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v3.15
 
  1/*
  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)
 12 *                     Alan Cox <alan@lxorguk.ukuu.org.uk> (Borrowed comments 8-))
 13 */
 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.
 24 * @sk: socket
 25 *
 26 * FIXME: write proper description
 27 */
 28void sk_stream_write_space(struct sock *sk)
 29{
 30	struct socket *sock = sk->sk_socket;
 31	struct socket_wq *wq;
 32
 33	if (sk_stream_is_writeable(sk) && sock) {
 34		clear_bit(SOCK_NOSPACE, &sock->flags);
 35
 36		rcu_read_lock();
 37		wq = rcu_dereference(sk->sk_wq);
 38		if (wq_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(sock, SOCK_WAKE_SPACE, POLL_OUT);
 43		rcu_read_unlock();
 44	}
 45}
 46EXPORT_SYMBOL(sk_stream_write_space);
 47
 48/**
 49 * sk_stream_wait_connect - Wait for a socket to get into the connected state
 50 * @sk: sock to wait on
 51 * @timeo_p: for how long to wait
 52 *
 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);
 59	int done;
 60
 61	do {
 62		int err = sock_error(sk);
 63		if (err)
 64			return err;
 65		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
 72		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 73		sk->sk_write_pending++;
 74		done = sk_wait_event(sk, timeo_p,
 75				     !sk->sk_err &&
 76				     !((1 << sk->sk_state) &
 77				       ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)));
 78		finish_wait(sk_sleep(sk), &wait);
 79		sk->sk_write_pending--;
 80	} while (!done);
 81	return 0;
 82}
 83EXPORT_SYMBOL(sk_stream_wait_connect);
 84
 85/**
 86 * sk_stream_closing - Return 1 if we still have things to send in our buffers.
 87 * @sk: socket to verify
 88 */
 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 {
101			prepare_to_wait(sk_sleep(sk), &wait,
102					TASK_INTERRUPTIBLE);
103			if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk)))
104				break;
105		} while (!signal_pending(current) && timeout);
106
107		finish_wait(sk_sleep(sk), &wait);
108	}
109}
110EXPORT_SYMBOL(sk_stream_wait_close);
111
112/**
113 * sk_stream_wait_memory - Wait for more memory for a socket
114 * @sk: socket to wait for memory
115 * @timeo_p: for how long
116 */
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;
122	DEFINE_WAIT(wait);
 
123
124	if (sk_stream_memory_free(sk))
125		current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2;
126
127	while (1) {
128		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
129
130		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 
131
132		if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
133			goto do_error;
134		if (!*timeo_p)
 
 
135			goto do_nonblock;
 
