2  * net/tipc/socket.c: TIPC socket API
43 #define SS_LISTENING	-1	/* socket is listening */
44 #define SS_READY	-2	/* socket is connectionless */
77  * Revised TIPC socket locking policy:
79  * Most socket operations take the standard socket lock when they start
81  * this lock grants the owner exclusive access to the fields of the socket
82  * data structures, with the exception of the backlog queue.  A few socket
83  * operations can be done without taking the socket lock because they only
84  * read socket information that never changes during the life of the socket.
86  * Socket operations may acquire the lock for the associated TIPC port if they
88  * both the socket lock and the port lock it must take the socket lock first
91  * The dispatcher handling incoming messages cannot grab the socket lock in
93  * Instead, it checks to see if the socket lock is currently owned by someone,
94  * and either handles the message itself or adds it to the socket's backlog
96  * owning the socket lock releases it.
98  * NOTE: Releasing the socket lock while an operation is sleeping overcomes
99  * the problem of a blocked socket operation preventing any other operations
101  * multiple threads trying to send (or receive) on the same socket, as these
107  * NOTE: Releasing the socket lock while an operation is sleeping also ensures
111  * NOTE: This code assumes that certain fields of a port/socket pair are
113  * the socket lock and/or port lock, and do not need to be re-read even
115  *   - socket type
116  *   - pointer to socket sk structure (aka tipc_sock structure)
122  * advance_rx_queue - discard first buffer in socket receive queue
124  * Caller must hold socket lock
134  * discard_rx_queue - discard all buffers in socket receive queue
136  * Caller must hold socket lock
150  * reject_rx_queue - reject all buffers in socket receive queue
152  * Caller must hold socket lock
166  * tipc_create - create a TIPC socket
168  * @sock: pre-allocated socket structure
172  * This routine creates additional data structures used by the TIPC socket,
178 static int tipc_create(struct net *net, struct socket *sock, int protocol,  in tipc_create()
209 	/* Allocate socket's protocol area */  in tipc_create()
215 	/* Allocate TIPC port for socket to use */  in tipc_create()
224 	/* Finish initializing socket data structures */  in tipc_create()
246  * release - destroy a TIPC socket
247  * @sock: socket to destroy
249  * This routine cleans up any messages that are still queued on the socket.
250  * For DGRAM and RDM socket types, all queued messages are rejected.
251  * For SEQPACKET and STREAM socket types, the first message is rejected
252  * and any others are discarded.  (If the first message on a STREAM socket
262 static int release(struct socket *sock)  in release()
270 	 * Exit if socket isn't fully initialized (occurs when a failed accept()  in release()
271 	 * releases a pre-allocated child socket that was never used)  in release()
325  * bind - associate or disassocate TIPC name(s) with a socket
326  * @sock: socket structure
327  * @uaddr: socket address describing name(s) and desired operation
328  * @uaddr_len: size of socket address data structure
332  * (i.e. a socket address length of 0) unbinds all names from the socket.
336  * NOTE: This routine doesn't need to take the socket lock since it doesn't
337  *       access any non-constant socket information.
340 static int bind(struct socket *sock, struct sockaddr *uaddr, int uaddr_len)  in bind()
364  * get_name - get port ID of socket or peer socket
365  * @sock: socket structure
366  * @uaddr: area for returned socket address
367  * @uaddr_len: area for returned length of socket address
372  * NOTE: This routine doesn't need to take the socket lock since it only
373  *       accesses socket information that is unchanging (or which changes in
377 static int get_name(struct socket *sock, struct sockaddr *uaddr,  in get_name()
406  * @file: file structure associated with the socket
407  * @sock: socket for which to calculate the poll bits
413  * It appears that the usual socket locking mechanisms are not useful here
420  * socket state		flags set
445 static unsigned int poll(struct file *file, struct socket *sock,  in poll()
506  * @iocb: if NULL, indicates that socket lock is already held
507  * @sock: socket structure
519 static int send_msg(struct kiocb *iocb, struct socket *sock,  in send_msg()
622  * @iocb: if NULL, indicates that socket lock is already held
623  * @sock: socket structure
632 static int send_packet(struct kiocb *iocb, struct socket *sock,  in send_packet()
686  * @sock: socket structure
696 static int send_stream(struct kiocb *iocb, struct socket *sock,  in send_stream()
791  * @sock: socket structure
797 static int auto_connect(struct socket *sock, struct tipc_msg *msg)  in auto_connect()
924 static int recv_msg(struct kiocb *iocb, struct socket *sock,  in recv_msg()
1047 static int recv_stream(struct kiocb *iocb, struct socket *sock,  in recv_stream()
1204  * @sk: socket
1208  * disconnect indication for a connected socket.
1210  * Called with socket lock already taken; port lock may also be taken.
1217 	struct socket *sock = sk->sk_socket;  in filter_rcv()
1221 	/* Reject message if it is wrong sort of message for socket */  in filter_rcv()
1285  * @sk: socket
1288  * Caller must hold socket lock, but not port lock.
1319 	 * Process message if socket is unlocked; otherwise add to backlog queue  in dispatch()
1356  * @sock: socket structure
1357  * @dest: socket address for destination port
1358  * @destlen: size of socket address data structure
1359  * @flags: file-related flags associated with socket
1364 static int connect(struct socket *sock, struct sockaddr *dest, int destlen,  in connect()
1391 	/* Issue Posix-compliant error code if socket is in the wrong state */  in connect()
1470  * listen - allow socket to listen for incoming connections
1471  * @sock: socket structure
1477 static int listen(struct socket *sock, int len)  in listen()
1497  * @sock: listening socket
1498  * @newsock: new socket that is to be connected
1499  * @flags: file-related flags associated with socket
1504 static int accept(struct socket *sock, struct socket *new_sock, int flags)  in accept()
1543 		 * Reject any stray messages received by new socket  in accept()
1544 		 * before the socket lock was taken (very, very unlikely)  in accept()
1549 		/* Connect new socket to it's peer */  in accept()
1564 		 * Respond to 'SYN+' by queuing it on new socket.  in accept()
1584  * shutdown - shutdown socket connection
1585  * @sock: socket structure
1588  * Terminates connection (if necessary), then purges socket's receive queue.
1593 static int shutdown(struct socket *sock, int how)  in shutdown()
1647  * setsockopt - set socket option
1648  * @sock: socket structure
1660 static int setsockopt(struct socket *sock,  in setsockopt()
1707  * getsockopt - get socket option
1708  * @sock: socket structure
1720 static int getsockopt(struct socket *sock,  in getsockopt()
1857  * tipc_socket_init - initialize TIPC socket interface
1873 		err("Failed to register TIPC socket type\n");  in tipc_socket_init()
1884  * tipc_socket_stop - stop TIPC socket interface