| // 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); |