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83
DNSPacket(const DNSPacket &orig);
76
int expand(const unsigned char *begin, const unsigned char *end, string &expanded, int depth=0);
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inline int parse(const char *mesg, int len); //!< parse a raw UDP or TCP packet and suck the data inward
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//! the raw DNS header
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unsigned int id:16; //!< id of this query/response
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#ifdef WORDS_BIGENDIAN // ultrasparc
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unsigned int qr:1; //!< 1 if this is a query, 0 if response
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unsigned int opcode:4; //!< the opcode
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unsigned int aa:1; //!< packet contains authoritative data
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unsigned int tc:1; //!< packet is truncated
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unsigned int rd:1; //!< this packets wants us to recurse
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unsigned int ra:1; //!< ??
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unsigned int unused:1; //!<
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unsigned int ad:1; //!< authentic data
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unsigned int cd:1; //!< checking disabled by resolver
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unsigned int rcode:4; //!< ??
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unsigned int rd:1; //!< this packets wants us to recurse
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unsigned int tc:1; //!< packet is truncated
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unsigned int aa:1; //!< packet contains authoritative data
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unsigned int opcode:4; //!< the opcode
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unsigned int qr:1; //!< 1 if this is a query, 0 if response
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unsigned int rcode:4; //!< ??
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unsigned int cd:1; //!< checking disabled by resolver
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unsigned int ad:1; //!< authentic data
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unsigned int unused:1; //!<
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unsigned int ra:1; //!< ??
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unsigned int qdcount:16; //!< number of questions
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unsigned int ancount:16; //!< number of answers
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unsigned int nscount:16; //!< number of authoritative nameservers included in answer
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unsigned int arcount:16; //!< number of additional resource records
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inline void setRemote(const struct sockaddr *a, Utility::socklen_t socklen);
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string getLocal() const;
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int parse(const char *mesg, int len); //!< parse a raw UDP or TCP packet and suck the data inward
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string getString(); //!< for serialization - just passes the whole packet
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// address & socket manipulation
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void setRemote(const ComboAddress*);
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string getRemote() const;
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string getLocal() const
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socklen_t len=sizeof(ca);
95
getsockname(d_socket, (sockaddr*)&ca, &len);
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uint16_t getRemotePort() const;
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void setA(bool); //!< make this packet authoritative
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void setRA(bool); //!< set the Recursion Available flag
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void setRD(bool); //!< set the Recursion Desired flag
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void setAnswer(bool); //!< Make this packet an answer
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void setID(uint16_t); //!< set the DNS id of this packet
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void setOpcode(uint16_t); //!< set the Opcode of this packet
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void setRcode(int v); //!< set the Rcode of this packet
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Utility::sock_t getSocket() const
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void setSocket(Utility::sock_t sock);
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// these manipulate 'd'
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void setA(bool); //!< make this packet authoritative - manipulates 'd'
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void setID(uint16_t); //!< set the DNS id of this packet - manipulates 'd'
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void setRA(bool); //!< set the Recursion Available flag - manipulates 'd'
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void setRD(bool); //!< set the Recursion Desired flag - manipulates 'd'
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void setAnswer(bool); //!< Make this packet an answer - clears the 'stringbuffer' first, if passed 'true', does nothing otherwise, manipulates 'd'
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void setOpcode(uint16_t); //!< set the Opcode of this packet - manipulates 'd'
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void setRcode(int v); //!< set the Rcode of this packet - manipulates 'd'
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void clearRecords(); //!< when building a packet, wipe all previously added records (clears 'rrs')
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/** Add a DNSResourceRecord to this packet. A DNSPacket (as does a DNS Packet) has 4 kinds of resource records. Questions,
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Answers, Authority and Additional. See RFC 1034 and 1035 for details. You can specify where a record needs to go in the
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DNSResourceRecord d_place field */
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void addRecord(const DNSResourceRecord &);
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/** helper function for both DNSPacket and addSOARecord() - converts a line into a struct, for easier parsing */
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static void fillSOAData(const string &content, SOAData &data);
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/** for use by DNSPacket, converts a SOAData class to a ascii line again */
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static string serializeSOAData(const SOAData &data);
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void setQuestion(int op, const string &qdomain, int qtype);
