77 lines
2.0 KiB
C++
77 lines
2.0 KiB
C++
#include "dnsmessages.hh"
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#include "dns-types.hh"
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using namespace std;
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dnsname DNSMessageReader::getName()
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{
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dnsname name;
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for(;;) {
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uint8_t labellen=payload.getUInt8();
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if(labellen > 63)
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throw std::runtime_error("Got a compressed label");
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if(!labellen) // end of dnsname
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break;
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dnslabel label = payload.getBlob(labellen);
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name.push_back(label);
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}
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return name;
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}
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void DNSMessageReader::getQuestion(dnsname& name, DNSType& type)
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{
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name=getName();
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type=(DNSType)payload.getUInt16();
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}
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void DNSMessageWriter::putRR(DNSSection section, const dnsname& name, DNSType type, uint32_t ttl, const std::unique_ptr<RRGenerator>& content)
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{
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auto cursize = payload.payloadpos;
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try {
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putName(payload, name);
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payload.putUInt16((int)type); payload.putUInt16(1);
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payload.putUInt32(ttl);
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auto pos = payload.putUInt16(0); // placeholder
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content->toMessage(*this);
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payload.putUInt16At(pos, payload.payloadpos-pos-2);
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}
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catch(...) {
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payload.payloadpos = cursize;
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throw;
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}
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switch(section) {
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case DNSSection::Question:
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throw runtime_error("Can't add questions to a DNS Message with putRR");
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case DNSSection::Answer:
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dh.ancount = htons(ntohs(dh.ancount) + 1);
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break;
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case DNSSection::Authority:
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dh.nscount = htons(ntohs(dh.nscount) + 1);
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break;
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case DNSSection::Additional:
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dh.arcount = htons(ntohs(dh.arcount) + 1);
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break;
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}
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}
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void DNSMessageWriter::setQuestion(const dnsname& name, DNSType type)
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{
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dh.ancount = dh.arcount = dh.nscount = 0;
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payload.rewind();
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putName(payload, name);
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payload.putUInt16((uint16_t)type);
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payload.putUInt16(1); // class
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}
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string DNSMessageReader::serialize() const
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{
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return string((const char*)this, (const char*)this + sizeof(dnsheader) + payload.payloadpos);
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}
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string DNSMessageWriter::serialize() const
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{
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return string((const char*)this, (const char*)this + sizeof(dnsheader) + payload.payloadpos);
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}
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static_assert(sizeof(DNSMessageReader) == 516, "dnsmessagereader size must be 516");
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