adb.h File Reference

DNS Address Database. More...

#include <isc/lang.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/sockaddr.h>
#include <dns/types.h>
#include <dns/view.h>

Go to the source code of this file.

Data Structures

struct dns_adbfind

Represents a lookup for a single name. More...

struct dns_adbaddrinfo

The answers to queries come back as a list of these. More...

Defines

#define DNS_ADB_H   1

#define DNS_ADBFIND_MAGIC   ISC_MAGIC('a','d','b','H')

#define DNS_ADBFIND_VALID(x)   ISC_MAGIC_VALID(x, DNS_ADBFIND_MAGIC)

#define DNS_ADBADDRINFO_MAGIC   ISC_MAGIC('a','d','A','I')

#define DNS_ADBADDRINFO_VALID(x)   ISC_MAGIC_VALID(x, DNS_ADBADDRINFO_MAGIC)

#define DNS_ADBFIND_INET   0x00000001

Return addresses of type INET.

#define DNS_ADBFIND_INET6   0x00000002

Return addresses of type INET6.

#define DNS_ADBFIND_ADDRESSMASK   0x00000003

#define DNS_ADBFIND_EMPTYEVENT   0x00000004

Only schedule an event if no addresses are known. Must set _WANTEVENT for this to be meaningful.

#define DNS_ADBFIND_WANTEVENT   0x00000008

An event is desired. Check this bit in the returned find to see if one will actually be generated.

#define DNS_ADBFIND_AVOIDFETCHES   0x00000010

If set, fetches will not be generated unless no addresses are available in any of the address families requested.

#define DNS_ADBFIND_STARTATZONE   0x00000020

Fetches will start using the closest zone data or use the root servers. This is useful for reestablishing glue that has expired.

#define DNS_ADBFIND_GLUEOK   0x00000040

Glue or hints are ok. These are used when matching names already in the adb, and when dns databases are searched.

#define DNS_ADBFIND_HINTOK   0x00000080

Glue or hints are ok. These are used when matching names already in the adb, and when dns databases are searched.

#define DNS_ADBFIND_RETURNLAME   0x00000100

Return lame servers in a find, so that all addresses are returned.

#define DNS_ADBFIND_LAMEPRUNED   0x00000200

Only schedule an event if no addresses are known. Must set _WANTEVENT for this to be meaningful.

#define DNS_ADB_RTTADJDEFAULT   7

default scale

#define DNS_ADB_RTTADJREPLACE   0

replace with our rtt

#define DNS_ADB_RTTADJAGE   10

age this rtt

Typedefs

typedef struct dns_adbname dns_adbname_t

Functions

isc_result_t dns_adb_create (isc_mem_t *mem, dns_view_t *view, isc_timermgr_t *tmgr, isc_taskmgr_t *taskmgr, dns_adb_t **newadb)

Create a new ADB.

void dns_adb_attach (dns_adb_t *adb, dns_adb_t **adbp)

void dns_adb_detach (dns_adb_t **adb)

Attach to an 'adb' to 'adbp'.

void dns_adb_whenshutdown (dns_adb_t *adb, isc_task_t *task, isc_event_t **eventp)

Delete the ADB. Sets *ADB to NULL. Cancels any outstanding requests.

void dns_adb_shutdown (dns_adb_t *adb)

Send '*eventp' to 'task' when 'adb' has shutdown.

isc_result_t dns_adb_createfind (dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, void *arg, dns_name_t *name, dns_name_t *qname, dns_rdatatype_t qtype, unsigned int options, isc_stdtime_t now, dns_name_t *target, in_port_t port, dns_adbfind_t **find)

isc_result_t dns_adb_createfind2 (dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, void *arg, dns_name_t *name, dns_name_t *qname, dns_rdatatype_t qtype, unsigned int options, isc_stdtime_t now, dns_name_t *target, in_port_t port, unsigned int depth, isc_counter_t *qc, dns_adbfind_t **find)

Main interface for clients. The adb will look up the name given in "name" and will build up a list of found addresses, and perhaps start internal fetches to resolve names that are unknown currently.

void dns_adb_cancelfind (dns_adbfind_t *find)

Cancels the find, and sends the event off to the caller.

void dns_adb_destroyfind (dns_adbfind_t **find)

Destroys the find reference.

void dns_adb_dump (dns_adb_t *adb, FILE *f)

This function is only used for debugging. It will dump as much of the state of the running system as possible.

void dns_adb_dumpfind (dns_adbfind_t *find, FILE *f)

This function is only used for debugging. Dump the data associated with a find.

isc_result_t dns_adb_marklame (dns_adb_t *adb, dns_adbaddrinfo_t *addr, dns_name_t *qname, dns_rdatatype_t type, isc_stdtime_t expire_time)

Mark the given address as lame for the <qname,qtype>. expire_time should be set to the time when the entry should expire. That is, if it is to expire 10 minutes in the future, it should set it to (now + 10 * 60).

void dns_adb_adjustsrtt (dns_adb_t *adb, dns_adbaddrinfo_t *addr, unsigned int rtt, unsigned int factor)

Mix the round trip time into the existing smoothed rtt.

void dns_adb_agesrtt (dns_adb_t *adb, dns_adbaddrinfo_t *addr, isc_stdtime_t now)

void dns_adb_changeflags (dns_adb_t *adb, dns_adbaddrinfo_t *addr, unsigned int bits, unsigned int mask)

void dns_adb_setudpsize (dns_adb_t *adb, dns_adbaddrinfo_t *addr, unsigned int size)

Change Flags.

unsigned int dns_adb_getudpsize (dns_adb_t *adb, dns_adbaddrinfo_t *addr)

Update seen UDP response size. The largest seen will be returned by dns_adb_getudpsize().

unsigned int dns_adb_probesize (dns_adb_t *adb, dns_adbaddrinfo_t *addr)

Return the largest seen UDP response size.

