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382 lines
22 KiB
Python
382 lines
22 KiB
Python
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# This module handles the IPv6 related functionality of the communication between charging station and car.
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#
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# It has the following sub-functionalities:
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# - IP.UDP.SDP for EvseMode: listen to requests from the car, and responding to them.
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# Eth --> IPv6 --> UDP --> V2GTP --> SDP
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# |
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# v
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# Eth <-- IPv6 <-- UDP <-- V2GTP <-- SDP
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#
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# - IP.UDP.SDP for PevMode: initiate an SDP request, and listen to the response of the charger
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# +---- Eth <-- IPv6 <-- UDP <-- V2GTP <-- SDP
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# homeplug
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# EVSE
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# homeplug
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# +---> Eth --> IPv6 --> UDP --> V2GTP --> SDP
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#
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# Abbreviations:
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# SECC: Supply Equipment Communication Controller. The "computer" of the charging station.
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# EVCC: Electric Vehicle Communication Controller. The "computer" of the vehicle.
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# SDP: SECC Discovery Protocol. The UDP based protocol to find out the IP address of the charging station.
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# SLAAC: Stateless auto address configuration (not SLAC!). A method to automatically set IPv6 address, based
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# on the 6 byte MAC address.
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from helpers import showAsHex, prettyHexMessage, prettyMac
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import udpChecksum
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class ipv6handler():
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def fillMac(self, macbytearray, position=6): # position 6 is the source MAC
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for i in range(0, 6):
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self.EthTxFrame[6+i] = macbytearray[i]
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def packResponseIntoEthernet(self, buffer):
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# packs the IP packet into an ethernet packet
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self.EthTxFrame = bytearray(len(buffer) + 6 + 6 + 2) # Ethernet header needs 14 bytes:
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# 6 bytes destination MAC
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# 6 bytes source MAC
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# 2 bytes EtherType
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for i in range(0, 6): # fill the destination MAC with the source MAC of the received package
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self.EthTxFrame[i] = self.myreceivebuffer[6+i]
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self.fillMac(self.ownMac) # bytes 6 to 11 are the source MAC
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self.EthTxFrame[12] = 0x86 # 86dd is IPv6
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self.EthTxFrame[13] = 0xdd
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for i in range(0, len(buffer)):
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self.EthTxFrame[14+i] = buffer[i]
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self.transmit(self.EthTxFrame)
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def packResponseIntoIp(self, buffer):
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# embeds the (SDP) response into the lower-layer-protocol: IP, Ethernet
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self.IpResponse = bytearray(len(buffer) + 8 + 16 + 16) # IP6 needs 40 bytes:
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# 4 bytes traffic class, flow
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# 2 bytes destination port
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# 2 bytes length (incl checksum)
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# 2 bytes checksum
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self.IpResponse[0] = 0x60 # traffic class, flow
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self.IpResponse[1] = 0
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self.IpResponse[2] = 0
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self.IpResponse[3] = 0
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plen = len(buffer) # length of the payload. Without headers.
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self.IpResponse[4] = plen >> 8
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self.IpResponse[5] = plen & 0xFF
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self.IpResponse[6] = 0x11 # next level protocol, 0x11 = UDP in this case
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self.IpResponse[7] = 0x0A # hop limit
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for i in range(0, 16):
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self.IpResponse[8+i] = self.SeccIp[i] # source IP address
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for i in range(0, 16):
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self.IpResponse[24+i] = self.EvccIp[i] # destination IP address
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for i in range(0, len(buffer)):
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self.IpResponse[40+i] = buffer[i]
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#showAsHex(self.IpResponse, "IP response ")
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self.packResponseIntoEthernet(self.IpResponse)
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def packResponseIntoUdp(self, buffer):
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# embeds the (SDP) response into the lower-layer-protocol: UDP
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self.UdpResponse = bytearray(len(buffer) + 8) # UDP needs 8 bytes:
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# 2 bytes source port
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# 2 bytes destination port
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# 2 bytes length (incl checksum)
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# 2 bytes checksum
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self.UdpResponse[0] = 15118 >> 8
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self.UdpResponse[1] = 15118 & 0xFF
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self.UdpResponse[2] = self.evccPort >> 8
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self.UdpResponse[3] = self.evccPort & 0xFF
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lenInclChecksum = len(buffer) + 8
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self.UdpResponse[4] = lenInclChecksum >> 8
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self.UdpResponse[5] = lenInclChecksum & 0xFF
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# checksum will be calculated afterwards
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self.UdpResponse[6] = 0
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self.UdpResponse[7] = 0
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for i in range(0, len(buffer)):
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self.UdpResponse[8+i] = buffer[i]
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#showAsHex(self.UdpResponse, "UDP response ")
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# The content of buffer is ready. We can calculate the checksum. see https://en.wikipedia.org/wiki/User_Datagram_Protocol
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checksum = udpChecksum.calculateUdpChecksumForIPv6(self.UdpResponse, self.SeccIp, self.EvccIp)
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self.UdpResponse[6] = checksum >> 8
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self.UdpResponse[7] = checksum & 0xFF
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self.packResponseIntoIp(self.UdpResponse)
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def sendSdpResponse(self):
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# SECC Discovery Response.
