This file contains the DNS cache. More...

#include "config.h"
#include "iterator/iter_delegpt.h"
#include "iterator/iter_utils.h"
#include "validator/val_nsec.h"
#include "validator/val_utils.h"
#include "services/cache/dns.h"
#include "services/cache/rrset.h"
#include "util/data/msgparse.h"
#include "util/data/msgreply.h"
#include "util/data/packed_rrset.h"
#include "util/data/dname.h"
#include "util/module.h"
#include "util/net_help.h"
#include "util/regional.h"
#include "util/config_file.h"
#include "sldns/sbuffer.h"

Functions
static void	store_rrsets (struct module_env env, struct reply_info rep, time_t now, time_t leeway, int pside, struct reply_info qrep, struct regional region, time_t qstarttime)
	store rrsets in the rrset cache. More...

void	msg_cache_remove (struct module_env env, uint8_t qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, uint16_t flags)
	delete message from message cache More...

void	dns_cache_store_msg (struct module_env env, struct query_info qinfo, hashvalue_type hash, struct reply_info rep, time_t leeway, int pside, struct reply_info qrep, uint32_t flags, struct regional *region, time_t qstarttime)
	Store message in the cache. More...

static int	rrset_expired_above (struct module_env env, uint8_t qname, size_t qnamelen, uint16_t searchtype, uint16_t qclass, time_t now, uint8_t *expiretop, size_t expiretoplen)
	see if an rrset is expired above the qname, return upper qname.

static struct ub_packed_rrset_key *	find_closest_of_type (struct module_env env, uint8_t qname, size_t qnamelen, uint16_t qclass, time_t now, uint16_t searchtype, int stripfront, int noexpiredabove, uint8_t *expiretop, size_t expiretoplen)
	find closest NS or DNAME and returns the rrset (locked)

static void	addr_to_additional (struct ub_packed_rrset_key rrset, struct regional region, struct dns_msg *msg, time_t now)
	add addr to additional section

struct msgreply_entry *	msg_cache_lookup (struct module_env env, uint8_t qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, uint16_t flags, time_t now, int wr)
	lookup message in message cache More...

static int	find_add_addrs (struct module_env env, uint16_t qclass, struct regional region, struct delegpt dp, time_t now, struct dns_msg *msg)
	find and add A and AAAA records for nameservers in delegpt

int	cache_fill_missing (struct module_env env, uint16_t qclass, struct regional region, struct delegpt *dp)
	find and add A and AAAA records for missing nameservers in delegpt More...

static void	find_add_ds (struct module_env env, struct regional region, struct dns_msg msg, struct delegpt dp, time_t now)
	find and add DS or NSEC to delegation msg

struct dns_msg *	dns_msg_create (uint8_t qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, struct regional region, size_t capacity)
	Utility, create new, unpacked data structure for cache response. More...

int	dns_msg_authadd (struct dns_msg msg, struct regional region, struct ub_packed_rrset_key *rrset, time_t now)
	Add rrset to authority section in unpacked dns_msg message. More...

int	dns_msg_ansadd (struct dns_msg msg, struct regional region, struct ub_packed_rrset_key *rrset, time_t now)
	Add rrset to authority section in unpacked dns_msg message. More...

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 now, int noexpiredabove, uint8_t expiretop, size_t expiretoplen)
	Find a delegation from the cache. More...

static struct dns_msg *	gen_dns_msg (struct regional region, struct query_info q, size_t num)
	allocate dns_msg from query_info and reply_info

struct dns_msg *	tomsg (struct module_env env, struct query_info q, struct reply_info r, struct regional region, time_t now, int allow_expired, struct regional *scratch)
	generate dns_msg from cached message More...

struct dns_msg *	dns_msg_deepcopy_region (struct dns_msg origin, struct regional region)
	Deep copy a dns_msg to a region. More...

static struct dns_msg *	rrset_msg (struct ub_packed_rrset_key rrset, struct regional region, time_t now, struct query_info *q)
	synthesize RRset-only response from cached RRset item

static struct dns_msg *	synth_dname_msg (struct ub_packed_rrset_key rrset, struct regional region, time_t now, struct query_info q, enum sec_status sec_status)
	synthesize DNAME+CNAME response from cached DNAME item

static struct dns_msg *	fill_any (struct module_env env, uint8_t qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, struct regional *region)
	Fill TYPE_ANY response with some data from cache.

