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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_wspace(sk) >= sk_stream_min_wspace(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 | } |
46 | EXPORT_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 | */ |
55 | int 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 | } |
83 | EXPORT_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 | */ |
89 | static 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 | |
95 | void 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 | } |
110 | EXPORT_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 | */ |
117 | int 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 = (net_random() % (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, ¤t_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 | } |
160 | out: |
161 | finish_wait(sk_sleep(sk), &wait); |
162 | return err; |
163 | |
164 | do_error: |
165 | err = -EPIPE; |
166 | goto out; |
167 | do_nonblock: |
168 | err = -EAGAIN; |
169 | goto out; |
170 | do_interrupted: |
171 | err = sock_intr_errno(*timeo_p); |
172 | goto out; |
173 | } |
174 | EXPORT_SYMBOL(sk_stream_wait_memory); |
175 | |
176 | int 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 | } |
184 | EXPORT_SYMBOL(sk_stream_error); |
185 | |
186 | void 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 | } |
208 | EXPORT_SYMBOL(sk_stream_kill_queues); |
209 |
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