unbound/services/outbound_list.h

   1 /*
   2  * services/outbound_list.h - keep list of outbound serviced queries.
   3  *
   4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  15  * Redistributions in binary form must reproduce the above copyright notice,
  16  * this list of conditions and the following disclaimer in the documentation
  17  * and/or other materials provided with the distribution.
  18  *
  19  * Neither the name of the NLNET LABS nor the names of its contributors may
  20  * be used to endorse or promote products derived from this software without
  21  * specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains functions to help a module keep track of the
  40  * queries it has outstanding to authoritative servers.
  41  */
  42 #ifndef SERVICES_OUTBOUND_LIST_H
  43 #define SERVICES_OUTBOUND_LIST_H
  44 struct outbound_entry;
  45 struct serviced_query;
  46 struct module_qstate;
  47
  48 /**
  49  * The outbound list. This structure is part of the module specific query
  50  * state.
  51  */
  52 struct outbound_list {
  53         /** The linked list of outbound query entries. */
  54         struct outbound_entry* first;
  55 };
  56
  57 /**
  58  * Outbound list entry. A serviced query sent by a module processing the
  59  * query from the qstate. Double linked list to aid removal.
  60  */
  61 struct outbound_entry {
  62         /** next in list */
  63         struct outbound_entry* next;
  64         /** prev in list */
  65         struct outbound_entry* prev;
  66         /** The query that was sent out */
  67         struct serviced_query* qsent;
  68         /** the module query state that sent it */
  69         struct module_qstate* qstate;
  70 };
  71
  72 /**
  73  * Init the user allocated outbound list structure
  74  * @param list: the list structure.
  75  */
  76 void outbound_list_init(struct outbound_list* list);
  77
  78 /**
  79  * Clear the user owner outbound list structure.
  80  * Deletes serviced queries.
  81  * @param list: the list structure. It is cleared, but the list struct itself
  82  *      is callers responsability to delete.
  83  */
  84 void outbound_list_clear(struct outbound_list* list);
  85
  86 /**
  87  * Insert new entry into the list. Caller must allocate the entry with malloc.
  88  * qstate and qsent are set by caller.
  89  * @param list: the list to add to.
  90  * @param e: entry to add, it is only half initialised at call start, fully
  91  *      initialised at call end.
  92  */
  93 void outbound_list_insert(struct outbound_list* list,
  94         struct outbound_entry* e);
  95
  96 /**
  97  * Remove an entry from the list, and deletes it.
  98  * Deletes serviced query in the entry.
  99  * @param list: the list to remove from.
 100  * @param e: the entry to remove.
 101  */
 102 void outbound_list_remove(struct outbound_list* list,
 103         struct outbound_entry* e);
 104
 105 #endif /* SERVICES_OUTBOUND_LIST_H */