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, int no_partial, uint8_t *dpname, size_t dpnamelen)
	Find cached message. More...

int	dns_cache_store (struct module_env env, struct query_info msgqinf, struct reply_info msgrep, int is_referral, time_t leeway, int pside, struct regional region, uint32_t flags, time_t qstarttime)
	Allocate a dns_msg with malloc/alloc structure and store in dns cache. More...

int	dns_cache_prefetch_adjust (struct module_env env, struct query_info qinfo, time_t adjust, uint16_t flags)
	Adjust the prefetch_ttl for a cached message. More...

Detailed Description

This file contains the DNS cache.

Function Documentation

◆ store_rrsets()

static void store_rrsets	(	struct module_env *	env,
		struct reply_info *	rep,
		time_t	now,
		time_t	leeway,
		int	pside,
		struct reply_info *	qrep,
		struct regional *	region,
		time_t	qstarttime
	)

static

store rrsets in the rrset cache.

Parameters

env	module environment with caches.
rep	contains list of rrsets to store.
now	current time.
leeway	during prefetch how much leeway to update TTLs. This makes rrsets (other than type NS) timeout sooner so they get updated with a new full TTL. Type NS does not get this, because it must not be refreshed from the child domain, but keep counting down properly.
pside	if from parentside discovered NS, so that its NS is okay in a prefetch situation to be updated (without becoming sticky).
qrep	update rrsets here if cache is better
region	for qrep allocs.
qstarttime	time when delegations were looked up, this is perhaps earlier than the time in now. The time is used to determine if RRsets of type NS have expired, so that they can only be updated using lookups of delegation points that did not use them, since they had expired then.

References module_env::alloc, lruhash_entry::data, ub_packed_rrset_key::entry, rrset_ref::id, ub_packed_rrset_key::id, rrset_ref::key, LDNS_RR_TYPE_NS, lruhash_entry::lock, packed_rrset_copy_region(), reply_info::prefetch_ttl, PREFETCH_TTL_CALC, reply_info::ref, ub_packed_rrset_key::rk, module_env::rrset_cache, rrset_cache_update(), reply_info::rrset_count, reply_info::rrsets, SERVE_EXPIRED_TTL, reply_info::serve_expired_ttl, reply_info::ttl, packed_rrset_data::ttl, and packed_rrset_key::type.

Referenced by dns_cache_store_msg().

◆ msg_cache_remove()

void msg_cache_remove	(	struct module_env *	env,
		uint8_t *	qname,
		size_t	qnamelen,
		uint16_t	qtype,
		uint16_t	qclass,
		uint16_t	flags
	)

delete message from message cache

Remove entry from the message cache.

References query_info::local_alias, module_env::msg_cache, query_info::qclass, query_info::qname, query_info::qname_len, query_info::qtype, query_info_hash(), and slabhash_remove().

Referenced by dns_cache_store_msg().

◆ dns_cache_store_msg()

void dns_cache_store_msg	(	struct module_env *	env,
		struct query_info *	qinfo,
		hashvalue_type	hash,
		struct reply_info *	rep,
		time_t	leeway,
		int	pside,
		struct reply_info *	qrep,
		uint32_t	flags,
		struct regional *	region,
		time_t	qstarttime
	)

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.

