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Annotation of 43BSDTahoe/sys/h/unpcb.h, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1982, 1986 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that the above copyright notice and this paragraph are
                      7:  * duplicated in all such forms and that any documentation,
                      8:  * advertising materials, and other materials related to such
                      9:  * distribution and use acknowledge that the software was developed
                     10:  * by the University of California, Berkeley.  The name of the
                     11:  * University may not be used to endorse or promote products derived
                     12:  * from this software without specific prior written permission.
                     13:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     14:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     15:  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     16:  *
                     17:  *     @(#)unpcb.h     7.3 (Berkeley) 6/27/88
                     18:  */
                     19: 
                     20: /*
                     21:  * Protocol control block for an active
                     22:  * instance of a UNIX internal protocol.
                     23:  *
                     24:  * A socket may be associated with an inode in the
                     25:  * file system.  If so, the unp_inode pointer holds
                     26:  * a reference count to this inode, which should be irele'd
                     27:  * when the socket goes away.
                     28:  *
                     29:  * A socket may be connected to another socket, in which
                     30:  * case the control block of the socket to which it is connected
                     31:  * is given by unp_conn.
                     32:  *
                     33:  * A socket may be referenced by a number of sockets (e.g. several
                     34:  * sockets may be connected to a datagram socket.)  These sockets
                     35:  * are in a linked list starting with unp_refs, linked through
                     36:  * unp_nextref and null-terminated.  Note that a socket may be referenced
                     37:  * by a number of other sockets and may also reference a socket (not
                     38:  * necessarily one which is referencing it).  This generates
                     39:  * the need for unp_refs and unp_nextref to be separate fields.
                     40:  *
                     41:  * Stream sockets keep copies of receive sockbuf sb_cc and sb_mbcnt
                     42:  * so that changes in the sockbuf may be computed to modify
                     43:  * back pressure on the sender accordingly.
                     44:  */
                     45: struct unpcb {
                     46:        struct  socket *unp_socket;     /* pointer back to socket */
                     47:        struct  inode *unp_inode;       /* if associated with file */
                     48:        ino_t   unp_ino;                /* fake inode number */
                     49:        struct  unpcb *unp_conn;        /* control block of connected socket */
                     50:        struct  unpcb *unp_refs;        /* referencing socket linked list */
                     51:        struct  unpcb *unp_nextref;     /* link in unp_refs list */
                     52:        struct  mbuf *unp_addr;         /* bound address of socket */
                     53:        int     unp_cc;                 /* copy of rcv.sb_cc */
                     54:        int     unp_mbcnt;              /* copy of rcv.sb_mbcnt */
                     55: };
                     56: 
                     57: #define        sotounpcb(so)   ((struct unpcb *)((so)->so_pcb))

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