the files

2026-10-14 06:59:51 +02:00
parent f6175893fc
commit 2040419525
1855 changed files with 6735668 additions and 0 deletions
@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+"""Decode a hex-dump capture of LiteNetLib 1.x traffic.
+
+Input format: alternating timestamp lines and lowercase hex payload lines
+(one UDP payload per line), which is what the in-game capture produces.
+
+    ./tools/decode_lnl.py traffic.txt
+"""
+import re, sys, struct, collections
+
+PROP = {0:'Unreliable',1:'Channeled',2:'Ack',3:'Ping',4:'Pong',5:'ConnectRequest',
+        6:'ConnectAccept',7:'Disconnect',8:'UnconnectedMessage',9:'MtuCheck',10:'MtuOk',
+        11:'Broadcast',12:'Merged',13:'ShutdownOk',14:'PeerNotFound',15:'InvalidProtocol',
+        16:'NatMessage',17:'Empty'}
+
+BATCH_MAGIC = 0x1160
+
+
+def read_packed_uint(d, p):
+    n = d[p] & 0x07
+    if n == 5:
+        return struct.unpack_from('<I', d, p + 1)[0], p + 5
+    v = int.from_bytes(d[p:p + n], 'little')
+    return v >> 3, p + n
+
+
+def decode_ngo(payload):
+    """Decode an NGO batch riding inside a Channeled/Unreliable LiteNetLib payload."""
+    if len(payload) < 16:
+        return "  (too short for a batch header)"
+    magic, count, size = struct.unpack_from('<HHi', payload, 0)
+    bhash = struct.unpack_from('<Q', payload, 8)[0]
+    if magic != BATCH_MAGIC:
+        return f"  not an NGO batch (magic 0x{magic:04x})"
+    out = [f"  NGO batch: count={count} size={size} len={len(payload)} hash=0x{bhash:016x}"]
+    p = 16
+    for i in range(count):
+        if p >= len(payload):
+            break
+        mtype, p = read_packed_uint(payload, p)
+        msize, p = read_packed_uint(payload, p)
+        out.append(f"    [{mtype}] {msize} bytes: {payload[p:p+min(msize,32)].hex()}")
+        p += msize
+    return "\n".join(out)
+
+
+def main(path):
+    lines = open(path).read().splitlines()
+    events, ts = [], None
+    for l in lines:
+        l = l.strip()
+        if re.match(r'^\d{4}-\d\d-\d\d', l):
+            ts = l
+        elif re.fullmatch(r'[0-9a-f]+', l) and len(l) >= 2:
+            events.append((ts, bytes.fromhex(l)))
+
+    hist = collections.Counter()
+    for ts, b in events:
+        prop = b[0] & 0x1f
+        name = PROP.get(prop, f'?{prop}')
+        hist[name] += 1
+        t = ts.split()[1][:12] if ts else ''
+        detail = ''
+        if name == 'ConnectRequest':
+            pid = struct.unpack_from('<i', b, 1)[0]
+            ct = struct.unpack_from('<q', b, 5)[0]
+            asz = b[17]
+            addr = b[18:18 + asz]
+            port = struct.unpack_from('>H', addr, 2)[0]
+            ip = '.'.join(str(x) for x in addr[4:8])
+            detail = (f"protocolId={pid} ct={ct} target={ip}:{port} "
+                      f"connectData={b[18+asz:].hex()}")
+        elif name == 'ConnectAccept':
+            # [1..8] connectionTime, [9] connectionNumber, [10] isReused, [11..14] peerId
+            detail = (f"ct={struct.unpack_from('<q', b, 1)[0]} "
+                      f"connNum={b[9]} reused={b[10]} "
+                      f"peerId={struct.unpack_from('<i', b, 11)[0]}")
+        elif name in ('Ping', 'Pong'):
+            detail = f"seq={struct.unpack_from('<H', b, 1)[0]}"
+        elif name == 'MtuCheck':
+            detail = f"mtu={struct.unpack_from('<i', b, 1)[0]}"
+        print(f"{t:13} {name:16} {len(b):5}  {detail}")
+        if name in ('Channeled', 'Unreliable'):
+            # Channeled carries a 4-byte LNL header, Unreliable a 1-byte one.
+            print(decode_ngo(b[4:] if name == 'Channeled' else b[1:]))
+
+    print("\nhistogram:")
+    for k, v in hist.most_common():
+        print(f"  {k:16} {v}")
+    if not hist['Channeled'] and not hist['Unreliable']:
+        print("\n  NOTE: no data packets at all - the NGO layer never got a chance to speak.")
+    if hist['Ping'] and not hist['Pong']:
+        print("  NOTE: pings with no pongs. These captures carry no direction or port info, so"
+              "\n        note the pings are most likely the SERVER's: it accepted the connection"
+              "\n        and started pinging, while the client is still in Outgoing state and so"
+              "\n        never pongs. Expect a DisconnectTimeout (~5s) loop on the server.")
+    if hist['ConnectRequest'] > 3 and hist['ConnectAccept']:
+        print("  NOTE: repeated ConnectRequests answered by ConnectAccepts. If the connectionTime"
+              "\n        is identical across them it is ONE attempt being resent - the client is"
+              "\n        not acting on the accept. Capture with tcpdump to see if it arrives.")
+
+
+if __name__ == '__main__':
+    main(sys.argv[1] if len(sys.argv) > 1 else 'traffic.txt')