Parameters

env	module environment with the DNS cache.
qinfo	query info
hash	hash over qinfo.
rep	reply info, together with qinfo makes up the message. Adjusts the reply info TTLs to absolute time.
leeway	TTL value, if not 0, other rrsets are considered expired that many seconds before actual TTL expiry.
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.
qrep	message that can be altered with better rrs from cache.
flags	customization flags for the cache policy.
qstarttime	time when the query was started, and thus when the delegations were looked up.
region	to allocate into for qmsg.

References module_env::alloc, DNSCACHE_STORE_ZEROTTL, msgreply_entry::entry, rrset_ref::id, ub_packed_rrset_key::id, rrset_ref::key, log_err(), module_env::msg_cache, msg_cache_remove(), module_env::now, query_info::qclass, query_info::qname, query_info::qname_len, query_info::qtype, query_info_entrysetup(), reply_info::ref, reply_info_delete(), reply_info_set_ttls(), reply_info_sortref(), reply_info::rrset_count, reply_info::rrsets, slabhash_insert(), store_rrsets(), reply_info::ttl, VERB_ALGO, and verbose().

Referenced by dns_cache_store().

◆ msg_cache_lookup()

struct msgreply_entry* msg_cache_lookup	(	struct module_env *	env,
		uint8_t *	qname,
		size_t	qnamelen,
		uint16_t	qtype,
		uint16_t	qclass,
		uint16_t	flags,
		time_t	now,
		int	wr
	)

lookup message in message cache

lookup message in message cache the returned nonNULL entry is locked and has to be unlocked by the caller

References lruhash_entry::data, lruhash_entry::key, query_info::local_alias, lruhash_entry::lock, module_env::msg_cache, query_info::qclass, query_info::qname, query_info::qname_len, query_info::qtype, query_info_hash(), and slabhash_lookup().

Referenced by dns_cache_prefetch_adjust(), error_response_cache(), and find_add_addrs().

◆ cache_fill_missing()

int cache_fill_missing	(	struct module_env *	env,
		uint16_t	qclass,
		struct regional *	region,
		struct delegpt *	dp
	)

find and add A and AAAA records for missing nameservers in delegpt

Parameters

env	module environment with rrset cache
qclass	which class to look in.
region	where to store new dp info.
dp	delegation point to fill missing entries.

Returns: false on alloc failure.

References delegpt_ns::cache_lookup_count, delegpt_ns::next, module_env::now, and delegpt::nslist.

Referenced by error_supers().

◆ dns_msg_create()

struct dns_msg* dns_msg_create	(	uint8_t *	qname,
		size_t	qnamelen,
		uint16_t	qtype,
		uint16_t	qclass,
		struct regional *	region,
		size_t	capacity
	)

Utility, create new, unpacked data structure for cache response.

QR bit set, no AA. Query set as indicated. Space for number of rrsets.

Parameters

qname	query section name
qnamelen	len of qname
qtype	query section type
qclass	query section class
region	where to alloc.
capacity	number of rrsets space to create in the array.

Returns: new dns_msg struct or NULL on mem fail.

References BIT_QR, reply_info::flags, query_info::local_alias, query_info::qclass, reply_info::qdcount, dns_msg::qinfo, query_info::qname, query_info::qname_len, query_info::qtype, reply_info::reason_bogus, regional_alloc(), regional_alloc_init(), regional_alloc_zero(), dns_msg::rep, and RR_COUNT_MAX.

Referenced by dns_cache_find_delegation(), fill_any(), and val_find_DS().

◆ dns_msg_authadd()

int dns_msg_authadd	(	struct dns_msg *	msg,
		struct regional *	region,
		struct ub_packed_rrset_key *	rrset,
		time_t	now
	)

Add rrset to authority section in unpacked dns_msg message.

Must have enough space left, does not grow the array.

Parameters

msg	msg to put it in.
region	region to alloc in
rrset	to add in authority section
now	now.