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# The response from the charger to the EV, which transfers the IPv6 address of the charger to the car.
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if (self.faultInjectionSuppressSdpResponse>0):
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print("Fault injection: SDP response suppressed")
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self.faultInjectionSuppressSdpResponse-=1
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return
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self.SdpPayload = bytearray(20) # SDP response has 20 bytes
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for i in range(0, 16):
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self.SdpPayload[i] = self.SeccIp[i] # 16 bytes IP address of the charger
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# Here the charger decides, on which port he will listen for the TCP communication.
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# We use port 15118, same as for the SDP. But also dynamically assigned port would be ok.
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# The alpitronics seems to use different ports on different chargers, e.g. 0xC7A7 and 0xC7A6.
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# The ABB Triple and ABB HPC are reporting port 0xD121, but in fact (also?) listening
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# to the port 15118.
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seccPort = 15118
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self.SdpPayload[16] = seccPort >> 8 # SECC port high byte.
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self.SdpPayload[17] = seccPort & 0xFF # SECC port low byte.
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self.SdpPayload[18] = 0x10 # security. We only support "no transport layer security, 0x10".
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self.SdpPayload[19] = 0x00 # transport protocol. We only support "TCP, 0x00".
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showAsHex(self.SdpPayload, "SDP payload ")
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# add the SDP header
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lenSdp = len(self.SdpPayload)
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self.V2Gframe = bytearray(lenSdp + 8) # V2GTP header needs 8 bytes:
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# 1 byte protocol version
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# 1 byte protocol version inverted
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# 2 bytes payload type
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# 4 byte payload length
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self.V2Gframe[0] = 0x01 # version
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self.V2Gframe[1] = 0xfe # version inverted
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self.V2Gframe[2] = 0x90 # payload type. 0x9001 is the SDP response message
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self.V2Gframe[3] = 0x01 #
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self.V2Gframe[4] = (lenSdp >> 24) & 0xff # length 4 byte.
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self.V2Gframe[5] = (lenSdp >> 16) & 0xff
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self.V2Gframe[6] = (lenSdp >> 8) & 0xff
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self.V2Gframe[7] = lenSdp & 0xff
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for i in range(0, lenSdp):
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self.V2Gframe[8+i] = self.SdpPayload[i]
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showAsHex(self.V2Gframe, "V2Gframe ")
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self.packResponseIntoUdp(self.V2Gframe)
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def evaluateUdpPayload(self):
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if ((self.destinationport == 15118) or (self.sourceport == 15118)): # port for the SECC
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if ((self.udpPayload[0]==0x01) and (self.udpPayload[1]==0xFE)): # protocol version 1 and inverted
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# it is a V2GTP message
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if (self.iAmEvse) and (self.destinationport == 15118):
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# if we are the charger, and it is a message from car to charger, lets save the cars IP for later use.
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self.EvccIp = self.sourceIp
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self.addressManager.setPevIp(self.EvccIp)
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showAsHex(self.udpPayload, "V2GTP ")
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if (self.destinationport == 15118): #if the destination is the charger,
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self.evccPort = self.sourceport #then the source is the vehicle
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v2gptPayloadType = self.udpPayload[2] * 256 + self.udpPayload[3]
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# 0x8001 EXI encoded V2G message (Will NOT come with UDP. Will come with TCP.)
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# 0x9000 SDP request message (SECC Discovery)
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# 0x9001 SDP response message (SECC response to the EVCC)
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if (v2gptPayloadType == 0x9000):
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v2gptPayloadLen = self.udpPayload[4] * 256 ** 3 + self.udpPayload[5] * 256 ** 2 + self.udpPayload[6] * 256 + self.udpPayload[7]
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if (v2gptPayloadLen == 2):
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# 2 is the only valid length for a SDP request.
