1 /* 2 * services/cache/dns.h - Cache services for DNS using msg and rrset caches. 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 LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 27 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains the DNS cache. 40 */ 41 42 #ifndef SERVICES_CACHE_DNS_H 43 #define SERVICES_CACHE_DNS_H 44 #include "util/storage/lruhash.h" 45 #include "util/data/msgreply.h" 46 struct module_env; 47 struct query_info; 48 struct reply_info; 49 struct regional; 50 struct delegpt; 51 52 /** 53 * Region allocated message reply 54 */ 55 struct dns_msg { 56 /** query info */ 57 struct query_info qinfo; 58 /** reply info - ptr to packed repinfo structure */ 59 struct reply_info *rep; 60 }; 61 62 /** 63 * Allocate a dns_msg with malloc/alloc structure and store in dns cache. 64 * 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 68 * before insertion. 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 71 * before insertion. 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 * @return 0 on alloc error (out of memory). 83 */ 84 int dns_cache_store(struct module_env* env, struct query_info* qinf, 85 struct reply_info* rep, int is_referral, uint32_t leeway, int pside, 86 struct regional* region); 87 88 /** 89 * Store message in the cache. Stores in message cache and rrset cache. 90 * Both qinfo and rep should be malloced and are put in the cache. 91 * They should not be used after this call, as they are then in shared cache. 92 * Does not return errors, they are logged and only lead to less cache. 93 * 94 * @param env: module environment with the DNS cache. 95 * @param qinfo: query info 96 * @param hash: hash over qinfo. 97 * @param rep: reply info, together with qinfo makes up the message. 98 * Adjusts the reply info TTLs to absolute time. 99 * @param leeway: TTL value, if not 0, other rrsets are considered expired 100 * that many seconds before actual TTL expiry. 101 * @param pside: if true, information came from a server which was fetched 102 * from the parentside of the zonecut. This means that the type NS 103 * can be updated to full TTL even in prefetch situations. 104 * @param qrep: message that can be altered with better rrs from cache. 105 * @param region: to allocate into for qmsg. 106 */ 107 void dns_cache_store_msg(struct module_env* env, struct query_info* qinfo, 108 hashvalue_t hash, struct reply_info* rep, uint32_t leeway, int pside, 109 struct reply_info* qrep, struct regional* region); 110 111 /** 112 * Find a delegation from the cache. 113 * @param env: module environment with the DNS cache. 114 * @param qname: query name. 115 * @param qnamelen: length of qname. 116 * @param qtype: query type. 117 * @param qclass: query class. 118 * @param region: where to allocate result delegation. 119 * @param msg: if not NULL, delegation message is returned here, synthesized 120 * from the cache. 121 * @param timenow: the time now, for checking if TTL on cache entries is OK. 122 * @return new delegation or NULL on error or if not found in cache. 123 */ 124 struct delegpt* dns_cache_find_delegation(struct module_env* env, 125 uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, 126 struct regional* region, struct dns_msg** msg, uint32_t timenow); 127 128 /** 129 * Find cached message 130 * @param env: module environment with the DNS cache. 131 * @param qname: query name. 132 * @param qnamelen: length of qname. 133 * @param qtype: query type. 134 * @param qclass: query class. 135 * @param region: where to allocate result. 136 * @param scratch: where to allocate temporary data. 137 * @return new response message (alloced in region, rrsets do not have IDs). 138 * or NULL on error or if not found in cache. 139 * TTLs are made relative to the current time. 140 */ 141 struct dns_msg* dns_cache_lookup(struct module_env* env, 142 uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, 143 struct regional* region, struct regional* scratch); 144 145 /** 146 * find and add A and AAAA records for missing nameservers in delegpt 147 * @param env: module environment with rrset cache 148 * @param qclass: which class to look in. 149 * @param region: where to store new dp info. 150 * @param dp: delegation point to fill missing entries. 151 * @return false on alloc failure. 152 */ 153 int cache_fill_missing(struct module_env* env, uint16_t qclass, 154 struct regional* region, struct delegpt* dp); 155 156 /** 157 * Utility, create new, unpacked data structure for cache response. 158 * QR bit set, no AA. Query set as indicated. Space for number of rrsets. 159 * @param qname: query section name 160 * @param qnamelen: len of qname 161 * @param qtype: query section type 162 * @param qclass: query section class 163 * @param region: where to alloc. 164 * @param capacity: number of rrsets space to create in the array. 165 * @return new dns_msg struct or NULL on mem fail. 166 */ 167 struct dns_msg* dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype, 168 uint16_t qclass, struct regional* region, size_t capacity); 169 170 /** 171 * Add rrset to authority section in unpacked dns_msg message. Must have enough 172 * space left, does not grow the array. 173 * @param msg: msg to put it in. 174 * @param region: region to alloc in 175 * @param rrset: to add in authority section 176 * @param now: now. 177 * @return true if worked, false on fail 178 */ 179 int dns_msg_authadd(struct dns_msg* msg, struct regional* region, 180 struct ub_packed_rrset_key* rrset, uint32_t now); 181 182 #endif /* SERVICES_CACHE_DNS_H */ 183