English
- /*
- * 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/dn.h>
- /*
- * Fast timer is for delayed acks (200mS max)
- * Slow timer is for everything else (n * 500mS)
- */
- #define FAST_INTERVAL (HZ/5)
- #define SLOW_INTERVAL (HZ/2)
- static void dn_slow_timer(unsigned long arg);
- void dn_start_slow_timer(struct sock *sk)
- {
- sk->timer.expires = jiffies + SLOW_INTERVAL;
- sk->timer.function = dn_slow_timer;
- sk->timer.data = (unsigned long)sk;
- add_timer(&sk->timer);
- }
- void dn_stop_slow_timer(struct sock *sk)
- {
- del_timer(&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 (sk->lock.users != 0) {
- sk->timer.expires = jiffies + HZ / 10;
- add_timer(&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->timer.expires = jiffies + SLOW_INTERVAL;
- add_timer(&sk->timer);
- out:
- bh_unlock_sock(sk);
- sock_put(sk);
- }
- static void dn_fast_timer(unsigned long arg)
- {
- struct sock *sk = (struct sock *)arg;
- struct dn_scp *scp = DN_SK(sk);
- bh_lock_sock(sk);
- if (sk->lock.users != 0) {
- scp->delack_timer.expires = jiffies + HZ / 20;
- add_timer(&scp->delack_timer);
- goto out;
- }
- scp->delack_pending = 0;
- if (scp->delack_fxn)
- scp->delack_fxn(sk);
- out:
- bh_unlock_sock(sk);
- }
- void dn_start_fast_timer(struct sock *sk)
- {
- struct dn_scp *scp = DN_SK(sk);
- if (!scp->delack_pending) {
- scp->delack_pending = 1;
- init_timer(&scp->delack_timer);
- scp->delack_timer.expires = jiffies + FAST_INTERVAL;
- scp->delack_timer.data = (unsigned long)sk;
- scp->delack_timer.function = dn_fast_timer;
- add_timer(&scp->delack_timer);
- }
- }
- void dn_stop_fast_timer(struct sock *sk)
- {
- struct dn_scp *scp = DN_SK(sk);
- if (scp->delack_pending) {
- scp->delack_pending = 0;
- del_timer(&scp->delack_timer);
- }
- }
