Improve packet parsing

firewall/interception/nfq/nfq.go

@@ -179,11 +179,13 @@ func (q *Queue) packetHandler(ctx context.Context) func(nfqueue.Attribute) int {
 			verdictPending: abool.New(),
 		}
 
-		if attrs.Payload != nil {
-			pkt.Payload = *attrs.Payload
+		if attrs.Payload == nil {
+			// There is not payload.
+			log.Warningf("nfqueue: packet #%s has no payload", pkt.pktID)
+			return 0
 		}
 
-		if err := pmpacket.Parse(pkt.Payload, pkt.Info()); err != nil {
+		if err := pmpacket.Parse(*attrs.Payload, &pkt.Base); err != nil {
 			log.Warningf("nfqueue: failed to parse payload: %s", err)
 			_ = pkt.Drop()
 			return 0

firewall/interception/nfq/packet.go

@@ -65,6 +65,11 @@ func (pkt *packet) ID() string {
 	return fmt.Sprintf("pkt:%d qid:%d", pkt.pktID, pkt.queue.id)
 }
 
+// LoadPacketData does nothing on Linux, as data is always fully parsed.
+func (pkt *packet) LoadPacketData() error {
+	return nil
+}
+
 // TODO(ppacher): revisit the following behavior:
 // 		The legacy implementation of nfqueue (and the interception) module
 // 		always accept a packet but may mark it so that a subsequent rule in

firewall/interception/windowskext/kext.go

@@ -230,6 +230,7 @@ func GetPayload(packetID uint32, packetSize uint32) ([]byte, error) {
 	if packetSize < uint32(len(buf)) {
 		return buf[:packetSize], nil
 	}
+
 	return buf, nil
 }
 

firewall/interception/windowskext/packet.go

@@ -24,7 +24,7 @@ type Packet struct {
 }
 
 // GetPayload returns the full raw packet.
-func (pkt *Packet) GetPayload() ([]byte, error) {
+func (pkt *Packet) LoadPacketData() error {
 	pkt.lock.Lock()
 	defer pkt.lock.Unlock()
 
@@ -33,17 +33,21 @@ func (pkt *Packet) GetPayload() ([]byte, error) {
 
 		payload, err := GetPayload(pkt.verdictRequest.id, pkt.verdictRequest.packetSize)
 		if err != nil {
-			log.Tracer(pkt.Ctx()).Warningf("windowskext: failed to load payload %s", err)
-			log.Errorf("windowskext: failed to load payload %s", err)
-			return nil, packet.ErrFailedToLoadPayload
+			log.Tracer(pkt.Ctx()).Warningf("windowskext: failed to load payload: %s", err)
+			return packet.ErrFailedToLoadPayload
+		}
+
+		err = packet.Parse(payload, &pkt.Base)
+		if err != nil {
+			log.Tracer(pkt.Ctx()).Warningf("windowskext: failed to parse payload: %s", err)
+			return packet.ErrFailedToLoadPayload
 		}
-		pkt.Payload = payload
 	}
 
-	if len(pkt.Payload) == 0 {
-		return nil, packet.ErrFailedToLoadPayload
+	if len(pkt.Raw()) == 0 {
+		return packet.ErrFailedToLoadPayload
 	}
-	return pkt.Payload, nil
+	return nil
 }
 
 // Accept accepts the packet.