unsigned int dns_adb_probesize2 (dns_adb_t *adb, dns_adbaddrinfo_t *addr, int lookups)

void dns_adb_plainresponse (dns_adb_t *adb, dns_adbaddrinfo_t *addr)

Return suggested EDNS UDP size based on observed responses / failures. 'lookups' is the number of times the current lookup has been attempted.

void dns_adb_timeout (dns_adb_t *adb, dns_adbaddrinfo_t *addr)

Record a successful plain DNS response.

void dns_adb_ednsto (dns_adb_t *adb, dns_adbaddrinfo_t *addr, unsigned int size)

Record a plain DNS UDP query failed.

isc_boolean_t dns_adb_noedns (dns_adb_t *adb, dns_adbaddrinfo_t *addr)

Record a failed EDNS UDP response and the advertised EDNS UDP buffer size used.

isc_result_t dns_adb_findaddrinfo (dns_adb_t *adb, isc_sockaddr_t *sa, dns_adbaddrinfo_t **addrp, isc_stdtime_t now)

Return whether EDNS should be disabled for this server.

void dns_adb_freeaddrinfo (dns_adb_t *adb, dns_adbaddrinfo_t **addrp)

Free a dns_adbaddrinfo_t allocated by dns_adb_findaddrinfo().

void dns_adb_flush (dns_adb_t *adb)

Flushes all cached data from the adb.

void dns_adb_setadbsize (dns_adb_t *adb, size_t size)

Set a target memory size. If memory usage exceeds the target size entries will be removed before they would have expired on a random basis.

void dns_adb_flushname (dns_adb_t *adb, dns_name_t *name)

Flush 'name' from the adb cache.

void dns_adb_flushnames (dns_adb_t *adb, dns_name_t *name)

Flush 'name' and all subdomains from the adb cache.

void dns_adb_setsit (dns_adb_t *adb, dns_adbaddrinfo_t *addr, const unsigned char *sit, size_t len)

Record the Source Identity Token (SIT) associated with this addresss. If sit is NULL or len is zero. The recorded SIT is cleared.

size_t dns_adb_getsit (dns_adb_t *adb, dns_adbaddrinfo_t *addr, unsigned char *sit, size_t len)

Detailed Description

DNS Address Database.

This module implements an address database (ADB) for mapping a name to an isc_sockaddr_t. It also provides statistical information on how good that address might be.

A client will pass in a dns_name_t, and the ADB will walk through the rdataset looking up addresses associated with the name. If it is found on the internal lists, a structure is filled in with the address information and stats for found addresses.

If the name cannot be found on the internal lists, a new entry will be created for a name if all the information needed can be found in the zone table or cache. This new address will then be returned.

If a request must be made to remote servers to satisfy a name lookup, this module will start fetches to try to complete these addresses. When at least one more completes, an event is sent to the caller. If none of them resolve before the fetch times out, an event indicating this is sent instead.

Records are stored internally until a timer expires. The timer is the smaller of the TTL or signature validity period.

Lameness is stored per <qname,qtype> tuple, and this data hangs off each address field. When an address is marked lame for a given tuple the address will not be returned to a caller.

MP:

The ADB takes care of all necessary locking.

Only the task which initiated the name lookup can cancel the lookup.

Security:

None, since all data stored is required to be pre-filtered. (Cache needs to be sane, fetches return bounds-checked and sanity- checked data, caller passes a good dns_name_t for the zone, etc)

Definition in file adb.h.

Define Documentation

#define DNS_ADB_H 1

Definition at line 21 of file adb.h.

#define DNS_ADBFIND_MAGIC ISC_MAGIC('a','d','b','H')

Definition at line 90 of file adb.h.

Referenced by new_adbfind().

#define DNS_ADBFIND_VALID ( x ) ISC_MAGIC_VALID(x, DNS_ADBFIND_MAGIC)

Definition at line 91 of file adb.h.

Referenced by dns_adb_destroyfind(), event_free(), and free_adbfind().

#define DNS_ADBADDRINFO_MAGIC ISC_MAGIC('a','d','A','I')

Definition at line 92 of file adb.h.

Referenced by new_adbaddrinfo().

#define DNS_ADBADDRINFO_VALID ( x ) ISC_MAGIC_VALID(x, DNS_ADBADDRINFO_MAGIC)

Definition at line 93 of file adb.h.

Referenced by dns_adb_adjustsrtt(), dns_adb_agesrtt(), dns_adb_changeflags(), dns_adb_ednsto(), dns_adb_freeaddrinfo(), dns_adb_getsit(), dns_adb_getudpsize(), dns_adb_marklame(), dns_adb_noedns(), dns_adb_plainresponse(), dns_adb_probesize2(), dns_adb_setsit(), dns_adb_setudpsize(), dns_adb_timeout(), and free_adbaddrinfo().

#define DNS_ADBFIND_INET 0x00000001

Return addresses of type INET.

Definition at line 166 of file adb.h.

Referenced by check_expire_namehooks(), copy_namehook_lists(), dns_adb_createfind2(), fctx_getaddresses(), fetch_callback(), generate_reply(), import_rdataset(), notify_find_address(), restart_find(), and setup_addresses().

#define DNS_ADBFIND_INET6 0x00000002

Return addresses of type INET6.

Definition at line 168 of file adb.h.

#define DNS_ADBFIND_ADDRESSMASK 0x00000003

Definition at line 169 of file adb.h.

Referenced by clean_finds_at_name(), dns_adb_createfind2(), fctx_getaddresses(), and kill_name().

#define DNS_ADBFIND_EMPTYEVENT 0x00000004

Only schedule an event if no addresses are known. Must set _WANTEVENT for this to be meaningful.

Definition at line 174 of file adb.h.

Referenced by fctx_getaddresses().

#define DNS_ADBFIND_WANTEVENT 0x00000008

An event is desired. Check this bit in the returned find to see if one will actually be generated.

Definition at line 179 of file adb.h.

Referenced by dns_adb_createfind2(), fctx_getaddresses(), findname(), notify_find_address(), and restart_find().

