Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 212 insertions, 0 deletions

diff --git a/net/core/stream.c b/net/core/stream.c
new file mode 100644
index 000000000..3d98774cf
--- /dev/null
+++ b/net/core/stream.c
@@ -0,0 +1,212 @@
+// 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) && 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, &current_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 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);