net/ipv4/timer.c

/* */
This source file includes following definitions.
delete_timer
reset_timer
net_timer
   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:     @(#)timer.c     1.0.7   05/25/93
   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 void delete_timer (struct sock *t)
     /*  */
  54 {
  55         unsigned long flags;
  56 
  57         save_flags (flags);
  58         cli();
  59 
  60         t->timeout = 0;
  61         del_timer (&t->timer);
  62 
  63         restore_flags (flags);
  64 }
  65 
  66 void reset_timer (struct sock *t, int timeout, unsigned long len)
     /*  */
  67 {
  68         delete_timer (t);
  69         t->timeout = timeout;
  70 #if 1
  71   /* FIXME: ??? */
  72         if ((int) len < 0)      /* prevent close to infinite timers. THEY _DO_ */
  73                 len = 3;        /* happen (negative values ?) - don't ask me why ! -FB */
  74 #endif
  75         t->timer.expires = jiffies+len;
  76         add_timer (&t->timer);
  77 }
  78 
  79 
  80 /*
  81  *      Now we will only be called whenever we need to do
  82  *      something, but we must be sure to process all of the
  83  *      sockets that need it.
  84  */
  85 
  86 void net_timer (unsigned long data)
     /*  */
  87 {
  88         struct sock *sk = (struct sock*)data;
  89         int why = sk->timeout;
  90 
  91         /* 
  92          * only process if socket is not in use
  93          */
  94 
  95         cli();
  96         if (sk->inuse || in_bh) 
  97         {
  98                 sk->timer.expires = jiffies+10;
  99                 add_timer(&sk->timer);
 100                 sti();
 101                 return;
 102         }
 103 
 104         sk->inuse = 1;
 105         sti();
 106 
 107         /* Always see if we need to send an ack. */
 108 
 109         if (sk->ack_backlog && !sk->zapped) 
 110         {
 111                 sk->prot->read_wakeup (sk);
 112                 if (! sk->dead)
 113                 sk->data_ready(sk,0);
 114         }
 115 
 116         /* Now we need to figure out why the socket was on the timer. */
 117 
 118         switch (why) 
 119         {
 120                 case TIME_DONE:
 121                         if (! sk->dead || sk->state != TCP_CLOSE) 
 122                         {
 123                                 printk ("non dead socket in time_done\n");
 124                                 release_sock (sk);
 125                                 break;
 126                         }
 127                         destroy_sock (sk);
 128                         break;
 129 
 130                 case TIME_DESTROY:
 131                 /*
 132                  *      We've waited for a while for all the memory associated with
 133                  *      the socket to be freed.
 134                  */
 135                         if(sk->wmem_alloc!=0 || sk->rmem_alloc!=0)
 136                         {
 137                                 sk->wmem_alloc++;       /* So it DOESN'T go away */
 138                                 destroy_sock (sk);
 139                                 sk->wmem_alloc--;       /* Might now have hit 0 - fall through and do it again if so */
 140                                 sk->inuse = 0;  /* This will be ok, the destroy won't totally work */
 141                         }
 142                         if(sk->wmem_alloc==0 && sk->rmem_alloc==0)
 143                                 destroy_sock(sk);       /* Socket gone, DON'T update sk->inuse! */
 144                                 break;
 145                 case TIME_CLOSE:
 146                         /* We've waited long enough, close the socket. */
 147                         sk->state = TCP_CLOSE;
 148                         delete_timer (sk);
 149                         /* Kill the ARP entry in case the hardware has changed. */
 150                         arp_destroy (sk->daddr, 0);
 151                         if (!sk->dead)
 152                                 sk->state_change(sk);
 153                         sk->shutdown = SHUTDOWN_MASK;
 154                         reset_timer (sk, TIME_DESTROY, TCP_DONE_TIME);
 155                         release_sock (sk);
 156                         break;
 157                 default:
 158                         printk ("net_timer: timer expired - reason %d is unknown\n", why);
 159                         release_sock (sk);
 160                         break;
 161         }
 162 }
 163
/* */
root/net/ipv4/timer.c

DEFINITIONS