#define DNS_ADBFIND_AVOIDFETCHES 0x00000010

If set, fetches will not be generated unless no addresses are available in any of the address families requested.

Definition at line 184 of file adb.h.

Referenced by fctx_getaddresses().

#define DNS_ADBFIND_STARTATZONE 0x00000020

Fetches will start using the closest zone data or use the root servers. This is useful for reestablishing glue that has expired.

Definition at line 189 of file adb.h.

Referenced by findname().

#define DNS_ADBFIND_GLUEOK 0x00000040

Glue or hints are ok. These are used when matching names already in the adb, and when dns databases are searched.

Definition at line 194 of file adb.h.

Referenced by dbfind_name(), and findname().

#define DNS_ADBFIND_HINTOK 0x00000080

Glue or hints are ok. These are used when matching names already in the adb, and when dns databases are searched.

Definition at line 199 of file adb.h.

Referenced by dbfind_name(), and findname().

#define DNS_ADBFIND_RETURNLAME 0x00000100

Return lame servers in a find, so that all addresses are returned.

Definition at line 203 of file adb.h.

Referenced by notify_find_address(), and restart_find().

#define DNS_ADBFIND_LAMEPRUNED 0x00000200

Only schedule an event if no addresses are known. Must set _WANTEVENT for this to be meaningful.

Definition at line 208 of file adb.h.

Referenced by copy_namehook_lists(), and findname().

#define DNS_ADB_RTTADJDEFAULT 7

default scale

Definition at line 529 of file adb.h.

Referenced by fctx_cancelquery().

#define DNS_ADB_RTTADJREPLACE 0

replace with our rtt

Definition at line 530 of file adb.h.

Referenced by fctx_cancelquery().

#define DNS_ADB_RTTADJAGE 10

age this rtt

Definition at line 531 of file adb.h.

Referenced by adjustsrtt(), dns_adb_adjustsrtt(), and dns_adb_agesrtt().

Typedef Documentation

typedef struct dns_adbname dns_adbname_t

Definition at line 100 of file adb.h.

Function Documentation

isc_result_t dns_adb_create	(	isc_mem_t *	mem,
		dns_view_t *	view,
		isc_timermgr_t *	tmgr,
		isc_taskmgr_t *	taskmgr,
		dns_adb_t **	newadb
	)

Create a new ADB.

Notes:

Generally, applications should not create an ADB directly, but should instead call dns_view_createresolver().

Requires:

'mem' must be a valid memory context.

'view' be a pointer to a valid view.

'tmgr' be a pointer to a valid timer manager.

'taskmgr' be a pointer to a valid task manager.

'newadb' != NULL && '*newadb' == NULL.

Returns:

ISC_R_SUCCESS after happiness.
ISC_R_NOMEMORY after resource allocation failure.

Definition at line 2461 of file adb.c.

References dns_adbname::adb, dns_view::adbstats, ALLOCENTRY, ALLOCNAME, DEF_LEVEL, DESTROYLOCK, DESTROYMUTEXBLOCK, DNS_ADB_MAGIC, dns_adbstats_max, dns_adbstats_nentries, dns_adbstats_nnames, DNS_EVENT_ADBGROWENTRIES, DNS_EVENT_ADBGROWNAMES, DP(), grow_entries(), grow_names(), ISC_EVENT_INIT, ISC_FALSE, ISC_LIST_INIT, isc_mem_attach(), isc_mem_get, isc_mem_put, isc_mem_putanddetach, isc_mempool_destroy(), isc_mutex_init, isc_mutexblock_init(), ISC_R_NOMEMORY, ISC_R_SUCCESS, isc_stats_create(), isc_task_create(), isc_task_detach(), isc_task_setname(), isc_taskmgr_excltask(), MPINIT, REQUIRE, set_adbstat(), and UNUSED.

Referenced by dns_view_createresolver().

void dns_adb_attach	(	dns_adb_t *	adb,
		dns_adb_t **	adbp
	)

Definition at line 2744 of file adb.c.

References DNS_ADB_VALID, inc_adb_erefcnt(), and REQUIRE.

Referenced by fctx_create().

void dns_adb_detach ( dns_adb_t ** adb )

Attach to an 'adb' to 'adbp'.

Requires:

'adb' to be a valid dns_adb_t, created via dns_adb_create().
'adbp' to be a valid pointer to a *dns_adb_t which is initialized to NULL.

Definition at line 2754 of file adb.c.

References dns_adbname::adb, check_exit(), DNS_ADB_VALID, INSIST, ISC_TF, LOCK, REQUIRE, and UNLOCK.

Referenced by destroy(), and fctx_destroy().

void dns_adb_whenshutdown	(	dns_adb_t *	adb,
		isc_task_t *	task,
		isc_event_t **	eventp
	)

Delete the ADB. Sets *ADB to NULL. Cancels any outstanding requests.

Requires:

'adb' be non-NULL and '*adb' be a valid dns_adb_t, created via dns_adb_create().

Definition at line 2779 of file adb.c.

References DNS_ADB_VALID, ISC_FALSE, ISC_LIST_APPEND, isc_mempool_getallocated(), isc_task_attach(), isc_task_send(), ISC_TF, LOCK, REQUIRE, and UNLOCK.

Referenced by dns_view_createresolver().

void dns_adb_shutdown ( dns_adb_t * adb )

Send '*eventp' to 'task' when 'adb' has shutdown.

Requires:

'*adb' is a valid dns_adb_t.

eventp != NULL && *eventp is a valid event.

Ensures:

*eventp == NULL

The event's sender field is set to the value of adb when the event is sent. Shutdown 'adb'.

Requires:

'*adb' is a valid dns_adb_t.

Definition at line 2837 of file adb.c.

References DNS_EVENT_ADBCONTROL, inc_adb_irefcnt(), ISC_EVENT_INIT, isc_mem_setwater(), isc_task_send(), ISC_TRUE, LOCK, shutdown_stage2(), UNLOCK, and water().

