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31 * @(#)unpcb.h 8.1 (Berkeley) 6/2/93
37 typedef uint64_t unp_gen_t;
39 #if defined(_KERNEL) || defined(_WANT_UNPCB)
40 #include <sys/queue.h>
41 #include <sys/ucred.h>
44 * Protocol control block for an active
45 * instance of a UNIX internal protocol.
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.
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.
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.
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.
71 * (g) Locked using linkage lock
72 * (l) Locked using list lock
73 * (p) Locked using pcb lock
75 LIST_HEAD(unp_head, unpcb);
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 */
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);
102 * Flags in unp_flags.
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
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 */
114 #define UNP_WANTCRED_MASK (UNP_WANTCRED_ONESHOT | UNP_WANTCRED_ALWAYS)
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.
121 #define UNP_CONNECTING 0x010 /* Currently connecting. */
122 #define UNP_BINDING 0x020 /* Currently binding. */
123 #define UNP_WAITING 0x040 /* Peer state is changing. */
126 * Flags in unp_gcflag.
128 #define UNPGC_DEAD 0x1 /* unpcb might be dead. */
129 #define UNPGC_IGNORE_RIGHTS 0x2 /* Attached rights are freed */
131 #define sotounpcb(so) ((struct unpcb *)((so)->so_pcb))
133 #endif /* _KERNEL || _WANT_UNPCB */
136 * UNPCB structure exported to user-land via sysctl(3).
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'.
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
147 * Evil hack: declare only if sys/socketvar.h have been included.
149 #ifdef _SYS_SOCKETVAR_H_
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];
161 struct sockaddr_un xu_addr; /* our bound address */
165 struct sockaddr_un xu_caddr; /* their bound address */
168 struct xsocket xu_socket;
169 } __aligned(MAX(8, sizeof(void *)));
177 #endif /* _SYS_SOCKETVAR_H_ */
182 /* In uipc_userreq.c */
184 unp_copy_peercred(struct thread *td, struct unpcb *client_unp,
185 struct unpcb *server_unp, struct unpcb *listen_unp);
188 #endif /* _SYS_UNPCB_H_ */