4.3BSD - /usr/src/sys/h/unpcb.h

   1: /*
   2:  * Copyright (c) 1982, 1986 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  *
   6:  *	@(#)unpcb.h	7.1 (Berkeley) 6/4/86
   7:  */
   8: 
   9: /*
  10:  * Protocol control block for an active
  11:  * instance of a UNIX internal protocol.
  12:  *
  13:  * A socket may be associated with an inode in the
  14:  * file system.  If so, the unp_inode pointer holds
  15:  * a reference count to this inode, which should be irele'd
  16:  * when the socket goes away.
  17:  *
  18:  * A socket may be connected to another socket, in which
  19:  * case the control block of the socket to which it is connected
  20:  * is given by unp_conn.
  21:  *
  22:  * A socket may be referenced by a number of sockets (e.g. several
  23:  * sockets may be connected to a datagram socket.)  These sockets
  24:  * are in a linked list starting with unp_refs, linked through
  25:  * unp_nextref and null-terminated.  Note that a socket may be referenced
  26:  * by a number of other sockets and may also reference a socket (not
  27:  * necessarily one which is referencing it).  This generates
  28:  * the need for unp_refs and unp_nextref to be separate fields.
  29:  *
  30:  * Stream sockets keep copies of receive sockbuf sb_cc and sb_mbcnt
  31:  * so that changes in the sockbuf may be computed to modify
  32:  * back pressure on the sender accordingly.
  33:  */
  34: struct  unpcb {
  35:     struct  socket *unp_socket; /* pointer back to socket */
  36:     struct  inode *unp_inode;   /* if associated with file */
  37:     ino_t   unp_ino;        /* fake inode number */
  38:     struct  unpcb *unp_conn;    /* control block of connected socket */
  39:     struct  unpcb *unp_refs;    /* referencing socket linked list */
  40:     struct  unpcb *unp_nextref; /* link in unp_refs list */
  41:     struct  mbuf *unp_addr;     /* bound address of socket */
  42:     int unp_cc;         /* copy of rcv.sb_cc */
  43:     int unp_mbcnt;      /* copy of rcv.sb_mbcnt */
  44: };
  45: 
  46: #define sotounpcb(so)   ((struct unpcb *)((so)->so_pcb))

Defined struct's

Defined macros

Usage of this include