blob: d1d7decf70b0087af2de9358049e5e43ed46d326 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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.
Pavel Pisa4dc3b162005-05-01 08:59:25 -070024 * @sk: socket
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 *
26 * FIXME: write proper description
27 */
28void 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
42EXPORT_SYMBOL(sk_stream_write_space);
43
44/**
45 * sk_stream_wait_connect - Wait for a socket to get into the connected state
Pavel Pisa4dc3b162005-05-01 08:59:25 -070046 * @sk: sock to wait on
47 * @timeo_p: for how long to wait
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 *
49 * Must be called with the socket locked.
50 */
51int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
52{
53 struct task_struct *tsk = current;
54 DEFINE_WAIT(wait);
Herbert Xu6151b312005-11-04 09:56:56 +110055 int done;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Herbert Xu6151b312005-11-04 09:56:56 +110057 do {
Benjamin LaHaisec1cbe4b2005-12-13 23:22:19 -080058 int err = sock_error(sk);
59 if (err)
60 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 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++;
Herbert Xu6151b312005-11-04 09:56:56 +110070 done = sk_wait_event(sk, timeo_p,
Benjamin LaHaisec1cbe4b2005-12-13 23:22:19 -080071 !sk->sk_err &&
Herbert Xu6151b312005-11-04 09:56:56 +110072 !((1 << sk->sk_state) &
73 ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)));
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 finish_wait(sk->sk_sleep, &wait);
75 sk->sk_write_pending--;
Herbert Xu6151b312005-11-04 09:56:56 +110076 } while (!done);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 return 0;
78}
79
80EXPORT_SYMBOL(sk_stream_wait_connect);
81
82/**
83 * sk_stream_closing - Return 1 if we still have things to send in our buffers.
Pavel Pisa4dc3b162005-05-01 08:59:25 -070084 * @sk: socket to verify
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 */
86static 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
92void 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
108EXPORT_SYMBOL(sk_stream_wait_close);
109
110/**
111 * sk_stream_wait_memory - Wait for more memory for a socket
Pavel Pisa4dc3b162005-05-01 08:59:25 -0700112 * @sk: socket to wait for memory
113 * @timeo_p: for how long
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 */
115int 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++;
Benjamin LaHaisec1cbe4b2005-12-13 23:22:19 -0800142 sk_wait_event(sk, &current_timeo, !sk->sk_err &&
143 !(sk->sk_shutdown & SEND_SHUTDOWN) &&
144 sk_stream_memory_free(sk) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 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 }
158out:
159 finish_wait(sk->sk_sleep, &wait);
160 return err;
161
162do_error:
163 err = -EPIPE;
164 goto out;
165do_nonblock:
166 err = -EAGAIN;
167 goto out;
168do_interrupted:
169 err = sock_intr_errno(*timeo_p);
170 goto out;
171}
172
173EXPORT_SYMBOL(sk_stream_wait_memory);
174
175void sk_stream_rfree(struct sk_buff *skb)
176{
177 struct sock *sk = skb->sk;
178
David S. Millerdc6de332006-04-20 00:10:50 -0700179 skb_truesize_check(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
181 sk->sk_forward_alloc += skb->truesize;
182}
183
184EXPORT_SYMBOL(sk_stream_rfree);
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}
194
195EXPORT_SYMBOL(sk_stream_error);
196
197void __sk_stream_mem_reclaim(struct sock *sk)
198{
Ian McDonalda6f157a2006-07-12 17:58:53 -0700199 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206}
207
208EXPORT_SYMBOL(__sk_stream_mem_reclaim);
209
210int 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
247suppress_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
265EXPORT_SYMBOL(sk_stream_mem_schedule);
266
267void 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
290EXPORT_SYMBOL(sk_stream_kill_queues);