136		if (signal_pending(current))
137			goto do_interrupted;
138		clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
139		if (sk_stream_memory_free(sk) && !vm_wait)
140			break;
141
142		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
143		sk->sk_write_pending++;
144		sk_wait_event(sk, &current_timeo, sk->sk_err ||
145						  (sk->sk_shutdown & SEND_SHUTDOWN) ||
146						  (sk_stream_memory_free(sk) &&
147						  !vm_wait));
148		sk->sk_write_pending--;
149
150		if (vm_wait) {
151			vm_wait -= current_timeo;
152			current_timeo = *timeo_p;
153			if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
154			    (current_timeo -= vm_wait) < 0)
155				current_timeo = 0;
156			vm_wait = 0;
157		}
158		*timeo_p = current_timeo;
159	}
160out:
161	finish_wait(sk_sleep(sk), &wait);
162	return err;
163
164do_error:
165	err = -EPIPE;
166	goto out;
167do_nonblock:
168	err = -EAGAIN;
169	goto out;
170do_interrupted:
171	err = sock_intr_errno(*timeo_p);
172	goto out;
173}
174EXPORT_SYMBOL(sk_stream_wait_memory);
175
176int sk_stream_error(struct sock *sk, int flags, int err)
177{
178	if (err == -EPIPE)
179		err = sock_error(sk) ? : -EPIPE;
180	if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
181		send_sig(SIGPIPE, current, 0);
182	return err;
183}
184EXPORT_SYMBOL(sk_stream_error);
185
186void sk_stream_kill_queues(struct sock *sk)
187{
188	/* First the read buffer. */
189	__skb_queue_purge(&sk->sk_receive_queue);
190
191	/* Next, the error queue. */
192	__skb_queue_purge(&sk->sk_error_queue);
193
194	/* Next, the write queue. */
195	WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
196
197	/* Account for returned memory. */
198	sk_mem_reclaim(sk);
199
200	WARN_ON(sk->sk_wmem_queued);
201	WARN_ON(sk->sk_forward_alloc);
202
203	/* It is _impossible_ for the backlog to contain anything
204	 * when we get here.  All user references to this socket
205	 * have gone away, only the net layer knows can touch it.
206	 */
207}
208EXPORT_SYMBOL(sk_stream_kill_queues);
v4.17
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *     SUCS NET3:
  4 *
  5 *     Generic stream handling routines. These are generic for most
  6 *     protocols. Even IP. Tonight 8-).
  7 *     This is used because TCP, LLC (others too) layer all have mostly
  8 *     identical sendmsg() and recvmsg() code.
  9 *     So we (will) share it here.
 10 *
 11 *     Authors:        Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 12 *                     (from old tcp.c code)
 13 *                     Alan Cox <alan@lxorguk.ukuu.org.uk> (Borrowed comments 8-))
 14 */
 15
 16#include <linux/module.h>
 17#include <linux/sched/signal.h>
 18#include <linux/net.h>
 19#include <linux/signal.h>
 20#include <linux/tcp.h>
 21#include <linux/wait.h>
 22#include <net/sock.h>
 23
 24/**
 25 * sk_stream_write_space - stream socket write_space callback.
 26 * @sk: socket
 27 *
 28 * FIXME: write proper description
 29 */
 30void sk_stream_write_space(struct sock *sk)
 31{
 32	struct socket *sock = sk->sk_socket;
 33	struct socket_wq *wq;
 34
 35	if (sk_stream_is_writeable(sk) && sock) {
 36		clear_bit(SOCK_NOSPACE, &sock->flags);
 37
 38		rcu_read_lock();
 39		wq = rcu_dereference(sk->sk_wq);
 40		if (skwq_has_sleeper(wq))
 41			wake_up_interruptible_poll(&wq->wait, EPOLLOUT |
 42						EPOLLWRNORM | EPOLLWRBAND);
 43		if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
 44			sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
 45		rcu_read_unlock();
 46	}
 47}
 
 48
 49/**
 50 * sk_stream_wait_connect - Wait for a socket to get into the connected state
 51 * @sk: sock to wait on
 52 * @timeo_p: for how long to wait
 53 *
 54 * Must be called with the socket locked.
 55 */
 56int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
 57{
 58	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 59	struct task_struct *tsk = current;
 
 60	int done;
 61
 62	do {
 63		int err = sock_error(sk);
 64		if (err)
 65			return err;
 66		if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
 67			return -EPIPE;
 68		if (!*timeo_p)
 69			return -EAGAIN;
 70		if (signal_pending(tsk))
 71			return sock_intr_errno(*timeo_p);
 72
 73		add_wait_queue(sk_sleep(sk), &wait);
 74		sk->sk_write_pending++;
 75		done = sk_wait_event(sk, timeo_p,
 76				     !sk->sk_err &&
 77				     !((1 << sk->sk_state) &
 78				       ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)), &wait);
 79		remove_wait_queue(sk_sleep(sk), &wait);
 80		sk->sk_write_pending--;
 81	} while (!done);
 82	return 0;
 83}
 84EXPORT_SYMBOL(sk_stream_wait_connect);
 85
 86/**
 87 * sk_stream_closing - Return 1 if we still have things to send in our buffers.
 88 * @sk: socket to verify
 89 */
 90static inline int sk_stream_closing(struct sock *sk)
 91{
 92	return (1 << sk->sk_state) &
 93	       (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK);
 94}
 95
 96void sk_stream_wait_close(struct sock *sk, long timeout)
 97{
 98	if (timeout) {
 99		DEFINE_WAIT_FUNC(wait, woken_wake_function);
100
101		add_wait_queue(sk_sleep(sk), &wait);
102
103		do {
104			if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk), &wait))
 
