programs/charon/charon/queues/send_queue.c

   1 /**
   2  * @file send_queue.c
   3  *
   4  * @brief Implementation of send_queue_t.
   5  *
   6  */
   7
   8 /*
   9  * Copyright (C) 2005 Jan Hutter, Martin Willi
  10  * Hochschule fuer Technik Rapperswil
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License as published by the
  14  * Free Software Foundation; either version 2 of the License, or (at your
  15  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  */
  22
  23 #include <pthread.h>
  24
  25 #include "send_queue.h"
  26
  27 #include <utils/linked_list.h>
  28
  29
  30 typedef struct private_send_queue_t private_send_queue_t;
  31
  32 /**
  33  * @brief Private Variables and Functions of send_queue class
  34  *
  35  */
  36 struct private_send_queue_t {
  37         /**
  38          * Public part of the send_queue_t object
  39          */
  40         send_queue_t public;
  41
  42         /**
  43          * The packets are stored in a linked list
  44          */
  45         linked_list_t *list;
  46
  47         /**
  48          * access to linked_list is locked through this mutex
  49          */
  50         pthread_mutex_t mutex;
  51
  52         /**
  53          * If the queue is empty a thread has to wait
  54          * This condvar is used to wake up such a thread
  55          */
  56         pthread_cond_t condvar;
  57 };
  58
  59
  60 /**
  61  * implements send_queue_t.get_count
  62  */
  63 static int get_count(private_send_queue_t *this)
  64 {
  65         int count;
  66         pthread_mutex_lock(&(this->mutex));
  67         count = this->list->get_count(this->list);
  68         pthread_mutex_unlock(&(this->mutex));
  69         return count;
  70 }
  71
  72 /**
  73  * implements send_queue_t.get
  74  */
  75 static packet_t *get(private_send_queue_t *this)
  76 {
  77         int oldstate;
  78         packet_t *packet;
  79         pthread_mutex_lock(&(this->mutex));
  80         /* go to wait while no packets available */
  81
  82         while(this->list->get_count(this->list) == 0)
  83         {
  84                 /* add mutex unlock handler for cancellation, enable cancellation */
  85                 pthread_cleanup_push((void(*)(void*))pthread_mutex_unlock, (void*)&(this->mutex));
  86                 pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
  87                 pthread_cond_wait( &(this->condvar), &(this->mutex));
  88
  89                 /* reset cancellation, remove mutex-unlock handler (without executing) */
  90                 pthread_setcancelstate(oldstate, NULL);
  91                 pthread_cleanup_pop(0);
  92         }
  93         this->list->remove_first(this->list,(void **)&packet);
  94         pthread_mutex_unlock(&(this->mutex));
  95         return packet;
  96 }
  97
  98 /**
  99  * implements send_queue_t.add
 100  */
 101 static void add(private_send_queue_t *this, packet_t *packet)
 102 {
 103         pthread_mutex_lock(&(this->mutex));
 104         this->list->insert_last(this->list,packet);
 105         pthread_cond_signal( &(this->condvar));
 106         pthread_mutex_unlock(&(this->mutex));
 107 }
 108
 109 /**
 110  * implements send_queue_t.destroy
 111  */
 112 static void destroy (private_send_queue_t *this)
 113 {
 114
 115         /* destroy all packets in list before destroying list */
 116         while (this->list->get_count(this->list) > 0)
 117         {
 118                 packet_t *packet;
 119                 if (this->list->remove_first(this->list,(void *) &packet) != SUCCESS)
 120                 {
 121                         this->list->destroy(this->list);
 122                         break;
 123                 }
 124                 packet->destroy(packet);
 125         }
 126         this->list->destroy(this->list);
 127
 128         pthread_mutex_destroy(&(this->mutex));
 129
 130         pthread_cond_destroy(&(this->condvar));
 131
 132         free(this);
 133 }
 134
 135 /*
 136  *
 137  * Documented in header
 138  */
 139 send_queue_t *send_queue_create()
 140 {
 141         private_send_queue_t *this = malloc_thing(private_send_queue_t);
 142
 143         this->public.get_count = (int(*)(send_queue_t*)) get_count;
 144         this->public.get = (packet_t*(*)(send_queue_t*)) get;
 145         this->public.add = (void(*)(send_queue_t*, packet_t*)) add;
 146         this->public.destroy = (void(*)(send_queue_t*)) destroy;
 147
 148         this->list = linked_list_create();
 149         pthread_mutex_init(&(this->mutex), NULL);
 150         pthread_cond_init(&(this->condvar), NULL);
 151
 152         return (&this->public);
 153 }