linux/include/net/af_unix.h

#ifndef __LINUX_NET_AFUNIX_H
#define __LINUX_NET_AFUNIX_H

#include <linux/config.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <net/sock.h>

extern void unix_inflight(struct file *fp);
extern void unix_notinflight(struct file *fp);
extern void unix_gc(void);

#define UNIX_HASH_SIZE	256

extern struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
extern spinlock_t unix_table_lock;

extern atomic_t unix_tot_inflight;

static inline struct sock *first_unix_socket(int *i)
{
	for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
		if (!hlist_empty(&unix_socket_table[*i]))
			return __sk_head(&unix_socket_table[*i]);
	}
	return NULL;
}

static inline struct sock *next_unix_socket(int *i, struct sock *s)
{
	struct sock *next = sk_next(s);
	/* More in this chain? */
	if (next)
		return next;
	/* Look for next non-empty chain. */
	for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
		if (!hlist_empty(&unix_socket_table[*i]))
			return __sk_head(&unix_socket_table[*i]);
	}
	return NULL;
}

#define forall_unix_sockets(i, s) \
	for (s = first_unix_socket(&(i)); s; s = next_unix_socket(&(i),(s)))

struct unix_address {
	atomic_t	refcnt;
	int		len;
	unsigned	hash;
	struct sockaddr_un name[0];
};

struct unix_skb_parms {
	struct ucred		creds;		/* Skb credentials	*/
	struct scm_fp_list	*fp;		/* Passed files		*/
};

#define UNIXCB(skb) 	(*(struct unix_skb_parms*)&((skb)->cb))
#define UNIXCREDS(skb)	(&UNIXCB((skb)).creds)

#define unix_state_rlock(s)	spin_lock(&unix_sk(s)->lock)
#define unix_state_runlock(s)	spin_unlock(&unix_sk(s)->lock)
#define unix_state_wlock(s)	spin_lock(&unix_sk(s)->lock)
#define unix_state_wunlock(s)	spin_unlock(&unix_sk(s)->lock)

#ifdef __KERNEL__
/* The AF_UNIX socket */
struct unix_sock {
	/* WARNING: sk has to be the first member */
	struct sock		sk;
        struct unix_address     *addr;
        struct dentry		*dentry;
        struct vfsmount		*mnt;
        struct semaphore        readsem;
        struct sock		*peer;
        struct sock		*other;
        struct sock		*gc_tree;
        atomic_t                inflight;
        spinlock_t		lock;
        wait_queue_head_t       peer_wait;
};
#define unix_sk(__sk) ((struct unix_sock *)__sk)

#ifdef CONFIG_SYSCTL
extern int sysctl_unix_max_dgram_qlen;
extern void unix_sysctl_register(void);
extern void unix_sysctl_unregister(void);
#else
static inline void unix_sysctl_register(void) {}
static inline void unix_sysctl_unregister(void) {}
#endif
#endif
#endif