1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#ifndef _SYS_UNPCB_H_
33#define _SYS_UNPCB_H_
34
35typedef uint64_t unp_gen_t;
36
37#if defined(_KERNEL) || defined(_WANT_UNPCB)
38#include <sys/queue.h>
39#include <sys/ucred.h>
40
41/*
42 * Protocol control block for an active
43 * instance of a UNIX internal protocol.
44 *
45 * A socket may be associated with a vnode in the
46 * filesystem. If so, the unp_vnode pointer holds
47 * a reference count to this vnode, which should be irele'd
48 * when the socket goes away.
49 *
50 * A socket may be connected to another socket, in which
51 * case the control block of the socket to which it is connected
52 * is given by unp_conn.
53 *
54 * A socket may be referenced by a number of sockets (e.g. several
55 * sockets may be connected to a datagram socket.) These sockets
56 * are in a linked list starting with unp_refs, linked through
57 * unp_nextref and null-terminated. Note that a socket may be referenced
58 * by a number of other sockets and may also reference a socket (not
59 * necessarily one which is referencing it). This generates
60 * the need for unp_refs and unp_nextref to be separate fields.
61 *
62 * Stream sockets keep copies of receive sockbuf sb_cc and sb_mbcnt
63 * so that changes in the sockbuf may be computed to modify
64 * back pressure on the sender accordingly.
65 *
66 * Locking key:
67 * (a) Atomic
68 * (c) Constant
69 * (g) Locked using linkage lock
70 * (l) Locked using list lock
71 * (p) Locked using pcb lock
72 */
73LIST_HEAD(unp_head, unpcb);
74
75struct unpcb {
76 /* Cache line 1 */
77 struct mtx unp_mtx; /* PCB mutex */
78 struct unpcb *unp_conn; /* (p) connected socket */
79 volatile u_int unp_refcount; /* (a, p) atomic refcount */
80 short unp_flags; /* (p) PCB flags */
81 short unp_gcflag; /* (g) Garbage collector flags */
82 struct sockaddr_un *unp_addr; /* (p) bound address of socket */
83 struct socket *unp_socket; /* (c) pointer back to socket */
84 /* Cache line 2 */
85 u_int unp_pairbusy; /* (p) threads acquiring peer locks */
86 struct vnode *unp_vnode; /* (p) associated file if applicable */
87 struct xucred unp_peercred; /* (p) peer credentials if applicable */
88 LIST_ENTRY(unpcb) unp_reflink; /* (l) link in unp_refs list */
89 LIST_ENTRY(unpcb) unp_link; /* (g) glue on list of all PCBs */
90 struct unp_head unp_refs; /* (l) referencing socket linked list */
91 unp_gen_t unp_gencnt; /* (g) generation count of this item */
92 struct file *unp_file; /* (g) back-pointer to file for gc */
93 u_int unp_msgcount; /* (g) references from message queue */
94 u_int unp_gcrefs; /* (g) garbage collector refcount */
95 ino_t unp_ino; /* (g) fake inode number */
96 mode_t unp_mode; /* (g) initial pre-bind() mode */
97 LIST_ENTRY(unpcb) unp_dead; /* (g) link in dead list */
98} __aligned(CACHE_LINE_SIZE);
99
100/*
101 * Flags in unp_flags.
102 *
103 * UNP_HAVEPC - indicates that the unp_peercred member is filled in
104 * and is really the credentials of the connected peer. This is used
105 * to determine whether the contents should be sent to the user or
106 * not.
107 */
108#define UNP_HAVEPC 0x001
109#define UNP_WANTCRED_ALWAYS 0x002 /* credentials wanted always */
110#define UNP_WANTCRED_ONESHOT 0x004 /* credentials wanted once */
111#define UNP_WANTCRED_MASK (UNP_WANTCRED_ONESHOT | UNP_WANTCRED_ALWAYS)
112
113/*
114 * These flags are used to handle non-atomicity in connect() and bind()
115 * operations on a socket: in particular, to avoid races between multiple
116 * threads or processes operating simultaneously on the same socket.
117 */
118#define UNP_CONNECTING 0x010 /* Currently connecting. */
119#define UNP_BINDING 0x020 /* Currently binding. */
120#define UNP_WAITING 0x040 /* Peer state is changing. */
121
122/*
123 * Flags in unp_gcflag.
124 */
125#define UNPGC_DEAD 0x1 /* unpcb might be dead. */
126#define UNPGC_IGNORE_RIGHTS 0x2 /* Attached rights are freed */
127
128#define sotounpcb(so) ((struct unpcb *)((so)->so_pcb))
129
130#endif /* _KERNEL || _WANT_UNPCB */
131
132/*
133 * UNPCB structure exported to user-land via sysctl(3).
134 *
135 * Fields prefixed with "xu_" are unique to the export structure, and fields
136 * with "unp_" or other prefixes match corresponding fields of 'struct unpcb'.
137 *
138 * Legend:
139 * (s) - used by userland utilities in src
140 * (p) - used by utilities in ports
141 * (3) - is known to be used by third party software not in ports
142 * (n) - no known usage
143 *
144 * Evil hack: declare only if sys/socketvar.h have been included.
145 */
146#ifdef _SYS_SOCKETVAR_H_
147struct xunpcb {
148 ksize_t xu_len; /* length of this structure */
149 kvaddr_t xu_unpp; /* to help netstat, fstat */
150 kvaddr_t unp_vnode; /* (s) */
151 kvaddr_t unp_conn; /* (s) */
152 kvaddr_t xu_firstref; /* (s) */
153 kvaddr_t xu_nextref; /* (s) */
154 unp_gen_t unp_gencnt; /* (s) */
155 int64_t xu_spare64[8];
156 int32_t xu_spare32[8];
157 union {
158 struct sockaddr_un xu_addr; /* our bound address */
159 char xu_dummy1[256];
160 };
161 union {
162 struct sockaddr_un xu_caddr; /* their bound address */
163 char xu_dummy2[256];
164 };
165 struct xsocket xu_socket;
166} __aligned(MAX(8, sizeof(void *)));
167
168struct xunpgen {
169 ksize_t xug_len;
170 u_int xug_count;
171 unp_gen_t xug_gen;
172 so_gen_t xug_sogen;
173} __aligned(8);
174#endif /* _SYS_SOCKETVAR_H_ */
175
176#if defined(_KERNEL)
177struct thread;
178
179/* In uipc_userreq.c */
180void
181unp_copy_peercred(struct thread *td, struct unpcb *client_unp,
182 struct unpcb *server_unp, struct unpcb *listen_unp);
183#endif
184
185#endif /* _SYS_UNPCB_H_ */