a sd__"ã@s^dZddlZddlZddlZddlZddlZddlZddlZdZ dZ dZ dZ Gdd„dƒZ dS)z*Help for building DNS wire format messageséNéééc@sšeZdZdZddd„Zdd„Zd d „Zejd d „ƒZ e j j fd d„Z dd„Zdd„Zd dd„Ze jjfdd„Ze jjfdd„Zdd„Zdd„Zdd„ZdS)!ÚRendereraùHelper 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() output, an io.BytesIO, where rendering is written id: the message id flags: the message flags max_size: the maximum size of the message origin: the origin to use when rendering relative names compress: the compression table section: an int, the section currently being rendered counts: list of the number of RRs in each section mac: the MAC of the rendered message (if TSIG was used) NréÿÿcCsft ¡|_|dur"t dd¡|_n||_||_||_||_i|_ t |_ gd¢|_ |j  d¡d|_dS)zInitialize a new renderer.Nrr)rrrrs Ú)ÚioÚBytesIOÚoutputÚrandomZrandintÚidÚflagsÚmax_sizeÚoriginÚcompressÚQUESTIONÚsectionÚcountsÚwriteZmac)Úselfr r rr©rú./usr/lib/python3/dist-packages/dns/renderer.pyÚ__init__Ms   zRenderer.__init__cCsV|j |¡|j ¡g}|j ¡D]\}}||kr$| |¡q$|D] }|j|=qDdS)z™Truncate the output buffer at offset *where*, and remove any compression table entries that pointed beyond the truncation point. N)r ÚseekÚtruncaterÚitemsÚappend)rÚwhereZkeys_to_deleteÚkÚvrrrÚ _rollback^s   zRenderer._rollbackcCs&|j|kr"|j|krtjj‚||_dS)aSet the renderer's current section. Sections must be rendered order: QUESTION, ANSWER, AUTHORITY, ADDITIONAL. Sections may be empty. Raises dns.exception.FormError if an attempt was made to set a section value less than the current section. N)rÚdnsÚ exceptionZ FormError)rrrrrÚ _set_sectionms  zRenderer._set_sectionccs6|j ¡}|V|j ¡|jkr2| |¡tjj‚dS)N)r Útellrr r!r"ZTooBig)rÚstartrrrÚ _track_size|s   zRenderer._track_sizecCsr| t¡| ¡:| |j|j|j¡|j t  d||¡¡Wdƒn1sR0Y|j td7<dS)zAdd a question to the message.z!HHNr) r#rr&Úto_wirer rrrÚstructÚpackr)rZqnameZrdtypeZrdclassrrrÚ add_question„s   4zRenderer.add_questioncKsd| |¡| ¡,|j|j|j|jfi|¤Ž}Wdƒn1sD0Y|j||7<dS)zŠAdd the rrset to the specified section. Any keyword arguments are passed on to the rdataset's to_wire() routine. N©r#r&r'r rrr)rrZrrsetÚkwÚnrrrÚ add_rrsets  :zRenderer.add_rrsetcKsf| |¡| ¡.|j||j|j|jfi|¤Ž}Wdƒn1sF0Y|j||7<dS)zÁAdd the rdataset to the specified section, using the specified name as the owner name. Any keyword arguments are passed on to the rdataset's to_wire() routine. Nr+)rrÚnameZrdatasetr,r-rrrÚ add_rdataset™s   ÿ$zRenderer.add_rdatasetcCs6|dM}||d>O}tjj |||¡}| t|¡dS)z&Add an EDNS OPT record to the message.lÿ~éN)r!ÚmessageÚMessageZ _make_optr.Ú ADDITIONAL)rZednsZ ednsflagsZpayloadZoptionsZoptrrrÚadd_edns§s zRenderer.add_ednsc Cs~|j ¡} t|tjjƒr|} ntj |||¡} tjj ||d|d|||¡} tj  | | | dt t   ¡ƒ|¡\} } |  | |¡dS)z$Add a TSIG signature to the message.róN© r ÚgetvalueÚ isinstancer!ÚtsigZKeyr2r3Z _make_tsigZsignÚintÚtimeÚ _write_tsig) rÚkeynameÚsecretÚfudger Ú tsig_errorÚ other_dataÚ request_macÚ algorithmÚsÚkeyr:Ú_rrrÚadd_tsig°s ÿÿzRenderer.add_tsigc Cs‚|j ¡} t|tjjƒr|} ntj ||| ¡} tjj || d|d|||¡} tj  | | | dt t   ¡ƒ||d¡\} }|  | |¡|S)ayAdd a TSIG signature to the message. Unlike add_tsig(), this can be used for a series of consecutive DNS envelopes, e.g. for a zone transfer over TCP [RFC2845, 4.4]. For the first message in the sequence, give ctx=None. For each subsequent message, give the ctx that was returned from the add_multi_tsig() call for the previous message.rr6Tr7) rÚctxr>r?r@r rArBrCrDrErFr:rrrÚadd_multi_tsigÀs ÿÿ zRenderer.add_multi_tsigc Csü| t¡| ¡\| |j|j|j¡|j t  dt j j t j jdd¡¡|j ¡}| |j¡Wdƒn1st0Y|j ¡}|j |d¡|j t  d||¡¡|jtd7<|j d¡|j t  d|jt¡¡|j dtj¡dS)Nz!HHIHrrz!Hré )r#r4r&r'r rrrr(r)r!Z rdatatypeZTSIGÚ rdataclassÚANYr$rrrÚSEEK_END)rr:r>Z rdata_startZafterrrrr=Øs   ÿ *  zRenderer._write_tsigc CsZ|j d¡|j t d|j|j|jd|jd|jd|jd¡¡|j dtj ¡dS)z¾Write the DNS message header. Writing the DNS message header is done after all sections have been rendered, but before the optional TSIG signature is added. rz!HHHHHHrrrN) r rrr(r)r r rrrN©rrrrÚ write_headerés  þzRenderer.write_headercCs |j ¡S)zReturn the wire format message.)r r8rOrrrÚget_wire÷szRenderer.get_wire)NrrN)N)Ú__name__Ú __module__Ú __qualname__Ú__doc__rr r#Ú contextlibÚcontextmanagerr&r!rLÚINr*r.r0r5r:Zdefault_algorithmrHrJr=rPrQrrrrr$s"(     ÿ þ r)rUrVrr(r r<Z dns.exceptionr!Zdns.tsigrZANSWERZ AUTHORITYr4rrrrrÚs