/* *     SUCS NET3: * *     Generic stream handling routines. These are generic for most *     protocols. Even IP. Tonight 8-). *     This is used because TCP, LLC (others too) layer all have mostly *     identical sendmsg() and recvmsg() code. *     So we (will) share it here. * *     Authors:        Arnaldo Carvalho de Melo <acme@conectiva.com.br> *                     (from old tcp.c code) *                     Alan Cox <alan@lxorguk.ukuu.org.uk> (Borrowed comments 8-)) */ #include <linux/module.h>#include <linux/net.h>#include <linux/signal.h>#include <linux/tcp.h>#include <linux/wait.h>#include <net/sock.h> /** * sk_stream_write_space - stream socket write_space callback. * @sk: socket * * FIXME: write proper description */void sk_stream_write_space(struct sock *sk){	struct socket *sock = sk->sk_socket;	struct socket_wq *wq; 	if (sk_stream_is_writeable(sk) && sock) {		clear_bit(SOCK_NOSPACE, &sock->flags); 		rcu_read_lock();		wq = rcu_dereference(sk->sk_wq);		if (wq_has_sleeper(wq))			wake_up_interruptible_poll(&wq->wait, POLLOUT |						POLLWRNORM | POLLWRBAND);		if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))			sock_wake_async(sock, SOCK_WAKE_SPACE, POLL_OUT);		rcu_read_unlock();	}}EXPORT_SYMBOL(sk_stream_write_space); /** * sk_stream_wait_connect - Wait for a socket to get into the connected state * @sk: sock to wait on * @timeo_p: for how long to wait * * Must be called with the socket locked. */int sk_stream_wait_connect(struct sock *sk, long *timeo_p){	struct task_struct *tsk = current;	DEFINE_WAIT(wait);	int done; 	do {		int err = sock_error(sk);		if (err)			return err;		if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))			return -EPIPE;		if (!*timeo_p)			return -EAGAIN;		if (signal_pending(tsk))			return sock_intr_errno(*timeo_p); 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);		sk->sk_write_pending++;		done = sk_wait_event(sk, timeo_p,				     !sk->sk_err &&				     !((1 << sk->sk_state) &				       ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)));		finish_wait(sk_sleep(sk), &wait);		sk->sk_write_pending--;	} while (!done);	return 0;}EXPORT_SYMBOL(sk_stream_wait_connect); /** * sk_stream_closing - Return 1 if we still have things to send in our buffers. * @sk: socket to verify */static inline int sk_stream_closing(struct sock *sk){	return (1 << sk->sk_state) &	       (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK);} void sk_stream_wait_close(struct sock *sk, long timeout){	if (timeout) {		DEFINE_WAIT(wait); 		do {			prepare_to_wait(sk_sleep(sk), &wait,					TASK_INTERRUPTIBLE);			if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk)))				break;		} while (!signal_pending(current) && timeout); 		finish_wait(sk_sleep(sk), &wait);	}}EXPORT_SYMBOL(sk_stream_wait_close); /** * sk_stream_wait_memory - Wait for more memory for a socket * @sk: socket to wait for memory * @timeo_p: for how long */int sk_stream_wait_memory(struct sock *sk, long *timeo_p){	int err = 0;	long vm_wait = 0;	long current_timeo = *timeo_p;	DEFINE_WAIT(wait); 	if (sk_stream_memory_free(sk))		current_timeo = vm_wait = (net_random() % (HZ / 5)) + 2; 	while (1) {		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 		if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))			goto do_error;		if (!*timeo_p)			goto do_nonblock;		if (signal_pending(current))			goto do_interrupted;		clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);		if (sk_stream_memory_free(sk) && !vm_wait)			break; 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);		sk->sk_write_pending++;		sk_wait_event(sk, &current_timeo, sk->sk_err ||						  (sk->sk_shutdown & SEND_SHUTDOWN) ||						  (sk_stream_memory_free(sk) &&						  !vm_wait));		sk->sk_write_pending--; 		if (vm_wait) {			vm_wait -= current_timeo;			current_timeo = *timeo_p;			if (current_timeo != MAX_SCHEDULE_TIMEOUT &&			    (current_timeo -= vm_wait) < 0)				current_timeo = 0;			vm_wait = 0;		}		*timeo_p = current_timeo;	}out:	finish_wait(sk_sleep(sk), &wait);	return err; do_error:	err = -EPIPE;	goto out;do_nonblock:	err = -EAGAIN;	goto out;do_interrupted:	err = sock_intr_errno(*timeo_p);	goto out;}EXPORT_SYMBOL(sk_stream_wait_memory); int sk_stream_error(struct sock *sk, int flags, int err){	if (err == -EPIPE)		err = sock_error(sk) ? : -EPIPE;	if (err == -EPIPE && !(flags & MSG_NOSIGNAL))		send_sig(SIGPIPE, current, 0);	return err;}EXPORT_SYMBOL(sk_stream_error); void sk_stream_kill_queues(struct sock *sk){	/* First the read buffer. */	__skb_queue_purge(&sk->sk_receive_queue); 	/* Next, the error queue. */	__skb_queue_purge(&sk->sk_error_queue); 	/* Next, the write queue. */	WARN_ON(!skb_queue_empty(&sk->sk_write_queue)); 	/* Account for returned memory. */	sk_mem_reclaim(sk); 	WARN_ON(sk->sk_wmem_queued);	WARN_ON(sk->sk_forward_alloc); 	/* It is _impossible_ for the backlog to contain anything	 * when we get here.  All user references to this socket	 * have gone away, only the net layer knows can touch it.	 */}EXPORT_SYMBOL(sk_stream_kill_queues);