From c51f428c98f12b79074d5170aa11b97d5ba7cef1 Mon Sep 17 00:00:00 2001
From: Danil Kolesnikov <d.kolesnikov@innopolis.university>
Date: Mon, 23 Dec 2024 20:54:09 +0300
Subject: [PATCH] initial commit

---
 udod.py | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 udod.py

diff --git a/udod.py b/udod.py
new file mode 100644
index 0000000..eb70746
--- /dev/null
+++ b/udod.py
@@ -0,0 +1,81 @@
+import asyncio
+import socket
+
+
+def shift_seq(seq, byte_shift):
+    result = bytearray(seq)
+    for i in range(len(seq)):
+        result[i] = (result[i] + byte_shift) & 0xff
+    return result
+
+
+def encrypt(data):
+    return shift_seq(data, 15)
+
+
+def decrypt(data):
+    return shift_seq(data, -15)
+
+
+class Duplex:
+    def __init__(self, s1, s1_remote, s1_transform,
+                 s2, s2_remote, s2_transform,
+                 loop, mtu):
+        self.mtu = mtu
+        self.loop = loop
+
+        # loop.create_task(self.stream(s1,s2, s2_remote, s2_transform))
+        loop.create_task(self.stream(s2, s1, s1_remote, s1_transform))
+
+    async def stream(self, rx, tx, tx_addr, transform):
+        print("Starting stream", rx.getsockname(), '>>',  tx_addr)
+        while True:
+            data = await self.loop.sock_recv(rx, self.mtu)
+            # print(rx.getsockname(),'>>', tx_addr, len(data),
+            # data[:20].hex(), transform(data)[:20].hex())
+            await self.loop.sock_sendto(tx, transform(data), tx_addr)
+
+
+async def main():
+    rx = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    rx.setblocking(False)
+    rx.bind((RX_IP, RX_PORT))
+
+    connections = {}
+
+    print("App started")
+    loop = asyncio.get_running_loop()
+
+    while True:
+        data, addr = await loop.sock_recvfrom(rx, RX_MTU)
+        # print("Received "+str(len(data))+" bytes", addr, data[:20])
+
+        if addr in connections.keys():
+            tx = connections[addr]
+        else:
+            connections[addr] = socket.socket(
+                    socket.AF_INET, socket.SOCK_DGRAM)
+            tx = connections[addr]
+            tx.setblocking(False)
+            tx.bind(tx.getsockname())
+            Duplex(rx, addr, RX_ALGO, connections[addr],
+                   (TX_IP, TX_PORT), TX_ALGO, loop, RX_MTU)
+
+        try:
+            tx.sendto(TX_ALGO(data), (TX_IP, TX_PORT))
+        except Exception:
+            print("reconnect", addr)
+            del connections[addr]
+        # print("Sent", TX_ALGO(data)[:20], "to", (TX_IP, TX_PORT))
+
+if __name__ == '__main__':
+    RX_IP = "127.0.0.1"
+    RX_PORT = 5005
+    RX_MTU = 1500
+    RX_ALGO = encrypt
+
+    TX_IP = "194.135.105.21"
+    TX_PORT = 5005
+    TX_ALGO = decrypt
+
+    asyncio.run(main())