Try to sniff every packet

pkg/mcproto/types.go

@@ -5,6 +5,8 @@ import (
 	"errors"
 	"io"
 	"strings"
+
+	"github.com/sirupsen/logrus"
 )
 
 type Frame struct {
@@ -38,6 +40,12 @@ func ReadVarInt(reader io.Reader) (int, error) {
 	for numRead <= 5 {
 		n, err := reader.Read(b)
 		if err != nil {
+			logrus.WithError(err).WithFields(logrus.Fields{
+				"b":       b,
+				"numRead": numRead,
+				"result":  result,
+				"n":       n,
+			}).Infof("")
 			return 0, err
 		}
 		if n == 0 {
@@ -131,6 +139,7 @@ func ReadPacket(reader io.Reader) (*Packet, error) {
 
 	packet.PacketID, err = ReadVarInt(remainder)
 	if err != nil {
+		logrus.WithField("remainder", remainder.String()).Info("Failed to find PacketID")
 		return nil, err
 	}
 

pkg/server/connector.go

@@ -1,12 +1,13 @@
 package server
 
 import (
-	"net"
-	"github.com/sirupsen/logrus"
-	"github.com/itzg/mc-router/pkg/mcproto"
+	"bytes"
 	"context"
 	"io"
-	"bytes"
+	"net"
+
+	"github.com/itzg/mc-router/pkg/mcproto"
+	"github.com/sirupsen/logrus"
 )
 
 type IConnector interface {
@@ -136,9 +137,30 @@ func pumpConnections(ctx context.Context, frontendConn, backendConn net.Conn) {
 }
 
 func pumpFrames(incoming io.Reader, outgoing io.Writer, errors chan<- error, from, to string) {
-	amount, err := io.Copy(outgoing, incoming)
-	if err != nil {
-		errors <- err
+	for {
+		inspectionBuffer := new(bytes.Buffer)
+
+		inspectionReader := io.TeeReader(incoming, inspectionBuffer)
+
+		packet, err := mcproto.ReadPacket(inspectionReader)
+		if err != nil {
+			logrus.WithError(err).Error("Failed to read packet")
+			errors <- err
+			continue
+		}
+		amount, err := io.Copy(outgoing, inspectionBuffer)
+		if err != nil {
+			errors <- err
+			continue
+		}
+		logrus.WithFields(logrus.Fields{
+			"PacketID":     packet.PacketID,
+			"PacketLength": packet.Length,
+			"from":         from,
+			"to":           to,
+			"amount":       amount,
+		}).Info("Proxied packet")
 	}
-	logrus.WithField("amount", amount).Infof("Finished relay %s->%s", from, to)
+
+	logrus.Infof("Finished relay %s->%s", from, to)
 }