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seccDiscoveryReqSecurity = self.udpPayload[8] # normally 0x10 for "no transport layer security". Or 0x00 for "TLS".
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seccDiscoveryReqTransportProtocol = self.udpPayload[9] # normally 0x00 for TCP
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if (seccDiscoveryReqSecurity!=0x10):
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print("seccDiscoveryReqSecurity " + str(seccDiscoveryReqSecurity) + " is not supported")
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else:
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if (seccDiscoveryReqTransportProtocol!=0x00):
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print("seccDiscoveryReqTransportProtocol " + str(seccDiscoveryReqTransportProtocol) + " is not supported")
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else:
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# This was a valid SDP request. Let's respond, if we are the charger.
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if (self.iAmEvse==1):
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print("Ok, this was a valid SDP request. We are the SECC. Sending SDP response.")
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self.callbackShowStatus("SDP 2", "evseState")
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self.sendSdpResponse()
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else:
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print("v2gptPayloadLen on SDP request is " + str(v2gptPayloadLen) + " not supported")
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return
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if (v2gptPayloadType == 0x9001):
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# it is a SDP response from the charger to the car
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if (self.iAmPev):
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v2gptPayloadLen = self.udpPayload[4] * 256 ** 3 + self.udpPayload[5] * 256 ** 2 + self.udpPayload[6] * 256 + self.udpPayload[7]
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if (v2gptPayloadLen == 20):
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# 20 is the only valid length for a SDP response.
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print("[PEV] Checkpoint203: Received SDP response")
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# at byte 8 of the UDP payload starts the IPv6 address of the charger.
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for i in range(0, 16):
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self.SeccIp[i] = self.udpPayload[8+i] # 16 bytes IP address of the charger
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# Extract the TCP port, on which the charger will listen:
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seccTcpPort = (self.udpPayload[8+16]*256) + self.udpPayload[8+16+1]
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self.addressManager.setSeccIp(self.SeccIp)
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self.addressManager.setSeccTcpPort(seccTcpPort)
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self.connMgr.SdpOk()
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return
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print("v2gptPayloadType " + hex(v2gptPayloadType) + " not supported")
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def initiateSdpRequest(self):
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if (self.iAmPev == 1):
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# We are the car. We want to find out the IPv6 address of the charger. We
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# send a SECC Discovery Request.
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# The payload is just two bytes: 10 00.
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# First step is, to pack this payload into a V2GTP frame.
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print("[PEV] initiating SDP request")
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self.v2gtpFrame = bytearray(8 + 2) # 8 byte header plus 2 bytes payload
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self.v2gtpFrame[0] = 0x01 # version
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self.v2gtpFrame[1] = 0xFE # version inverted
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self.v2gtpFrame[2] = 0x90 # 9000 means SDP request message
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self.v2gtpFrame[3] = 0x00
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self.v2gtpFrame[4] = 0x00
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self.v2gtpFrame[5] = 0x00
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self.v2gtpFrame[6] = 0x00
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self.v2gtpFrame[7] = 0x02 # payload size
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self.v2gtpFrame[8] = 0x10 # payload
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self.v2gtpFrame[9] = 0x00 # payload
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# Second step: pack this into an UDP frame.
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self.packRequestIntoUdp(self.v2gtpFrame)
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def packRequestIntoUdp(self, buffer):
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# embeds the (SDP) request into the lower-layer-protocol: UDP
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# Reference: wireshark trace of the ioniq car
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self.UdpRequest = bytearray(len(buffer) + 8) # UDP header needs 8 bytes:
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# 2 bytes source port
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# 2 bytes destination port
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# 2 bytes length (incl checksum)
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# 2 bytes checksum
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self.pevPort = 50032 # "random" port. Todo: Do we need to ask the OS for a unique number, to avoid collision with existing port?
