Do53 and DoH (POST) basic queries implemented

internal/protocols/do53/do53.go

@@ -0,0 +1,63 @@
+package do53
+
+import (
+	"fmt"
+	"net"
+
+	"golang.org/x/net/dns/dnsmessage"
+)
+
+func Run(domain, queryType, dest string, dnssec bool) error {
+
+	message, err := MakeDNSMessage(domain, queryType)
+	if err != nil {
+		return err
+	}
+
+	udpAddr, err := net.ResolveUDPAddr("udp", dest)
+	if err != nil {
+		return fmt.Errorf("failed to resolve UDP address: %v", err)
+	}
+
+	udpConn, err := net.DialUDP("udp", nil, udpAddr)
+	if err != nil {
+		return fmt.Errorf("failed to dial UDP connection: %v", err)
+	}
+	defer udpConn.Close()
+
+	_, err = udpConn.Write(message)
+	if err != nil {
+		return fmt.Errorf("failed to send DNS query: %v", err)
+	}
+
+	buf := make([]byte, 4096)
+	n, err := udpConn.Read(buf)
+	if err != nil {
+		return fmt.Errorf("failed to read DNS response: %v", err)
+	}
+
+	var parser dnsmessage.Parser
+	_, err = parser.Start(buf[:n])
+	if err != nil {
+		return fmt.Errorf("failed to parse DNS response: %v", err)
+	}
+
+	// TODO: Check if the response had no errors or TD bit set
+
+	err = parser.SkipAllQuestions()
+	if err != nil {
+		return fmt.Errorf("failed to skip questions: %v", err)
+	}
+
+	answers, err := parser.AllAnswers()
+	if err != nil {
+		return err
+	}
+
+	for _, answer := range answers {
+		fmt.Println(answer.GoString())
+	}
+
+	return nil
+}
+

internal/protocols/do53/packet.go

@@ -0,0 +1,60 @@
+package do53
+
+import (
+	"fmt"
+
+	"golang.org/x/net/dns/dnsmessage"
+)
+
+func MakeDNSMessage(domain string, queryType string) ([]byte, error) {
+	messageHeader := dnsmessage.Header{
+		ID:               1234, // FIX: Use a random ID
+		Response:         false,
+		OpCode:           dnsmessage.OpCode(0),
+		RecursionDesired: true,
+	}
+
+	messageBuilder := dnsmessage.NewBuilder(nil, messageHeader)
+	queryName, err := dnsmessage.NewName(domain)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create query name: %v", err)
+	}
+
+	// Determine query type
+	var queryTypeValue dnsmessage.Type
+	switch queryType {
+	case "A":
+		queryTypeValue = dnsmessage.TypeA
+	case "AAAA":
+		queryTypeValue = dnsmessage.TypeAAAA
+	case "MX":
+		queryTypeValue = dnsmessage.TypeMX
+	case "CNAME":
+		queryTypeValue = dnsmessage.TypeCNAME
+	case "TXT":
+		queryTypeValue = dnsmessage.TypeTXT
+	default:
+		queryTypeValue = dnsmessage.TypeA
+	}
+
+	messageQuestion := dnsmessage.Question{
+		Name:  queryName,
+		Type:  queryTypeValue,
+		Class: dnsmessage.ClassINET,
+	}
+
+	err = messageBuilder.StartQuestions()
+	if err != nil {
+		return nil, err
+	}
+	err = messageBuilder.Question(messageQuestion)
+	if err != nil {
+		return nil, fmt.Errorf("failed to add question: %v", err)
+	}
+
+	message, err := messageBuilder.Finish()
+	if err != nil {
+		return nil, fmt.Errorf("failed to build message: %v", err)
+	}
+	return message, nil
+}