Returns: true if worked, false on fail

References reply_info::ns_numrrsets, packed_rrset_copy_region(), dns_msg::rep, reply_info::rrset_count, and reply_info::rrsets.

Referenced by add_soa(), and dns_cache_find_delegation().

◆ dns_msg_ansadd()

int dns_msg_ansadd	(	struct dns_msg *	msg,
		struct regional *	region,
		struct ub_packed_rrset_key *	rrset,
		time_t	now
	)

Add rrset to authority section in unpacked dns_msg message.

Must have enough space left, does not grow the array.

Parameters

msg	msg to put it in.
region	region to alloc in
rrset	to add in authority section
now	now.

Returns: true if worked, false on fail

References reply_info::an_numrrsets, packed_rrset_copy_region(), dns_msg::rep, reply_info::rrset_count, and reply_info::rrsets.

◆ dns_cache_find_delegation()

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,
		int	noexpiredabove,
		uint8_t *	expiretop,
		size_t	expiretoplen
	)

Find a delegation from the cache.

Parameters

env	module environment with the DNS cache.
qname	query name.
qnamelen	length of qname.
qtype	query type.
qclass	query class.
region	where to allocate result delegation.
msg	if not NULL, delegation message is returned here, synthesized from the cache.
timenow	the time now, for checking if TTL on cache entries is OK.
noexpiredabove	if set, no expired NS rrsets above the one found are tolerated. It only returns delegations where the delegations above it are valid.
expiretop	if not NULL, name where check for expiry ends for noexpiredabove.
expiretoplen	length of expiretop dname.

Returns: new delegation or NULL on error or if not found in cache.

References packed_rrset_data::count, lruhash_entry::data, delegpt_create(), delegpt_rrset_add_ns(), delegpt_set_name(), packed_rrset_key::dname, dns_msg_authadd(), dns_msg_create(), ub_packed_rrset_key::entry, find_add_addrs(), find_add_ds(), find_closest_of_type(), LDNS_RR_TYPE_NS, lruhash_entry::lock, log_err(), and ub_packed_rrset_key::rk.

Referenced by answer_norec_from_cache(), and generate_parentside_target_query().

◆ tomsg()

struct dns_msg* tomsg	(	struct module_env *	env,
		struct query_info *	q,
		struct reply_info *	r,
		struct regional *	region,
		time_t	now,
		int	allow_expired,
		struct regional *	scratch
	)

generate dns_msg from cached message

Parameters

env	module environment with the DNS cache. NULL if the LRU from cache does not need to be touched.
q	query info, contains qname that will make up the dns message.
r	reply info that, together with qname, will make up the dns message.
region	where to allocate dns message.
now	the time now, for check if TTL on cache entry is ok.
allow_expired	if true and serve-expired is enabled, it will allow for expired dns_msg to be generated based on the configured serve-expired logic.
scratch	where to allocate temporary data.

References module_env::cfg, reply_info::flags, FLAGS_GET_RCODE, config_file::serve_expired_ttl, reply_info::serve_expired_ttl, and reply_info::ttl.

Referenced by dns_cache_lookup(), and mesh_serve_expired_lookup().

◆ dns_msg_deepcopy_region()

struct dns_msg* dns_msg_deepcopy_region	(	struct dns_msg *	origin,
		struct regional *	region
	)

Deep copy a dns_msg to a region.

Parameters

origin	the dns_msg to copy.
region	the region to copy all the data to.

Returns: the new dns_msg or NULL on malloc error.

References gen_dns_msg(), packed_rrset_copy_region(), dns_msg::qinfo, reply_info::reason_bogus_str, regional_strdup(), dns_msg::rep, reply_info::rrset_count, and reply_info::rrsets.

Referenced by val_inform_super().

◆ dns_cache_lookup()

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,
		int	no_partial,
		uint8_t *	dpname,
		size_t	dpnamelen
	)

Find cached message.

