Made NextLayer method shorter for those that do not have next layer

Author: shadowy-pycoder

layers/arp.go

@@ -100,9 +100,7 @@ func (ap *ARPPacket) Parse(data []byte) error {
 	return nil
 }
 
-func (ap *ARPPacket) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (ap *ARPPacket) NextLayer() (layer string, payload []byte) { return }
 
 func ptypedesc(pt uint16) string {
 	var proto string

layers/dns.go

@@ -268,9 +268,7 @@ func (d *DNSMessage) Parse(data []byte) error {
 	return nil
 }
 
-func (d *DNSMessage) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (d *DNSMessage) NextLayer() (layer string, payload []byte) { return }
 
 func (d *DNSMessage) printRecords() string {
 	var sb strings.Builder

layers/ftp.go

@@ -37,6 +37,4 @@ func (f *FTPMessage) Parse(data []byte) error {
 	return nil
 }
 
-func (f *FTPMessage) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (f *FTPMessage) NextLayer() (layer string, payload []byte) { return }

layers/http.go

@@ -56,6 +56,4 @@ func (h *HTTPMessage) Parse(data []byte) error {
 	return nil
 }
 
-func (h *HTTPMessage) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (h *HTTPMessage) NextLayer() (layer string, payload []byte) { return }

layers/icmp.go

@@ -65,9 +65,7 @@ func (i *ICMPSegment) Parse(data []byte) error {
 	i.TypeDesc, i.CodeDesc = i.typecode()
 	return nil
 }
-func (i *ICMPSegment) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (i *ICMPSegment) NextLayer() (layer string, payload []byte) { return }
 
 func (i *ICMPSegment) typecode() (string, string) {
 	// https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol

layers/icmpv6.go

@@ -68,9 +68,7 @@ func (i *ICMPv6Segment) Parse(data []byte) error {
 	return nil
 }
 
-func (i *ICMPv6Segment) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (i *ICMPv6Segment) NextLayer() (layer string, payload []byte) { return }
 
 func (i *ICMPv6Segment) typecode() (string, string) {
 	// https://en.wikipedia.org/wiki/ICMPv6

layers/layers.go

@@ -39,7 +39,7 @@ var (
 type Layer interface {
 	fmt.Stringer
 	Parse(data []byte) error
-	NextLayer() (name string, payload []byte)
+	NextLayer() (layer string, payload []byte)
 	Summary() string
 }
 

layers/snmp.go

@@ -22,6 +22,4 @@ func (s *SNMPMessage) Parse(data []byte) error {
 	return nil
 }
 
-func (s *SNMPMessage) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (s *SNMPMessage) NextLayer() (layer string, payload []byte) { return }

layers/ssh.go

@@ -119,9 +119,7 @@ func (s *SSHMessage) Parse(data []byte) error {
 	return nil
 }
 
-func (s *SSHMessage) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (s *SSHMessage) NextLayer() (layer string, payload []byte) { return }
 
 // https://www.iana.org/assignments/ssh-parameters/ssh-parameters.xhtml
 func mtypedesc(mtype uint8) string {

layers/tls.go

@@ -115,9 +115,7 @@ func (t *TLSMessage) Parse(data []byte) error {
 	return nil
 }
 
-func (t *TLSMessage) NextLayer() (string, []byte) {
-	return "", nil
-}
+func (t *TLSMessage) NextLayer() (layer string, payload []byte) { return }
 
 func ctdesc(ct uint8) string {
 	// https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-5