Referenced by dns_view_createresolver(), and view_flushanddetach().

isc_result_t dns_adb_createfind	(	dns_adb_t *	adb,
		isc_task_t *	task,
		isc_taskaction_t	action,
		void *	arg,
		dns_name_t *	name,
		dns_name_t *	qname,
		dns_rdatatype_t	qtype,
		unsigned int	options,
		isc_stdtime_t	now,
		dns_name_t *	target,
		in_port_t	port,
		dns_adbfind_t **	find
	)

Definition at line 2865 of file adb.c.

References dns_adb_createfind2().

Referenced by notify_find_address(), and restart_find().

isc_result_t dns_adb_createfind2	(	dns_adb_t *	adb,
		isc_task_t *	task,
		isc_taskaction_t	action,
		void *	arg,
		dns_name_t *	name,
		dns_name_t *	qname,
		dns_rdatatype_t	qtype,
		unsigned int	options,
		isc_stdtime_t	now,
		dns_name_t *	target,
		in_port_t	port,
		unsigned int	depth,
		isc_counter_t *	qc,
		dns_adbfind_t **	find
	)

Main interface for clients. The adb will look up the name given in "name" and will build up a list of found addresses, and perhaps start internal fetches to resolve names that are unknown currently.

If other addresses resolve after this call completes, an event will be sent to the <task, taskaction, arg> with the sender of that event set to a pointer to the dns_adbfind_t returned by this function.

If no events will be generated, the *find->result_v4 and/or result_v6 members may be examined for address lookup status. The usual ISC_R_SUCCESS, ISC_R_FAILURE, DNS_R_NXDOMAIN, and DNS_R_NXRRSET are returned, along with ISC_R_NOTFOUND meaning the ADB has not _yet_ found the values. In this latter case, retrying may produce more addresses.

If events will be returned, the result_v[46] members are only valid when that event is actually returned.

The list of addresses returned is unordered. The caller must impose any ordering required. The list will not contain "known bad" addresses, however. For instance, it will not return hosts that are known to be lame for the zone in question.

The caller cannot (directly) modify the contents of the address list's fields other than the "link" field. All values can be read at any time, however.

The "now" parameter is used only for determining which entries that have a specific time to live or expire time should be removed from the running database. If specified as zero, the current time will be retrieved and used.

If 'target' is not NULL and 'name' is an alias (i.e. the name is CNAME'd or DNAME'd to another name), then 'target' will be updated with the domain name that 'name' is aliased to.

All addresses returned will have the sockaddr's port set to 'port.' The caller may change them directly in the dns_adbaddrinfo_t since they are copies of the internal address only.

XXXMLG Document options, especially the flags which control how events are sent.

Requires:

*adb be a valid isc_adb_t object.

If events are to be sent, *task be a valid task, and isc_taskaction_t != NULL.

*name is a valid dns_name_t.

qname != NULL and *qname be a valid dns_name_t.

target == NULL or target is a valid name with a buffer.

find != NULL && *find == NULL.

Returns:

ISC_R_SUCCESS Addresses might have been returned, and events will be delivered for unresolved addresses.
ISC_R_NOMORE Addresses might have been returned, but no events will ever be posted for this context. This is only returned if task != NULL.
ISC_R_NOMEMORY insufficient resources
DNS_R_ALIAS 'name' is an alias for another name.

Calls, and returns error codes from:

isc_stdtime_get()

Notes:

No internal reference to "name" exists after this function returns.

Definition at line 2877 of file adb.c.

References dns_adbfind::adbname, AUTH_NX, check_expire_namehooks(), check_stale_name(), copy_namehook_lists(), dbfind_name(), DEF_LEVEL, DNS_ADB_INVALIDBUCKET, DNS_ADB_VALID, DNS_ADBFIND_ADDRESSMASK, DNS_ADBFIND_INET, DNS_ADBFIND_INET6, DNS_ADBFIND_WANTEVENT, dns_lctx, dns_name_copy(), dns_name_format(), DNS_NAME_FORMATSIZE, dns_name_hasbuffer(), DNS_R_ALIAS, DP(), dns_adbfind::event, EXPIRE_OK, dns_adbname::expire_target, dns_adbname::expire_v4, dns_adbname::expire_v6, dns_adbname::fetch6_err, dns_adbname::fetch_err, fetch_name(), find(), FIND_AVOIDFETCHES, FIND_EVENT_FREED, FIND_EVENT_SENT, FIND_GLUEOK, FIND_HAS_ADDRS, FIND_HINTOK, find_name_and_lock(), FIND_STARTATZONE, FIND_WANTEMPTYEVENT, FIND_WANTEVENT, dns_adbname::finds, dns_adbname::flags, dns_adbfind::flags, free_adbfind(), INSIST, ISC_FALSE, ISC_LIST_APPEND, ISC_LIST_PREPEND, ISC_LIST_UNLINK, isc_log_wouldlog(), ISC_R_NOMEMORY, ISC_R_SHUTTINGDOWN, ISC_R_SUCCESS, ISC_R_UNEXPECTED, isc_stdtime_get(), isc_task_attach(), ISC_TRUE, dns_adbname::last_used, link_name(), dns_adbfind::name_bucket, NAME_FETCH_V4, NAME_FETCH_V6, NAME_GLUE_OK, NAME_HAS_V4, NAME_HAS_V6, NAME_HINT_OK, NAME_STARTATZONE, namebuf, NCACHE_RESULT, new_adbfind(), new_adbname(), NXDOMAIN_RESULT, NXRRSET_RESULT, dns_adbfind::options, dns_adbname::partial_result, dns_adbfind::partial_result, dns_adbfind::port, POST, dns_adbfind::query_pending, REQUIRE, dns_adbfind::result_v4, dns_adbfind::result_v6, RUNTIME_CHECK, dns_adbname::target, UNLOCK, dns_adbname::v6, WANT_INET, and WANT_INET6.

