1 /* 2 * cachedb/cachedb.h - cache from a database external to the program module 3 * 4 * Copyright (c) 2016, 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 a module that uses an external database to cache 40 * dns responses. 41 */ 42 #include "util/module.h" 43 struct cachedb_backend; 44 45 /** 46 * The global variable environment contents for the cachedb 47 * Shared between threads, this represents long term information. 48 * Like database connections. 49 */ 50 struct cachedb_env { 51 /** true is cachedb is enabled, the backend is turned on */ 52 int enabled; 53 54 /** the backend routines */ 55 struct cachedb_backend* backend; 56 57 /** backend specific data here */ 58 void* backend_data; 59 }; 60 61 /** 62 * Per query state for the cachedb module. 63 */ 64 struct cachedb_qstate { 65 int todo; 66 }; 67 68 /** 69 * Backend call routines 70 */ 71 struct cachedb_backend { 72 /** backend name */ 73 const char* name; 74 75 /** Init(env, cachedb_env): false on setup failure */ 76 int (*init)(struct module_env*, struct cachedb_env*); 77 78 /** Deinit - close db for program exit */ 79 void (*deinit)(struct module_env*, struct cachedb_env*); 80 81 /** Lookup (env, cachedb_env, key, result_buffer): true if found */ 82 int (*lookup)(struct module_env*, struct cachedb_env*, char*, 83 struct sldns_buffer*); 84 85 /** Store (env, cachedb_env, key, data, data_len) */ 86 void (*store)(struct module_env*, struct cachedb_env*, char*, 87 uint8_t*, size_t); 88 }; 89 90 #define CACHEDB_HASHSIZE 256 /* bit hash */ 91 92 /** Init the cachedb module */ 93 int cachedb_init(struct module_env* env, int id); 94 /** Deinit the cachedb module */ 95 void cachedb_deinit(struct module_env* env, int id); 96 /** Operate on an event on a query (in qstate). */ 97 void cachedb_operate(struct module_qstate* qstate, enum module_ev event, 98 int id, struct outbound_entry* outbound); 99 /** Subordinate query done, inform this super request of its conclusion */ 100 void cachedb_inform_super(struct module_qstate* qstate, int id, 101 struct module_qstate* super); 102 /** clear the cachedb query-specific contents out of qstate */ 103 void cachedb_clear(struct module_qstate* qstate, int id); 104 /** return memory estimate for cachedb module */ 105 size_t cachedb_get_mem(struct module_env* env, int id); 106 107 /** 108 * Get the function block with pointers to the cachedb functions 109 * @return the function block for "cachedb". 110 */ 111 struct module_func_block* cachedb_get_funcblock(void); 112 113