1 /* 2 * edns-subnet/addrtree.h -- radix tree for edns subnet cache. 3 * 4 * Copyright (c) 2013, 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 * The addrtree is a radix tree designed for edns subnet. Most notable 39 * is the addition of 'scope' to a node. Scope is only relevant for 40 * nodes with elem set, it indicates the number of bits the authority 41 * desires. 42 * 43 * For retrieving data one needs an address and address length 44 * (sourcemask). While traversing the tree the first matching node is 45 * returned. A node matches when 46 * node.scope<=sourcemask && node.elem!=NULL 47 * (This is the most specific answer the authority has.) 48 * or 49 * node.sourcemask==sourcemask && node.elem!=NULL 50 * (This is the most specific question the client can ask.) 51 * 52 * Insertion needs an address, sourcemask and scope. The length of the 53 * address is capped by min(sourcemask, scope). While traversing the 54 * tree the scope of all visited nodes is updated. This ensures we are 55 * always able to find the most specific answer available. 56 */ 57 58 #ifndef ADDRTREE_H 59 #define ADDRTREE_H 60 61 typedef uint8_t addrlen_t; 62 typedef uint8_t addrkey_t; 63 #define KEYWIDTH 8 64 65 struct addrtree { 66 struct addrnode *root; 67 /** Number of elements in the tree (not always equal to number of 68 * nodes) */ 69 unsigned int node_count; 70 /** Maximum number of allowed nodes, will be enforced by LRU list. 71 * Excluding the root node, 0 for unlimited */ 72 unsigned int max_node_count; 73 /** Size of tree in bytes */ 74 size_t size_bytes; 75 /** Maximum prefix length we are willing to cache. */ 76 addrlen_t max_depth; 77 /** External function to delete elem. Called as 78 * delfunc(addrnode->elem, addrtree->env) */ 79 void (*delfunc)(void *, void *); 80 /** Environment for delfunc */ 81 void *env; 82 /** External function returning size of elem. Called as 83 * sizefunc(addrnode->elem) */ 84 size_t (*sizefunc)(void *); 85 /** first node in LRU list, first candidate to go */ 86 struct addrnode* first; 87 /** last node in LRU list, last candidate to go */ 88 struct addrnode *last; 89 }; 90 91 struct addrnode { 92 /** Payload of node, may be NULL */ 93 void *elem; 94 /** Abs time in seconds in which elem is meaningful */ 95 time_t ttl; 96 /** Number of significant bits in address. */ 97 addrlen_t scope; 98 /** A node can have 0-2 edges, set to NULL for unused */ 99 struct addredge *edge[2]; 100 /** edge between this node and parent */ 101 struct addredge *parent_edge; 102 /** previous node in LRU list */ 103 struct addrnode *prev; 104 /** next node in LRU list */ 105 struct addrnode *next; 106 }; 107 108 struct addredge { 109 /** address of connected node */ 110 addrkey_t *str; 111 /** length in bits of str */ 112 addrlen_t len; 113 /** child node this edge is connected to */ 114 struct addrnode *node; 115 /** Parent node this ege is connected to */ 116 struct addrnode *parent_node; 117 /** Index of this edge in parent_node */ 118 int parent_index; 119 }; 120 121 /** 122 * Size of tree in bytes. 123 * @param tree: Tree. 124 * @return size of tree in bytes. 125 */ 126 size_t addrtree_size(const struct addrtree *tree); 127 128 /** 129 * Create a new tree. 130 * @param max_depth: Tree will cap keys to this length. 131 * @param delfunc: f(element, env) delete element. 132 * @param sizefunc: f(element) returning the size of element. 133 * @param env: Module environment for alloc information. 134 * @param max_node_count: Maximum size of this data structure in nodes. 135 * 0 for unlimited. 136 * @return new addrtree or NULL on failure. 137 */ 138 struct addrtree * 139 addrtree_create(addrlen_t max_depth, void (*delfunc)(void *, void *), 140 size_t (*sizefunc)(void *), void *env, unsigned int max_node_count); 141 142 /** 143 * Free tree and all nodes below. 144 * @param tree: Tree to be freed. 145 */ 146 void addrtree_delete(struct addrtree *tree); 147 148 /** 149 * Insert an element in the tree. Failures are silent. Sourcemask and 150 * scope might be changed according to local policy. Caller should no 151 * longer access elem, it could be free'd now or later during future 152 * inserts. 153 * 154 * @param tree: Tree insert elem in. 155 * @param addr: key for element lookup. 156 * @param sourcemask: Length of addr in bits. 157 * @param scope: Number of significant bits in addr. 158 * @param elem: data to store in the tree. 159 * @param ttl: elem is valid up to this time, seconds. 160 * @param now: Current time in seconds. 161 */ 162 void addrtree_insert(struct addrtree *tree, const addrkey_t *addr, 163 addrlen_t sourcemask, addrlen_t scope, void *elem, time_t ttl, 164 time_t now); 165 166 /** 167 * Find a node containing an element in the tree. 168 * 169 * @param tree: Tree to search. 170 * @param addr: key for element lookup. 171 * @param sourcemask: Length of addr in bits. 172 * @param now: Current time in seconds. 173 * @return addrnode or NULL on miss. 174 */ 175 struct addrnode * addrtree_find(struct addrtree *tree, 176 const addrkey_t *addr, addrlen_t sourcemask, time_t now); 177 178 /** Wrappers for static functions to unit test */ 179 int unittest_wrapper_addrtree_cmpbit(const addrkey_t *key1, 180 const addrkey_t *key2, addrlen_t n); 181 addrlen_t unittest_wrapper_addrtree_bits_common(const addrkey_t *s1, 182 addrlen_t l1, const addrkey_t *s2, addrlen_t l2, addrlen_t skip); 183 int unittest_wrapper_addrtree_getbit(const addrkey_t *addr, 184 addrlen_t addrlen, addrlen_t n); 185 int unittest_wrapper_addrtree_issub(const addrkey_t *s1, addrlen_t l1, 186 const addrkey_t *s2, addrlen_t l2, addrlen_t skip); 187 #endif /* ADDRTREE_H */ 188