Referenced by dns_adb_createfind(), and findname().

void dns_adb_cancelfind ( dns_adbfind_t * find )

Cancels the find, and sends the event off to the caller.

It is an error to call dns_adb_cancelfind() on a find where no event is wanted, or will ever be sent.

Note:

It is possible that the real completion event was posted just before the dns_adb_cancelfind() call was made. In this case, dns_adb_cancelfind() will do nothing. The event callback needs to be prepared to find this situation (i.e. result is valid but the caller expects it to be canceled).

Requires:

'find' be a valid dns_adbfind_t pointer.

events would have been posted to the task. This can be checked with (find->options & DNS_ADBFIND_WANTEVENT).

Ensures:

The event was posted to the task.

Definition at line 3283 of file adb.c.

References dns_adbfind::adb, dns_adbname::adb, dns_adbfind::adbname, cleanup(), DEF_LEVEL, DNS_ADB_INVALIDBUCKET, DNS_ADB_VALID, DNS_EVENT_ADBCANCELED, DP(), dns_adbfind::event, event_free(), FIND_EVENTFREED, FIND_EVENTSENT, FIND_WANTEVENT, dns_adbname::finds, ISC_LIST_UNLINK, ISC_R_CANCELED, isc_task_sendanddetach(), dns_adbfind::lock, LOCK, dns_adbfind::name_bucket, POST, REQUIRE, dns_adbfind::result_v4, dns_adbfind::result_v6, UNLOCK, and violate_locking_hierarchy().

Referenced by lwdclientmgr_shutdown_callback(), and notify_cancel().

void dns_adb_destroyfind ( dns_adbfind_t ** find )

Destroys the find reference.

Note:

This can only be called after the event was delivered for a find. Additionally, the event MUST have been freed via isc_event_free() BEFORE this function is called.

Requires:

'find' != NULL and *find be valid dns_adbfind_t pointer.

Ensures:

No "address found" events will be posted to the originating task after this function returns.

Definition at line 3225 of file adb.c.

References dns_adbfind::adb, dns_adbname::adb, check_exit(), dec_entry_refcnt(), DEF_LEVEL, DNS_ADB_INVALIDBUCKET, DNS_ADB_VALID, DNS_ADBENTRY_VALID, DNS_ADBFIND_VALID, DP(), dns_adbaddrinfo::entry, find(), FIND_EVENTFREED, free_adbaddrinfo(), free_adbfind(), INSIST, ISC_FALSE, ISC_LIST_HEAD, ISC_LIST_UNLINK, isc_mem_isovermem(), ISC_TRUE, dns_adbfind::list, dns_adbfind::lock, LOCK, dns_adbfind::name_bucket, overmem(), REQUIRE, RUNTIME_CHECK, and UNLOCK.

Referenced by cleanup_gabn(), fctx_cleanupaltfinds(), fctx_cleanupfinds(), fctx_finddone(), findname(), generate_reply(), notify_destroy(), process_adb_event(), process_gabn_finddone(), and restart_find().

void dns_adb_dump	(	dns_adb_t *	adb,
		FILE *	f
	)

This function is only used for debugging. It will dump as much of the state of the running system as possible.

Requires:

adb be valid.

f != NULL, and is a file open for writing.

Definition at line 3341 of file adb.c.

References cleanup_entries(), cleanup_names(), DNS_ADB_VALID, dump_adb(), ISC_FALSE, isc_stdtime_get(), LOCK, REQUIRE, RUNTIME_CHECK, and UNLOCK.

Referenced by dns_view_dumpdbtostream(), and dumpdone().

void dns_adb_dumpfind	(	dns_adbfind_t *	find,
		FILE *	f
	)

This function is only used for debugging. Dump the data associated with a find.

Requires:

find is valid.

f != NULL, and is a file open for writing.

Definition at line 3505 of file adb.c.

References dns_adbfind::adbname, AF_INET6, dns_adbaddrinfo::entry, dns_adbfind::event, dns_adbaddrinfo::flags, dns_adbfind::flags, ISC_LIST_HEAD, ISC_LIST_NEXT, dns_adbfind::list, dns_adbfind::lock, LOCK, dns_adbfind::name_bucket, dns_adbfind::options, dns_adbfind::partial_result, dns_adbfind::query_pending, isc_sockaddr::sa, isc_sockaddr::sin, isc_sockaddr::sin6, sockaddr_in6::sin6_addr, dns_adbaddrinfo::sockaddr, dns_adbaddrinfo::srtt, isc_sockaddr::type, and UNLOCK.

Referenced by print_find_list().

isc_result_t dns_adb_marklame	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		dns_name_t *	qname,
		dns_rdatatype_t	type,
		isc_stdtime_t	expire_time
	)

Mark the given address as lame for the <qname,qtype>. expire_time should be set to the time when the entry should expire. That is, if it is to expire 10 minutes in the future, it should set it to (now + 10 * 60).

Requires:

adb be valid.

addr be valid.

qname be the qname used in the dns_adb_createfind() call.

Returns:

ISC_R_SUCCESS -- all is well.
ISC_R_NOMEMORY -- could not mark address as lame.

Definition at line 4013 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_name_equal(), dns_adbaddrinfo::entry, ISC_LIST_HEAD, ISC_LIST_NEXT, ISC_LIST_PREPEND, ISC_R_NOMEMORY, ISC_R_SUCCESS, LOCK, dns_adbentry::lock_bucket, new_adblameinfo(), REQUIRE, and UNLOCK.

Referenced by resquery_response().

void dns_adb_adjustsrtt	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		unsigned int	rtt,
		unsigned int	factor
	)

Mix the round trip time into the existing smoothed rtt.

Requires:

adb be valid.

addr be valid.

0 <= factor <= 10

Note:

The srtt in addr will be updated to reflect the new global srtt value. This may include changes made by others.

Definition at line 4051 of file adb.c.

