2 * services/cache/dns.h - Cache services for DNS using msg and rrset caches.
4 * Copyright (c) 2007, NLnet Labs. All rights reserved.
6 * This software is open source.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
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.
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.
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.
39 * This file contains the DNS cache.
42 #ifndef SERVICES_CACHE_DNS_H
43 #define SERVICES_CACHE_DNS_H
44 #include "util/storage/lruhash.h"
45 #include "util/data/msgreply.h"
53 * Region allocated message reply
57 struct query_info qinfo;
58 /** reply info - ptr to packed repinfo structure */
59 struct reply_info *rep;
63 * Allocate a dns_msg with malloc/alloc structure and store in dns cache.
65 * @param env: environment, with alloc structure and dns cache.
66 * @param qinf: query info, the query for which answer is stored.
67 * this is allocated in a region, and will be copied to malloc area
69 * @param rep: reply in dns_msg from dns_alloc_msg for example.
70 * this is allocated in a region, and will be copied to malloc area
72 * @param is_referral: If true, then the given message to be stored is a
73 * referral. The cache implementation may use this as a hint.
74 * It will store only the RRsets, not the message.
75 * @param leeway: TTL value, if not 0, other rrsets are considered expired
76 * that many seconds before actual TTL expiry.
77 * @param pside: if true, information came from a server which was fetched
78 * from the parentside of the zonecut. This means that the type NS
79 * can be updated to full TTL even in prefetch situations.
80 * @param region: region to allocate better entries from cache into.
81 * (used when is_referral is false).
82 * @param flags: flags with BIT_CD for AAAA queries in dns64 translation.
83 * @return 0 on alloc error (out of memory).
85 int dns_cache_store(struct module_env* env, struct query_info* qinf,
86 struct reply_info* rep, int is_referral, time_t leeway, int pside,
87 struct regional* region, uint16_t flags);
90 * Store message in the cache. Stores in message cache and rrset cache.
91 * Both qinfo and rep should be malloced and are put in the cache.
92 * They should not be used after this call, as they are then in shared cache.
93 * Does not return errors, they are logged and only lead to less cache.
95 * @param env: module environment with the DNS cache.
96 * @param qinfo: query info
97 * @param hash: hash over qinfo.
98 * @param rep: reply info, together with qinfo makes up the message.
99 * Adjusts the reply info TTLs to absolute time.
100 * @param leeway: TTL value, if not 0, other rrsets are considered expired
101 * that many seconds before actual TTL expiry.
102 * @param pside: if true, information came from a server which was fetched
103 * from the parentside of the zonecut. This means that the type NS
104 * can be updated to full TTL even in prefetch situations.
105 * @param qrep: message that can be altered with better rrs from cache.
106 * @param region: to allocate into for qmsg.
108 void dns_cache_store_msg(struct module_env* env, struct query_info* qinfo,
109 hashvalue_type hash, struct reply_info* rep, time_t leeway, int pside,
110 struct reply_info* qrep, struct regional* region);
113 * Find a delegation from the cache.
114 * @param env: module environment with the DNS cache.
115 * @param qname: query name.
116 * @param qnamelen: length of qname.
117 * @param qtype: query type.
118 * @param qclass: query class.
119 * @param region: where to allocate result delegation.
120 * @param msg: if not NULL, delegation message is returned here, synthesized
122 * @param timenow: the time now, for checking if TTL on cache entries is OK.
123 * @return new delegation or NULL on error or if not found in cache.
125 struct delegpt* dns_cache_find_delegation(struct module_env* env,
126 uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
127 struct regional* region, struct dns_msg** msg, time_t timenow);
130 * generate dns_msg from cached message
131 * @param env: module environment with the DNS cache. NULL if the LRU from cache
132 * does not need to be touched.
133 * @param q: query info, contains qname that will make up the dns message.
134 * @param r: reply info that, together with qname, will make up the dns message.
135 * @param region: where to allocate dns message.
136 * @param now: the time now, for check if TTL on cache entry is ok.
137 * @param scratch: where to allocate temporary data.
139 struct dns_msg* tomsg(struct module_env* env, struct query_info* q,
140 struct reply_info* r, struct regional* region, time_t now,
141 struct regional* scratch);
144 * Find cached message
145 * @param env: module environment with the DNS cache.
146 * @param qname: query name.
147 * @param qnamelen: length of qname.
148 * @param qtype: query type.
149 * @param qclass: query class.
150 * @param flags: flags with BIT_CD for AAAA queries in dns64 translation.
151 * @param region: where to allocate result.
152 * @param scratch: where to allocate temporary data.
153 * @return new response message (alloced in region, rrsets do not have IDs).
154 * or NULL on error or if not found in cache.
155 * TTLs are made relative to the current time.
157 struct dns_msg* dns_cache_lookup(struct module_env* env,
158 uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
159 uint16_t flags, struct regional* region, struct regional* scratch);
162 * find and add A and AAAA records for missing nameservers in delegpt
163 * @param env: module environment with rrset cache
164 * @param qclass: which class to look in.
165 * @param region: where to store new dp info.
166 * @param dp: delegation point to fill missing entries.
167 * @return false on alloc failure.
169 int cache_fill_missing(struct module_env* env, uint16_t qclass,
170 struct regional* region, struct delegpt* dp);
173 * Utility, create new, unpacked data structure for cache response.
174 * QR bit set, no AA. Query set as indicated. Space for number of rrsets.
175 * @param qname: query section name
176 * @param qnamelen: len of qname
177 * @param qtype: query section type
178 * @param qclass: query section class
179 * @param region: where to alloc.
180 * @param capacity: number of rrsets space to create in the array.
181 * @return new dns_msg struct or NULL on mem fail.
183 struct dns_msg* dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype,
184 uint16_t qclass, struct regional* region, size_t capacity);
187 * Add rrset to authority section in unpacked dns_msg message. Must have enough
188 * space left, does not grow the array.
189 * @param msg: msg to put it in.
190 * @param region: region to alloc in
191 * @param rrset: to add in authority section
193 * @return true if worked, false on fail
195 int dns_msg_authadd(struct dns_msg* msg, struct regional* region,
196 struct ub_packed_rrset_key* rrset, time_t now);
199 * Adjust the prefetch_ttl for a cached message. This adds a value to the
200 * prefetch ttl - postponing the time when it will be prefetched for future
202 * @param env: module environment with caches and time.
203 * @param qinfo: query info for the query that needs adjustment.
204 * @param adjust: time in seconds to add to the prefetch_leeway.
205 * @param flags: flags with BIT_CD for AAAA queries in dns64 translation.
206 * @return false if not in cache. true if added.
208 int dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo,
209 time_t adjust, uint16_t flags);
211 /** lookup message in message cache
212 * the returned nonNULL entry is locked and has to be unlocked by the caller */
213 struct msgreply_entry* msg_cache_lookup(struct module_env* env,
214 uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
215 uint16_t flags, time_t now, int wr);
217 #endif /* SERVICES_CACHE_DNS_H */