hello-dns/tdns/dnsmessages.hh

117 lines
2.8 KiB
C++

#pragma once
#include "dns.hh"
#include "dns-storage.hh"
#include "record-types.hh"
#include <arpa/inet.h>
#include <vector>
class DNSMessageReader
{
public:
DNSMessageReader(const char* input, uint16_t length);
DNSMessageReader(const std::string& str) : DNSMessageReader(str.c_str(), str.size()) {}
struct dnsheader dh=dnsheader{};
std::vector<uint8_t> payload;
uint16_t payloadpos{0};
void getQuestion(DNSName& name, DNSType& type) const;
bool getEDNS(uint16_t* newsize, bool* doBit) const;
uint8_t d_ednsVersion{0};
private:
DNSName getName();
uint8_t getUInt8()
{
return payload.at(payloadpos++);
}
uint16_t getUInt16()
{
uint16_t ret;
memcpy(&ret, &payload.at(payloadpos+1)-1, 2);
payloadpos+=2;
return htons(ret);
}
std::string getBlob(int size)
{
std::string ret(&payload.at(payloadpos), &payload.at(payloadpos+size));
payloadpos += size;
return ret;
}
DNSName d_qname;
DNSType d_qtype;
DNSClass d_qclass;
uint16_t d_bufsize;
bool d_doBit{false};
bool d_haveEDNS{false};
};
class DNSMessageWriter
{
public:
struct dnsheader dh=dnsheader{};
std::vector<uint8_t> payload;
uint16_t payloadpos=0;
DNSName d_qname;
DNSType d_qtype;
DNSClass d_qclass;
bool haveEDNS{false};
bool d_doBit;
bool d_nocompress{false}; // if set, never compress. For AXFR/IXFR
RCode d_ercode{(RCode)0};
DNSMessageWriter(const DNSName& name, DNSType type, int maxsize=500);
~DNSMessageWriter();
DNSMessageWriter(const DNSMessageWriter&) = delete;
DNSMessageWriter& operator=(const DNSMessageWriter&) = delete;
void clearRRs();
void putRR(DNSSection section, const DNSName& name, DNSType type, uint32_t ttl, const std::unique_ptr<RRGen>& rr);
void setEDNS(uint16_t bufsize, bool doBit, RCode ercode = (RCode)0);
std::string serialize();
void putUInt8(uint8_t val)
{
payload.at(payloadpos++)=val;
}
uint16_t putUInt16(uint16_t val)
{
val = htons(val);
memcpy(&payload.at(payloadpos+2)-2, &val, 2);
payloadpos+=2;
return payloadpos - 2;
}
void putUInt16At(uint16_t pos, uint16_t val)
{
val = htons(val);
memcpy(&payload.at(pos+2)-2, &val, 2);
}
void putUInt32(uint32_t val)
{
val = htonl(val);
memcpy(&payload.at(payloadpos+sizeof(val)) - sizeof(val), &val, sizeof(val));
payloadpos += sizeof(val);
}
void putBlob(const std::string& blob)
{
memcpy(&payload.at(payloadpos+blob.size()) - blob.size(), blob.c_str(), blob.size());
payloadpos += blob.size();;
}
void putBlob(const unsigned char* blob, int size)
{
memcpy(&payload.at(payloadpos+size) - size, blob, size);
payloadpos += size;
}
void putName(const DNSName& name, bool compress=true);
private:
std::unique_ptr<DNSNode> d_comptree;
void putEDNS(uint16_t bufsize, RCode ercode, bool doBit);
};