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 *	@(#)unpcb.h	8.1 (Berkeley) 6/2/93
 32 */
 33
 34#ifndef _SYS_UNPCB_H_
 35#define _SYS_UNPCB_H_
 36
 37typedef uint64_t unp_gen_t;
 38
 39#if defined(_KERNEL) || defined(_WANT_UNPCB)
 40#include <sys/queue.h>
 41#include <sys/ucred.h>
 42
 43/*
 44 * Protocol control block for an active
 45 * instance of a UNIX internal protocol.
 46 *
 47 * A socket may be associated with a vnode in the
 48 * filesystem.  If so, the unp_vnode pointer holds
 49 * a reference count to this vnode, which should be irele'd
 50 * when the socket goes away.
 51 *
 52 * A socket may be connected to another socket, in which
 53 * case the control block of the socket to which it is connected
 54 * is given by unp_conn.
 55 *
 56 * A socket may be referenced by a number of sockets (e.g. several
 57 * sockets may be connected to a datagram socket.)  These sockets
 58 * are in a linked list starting with unp_refs, linked through
 59 * unp_nextref and null-terminated.  Note that a socket may be referenced
 60 * by a number of other sockets and may also reference a socket (not
 61 * necessarily one which is referencing it).  This generates
 62 * the need for unp_refs and unp_nextref to be separate fields.
 63 *
 64 * Stream sockets keep copies of receive sockbuf sb_cc and sb_mbcnt
 65 * so that changes in the sockbuf may be computed to modify
 66 * back pressure on the sender accordingly.
 67 *
 68 * Locking key:
 69 * (a) Atomic
 70 * (c) Constant
 71 * (g) Locked using linkage lock
 72 * (l) Locked using list lock
 73 * (p) Locked using pcb lock
 74 */
 75LIST_HEAD(unp_head, unpcb);
 76
 77struct unpcb {
 78	/* Cache line 1 */
 79	struct	mtx unp_mtx;		/* PCB mutex */
 80	struct	unpcb *unp_conn;	/* (p) connected socket */
 81	volatile u_int unp_refcount;	/* (a, p) atomic refcount */
 82	short	unp_flags;		/* (p) PCB flags */
 83	short	unp_gcflag;		/* (g) Garbage collector flags */
 84	struct	sockaddr_un *unp_addr;	/* (p) bound address of socket */
 85	struct	socket *unp_socket;	/* (c) pointer back to socket */
 86	/* Cache line 2 */
 87	u_int	unp_pairbusy;		/* (p) threads acquiring peer locks */
 88	struct	vnode *unp_vnode;	/* (p) associated file if applicable */
 89	struct	xucred unp_peercred;	/* (p) peer credentials if applicable */
 90	LIST_ENTRY(unpcb) unp_reflink;	/* (l) link in unp_refs list */
 91	LIST_ENTRY(unpcb) unp_link; 	/* (g) glue on list of all PCBs */
 92	struct	unp_head unp_refs;	/* (l) referencing socket linked list */
 93	unp_gen_t unp_gencnt;		/* (g) generation count of this item */
 94	struct	file *unp_file;		/* (g) back-pointer to file for gc */
 95	u_int	unp_msgcount;		/* (g) references from message queue */
 96	u_int	unp_gcrefs;		/* (g) garbage collector refcount */
 97	ino_t	unp_ino;		/* (g) fake inode number */
 98	LIST_ENTRY(unpcb) unp_dead;	/* (g) link in dead list */
 99} __aligned(CACHE_LINE_SIZE);
100
101/*
102 * Flags in unp_flags.
103 *
104 * UNP_HAVEPC - indicates that the unp_peercred member is filled in
105 * and is really the credentials of the connected peer.  This is used
106 * to determine whether the contents should be sent to the user or
107 * not.
108 */
109#define	UNP_HAVEPC			0x001
110#define	UNP_WANTCRED_ALWAYS		0x002	/* credentials wanted always */
111#define	UNP_WANTCRED_ONESHOT		0x004	/* credentials wanted once */
112#define	UNP_CONNWAIT			0x008	/* connect blocks until accepted */
113
114#define	UNP_WANTCRED_MASK	(UNP_WANTCRED_ONESHOT | UNP_WANTCRED_ALWAYS)
115
116/*
117 * These flags are used to handle non-atomicity in connect() and bind()
118 * operations on a socket: in particular, to avoid races between multiple
119 * threads or processes operating simultaneously on the same socket.
120 */
121#define	UNP_CONNECTING			0x010	/* Currently connecting. */
122#define	UNP_BINDING			0x020	/* Currently binding. */
123#define	UNP_WAITING			0x040	/* Peer state is changing. */
124
125/*
126 * Flags in unp_gcflag.
127 */
128#define	UNPGC_DEAD			0x1	/* unpcb might be dead. */
129#define	UNPGC_IGNORE_RIGHTS		0x2	/* Attached rights are freed */
130
131#define	sotounpcb(so)	((struct unpcb *)((so)->so_pcb))
132
133#endif	/* _KERNEL || _WANT_UNPCB */
134
135/*
136 * UNPCB structure exported to user-land via sysctl(3).
137 *
138 * Fields prefixed with "xu_" are unique to the export structure, and fields
139 * with "unp_" or other prefixes match corresponding fields of 'struct unpcb'.
140 *
141 * Legend:
142 * (s) - used by userland utilities in src
143 * (p) - used by utilities in ports
144 * (3) - is known to be used by third party software not in ports
145 * (n) - no known usage
146 *
147 * Evil hack: declare only if sys/socketvar.h have been included.
148 */
149#ifdef	_SYS_SOCKETVAR_H_
150struct xunpcb {
151	ksize_t		xu_len;			/* length of this structure */
152	kvaddr_t	xu_unpp;		/* to help netstat, fstat */
153	kvaddr_t	unp_vnode;		/* (s) */
154	kvaddr_t	unp_conn;		/* (s) */
155	kvaddr_t	xu_firstref;		/* (s) */
156	kvaddr_t	xu_nextref;		/* (s) */
157	unp_gen_t	unp_gencnt;		/* (s) */
158	int64_t		xu_spare64[8];
159	int32_t		xu_spare32[8];
160	union {
161		struct	sockaddr_un xu_addr;	/* our bound address */
162		char	xu_dummy1[256];
163	};
164	union {
165		struct	sockaddr_un xu_caddr;	/* their bound address */
166		char	xu_dummy2[256];
167	};
168	struct xsocket	xu_socket;
169} __aligned(MAX(8, sizeof(void *)));
170
171struct xunpgen {
172	ksize_t	xug_len;
173	u_int	xug_count;
174	unp_gen_t xug_gen;
175	so_gen_t xug_sogen;
176} __aligned(8);
177#endif /* _SYS_SOCKETVAR_H_ */
178
179#if defined(_KERNEL)
180struct thread;
181
182/* In uipc_userreq.c */
183void
184unp_copy_peercred(struct thread *td, struct unpcb *client_unp,
185    struct unpcb *server_unp, struct unpcb *listen_unp);
186#endif
187
188#endif /* _SYS_UNPCB_H_ */