Initial commit

pipe/backend/query.go

@@ -0,0 +1,85 @@
+package backend
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+// Represents a query received by the backend. Certain fields may be blank,
+// depending on negotiated protocol version - which is stored in ProtocolVersion
+//
+// QName, QClass, QType, Id and RemoteIpAddress are present in all versions
+// LocalIpAddress was added in version 2
+// EdnsSubnetAddress was added in version 3
+type Query struct {
+	ProtocolVersion   int
+	QName             string
+	QClass            string
+	QType             string
+	Id                string
+	RemoteIpAddress   string
+	LocalIpAddress    string
+	EdnsSubnetAddress string
+}
+
+func (q *Query) fromData(data string) (err error) {
+	parts := strings.Split(data, "\t")
+
+	// ugh
+	switch q.ProtocolVersion {
+	case 1:
+		if len(parts) != 5 {
+			return errors.New("v1 query should have 5 data parts")
+		}
+	case 2:
+		if len(parts) != 6 {
+			return errors.New("v2 query should have 6 data parts")
+		}
+		q.LocalIpAddress = parts[5]
+	case 3:
+		if len(parts) != 7 {
+			return errors.New("v3 query should have 7 data parts")
+		}
+		q.LocalIpAddress = parts[5]
+		q.EdnsSubnetAddress = parts[6]
+	default:
+		return errors.New("Unknown protocol version in query")
+	}
+
+	// common
+	q.QName = parts[0]
+	q.QClass = parts[1]
+	q.QType = parts[2]
+	q.Id = parts[3]
+	q.RemoteIpAddress = parts[4]
+
+	return nil
+}
+
+func (q *Query) String() (string, error) {
+	if q.ProtocolVersion < 1 || q.ProtocolVersion > 3 {
+		return "", errors.New("Unknown protocol version in query")
+	}
+	switch q.ProtocolVersion {
+	case 1:
+		return fmt.Sprintf(
+			"Q\t%s\t%s\t%s\t%s\t%s\n",
+			q.QName, q.QClass, q.QType, q.Id, q.RemoteIpAddress,
+		), nil
+	case 2:
+		return fmt.Sprintf(
+			"Q\t%s\t%s\t%s\t%s\t%s\t%s\n",
+			q.QName, q.QClass, q.QType, q.Id, q.RemoteIpAddress,
+			q.LocalIpAddress,
+		), nil
+	case 3:
+		return fmt.Sprintf(
+			"Q\t%s\t%s\t%s\t%s\t%s\t%s\t%s\n",
+			q.QName, q.QClass, q.QType, q.Id, q.RemoteIpAddress,
+			q.LocalIpAddress, q.EdnsSubnetAddress,
+		), nil
+	}
+
+	return "", errors.New("Unknown protocol version in query")
+}