From ddbe503203855939946430e39bae58de11b70b69 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Jul 2012 08:11:12 +0000 Subject: [PATCH] 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 Reported-by: Andrew McGregor Cc: Dave Taht Cc: Tom Herbert Cc: David Laight Cc: Joe Perches Signed-off-by: David S. Miller --- include/net/addrconf.h | 3 ++- include/net/ipv6.h | 13 +++++++++++++ net/core/flow_dissector.c | 5 +++-- net/ipv4/tcp_metrics.c | 15 +++------------ net/ipv6/addrconf.c | 21 ++++++++------------- net/ipv6/ip6_tunnel.c | 20 ++++++++++++-------- net/sunrpc/svcauth_unix.c | 22 ++++------------------ 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 #include -#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 #include #include +#include #include #include #include @@ -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 #include #include +#include #include #include @@ -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 #include #include +#include #include #include @@ -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); -- 2.20.1