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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * SUCS NET3:
3 *
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.
9 *
10 * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
11 * (from old tcp.c code)
Alan Cox113aa832008-10-13 19:01:08 -070012 * Alan Cox <alan@lxorguk.ukuu.org.uk> (Borrowed comments 8-))
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 */
14
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>
20#include <net/sock.h>
21
22/**
23 * sk_stream_write_space - stream socket write_space callback.
Pavel Pisa4dc3b162005-05-01 08:59:25 -070024 * @sk: socket
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 *
26 * FIXME: write proper description
27 */
28void sk_stream_write_space(struct sock *sk)
29{
30 struct socket *sock = sk->sk_socket;
Eric Dumazet43815482010-04-29 11:01:49 +000031 struct socket_wq *wq;
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Eric Dumazet64dc6132013-07-22 20:26:31 -070033 if (sk_stream_is_writeable(sk) && sock) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 clear_bit(SOCK_NOSPACE, &sock->flags);
35
Eric Dumazet43815482010-04-29 11:01:49 +000036 rcu_read_lock();
37 wq = rcu_dereference(sk->sk_wq);
38 if (wq_has_sleeper(wq))
39 wake_up_interruptible_poll(&wq->wait, POLLOUT |
John Dykstra9dc20c52009-05-12 15:34:50 +000040 POLLWRNORM | POLLWRBAND);
Eric Dumazet43815482010-04-29 11:01:49 +000041 if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
Pavel Emelyanov8d8ad9d2007-11-26 20:10:50 +080042 sock_wake_async(sock, SOCK_WAKE_SPACE, POLL_OUT);
Eric Dumazet43815482010-04-29 11:01:49 +000043 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 }
45}
Linus Torvalds1da177e2005-04-16 15:20:36 -070046EXPORT_SYMBOL(sk_stream_write_space);
47
48/**
49 * sk_stream_wait_connect - Wait for a socket to get into the connected state
Pavel Pisa4dc3b162005-05-01 08:59:25 -070050 * @sk: sock to wait on
51 * @timeo_p: for how long to wait
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 *
53 * Must be called with the socket locked.
54 */
55int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
56{
57 struct task_struct *tsk = current;
58 DEFINE_WAIT(wait);
Herbert Xu6151b312005-11-04 09:56:56 +110059 int done;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Herbert Xu6151b312005-11-04 09:56:56 +110061 do {
Benjamin LaHaisec1cbe4b2005-12-13 23:22:19 -080062 int err = sock_error(sk);
63 if (err)
64 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
66 return -EPIPE;
67 if (!*timeo_p)
68 return -EAGAIN;
69 if (signal_pending(tsk))
70 return sock_intr_errno(*timeo_p);
71
Eric Dumazetaa395142010-04-20 13:03:51 +000072 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 sk->sk_write_pending++;
Herbert Xu6151b312005-11-04 09:56:56 +110074 done = sk_wait_event(sk, timeo_p,
Benjamin LaHaisec1cbe4b2005-12-13 23:22:19 -080075 !sk->sk_err &&
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +090076 !((1 << sk->sk_state) &
Herbert Xu6151b312005-11-04 09:56:56 +110077 ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)));
Eric Dumazetaa395142010-04-20 13:03:51 +000078 finish_wait(sk_sleep(sk), &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 sk->sk_write_pending--;
Herbert Xu6151b312005-11-04 09:56:56 +110080 } while (!done);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 return 0;
82}
Linus Torvalds1da177e2005-04-16 15:20:36 -070083EXPORT_SYMBOL(sk_stream_wait_connect);
84
85/**
86 * sk_stream_closing - Return 1 if we still have things to send in our buffers.
