/*
 * Copyright (c) 1982, 1986, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)unpcb.h     8.1 (Berkeley) 6/2/93
 * $FreeBSD: src/sys/sys/unpcb.h,v 1.9.2.1 2002/03/09 05:22:23 dd Exp $
 * $DragonFly: src/sys/sys/unpcb.h,v 1.5 2008/05/27 05:25:36 dillon Exp $
 */

#ifndef _SYS_UNPCB_H_
#define _SYS_UNPCB_H_

#include <sys/queue.h>
#include <sys/ucred.h>

/*
 * Protocol control block for an active
 * instance of a UNIX internal protocol.
 *
 * A socket may be associated with an vnode in the
 * file system.  If so, the unp_vnode pointer holds
 * a reference count to this vnode, which should be irele'd
 * when the socket goes away.
 *
 * A socket may be connected to another socket, in which
 * case the control block of the socket to which it is connected
 * is given by unp_conn.
 *
 * A socket may be referenced by a number of sockets (e.g. several
 * sockets may be connected to a datagram socket.)  These sockets
 * are in a linked list starting with unp_refs, linked through
 * unp_nextref and null-terminated.  Note that a socket may be referenced
 * by a number of other sockets and may also reference a socket (not
 * necessarily one which is referencing it).  This generates
 * the need for unp_refs and unp_nextref to be separate fields.
 *
 * Stream sockets keep copies of receive sockbuf sb_cc and sb_mbcnt
 * so that changes in the sockbuf may be computed to modify
 * back pressure on the sender accordingly.
 */
typedef u_quad_t        unp_gen_t;
LIST_HEAD(unp_head, unpcb);

struct  unpcb {
        struct socket   *unp_socket;    /* pointer back to socket */
        struct unpcb    *unp_conn;      /* control block of connected socket */
        int             unp_flags;      /* flags */
        int             unp_refcnt;     /* referece count */
        struct unp_head unp_refs;       /* referencing socket linked list */
        LIST_ENTRY(unpcb) unp_reflink;  /* link in unp_refs list */
        struct sockaddr_un *unp_addr;   /* bound address of socket */
        struct xucred   unp_peercred;   /* peer credentials, if applicable */
        int             unp_msgcount;   /* # of cmsgs this unp are in */
        int             unp_gcflags;    /* flags reserved for unp GC to use */
        struct file     *unp_fp;        /* cooresponding fp if unp is in cmsg */
        long            unp_unused01;
        struct vnode    *unp_vnode;     /* if associated with file */
        struct vnode    *unp_rvnode;    /* root vp for creating process */
        TAILQ_ENTRY(unpcb) unp_link;    /* glue on list of all PCBs */
        unp_gen_t       unp_gencnt;     /* generation count of this instance */
};

/*
 * Flags in unp_flags.
 *
 * UNP_HAVEPC - indicates that the unp_peercred member is filled in
 * and is really the credentials of the connected peer.  This is used
 * to determine whether the contents should be sent to the user or
 * not.
 *
 * UNP_HAVEPCCACHED - indicates that the unp_peercred member is filled
 * in, but does *not* contain the credentials of the connected peer
 * (there may not even be a peer).  This is set in unp_listen() when
 * it fills in unp_peercred for later consumption by unp_connect().
 *
 * UNP_PRIVATE{1,2,3,4} - Implementation private.
 */
#define UNP_HAVEPC                      0x001
#define UNP_HAVEPCCACHED                0x002
#define UNP_PRIVATE1                    0x004
#define UNP_PRIVATE2                    0x008
#define UNP_PRIVATE3                    0x010
#define UNP_PRIVATE4                    0x020

/* Hack alert -- this structure depends on <sys/socketvar.h>. */
#ifdef  _SYS_SOCKETVAR_H_
struct  xunpcb {
        size_t  xu_len;                 /* length of this structure */
        struct  unpcb *xu_unpp;         /* to help netstat, fstat */
        struct  unpcb xu_unp;           /* our information */
        union {
                struct  sockaddr_un xuu_addr;   /* our bound address */
                char    xu_dummy1[256];
        } xu_au;
#define xu_addr xu_au.xuu_addr
        union {
                struct  sockaddr_un xuu_caddr; /* their bound address */
                char    xu_dummy2[256];
        } xu_cau;
#define xu_caddr xu_cau.xuu_caddr
        struct  xsocket xu_socket;
        u_quad_t        xu_alignment_hack;
};
#endif /* _SYS_SOCKETVAR_H_ */

#endif /* _SYS_UNPCB_H_ */