usr.sbin/mrouted/callout.c

   1 /*      $NetBSD: callout.c,v 1.2 2002/12/06 16:02:55 thorpej Exp $      */
   2
   3 /*
   4  * The mrouted program is covered by the license in the accompanying file
   5  * named "LICENSE".  Use of the mrouted program represents acceptance of
   6  * the terms and conditions listed in that file.
   7  *
   8  * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
   9  * Leland Stanford Junior University.
  10  */
  11
  12 #include "defs.h"
  13
  14 /* the code below implements a callout queue */
  15 static int id = 0;
  16 static struct timeout_q  *Q = 0; /* pointer to the beginning of timeout queue */
  17
  18 static int in_callout = 0;
  19
  20 struct timeout_q {
  21         struct timeout_q *next;         /* next event */
  22         int              id;
  23         cfunc_t          func;          /* function to call */
  24         char             *data;         /* func's data */
  25         int              time;          /* time offset to next event*/
  26 };
  27
  28 #ifdef IGMP_DEBUG
  29 static void print_Q(void);
  30 #else
  31 #define print_Q()
  32 #endif
  33
  34 int secs_remaining(int);
  35
  36 void
  37 callout_init(void)
  38 {
  39     Q = (struct timeout_q *) 0;
  40 }
  41
  42
  43 /*
  44  * signal handler for SIGALARM that is called once every second
  45  */
  46 void
  47 age_callout_queue(void)
  48 {
  49     struct timeout_q *ptr;
  50
  51     if (in_callout)
  52         return;
  53
  54     in_callout = 1;
  55     ptr = Q;
  56
  57     while (ptr) {
  58         if (!ptr->time) {
  59             /* timeout has happened */
  60             Q = Q->next;
  61
  62             in_callout = 0;
  63             if (ptr->func)
  64                 ptr->func(ptr->data);
  65             in_callout = 1;
  66
  67             free(ptr);
  68             ptr = Q;
  69         }
  70         else {
  71             ptr->time --;
  72 #ifdef IGMP_DEBUG
  73             logit(LOG_DEBUG,0,"[callout, age_callout_queue] -- time (%d)", ptr->time);
  74 #endif /* IGMP_DEBUG */
  75             in_callout = 0; return;
  76         }
  77     }
  78     in_callout = 0;
  79     return;
  80 }
  81
  82
  83 /*
  84  * sets the timer
  85  *
  86  * delay: number of units for timeout
  87  * action: function to be called on timeout
  88  * data: what to call the timeout function with
  89  */
  90 int
  91 timer_setTimer(int delay, cfunc_t action, char *data)
  92 {
  93     struct     timeout_q  *ptr, *node, *prev;
  94
  95     if (in_callout)
  96         return -1;
  97
  98     in_callout = 1;
  99
 100     /* create a node */
 101     node = (struct timeout_q *)malloc(sizeof(struct timeout_q));
 102     if (node == 0) {
 103         logit(LOG_WARNING, 0, "Malloc Failed in timer_settimer\n");
 104         in_callout = 0;
 105         return -1;
 106     }
 107     node->func = action;
 108     node->data = data;
 109     node->time = delay;
 110     node->next = 0;
 111     node->id   = ++id;
 112
 113     prev = ptr = Q;
 114
 115     /* insert node in the queue */
 116
 117     /* if the queue is empty, insert the node and return */
 118     if (!Q)
 119         Q = node;
 120     else {
 121         /* chase the pointer looking for the right place */
 122         while (ptr) {
 123
 124             if (delay < ptr->time) {
 125                 /* right place */
 126
 127                 node->next = ptr;
 128                 if (ptr == Q)
 129                     Q = node;
 130                 else
 131                     prev->next = node;
 132                 ptr->time -= node->time;
 133                 print_Q();
 134                 in_callout = 0;
 135                 return node->id;
 136             } else  {
 137                 /* keep moving */
 138
 139                 delay -= ptr->time; node->time = delay;
 140                 prev = ptr;
 141                 ptr = ptr->next;
 142             }
 143         }
 144         prev->next = node;
 145     }
 146     print_Q();
 147     in_callout = 0;
 148     return node->id;
 149 }
 150
 151
 152 /* clears the associated timer */
 153 void
 154 timer_clearTimer(int timer_id)
 155 {
 156     struct timeout_q  *ptr, *prev;
 157
 158     if (in_callout)
 159         return;
 160     if (!timer_id)
 161         return;
 162
 163     in_callout = 1;
 164
 165     prev = ptr = Q;
 166
 167     /*
 168      * find the right node, delete it. the subsequent node's time
 169      * gets bumped up
 170      */
 171
 172     print_Q();
 173     while (ptr) {
 174         if (ptr->id == timer_id) {
 175             /* got the right node */
 176
 177             /* unlink it from the queue */
 178             if (ptr == Q)
 179                 Q = Q->next;
 180             else
 181                 prev->next = ptr->next;
 182
 183             /* increment next node if any */
 184             if (ptr->next != 0)
 185                 (ptr->next)->time += ptr->time;
 186
 187             free(ptr->data);
 188             free(ptr);
 189             print_Q();
 190             in_callout = 0;
 191             return;
 192         }
 193         prev = ptr;
 194         ptr = ptr->next;
 195     }
 196     print_Q();
 197     in_callout = 0;
 198 }
 199
 200 #ifdef IGMP_DEBUG
 201 /*
 202  * debugging utility
 203  */
 204 static void
 205 print_Q(void)
 206 {
 207     struct timeout_q  *ptr;
 208
 209     for(ptr = Q; ptr; ptr = ptr->next)
 210         logit(LOG_DEBUG,0,"(%d,%d) ", ptr->id, ptr->time);
 211 }
 212 #endif /* IGMP_DEBUG */
 213
 214 int
 215 secs_remaining(int timer_id)
 216 {
 217     struct timeout_q  *ptr;
 218     int left=0;
 219
 220     for (ptr = Q; ptr && ptr->id != timer_id; ptr = ptr->next)
 221        left += ptr->time;
 222
 223     if (!ptr) /* not found */
 224        return 0;
 225
 226     return left + ptr->time;
 227 }