Added basic ftp and http support

Author: shadowy-pycoder

layers/ftp.go

@@ -1,14 +1,19 @@
 package layers
 
-// https://mavlink.io/zh/services/ftp.html
-// port 21 port 20
-type FTPMessage struct{}
+import "fmt"
+
+type FTPMessage struct {
+	payload string
+}
 
 func (f *FTPMessage) String() string {
-	return ""
+	return fmt.Sprintf(`FTP Message:
+%s
+`, f.payload)
 }
 
 func (f *FTPMessage) Parse(data []byte) error {
+	f.payload = bytesToStr(data)
 	return nil
 }
 

layers/http.go

@@ -1,14 +1,21 @@
 package layers
 
+import "fmt"
+
 // https://developer.mozilla.org/en-US/docs/Web/HTTP/Messages
 // port 80
-type HTTPMessage struct{}
+type HTTPMessage struct {
+	payload string
+}
 
 func (h *HTTPMessage) String() string {
-	return ""
+	return fmt.Sprintf(`HTTP Message:
+%s
+`, h.payload)
 }
 
 func (h *HTTPMessage) Parse(data []byte) error {
+	h.payload = bytesToStr(data)
 	return nil
 }
 

layers/layers.go

@@ -15,7 +15,7 @@ var LayerMap = map[string]Layer{
 	"ICMP":   &ICMPSegment{},
 	"ICMPv6": &ICMPv6Segment{},
 	"DNS":    &DNSMessage{},
-	"FTP":    &DNSMessage{},
+	"FTP":    &FTPMessage{},
 	"HTTP":   &HTTPMessage{},
 	"SNMP":   &SNMPMessage{},
 	"SSH":    &SSHMessage{},
@@ -49,6 +49,6 @@ func nextAppLayer(src, dst uint16) string {
 	return layer
 }
 
-func bytesToStr(myBytes []byte) string {
-	return unsafe.String(unsafe.SliceData(myBytes), len(myBytes))
+func bytesToStr(b []byte) string {
+	return unsafe.String(unsafe.SliceData(b), len(b))
 }

layers/snmp.go

@@ -1,6 +1,7 @@
 package layers
 
 // https://www.ranecommercial.com/legacy/pdf/ranenotes/SNMP_Simple_Network_Management_Protocol.pdf
+// https://wiki.wireshark.org/SNMP
 // port 161, 162
 type SNMPMessage struct{}
 

mshark.go

@@ -81,7 +81,7 @@ func (mw *Writer) WritePacket(timestamp time.Time, data []byte) error {
 	mw.printPacket(next, layerNum)
 	for {
 		name, data := next.NextLayer()
-		if name == "" {
+		if name == "" || len(data) == 0 {
 			return nil
 		}
 		next = layers.LayerMap[name]