From f452be496a5c8f58b1a67cde79e89b9f1cfde31c Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 24 Nov 2021 11:14:28 +0900 Subject: 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: Kuniyuki Iwashima Signed-off-by: Jakub Kicinski --- net/unix/af_unix.c | 64 +++++++++++++++++++++++++++++------------------------- 1 file changed, 35 insertions(+), 29 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 80752ab9ed97..076d0297450d 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -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, -- cgit v1.2.3-58-ga151