1 /* 2 * iterator/iter_fwd.h - iterative resolver module forward zones. 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 assist the iterator module. 40 * Keep track of forward zones, and read those from config. 41 */ 42 43 #ifndef ITERATOR_ITER_FWD_H 44 #define ITERATOR_ITER_FWD_H 45 #include "util/rbtree.h" 46 struct config_file; 47 struct delegpt; 48 49 /** 50 * Iterator forward zones structure 51 */ 52 struct iter_forwards { 53 /** 54 * Zones are stored in this tree. Sort order is specially chosen. 55 * first sorted on qclass. Then on dname in nsec-like order, so that 56 * a lookup on class, name will return an exact match or the closest 57 * match which gives the ancestor needed. 58 * contents of type iter_forward_zone. 59 */ 60 rbtree_type* tree; 61 }; 62 63 /** 64 * Iterator forward servers for a particular zone. 65 */ 66 struct iter_forward_zone { 67 /** redblacktree node, key is this structure: class and name */ 68 rbnode_type node; 69 /** name */ 70 uint8_t* name; 71 /** length of name */ 72 size_t namelen; 73 /** number of labels in name */ 74 int namelabs; 75 /** delegation point with forward server information for this zone. 76 * If NULL then this forward entry is used to indicate that a 77 * stub-zone with the same name exists, and should be used. 78 * This delegation point is malloced. 79 */ 80 struct delegpt* dp; 81 /** pointer to parent in tree (or NULL if none) */ 82 struct iter_forward_zone* parent; 83 /** class. host order. */ 84 uint16_t dclass; 85 }; 86 87 /** 88 * Create forwards 89 * @return new forwards or NULL on error. 90 */ 91 struct iter_forwards* forwards_create(void); 92 93 /** 94 * Delete forwards. 95 * @param fwd: to delete. 96 */ 97 void forwards_delete(struct iter_forwards* fwd); 98 99 /** 100 * Process forwards config. 101 * @param fwd: where to store. 102 * @param cfg: config options. 103 * @return 0 on error. 104 */ 105 int forwards_apply_cfg(struct iter_forwards* fwd, struct config_file* cfg); 106 107 /** 108 * Find forward zone exactly by name 109 * @param fwd: forward storage. 110 * @param qname: The qname of the query. 111 * @param qclass: The qclass of the query. 112 * @return: A delegation point or null. 113 */ 114 struct delegpt* forwards_find(struct iter_forwards* fwd, uint8_t* qname, 115 uint16_t qclass); 116 117 /** 118 * Find forward zone information 119 * For this qname/qclass find forward zone information, returns delegation 120 * point with server names and addresses, or NULL if no forwarding is needed. 121 * 122 * @param fwd: forward storage. 123 * @param qname: The qname of the query. 124 * @param qclass: The qclass of the query. 125 * @return: A delegation point if the query has to be forwarded to that list, 126 * otherwise null. 127 */ 128 struct delegpt* forwards_lookup(struct iter_forwards* fwd, 129 uint8_t* qname, uint16_t qclass); 130 131 /** 132 * Same as forwards_lookup, but for the root only 133 * @param fwd: forward storage. 134 * @param qclass: The qclass of the query. 135 * @return: A delegation point if root forward exists, otherwise null. 136 */ 137 struct delegpt* forwards_lookup_root(struct iter_forwards* fwd, 138 uint16_t qclass); 139 140 /** 141 * Find next root item in forwards lookup tree. 142 * @param fwd: the forward storage 143 * @param qclass: class to look at next, or higher. 144 * @return false if none found, or if true stored in qclass. 145 */ 146 int forwards_next_root(struct iter_forwards* fwd, uint16_t* qclass); 147 148 /** 149 * Get memory in use by forward storage 150 * @param fwd: forward storage. 151 * @return bytes in use 152 */ 153 size_t forwards_get_mem(struct iter_forwards* fwd); 154 155 /** compare two fwd entries */ 156 int fwd_cmp(const void* k1, const void* k2); 157 158 /** 159 * Add zone to forward structure. For external use since it recalcs 160 * the tree parents. 161 * @param fwd: the forward data structure 162 * @param c: class of zone 163 * @param dp: delegation point with name and target nameservers for new 164 * forward zone. malloced. 165 * @return false on failure (out of memory); 166 */ 167 int forwards_add_zone(struct iter_forwards* fwd, uint16_t c, 168 struct delegpt* dp); 169 170 /** 171 * Remove zone from forward structure. For external use since it 172 * recalcs the tree parents. 173 * @param fwd: the forward data structure 174 * @param c: class of zone 175 * @param nm: name of zone (in uncompressed wireformat). 176 */ 177 void forwards_delete_zone(struct iter_forwards* fwd, uint16_t c, uint8_t* nm); 178 179 /** 180 * Add stub hole (empty entry in forward table, that makes resolution skip 181 * a forward-zone because the stub zone should override the forward zone). 182 * Does not add one if not necessary. 183 * @param fwd: the forward data structure 184 * @param c: class of zone 185 * @param nm: name of zone (in uncompressed wireformat). 186 * @return false on failure (out of memory); 187 */ 188 int forwards_add_stub_hole(struct iter_forwards* fwd, uint16_t c, uint8_t* nm); 189 190 /** 191 * Remove stub hole, if one exists. 192 * @param fwd: the forward data structure 193 * @param c: class of zone 194 * @param nm: name of zone (in uncompressed wireformat). 195 */ 196 void forwards_delete_stub_hole(struct iter_forwards* fwd, uint16_t c, 197 uint8_t* nm); 198 199 #endif /* ITERATOR_ITER_FWD_H */ 200