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-rw-r--r--net/core/stream.c287
1 files changed, 287 insertions, 0 deletions
diff --git a/net/core/stream.c b/net/core/stream.c
new file mode 100644
index 000000000000..1e27a57b5a97
--- /dev/null
+++ b/net/core/stream.c
@@ -0,0 +1,287 @@
+/*
+ * 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@redhat.com> (Borrowed comments 8-))
+ */
+
+#include <linux/module.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;
+
+ if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) && sock) {
+ clear_bit(SOCK_NOSPACE, &sock->flags);
+
+ if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
+ wake_up_interruptible(sk->sk_sleep);
+ if (sock->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
+ sock_wake_async(sock, 2, POLL_OUT);
+ }
+}
+
+EXPORT_SYMBOL(sk_stream_write_space);
+
+/**
+ * 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)
+{
+ struct task_struct *tsk = current;
+ DEFINE_WAIT(wait);
+
+ while (1) {
+ if (sk->sk_err)
+ return sock_error(sk);
+ 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);
+
+ prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+ sk->sk_write_pending++;
+ if (sk_wait_event(sk, timeo_p,
+ !((1 << sk->sk_state) &
+ ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))))
+ break;
+ finish_wait(sk->sk_sleep, &wait);
+ sk->sk_write_pending--;
+ }
+ 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(wait);
+
+ do {
+ prepare_to_wait(sk->sk_sleep, &wait,
+ TASK_INTERRUPTIBLE);
+ if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk)))
+ break;
+ } while (!signal_pending(current) && timeout);
+
+ finish_wait(sk->sk_sleep, &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(wait);
+
+ if (sk_stream_memory_free(sk))
+ current_timeo = vm_wait = (net_random() % (HZ / 5)) + 2;
+
+ while (1) {
+ set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+
+ prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+
+ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+ goto do_error;
+ if (!*timeo_p)
+ goto do_nonblock;
+ if (signal_pending(current))
+ goto do_interrupted;
+ clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+ 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_stream_memory_free(sk) &&
+ vm_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:
+ finish_wait(sk->sk_sleep, &wait);
+ return err;
+
+do_error:
+ err = -EPIPE;
+ goto out;
+do_nonblock:
+ err = -EAGAIN;
+ goto out;
+do_interrupted:
+ err = sock_intr_errno(*timeo_p);
+ goto out;
+}
+
+EXPORT_SYMBOL(sk_stream_wait_memory);
+
+void sk_stream_rfree(struct sk_buff *skb)
+{
+ struct sock *sk = skb->sk;
+
+ atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
+ sk->sk_forward_alloc += skb->truesize;
+}
+
+EXPORT_SYMBOL(sk_stream_rfree);
+
+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_mem_reclaim(struct sock *sk)
+{
+ if (sk->sk_forward_alloc >= SK_STREAM_MEM_QUANTUM) {
+ atomic_sub(sk->sk_forward_alloc / SK_STREAM_MEM_QUANTUM,
+ sk->sk_prot->memory_allocated);
+ sk->sk_forward_alloc &= SK_STREAM_MEM_QUANTUM - 1;
+ if (*sk->sk_prot->memory_pressure &&
+ (atomic_read(sk->sk_prot->memory_allocated) <
+ sk->sk_prot->sysctl_mem[0]))
+ *sk->sk_prot->memory_pressure = 0;
+ }
+}
+
+EXPORT_SYMBOL(__sk_stream_mem_reclaim);
+
+int sk_stream_mem_schedule(struct sock *sk, int size, int kind)
+{
+ int amt = sk_stream_pages(size);
+
+ sk->sk_forward_alloc += amt * SK_STREAM_MEM_QUANTUM;
+ atomic_add(amt, sk->sk_prot->memory_allocated);
+
+ /* Under limit. */
+ if (atomic_read(sk->sk_prot->memory_allocated) < sk->sk_prot->sysctl_mem[0]) {
+ if (*sk->sk_prot->memory_pressure)
+ *sk->sk_prot->memory_pressure = 0;
+ return 1;
+ }
+
+ /* Over hard limit. */
+ if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[2]) {
+ sk->sk_prot->enter_memory_pressure();
+ goto suppress_allocation;
+ }
+
+ /* Under pressure. */
+ if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[1])
+ sk->sk_prot->enter_memory_pressure();
+
+ if (kind) {
+ if (atomic_read(&sk->sk_rmem_alloc) < sk->sk_prot->sysctl_rmem[0])
+ return 1;
+ } else if (sk->sk_wmem_queued < sk->sk_prot->sysctl_wmem[0])
+ return 1;
+
+ if (!*sk->sk_prot->memory_pressure ||
+ sk->sk_prot->sysctl_mem[2] > atomic_read(sk->sk_prot->sockets_allocated) *
+ sk_stream_pages(sk->sk_wmem_queued +
+ atomic_read(&sk->sk_rmem_alloc) +
+ sk->sk_forward_alloc))
+ return 1;
+
+suppress_allocation:
+
+ if (!kind) {
+ sk_stream_moderate_sndbuf(sk);
+
+ /* Fail only if socket is _under_ its sndbuf.
+ * In this case we cannot block, so that we have to fail.
+ */
+ if (sk->sk_wmem_queued + size >= sk->sk_sndbuf)
+ return 1;
+ }
+
+ /* Alas. Undo changes. */
+ sk->sk_forward_alloc -= amt * SK_STREAM_MEM_QUANTUM;
+ atomic_sub(amt, sk->sk_prot->memory_allocated);
+ return 0;
+}
+
+EXPORT_SYMBOL(sk_stream_mem_schedule);
+
+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. */
+ BUG_TRAP(skb_queue_empty(&sk->sk_write_queue));
+
+ /* Account for returned memory. */
+ sk_stream_mem_reclaim(sk);
+
+ BUG_TRAP(!sk->sk_wmem_queued);
+ BUG_TRAP(!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);
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-17 11:41:22 +0000