From 2b4dfdc56dcd0eee8f0f4625d4b0d90b0c6582b5 Mon Sep 17 00:00:00 2001
From: Jan Philipp Timme <jan.philipp@timme.it>
Date: Sat, 23 Nov 2019 20:23:05 +0100
Subject: [PATCH] Move decode logic into separate function

---
 main.go | 72 +++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 44 insertions(+), 28 deletions(-)

diff --git a/main.go b/main.go
index 32ea9b4..4bbd043 100644
--- a/main.go
+++ b/main.go
@@ -14,37 +14,53 @@ var (
 	logger logging.Logger
 )
 
-func handleMtaConnection(clientConnection *bufio.ReadWriter) {
+type milterPacket struct {
+	payloadLength uint32
+	message       string
+	payload       []byte
+}
+
+type smficOptineg struct {
+	version  uint32
+	actions  uint32
+	protocol uint32
+}
+
+func readRequestPacket(clientConnection *bufio.ReadWriter) (milterPacket, error) {
 	buf := make([]byte, 4096)
+	bytesRead, err := clientConnection.Read(buf)
+	if err != nil {
+		logger.Errorln("Error reading from clientConnection:", err.Error())
+		return milterPacket{}, err
+	}
+	logger.Infof("Read %d bytes from connection\n", bytesRead)
+	logger.Debugf("Hexdump of bytes read:\n%s", hex.Dump(buf[0:bytesRead]))
+	reqPacket := milterPacket{}
+	// First 4 Bytes will be some integer thing "length"
+	bytesReader := bytes.NewReader(buf[0:4])
+	err = binary.Read(bytesReader, binary.BigEndian, &reqPacket.payloadLength)
+	if err != nil {
+		logger.Errorln(err.Error())
+	}
+	logger.Debugf("Parsed length: %d\n", reqPacket.payloadLength)
+	// Next up is a character, indicating the milter command
+	logger.Debugf("Parsing command from byte: %X\n", buf[4])
+	reqPacket.message = string(buf[4])
+	logger.Debugf("Parsed packet command: %s\n", reqPacket.message)
+	// Last part is data with lenght len-1
+	reqPacket.payload = buf[5 : 5+reqPacket.payloadLength-1]
+	logger.Debugf("Hexdump of packet payload read:\n%s", hex.Dump(reqPacket.payload))
+	// That's it, we're done.
+	return reqPacket, nil
+}
+
+func handleMtaConnection(clientConnection *bufio.ReadWriter) {
 	for {
-		bytesRead, err := clientConnection.Read(buf)
-		if err != nil {
-			logger.Errorln("Error reading from clientConnection:", err.Error())
-			break
-		} else {
-			logger.Infof("Read %d bytes from connection\n", bytesRead)
-			logger.Debugf("Hexdump of bytes read:\n%s", hex.Dump(buf[0:bytesRead]))
-
-			// First 4 Bytes will be some integer thing "length"
-			// Let's parse that
-			var packetLength uint32
-			bytesReader := bytes.NewReader(buf[0:4])
-			err := binary.Read(bytesReader, binary.BigEndian, &packetLength)
-			if err != nil {
-				logger.Errorln(err.Error())
-			}
-			logger.Debugf("Parsed length: %d\n", packetLength)
-
-			// Next up is a character, indicating the milter command
-			logger.Debugf("Parsing command from byte: %X\n", buf[4])
-			command := string(buf[4])
-			logger.Debugf("Parsed packet command: %s\n", command)
-
-			// Last part is data with lenght len-1
-			data := make([]byte, packetLength)
-			data = buf[5 : 5+packetLength-1]
-			logger.Debugf("Hexdump of packet payload read:\n%s", hex.Dump(data))
+		request, _ := readRequestPacket(clientConnection)
 
+		if request.message == "O" {
+			responsePayload := smficOptineg{2, 0, 2}
+			//clientConnection.Write()
 		}
 	}
 }