References adjustsrtt(), DNS_ADB_RTTADJAGE, DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbaddrinfo::entry, dns_adbentry::expires, isc_stdtime_get(), LOCK, dns_adbentry::lock_bucket, REQUIRE, and UNLOCK.

Referenced by fctx_cancelquery().

void dns_adb_agesrtt	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		isc_stdtime_t	now
	)

Definition at line 4072 of file adb.c.

References adjustsrtt(), DNS_ADB_RTTADJAGE, DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbaddrinfo::entry, LOCK, dns_adbentry::lock_bucket, REQUIRE, and UNLOCK.

Referenced by fctx_cancelquery().

void dns_adb_changeflags	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		unsigned int	bits,
		unsigned int	mask
	)

Definition at line 4113 of file adb.c.

References ADB_ENTRY_WINDOW, DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbaddrinfo::entry, ENTRY_IS_DEAD, dns_adbentry::expires, dns_adbaddrinfo::flags, dns_adbentry::flags, isc_stdtime_get(), LOCK, dns_adbentry::lock_bucket, REQUIRE, and UNLOCK.

Referenced by fctx_cancelquery(), resquery_response(), and resquery_send().

void dns_adb_setudpsize	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		unsigned int	size
	)

Change Flags.

Set the flags as given by:

newflags = (oldflags & ~mask) | (bits & mask);

Requires:

adb be valid.

addr be valid.

Definition at line 4280 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbentry::edns, dns_adbaddrinfo::entry, LOCK, dns_adbentry::lock_bucket, dns_adbentry::plain, dns_adbentry::plainto, REQUIRE, dns_adbentry::to1232, dns_adbentry::to1432, dns_adbentry::to4096, dns_adbentry::to512, dns_adbentry::udpsize, and UNLOCK.

Referenced by resquery_response().

unsigned int dns_adb_getudpsize	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr
	)

Update seen UDP response size. The largest seen will be returned by dns_adb_getudpsize().

Requires:

adb be valid.

addr be valid.

Definition at line 4306 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbaddrinfo::entry, LOCK, dns_adbentry::lock_bucket, REQUIRE, dns_adbentry::udpsize, and UNLOCK.

Referenced by resquery_send().

unsigned int dns_adb_probesize	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr
	)

Return the largest seen UDP response size.

Requires:

adb be valid.

addr be valid.

Definition at line 4322 of file adb.c.

References dns_adb_probesize2().

unsigned int dns_adb_probesize2	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		int	lookups
	)

Definition at line 4327 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, EDNSTOS, dns_adbaddrinfo::entry, LOCK, dns_adbentry::lock_bucket, REQUIRE, dns_adbentry::to1232, dns_adbentry::to1432, dns_adbentry::to4096, dns_adbentry::udpsize, and UNLOCK.

Referenced by dns_adb_probesize(), and resquery_send().

void dns_adb_plainresponse	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr
	)

Return suggested EDNS UDP size based on observed responses / failures. 'lookups' is the number of times the current lookup has been attempted.

Requires:

adb be valid.

addr be valid.

Definition at line 4179 of file adb.c.

Referenced by resquery_response().

void dns_adb_timeout	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr
	)

Record a successful plain DNS response.

Requires:

adb be valid.

addr be valid.

Definition at line 4202 of file adb.c.

Referenced by fctx_cancelquery().

void dns_adb_ednsto	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		unsigned int	size
	)

Record a plain DNS UDP query failed.

Requires:

adb be valid.

addr be valid.

Definition at line 4235 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbentry::edns, EDNSTOS, dns_adbaddrinfo::entry, LOCK, dns_adbentry::lock_bucket, dns_adbentry::plain, dns_adbentry::plainto, REQUIRE, dns_adbentry::to1232, dns_adbentry::to1432, dns_adbentry::to4096, dns_adbentry::to512, and UNLOCK.

Referenced by fctx_cancelquery().

isc_boolean_t dns_adb_noedns	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr
	)

Record a failed EDNS UDP response and the advertised EDNS UDP buffer size used.

Requires:

adb be valid.

addr be valid.

Definition at line 4145 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbentry::edns, EDNSTOS, dns_adbaddrinfo::entry, ISC_FALSE, ISC_TRUE, LOCK, dns_adbentry::lock_bucket, dns_adbentry::plain, dns_adbentry::plainto, REQUIRE, dns_adbentry::to1232, dns_adbentry::to1432, dns_adbentry::to4096, dns_adbentry::to512, and UNLOCK.

Referenced by resquery_send().

isc_result_t dns_adb_findaddrinfo	(	dns_adb_t *	adb,
		isc_sockaddr_t *	sa,
		dns_adbaddrinfo_t **	addrp,
		isc_stdtime_t	now
	)

Return whether EDNS should be disabled for this server.

Requires:

adb be valid.

addr be valid. Return a dns_adbaddrinfo_t that is associated with address 'sa'.

Requires:

adb is valid.

sa is valid.

addrp != NULL && *addrp == NULL

Returns:

Definition at line 4410 of file adb.c.

References DNS_ADB_INVALIDBUCKET, DNS_ADB_VALID, DP(), ENTER_LEVEL, find_entry_and_lock(), inc_entry_refcnt(), INSIST, ISC_FALSE, ISC_R_NOMEMORY, ISC_R_SHUTTINGDOWN, ISC_R_SUCCESS, isc_sockaddr_getport(), link_entry(), new_adbaddrinfo(), new_adbentry(), port, REQUIRE, dns_adbentry::sockaddr, UNLOCK, and UNUSED.

Referenced by fctx_getaddresses().

void dns_adb_freeaddrinfo	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t **	addrp
	)

Free a dns_adbaddrinfo_t allocated by dns_adb_findaddrinfo().

Requires:

adb is valid.

*addrp is a valid dns_adbaddrinfo_t *.

Definition at line 4463 of file adb.c.

