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/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once
#include <sys/time.h>
#include <libknot/dname.h>
#include <libknot/codes.h>
#include "lib/cache/api.h"
#include "lib/zonecut.h"
#include "lib/nsrep.h"
/** Query flags */
struct kr_qflags {
bool NO_MINIMIZE : 1; /**< Don't minimize QNAME. */
bool NO_THROTTLE : 1; /**< No query/slow NS throttling. */
bool NO_IPV6 : 1; /**< Disable IPv6 */
bool NO_IPV4 : 1; /**< Disable IPv4 */
bool TCP : 1; /**< Use TCP for this query. */
bool RESOLVED : 1; /**< Query is resolved. Note that kr_query gets
* RESOLVED before following a CNAME chain; see .CNAME. */
bool AWAIT_IPV4 : 1; /**< Query is waiting for A address. */
bool AWAIT_IPV6 : 1; /**< Query is waiting for AAAA address. */
bool AWAIT_CUT : 1; /**< Query is waiting for zone cut lookup */
bool SAFEMODE : 1; /**< Don't use fancy stuff (EDNS, 0x20, ...) */
bool CACHED : 1; /**< Query response is cached. */
bool NO_CACHE : 1; /**< No cache for lookup; exception: finding NSs and subqueries. */
bool EXPIRING : 1; /**< Query response is cached, but expiring. */
bool ALLOW_LOCAL : 1; /**< Allow queries to local or private address ranges. */
bool DNSSEC_WANT : 1; /**< Want DNSSEC secured answer; exception: +cd,
* i.e. knot_wire_set_cd(request->answer->wire). */
bool DNSSEC_BOGUS : 1; /**< Query response is DNSSEC bogus. */
bool DNSSEC_INSECURE : 1;/**< Query response is DNSSEC insecure. */
bool DNSSEC_CD : 1; /**< Instruction to set CD bit in request. */
bool STUB : 1; /**< Stub resolution, accept received answer as solved. */
bool ALWAYS_CUT : 1; /**< Always recover zone cut (even if cached). */
bool DNSSEC_WEXPAND : 1; /**< Query response has wildcard expansion. */
bool PERMISSIVE : 1; /**< Permissive resolver mode. */
bool STRICT : 1; /**< Strict resolver mode. */
bool BADCOOKIE_AGAIN : 1;/**< Query again because bad cookie returned. */
bool CNAME : 1; /**< Query response contains CNAME in answer section. */
bool REORDER_RR : 1; /**< Reorder cached RRs. */
bool TRACE : 1; /**< Also log answers if --verbose. */
bool NO_0X20 : 1; /**< Disable query case randomization . */
bool DNSSEC_NODS : 1; /**< DS non-existance is proven */
bool DNSSEC_OPTOUT : 1; /**< Closest encloser proof has optout */
bool NONAUTH : 1; /**< Non-authoritative in-bailiwick records are enough.
* TODO: utilize this also outside cache. */
bool FORWARD : 1; /**< Forward all queries to upstream; validate answers. */
bool DNS64_MARK : 1; /**< Internal mark for dns64 module. */
bool CACHE_TRIED : 1; /**< Internal to cache module. */
bool NO_NS_FOUND : 1; /**< No valid NS found during last PRODUCE stage. */
};
/** Combine flags together. This means set union for simple flags. */
KR_EXPORT
void kr_qflags_set(struct kr_qflags *fl1, struct kr_qflags fl2);
/** Remove flags. This means set-theoretic difference. */
KR_EXPORT
void kr_qflags_clear(struct kr_qflags *fl1, struct kr_qflags fl2);
/** Callback for serve-stale decisions.
* @param ttl the expired TTL (i.e. it's < 0)
* @return the adjusted TTL (typically 1) or < 0.
*/
typedef int32_t (*kr_stale_cb)(int32_t ttl, const knot_dname_t *owner, uint16_t type,
const struct kr_query *qry);
/**
* Single query representation.
*/
struct kr_query {
struct kr_query *parent;
knot_dname_t *sname; /**< The name to resolve - lower-cased, uncompressed. */
uint16_t stype;
uint16_t sclass;
uint16_t id;
struct kr_qflags flags, forward_flags;
uint32_t secret;
uint16_t fails;
uint16_t reorder; /**< Seed to reorder (cached) RRs in answer or zero. */
uint64_t creation_time_mono; /* The time of query's creation (milliseconds).
