netfilter: have ip*t REJECT set the sock err when an icmp is to be sent
[linux-3.10.git] / net / core / stream.c
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, &current_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);