Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * 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);

}