mirror of https://github.com/oxen-io/lokinet
Jeff Becker
6 years ago
commit
f222f002f4
@ -0,0 +1,188 @@
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#include "dnsd.hpp" // for llarp_handle_dnsd_recvfrom, dnsc
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#include "logger.hpp"
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#include <string.h>
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uint16_t
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get16bits(const char *&buffer) throw()
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{
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uint16_t value = static_cast< unsigned char >(buffer[0]);
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value = value << 8;
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value += static_cast< unsigned char >(buffer[1]);
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buffer += 2;
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return value;
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}
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// uint32_t
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uint32_t
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get32bits(const char *&buffer) throw()
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{
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uint32_t value = uint32_t(
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(unsigned char)(buffer[0]) << 24 | (unsigned char)(buffer[1]) << 16
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| (unsigned char)(buffer[2]) << 8 | (unsigned char)(buffer[3]));
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buffer += 4;
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return value;
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}
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dns_msg_header *
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decode_hdr(const char *buffer)
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{
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dns_msg_header *hdr = new dns_msg_header;
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hdr->id = get16bits(buffer);
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uint fields = get16bits(buffer);
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uint8_t lFields = (fields & 0x00FF) >> 0;
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uint8_t hFields = (fields & 0xFF00) >> 8;
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// hdr->qr = fields & 0x8000;
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hdr->qr = (hFields >> 7) & 0x1;
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hdr->opcode = fields & 0x7800;
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hdr->aa = fields & 0x0400;
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hdr->tc = fields & 0x0200;
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hdr->rd = fields & 0x0100;
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hdr->ra = (lFields >> 7) & 0x1;
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//hdr->z = (lFields >> 6) & 0x1;
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//hdr->ad = (lFields >> 5) & 0x1;
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//hdr->cd = (lFields >> 4) & 0x1;
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hdr->rcode = lFields & 0xf;
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hdr->qdCount = get16bits(buffer);
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hdr->anCount = get16bits(buffer);
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hdr->nsCount = get16bits(buffer);
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hdr->arCount = get16bits(buffer);
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return hdr;
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}
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dns_msg_question *
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decode_question(const char *buffer)
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{
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dns_msg_question *question = new dns_msg_question;
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std::string m_qName = "";
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int length = *buffer++;
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// llarp::LogInfo("qNamLen", length);
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while(length != 0)
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{
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for(int i = 0; i < length; i++)
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{
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char c = *buffer++;
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m_qName.append(1, c);
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}
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length = *buffer++;
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if(length != 0)
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m_qName.append(1, '.');
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}
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question->name = m_qName;
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question->type = get16bits(buffer);
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question->qClass = get16bits(buffer);
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return question;
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}
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dns_msg_answer *
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decode_answer(const char *buffer)
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{
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dns_msg_answer *answer = new dns_msg_answer;
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answer->type = get16bits(buffer);
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//assert(answer->type < 259);
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if (answer->type > 259)
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{
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llarp::LogWarn("Answer type is off the charts");
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}
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answer->aClass = get16bits(buffer);
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answer->ttl = get32bits(buffer);
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answer->rdLen = get16bits(buffer);
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if (answer->rdLen == 4)
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{
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answer->rData = new uint8_t[answer->rdLen];
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memcpy(answer->rData, buffer, answer->rdLen);
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}
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else
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{
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llarp::LogWarn("Unknown Type ", answer->type);
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}
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return answer;
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}
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void
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put16bits(char *&buffer, uint16_t value) throw()
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{
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buffer[0] = (value & 0xFF00) >> 8;
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buffer[1] = value & 0xFF;
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buffer += 2;
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}
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void
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put32bits(char *&buffer, uint32_t value) throw()
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{
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buffer[0] = (value & 0xFF000000) >> 24;
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buffer[1] = (value & 0x00FF0000) >> 16;
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buffer[2] = (value & 0x0000FF00) >> 8;
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buffer[3] = (value & 0x000000FF) >> 0;
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buffer += 4;
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}
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void
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code_domain(char *&buffer, const std::string &domain) throw()
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{
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int start(0), end; // indexes
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// llarp::LogInfo("domain [", domain, "]");
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while((end = domain.find('.', start)) != std::string::npos)
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{
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*buffer++ = end - start; // label length octet
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for(int i = start; i < end; i++)
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{
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*buffer++ = domain[i]; // label octets
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// llarp::LogInfo("Writing ", domain[i], " at ", i);
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}
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start = end + 1; // Skip '.'
