udp: split sk_hash into two u16 hashes
Union sk_hash with two u16 hashes for udp (no extra memory taken)
One 16 bits hash on (local port) value (the previous udp 'hash')
One 16 bits hash on (local address, local port) values, initialized
but not yet used. This second hash is using jenkin hash for better
distribution.
Because the 'port' is xored later, a partial hash is performed
on local address + net_hash_mix(net)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ffc8376..af72de1 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -138,13 +138,14 @@
sk_nulls_for_each(sk2, node, &hslot->head)
if (net_eq(sock_net(sk2), net) &&
sk2 != sk &&
- (bitmap || sk2->sk_hash == num) &&
+ (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
(!sk2->sk_reuse || !sk->sk_reuse) &&
(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
(*saddr_comp)(sk, sk2)) {
if (bitmap)
- __set_bit(sk2->sk_hash >> log, bitmap);
+ __set_bit(udp_sk(sk2)->udp_port_hash >> log,
+ bitmap);
else
return 1;
}
@@ -215,7 +216,8 @@
}
found:
inet_sk(sk)->inet_num = snum;
- sk->sk_hash = snum;
+ udp_sk(sk)->udp_port_hash = snum;
+ udp_sk(sk)->udp_portaddr_hash ^= snum;
if (sk_unhashed(sk)) {
sk_nulls_add_node_rcu(sk, &hslot->head);
hslot->count++;
@@ -238,8 +240,19 @@
inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
}
+static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
+ unsigned int port)
+{
+ return jhash_1word(saddr, net_hash_mix(net)) ^ port;
+}
+
int udp_v4_get_port(struct sock *sk, unsigned short snum)
{
+ /* precompute partial secondary hash */
+ udp_sk(sk)->udp_portaddr_hash =
+ udp4_portaddr_hash(sock_net(sk),
+ inet_sk(sk)->inet_rcv_saddr,
+ 0);
return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal);
}
@@ -249,7 +262,7 @@
{
int score = -1;
- if (net_eq(sock_net(sk), net) && sk->sk_hash == hnum &&
+ if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
!ipv6_only_sock(sk)) {
struct inet_sock *inet = inet_sk(sk);
@@ -360,7 +373,7 @@
struct inet_sock *inet = inet_sk(s);
if (!net_eq(sock_net(s), net) ||
- s->sk_hash != hnum ||
+ udp_sk(s)->udp_port_hash != hnum ||
(inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
(inet->inet_dport != rmt_port && inet->inet_dport) ||
(inet->inet_rcv_saddr &&
@@ -1050,7 +1063,7 @@
if (sk_hashed(sk)) {
struct udp_table *udptable = sk->sk_prot->h.udp_table;
struct udp_hslot *hslot = udp_hashslot(udptable, sock_net(sk),
- sk->sk_hash);
+ udp_sk(sk)->udp_port_hash);
spin_lock_bh(&hslot->lock);
if (sk_nulls_del_node_init_rcu(sk)) {