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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224// 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: pointer to the socket structure * * This function is invoked when there's space available in the socket's * send buffer for writing. It first checks if the socket is writable, * clears the SOCK_NOSPACE flag indicating that memory for writing * is now available, wakes up any processes waiting for write operations * and sends asynchronous notifications if needed. */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 done < 0 ? done : 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); }}
/** * 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 ret, 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 = get_random_u32_below(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++; ret = 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 (ret < 0) goto do_error;
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_ONCE(!skb_queue_empty(&sk->sk_write_queue));
/* Account for returned memory. */ sk_mem_reclaim_final(sk);
WARN_ON_ONCE(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);