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vector<DNSResourceRecord> getAnswers();
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string compress(const string &qd);
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void addARecord(const string&, uint32_t, uint32_t ttl, DNSResourceRecord::Place place); //!< add an A record to the packet
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void addARecord(const DNSResourceRecord &); //!< add an A record to the packet
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void addAAAARecord(const string &, unsigned char addr[16], uint32_t ttl, DNSResourceRecord::Place place); //!< add an A record to the packet
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void addAAAARecord(const DNSResourceRecord &); //!< add an A record to the packet
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void addMXRecord(const string &domain, const string &mx, int priority, uint32_t ttl); //!< add an MX record to the packet
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void addMXRecord(const DNSResourceRecord &); //!< add an MX record to the packet
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void addSRVRecord(const string &domain, const string &srv, int priority, uint32_t ttl); //!< add an SRVMX record to the packet
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void addSRVRecord(const DNSResourceRecord &); //!< add an SRV record to the packet
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void addCNAMERecord(const string &domain, const string &alias, uint32_t ttl); //!< add a CNAME record to the packet
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void addCNAMERecord(const DNSResourceRecord &); //!< add a CNAME record to the packet
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void addRPRecord(const string &domain, const string &content, uint32_t ttl); //!< add a RP record to the packet
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void addRPRecord(const DNSResourceRecord &); //!< add a RP record to the packet
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void addNAPTRRecord(const string &domain, const string &content, uint32_t ttl); //!< add a NAPTR record to the packet
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void addNAPTRRecord(const DNSResourceRecord &); //!< add a NAPTR record to the packet
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void addPTRRecord(const string &domain, const string &alias, uint32_t ttl); //!< add a PTR record to the packet
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void addPTRRecord(const DNSResourceRecord &); //!< add a PTR record to the packet
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void addLOCRecord(const string &domain, const string &content, uint32_t ttl);
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void addLOCRecord(const DNSResourceRecord &); //!< add a LOC record to the packet
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/** Adds a SOA record to the packet. The SOA record is very special because we have a lot of default values,
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that may be overridden by the contents of the database. Content can have a variety of content:
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hostmaster serial-number
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hostmaster serial-number [refresh [retry [expire [ minimum] ] ] ]
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Suggested values are:
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10800 ;refresh every three hours
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300 ;retry every 5 min
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604800 ;expire after a week
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An empty field means that we supply hostmaster+@+domain name as hostmaster. An empty serial number is replaced by the
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number of seconds since 1 jan 1970 (unix timestamp). The other values are substituted as indicated
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void addSOARecord(const string &domain, const string &content, uint32_t ttl, DNSResourceRecord::Place place);
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void addSOARecord(const DNSResourceRecord &); //!< add a SOA record to the packet
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void addTXTorSPFRecord(uint16_t qtype, string domain, string, uint32_t ttl); //!< add a TXT or SPF record to the packet
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void addTXTRecord(const DNSResourceRecord &); //!< add a TXT record to the packet
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void addSPFRecord(const DNSResourceRecord &); //!< add a SPF record to the packet
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void addHINFORecord(string domain, string, uint32_t ttl); //!< add a HINFO record to the packet
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void addHINFORecord(const DNSResourceRecord &); //!< add a HINFO record to the packet
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void addNSRecord(string domain, string server, uint32_t ttl, DNSResourceRecord::Place place); //!< add an NS record to the packet
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void addNSRecord(const DNSResourceRecord &); //!< add an NS record to the packet
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void addGenericRecord(const DNSResourceRecord& rr);
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static string &attodot(string &str); //!< for when you need to insert an email address in the SOA
122
void addRecord(const DNSResourceRecord &); // adds to 'rrs'
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void setQuestion(int op, const string &qdomain, int qtype); // wipes 'd', sets a random id, creates start of packet (label, type, class etc)
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DTime d_dt; //!< the time this packet was created. replyPacket() copies this in for you, so d_dt becomes the time spent processing the question+answer
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void pasteQ(const char *question, int length); //!< set the question of this packet, useful for crafting replies
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inline const char *getData(void); //!< get binary representation of packet
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void setRaw(char *mesg, int length);
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const char *getRaw(void);
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inline void spoofID(uint16_t id); //!< change the ID of an existing packet. Useful for fixing up packets returned from the PacketCache
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inline void spoofQuestion(const string &qd); //!< paste in the exact right case of the question. Useful for PacketCache
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void wrapup(void); // writes out queued rrs, and generates the binary packet. also shuffles. also rectifies dnsheader 'd', and copies it to the stringbuffer
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const char *getData(void); //!< get binary representation of packet, will call 'wrapup' for you
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const char *getRaw(void); //!< provides access to the raw packet, possibly on a packet that has never been 'wrapped'
