4 * Generic stream handling routines. These are generic for most
5 * protocols. Even IP. Tonight 8-).
6 * This is used because TCP, LLC (others too) layer all have mostly
7 * identical sendmsg() and recvmsg() code.
8 * So we (will) share it here.
10 * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
11 * (from old tcp.c code)
12 * Alan Cox <alan@lxorguk.ukuu.org.uk> (Borrowed comments 8-))
15 #include <linux/module.h>
16 #include <linux/net.h>
17 #include <linux/signal.h>
18 #include <linux/tcp.h>
19 #include <linux/wait.h>
23 * sk_stream_write_space - stream socket write_space callback.
26 * FIXME: write proper description
28 void sk_stream_write_space(struct sock *sk)
30 struct socket *sock = sk->sk_socket;
33 if (sk_stream_is_writeable(sk) && sock) {
34 clear_bit(SOCK_NOSPACE, &sock->flags);
37 wq = rcu_dereference(sk->sk_wq);
38 if (skwq_has_sleeper(wq))
39 wake_up_interruptible_poll(&wq->wait, POLLOUT |
40 POLLWRNORM | POLLWRBAND);
41 if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
42 sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
48 * sk_stream_wait_connect - Wait for a socket to get into the connected state
49 * @sk: sock to wait on
50 * @timeo_p: for how long to wait
52 * Must be called with the socket locked.
54 int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
56 struct task_struct *tsk = current;
61 int err = sock_error(sk);
64 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
68 if (signal_pending(tsk))
69 return sock_intr_errno(*timeo_p);
71 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
72 sk->sk_write_pending++;
73 done = sk_wait_event(sk, timeo_p,
75 !((1 << sk->sk_state) &
76 ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)));
77 finish_wait(sk_sleep(sk), &wait);
78 sk->sk_write_pending--;
82 EXPORT_SYMBOL(sk_stream_wait_connect);
85 * sk_stream_closing - Return 1 if we still have things to send in our buffers.
86 * @sk: socket to verify
88 static inline int sk_stream_closing(struct sock *sk)
90 return (1 << sk->sk_state) &
91 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK);
94 void sk_stream_wait_close(struct sock *sk, long timeout)
100 prepare_to_wait(sk_sleep(sk), &wait,
102 if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk)))
104 } while (!signal_pending(current) && timeout);
106 finish_wait(sk_sleep(sk), &wait);
109 EXPORT_SYMBOL(sk_stream_wait_close);
112 * sk_stream_wait_memory - Wait for more memory for a socket
113 * @sk: socket to wait for memory
114 * @timeo_p: for how long
116 int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
120 long current_timeo = *timeo_p;
123 if (sk_stream_memory_free(sk))
124 current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2;
127 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
129 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
131 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
135 if (signal_pending(current))
137 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
138 if (sk_stream_memory_free(sk) && !vm_wait)
141 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
142 sk->sk_write_pending++;
143 sk_wait_event(sk, ¤t_timeo, sk->sk_err ||
144 (sk->sk_shutdown & SEND_SHUTDOWN) ||
145 (sk_stream_memory_free(sk) &&
147 sk->sk_write_pending--;
150 vm_wait -= current_timeo;
151 current_timeo = *timeo_p;
152 if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
153 (current_timeo -= vm_wait) < 0)
157 *timeo_p = current_timeo;
160 finish_wait(sk_sleep(sk), &wait);
167 /* Make sure that whenever EAGAIN is returned, EPOLLOUT event can
168 * be generated later.
169 * When TCP receives ACK packets that make room, tcp_check_space()
170 * only calls tcp_new_space() if SOCK_NOSPACE is set.
172 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
176 err = sock_intr_errno(*timeo_p);
179 EXPORT_SYMBOL(sk_stream_wait_memory);
181 int sk_stream_error(struct sock *sk, int flags, int err)
184 err = sock_error(sk) ? : -EPIPE;
185 if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
186 send_sig(SIGPIPE, current, 0);
189 EXPORT_SYMBOL(sk_stream_error);
191 void sk_stream_kill_queues(struct sock *sk)
193 /* First the read buffer. */
194 __skb_queue_purge(&sk->sk_receive_queue);
196 /* Next, the write queue. */
197 WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
199 /* Account for returned memory. */
202 WARN_ON(sk->sk_wmem_queued);
203 WARN_ON(sk->sk_forward_alloc);
205 /* It is _impossible_ for the backlog to contain anything
206 * when we get here. All user references to this socket
207 * have gone away, only the net layer knows can touch it.
210 EXPORT_SYMBOL(sk_stream_kill_queues);