From b99a0665f0407604757fe35b105c7f93cf4ce915 Mon Sep 17 00:00:00 2001
From: uhi22 <uhi@hnng.de>
Date: Fri, 21 Oct 2022 21:27:39 +0200
Subject: [PATCH] playground for sockets and EXI

---
 demo_V2GTP.py  | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++
 demo_socket.py | 43 +++++++++++++++++++++++++++++
 2 files changed, 118 insertions(+)
 create mode 100644 demo_V2GTP.py
 create mode 100644 demo_socket.py

diff --git a/demo_V2GTP.py b/demo_V2GTP.py
new file mode 100644
index 0000000..acf115c
--- /dev/null
+++ b/demo_V2GTP.py
@@ -0,0 +1,75 @@
+
+
+# EXI is specified in w3.org/TR/exi
+# To decode and encode, we can use this Decoder/Encoder: https://github.com/FlUxIuS/V2Gdecoder
+#
+# https://github.com/FlUxIuS/V2Gdecoder/releases
+# Install java from https://www.java.com/de/download/manual.jsp
+#
+# C:\>java -version
+# java version "1.8.0_351"
+# Java(TM) SE Runtime Environment (build 1.8.0_351-b10)
+# Java HotSpot(TM) Client VM (build 25.351-b10, mixed mode, sharing)
+# C:\>
+#
+# In wireshark: Copy as hex stream
+# 01fe8001000000228000dbab9371d3234b71d1b981899189d191818991d26b9b3a232b30020000040040
+# remove the 8 bytes V2GTP header
+# 8000dbab9371d3234b71d1b981899189d191818991d26b9b3a232b30020000040040
+#
+# java -jar V2Gdecoder.jar -e -s 8000dbab9371d3234b71d1b981899189d191818991d26b9b3a232b30020000040040
+# ERROR:  'Premature EOS found while reading data.'
+# <?xml version="1.0" encoding="UTF-8"?><ns4:supportedAppProtocolReq xmlns:ns4="urn:iso:15118:2:2010:AppProtocol" 
+# xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns3="http://www.w3.org/2001/XMLSchema">
+# <AppProtocol>
+#  <ProtocolNamespace>urn:din:70121:2012:MsgDef</ProtocolNamespace>
+#  <VersionNumberMajor>2</VersionNumberMajor>
+#  <VersionNumberMinor>0</VersionNumberMinor>
+#  <SchemaID>1</SchemaID>
+#  <Priority>1</Priority>
+# </AppProtocol>
+# </ns4:supportedAppProtocolReq>
+#
+#
+#
+#
+
+from helpers import showAsHex
+
+# Example: This is the first message from the EVCC.
+#  Means: It is an supportedAppProtocolReq message. It provides a list of charging protocols supported by the EVCC.
+#
+# 
+v2gframe = [
+0x01, 0xfe,
+0x80, 0x01,
+0x00, 0x00, 0x00, 0x22,
+0x80, 0x00, 0xdb, 0xab, 0x93, 0x71, 0xd3, 0x23, 0x4b, 0x71, 0xd1, 0xb9, 0x81, 0x89,
+0x91, 0x89, 0xd1, 0x91, 0x81, 0x89, 0x91, 0xd2, 0x6b, 0x9b, 0x3a, 0x23, 0x2b, 0x30, 0x02, 0x00,
+0x00, 0x04, 0x00, 0x40 ]
+
+
+if (len(v2gframe)<9):
+    print("size too small")
+else:
+    if ((v2gframe[0]!=0x01) or (v2gframe[1]!=0xFE)):
+        print("wrong V2GTP version")
+    else:
+        if ((v2gframe[2]!=0x80) or (v2gframe[3]!=0x01)):
+            print("wrong payload type, expecting 0x8001 EXI")
+        else:
+            exiLen = (v2gframe[4]<<24) + (v2gframe[5]<<16) + (v2gframe[6]<<8) + v2gframe[7]
+            print("exiLen=" + str(exiLen))
+            if (exiLen+8 != len(v2gframe)):
+                print("exiLen does not match actual frame size")
+            else:
+                print("header ok")
+                exiframe = bytearray(exiLen)
+                exiframe = v2gframe[8:]
+                showAsHex(exiframe, "exiframe ")
+                # Header:
+                # 80 upper two bits: distinguishing bits 1 0
+                #    presenceBitForExiOptions  0 means "no options"
+                #    five bits version information: 0 0 0 0 0 means "final version 1"
+                #
+                # 00 DB AB 93 71 D3 23 4B
diff --git a/demo_socket.py b/demo_socket.py
new file mode 100644
index 0000000..08a019a
--- /dev/null
+++ b/demo_socket.py
@@ -0,0 +1,43 @@
+
+# explanation of socket handling:
+# https://realpython.com/python-sockets/
+#
+
+import socket
+import select
+
+
+
+print("Press Ctrl-Break for aborting")
+
+TCP_IP = 'fe80::e0ad:99ac:52eb:85d3'
+TCP_PORT = 15118 # The port for CCS
+BUFFER_SIZE = 1024  # Normally 1024
+
+ourSocket = socket.socket(socket.AF_INET6, socket.SOCK_STREAM, 0)
+ourSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+
+ourSocket.bind((TCP_IP, TCP_PORT))
+ourSocket.listen(1)
+print("listening on port " + str(TCP_PORT))
+
+# example from https://stackoverflow.com/questions/5308080/python-socket-accept-nonblocking
+read_list = [ourSocket]
+while True:
+    # The select() function will block until one of the socket states has changed.
+    # We specify a timeout, to be able to run it in the main loop.
+    print("before select")
+    readable, writable, errored = select.select(read_list, [], [], 0.5)
+    for s in readable:
+        if s is ourSocket:
+            client_socket, address = ourSocket.accept()
+            read_list.append(client_socket)
+            print("Connection from", address)
+        else:
+            data = s.recv(1024)
+            if data:
+                print("received data:", data)
+            else:
+                print("connection closed")
+                s.close()
+                read_list.remove(s)
\ No newline at end of file