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	LIST_ENTRY(unpcb) unp_dead;	/* (g) link in dead list */
97} __aligned(CACHE_LINE_SIZE);
98
99/*
100 * Flags in unp_flags.
101 *
102 * UNP_HAVEPC - indicates that the unp_peercred member is filled in
103 * and is really the credentials of the connected peer.  This is used
104 * to determine whether the contents should be sent to the user or
105 * not.
106 */
107#define	UNP_HAVEPC			0x001
108#define	UNP_WANTCRED_ALWAYS		0x002	/* credentials wanted always */
109#define	UNP_WANTCRED_ONESHOT		0x004	/* credentials wanted once */
110#define	UNP_WANTCRED_MASK	(UNP_WANTCRED_ONESHOT | UNP_WANTCRED_ALWAYS)
111
112/*
113 * These flags are used to handle non-atomicity in connect() and bind()
114 * operations on a socket: in particular, to avoid races between multiple
115 * threads or processes operating simultaneously on the same socket.
116 */
117#define	UNP_CONNECTING			0x010	/* Currently connecting. */
118#define	UNP_BINDING			0x020	/* Currently binding. */
119#define	UNP_WAITING			0x040	/* Peer state is changing. */
120
121/*
122 * Flags in unp_gcflag.
123 */
124#define	UNPGC_DEAD			0x1	/* unpcb might be dead. */
125#define	UNPGC_IGNORE_RIGHTS		0x2	/* Attached rights are freed */
126
127#define	sotounpcb(so)	((struct unpcb *)((so)->so_pcb))
128
129#endif	/* _KERNEL || _WANT_UNPCB */
130
131/*
132 * UNPCB structure exported to user-land via sysctl(3).
133 *
134 * Fields prefixed with "xu_" are unique to the export structure, and fields
135 * with "unp_" or other prefixes match corresponding fields of 'struct unpcb'.
136 *
137 * Legend:
138 * (s) - used by userland utilities in src
139 * (p) - used by utilities in ports
140 * (3) - is known to be used by third party software not in ports
141 * (n) - no known usage
142 *
143 * Evil hack: declare only if sys/socketvar.h have been included.
144 */
145#ifdef	_SYS_SOCKETVAR_H_
146struct xunpcb {
147	ksize_t		xu_len;			/* length of this structure */
148	kvaddr_t	xu_unpp;		/* to help netstat, fstat */
149	kvaddr_t	unp_vnode;		/* (s) */
150	kvaddr_t	unp_conn;		/* (s) */
151	kvaddr_t	xu_firstref;		/* (s) */
152	kvaddr_t	xu_nextref;		/* (s) */
153	unp_gen_t	unp_gencnt;		/* (s) */
154	int64_t		xu_spare64[8];
155	int32_t		xu_spare32[8];
156	union {
157		struct	sockaddr_un xu_addr;	/* our bound address */
158		char	xu_dummy1[256];
159	};
160	union {
161		struct	sockaddr_un xu_caddr;	/* their bound address */
162		char	xu_dummy2[256];
163	};
164	struct xsocket	xu_socket;
165} __aligned(MAX(8, sizeof(void *)));
166
167struct xunpgen {
168	ksize_t	xug_len;
169	u_int	xug_count;
170	unp_gen_t xug_gen;
171	so_gen_t xug_sogen;
172} __aligned(8);
173#endif /* _SYS_SOCKETVAR_H_ */
174
175#if defined(_KERNEL)
176struct thread;
177
178/* In uipc_userreq.c */
179void
180unp_copy_peercred(struct thread *td, struct unpcb *client_unp,
181    struct unpcb *server_unp, struct unpcb *listen_unp);
182#endif
183
184#endif /* _SYS_UNPCB_H_ */
185