References ADB_ENTRY_WINDOW, check_exit(), dec_entry_refcnt(), DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, DNS_ADBENTRY_VALID, dns_adbaddrinfo::entry, dns_adbentry::expires, free_adbaddrinfo(), ISC_FALSE, isc_mem_isovermem(), isc_stdtime_get(), LOCK, dns_adbentry::lock_bucket, overmem(), REQUIRE, and UNLOCK.

Referenced by fctx_cleanupaltaddrs(), and fctx_cleanupforwaddrs().

void dns_adb_flush ( dns_adb_t * adb )

Flushes all cached data from the adb.

Requires:

adb is valid.

Definition at line 4504 of file adb.c.

References cleanup_entries(), cleanup_names(), DNS_ADB_VALID, dump_adb(), INSIST, ISC_FALSE, ISC_TRUE, LOCK, RUNTIME_CHECK, and UNLOCK.

Referenced by dns_view_flushcache2().

void dns_adb_setadbsize	(	dns_adb_t *	adb,
		size_t	size
	)

Set a target memory size. If memory usage exceeds the target size entries will be removed before they would have expired on a random basis.

If 'size' is 0 then memory usage is unlimited.

Requires:

'adb' is valid.

Definition at line 4602 of file adb.c.

References DNS_ADB_MINADBSIZE, DNS_ADB_VALID, INSIST, isc_mem_setwater(), and water().

Referenced by configure_view().

void dns_adb_flushname	(	dns_adb_t *	adb,
		dns_name_t *	name
	)

Flush 'name' from the adb cache.

Requires:

'adb' is valid.
'name' is valid.

Definition at line 4527 of file adb.c.

References DNS_ADB_VALID, DNS_EVENT_ADBCANCELED, dns_name_equal(), dns_name_hash(), ISC_FALSE, ISC_LIST_HEAD, ISC_LIST_NEXT, kill_name(), LOCK, dns_adbname::name, NAME_DEAD, REQUIRE, RUNTIME_CHECK, and UNLOCK.

Referenced by dns_view_flushnode().

void dns_adb_flushnames	(	dns_adb_t *	adb,
		dns_name_t *	name
	)

Flush 'name' and all subdomains from the adb cache.

Requires:

'adb' is valid.
'name' is valid.

Definition at line 4554 of file adb.c.

References DNS_ADB_VALID, DNS_EVENT_ADBCANCELED, dns_name_issubdomain(), ISC_FALSE, ISC_LIST_HEAD, ISC_LIST_NEXT, kill_name(), LOCK, dns_adbname::name, NAME_DEAD, REQUIRE, RUNTIME_CHECK, and UNLOCK.

Referenced by dns_view_flushnode().

void dns_adb_setsit	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		const unsigned char *	sit,
		size_t	len
	)

Record the Source Identity Token (SIT) associated with this addresss. If sit is NULL or len is zero. The recorded SIT is cleared.

Requires:

'adb' is valid.
'addr' is valid.

Definition at line 4357 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbaddrinfo::entry, isc_mem_get, isc_mem_put, LOCK, dns_adbentry::lock_bucket, REQUIRE, dns_adbentry::sit, dns_adbentry::sitlen, and UNLOCK.

Referenced by process_opt().

size_t dns_adb_getsit	(	dns_adb_t *	adb,
		dns_adbaddrinfo_t *	addr,
		unsigned char *	sit,
		size_t	len
	)

Definition at line 4387 of file adb.c.

References DNS_ADB_VALID, DNS_ADBADDRINFO_VALID, dns_adbaddrinfo::entry, LOCK, dns_adbentry::lock_bucket, REQUIRE, dns_adbentry::sit, dns_adbentry::sitlen, and UNLOCK.

Referenced by resquery_response(), and resquery_send().

Generated on Tue Apr 28 17:41:08 2015 by Doxygen 1.5.4 for BIND9 Internals 9.11.0pre-alpha


