Commit | Line | Data |
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1da177e4 LT |
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@redhat.com> (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. | |
4dc3b16b | 24 | * @sk: socket |
1da177e4 LT |
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 | ||
32 | if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) && sock) { | |
33 | clear_bit(SOCK_NOSPACE, &sock->flags); | |
34 | ||
35 | if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) | |
36 | wake_up_interruptible(sk->sk_sleep); | |
37 | if (sock->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN)) | |
38 | sock_wake_async(sock, 2, POLL_OUT); | |
39 | } | |
40 | } | |
41 | ||
42 | EXPORT_SYMBOL(sk_stream_write_space); | |
43 | ||
44 | /** | |
45 | * sk_stream_wait_connect - Wait for a socket to get into the connected state | |
4dc3b16b PP |
46 | * @sk: sock to wait on |
47 | * @timeo_p: for how long to wait | |
1da177e4 LT |
48 | * |
49 | * Must be called with the socket locked. | |
50 | */ | |
51 | int sk_stream_wait_connect(struct sock *sk, long *timeo_p) | |
52 | { | |
53 | struct task_struct *tsk = current; | |
54 | DEFINE_WAIT(wait); | |
6151b31c | 55 | int done; |
1da177e4 | 56 | |
6151b31c | 57 | do { |
c1cbe4b7 BL |
58 | int err = sock_error(sk); |
59 | if (err) | |
60 | return err; | |
1da177e4 LT |
61 | if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) |
62 | return -EPIPE; | |
63 | if (!*timeo_p) | |
64 | return -EAGAIN; | |
65 | if (signal_pending(tsk)) | |
66 | return sock_intr_errno(*timeo_p); | |
67 | ||
68 | prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); | |
69 | sk->sk_write_pending++; | |
6151b31c | 70 | done = sk_wait_event(sk, timeo_p, |
c1cbe4b7 | 71 | !sk->sk_err && |
4ec93edb | 72 | !((1 << sk->sk_state) & |
6151b31c | 73 | ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))); |
1da177e4 LT |
74 | finish_wait(sk->sk_sleep, &wait); |
75 | sk->sk_write_pending--; | |
6151b31c | 76 | } while (!done); |
1da177e4 LT |
77 | return 0; |
78 | } | |
79 | ||
80 | EXPORT_SYMBOL(sk_stream_wait_connect); | |
81 | ||
82 | /** | |
83 | * sk_stream_closing - Return 1 if we still have things to send in our buffers. | |
4dc3b16b | 84 | * @sk: socket to verify |
1da177e4 LT |
85 | */ |
86 | static inline int sk_stream_closing(struct sock *sk) | |
87 | { | |
88 | return (1 << sk->sk_state) & | |
89 | (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK); | |
90 | } | |
91 | ||
92 | void sk_stream_wait_close(struct sock *sk, long timeout) | |
93 | { | |
94 | if (timeout) { | |
95 | DEFINE_WAIT(wait); | |
96 | ||
97 | do { | |
98 | prepare_to_wait(sk->sk_sleep, &wait, | |
99 | TASK_INTERRUPTIBLE); | |
100 | if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk))) | |
101 | break; | |
102 | } while (!signal_pending(current) && timeout); | |
103 | ||
104 | finish_wait(sk->sk_sleep, &wait); | |
105 | } | |
106 | } | |
107 | ||
108 | EXPORT_SYMBOL(sk_stream_wait_close); | |
109 | ||
110 | /** | |
111 | * sk_stream_wait_memory - Wait for more memory for a socket | |
4dc3b16b PP |
112 | * @sk: socket to wait for memory |
113 | * @timeo_p: for how long | |
1da177e4 LT |
114 | */ |
115 | int sk_stream_wait_memory(struct sock *sk, long *timeo_p) | |
116 | { | |
117 | int err = 0; | |
118 | long vm_wait = 0; | |
119 | long current_timeo = *timeo_p; | |
120 | DEFINE_WAIT(wait); | |
121 | ||
122 | if (sk_stream_memory_free(sk)) | |
123 | current_timeo = vm_wait = (net_random() % (HZ / 5)) + 2; | |
124 | ||
125 | while (1) { | |
126 | set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); | |
127 | ||
128 | prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); | |
129 | ||
130 | if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) | |
131 | goto do_error; | |
132 | if (!*timeo_p) | |
133 | goto do_nonblock; | |
134 | if (signal_pending(current)) | |
135 | goto do_interrupted; | |
136 | clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); | |
137 | if (sk_stream_memory_free(sk) && !vm_wait) | |
138 | break; | |
139 | ||
140 | set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); | |
141 | sk->sk_write_pending++; | |
4ec93edb | 142 | sk_wait_event(sk, ¤t_timeo, !sk->sk_err && |
c1cbe4b7 BL |
143 | !(sk->sk_shutdown & SEND_SHUTDOWN) && |
144 | sk_stream_memory_free(sk) && | |
1da177e4 LT |
145 | vm_wait); |
146 | sk->sk_write_pending--; | |
147 | ||
148 | if (vm_wait) { | |
149 | vm_wait -= current_timeo; | |
