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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 | */ | |
28 | void 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 | */ | |
54 | int 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 | } | |
82 | EXPORT_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 | */ | |
88 | static 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 | ||
94 | void 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 | } | |
109 | EXPORT_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 | */ | |
116 | int 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 | } | |
163 | out: | |
164 | remove_wait_queue(sk_sleep(sk), &wait); | |
165 | return err; | |
166 | ||
167 | do_error: | |
168 | err = -EPIPE; | |
169 | goto out; | |
170 | do_nonblock: | |
171 | err = -EAGAIN; | |
172 | goto out; | |
173 | do_interrupted: | |
174 | err = sock_intr_errno(*timeo_p); | |
175 | goto out; | |
176 | } | |
177 | EXPORT_SYMBOL(sk_stream_wait_memory); | |
178 | ||
179 | int 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 | } | |
187 | EXPORT_SYMBOL(sk_stream_error); | |
188 | ||
189 | void 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 | } | |
211 | EXPORT_SYMBOL(sk_stream_kill_queues); |