added comments. improved logging on PEV side.

fsmPev.py

@@ -46,6 +46,7 @@ class fsmPev():
     def stateFunctionInitialized(self):
         if (self.Tcp.isConnected):
             # we just use the initial request message from the Ioniq. It contains one entry: DIN.
+            self.addToTrace("Sending the initial SupportedApplicationProtocolReq")
             self.Tcp.transmit(addV2GTPHeader(exiHexToByteArray(exiHexDemoSupportedApplicationProtocolRequestIoniq)))
             self.enterState(stateWaitForSupportedApplicationProtocolResponse)
         
@@ -58,6 +59,7 @@ class fsmPev():
             self.addToTrace(strConverterResult)
             if (strConverterResult.find("supportedAppProtocolRes")>0):
                 # todo: check the request content, and fill response parameters
+                self.addToTrace("Will send SessionSetupReq")
                 msg = addV2GTPHeader(exiEncode("EDA")) # EDA for Encode, Din, SessionSetupReq
                 self.addToTrace("responding " + prettyHexMessage(msg))
                 self.Tcp.transmit(msg)
@@ -77,10 +79,11 @@ class fsmPev():
                 try:
                     y = json.loads(strConverterResult)
                     strSessionId = y["header.SessionID"]
-                    self.addToTrace("[PEV] The Evse decided for SessionId " + strSessionId)
+                    self.addToTrace("The Evse decided for SessionId " + strSessionId)
                     self.sessionId = strSessionId
                 except:
                     self.addToTrace("ERROR: Could not decode the sessionID")
+                self.addToTrace("Will send ServiceDiscoveryReq")
                 msg = addV2GTPHeader(exiEncode("EDB_"+self.sessionId)) # EDB for Encode, Din, ServiceDiscoveryRequest
                 self.addToTrace("responding " + prettyHexMessage(msg))
                 self.Tcp.transmit(msg)
@@ -97,6 +100,7 @@ class fsmPev():
             self.addToTrace(strConverterResult)
             if (strConverterResult.find("ServiceDiscoveryRes")>0):
                 # todo: check the request content, and fill response parameters
+                self.addToTrace("Will send ServicePaymentSelectionReq")
                 msg = addV2GTPHeader(exiEncode("EDC_"+self.sessionId)) # EDC for Encode, Din, ServicePaymentSelection
                 self.addToTrace("responding " + prettyHexMessage(msg))
                 self.Tcp.transmit(msg)
@@ -113,6 +117,7 @@ class fsmPev():
             self.addToTrace(strConverterResult)
             if (strConverterResult.find("ServicePaymentSelectionRes")>0):
                 # todo: check the request content, and fill response parameters
+                self.addToTrace("Will send ChargeParameterDiscoveryReq")
                 msg = addV2GTPHeader(exiEncode("EDE_"+self.sessionId)) # EDE for Encode, Din, ChargeParameterDiscovery. We ignore Authorization, not specified in DIN.
                 self.addToTrace("responding " + prettyHexMessage(msg))
                 self.Tcp.transmit(msg)
@@ -129,6 +134,7 @@ class fsmPev():
             self.addToTrace(strConverterResult)
             if (strConverterResult.find("ChargeParameterDiscoveryRes")>0):
                 # todo: check the request content, and fill response parameters
+                self.addToTrace("Will send CableCheckReq")
                 msg = addV2GTPHeader(exiEncode("EDF_"+self.sessionId)) # EDF for Encode, Din, CableCheck
                 self.addToTrace("responding " + prettyHexMessage(msg))
                 self.Tcp.transmit(msg)
@@ -156,12 +162,15 @@ class fsmPev():
                 # 1) The charger says "cable check is finished and cable ok", by setting ResponseCode=OK and EVSEProcessing=Finished.
                 # 2) Else: The charger says "need more time or cable not ok". In this case, we just run into timeout and start from the beginning.
                 if ((strEVSEProcessing==dinEVSEProcessingType_Finished) and (strResponseCode=="OK")):
+                    self.addToTrace("The EVSE says that the CableCheck is finished and ok.")
+                    self.addToTrace("Will send PreChargeReq")
                     msg = addV2GTPHeader(exiEncode("EDG_"+self.sessionId)) # EDG for Encode, Din, PreCharge
                     self.addToTrace("responding " + prettyHexMessage(msg))
                     self.Tcp.transmit(msg)
                     self.enterState(stateWaitForPreChargeResponse)
                 else:
                     # cable check not yet finished or finished with bad result -> try again
+                    self.addToTrace("Will again send CableCheckReq")
                     msg = addV2GTPHeader(exiEncode("EDF_"+self.sessionId)) # EDF for Encode, Din, CableCheck
                     self.addToTrace("responding " + prettyHexMessage(msg))
                     self.Tcp.transmit(msg)

udplog.py

@@ -10,12 +10,17 @@ class udplog():
             
                           
     def log(self, s):
+        # The frame format follows the Syslog protocol, https://en.wikipedia.org/wiki/Syslog
+        # Level consists of
+        #  Facility = 1 = "user"
+        #  Severity = 7 = "debug"
         strLevel="<15>"
+        # The String to be logged. Terminated by 00.
         strMessage=s+"\0"
       
-        lenPayLoad = 4 + len(strMessage)
+        lenPayLoad = 4 + len(strMessage) # length of level is 4
         
-        buffer=bytearray(lenPayLoad+28)
+        buffer=bytearray(lenPayLoad+28) # prepare the IPv4 buffer. Including 28 bytes IP header.
         # syslog level (4 characters)
         for i in range(0, len(strLevel)):
             buffer[28+i] = ord(strLevel[i])
@@ -41,8 +46,8 @@ class udplog():
         # source ip 4 bytes
         buffer[12] = 192 # does this really matter?
         buffer[13] = 168
-        buffer[14] = 2
+        buffer[14] = self.ownMac[4] # quick&dirty: we just fill the last two bytes of the MAC here.
-        buffer[15] = 222
+        buffer[15] = self.ownMac[5] #
         # destination ip 4 bytes: broadcast
         buffer[16] = 0xff
         buffer[17] = 0xff
@@ -51,13 +56,13 @@ class udplog():
         # source port
         buffer[20] = 0xff
         buffer[21] = 0x95
-        # destination port
+        # destination port. 0x0202 = 514 = the official Syslog UDP port
         buffer[22] = 0x02
         buffer[23] = 0x02
         udplen = lenPayLoad + 8 # payload plus 8 byte udp header
         buffer[24] = udplen >> 8
         buffer[25] = (udplen & 0xff)
-        udpchecksum = 0
+        udpchecksum = 0 # checksum 0 has the special meaning: no checksum. Receiver ignores it.
         buffer[26] = udpchecksum >> 8
         buffer[27] = (udpchecksum & 0xff)
         
@@ -78,9 +83,9 @@ class udplog():
         self.fillMac(self.ownMac) # bytes 6 to 11 are the source MAC
         self.EthTxFrame[12] = 0x08 # 0800 is IPv4
         self.EthTxFrame[13] = 0x00
-        for i in range(0, len(buffer)):
+        for i in range(0, len(buffer)): # copy the IPv4 buffer content into the Ethernet buffer
             self.EthTxFrame[14+i] = buffer[i]
-        self.transmit(self.EthTxFrame)
+        self.transmit(self.EthTxFrame) # and finally transmit the Ethernet frame
 
                         
     def __init__(self, transmitCallback, addressManager):