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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, 1) && 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 !READ_ONCE(sk->sk_err) &&
77 !((1 << READ_ONCE(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 done < 0 ? done : 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 int sk_stream_closing(const struct sock *sk)
91{
92 return (1 << READ_ONCE(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 ret, err = 0;
121 long vm_wait = 0;
122 long current_timeo = *timeo_p;
123 DEFINE_WAIT_FUNC(wait, woken_wake_function);
124
125 if (sk_stream_memory_free(sk))
126 current_timeo = vm_wait = get_random_u32_below(HZ / 5) + 2;
127
128 add_wait_queue(sk_sleep(sk), &wait);
129
130 while (1) {
131 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
132
133 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
134 goto do_error;
135 if (!*timeo_p)
136 goto do_eagain;
137 if (signal_pending(current))
138 goto do_interrupted;
139 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
140 if (sk_stream_memory_free(sk) && !vm_wait)
141 break;
142
143 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
144 sk->sk_write_pending++;
145 ret = sk_wait_event(sk, ¤t_timeo, READ_ONCE(sk->sk_err) ||
146 (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) ||
147 (sk_stream_memory_free(sk) && !vm_wait),
148 &wait);
149 sk->sk_write_pending--;
150 if (ret < 0)
151 goto do_error;
152
153 if (vm_wait) {
154 vm_wait -= current_timeo;
155 current_timeo = *timeo_p;
156 if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
157 (current_timeo -= vm_wait) < 0)
158 current_timeo = 0;
159 vm_wait = 0;
160 }
161 *timeo_p = current_timeo;
162 }
163out:
164 if (!sock_flag(sk, SOCK_DEAD))
165 remove_wait_queue(sk_sleep(sk), &wait);
166 return err;
167
168do_error:
169 err = -EPIPE;
170 goto out;
171do_eagain:
172 /* Make sure that whenever EAGAIN is returned, EPOLLOUT event can
173 * be generated later.
174 * When TCP receives ACK packets that make room, tcp_check_space()
175 * only calls tcp_new_space() if SOCK_NOSPACE is set.
176 */
177 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
178 err = -EAGAIN;
179 goto out;
180do_interrupted:
181 err = sock_intr_errno(*timeo_p);
182 goto out;
183}
184EXPORT_SYMBOL(sk_stream_wait_memory);
185
186int sk_stream_error(struct sock *sk, int flags, int err)
187{
188 if (err == -EPIPE)
189 err = sock_error(sk) ? : -EPIPE;
190 if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
191 send_sig(SIGPIPE, current, 0);
192 return err;
193}
194EXPORT_SYMBOL(sk_stream_error);
195
196void sk_stream_kill_queues(struct sock *sk)
197{
198 /* First the read buffer. */
199 __skb_queue_purge(&sk->sk_receive_queue);
200
201 /* Next, the error queue.
202 * We need to use queue lock, because other threads might
203 * add packets to the queue without socket lock being held.
204 */
205 skb_queue_purge(&sk->sk_error_queue);
206
207 /* Next, the write queue. */
208 WARN_ON_ONCE(!skb_queue_empty(&sk->sk_write_queue));
209
210 /* Account for returned memory. */
211 sk_mem_reclaim_final(sk);
212
213 WARN_ON_ONCE(sk->sk_wmem_queued);
214
215 /* It is _impossible_ for the backlog to contain anything
216 * when we get here. All user references to this socket
217 * have gone away, only the net layer knows can touch it.
218 */
219}
220EXPORT_SYMBOL(sk_stream_kill_queues);
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 (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);
43 rcu_read_unlock();
44 }
45}
46
47/**
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
51 *
52 * Must be called with the socket locked.