Data Structures
struct	dns_adbfind
	Represents a lookup for a single name. More...
struct	dns_adbaddrinfo
	The answers to queries come back as a list of these. More...
Defines
#define	DNS_ADB_H 1
#define	DNS_ADBFIND_MAGIC ISC_MAGIC('a','d','b','H')
#define	DNS_ADBFIND_VALID(x) ISC_MAGIC_VALID(x, DNS_ADBFIND_MAGIC)
#define	DNS_ADBADDRINFO_MAGIC ISC_MAGIC('a','d','A','I')
#define	DNS_ADBADDRINFO_VALID(x) ISC_MAGIC_VALID(x, DNS_ADBADDRINFO_MAGIC)
#define	DNS_ADBFIND_INET 0x00000001
	Return addresses of type INET.
#define	DNS_ADBFIND_INET6 0x00000002
	Return addresses of type INET6.
#define	DNS_ADBFIND_ADDRESSMASK 0x00000003
#define	DNS_ADBFIND_EMPTYEVENT 0x00000004
	Only schedule an event if no addresses are known. Must set _WANTEVENT for this to be meaningful.
#define	DNS_ADBFIND_WANTEVENT 0x00000008
	An event is desired. Check this bit in the returned find to see if one will actually be generated.
#define	DNS_ADBFIND_AVOIDFETCHES 0x00000010
	If set, fetches will not be generated unless no addresses are available in any of the address families requested.
#define	DNS_ADBFIND_STARTATZONE 0x00000020
	Fetches will start using the closest zone data or use the root servers. This is useful for reestablishing glue that has expired.
#define	DNS_ADBFIND_GLUEOK 0x00000040
	Glue or hints are ok. These are used when matching names already in the adb, and when dns databases are searched.
#define	DNS_ADBFIND_HINTOK 0x00000080
	Glue or hints are ok. These are used when matching names already in the adb, and when dns databases are searched.
#define	DNS_ADBFIND_RETURNLAME 0x00000100
	Return lame servers in a find, so that all addresses are returned.
#define	DNS_ADBFIND_LAMEPRUNED 0x00000200
	Only schedule an event if no addresses are known. Must set _WANTEVENT for this to be meaningful.
#define	DNS_ADB_RTTADJDEFAULT 7
	default scale
#define	DNS_ADB_RTTADJREPLACE 0
	replace with our rtt
#define	DNS_ADB_RTTADJAGE 10
	age this rtt
Typedefs
typedef struct dns_adbname	dns_adbname_t
Functions
isc_result_t	dns_adb_create (isc_mem_t mem, dns_view_t view, isc_timermgr_t tmgr, isc_taskmgr_t taskmgr, dns_adb_t **newadb)
	Create a new ADB.
void	dns_adb_attach (dns_adb_t adb, dns_adb_t *adbp)
void	dns_adb_detach (dns_adb_t **adb)
	Attach to an 'adb' to 'adbp'.
void	dns_adb_whenshutdown (dns_adb_t adb, isc_task_t task, isc_event_t **eventp)
	Delete the ADB. Sets *ADB to NULL. Cancels any outstanding requests.
void	dns_adb_shutdown (dns_adb_t *adb)
	Send '*eventp' to 'task' when 'adb' has shutdown.
isc_result_t	dns_adb_createfind (dns_adb_t adb, isc_task_t task, isc_taskaction_t action, void arg, dns_name_t name, dns_name_t qname, dns_rdatatype_t qtype, unsigned int options, isc_stdtime_t now, dns_name_t target, in_port_t port, dns_adbfind_t **find)
isc_result_t	dns_adb_createfind2 (dns_adb_t adb, isc_task_t task, isc_taskaction_t action, void arg, dns_name_t name, dns_name_t qname, dns_rdatatype_t qtype, unsigned int options, isc_stdtime_t now, dns_name_t target, in_port_t port, unsigned int depth, isc_counter_t qc, dns_adbfind_t *find)
	Main interface for clients. The adb will look up the name given in "name" and will build up a list of found addresses, and perhaps start internal fetches to resolve names that are unknown currently.
void	dns_adb_cancelfind (dns_adbfind_t *find)
	Cancels the find, and sends the event off to the caller.
void	dns_adb_destroyfind (dns_adbfind_t **find)
	Destroys the find reference.
void	dns_adb_dump (dns_adb_t adb, FILE f)
	This function is only used for debugging. It will dump as much of the state of the running system as possible.
void	dns_adb_dumpfind (dns_adbfind_t find, FILE f)
	This function is only used for debugging. Dump the data associated with a find.
isc_result_t	dns_adb_marklame (dns_adb_t adb, dns_adbaddrinfo_t addr, dns_name_t *qname, dns_rdatatype_t type, isc_stdtime_t expire_time)
	Mark the given address as lame for the <qname,qtype>. expire_time should be set to the time when the entry should expire. That is, if it is to expire 10 minutes in the future, it should set it to (now + 10 * 60).
void	dns_adb_adjustsrtt (dns_adb_t adb, dns_adbaddrinfo_t addr, unsigned int rtt, unsigned int factor)
	Mix the round trip time into the existing smoothed rtt.
void	dns_adb_agesrtt (dns_adb_t adb, dns_adbaddrinfo_t addr, isc_stdtime_t now)
void	dns_adb_changeflags (dns_adb_t adb, dns_adbaddrinfo_t addr, unsigned int bits, unsigned int mask)
void	dns_adb_setudpsize (dns_adb_t adb, dns_adbaddrinfo_t addr, unsigned int size)
	Change Flags.
unsigned int	dns_adb_getudpsize (dns_adb_t adb, dns_adbaddrinfo_t addr)
	Update seen UDP response size. The largest seen will be returned by dns_adb_getudpsize().
unsigned int	dns_adb_probesize (dns_adb_t adb, dns_adbaddrinfo_t addr)
	Return the largest seen UDP response size.
unsigned int	dns_adb_probesize2 (dns_adb_t adb, dns_adbaddrinfo_t addr, int lookups)
void	dns_adb_plainresponse (dns_adb_t adb, dns_adbaddrinfo_t addr)
	Return suggested EDNS UDP size based on observed responses / failures. 'lookups' is the number of times the current lookup has been attempted.
void	dns_adb_timeout (dns_adb_t adb, dns_adbaddrinfo_t addr)
	Record a successful plain DNS response.
void	dns_adb_ednsto (dns_adb_t adb, dns_adbaddrinfo_t addr, unsigned int size)
	Record a plain DNS UDP query failed.
isc_boolean_t	dns_adb_noedns (dns_adb_t adb, dns_adbaddrinfo_t addr)
	Record a failed EDNS UDP response and the advertised EDNS UDP buffer size used.
isc_result_t	dns_adb_findaddrinfo (dns_adb_t adb, isc_sockaddr_t sa, dns_adbaddrinfo_t **addrp, isc_stdtime_t now)
	Return whether EDNS should be disabled for this server.
void	dns_adb_freeaddrinfo (dns_adb_t adb, dns_adbaddrinfo_t *addrp)
	Free a dns_adbaddrinfo_t allocated by dns_adb_findaddrinfo().
void	dns_adb_flush (dns_adb_t *adb)
	Flushes all cached data from the adb.
void	dns_adb_setadbsize (dns_adb_t *adb, size_t size)
	Set a target memory size. If memory usage exceeds the target size entries will be removed before they would have expired on a random basis.
void	dns_adb_flushname (dns_adb_t adb, dns_name_t name)
	Flush 'name' from the adb cache.
void	dns_adb_flushnames (dns_adb_t adb, dns_name_t name)
	Flush 'name' and all subdomains from the adb cache.
void	dns_adb_setsit (dns_adb_t adb, dns_adbaddrinfo_t addr, const unsigned char *sit, size_t len)
	Record the Source Identity Token (SIT) associated with this addresss. If sit is NULL or len is zero. The recorded SIT is cleared.
size_t	dns_adb_getsit (dns_adb_t adb, dns_adbaddrinfo_t addr, unsigned char *sit, size_t len)