/* * services/cache/dns.h - Cache services for DNS using msg and rrset caches. * * Copyright (c) 2007, NLnet Labs. All rights reserved. * * This software is open source. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the NLNET LABS nor the names of its contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** * \file * * This file contains the DNS cache. */ #ifndef SERVICES_CACHE_DNS_H #define SERVICES_CACHE_DNS_H #include "util/storage/lruhash.h" #include "util/data/msgreply.h" struct module_env; struct query_info; struct reply_info; struct regional; struct delegpt; /** * Region allocated message reply */ struct dns_msg { /** query info */ struct query_info qinfo; /** reply info - ptr to packed repinfo structure */ struct reply_info *rep; }; /** * Allocate a dns_msg with malloc/alloc structure and store in dns cache. * * @param env: environment, with alloc structure and dns cache. * @param qinf: query info, the query for which answer is stored. * this is allocated in a region, and will be copied to malloc area * before insertion. * @param rep: reply in dns_msg from dns_alloc_msg for example. * this is allocated in a region, and will be copied to malloc area * before insertion. * @param is_referral: If true, then the given message to be stored is a * referral. The cache implementation may use this as a hint. * It will store only the RRsets, not the message. * @param leeway: TTL value, if not 0, other rrsets are considered expired * that many seconds before actual TTL expiry. * @param pside: if true, information came from a server which was fetched * from the parentside of the zonecut. This means that the type NS * can be updated to full TTL even in prefetch situations. * @param region: region to allocate better entries from cache into. * (used when is_referral is false). * @param flags: flags with BIT_CD for AAAA queries in dns64 translation. * @return 0 on alloc error (out of memory). */ int dns_cache_store(struct module_env* env, struct query_info* qinf, struct reply_info* rep, int is_referral, time_t leeway, int pside, struct regional* region, uint16_t flags); /** * Store message in the cache. Stores in message cache and rrset cache. * Both qinfo and rep should be malloced and are put in the cache. * They should not be used after this call, as they are then in shared cache. * Does not return errors, they are logged and only lead to less cache. * * @param env: module environment with the DNS cache. * @param qinfo: query info * @param hash: hash over qinfo. * @param rep: reply info, together with qinfo makes up the message. * Adjusts the reply info TTLs to absolute time. * @param leeway: TTL value, if not 0, other rrsets are considered expired * that many seconds before actual TTL expiry. * @param pside: if true, information came from a server which was fetched * from the parentside of the zonecut. This means that the type NS * can be updated to full TTL even in prefetch situations. * @param qrep: message that can be altered with better rrs from cache. * @param region: to allocate into for qmsg. */ void dns_cache_store_msg(struct module_env* env, struct query_info* qinfo, hashvalue_t hash, struct reply_info* rep, time_t leeway, int pside, struct reply_info* qrep, struct regional* region); /** * Find a delegation from the cache. * @param env: module environment with the DNS cache. * @param qname: query name. * @param qnamelen: length of qname. * @param qtype: query type. * @param qclass: query class. * @param region: where to allocate result delegation. * @param msg: if not NULL, delegation message is returned here, synthesized * from the cache. * @param timenow: the time now, for checking if TTL on cache entries is OK. * @return new delegation or NULL on error or if not found in cache. */ struct delegpt* dns_cache_find_delegation(struct module_env* env, uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, struct regional* region, struct dns_msg** msg, time_t timenow); /** * Find cached message * @param env: module environment with the DNS cache. * @param qname: query name. * @param qnamelen: length of qname. * @param qtype: query type. * @param qclass: query class. * @param flags: flags with BIT_CD for AAAA queries in dns64 translation. * @param region: where to allocate result. * @param scratch: where to allocate temporary data. * @return new response message (alloced in region, rrsets do not have IDs). * or NULL on error or if not found in cache. * TTLs are made relative to the current time. */ struct dns_msg* dns_cache_lookup(struct module_env* env, uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, uint16_t flags, struct regional* region, struct regional* scratch); /** * find and add A and AAAA records for missing nameservers in delegpt * @param env: module environment with rrset cache * @param qclass: which class to look in. * @param region: where to store new dp info. * @param dp: delegation point to fill missing entries. * @return false on alloc failure. */ int cache_fill_missing(struct module_env* env, uint16_t qclass, struct regional* region, struct delegpt* dp); /** * Utility, create new, unpacked data structure for cache response. * QR bit set, no AA. Query set as indicated. Space for number of rrsets. * @param qname: query section name * @param qnamelen: len of qname * @param qtype: query section type * @param qclass: query section class * @param region: where to alloc. * @param capacity: number of rrsets space to create in the array. * @return new dns_msg struct or NULL on mem fail. */ struct dns_msg* dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, struct regional* region, size_t capacity); /** * Add rrset to authority section in unpacked dns_msg message. Must have enough * space left, does not grow the array. * @param msg: msg to put it in. * @param region: region to alloc in * @param rrset: to add in authority section * @param now: now. * @return true if worked, false on fail */ int dns_msg_authadd(struct dns_msg* msg, struct regional* region, struct ub_packed_rrset_key* rrset, time_t now); /** * Adjust the prefetch_ttl for a cached message. This adds a value to the * prefetch ttl - postponing the time when it will be prefetched for future * incoming queries. * @param env: module environment with caches and time. * @param qinfo: query info for the query that needs adjustment. * @param adjust: time in seconds to add to the prefetch_leeway. * @param flags: flags with BIT_CD for AAAA queries in dns64 translation. * @return false if not in cache. true if added. */ int dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo, time_t adjust, uint16_t flags); #endif /* SERVICES_CACHE_DNS_H */