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self.UdpRequest[0] = self.pevPort >> 8
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self.UdpRequest[1] = self.pevPort & 0xFF
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self.UdpRequest[2] = 15118 >> 8
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self.UdpRequest[3] = 15118 & 0xFF
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lenInclChecksum = len(buffer) + 8
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self.UdpRequest[4] = lenInclChecksum >> 8
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self.UdpRequest[5] = lenInclChecksum & 0xFF
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# checksum will be calculated afterwards
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self.UdpRequest[6] = 0
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self.UdpRequest[7] = 0
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for i in range(0, len(buffer)):
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self.UdpRequest[8+i] = buffer[i]
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#showAsHex(self.UdpRequest, "UDP request ")
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self.broadcastIPv6 = [ 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]
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# The content of buffer is ready. We can calculate the checksum. see https://en.wikipedia.org/wiki/User_Datagram_Protocol
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checksum = udpChecksum.calculateUdpChecksumForIPv6(self.UdpRequest, self.EvccIp, self.broadcastIPv6)
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self.UdpRequest[6] = checksum >> 8
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self.UdpRequest[7] = checksum & 0xFF
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self.packRequestIntoIp(self.UdpRequest)
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def packRequestIntoIp(self, buffer):
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# embeds the (SDP) request into the lower-layer-protocol: IP, Ethernet
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self.IpRequest = bytearray(len(buffer) + 8 + 16 + 16) # IP6 header needs 40 bytes:
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# 4 bytes traffic class, flow
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# 2 bytes destination port
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# 2 bytes length (incl checksum)
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# 2 bytes checksum
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self.IpRequest[0] = 0x60 # traffic class, flow
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self.IpRequest[1] = 0
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self.IpRequest[2] = 0
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self.IpRequest[3] = 0
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plen = len(buffer) # length of the payload. Without headers.
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self.IpRequest[4] = plen >> 8
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self.IpRequest[5] = plen & 0xFF
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self.IpRequest[6] = 0x11 # next level protocol, 0x11 = UDP in this case
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self.IpRequest[7] = 0x0A # hop limit
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# We are the PEV. So the EvccIp is our own link-local IP address.
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self.EvccIp = self.addressManager.getLinkLocalIpv6Address("bytearray")
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for i in range(0, 16):
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self.IpRequest[8+i] = self.EvccIp[i] # source IP address
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for i in range(0, 16):
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self.IpRequest[24+i] = self.broadcastIPv6[i] # destination IP address
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for i in range(0, len(buffer)):
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self.IpRequest[40+i] = buffer[i]
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#showAsHex(self.IpRequest, "IpRequest ")
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self.packRequestIntoEthernet(self.IpRequest)
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def packRequestIntoEthernet(self, buffer):
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# packs the IP packet into an ethernet packet
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self.EthTxFrame = bytearray(len(buffer) + 6 + 6 + 2) # Ethernet header needs 14 bytes:
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# 6 bytes destination MAC
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# 6 bytes source MAC
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# 2 bytes EtherType
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# fill the destination MAC with the IPv6 multicast
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self.EthTxFrame[0] = 0x33
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self.EthTxFrame[1] = 0x33
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self.EthTxFrame[2] = 0x00
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self.EthTxFrame[3] = 0x00
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self.EthTxFrame[4] = 0x00
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self.EthTxFrame[5] = 0x01
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self.fillMac(self.ownMac) # bytes 6 to 11 are the source MAC
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self.EthTxFrame[12] = 0x86 # 86dd is IPv6
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self.EthTxFrame[13] = 0xdd
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for i in range(0, len(buffer)):
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self.EthTxFrame[14+i] = buffer[i]
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self.transmit(self.EthTxFrame)
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def enterPevMode(self):
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self.iAmEvse = 0 # not emulating a charging station
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self.iAmPev = 1 # emulating a vehicle
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def enterEvseMode(self):
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self.iAmEvse = 1 # emulating a charging station
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self.iAmPev = 0 # not emulating a vehicle
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# If we are an charger, we need to support the SDP, which requires to know our IPv6 adrress.
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self.SeccIp = self.addressManager.getLinkLocalIpv6Address("bytearray")
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def enterListenMode(self):
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self.iAmEvse = 0 # not emulating a charging station
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self.iAmPev = 0 # not emulating a vehicle
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def evaluateV2GTP(self):
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# We sniffed a V2GTP frame via TCP. This should contain an EXI encoded payload.
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v2gptPayloadType = self.v2gframe[2] * 256 + self.v2gframe[3]
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# 0x8001 EXI encoded V2G message
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if (v2gptPayloadType == 0x8001):
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self.ExiPacket = self.v2gframe[8:] # the exi payload, without the 8 bytes V2GTP header
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s = "[SNIFFER] EXI from " + str(self.tcpsourceport) + " to " + str(self.tcpdestinationport) + " " + prettyHexMessage(self.ExiPacket)
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print(s)
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# print(s, file=self.exiLogFile)
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# Todo: further process the EXI packet. E.g. write it into file for offline analysis.
