Add V1 protocol discovery and upgrade support

scripts/v1_discover.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+"""搜索 V1 工厂协议设备（UDP 4942）。"""
+
+from __future__ import annotations
+
+import argparse
+import ipaddress
+import json
+import secrets
+import socket
+import struct
+import time
+from typing import Any
+
+PORT = 4942
+REQUEST = 0x5A0EFF00
+RESPONSE = 0x5A0EFF01
+MAX_DATA = 1024 * 1024
+
+
+def frame(command: int, payload: bytes) -> bytes:
+    return struct.pack("!II", command, len(payload)) + payload
+
+
+def parse_frame(packet: bytes) -> tuple[int, bytes]:
+    if len(packet) < 8:
+        raise ValueError("packet shorter than V1 header")
+    command, length = struct.unpack("!II", packet[:8])
+    if length > MAX_DATA or len(packet) != 8 + length:
+        raise ValueError("invalid V1 payload length")
+    return command, packet[8:]
+
+
+def discover(timeout: float, interface: str | None) -> int:
+    session = secrets.randbelow(0x7FFFFFFF) + 1
+    request = frame(REQUEST, json.dumps({"session": session}).encode("utf-8"))
+    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+    sock.settimeout(min(0.5, timeout))
+    try:
+        # Bind the documented client port. If another discovery utility owns
+        # it, stop and report the conflict instead of silently using another port.
+        sock.bind((interface or "0.0.0.0", PORT))
+        sock.sendto(request, ("255.255.255.255", PORT))
+        deadline = time.monotonic() + timeout
+        seen: set[tuple[str, str]] = set()
+        while time.monotonic() < deadline:
+            try:
+                packet, address = sock.recvfrom(MAX_DATA + 8)
+            except socket.timeout:
+                continue
+            try:
+                command, data = parse_frame(packet)
+                obj: Any = json.loads(data.decode("utf-8"))
+                if command != RESPONSE or not isinstance(obj, dict):
+                    continue
+                if obj.get("session") != session:
+                    continue
+                key = (address[0], str(obj.get("sn", "")))
+                if key in seen:
+                    continue
+                seen.add(key)
+                print(json.dumps({"source_ip": address[0], "response": obj}, ensure_ascii=False))
+            except (ValueError, UnicodeDecodeError, json.JSONDecodeError):
+                continue
+        return 0
+    finally:
+        sock.close()
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--timeout", type=float, default=3.0)
+    parser.add_argument("--interface", help="optional local IPv4 address to bind")
+    args = parser.parse_args()
+    if args.timeout <= 0:
+        parser.error("--timeout must be positive")
+    if args.interface:
+        ipaddress.IPv4Address(args.interface)
+    return discover(args.timeout, args.interface)
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())