usr.sbin/mrouted/callout.c

   1 /*
   2  * The mrouted program is covered by the license in the accompanying file
   3  * named "LICENSE".  Use of the mrouted program represents acceptance of
   4  * the terms and conditions listed in that file.
   5  *
   6  * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
   7  * Leland Stanford Junior University.
   8  *
   9  *
  10  * callout.c,v 3.8.4.8 1998/01/06 01:58:45 fenner Exp
  11  *
  12  * $FreeBSD: src/usr.sbin/mrouted/callout.c,v 1.12 1999/08/28 01:17:03 peter Exp $
  13  * $DragonFly: src/usr.sbin/mrouted/callout.c,v 1.6 2008/04/20 19:26:53 swildner Exp $
  14  */
  15
  16 #include "defs.h"
  17
  18 /* the code below implements a callout queue */
  19 static int id = 0;
  20 static struct timeout_q  *Q = 0; /* pointer to the beginning of timeout queue */
  21
  22 struct timeout_q {
  23         struct timeout_q *next;         /* next event */
  24         int              id;
  25         cfunc_t          func;          /* function to call */
  26         void             *data;         /* func's data */
  27         int              time;          /* time offset to next event*/
  28 };
  29
  30 #ifdef IGMP_DEBUG
  31 static void print_Q(void);
  32 #else
  33 #define print_Q()
  34 #endif
  35
  36 void
  37 callout_init(void)
  38 {
  39     Q = (struct timeout_q *) 0;
  40 }
  41
  42 void
  43 free_all_callouts(void)
  44 {
  45     struct timeout_q *p;
  46
  47     while (Q) {
  48         p = Q;
  49         Q = Q->next;
  50         free(p);
  51     }
  52 }
  53
  54
  55 /*
  56  * elapsed_time seconds have passed; perform all the events that should
  57  * happen.
  58  */
  59 void
  60 age_callout_queue(int elapsed_time)
  61 {
  62     struct timeout_q *ptr;
  63     int i = 0;
  64
  65     for (ptr = Q; ptr; ptr = Q, i++) {
  66         if (ptr->time > elapsed_time) {
  67             ptr->time -= elapsed_time;
  68             return;
  69         } else {
  70             elapsed_time -= ptr->time;
  71             Q = Q->next;
  72             IF_DEBUG(DEBUG_TIMEOUT)
  73             log(LOG_DEBUG, 0, "about to call timeout %d (#%d)", ptr->id, i);
  74             if (ptr->func)
  75                 ptr->func(ptr->data);
  76             free(ptr);
  77         }
  78     }
  79 }
  80
  81 /*
  82  * Return in how many seconds age_callout_queue() would like to be called.
  83  * Return -1 if there are no events pending.
  84  */
  85 int
  86 timer_nextTimer(void)
  87 {
  88     if (Q) {
  89         if (Q->time < 0) {
  90             log(LOG_WARNING, 0, "timer_nextTimer top of queue says %d",
  91                         Q->time);
  92             return 0;
  93         }
  94         return Q->time;
  95     }
  96     return -1;
  97 }
  98
  99 /*
 100  * sets the timer
 101  *
 102  * delay  - number of units for timeout
 103  * action - function to be called on timeout
 104  * data   - what to call the timeout function with
 105  */
 106 int
 107 timer_setTimer(int delay, cfunc_t action, void *data)
 108 {
 109     struct     timeout_q  *ptr, *node, *prev;
 110     int i = 0;
 111
 112     /* create a node */
 113     node = (struct timeout_q *)malloc(sizeof(struct timeout_q));
 114     if (node == 0) {
 115         log(LOG_WARNING, 0, "Malloc Failed in timer_setTimer\n");
 116         return -1;
 117     }
 118     node->func = action;
 119     node->data = data;
 120     node->time = delay;
 121     node->next = 0;
 122     node->id   = ++id;
 123
 124     prev = ptr = Q;
 125
 126     /* insert node in the queue */
 127
 128     /* if the queue is empty, insert the node and return */
 129     if (!Q)
 130         Q = node;
 131     else {
 132         /* chase the pointer looking for the right place */
 133         while (ptr) {
 134
 135             if (delay < ptr->time) {
 136                 /* right place */
 137
 138                 node->next = ptr;
 139                 if (ptr == Q)
 140                     Q = node;
 141                 else
 142                     prev->next = node;
 143                 ptr->time -= node->time;
 144                 print_Q();
 145                 IF_DEBUG(DEBUG_TIMEOUT)
 146                 log(LOG_DEBUG, 0, "created timeout %d (#%d)", node->id, i);
 147                 return node->id;
 148             } else  {
 149                 /* keep moving */
 150
 151                 delay -= ptr->time; node->time = delay;
 152                 prev = ptr;
 153                 ptr = ptr->next;
 154             }
 155             i++;
 156         }
 157         prev->next = node;
 158     }
 159     print_Q();
 160     IF_DEBUG(DEBUG_TIMEOUT)
 161     log(LOG_DEBUG, 0, "created timeout %d (#%d)", node->id, i);
 162     return node->id;
 163 }
 164
 165 /* returns the time until the timer is scheduled */
 166 int
 167 timer_leftTimer(int timer_id)
 168 {
 169     struct timeout_q *ptr;
 170     int left = 0;
 171
 172     if (!timer_id)
 173         return -1;
 174
 175     for (ptr = Q; ptr; ptr = ptr->next) {
 176         left += ptr->time;
 177         if (ptr->id == timer_id)
 178             return left;
 179     }
 180     return -1;
 181 }
 182
 183 /* clears the associated timer.  Returns 1 if succeeded. */
 184 int
 185 timer_clearTimer(int timer_id)
 186 {
 187     struct timeout_q  *ptr, *prev;
 188     int i = 0;
 189
 190     if (!timer_id)
 191         return 0;
 192
 193     prev = ptr = Q;
 194
 195     /*
 196      * find the right node, delete it. the subsequent node's time
 197      * gets bumped up
 198      */
 199
 200     print_Q();
 201     while (ptr) {
 202         if (ptr->id == timer_id) {
 203             /* got the right node */
 204
 205             /* unlink it from the queue */
 206             if (ptr == Q)
 207                 Q = Q->next;
 208             else
 209                 prev->next = ptr->next;
 210
 211             /* increment next node if any */
 212             if (ptr->next != 0)
 213                 (ptr->next)->time += ptr->time;
 214
 215             if (ptr->data)
 216                 free(ptr->data);
 217             IF_DEBUG(DEBUG_TIMEOUT)
 218             log(LOG_DEBUG, 0, "deleted timer %d (#%d)", ptr->id, i);
 219             free(ptr);
 220             print_Q();
 221             return 1;
 222         }
 223         prev = ptr;
 224         ptr = ptr->next;
 225         i++;
 226     }
 227     IF_DEBUG(DEBUG_TIMEOUT)
 228     log(LOG_DEBUG, 0, "failed to delete timer %d (#%d)", timer_id, i);
 229     print_Q();
 230     return 0;
 231 }
 232
 233 #ifdef IGMP_DEBUG
 234 /*
 235  * debugging utility
 236  */
 237 static void
 238 print_Q(void)
 239 {
 240     struct timeout_q  *ptr;
 241
 242     IF_DEBUG(DEBUG_TIMEOUT)
 243         for (ptr = Q; ptr; ptr = ptr->next)
 244             log(LOG_DEBUG, 0, "(%d,%d) ", ptr->id, ptr->time);
 245 }
 246 #endif /* IGMP_DEBUG */