diff options
Diffstat (limited to 'net/decnet/dn_timer.c')
| -rw-r--r-- | net/decnet/dn_timer.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/net/decnet/dn_timer.c b/net/decnet/dn_timer.c new file mode 100644 index 000000000..aa4155875 --- /dev/null +++ b/net/decnet/dn_timer.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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 <linux/atomic.h> +#include <linux/jiffies.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(struct timer_list *t); + +void dn_start_slow_timer(struct sock *sk) +{ + timer_setup(&sk->sk_timer, dn_slow_timer, 0); + sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL); +} + +void dn_stop_slow_timer(struct sock *sk) +{ + sk_stop_timer(sk, &sk->sk_timer); +} + +static void dn_slow_timer(struct timer_list *t) +{ + struct sock *sk = from_timer(sk, t, sk_timer); + struct dn_scp *scp = DN_SK(sk); + + bh_lock_sock(sk); + + if (sock_owned_by_user(sk)) { + sk_reset_timer(sk, &sk->sk_timer, jiffies + HZ / 10); + 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 (time_after_eq(jiffies, scp->stamp + scp->keepalive)) + scp->keepalive_fxn(sk); + } + + sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL); +out: + bh_unlock_sock(sk); + sock_put(sk); +} |