The DNSQuestion (dq) object

Apart from the ipfilter()-function, all functions work on a dq (DNSQuestion) object. This object contains details about the current state of the question. This state can be modified from the various hooks.

The DNSQuestion object contains at least the following fields:

class DNSQuestion

An object that contains everything about the current query. This object has the following attributes:

qname

DNSName of the name this query is for.

qtype

Type this query is for as an integer, can be compared against pdns.A, pdns.AAAA.

rcode

current DNS Result Code, which can be overridden, including to several magical values The rcode can be set to pdns.DROP to drop the query. Other statuses are normal DNS return codes, like pdns.NOERROR, pdns.NXDOMAIN etc.

isTcp

Whether the query was received over TCP.

remoteaddr

ComboAddress of the requestor.

localaddr

ComboAddress where this query was received on.

variable

Boolean which, if set, indicates the recursor should not packet cache this answer. Honored even when returning false from a hook! Important when providing answers that vary over time or based on sender details.

followupFunction

String that signals the nameserver to take one an additional action:

  • followCNAMERecords: When adding a CNAME to the answer, this tells the recursor to follow that CNAME. See CNAME Chain Resolution
  • getFakeAAAARecords: Get a fake AAAA record, see DNS64
  • getFakePTRRecords: Get a fake PTR record, see DNS64
  • udpQueryResponse: Do a UDP query and call a handler, see UDP Query Response
appliedPolicy

The decision that was made by the policy engine, see Modifying Policy Decisions.

appliedPolicy.policyName

A string with the name of the policy. Set by policyName in the rpzFile() and rpzMaster() configuration items. It is advised to overwrite this when modifying the DNSQuestion.appliedPolicy.policyKind

appliedPolicy.policyAction

The action taken by the engine

appliedPolicy.policyCustom

The CNAME content for the pdns.policyactions.Custom response, a string

appliedPolicy.policyKind

The kind of policy response, there are several policy kinds:

  • pdns.policykinds.Custom will return a NoError, CNAME answer with the value specified in DNSQuestion.appliedPolicy.policyCustom
  • pdns.policykinds.Drop will simply cause the query to be dropped
  • pdns.policykinds.NoAction will continue normal processing of the query
  • pdns.policykinds.NODATA will return a NoError response with no value in the answer section
  • pdns.policykinds.NXDOMAIN will return a response with a NXDomain rcode
  • pdns.policykinds.Truncate will return a NoError, no answer, truncated response over UDP. Normal processing will continue over TCP
appliedPolicy.policyTTL

The TTL in seconds for the pdns.policyactions.Custom response

wantsRPZ

A boolean that indicates the use of the Policy Engine. Can be set to false in prerpz to disable RPZ for this query.

data

A Lua object reference that is persistent throughout the lifetime of the DNSQuestion object for a single query. It can be used to store custom data. Most scripts initialise this to an empty table early on so they can store multiple items.

requestorId

New in version 4.1.0.

A string that will be used to set the requestorId field in protobuf messages.

deviceId

New in version 4.1.0.

A string that will be used to set the deviceId field in protobuf messages.

udpAnswer

Answer to the udpQuery when when using the udpQueryResponse followupFunction. Only filled when the call-back function is invoked.

udpQueryDest

Destination IP address to send the UDP packet to when using the udpQueryResponse followupFunction

udpQuery

The content of the UDP payload when using the udpQueryResponse followupFunction

udpCallback

The name of the callback function that is called when using the udpQueryResponse followupFunction when an answer is received.

validationState

New in version 4.1.0.

The result of the DNSSEC validation, accessible from the postresolve, nxdomain and nodata hooks. Possible states are pdns.validationstates.Indeterminate, pdns.validationstates.Bogus, pdns.validationstates.Insecure and pdns.validationstates.Secure. The result will always be pdns.validationstates.Indeterminate is validation is disabled or was not requested.

logResponse

New in version 4.2.0.

Whether the response to this query will be exported to a remote protobuf logger, if one has been configured.

It also supports the following methods:

:addAnswer(type, content[, ttl, name])

Add an answer to the record of type with content.

Parameters:
  • type (int) – The type of record to add, can be pdns.AAAA etc.
  • content (str) – The content of the record, will be parsed into wireformat based on the type
  • ttl (int) – The TTL in seconds for this record
  • name (DNSName) – The name of this record, defaults to DNSQuestion.qname
:addPolicyTag(tag)

Add a policy tag.

Parameters:tag (str) – The tag to add
:discardPolicy(policyname)

Skip the filtering policy (for example RPZ) named policyname for this query. This is mostly useful in the prerpz hook.

Parameters:policyname (str) – The name of the policy to ignore.
:getDH() → DNSHeader

Returns the DNSHeader of the query or nil.

:getPolicyTags() → {str}

Get the current policy tags as a table of strings.

:getRecords() → {DNSRecord}

Get a table of DNS Records in this DNS Question (or answer by now).

:setPolicyTags(tags)

Set the policy tags to tags, overwriting any existing policy tags.

Parameters:tags ({str}) – The policy tags
:setRecords(records)

After your edits, update the answers of this question

Parameters:records ({DNSRecord}) – The records to put in the packet
:getEDNSFlag(name) → bool

Returns true if the EDNS flag with name is set in the query.

Parameters:name (string) – Name of the flag.
:getEDNSFlags() → {str}

Returns a list of strings with all the EDNS flag mnemonics in the query.

:getEDNSOption(num) → str

Get the EDNS Option with number num as a bytestring.

:getEDNSOptions() → {str: str}

Get a map of all EDNS Options

:getEDNSSubnet() → Netmask

Returns the Netmask specified in the EDNSSubnet option, or empty if there was none.

:addPolicyTag(tag)

Add policyTag tag to the list of policyTags

Parameters:tag (str) – The tag to add
:getPolicyTags() → {str}

Get a list the policyTags for this message.

DNSHeader Object

The DNS header as returned by DNSQuestion:getDH() represents a header of a DNS message.

class DNSHeader
represents a header of a DNS message.
:getRD() → bool

The value of the Recursion Desired bit.

:getAA() → bool

The value of the Authoritative Answer bit.

:getAD() → bool

The value of the Authenticated Data bit.

:getCD() → bool

The value of the Checking Disabled bit.

:getTC() → bool

The value of the Truncation bit.

:getRCODE() → int

The Response Code of the query

:getOPCODE() → int

The Operation Code of the query

:getID() → int

The ID of the query

The EDNSOptionView Class

class EDNSOptionView

An object that represents the values of a single EDNS option

:count()
.. versionadded:: 4.2.0

The number of values for this EDNS option.

:getValues()
.. versionadded:: 4.2.0

Return a table of NULL-safe strings values for this EDNS option.

size

The size in bytes of the first value of this EDNS option.

:getContent()

Returns a NULL-safe string object of the first value of this EDNS option.