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z*Help for building DNS wire format messages )BytesION )long c @ st e Zd ZdZdddZdd Zd d
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ejjfddZdd Zdd ZdS )Rendererai Helper class for building DNS wire-format messages.
Most applications can use the higher-level L{dns.message.Message}
class and its to_wire() method to generate wire-format messages.
This class is for those applications which need finer control
over the generation of messages.
Typical use::
r = dns.renderer.Renderer(id=1, flags=0x80, max_size=512)
r.add_question(qname, qtype, qclass)
r.add_rrset(dns.renderer.ANSWER, rrset_1)
r.add_rrset(dns.renderer.ANSWER, rrset_2)
r.add_rrset(dns.renderer.AUTHORITY, ns_rrset)
r.add_edns(0, 0, 4096)
r.add_rrset(dns.renderer.ADDTIONAL, ad_rrset_1)
r.add_rrset(dns.renderer.ADDTIONAL, ad_rrset_2)
r.write_header()
r.add_tsig(keyname, secret, 300, 1, 0, '', request_mac)
wire = r.get_wire()
@ivar output: where rendering is written
@type output: BytesIO object
@ivar id: the message id
@type id: int
@ivar flags: the message flags
@type flags: int
@ivar max_size: the maximum size of the message
@type max_size: int
@ivar origin: the origin to use when rendering relative names
@type origin: dns.name.Name object
@ivar compress: the compression table
@type compress: dict
@ivar section: the section currently being rendered
@type section: int (dns.renderer.QUESTION, dns.renderer.ANSWER,
dns.renderer.AUTHORITY, or dns.renderer.ADDITIONAL)
@ivar counts: list of the number of RRs in each section
@type counts: int list of length 4
@ivar mac: the MAC of the rendered message (if TSIG was used)
@type mac: string
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@param id: the message id
@type id: int
@param flags: the DNS message flags
@type flags: int
@param max_size: the maximum message size; the default is 65535.
If rendering results in a message greater than I{max_size},
then L{dns.exception.TooBig} will be raised.
@type max_size: int
@param origin: the origin to use when rendering relative names
@type origin: dns.name.Name or None.
Nr i s )r outputrandomZrandintidflagsmax_sizeorigincompressQUESTIONsectioncountswritemac)selfr r r r r /usr/lib/python3.6/renderer.py__init__N s zRenderer.__init__c C s^ | j j| | j j g }x(| jj D ]\}}||kr&|j| q&W x|D ] }| j|= qJW dS )zTruncate the output buffer at offset I{where}, and remove any
compression table entries that pointed beyond the truncation
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@param where: the offset
@type where: int
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zRenderer._rollbackc C s& | j |kr"| j |kr tjj|| _ dS )aZ Set the renderer's current section.
Sections must be rendered order: QUESTION, ANSWER, AUTHORITY,
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@param section: the section
@type section: int
@raises dns.exception.FormError: an attempt was made to set
a section value less than the current section.
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j| jt d7 < dS )a Add a question to the message.
@param qname: the question name
@type qname: dns.name.Name
@param rdtype: the question rdata type
@type rdtype: int
@param rdclass: the question rdata class
@type rdclass: int
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| j | |7 < dS )a Add the rrset to the specified section.
Any keyword arguments are passed on to the rdataset's to_wire()
routine.
@param section: the section
@type section: int
@param rrset: the rrset
@type rrset: dns.rrset.RRset object
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name as the owner name.
Any keyword arguments are passed on to the rdataset's to_wire()
routine.
@param section: the section
@type section: int
@param name: the owner name
@type name: dns.name.Name object
@param rdataset: the rdataset
@type rdataset: dns.rdataset.Rdataset object
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7 < dS ) a Add an EDNS OPT record to the message.
@param edns: The EDNS level to use.
@type edns: int
@param ednsflags: EDNS flag values.
@type ednsflags: int
@param payload: The EDNS sender's payload field, which is the maximum
size of UDP datagram the sender can handle.
@type payload: int
@param options: The EDNS options list
@type options: list of dns.edns.Option instances
@see: RFC 2671
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a Add a TSIG signature to the message.
@param keyname: the TSIG key name
@type keyname: dns.name.Name object
@param secret: the secret to use
@type secret: string
@param fudge: TSIG time fudge
@type fudge: int
@param id: the message id to encode in the tsig signature
@type id: int
@param tsig_error: TSIG error code; default is 0.
@type tsig_error: int
@param other_data: TSIG other data.
@type other_data: string
@param request_mac: This message is a response to the request which
had the specified MAC.
@type request_mac: string
@param algorithm: the TSIG algorithm to use
@type algorithm: dns.name.Name object
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C sX | j jd | j jtjd| j| j| jd | jd | jd | jd | j jdd dS )zWrite the DNS message header.
Writing the DNS message header is done after all sections
have been rendered, but before the optional TSIG signature
is added.
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