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# And send it to decoder.
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def evaluateTcpPacket(self):
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# We received a TCP packet. We do NOT want to make real TCP here (the OS will do it much better). We
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# just want to listen to the conversation of two others, and extract what we hear.
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self.tcpsourceport = self.myreceivebuffer[54] * 256 + self.myreceivebuffer[55]
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self.tcpdestinationport = self.myreceivebuffer[56] * 256 + self.myreceivebuffer[57]
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if (True): # we do not check port, because the TCP port is variable. (self.tcpsourceport == 15118) or (self.tcpdestinationport == 15118))
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if (len(self.myreceivebuffer)>=74+9): # 74 is the TCP without any data. A V2GTP has 8 bytes header, plus at least 1 payload byte.
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startOfV2gtp = 74 # the index of the first V2GTP byte in the ethernet buffer
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if ((self.myreceivebuffer[startOfV2gtp] == 0x01) and (self.myreceivebuffer[startOfV2gtp+1] == 0xFE)):
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# version and inverted version of the V2GTP are fine -> it is a V2G TP frame.
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self.v2gframe = self.myreceivebuffer[startOfV2gtp:]
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self.evaluateV2GTP()
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def evaluateReceivedPacket(self, pkt):
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# The evaluation function for received ipv6 packages.
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if (len(pkt)>60):
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self.myreceivebuffer = pkt
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# extract the source ipv6 address
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self.sourceIp = bytearray(16)
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for i in range(0, 16):
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self.sourceIp[i] = self.myreceivebuffer[22+i]
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self.nextheader = self.myreceivebuffer[20]
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if (self.nextheader == 0x11): # it is an UDP frame
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self.sourceport = self.myreceivebuffer[54] * 256 + self.myreceivebuffer[55]
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self.destinationport = self.myreceivebuffer[56] * 256 + self.myreceivebuffer[57]
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self.udplen = self.myreceivebuffer[58] * 256 + self.myreceivebuffer[59]
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self.udpsum = self.myreceivebuffer[60] * 256 + self.myreceivebuffer[61]
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# udplen is including 8 bytes header at the begin
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if (self.udplen>8):
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self.udpPayload = bytearray(self.udplen-8)
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# print("self.udplen=" + str(self.udplen))
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# print("self.myreceivebuffer len=" + str(len(self.myreceivebuffer)))
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for i in range(0, self.udplen-8):
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#print("index " + str(i) + " " + hex(self.myreceivebuffer[62+i]))
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self.udpPayload[i] = self.myreceivebuffer[62+i]
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self.evaluateUdpPayload()
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if (self.nextheader == 0x06): # it is an TCP frame
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self.evaluateTcpPacket()
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def __init__(self, transmitCallback, addressManager, connMgr, callbackShowStatus):
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self.iAmEvse = 0
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self.iAmPev = 0
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self.transmit = transmitCallback
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self.addressManager = addressManager
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self.connMgr = connMgr
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self.callbackShowStatus = callbackShowStatus
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#self.exiLogFile = open('SnifferExiLog.txt', 'w')
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# 16 bytes, a default IPv6 address for the charging station
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# self.SeccIp = [ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0x06, 0xaa, 0xaa, 0xff, 0xfe, 0, 0xaa, 0xaa ]
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# fe80::e0ad:99ac:52eb:85d3 is the Win10 laptop
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# self.SeccIp = [ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0xe0, 0xad, 0x99, 0xac, 0x52, 0xeb, 0x85, 0xd3 ]
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# just a default for the chargers IP, will be filled later with the correct value from SDP
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self.SeccIp = bytearray(16)
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# 16 bytes, a default IPv6 address for the vehicle
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# Just a default, will be overwritten later:
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self.EvccIp = [ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0x06, 0x65, 0x65, 0xff, 0xfe, 0, 0x64, 0xC3 ]
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self.ownMac = self.addressManager.getLocalMacAddress()
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self.faultInjectionSuppressSdpResponse = 0 # can be set to >0 for fault injection. Number of "lost" SDP responses.
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print("pyPlcIpv6 started with ownMac " + prettyMac(self.ownMac))
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