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Commit 512615b6 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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udp: secondary hash on (local port, local address) 



Extends udp_table to contain a secondary hash table.

socket anchor for this second hash is free, because UDP
doesnt use skc_bind_node : We define an union to hold
both skc_bind_node & a new hlist_nulls_node udp_portaddr_node

udp_lib_get_port() inserts sockets into second hash chain
(additional cost of one atomic op)

udp_lib_unhash() deletes socket from second hash chain
(additional cost of one atomic op)

Note : No spinlock lockdep annotation is needed, because
lock for the secondary hash chain is always get after
lock for primary hash chain.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d4cada4a

include/linux/udp.h

+1 −0
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ struct udp_sock { 
	struct inet_sock inet;

#define udp_port_hash		inet.sk.__sk_common.skc_u16hashes[0]

#define udp_portaddr_hash	inet.sk.__sk_common.skc_u16hashes[1]

#define udp_portaddr_node	inet.sk.__sk_common.skc_portaddr_node

	int		 pending;	/* Any pending frames ? */

	unsigned int	 corkflag;	/* Cork is required */

  	__u16		 encap_type;	/* Is this an Encapsulation socket? */

include/net/sock.h

+6 −2
Original line number Diff line number Diff line
@@ -105,7 +105,7 @@ struct net; 
/**

 *	struct sock_common - minimal network layer representation of sockets

 *	@skc_node: main hash linkage for various protocol lookup tables

 *	@skc_nulls_node: main hash linkage for UDP/UDP-Lite protocol

 *	@skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol

 *	@skc_refcnt: reference count

 *	@skc_tx_queue_mapping: tx queue number for this connection

 *	@skc_hash: hash value used with various protocol lookup tables
@@ -115,6 +115,7 @@ struct net; 
 *	@skc_reuse: %SO_REUSEADDR setting

 *	@skc_bound_dev_if: bound device index if != 0

 *	@skc_bind_node: bind hash linkage for various protocol lookup tables

 *	@skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol

 *	@skc_prot: protocol handlers inside a network family

 *	@skc_net: reference to the network namespace of this socket

 *
@@ -140,7 +141,10 @@ struct sock_common { 
	volatile unsigned char	skc_state;

	unsigned char		skc_reuse;

	int			skc_bound_dev_if;

	union {

		struct hlist_node	skc_bind_node;

		struct hlist_nulls_node skc_portaddr_node;

	};

	struct proto		*skc_prot;

#ifdef CONFIG_NET_NS

	struct net	 	*skc_net;

include/net/udp.h

+20 −2
Original line number Diff line number Diff line
@@ -63,8 +63,17 @@ struct udp_hslot { 
	spinlock_t		lock;

} __attribute__((aligned(2 * sizeof(long))));



/**

 *	struct udp_table - UDP table

 *

 *	@hash:	hash table, sockets are hashed on (local port)

 *	@hash2:	hash table, sockets are hashed on (local port, local address)

 *	@mask:	number of slots in hash tables, minus 1

 *	@log:	log2(number of slots in hash table)

 */

struct udp_table {

	struct udp_hslot	*hash;

	struct udp_hslot	*hash2;

	unsigned int		mask;

	unsigned int		log;

};
@@ -75,6 +84,15 @@ static inline struct udp_hslot *udp_hashslot(struct udp_table *table, 
{

	return &table->hash[udp_hashfn(net, num, table->mask)];

}

/*

 * For secondary hash, net_hash_mix() is performed before calling

 * udp_hashslot2(), this explains difference with udp_hashslot()

 */

static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,

					      unsigned int hash)

{

	return &table->hash2[hash & table->mask];

}



/* Note: this must match 'valbool' in sock_setsockopt */

#define UDP_CSUM_NOXMIT		1

net/ipv4/udp.c

+26 −5
Original line number Diff line number Diff line
@@ -163,7 +163,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum, 
		       int (*saddr_comp)(const struct sock *sk1,

					 const struct sock *sk2))

{

	struct udp_hslot *hslot;

	struct udp_hslot *hslot, *hslot2;

	struct udp_table *udptable = sk->sk_prot->h.udp_table;

	int    error = 1;

	struct net *net = sock_net(sk);
@@ -222,6 +222,13 @@ found: 
		sk_nulls_add_node_rcu(sk, &hslot->head);

		hslot->count++;

		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);



		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);

		spin_lock(&hslot2->lock);

		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,

					 &hslot2->head);

		hslot2->count++;

		spin_unlock(&hslot2->lock);

	}

	error = 0;

fail_unlock:
@@ -1062,14 +1069,22 @@ void udp_lib_unhash(struct sock *sk) 
{

	if (sk_hashed(sk)) {

		struct udp_table *udptable = sk->sk_prot->h.udp_table;

		struct udp_hslot *hslot = udp_hashslot(udptable, sock_net(sk),

		struct udp_hslot *hslot, *hslot2;



		hslot  = udp_hashslot(udptable, sock_net(sk),

				      udp_sk(sk)->udp_port_hash);

		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);



		spin_lock_bh(&hslot->lock);

		if (sk_nulls_del_node_init_rcu(sk)) {

			hslot->count--;

			inet_sk(sk)->inet_num = 0;

			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);



			spin_lock(&hslot2->lock);

			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);

			hslot2->count--;

			spin_unlock(&hslot2->lock);

		}

		spin_unlock_bh(&hslot->lock);

	}
@@ -1857,7 +1872,7 @@ void __init udp_table_init(struct udp_table *table, const char *name) 


	if (!CONFIG_BASE_SMALL)

		table->hash = alloc_large_system_hash(name,

			sizeof(struct udp_hslot),

			2 * sizeof(struct udp_hslot),

			uhash_entries,

			21, /* one slot per 2 MB */

			0,
@@ -1869,17 +1884,23 @@ void __init udp_table_init(struct udp_table *table, const char *name) 
	 */

	if (CONFIG_BASE_SMALL || table->mask < UDP_HTABLE_SIZE_MIN - 1) {

		table->hash = kmalloc(UDP_HTABLE_SIZE_MIN *

				      sizeof(struct udp_hslot), GFP_KERNEL);

				      2 * sizeof(struct udp_hslot), GFP_KERNEL);

		if (!table->hash)

			panic(name);

		table->log = ilog2(UDP_HTABLE_SIZE_MIN);

		table->mask = UDP_HTABLE_SIZE_MIN - 1;

	}

	table->hash2 = table->hash + (table->mask + 1);

	for (i = 0; i <= table->mask; i++) {

		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);

		table->hash[i].count = 0;

		spin_lock_init(&table->hash[i].lock);

	}

	for (i = 0; i <= table->mask; i++) {

		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);

		table->hash2[i].count = 0;

		spin_lock_init(&table->hash2[i].lock);

	}

}



void __init udp_init(void)