Pavel Pisa4dc3b162005-05-01 08:59:25 -070087 * @sk: socket to verify
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 */
89static inline int sk_stream_closing(struct sock *sk)
90{
91 return (1 << sk->sk_state) &
92 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK);
93}
94
95void sk_stream_wait_close(struct sock *sk, long timeout)
96{
97 if (timeout) {
98 DEFINE_WAIT(wait);
99
100 do {
Eric Dumazetaa395142010-04-20 13:03:51 +0000101 prepare_to_wait(sk_sleep(sk), &wait,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 TASK_INTERRUPTIBLE);
103 if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk)))
104 break;
105 } while (!signal_pending(current) && timeout);
106
Eric Dumazetaa395142010-04-20 13:03:51 +0000107 finish_wait(sk_sleep(sk), &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 }
109}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110EXPORT_SYMBOL(sk_stream_wait_close);
111
112/**
113 * sk_stream_wait_memory - Wait for more memory for a socket
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700114 * @sk: socket to wait for memory
115 * @timeo_p: for how long
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 */
117int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
118{
119 int err = 0;
120 long vm_wait = 0;
121 long current_timeo = *timeo_p;
Jason Baron790ba452015-05-06 15:52:23 +0000122 bool noblock = (*timeo_p ? false : true);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 DEFINE_WAIT(wait);
124
125 if (sk_stream_memory_free(sk))
Aruna-Hewapathirane63862b52014-01-11 07:15:59 -0500126 current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
128 while (1) {
129 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
130
Eric Dumazetaa395142010-04-20 13:03:51 +0000131 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
133 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
134 goto do_error;
Jason Baron790ba452015-05-06 15:52:23 +0000135 if (!*timeo_p) {
136 if (noblock)
137 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 goto do_nonblock;
Jason Baron790ba452015-05-06 15:52:23 +0000139 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 if (signal_pending(current))
141 goto do_interrupted;
142 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
143 if (sk_stream_memory_free(sk) && !vm_wait)
144 break;
145
146 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
147 sk->sk_write_pending++;
Nagendra Tomar482964e2010-10-02 23:45:06 +0000148 sk_wait_event(sk, &current_timeo, sk->sk_err ||
149 (sk->sk_shutdown & SEND_SHUTDOWN) ||
150 (sk_stream_memory_free(sk) &&
151 !vm_wait));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 sk->sk_write_pending--;
153
154 if (vm_wait) {
155 vm_wait -= current_timeo;
156 current_timeo = *timeo_p;
157 if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
158 (current_timeo -= vm_wait) < 0)
159 current_timeo = 0;
160 vm_wait = 0;
161 }
162 *timeo_p = current_timeo;
163 }
164out:
Eric Dumazetaa395142010-04-20 13:03:51 +0000165 finish_wait(sk_sleep(sk), &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 return err;
167
168do_error:
169 err = -EPIPE;
170 goto out;
171do_nonblock:
172 err = -EAGAIN;
173 goto out;
174do_interrupted:
175 err = sock_intr_errno(*timeo_p);
176 goto out;
177}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178EXPORT_SYMBOL(sk_stream_wait_memory);
179
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180int sk_stream_error(struct sock *sk, int flags, int err)
181{
182 if (err == -EPIPE)
183 err = sock_error(sk) ? : -EPIPE;
184 if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
185 send_sig(SIGPIPE, current, 0);
186 return err;
187}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188EXPORT_SYMBOL(sk_stream_error);
189
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190void sk_stream_kill_queues(struct sock *sk)
191{
192 /* First the read buffer. */
193 __skb_queue_purge(&sk->sk_receive_queue);
194
195 /* Next, the error queue. */
196 __skb_queue_purge(&sk->sk_error_queue);
197
198 /* Next, the write queue. */
Ilpo Järvinen547b7922008-07-25 21:43:18 -0700199 WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
201 /* Account for returned memory. */
Hideo Aoki3ab224b2007-12-31 00:11:19 -0800202 sk_mem_reclaim(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
Ilpo Järvinen547b7922008-07-25 21:43:18 -0700204 WARN_ON(sk->sk_wmem_queued);
205 WARN_ON(sk->sk_forward_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
207 /* It is _impossible_ for the backlog to contain anything
208 * when we get here. All user references to this socket
209 * have gone away, only the net layer knows can touch it.
210 */
211}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212EXPORT_SYMBOL(sk_stream_kill_queues);