1 files changed, 109 insertions, 0 deletions
diff --git a/net/decnet/dn_timer.c b/net/decnet/dn_timer.c
new file mode 100644
index 0000000..0982571
--- /dev/null
+++ b/net/decnet/dn_timer.c
@@ -0,0 +1,109 @@
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Socket Timer Functions
+ *
+ * Author:      Steve Whitehouse <SteveW@ACM.org>
+ *
+ *
+ * Changes:
+ *       Steve Whitehouse      : Made keepalive timer part of the same
+ *                               timer idea.
+ *       Steve Whitehouse      : Added checks for sk->sock_readers
+ *       David S. Miller       : New socket locking
+ *       Steve Whitehouse      : Timer grabs socket ref.
+ */
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <net/sock.h>
+#include <asm/atomic.h>
+#include <net/flow.h>
+#include <net/dn.h>
+
+/*
+ * Slow timer is for everything else (n * 500mS)
+ */
+
+#define SLOW_INTERVAL (HZ/2)
+
+static void dn_slow_timer(unsigned long arg);
+
+void dn_start_slow_timer(struct sock *sk)
+{
+	sk->sk_timer.expires	= jiffies + SLOW_INTERVAL;
+	sk->sk_timer.function	= dn_slow_timer;
+	sk->sk_timer.data	= (unsigned long)sk;
+
+	add_timer(&sk->sk_timer);
+}
+
+void dn_stop_slow_timer(struct sock *sk)
+{
+	del_timer(&sk->sk_timer);
+}
+
+static void dn_slow_timer(unsigned long arg)
+{
+	struct sock *sk = (struct sock *)arg;
+	struct dn_scp *scp = DN_SK(sk);
+
+	sock_hold(sk);
+	bh_lock_sock(sk);
+
+	if (sock_owned_by_user(sk)) {
+		sk->sk_timer.expires = jiffies + HZ / 10;
+		add_timer(&sk->sk_timer);
+		goto out;
+	}
+
+	/*
+	 * The persist timer is the standard slow timer used for retransmits
+	 * in both connection establishment and disconnection as well as
+	 * in the RUN state. The different states are catered for by changing
+	 * the function pointer in the socket. Setting the timer to a value
+	 * of zero turns it off. We allow the persist_fxn to turn the
+	 * timer off in a permant way by returning non-zero, so that
+	 * timer based routines may remove sockets. This is why we have a
+	 * sock_hold()/sock_put() around the timer to prevent the socket
+	 * going away in the middle.
+	 */
+	if (scp->persist && scp->persist_fxn) {
+		if (scp->persist <= SLOW_INTERVAL) {
+			scp->persist = 0;
+
+			if (scp->persist_fxn(sk))
+				goto out;
+		} else {
+			scp->persist -= SLOW_INTERVAL;
+		}
+	}
+
+	/*
+	 * Check for keepalive timeout. After the other timer 'cos if
+	 * the previous timer caused a retransmit, we don't need to
+	 * do this. scp->stamp is the last time that we sent a packet.
+	 * The keepalive function sends a link service packet to the
+	 * other end. If it remains unacknowledged, the standard
+	 * socket timers will eventually shut the socket down. Each
+	 * time we do this, scp->stamp will be updated, thus
+	 * we won't try and send another until scp->keepalive has passed
+	 * since the last successful transmission.
+	 */
+	if (scp->keepalive && scp->keepalive_fxn && (scp->state == DN_RUN)) {
+		if ((jiffies - scp->stamp) >= scp->keepalive)
+			scp->keepalive_fxn(sk);
+	}
+
+	sk->sk_timer.expires = jiffies + SLOW_INTERVAL;
+
+	add_timer(&sk->sk_timer);
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}