150 | current_timeo = *timeo_p; | |
151 | if (current_timeo != MAX_SCHEDULE_TIMEOUT && | |
152 | (current_timeo -= vm_wait) < 0) | |
153 | current_timeo = 0; | |
154 | vm_wait = 0; | |
155 | } | |
156 | *timeo_p = current_timeo; | |
157 | } | |
158 | out: | |
159 | finish_wait(sk->sk_sleep, &wait); | |
160 | return err; | |
161 | ||
162 | do_error: | |
163 | err = -EPIPE; | |
164 | goto out; | |
165 | do_nonblock: | |
166 | err = -EAGAIN; | |
167 | goto out; | |
168 | do_interrupted: | |
169 | err = sock_intr_errno(*timeo_p); | |
170 | goto out; | |
171 | } | |
172 | ||
173 | EXPORT_SYMBOL(sk_stream_wait_memory); | |
174 | ||
175 | void sk_stream_rfree(struct sk_buff *skb) | |
176 | { | |
177 | struct sock *sk = skb->sk; | |
178 | ||
dc6de336 | 179 | skb_truesize_check(skb); |
1da177e4 LT |
180 | atomic_sub(skb->truesize, &sk->sk_rmem_alloc); |
181 | sk->sk_forward_alloc += skb->truesize; | |
182 | } | |
183 | ||
184 | EXPORT_SYMBOL(sk_stream_rfree); | |
185 | ||
186 | int 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 | } | |
194 | ||
195 | EXPORT_SYMBOL(sk_stream_error); | |
196 | ||
197 | void __sk_stream_mem_reclaim(struct sock *sk) | |
198 | { | |
a6f157a8 IM |
199 | atomic_sub(sk->sk_forward_alloc / SK_STREAM_MEM_QUANTUM, |
200 | sk->sk_prot->memory_allocated); | |
201 | sk->sk_forward_alloc &= SK_STREAM_MEM_QUANTUM - 1; | |
202 | if (*sk->sk_prot->memory_pressure && | |
203 | (atomic_read(sk->sk_prot->memory_allocated) < | |
204 | sk->sk_prot->sysctl_mem[0])) | |
205 | *sk->sk_prot->memory_pressure = 0; | |
1da177e4 LT |
206 | } |
207 | ||
208 | EXPORT_SYMBOL(__sk_stream_mem_reclaim); | |
209 | ||
210 | int sk_stream_mem_schedule(struct sock *sk, int size, int kind) | |
211 | { | |
212 | int amt = sk_stream_pages(size); | |
213 | ||
214 | sk->sk_forward_alloc += amt * SK_STREAM_MEM_QUANTUM; | |
215 | atomic_add(amt, sk->sk_prot->memory_allocated); | |
216 | ||
217 | /* Under limit. */ | |
218 | if (atomic_read(sk->sk_prot->memory_allocated) < sk->sk_prot->sysctl_mem[0]) { | |
219 | if (*sk->sk_prot->memory_pressure) | |
220 | *sk->sk_prot->memory_pressure = 0; | |
221 | return 1; | |
222 | } | |
223 | ||
224 | /* Over hard limit. */ | |
225 | if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[2]) { | |
226 | sk->sk_prot->enter_memory_pressure(); | |
227 | goto suppress_allocation; | |
228 | } | |
229 | ||
230 | /* Under pressure. */ | |
231 | if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[1]) | |
232 | sk->sk_prot->enter_memory_pressure(); | |
233 | ||
234 | if (kind) { | |
235 | if (atomic_read(&sk->sk_rmem_alloc) < sk->sk_prot->sysctl_rmem[0]) | |
236 | return 1; | |
237 | } else if (sk->sk_wmem_queued < sk->sk_prot->sysctl_wmem[0]) | |
238 | return 1; | |
239 | ||
240 | if (!*sk->sk_prot->memory_pressure || | |
241 | sk->sk_prot->sysctl_mem[2] > atomic_read(sk->sk_prot->sockets_allocated) * | |
242 | sk_stream_pages(sk->sk_wmem_queued + | |
243 | atomic_read(&sk->sk_rmem_alloc) + | |
244 | sk->sk_forward_alloc)) | |
245 | return 1; | |
246 | ||
247 | suppress_allocation: | |
248 | ||
249 | if (!kind) { | |
250 | sk_stream_moderate_sndbuf(sk); | |
251 | ||
252 | /* Fail only if socket is _under_ its sndbuf. | |
253 | * In this case we cannot block, so that we have to fail. | |
254 | */ | |
255 | if (sk->sk_wmem_queued + size >= sk->sk_sndbuf) | |
256 | return 1; | |
257 | } | |
258 | ||
259 | /* Alas. Undo changes. */ | |
260 | sk->sk_forward_alloc -= amt * SK_STREAM_MEM_QUANTUM; | |
261 | atomic_sub(amt, sk->sk_prot->memory_allocated); | |
262 | return 0; | |
263 | } | |
264 | ||
265 | EXPORT_SYMBOL(sk_stream_mem_schedule); | |
266 | ||
267 | void sk_stream_kill_queues(struct sock *sk) | |
268 | { | |
269 | /* First the read buffer. */ | |
270 | __skb_queue_purge(&sk->sk_receive_queue); | |
271 | ||
272 | /* Next, the error queue. */ | |
273 | __skb_queue_purge(&sk->sk_error_queue); | |
274 | ||
275 | /* Next, the write queue. */ | |
276 | BUG_TRAP(skb_queue_empty(&sk->sk_write_queue)); | |
277 | ||
278 | /* Account for returned memory. */ | |
279 | sk_stream_mem_reclaim(sk); | |
280 | ||
281 | BUG_TRAP(!sk->sk_wmem_queued); | |
282 | BUG_TRAP(!sk->sk_forward_alloc); | |
283 | ||
284 | /* It is _impossible_ for the backlog to contain anything | |
285 | * when we get here. All user references to this socket | |
286 | * have gone away, only the net layer knows can touch it. | |
287 | */ | |
288 | } | |
289 | ||
290 | EXPORT_SYMBOL(sk_stream_kill_queues); |