11da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 21da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * DECnet An implementation of the DECnet protocol suite for the LINUX 31da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * operating system. DECnet is implemented using the BSD Socket 41da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * interface as the means of communication with the user level. 51da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 61da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * DECnet Socket Timer Functions 71da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 81da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Author: Steve Whitehouse <SteveW@ACM.org> 91da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * 111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Changes: 121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Steve Whitehouse : Made keepalive timer part of the same 131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * timer idea. 141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Steve Whitehouse : Added checks for sk->sock_readers 151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * David S. Miller : New socket locking 161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Steve Whitehouse : Timer grabs socket ref. 171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/net.h> 191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/socket.h> 201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/skbuff.h> 211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/netdevice.h> 221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/timer.h> 231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/spinlock.h> 241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <net/sock.h> 2560063497a95e716c9a689af3be2687d261f115b4Arun Sharma#include <linux/atomic.h> 268b1b1eb521004cec2518307c22dba8f4bff1c2bfHimangi Saraogi#include <linux/jiffies.h> 271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <net/flow.h> 281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <net/dn.h> 291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/* 311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Slow timer is for everything else (n * 500mS) 321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#define SLOW_INTERVAL (HZ/2) 351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void dn_slow_timer(unsigned long arg); 371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsvoid dn_start_slow_timer(struct sock *sk) 391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 408a6e77d5209e459a9ec5c268c39800c06cd1dc86Eric Dumazet setup_timer(&sk->sk_timer, dn_slow_timer, (unsigned long)sk); 418a6e77d5209e459a9ec5c268c39800c06cd1dc86Eric Dumazet sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL); 421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsvoid dn_stop_slow_timer(struct sock *sk) 451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 468a6e77d5209e459a9ec5c268c39800c06cd1dc86Eric Dumazet sk_stop_timer(sk, &sk->sk_timer); 471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void dn_slow_timer(unsigned long arg) 501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{ 511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct sock *sk = (struct sock *)arg; 521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds struct dn_scp *scp = DN_SK(sk); 531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds bh_lock_sock(sk); 551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (sock_owned_by_user(sk)) { 578a6e77d5209e459a9ec5c268c39800c06cd1dc86Eric Dumazet sk_reset_timer(sk, &sk->sk_timer, jiffies + HZ / 10); 581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * The persist timer is the standard slow timer used for retransmits 631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * in both connection establishment and disconnection as well as 641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * in the RUN state. The different states are catered for by changing 651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * the function pointer in the socket. Setting the timer to a value 661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * of zero turns it off. We allow the persist_fxn to turn the 671da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * timer off in a permant way by returning non-zero, so that 681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * timer based routines may remove sockets. This is why we have a 691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * sock_hold()/sock_put() around the timer to prevent the socket 701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * going away in the middle. 711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (scp->persist && scp->persist_fxn) { 731da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (scp->persist <= SLOW_INTERVAL) { 741da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds scp->persist = 0; 751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (scp->persist_fxn(sk)) 771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds goto out; 781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } else { 791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds scp->persist -= SLOW_INTERVAL; 801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds /* 841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Check for keepalive timeout. After the other timer 'cos if 851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * the previous timer caused a retransmit, we don't need to 861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * do this. scp->stamp is the last time that we sent a packet. 871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * The keepalive function sends a link service packet to the 881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * other end. If it remains unacknowledged, the standard 891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * socket timers will eventually shut the socket down. Each 901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * time we do this, scp->stamp will be updated, thus 911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * we won't try and send another until scp->keepalive has passed 921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * since the last successful transmission. 931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */ 941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds if (scp->keepalive && scp->keepalive_fxn && (scp->state == DN_RUN)) { 958b1b1eb521004cec2518307c22dba8f4bff1c2bfHimangi Saraogi if (time_after_eq(jiffies, scp->stamp + scp->keepalive)) 961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds scp->keepalive_fxn(sk); 971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds } 981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 998a6e77d5209e459a9ec5c268c39800c06cd1dc86Eric Dumazet sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL); 1001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsout: 1011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds bh_unlock_sock(sk); 1021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds sock_put(sk); 1031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds} 104