53 */
54int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
55{
56 DEFINE_WAIT_FUNC(wait, woken_wake_function);
57 struct task_struct *tsk = current;
58 int done;
59
60 do {
61 int err = sock_error(sk);
62 if (err)
63 return err;
64 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
65 return -EPIPE;
66 if (!*timeo_p)
67 return -EAGAIN;
68 if (signal_pending(tsk))
69 return sock_intr_errno(*timeo_p);
70
71 add_wait_queue(sk_sleep(sk), &wait);
72 sk->sk_write_pending++;
73 done = sk_wait_event(sk, timeo_p,
74 !sk->sk_err &&
75 !((1 << sk->sk_state) &
76 ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)), &wait);
77 remove_wait_queue(sk_sleep(sk), &wait);
78 sk->sk_write_pending--;
79 } while (!done);
80 return 0;
81}
82EXPORT_SYMBOL(sk_stream_wait_connect);
83
84/**
85 * sk_stream_closing - Return 1 if we still have things to send in our buffers.
86 * @sk: socket to verify
87 */
88static inline int sk_stream_closing(struct sock *sk)
89{
90 return (1 << sk->sk_state) &
91 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK);
92}
93
94void sk_stream_wait_close(struct sock *sk, long timeout)
95{
96 if (timeout) {
97 DEFINE_WAIT_FUNC(wait, woken_wake_function);
98
99 add_wait_queue(sk_sleep(sk), &wait);
100
101 do {
102 if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk), &wait))
103 break;
104 } while (!signal_pending(current) && timeout);
105
106 remove_wait_queue(sk_sleep(sk), &wait);
107 }
108}
109EXPORT_SYMBOL(sk_stream_wait_close);
110
111/**
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
115 */
116int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
117{
118 int err = 0;
119 long vm_wait = 0;
120 long current_timeo = *timeo_p;
121 bool noblock = (*timeo_p ? false : true);
122 DEFINE_WAIT_FUNC(wait, woken_wake_function);
123
124 if (sk_stream_memory_free(sk))
125 current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2;
126
127 add_wait_queue(sk_sleep(sk), &wait);
128
129 while (1) {
130 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
131
132 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
133 goto do_error;
134 if (!*timeo_p) {
135 if (noblock)
136 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
137 goto do_nonblock;
138 }
139 if (signal_pending(current))
140 goto do_interrupted;
141 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
142 if (sk_stream_memory_free(sk) && !vm_wait)
143 break;
144
145 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
146 sk->sk_write_pending++;
147 sk_wait_event(sk, ¤t_timeo, sk->sk_err ||
148 (sk->sk_shutdown & SEND_SHUTDOWN) ||
149 (sk_stream_memory_free(sk) &&
150 !vm_wait), &wait);
151 sk->sk_write_pending--;
152
153 if (vm_wait) {
154 vm_wait -= current_timeo;
155 current_timeo = *timeo_p;
156 if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
157 (current_timeo -= vm_wait) < 0)
158 current_timeo = 0;
159 vm_wait = 0;
160 }
161 *timeo_p = current_timeo;
162 }
163out:
164 remove_wait_queue(sk_sleep(sk), &wait);
165 return err;
166
167do_error:
168 err = -EPIPE;
169 goto out;
170do_nonblock:
171 err = -EAGAIN;
172 goto out;
173do_interrupted:
174 err = sock_intr_errno(*timeo_p);
175 goto out;
176}
177EXPORT_SYMBOL(sk_stream_wait_memory);
178
179int sk_stream_error(struct sock *sk, int flags, int err)
180{
181 if (err == -EPIPE)
182 err = sock_error(sk) ? : -EPIPE;
183 if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
184 send_sig(SIGPIPE, current, 0);
185 return err;
186}
187EXPORT_SYMBOL(sk_stream_error);
188
189void sk_stream_kill_queues(struct sock *sk)
190{
191 /* First the read buffer. */
192 __skb_queue_purge(&sk->sk_receive_queue);
193
194 /* Next, the error queue. */
195 __skb_queue_purge(&sk->sk_error_queue);
196
197 /* Next, the write queue. */
198 WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
199
200 /* Account for returned memory. */
201 sk_mem_reclaim(sk);
202
203 WARN_ON(sk->sk_wmem_queued);
204 WARN_ON(sk->sk_forward_alloc);
205
206 /* It is _impossible_ for the backlog to contain anything
207 * when we get here. All user references to this socket
208 * have gone away, only the net layer knows can touch it.
209 */
210}
211EXPORT_SYMBOL(sk_stream_kill_queues);