 
105				break;
106		} while (!signal_pending(current) && timeout);
107
108		remove_wait_queue(sk_sleep(sk), &wait);
109	}
110}
111EXPORT_SYMBOL(sk_stream_wait_close);
112
113/**
114 * sk_stream_wait_memory - Wait for more memory for a socket
115 * @sk: socket to wait for memory
116 * @timeo_p: for how long
117 */
118int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
119{
120	int err = 0;
121	long vm_wait = 0;
122	long current_timeo = *timeo_p;
123	bool noblock = (*timeo_p ? false : true);
124	DEFINE_WAIT_FUNC(wait, woken_wake_function);
125
126	if (sk_stream_memory_free(sk))
127		current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2;
128
129	add_wait_queue(sk_sleep(sk), &wait);
 
130
131	while (1) {
132		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
133
134		if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
135			goto do_error;
136		if (!*timeo_p) {
137			if (noblock)
138				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
139			goto do_nonblock;
140		}
141		if (signal_pending(current))
142			goto do_interrupted;
143		sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
144		if (sk_stream_memory_free(sk) && !vm_wait)
145			break;
146
147		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
148		sk->sk_write_pending++;
149		sk_wait_event(sk, &current_timeo, sk->sk_err ||
150						  (sk->sk_shutdown & SEND_SHUTDOWN) ||
151						  (sk_stream_memory_free(sk) &&
152						  !vm_wait), &wait);
153		sk->sk_write_pending--;
154
155		if (vm_wait) {
156			vm_wait -= current_timeo;
157			current_timeo = *timeo_p;
158			if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
159			    (current_timeo -= vm_wait) < 0)
160				current_timeo = 0;
161			vm_wait = 0;
162		}
163		*timeo_p = current_timeo;
164	}
165out:
166	remove_wait_queue(sk_sleep(sk), &wait);
167	return err;
168
169do_error:
170	err = -EPIPE;
171	goto out;
172do_nonblock:
173	err = -EAGAIN;
174	goto out;
175do_interrupted:
176	err = sock_intr_errno(*timeo_p);
177	goto out;
178}
179EXPORT_SYMBOL(sk_stream_wait_memory);
180
181int sk_stream_error(struct sock *sk, int flags, int err)
182{
183	if (err == -EPIPE)
184		err = sock_error(sk) ? : -EPIPE;
185	if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
186		send_sig(SIGPIPE, current, 0);
187	return err;
188}
189EXPORT_SYMBOL(sk_stream_error);
190
191void sk_stream_kill_queues(struct sock *sk)
192{
193	/* First the read buffer. */
194	__skb_queue_purge(&sk->sk_receive_queue);
195
196	/* Next, the error queue. */
197	__skb_queue_purge(&sk->sk_error_queue);
198
199	/* Next, the write queue. */
200	WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
201
202	/* Account for returned memory. */
203	sk_mem_reclaim(sk);
204
205	WARN_ON(sk->sk_wmem_queued);
206	WARN_ON(sk->sk_forward_alloc);
207
208	/* It is _impossible_ for the backlog to contain anything
209	 * when we get here.  All user references to this socket
210	 * have gone away, only the net layer knows can touch it.
211	 */
212}
213EXPORT_SYMBOL(sk_stream_kill_queues);