2 * edns-subnet/addrtree.h -- radix tree for edns subnet cache.
4 * Copyright (c) 2013, NLnet Labs. All rights reserved.
6 * This software is open source.
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9 * modification, are permitted provided that the following conditions
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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
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.)
49 * node.sourcemask==sourcemask && node.elem!=NULL
50 * (This is the most specific question the client can ask.)
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.
61 typedef uint8_t addrlen_t;
62 typedef uint8_t addrkey_t;
66 struct addrnode *root;
67 /** Number of elements in the tree (not always equal to number of
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 */
75 /** Maximum prefix length we are willing to cache. */
77 /** External function to delete elem. Called as
78 * delfunc(addrnode->elem, addrtree->env) */
79 void (*delfunc)(void *, void *);
80 /** Environment for delfunc */
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;
92 /** Payload of node, may be NULL */
94 /** Abs time in seconds in which elem is meaningful */
96 /** Number of significant bits in address. */
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;
109 /** address of connected node */
111 /** length in bits of str */
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 */
122 * Size of tree in bytes.
124 * @return size of tree in bytes.
126 size_t addrtree_size(const struct addrtree *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.
136 * @return new addrtree or NULL on failure.
139 addrtree_create(addrlen_t max_depth, void (*delfunc)(void *, void *),
140 size_t (*sizefunc)(void *), void *env, unsigned int max_node_count);
143 * Free tree and all nodes below.
144 * @param tree: Tree to be freed.
146 void addrtree_delete(struct addrtree *tree);
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
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.
162 void addrtree_insert(struct addrtree *tree, const addrkey_t *addr,
163 addrlen_t sourcemask, addrlen_t scope, void *elem, time_t ttl,
167 * Find a node containing an element in the tree.
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.
175 struct addrnode * addrtree_find(struct addrtree *tree,
176 const addrkey_t *addr, addrlen_t sourcemask, time_t now);
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 */