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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* TIMER - implementation of software timers for IP.
*
* Version: @(#)timer.c 1.0.7 05/25/93
*
* Authors: Ross Biro, <bir7@leland.Stanford.Edu>
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Corey Minyard <wf-rch!minyard@relay.EU.net>
* Fred Baumgarten, <dc6iq@insu1.etec.uni-karlsruhe.de>
* Florian La Roche, <flla@stud.uni-sb.de>
*
* Fixes:
* Alan Cox : To avoid destroying a wait queue as we use it
* we defer destruction until the destroy timer goes
* off.
* Alan Cox : Destroy socket doesn't write a status value to the
* socket buffer _AFTER_ freeing it! Also sock ensures
* the socket will get removed BEFORE this is called
* otherwise if the timer TIME_DESTROY occurs inside
* of inet_bh() with this socket being handled it goes
* BOOM! Have to stop timer going off if net_bh is
* active or the destroy causes crashes.
* Alan Cox : Cleaned up unused code.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <asm/system.h>
#include <linux/interrupt.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include "ip.h"
#include "protocol.h"
#include "tcp.h"
#include <linux/skbuff.h>
#include "sock.h"
#include "arp.h"
void delete_timer (struct sock *t)
{
unsigned long flags;
save_flags (flags);
cli();
t->timeout = 0;
del_timer (&t->timer);
restore_flags (flags);
}
void reset_timer (struct sock *t, int timeout, unsigned long len)
{
delete_timer (t);
t->timeout = timeout;
#if 1
/* FIXME: ??? */
if ((int) len < 0) /* prevent close to infinite timers. THEY _DO_ */
len = 3; /* happen (negative values ?) - don't ask me why ! -FB */
#endif
t->timer.expires = len;
add_timer (&t->timer);
}
/*
* Now we will only be called whenever we need to do
* something, but we must be sure to process all of the
* sockets that need it.
*/
void net_timer (unsigned long data)
{
struct sock *sk = (struct sock*)data;
int why = sk->timeout;
/*
* only process if socket is not in use
*/
cli();
if (sk->inuse || in_bh)
{
sk->timer.expires = 10;
add_timer(&sk->timer);
sti();
return;
}
sk->inuse = 1;
sti();
/* Always see if we need to send an ack. */
if (sk->ack_backlog && !sk->zapped)
{
sk->prot->read_wakeup (sk);
if (! sk->dead)
sk->data_ready(sk,0);
}
/* Now we need to figure out why the socket was on the timer. */
switch (why)
{
case TIME_DONE:
if (! sk->dead || sk->state != TCP_CLOSE)
{
printk ("non dead socket in time_done\n");
release_sock (sk);
break;
}
destroy_sock (sk);
break;
case TIME_DESTROY:
/*
* We've waited for a while for all the memory associated with
* the socket to be freed.
*/
if(sk->wmem_alloc!=0 || sk->rmem_alloc!=0)
{
sk->wmem_alloc++; /* So it DOESN'T go away */
destroy_sock (sk);
sk->wmem_alloc--; /* Might now have hit 0 - fall through and do it again if so */
sk->inuse = 0; /* This will be ok, the destroy won't totally work */
}
if(sk->wmem_alloc==0 && sk->rmem_alloc==0)
destroy_sock(sk); /* Socket gone, DON'T update sk->inuse! */
break;
case TIME_CLOSE:
/* We've waited long enough, close the socket. */
sk->state = TCP_CLOSE;
delete_timer (sk);
/* Kill the ARP entry in case the hardware has changed. */
arp_destroy (sk->daddr, 0);
if (!sk->dead)
sk->state_change(sk);
sk->shutdown = SHUTDOWN_MASK;
reset_timer (sk, TIME_DESTROY, TCP_DONE_TIME);
release_sock (sk);
break;
case TIME_PROBE0:
tcp_send_probe0(sk);
release_sock (sk);
break;
case TIME_WRITE: /* try to retransmit. */
/* It could be we got here because we needed to send an ack.
* So we need to check for that.
*/
{
struct sk_buff *skb;
unsigned long flags;
save_flags(flags);
cli();
skb = sk->send_head;
if (!skb)
{
restore_flags(flags);
}
else
{
if (jiffies < skb->when + sk->rto)
{
reset_timer (sk, TIME_WRITE, skb->when + sk->rto - jiffies);
restore_flags(flags);
release_sock (sk);
break;
}
restore_flags(flags);
/* printk("timer: seq %d retrans %d out %d cong %d\n", sk->send_head->h.seq,
sk->retransmits, sk->packets_out, sk->cong_window); */
sk->prot->retransmit (sk, 0);
if ((sk->state == TCP_ESTABLISHED && sk->retransmits && !(sk->retransmits & 7))
|| (sk->state != TCP_ESTABLISHED && sk->retransmits > TCP_RETR1))
{
arp_destroy (sk->daddr, 0);
ip_route_check (sk->daddr);
}
if (sk->state != TCP_ESTABLISHED && sk->retransmits > TCP_RETR2)
{
sk->err = ETIMEDOUT;
if (sk->state == TCP_FIN_WAIT1 || sk->state == TCP_FIN_WAIT2 || sk->state == TCP_CLOSING)
{
sk->state = TCP_TIME_WAIT;
reset_timer (sk, TIME_CLOSE, TCP_TIMEWAIT_LEN);
}
else
{
sk->prot->close (sk, 1);
break;
}
}
}
release_sock (sk);
break;
}
case TIME_KEEPOPEN:
/*
* this reset_timer() call is a hack, this is not
* how KEEPOPEN is supposed to work.
*/
reset_timer (sk, TIME_KEEPOPEN, TCP_TIMEOUT_LEN);
/* Send something to keep the connection open. */
if (sk->prot->write_wakeup)
sk->prot->write_wakeup (sk);
sk->retransmits++;
if (sk->shutdown == SHUTDOWN_MASK)
{
sk->prot->close (sk, 1);
sk->state = TCP_CLOSE;
}
if ((sk->state == TCP_ESTABLISHED && sk->retransmits && !(sk->retransmits & 7))
|| (sk->state != TCP_ESTABLISHED && sk->retransmits > TCP_RETR1))
{
arp_destroy (sk->daddr, 0);
ip_route_check (sk->daddr);
release_sock (sk);
break;
}
if (sk->state != TCP_ESTABLISHED && sk->retransmits > TCP_RETR2)
{
arp_destroy (sk->daddr, 0);
sk->err = ETIMEDOUT;
if (sk->state == TCP_FIN_WAIT1 || sk->state == TCP_FIN_WAIT2)
{
sk->state = TCP_TIME_WAIT;
if (!sk->dead)
sk->state_change(sk);
release_sock (sk);
}
else
{
sk->prot->close (sk, 1);
}
break;
}
release_sock (sk);
break;
default:
printk ("net_timer: timer expired - reason unknown\n");
release_sock (sk);
break;
}
}
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