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}
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// llarp::LogInfo("start ", start, " domain size ", domain.size());
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*buffer++ = domain.size() - start; // last label length octet
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for(uint i = start; i < domain.size(); i++)
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{
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*buffer++ = domain[i]; // last label octets
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// llarp::LogInfo("Writing ", domain[i], " at ", i);
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}
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*buffer++ = 0;
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}
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void
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llarp_handle_dns_recvfrom(struct llarp_udp_io *udp,
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const struct sockaddr *saddr, const void *buf,
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ssize_t sz)
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{
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unsigned char *castBuf = (unsigned char *)buf;
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// auto buffer = llarp::StackBuffer< decltype(castBuf) >(castBuf);
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dns_msg_header *hdr = decode_hdr((const char *)castBuf);
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// castBuf += 12;
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llarp::LogDebug("msg id ", hdr->id);
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llarp::LogDebug("msg qr ", (uint8_t)hdr->qr);
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if(hdr->qr)
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{
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llarp::LogDebug("handling as dnsc answer");
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llarp_handle_dnsc_recvfrom(udp, saddr, buf, sz);
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}
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else
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{
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llarp::LogDebug("handling as dnsd question");
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llarp_handle_dnsd_recvfrom(udp, saddr, buf, sz);
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}
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/*
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llarp::LogInfo("msg op ", hdr->opcode);
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llarp::LogInfo("msg rc ", hdr->rcode);
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for(uint i = 0; i < hdr->qdCount; i++)
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{
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dns_msg_question *question = decode_question((const char*)castBuf);
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llarp::LogInfo("Read a question");
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castBuf += question->name.length() + 8;
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}
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for(uint i = 0; i < hdr->anCount; i++)
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{
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dns_msg_answer *answer = decode_answer((const char*)castBuf);
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llarp::LogInfo("Read an answer");
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castBuf += answer->name.length() + 4 + 4 + 4 + answer->rdLen;
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}
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*/
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}
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@ -0,0 +1,75 @@
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#ifndef LIBLLARP_DNS_HPP
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#define LIBLLARP_DNS_HPP
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#include <string>
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#include <sys/types.h> // for uint & ssize_t
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// protocol parsing/writing structures & functions
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struct dns_msg_header
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{
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uint16_t id;
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uint8_t qr:1;
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uint8_t opcode:4;
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uint8_t aa:1;
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uint8_t tc:1;
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uint8_t rd:1;
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uint8_t ra:1;
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uint8_t z:1;
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uint8_t ad:1;
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uint8_t cd:1;
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uint8_t rcode:4;
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uint16_t qdCount;
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uint16_t anCount;
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uint16_t nsCount;
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uint16_t arCount;
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};
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struct dns_msg_question
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{
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std::string name;
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uint16_t type;
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uint16_t qClass;
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};
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struct dns_msg_answer
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{
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std::string name;
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uint16_t type;
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uint16_t aClass;
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uint32_t ttl;
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uint16_t rdLen;
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uint8_t *rData;
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};
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uint16_t
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get16bits(const char *&buffer) throw();
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uint32_t
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get32bits(const char *&buffer) throw();
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dns_msg_header *
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decode_hdr(const char *buffer);
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dns_msg_question *
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decode_question(const char *buffer);
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dns_msg_answer *
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decode_answer(const char *buffer);
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void
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put16bits(char *&buffer, uint16_t value) throw();
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void
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put32bits(char *&buffer, uint32_t value) throw();
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void
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code_domain(char *&buffer, const std::string &domain) throw();
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void
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llarp_handle_dns_recvfrom(struct llarp_udp_io *udp,
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const struct sockaddr *saddr, const void *buf,
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ssize_t sz);
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#endif
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@ -1,6 +1,61 @@
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#ifndef LIBLLARP_DNSC_HPP
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#define LIBLLARP_DNSC_HPP
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#include <llarp/dns.h>
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#include <llarp/ev.h> // for sockaadr
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#include "dns.hpp" // get protocol structs
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// internal, non-public functions
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// well dnsc init/stop are public...
