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      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 responsibility 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 */
    106