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void spoofID(uint16_t id); //!< change the ID of an existing packet. Useful for fixing up packets returned from the PacketCache
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void spoofQuestion(const string &qd); //!< paste in the exact right case of the question. Useful for PacketCache
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void truncate(int new_length); // has documentation in source
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bool needAP(); //!< query this to find out if this packet needs additional processing
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vector<DNSResourceRecord*> getAPRecords(); //!< get a vector with DNSResourceRecords that need additional processing
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void setCompress(bool compress);
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DNSPacket *replyPacket() const; //!< convenience function that creates a virgin answer packet to this question
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Utility::sock_t getSocket() const
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inline void setSocket(Utility::sock_t sock);
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inline void commitD();
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static bool isRD(const string &buffer)
236
return ((struct dnsheader *)buffer.c_str())->rd;
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void commitD(); //!< copies 'd' into the stringbuffer
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char remote[sizeof(sockaddr_in6)];
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Utility::socklen_t d_socklen; // 4
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uint16_t len; //!< length of the raw binary packet 2
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uint16_t qclass; //!< class of the question - should always be INternet 2
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struct dnsheader d; //!< dnsheader at the start of the databuffer 12
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QType qtype; //!< type of the question 8
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string qdomain; //!< qname of the question 4
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string qdomain; //!< qname of the question 4 - unsure how this is used
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void pasteQ(const char *question, int length); //!< set the question of this packet, useful for crafting replies
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bool d_wrapped; // 1
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bool d_compress; // 1
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uint16_t d_qlen; // length of the question (including class & type) in this packet 2
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int d_socket; // 4
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int findlabel(string &label);
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int toqname(const char *name, string &qname, bool compress = true);
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int toqname(const string &name, string &qname, bool compress = true);
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int toqname(const string &name, string *qname, bool compress = true);
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const string makeSoaHostmasterPiece(const string &hostmaster);
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static string parseLOC(const unsigned char *p, unsigned int length);
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void makeHeader(char *p,uint16_t qtype, uint32_t ttl);
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string stringbuffer; // this is where everything lives 4
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inline void DNSPacket::spoofQuestion(const string &qd)
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string label=compress(qd);
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for(string::size_type i=0;i<label.size();++i)
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stringbuffer[i+sizeof(d)]=label[i];
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d_wrapped=true; // if we do this, don't later on wrapup
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/** This function takes data from the network, possibly received with recvfrom, and parses
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it into our class. Results of calling this function multiple times on one packet are
286
unknown. Returns -1 if the packet cannot be parsed.
288
int DNSPacket::parse(const char *mesg, int length)
290
stringbuffer.assign(mesg,length);
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L << Logger::Warning << "Ignoring packet: too short from "
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<< getRemote() << endl;
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memcpy((void *)&d,(const void *)stringbuffer.c_str(),12);
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if(!ntohs(d.qdcount)) {
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L << Logger::Warning << "No question section in packet from " << getRemote() <<", rcode="<<(int)d.rcode<<endl;
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offset = getq(); // also sets this->qdomain!
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d_qlen=offset+4; // this points to the start of any answers
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// L << Logger::Warning << "Ignoring packet: invalid label in question from "
315
// << inet_ntoa(remote.sin_addr) << endl;
318
if(qdomain.length() > 255) { // this prevents crap from the rootservers
324
if((unsigned int)(15+offset)>=stringbuffer.length()) {
325
L << Logger::Warning << "Ignoring packet: question too short from "<< getRemote()<<", offset "<<
326
15+offset<<">="<<stringbuffer.length()<<endl;
330
qtype=((unsigned char)stringbuffer[12+offset])*256+(unsigned char)stringbuffer[13+offset];
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qclass=((unsigned char)stringbuffer[14+offset]*256)+(unsigned char)stringbuffer[15+offset];
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//! Use this to set where this packet was received from or should be sent to
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inline void DNSPacket::setRemote(const struct sockaddr *s, Utility::socklen_t socklen)
338
if(socklen>(Utility::socklen_t)sizeof(remote))
339
throw AhuException("Address too long for storage: "+itoa(socklen));
341
memcpy((void *)remote,(void *)s,socklen);
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inline void DNSPacket::spoofID(uint16_t id)
347
stringbuffer[1]=(id>>8)&0xff;
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stringbuffer[0]=id&0xff;
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inline void DNSPacket::setSocket(Utility::sock_t sock)
357
inline void DNSPacket::commitD()
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stringbuffer.replace(0,12,(char *)&d,12); // copy in d
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inline const char *DNSPacket::getData(void)
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return stringbuffer.data();
added
removed
pdns/dnspacket.hh
