dns.c File Reference

This file contains the DNS cache. More...

#include "config.h"
#include "iterator/iter_delegpt.h"
#include "services/cache/dns.h"
#include "services/cache/rrset.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"

Functions

static void store_rrsets (struct module_env *env, struct reply_info *rep, uint32_t now)
 store rrsets in the rrset cache.
void dns_cache_store_msg (struct module_env *env, struct query_info *qinfo, hashvalue_t hash, struct reply_info *rep)
 Store message in the cache.
static struct ub_packed_rrset_keycopy_rrset (struct ub_packed_rrset_key *key, struct regional *region, uint32_t now)
 allocate rrset in region - no more locks needed
static struct ub_packed_rrset_keyfind_closest_of_type (struct module_env *env, uint8_t *qname, size_t qnamelen, uint16_t qclass, uint32_t now, uint16_t searchtype, int stripfront)
 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, uint32_t now)
 add addr to additional section
static int find_add_addrs (struct module_env *env, uint16_t qclass, struct regional *region, struct delegpt *dp, uint32_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
static void find_add_ds (struct module_env *env, struct regional *region, struct dns_msg *msg, struct delegpt *dp, uint32_t now)
 find and add DS or NSEC to delegation msg
static struct dns_msgcreate_msg (uint8_t *qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, struct regional *region, struct ub_packed_rrset_key *nskey, struct packed_rrset_data *nsdata, uint32_t now)
 create referral message with NS and query
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, uint32_t now)
 Find a delegation from the cache.
static struct dns_msggen_dns_msg (struct regional *region, struct query_info *q, size_t num)
 allocate dns_msg from query_info and reply_info
static struct dns_msgtomsg (struct module_env *env, struct msgreply_entry *e, struct reply_info *r, struct regional *region, uint32_t now, struct regional *scratch)
 generate dns_msg from cached message
static struct dns_msgrrset_msg (struct ub_packed_rrset_key *rrset, struct regional *region, uint32_t now, struct query_info *q)
 synthesize RRset-only response from cached RRset item
static struct dns_msgsynth_dname_msg (struct ub_packed_rrset_key *rrset, struct regional *region, uint32_t now, struct query_info *q)
 synthesize DNAME+CNAME response from cached DNAME item
struct dns_msgdns_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 cached message.
int dns_cache_store (struct module_env *env, struct query_info *msgqinf, struct reply_info *msgrep, int is_referral)
 Allocate a dns_msg with malloc/alloc structure and store in dns cache.


Detailed Description

This file contains the DNS cache.


Function Documentation

static void store_rrsets ( struct module_env env,
struct reply_info rep,
uint32_t  now 
) [static]

store rrsets in the rrset cache.

Parameters:
env,: module environment with caches.
rep,: contains list of rrsets to store.
now,: current time.

References module_env::alloc, ub_packed_rrset_key::id, rrset_ref::id, rrset_ref::key, reply_info::ref, module_env::rrset_cache, rrset_cache_update(), reply_info::rrset_count, and reply_info::rrsets.

Referenced by dns_cache_store_msg().

void dns_cache_store_msg ( struct module_env env,
struct query_info qinfo,
hashvalue_t  hash,
struct reply_info rep 
)

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.

References module_env::alloc, msgreply_entry::entry, ub_packed_rrset_key::id, rrset_ref::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().

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_add_rrset_A(), delegpt_add_rrset_AAAA(), ub_packed_rrset_key::entry, lruhash_entry::lock, log_nametypeclass(), delegpt_ns::name, delegpt_ns::namelen, delegpt_ns::next, module_env::now, delegpt::nslist, delegpt_ns::resolved, module_env::rrset_cache, rrset_cache_lookup(), and VERB_ALGO.

Referenced by processQueryResponse().

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 
) [read]

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

References create_msg(), lruhash_entry::data, delegpt_create(), delegpt_rrset_add_ns(), delegpt_set_name(), packed_rrset_key::dname, ub_packed_rrset_key::entry, find_add_addrs(), find_add_ds(), find_closest_of_type(), lruhash_entry::lock, log_err(), and ub_packed_rrset_key::rk.

Referenced by answer_norec_from_cache(), and processInitRequest().

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 
) [read]

Find cached message.

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.
scratch,: where 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(), lruhash_entry::key, msgreply_entry::key, 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(), rrset_trust_add_AA, rrset_trust_add_noAA, slabhash_lookup(), synth_dname_msg(), tomsg(), and packed_rrset_data::trust.

Referenced by processInitRequest().

int dns_cache_store ( struct module_env env,
struct query_info qinf,
struct reply_info rep,
int  is_referral 
)

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.
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, ub_packed_rrset_key::id, rrset_ref::id, rrset_ref::key, memdup(), module_env::now, packed_rrset_ttl_add(), query_info::qname, query_info::qname_len, query_info_hash(), reply_info_copy(), reply_info_parsedelete(), module_env::rrset_cache, rrset_cache_update(), reply_info::rrset_count, and reply_info::rrsets.

Referenced by iter_dns_store(), and processFinished().


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