// 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, !sk->sk_err && !((1 << 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 inline int sk_stream_closing(struct sock *sk) { return (1 << 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, sk->sk_err || (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: 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. */ __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); WARN_ON(sk->sk_forward_alloc); /* 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);