uipc: Fix lockless unp_conn accessing and uipc_detach() race.
[dragonfly.git] / sys / sys / unpcb.h
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1/*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)unpcb.h 8.1 (Berkeley) 6/2/93
34 * $FreeBSD: src/sys/sys/unpcb.h,v 1.9.2.1 2002/03/09 05:22:23 dd Exp $
3a6117bb 35 * $DragonFly: src/sys/sys/unpcb.h,v 1.5 2008/05/27 05:25:36 dillon Exp $
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36 */
37
38#ifndef _SYS_UNPCB_H_
39#define _SYS_UNPCB_H_
40
41#include <sys/queue.h>
42#include <sys/ucred.h>
43
44/*
45 * Protocol control block for an active
46 * instance of a UNIX internal protocol.
47 *
48 * A socket may be associated with an vnode in the
49 * file system. If so, the unp_vnode pointer holds
50 * a reference count to this vnode, which should be irele'd
51 * when the socket goes away.
52 *
53 * A socket may be connected to another socket, in which
54 * case the control block of the socket to which it is connected
55 * is given by unp_conn.
56 *
57 * A socket may be referenced by a number of sockets (e.g. several
58 * sockets may be connected to a datagram socket.) These sockets
59 * are in a linked list starting with unp_refs, linked through
60 * unp_nextref and null-terminated. Note that a socket may be referenced
61 * by a number of other sockets and may also reference a socket (not
62 * necessarily one which is referencing it). This generates
63 * the need for unp_refs and unp_nextref to be separate fields.
64 *
65 * Stream sockets keep copies of receive sockbuf sb_cc and sb_mbcnt
66 * so that changes in the sockbuf may be computed to modify
67 * back pressure on the sender accordingly.
68 */
69typedef u_quad_t unp_gen_t;
70LIST_HEAD(unp_head, unpcb);
71
72struct unpcb {
73 LIST_ENTRY(unpcb) unp_link; /* glue on list of all PCBs */
74 struct socket *unp_socket; /* pointer back to socket */
75 struct vnode *unp_vnode; /* if associated with file */
76 struct vnode *unp_rvnode; /* root vp for creating process */
77 ino_t unp_ino; /* fake inode number */
78 struct unpcb *unp_conn; /* control block of connected socket */
79 struct unp_head unp_refs; /* referencing socket linked list */
80 LIST_ENTRY(unpcb) unp_reflink; /* link in unp_refs list */
81 struct sockaddr_un *unp_addr; /* bound address of socket */
76d4bfa3 82 int unp_refcnt; /* referece count */
3a6117bb 83 int unused02;
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84 unp_gen_t unp_gencnt; /* generation count of this instance */
85 int unp_flags; /* flags */
86 struct xucred unp_peercred; /* peer credentials, if applicable */
87};
88
89/*
90 * Flags in unp_flags.
91 *
92 * UNP_HAVEPC - indicates that the unp_peercred member is filled in
93 * and is really the credentials of the connected peer. This is used
94 * to determine whether the contents should be sent to the user or
95 * not.
96 *
97 * UNP_HAVEPCCACHED - indicates that the unp_peercred member is filled
98 * in, but does *not* contain the credentials of the connected peer
99 * (there may not even be a peer). This is set in unp_listen() when
100 * it fills in unp_peercred for later consumption by unp_connect().
5df2d9a0 101 *
16e0b14d 102 * UNP_PRIVATE1, UNP_PRIVATE2, UNP_PRIVATE3 - Implementation private.
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103 */
104#define UNP_HAVEPC 0x001
105#define UNP_HAVEPCCACHED 0x002
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106#define UNP_PRIVATE1 0x004
107#define UNP_PRIVATE2 0x008
16e0b14d 108#define UNP_PRIVATE3 0x010
984263bc 109
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110/* Hack alert -- this structure depends on <sys/socketvar.h>. */
111#ifdef _SYS_SOCKETVAR_H_
112struct xunpcb {
113 size_t xu_len; /* length of this structure */
114 struct unpcb *xu_unpp; /* to help netstat, fstat */
115 struct unpcb xu_unp; /* our information */
116 union {
117 struct sockaddr_un xuu_addr; /* our bound address */
118 char xu_dummy1[256];
119 } xu_au;
120#define xu_addr xu_au.xuu_addr
121 union {
122 struct sockaddr_un xuu_caddr; /* their bound address */
123 char xu_dummy2[256];
124 } xu_cau;
125#define xu_caddr xu_cau.xuu_caddr
126 struct xsocket xu_socket;
127 u_quad_t xu_alignment_hack;
128};
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129#endif /* _SYS_SOCKETVAR_H_ */
130
131#endif /* _SYS_UNPCB_H_ */