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-rw-r--r--net/decnet/dn_timer.c109
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);
+}
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