Parameters

env	module environment with the DNS cache.
qname	query name.
qnamelen	length of qname.
qtype	query type.
qclass	query class.
flags	flags with BIT_CD for AAAA queries in dns64 translation.
region	where to allocate result.
scratch	where to allocate temporary data.
no_partial	if true, only complete messages and not a partial one (with only the start of the CNAME chain and not the rest).
dpname	if not NULL, do not return NXDOMAIN above this name.
dpnamelen	length of dpname.

Returns: 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.

References lruhash_entry::data, ub_packed_rrset_key::entry, find_closest_of_type(), msgreply_entry::key, lruhash_entry::key, LDNS_RR_TYPE_CNAME, LDNS_RR_TYPE_DNAME, LDNS_RR_TYPE_DS, query_info::local_alias, lruhash_entry::lock, module_env::msg_cache, module_env::now, query_info::qclass, query_info::qname, query_info::qname_len, query_info::qtype, query_info_hash(), module_env::rrset_cache, rrset_cache_lookup(), rrset_msg(), sec_status_secure, sec_status_unchecked, slabhash_lookup(), synth_dname_msg(), tomsg(), and val_rrset_wildcard().

◆ dns_cache_store()

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,
		uint32_t	flags,
		time_t	qstarttime
	)

Allocate a dns_msg with malloc/alloc structure and store in dns cache.

Parameters

env	environment, with alloc structure and dns cache.
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.
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.
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.
leeway	TTL value, if not 0, other rrsets are considered expired that many seconds before actual TTL expiry.
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.
region	region to allocate better entries from cache into. (used when is_referral is false).
flags	flags with BIT_CD for AAAA queries in dns64 translation. The higher 16 bits are used internally to customize the cache policy. (See DNSCACHE_STORE_xxx flags).
qstarttime	time when the query was started, and thus when the delegations were looked up.

Returns: 0 on alloc error (out of memory).

References module_env::alloc, BIT_AA, BIT_CD, BIT_QR, BIT_RA, lruhash_entry::data, dns_cache_store_msg(), ub_packed_rrset_key::entry, reply_info::flags, rrset_ref::id, ub_packed_rrset_key::id, rrset_ref::key, LDNS_RR_TYPE_NS, memdup(), module_env::now, packed_rrset_ttl_add(), query_info::qname, query_info::qname_len, query_info_hash(), reply_info_copy(), reply_info_delete(), reply_info_parsedelete(), ub_packed_rrset_key::rk, module_env::rrset_cache, rrset_cache_update(), reply_info::rrset_count, reply_info::rrsets, and packed_rrset_key::type.

Referenced by iter_dns_store(), and storeQueryInCache().

◆ dns_cache_prefetch_adjust()

int dns_cache_prefetch_adjust	(	struct module_env *	env,
		struct query_info *	qinfo,
		time_t	adjust,
		uint16_t	flags
	)

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.

Parameters

env	module environment with caches and time.
qinfo	query info for the query that needs adjustment.
adjust	time in seconds to add to the prefetch_leeway.
flags	flags with BIT_CD for AAAA queries in dns64 translation.

Returns: false if not in cache. true if added.

References lruhash_entry::data, msgreply_entry::entry, lruhash_entry::lock, msg_cache_lookup(), module_env::now, reply_info::prefetch_ttl, query_info::qclass, query_info::qname, query_info::qname_len, and query_info::qtype.

Referenced by error_response_cache().

Functions

Detailed Description

Function Documentation

◆ store_rrsets()

◆ msg_cache_remove()

◆ dns_cache_store_msg()

◆ msg_cache_lookup()

◆ cache_fill_missing()

◆ dns_msg_create()

◆ dns_msg_authadd()

◆ dns_msg_ansadd()

◆ dns_cache_find_delegation()

◆ tomsg()

◆ dns_msg_deepcopy_region()

◆ dns_cache_lookup()

◆ dns_cache_store()

◆ dns_cache_prefetch_adjust()