diff options
Diffstat (limited to 'net/core/stream.c')
| -rw-r--r-- | net/core/stream.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/net/core/stream.c b/net/core/stream.c new file mode 100644 index 000000000..422ee97e4 --- /dev/null +++ b/net/core/stream.c @@ -0,0 +1,218 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SUCS NET3: + * + * Generic stream handling routines. These are generic for most + * protocols. Even IP. Tonight 8-). + * This is used because TCP, LLC (others too) layer all have mostly + * identical sendmsg() and recvmsg() code. + * So we (will) share it here. + * + * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br> + * (from old tcp.c code) + * Alan Cox <alan@lxorguk.ukuu.org.uk> (Borrowed comments 8-)) + */ + +#include <linux/module.h> +#include <linux/sched/signal.h> +#include <linux/net.h> +#include <linux/signal.h> +#include <linux/tcp.h> +#include <linux/wait.h> +#include <net/sock.h> + +/** + * sk_stream_write_space - stream socket write_space callback. + * @sk: socket + * + * FIXME: write proper description + */ +void sk_stream_write_space(struct sock *sk) +{ + struct socket *sock = sk->sk_socket; + struct socket_wq *wq; + + if (__sk_stream_is_writeable(sk, 1) && sock) { + clear_bit(SOCK_NOSPACE, &sock->flags); + + rcu_read_lock(); + wq = rcu_dereference(sk->sk_wq); + if (skwq_has_sleeper(wq)) + wake_up_interruptible_poll(&wq->wait, EPOLLOUT | + EPOLLWRNORM | EPOLLWRBAND); + if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN)) + sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT); + rcu_read_unlock(); + } +} + +/** + * sk_stream_wait_connect - Wait for a socket to get into the connected state + * @sk: sock to wait on + * @timeo_p: for how long to wait + * + * Must be called with the socket locked. + */ +int sk_stream_wait_connect(struct sock *sk, long *timeo_p) +{ + DEFINE_WAIT_FUNC(wait, woken_wake_function); + struct task_struct *tsk = current; + int done; + + do { + int err = sock_error(sk); + if (err) + return err; + if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) + return -EPIPE; + if (!*timeo_p) + return -EAGAIN; + if (signal_pending(tsk)) + return sock_intr_errno(*timeo_p); + + add_wait_queue(sk_sleep(sk), &wait); + sk->sk_write_pending++; + done = sk_wait_event(sk, timeo_p, + !READ_ONCE(sk->sk_err) && + !((1 << READ_ONCE(sk->sk_state)) & + ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)), &wait); + remove_wait_queue(sk_sleep(sk), &wait); + sk->sk_write_pending--; + } while (!done); + return 0; +} +EXPORT_SYMBOL(sk_stream_wait_connect); + +/** + * sk_stream_closing - Return 1 if we still have things to send in our buffers. + * @sk: socket to verify + */ +static int sk_stream_closing(const struct sock *sk) +{ + return (1 << READ_ONCE(sk->sk_state)) & + (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK); +} + +void sk_stream_wait_close(struct sock *sk, long timeout) +{ + if (timeout) { + DEFINE_WAIT_FUNC(wait, woken_wake_function); + + add_wait_queue(sk_sleep(sk), &wait); + + do { + if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk), &wait)) + break; + } while (!signal_pending(current) && timeout); + + remove_wait_queue(sk_sleep(sk), &wait); + } +} +EXPORT_SYMBOL(sk_stream_wait_close); + +/** + * sk_stream_wait_memory - Wait for more memory for a socket + * @sk: socket to wait for memory + * @timeo_p: for how long + */ +int sk_stream_wait_memory(struct sock *sk, long *timeo_p) +{ + int err = 0; + long vm_wait = 0; + long current_timeo = *timeo_p; + DEFINE_WAIT_FUNC(wait, woken_wake_function); + + if (sk_stream_memory_free(sk)) + current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2; + + add_wait_queue(sk_sleep(sk), &wait); + + while (1) { + sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk); + + if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) + goto do_error; + if (!*timeo_p) + goto do_eagain; + if (signal_pending(current)) + goto do_interrupted; + sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); + if (sk_stream_memory_free(sk) && !vm_wait) + break; + + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); + sk->sk_write_pending++; + sk_wait_event(sk, ¤t_timeo, READ_ONCE(sk->sk_err) || + (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) || + (sk_stream_memory_free(sk) && + !vm_wait), &wait); + sk->sk_write_pending--; + + if (vm_wait) { + vm_wait -= current_timeo; + current_timeo = *timeo_p; + if (current_timeo != MAX_SCHEDULE_TIMEOUT && + (current_timeo -= vm_wait) < 0) + current_timeo = 0; + vm_wait = 0; + } + *timeo_p = current_timeo; + } +out: + if (!sock_flag(sk, SOCK_DEAD)) + remove_wait_queue(sk_sleep(sk), &wait); + return err; + +do_error: + err = -EPIPE; + goto out; +do_eagain: + /* Make sure that whenever EAGAIN is returned, EPOLLOUT event can + * be generated later. + * When TCP receives ACK packets that make room, tcp_check_space() + * only calls tcp_new_space() if SOCK_NOSPACE is set. + */ + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); + err = -EAGAIN; + goto out; +do_interrupted: + err = sock_intr_errno(*timeo_p); + goto out; +} +EXPORT_SYMBOL(sk_stream_wait_memory); + +int sk_stream_error(struct sock *sk, int flags, int err) +{ + if (err == -EPIPE) + err = sock_error(sk) ? : -EPIPE; + if (err == -EPIPE && !(flags & MSG_NOSIGNAL)) + send_sig(SIGPIPE, current, 0); + return err; +} +EXPORT_SYMBOL(sk_stream_error); + +void sk_stream_kill_queues(struct sock *sk) +{ + /* First the read buffer. */ + __skb_queue_purge(&sk->sk_receive_queue); + + /* Next, the error queue. + * We need to use queue lock, because other threads might + * add packets to the queue without socket lock being held. + */ + skb_queue_purge(&sk->sk_error_queue); + + /* Next, the write queue. */ + WARN_ON(!skb_queue_empty(&sk->sk_write_queue)); + + /* Account for returned memory. */ + sk_mem_reclaim(sk); + + WARN_ON(sk->sk_wmem_queued); + + /* It is _impossible_ for the backlog to contain anything + * when we get here. All user references to this socket + * have gone away, only the net layer knows can touch it. + */ +} +EXPORT_SYMBOL(sk_stream_kill_queues); |