* Or time of creation of an oldest
* ancestor if it is a subquery. */
uint64_t timestamp_mono; /**< Time of query created or time of
* query to upstream resolver (milliseconds). */
struct timeval timestamp; /**< Real time for TTL+DNSSEC checks (.tv_sec only). */
struct kr_zonecut zone_cut;
struct kr_layer_pickle *deferred;
uint32_t uid; /**< Query iteration number, unique within the kr_rplan. */
/** Pointer to the query that originated this one because of following a CNAME (or NULL). */
struct kr_query *cname_parent;
struct kr_request *request; /**< Parent resolution request. */
kr_stale_cb stale_cb; /**< See the type */
/* Beware: this must remain the last, because of lua bindings. */
struct kr_nsrep ns;
};
/** @cond internal Array of queries. */
typedef array_t(struct kr_query *) kr_qarray_t;
/* @endcond */
/**
* Query resolution plan structure.
*
* The structure most importantly holds the original query, answer and the
* list of pending queries required to resolve the original query.
* It also keeps a notion of current zone cut.
*/
struct kr_rplan {
kr_qarray_t pending; /**< List of pending queries. */
kr_qarray_t resolved; /**< List of resolved queries. */
struct kr_request *request; /**< Parent resolution request. */
knot_mm_t *pool; /**< Temporary memory pool. */
uint32_t next_uid; /**< Next value for kr_query::uid (incremental). */
};
/**
* Initialize resolution plan (empty).
* @param rplan plan instance
* @param request resolution request
* @param pool ephemeral memory pool for whole resolution
*/
KR_EXPORT
int kr_rplan_init(struct kr_rplan *rplan, struct kr_request *request, knot_mm_t *pool);
/**
* Deinitialize resolution plan, aborting any uncommited transactions.
* @param rplan plan instance
*/
KR_EXPORT
void kr_rplan_deinit(struct kr_rplan *rplan);
/**
* Return true if the resolution plan is empty (i.e. finished or initialized)
* @param rplan plan instance
* @return true or false
*/
KR_EXPORT KR_PURE
bool kr_rplan_empty(struct kr_rplan *rplan);
/**
* Push empty query to the top of the resolution plan.
* @note This query serves as a cookie query only.
* @param rplan plan instance
* @param parent query parent (or NULL)
* @return query instance or NULL
*/
KR_EXPORT
struct kr_query *kr_rplan_push_empty(struct kr_rplan *rplan,
struct kr_query *parent);
/**
* Push a query to the top of the resolution plan.
* @note This means that this query takes precedence before all pending queries.
* @param rplan plan instance
* @param parent query parent (or NULL)
* @param name resolved name
* @param cls resolved class
* @param type resolved type
* @return query instance or NULL
*/
KR_EXPORT
struct kr_query *kr_rplan_push(struct kr_rplan *rplan, struct kr_query *parent,
const knot_dname_t *name, uint16_t cls, uint16_t type);
/**
* Pop existing query from the resolution plan.
* @note Popped queries are not discarded, but moved to the resolved list.
* @param rplan plan instance
* @param qry resolved query
* @return 0 or an error
*/
KR_EXPORT
int kr_rplan_pop(struct kr_rplan *rplan, struct kr_query *qry);
/**
* Return true if resolution chain satisfies given query.
*/
KR_EXPORT KR_PURE
bool kr_rplan_satisfies(struct kr_query *closure, const knot_dname_t *name, uint16_t cls, uint16_t type);
/** Return last resolved query. */
KR_EXPORT KR_PURE
struct kr_query *kr_rplan_resolved(struct kr_rplan *rplan);
/**
* Return last query (either currently being solved or last resolved).
* This is necessary to retrieve the last query in case of resolution failures (e.g. time limit reached).
*/
KR_EXPORT KR_PURE
struct kr_query *kr_rplan_last(struct kr_rplan *rplan);
/**
* Check if a given query already resolved.
* @param rplan plan instance
* @param parent query parent (or NULL)
* @param name resolved name
* @param cls resolved class
* @param type resolved type
* @return query instance or NULL
*/
KR_EXPORT KR_PURE
struct kr_query *kr_rplan_find_resolved(struct kr_rplan *rplan, struct kr_query *parent,
const knot_dname_t *name, uint16_t cls, uint16_t type);
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