Implemented the letsencrypt challange

server/src/handler.cpp

@@ -69,6 +69,18 @@ void WebDNSHandler::handle_message(const std::shared_ptr<DNSServerBinding>& bind
 				a.set_type(query->qtype());
 				a.set_ttl(120);
 				a.builder<rrbuilder::A>().set_address(resp);
+			} else if(query->qclass() == rrclass::IN && query->qtype() == rrtype::TXT) {
+				auto dn = query->qname();
+				if(dn == "_acme-challenge.con-gate.work") {
+					std::cout << "  Letsencrypt request\n";
+					std::cout << "  Sending predefined key\n";
+
+					auto& a = response.push_answer(query->qname());
+					a.set_class(query->qclass());
+					a.set_type(query->qtype());
+					a.set_ttl(120);
+					a.builder<rrbuilder::TXT>().set_text("-YEqeIGJqoOz5uLbUiUfK06--n3jtVoI__6WJY-Ehgk");
+				}
 			}
 		}
 

util/include/teadns/builder.h

@@ -143,6 +143,12 @@ namespace ts::dns {
 					uint32_t address{0};
 			);
 
+			define_builder(TXT, base,
+	               inline void set_text(const std::string& text) { this->_text = text; }
+	            private:
+	               std::string _text;
+			);
+
 			#undef define_builder
 		}
 	}

util/src/builder.cpp

@@ -119,4 +119,17 @@ bool rrbuilder::A::build(char *&buffer, size_t &max_size, std::string &error) {
 	buffer += 4;
 	max_size -= 4;
 	return true;
+}
+
+bool rrbuilder::TXT::build(char *&buffer, size_t &max_size, std::string &error) {
+	if(max_size + 1 < this->_text.size()) {
+		error = "buffer too small";
+		return false;
+	}
+
+	*buffer = this->_text.size();
+	memcpy(buffer + 1, this->_text.data(), this->_text.size());
+	buffer += this->_text.size() + 1;
+	max_size -= this->_text.size() + 1;
+	return true;
 }