net/ipv4/timer.c

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 1 /*
 2  * INET An implementation of the TCP/IP protocol suite for the LINUX
 3  * operating system. INET is implemented using the BSD Socket
 4  * interface as the means of communication with the user level.
 5  *
 6  * TIMER - implementation of software timers for IP.
 7  *
 8  * Version: $Id: timer.c,v 1.10 1998/03/13 08:02:18 davem Exp $
 9  *
 10  * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
 11  * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 12  * Corey Minyard <wf-rch!minyard@relay.EU.net>
 13  * Fred Baumgarten, <dc6iq@insu1.etec.uni-karlsruhe.de>
 14  * Florian La Roche, <flla@stud.uni-sb.de>
 15  *
 16  * Fixes:
 17  * Alan Cox : To avoid destroying a wait queue as we use it
 18  * we defer destruction until the destroy timer goes
 19  * off.
 20  * Alan Cox : Destroy socket doesn't write a status value to the
 21  * socket buffer _AFTER_ freeing it! Also sock ensures
 22  * the socket will get removed BEFORE this is called
 23  * otherwise if the timer TIME_DESTROY occurs inside
 24  * of inet_bh() with this socket being handled it goes
 25  * BOOM! Have to stop timer going off if net_bh is
 26  * active or the destroy causes crashes.
 27  * Alan Cox : Cleaned up unused code.
 28  *
 29  * This program is free software; you can redistribute it and/or
 30  * modify it under the terms of the GNU General Public License
 31  * as published by the Free Software Foundation; either version
 32  * 2 of the License, or (at your option) any later version.
 33  */
 34
 35 #include <linux/types.h>
 36 #include <linux/errno.h>
 37 #include <linux/socket.h>
 38 #include <linux/in.h>
 39 #include <linux/kernel.h>
 40 #include <linux/sched.h>
 41 #include <linux/timer.h>
 42 #include <asm/system.h>
 43 #include <linux/interrupt.h>
 44 #include <linux/inet.h>
 45 #include <linux/netdevice.h>
 46 #include <net/ip.h>
 47 #include <net/protocol.h>
 48 #include <net/tcp.h>
 49 #include <linux/skbuff.h>
 50 #include <net/sock.h>
 51 #include <net/arp.h>
 52
 53 voidnet_delete_timer(struct sock *t)
 54 {
 55 if(t->timer.prev)
 56 del_timer(&t->timer);
 57  t->timeout =0;
 58 }
 59
 60 voidnet_reset_timer(struct sock *t,int timeout,unsigned long len)
 61 {
 62 net_delete_timer(t);
 63  t->timeout = timeout;
 64  t->timer.expires = jiffies+len;
 65 add_timer(&t->timer);
 66 }
 67
 68 /* Now we will only be called whenever we need to do
 69  * something, but we must be sure to process all of the
 70  * sockets that need it.
 71  */
 72 voidnet_timer(unsigned long data)
 73 {
 74 struct sock *sk = (struct sock*)data;
 75 int why = sk->timeout;
 76
 77 /* Only process if socket is not in use. */
 78 if(sk->sock_readers) {
 79  sk->timer.expires = jiffies+HZ;
 80 add_timer(&sk->timer);
 81 return;
 82 }
 83
 84 /* Always see if we need to send an ack. */
 85 if(sk->tp_pinfo.af_tcp.delayed_acks && !sk->zapped) {
 86  sk->prot->read_wakeup(sk);
 87 if(!sk->dead)
 88  sk->data_ready(sk,0);
 89 }
 90
 91 /* Now we need to figure out why the socket was on the timer. */
 92 switch(why) {
 93 case TIME_DONE:
 94 /* If the socket hasn't been closed off, re-try a bit later. */
 95 if(!sk->dead) {
 96 net_reset_timer(sk, TIME_DONE, TCP_DONE_TIME);
 97 break;
 98 }
 99
 100 if(sk->state != TCP_CLOSE) {
 101 printk(KERN_DEBUG "non CLOSE socket in time_done\n");
 102 break;
 103 }
 104 destroy_sock(sk);
 105 break;
 106
 107 case TIME_DESTROY:
 108 /* We've waited for a while for all the memory associated with
 109  * the socket to be freed.
 110  */
 111 destroy_sock(sk);
 112 break;
 113
 114 case TIME_CLOSE:
 115 /* We've waited long enough, close the socket. */
 116  sk->state = TCP_CLOSE;
 117 net_delete_timer(sk);
 118 if(!sk->dead)
 119  sk->state_change(sk);
 120  sk->shutdown = SHUTDOWN_MASK;
 121 net_reset_timer(sk, TIME_DONE, TCP_DONE_TIME);
 122 break;
 123
 124 default:
 125 /* I want to see these... */
 126 printk("net_timer: timer expired - reason %d is unknown\n", why);
 127 break;
 128 }
 129 }
 130