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struct dnsc_answer_request;
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// should we pass by llarp::Addr
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// not as long as we're supporting raw
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typedef void (*dnsc_answer_hook_func)(dnsc_answer_request *request);
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// FIXME: separate generic from llarp
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struct dnsc_answer_request
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{
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/// sock type
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void *sock; // pts to udp...
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/// customizable (used for hook (outer request))
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void *user;
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/// storage
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dns_msg_question question;
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/// hook
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dnsc_answer_hook_func resolved;
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/// result
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bool found;
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struct sockaddr result;
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// a reference to dnsc_context incase of multiple contexts
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struct dnsc_context *context;
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};
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void
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llarp_handle_dnsc_recvfrom(struct llarp_udp_io *udp,
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const struct sockaddr *saddr, const void *buf,
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ssize_t sz);
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void
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raw_handle_recvfrom(int *sockfd, const struct sockaddr *saddr, const void *buf,
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ssize_t sz);
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struct dnsc_context
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{
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/// Target: DNS server hostname/port to use
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// FIXME: ipv6 it
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sockaddr *server;
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// where to create the new sockets
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struct llarp_udp_io *udp;
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};
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/// initialize dns subsystem and bind socket
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/// returns true on bind success otherwise returns false
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bool
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llarp_dnsc_init(struct dnsc_context *dnsc, struct llarp_udp_io *udp,
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const char *dnsc_hostname, uint16_t dnsc_port);
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bool
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llarp_dnsc_stop(struct dnsc_context *dnsc);
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#endif
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@ -1,40 +1,62 @@
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#ifndef LIBLLARP_DNSD_HPP
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#define LIBLLARP_DNSD_HPP
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#include <string>
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#include "dns.hpp" // question and dnsc
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#include "dnsc.hpp"
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#include <llarp/ev.h> // for sockaadr
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#include <string>
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struct dns_msg
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{
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uint id;
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uint qr;
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uint opcode;
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uint aa;
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uint tc;
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uint rd;
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uint ra;
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uint rcode;
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uint qdCount;
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uint anCount;
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uint nsCount;
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uint arCount;
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};
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struct dnsd_context;
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typedef ssize_t (*sendto_dns_hook_func)(void *sock, const struct sockaddr *from,
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const void *buffer, size_t length);
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struct dns_request
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struct dnsd_question_request
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{
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/// sock type
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void *user;
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// raw or llarp subsystem
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bool llarp;
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/// request id
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int id;
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std::string m_qName;
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uint m_qType;
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uint m_qClass;
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/// question being asked
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dns_msg_question question;
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// request source socket
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struct sockaddr *from;
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sendto_dns_hook_func hook; // sendto hook tbh
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// maybe a reference to dnsd_context incase of multiple
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dnsd_context *context; // or you can access it via user (udp)
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};
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// we could have passed in the source sockaddr in case you wanted to
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// handle the response yourself
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typedef sockaddr *(*intercept_query_hook)(std::string name);
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struct dnsd_context
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{
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/// DNS daemon socket to listen on
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struct llarp_udp_io udp;
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dnsc_context client;
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/// custom data for intercept query hook
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void *user;
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/// hook function for intercepting dns requests
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intercept_query_hook intercept;
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};
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void
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llarp_handle_dnsd_recvfrom(struct llarp_udp_io *udp,
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const struct sockaddr *paddr, const void *buf,
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ssize_t sz);
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/// initialize dns subsystem and bind socket
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/// returns true on bind success otherwise returns false
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bool
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llarp_dnsd_init(struct dnsd_context *dnsd, struct llarp_ev_loop *netloop,
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const char *dnsd_ifname, uint16_t dnsd_port,
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const char *dnsc_hostname, uint16_t dnsc_port);
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bool
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llarp_dnsd_stop(struct dnsd_context *dnsd);
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#endif
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