnl_bucket(struct ip6_tnl_net *ip6n, const struct ip6_tnl_parm *p)
if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
prio = 1;
- h = HASH(remote) ^ HASH(local);
+ h = HASH(remote, local);
}
return &ip6n->tnls[prio][h];
}
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 2777fa89664..4d012920373 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -104,23 +104,9 @@ static void ip_map_put(struct kref *kref)
kfree(im);
}
-#if IP_HASHBITS == 8
-/* hash_long on a 64 bit machine is currently REALLY BAD for
- * IP addresses in reverse-endian (i.e. on a little-endian machine).
- * So use a trivial but reliable hash instead
- */
-static inline int hash_ip(__be32 ip)
-{
- int hash = (__force u32)ip ^ ((__force u32)ip>>16);
- return (hash ^ (hash>>8)) & 0xff;
-}
-#endif
-static inline int hash_ip6(struct in6_addr ip)
+static inline int hash_ip6(const struct in6_addr *ip)
{
- return (hash_ip(ip.s6_addr32[0]) ^
- hash_ip(ip.s6_addr32[1]) ^
- hash_ip(ip.s6_addr32[2]) ^
- hash_ip(ip.s6_addr32[3]));
+ return hash_32(ipv6_addr_hash(ip), IP_HASHBITS);
}
static int ip_map_match(struct cache_head *corig, struct cache_head *cnew)
{
@@ -301,7 +287,7 @@ static struct ip_map *__ip_map_lookup(struct cache_detail *cd, char *class,
ip.m_addr = *addr;
ch = sunrpc_cache_lookup(cd, &ip.h,
hash_str(class, IP_HASHBITS) ^
- hash_ip6(*addr));
+ hash_ip6(addr));
if (ch)
return container_of(ch, struct ip_map, h);
@@ -331,7 +317,7 @@ static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm,
ip.h.expiry_time = expiry;
ch = sunrpc_cache_update(cd, &ip.h, &ipm->h,
hash_str(ipm->m_class, IP_HASHBITS) ^
- hash_ip6(ipm->m_addr));
+ hash_ip6(&ipm->m_addr));
if (!ch)
return -ENOMEM;
cache_put(ch, cd);