Added Modbus TCP proxy

docs/utilities.rst

@@ -2,6 +2,22 @@
 Utilities
 ===================
 
+Solarman TCP Proxy
+^^^^^^^^^^^^^^^^^^
+
+.. code-block:: console
+
+    user@host:~ $ solarman-tcp-proxy -h
+    usage: solarman tcp proxy [-h] [-b BIND] [-p PORT] -l LOGGER -s SERIAL
+
+    A Modbus TCP Proxy for Solarman loggers
+
+    options:
+      -h, --help           show this help message and exit
+      -b, --bind BIND      The address to listen on
+      -p, --port PORT      The TCP port to listen on
+      -l, --logger LOGGER  The IP address of the logger
+      -s, --serial SERIAL  The serial number of the logger
 
 Solarman RTU Proxy
 ^^^^^^^^^^^^^^^^^^

utils/solarman_tcp_proxy.py

@@ -0,0 +1,119 @@
+"""Modbus TCP to Solarman proxy
+
+Can be used with Home Assistant's native Modbus integration using config below:
+
+- name: "solarman-modbus-proxy"
+  type: tcp
+  host: 192.168.1.20
+  port: 1502
+  delay: 3
+  retry_on_empty: true
+  sensors:
+    [...]
+
+"""
+
+import argparse
+import asyncio
+import struct
+from functools import partial
+from umodbus.client.serial.redundancy_check import get_crc
+from pysolarmanv5 import PySolarmanV5Async
+
+
+async def handle_client(
+    reader: asyncio.StreamReader,
+    writer: asyncio.StreamWriter,
+    logger_address: str,
+    logger_serial: int,
+):
+    solarmanv5 = PySolarmanV5Async(
+        logger_address, logger_serial, verbose=True, auto_reconnect=True
+    )
+    await solarmanv5.connect()
+
+    addr = writer.get_extra_info("peername")
+
+    print(f"{addr}: New connection")
+
+    try:
+        while True:
+            # Convert TCP to RTU
+            header = await reader.readexactly(6)
+            if not header:
+                break
+
+            trans_id, proto_id, length = struct.unpack(">HHH", header)
+            unit_id = await reader.readexactly(1)
+            pdu = await reader.readexactly(length - 1)  # length includes unit_id
+
+            slave_id = b"\x01"
+            modbus_rtu = slave_id + pdu + get_crc(slave_id + pdu)
+
+            try:
+                # Convert RTU back to TCP
+                reply_rtu = await solarmanv5.send_raw_modbus_frame(modbus_rtu)
+
+                slave_id_reply = reply_rtu[0:1]
+                pdu_reply = reply_rtu[1:-2]
+                crc_reply = reply_rtu[-2:]
+
+                mbap = struct.pack(">HHH", trans_id, 0, len(pdu_reply) + 1)
+                reply_tcp = mbap + unit_id + pdu_reply
+
+                writer.write(reply_tcp)
+            except:
+                pass
+
+        await writer.drain()
+    except OSError:
+        # https://github.com/python/cpython/issues/83037
+        pass
+
+    print(f"{addr}: Connection closed")
+    await solarmanv5.disconnect()
+
+
+async def run_proxy(
+    bind_address: str, port: int, logger_address: str, logger_serial: int
+):
+    server = await asyncio.start_server(
+        partial(
+            handle_client, logger_address=logger_address, logger_serial=logger_serial
+        ),
+        bind_address,
+        port,
+    )
+    async with server:
+        print(f"Listening on {bind_address}:{port}")
+        await server.serve_forever()
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        prog="solarman rtu proxy",
+        description="A Modbus RTU over TCP Proxy for Solarman loggers",
+    )
+    parser.add_argument(
+        "-b", "--bind", default="0.0.0.0", help="The address to listen on"
+    )
+    parser.add_argument(
+        "-p", "--port", default=1502, type=int, help="The TCP port to listen on"
+    )
+    parser.add_argument(
+        "-l", "--logger", required=True, help="The IP address of the logger"
+    )
+    parser.add_argument(
+        "-s",
+        "--serial",
+        required=True,
+        type=int,
+        help="The serial number of the logger",
+    )
+    args = parser.parse_args()
+
+    asyncio.run(run_proxy(args.bind, args.port, args.logger, args.serial))
+
+
+if __name__ == "__main__":
+    main()