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/*
* 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 REGENTS 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).
* @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, uint32_t leeway, int pside,
struct regional* region);
/**
* 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, uint32_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, uint32_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 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,
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, uint32_t now);
#endif /* SERVICES_CACHE_DNS_H */
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