Data Structures | Macros | Functions
dns.h File Reference

This file contains the DNS cache. More...

#include "util/storage/lruhash.h"
#include "util/data/msgreply.h"

Data Structures

struct  dns_msg
 Region allocated message reply. More...
 

Macros

#define DNSCACHE_STORE_ZEROTTL   0x100000
 Flags to control behavior of dns_cache_store() and dns_cache_store_msg(). More...
 

Functions

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)
 Allocate a dns_msg with malloc/alloc structure and store in dns 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)
 Store message in the cache. More...
 
struct delegptdns_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 a delegation from the cache. More...
 
struct dns_msgtomsg (struct module_env *env, struct query_info *q, struct reply_info *r, struct regional *region, time_t now, struct regional *scratch)
 generate dns_msg from cached message More...
 
struct dns_msgdns_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 cached message. More...
 
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...
 
struct dns_msgdns_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_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...
 
struct msgreply_entrymsg_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 the returned nonNULL entry is locked and has to be unlocked by the caller More...
 

Detailed Description

This file contains the DNS cache.

Macro Definition Documentation

◆ DNSCACHE_STORE_ZEROTTL

#define DNSCACHE_STORE_ZEROTTL   0x100000

Flags to control behavior of dns_cache_store() and dns_cache_store_msg().

Must be an unsigned 32-bit value larger than 0xffff Allow caching a DNS message with a zero TTL.

Referenced by dns_cache_store_msg().

Function Documentation

◆ 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 
)

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

Parameters
envenvironment, with alloc structure and dns cache.
qinfquery info, the query for which answer is stored. this is allocated in a region, and will be copied to malloc area before insertion.
repreply 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_referralIf 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.
leewayTTL value, if not 0, other rrsets are considered expired that many seconds before actual TTL expiry.
psideif 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.
regionregion to allocate better entries from cache into. (used when is_referral is false).
flagsflags 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).
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_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(), load_msg(), processFinished(), and storeQueryInCache().

◆ 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 
)

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
envmodule environment with the DNS cache.
qinfoquery info
hashhash over qinfo.
repreply info, together with qinfo makes up the message. Adjusts the reply info TTLs to absolute time.
leewayTTL value, if not 0, other rrsets are considered expired that many seconds before actual TTL expiry.
psideif 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.
qrepmessage that can be altered with better rrs from cache.
flagscustomization flags for the cache policy.
regionto 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, module_env::now, query_info_entrysetup(), reply_info::ref, 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().

◆ 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 
)

Find a delegation from the cache.

Parameters
envmodule environment with the DNS cache.
qnamequery name.
qnamelenlength of qname.
qtypequery type.
qclassquery class.
regionwhere to allocate result delegation.
msgif not NULL, delegation message is returned here, synthesized from the cache.
timenowthe time now, for checking if TTL on cache entries is OK.
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,
struct regional scratch 
)

generate dns_msg from cached message

Parameters
envmodule environment with the DNS cache. NULL if the LRU from cache does not need to be touched.
qquery info, contains qname that will make up the dns message.
rreply info that, together with qname, will make up the dns message.
regionwhere to allocate dns message.
nowthe time now, for check if TTL on cache entry is ok.
scratchwhere to allocate temporary data.

References reply_info::an_numrrsets, reply_info::ar_numrrsets, reply_info::authoritative, reply_info::flags, gen_dns_msg(), LDNS_RR_TYPE_CNAME, LDNS_RR_TYPE_DNAME, reply_info::ns_numrrsets, packed_rrset_copy_region(), reply_info::prefetch_ttl, PREFETCH_TTL_CALC, reply_info::qdcount, reply_info::ref, dns_msg::rep, reply_all_rrsets_secure(), reply_check_cname_chain(), ub_packed_rrset_key::rk, rrset_array_lock(), rrset_array_unlock(), rrset_array_unlock_touch(), module_env::rrset_cache, reply_info::rrset_count, reply_info::rrsets, sec_status_secure, reply_info::security, reply_info::ttl, and packed_rrset_key::type.

Referenced by dns_cache_lookup().

◆ 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 
)

Find cached message.

Parameters
envmodule environment with the DNS cache.
qnamequery name.
qnamelenlength of qname.
qtypequery type.
qclassquery class.
flagsflags with BIT_CD for AAAA queries in dns64 translation.
regionwhere to allocate result.
scratchwhere to allocate temporary data.
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(), slabhash_lookup(), synth_dname_msg(), tomsg(), and val_rrset_wildcard().

◆ 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
envmodule environment with rrset cache
qclasswhich class to look in.
regionwhere to store new dp info.
dpdelegation point to fill missing entries.
Returns
false on alloc failure.

References delegpt_add_neg_msg(), delegpt_add_rrset_A(), delegpt_add_rrset_AAAA(), ub_packed_rrset_key::entry, msgreply_entry::entry, delegpt_ns::lame, LDNS_RR_TYPE_A, LDNS_RR_TYPE_AAAA, lruhash_entry::lock, log_nametypeclass(), msg_cache_lookup(), delegpt_ns::name, delegpt_ns::namelen, delegpt_ns::next, module_env::now, delegpt::nslist, module_env::rrset_cache, rrset_cache_lookup(), and VERB_ALGO.

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
qnamequery section name
qnamelenlen of qname
qtypequery section type
qclassquery section class
regionwhere to alloc.
capacitynumber 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, regional_alloc(), regional_alloc_init(), regional_alloc_zero(), dns_msg::rep, RR_COUNT_MAX, and reply_info::rrsets.

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
msgmsg to put it in.
regionregion to alloc in
rrsetto add in authority section
nownow.
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_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
envmodule environment with caches and time.
qinfoquery info for the query that needs adjustment.
adjusttime in seconds to add to the prefetch_leeway.
flagsflags 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().

◆ 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 the returned nonNULL entry is locked and has to be unlocked by the caller

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 cache_fill_missing(), dns_cache_prefetch_adjust(), error_response_cache(), and find_add_addrs().