Commit f452be49 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

af_unix: Add helpers to calculate hashes. 



This patch adds three helper functions that calculate hashes for unbound
sockets and bound sockets with BSD/abstract addresses.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5ce7ab49

net/unix/af_unix.c

+35 −29
Original line number Diff line number Diff line
@@ -123,15 +123,38 @@ DEFINE_SPINLOCK(unix_table_lock); 
EXPORT_SYMBOL_GPL(unix_table_lock);

static atomic_long_t unix_nr_socks;



/* SMP locking strategy:

 *    hash table is protected with spinlock unix_table_lock

 *    each socket state is protected by separate spin lock.

 */



static struct hlist_head *unix_sockets_unbound(void *addr)

static unsigned int unix_unbound_hash(struct sock *sk)

{

	unsigned long hash = (unsigned long)addr;

	unsigned long hash = (unsigned long)sk;



	hash ^= hash >> 16;

	hash ^= hash >> 8;

	hash %= UNIX_HASH_SIZE;

	return &unix_socket_table[UNIX_HASH_SIZE + hash];

	hash ^= sk->sk_type;



	return UNIX_HASH_SIZE + (hash & (UNIX_HASH_SIZE - 1));

}



static unsigned int unix_bsd_hash(struct inode *i)

{

	return i->i_ino & (UNIX_HASH_SIZE - 1);

}



static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr,

				       int addr_len, int type)

{

	__wsum csum = csum_partial(sunaddr, addr_len, 0);

	unsigned int hash;



	hash = (__force unsigned int)csum_fold(csum);

	hash ^= hash >> 8;

	hash ^= type;



	return hash & (UNIX_HASH_SIZE - 1);

}



#ifdef CONFIG_SECURITY_NETWORK
@@ -162,20 +185,6 @@ static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb) 
}

#endif /* CONFIG_SECURITY_NETWORK */



/*

 *  SMP locking strategy:

 *    hash table is protected with spinlock unix_table_lock

 *    each socket state is protected by separate spin lock.

 */



static inline unsigned int unix_hash_fold(__wsum n)

{

	unsigned int hash = (__force unsigned int)csum_fold(n);



	hash ^= hash>>8;

	return hash&(UNIX_HASH_SIZE-1);

}



#define unix_peer(sk) (unix_sk(sk)->peer)



static inline int unix_our_peer(struct sock *sk, struct sock *osk)
@@ -334,11 +343,11 @@ static inline struct sock *unix_find_socket_byname(struct net *net, 


static struct sock *unix_find_socket_byinode(struct inode *i)

{

	unsigned int hash = unix_bsd_hash(i);

	struct sock *s;



	spin_lock(&unix_table_lock);

	sk_for_each(s,

		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {

	sk_for_each(s, &unix_socket_table[hash]) {

		struct dentry *dentry = unix_sk(s)->path.dentry;



		if (dentry && d_backing_inode(dentry) == i) {
@@ -899,7 +908,7 @@ static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, 
	init_waitqueue_head(&u->peer_wait);

	init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);

	memset(&u->scm_stat, 0, sizeof(struct scm_stat));

	unix_insert_socket(unix_sockets_unbound(sk), sk);

	unix_insert_socket(&unix_socket_table[unix_unbound_hash(sk)], sk);



	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
@@ -1010,11 +1019,11 @@ static struct sock *unix_find_abstract(struct net *net, 
				       struct sockaddr_un *sunaddr,

				       int addr_len, int type)

{

	unsigned int hash = unix_hash_fold(csum_partial(sunaddr, addr_len, 0));

	unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type);

	struct dentry *dentry;

	struct sock *sk;



	sk = unix_find_socket_byname(net, sunaddr, addr_len, type ^ hash);

	sk = unix_find_socket_byname(net, sunaddr, addr_len, hash);

	if (!sk)

		return ERR_PTR(-ECONNREFUSED);
@@ -1066,8 +1075,7 @@ static int unix_autobind(struct sock *sk) 
retry:

	addr->len = sprintf(addr->name->sun_path + 1, "%05x", ordernum) +

		offsetof(struct sockaddr_un, sun_path) + 1;

	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));

	addr->hash ^= sk->sk_type;

	addr->hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);



	spin_lock(&unix_table_lock);

	ordernum = (ordernum+1)&0xFFFFF;
@@ -1144,7 +1152,7 @@ static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr, 
		goto out_unlock;



	addr->hash = UNIX_HASH_SIZE;

	hash = d_backing_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1);

	hash = unix_bsd_hash(d_backing_inode(dentry));

	spin_lock(&unix_table_lock);

	u->path.mnt = mntget(parent.mnt);

	u->path.dentry = dget(dentry);
@@ -1187,9 +1195,7 @@ static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr, 
		goto out_mutex;

	}



	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));

	addr->hash ^= sk->sk_type;



	addr->hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);

	spin_lock(&unix_table_lock);



	if (__unix_find_socket_byname(sock_net(sk), addr->name, addr->len,