Fix 0.6.5 connless header

tests/packets6/conless_info6_test.py

@@ -0,0 +1,49 @@
+from twnet_parser.packet import parse6, TwPacket, PacketHeader6
+from twnet_parser.messages6.connless.info import MsgInfo
+
+def test_unpack_info():
+    """
+    Sent by a vanilla 0.6.5 server
+    copied from a real traffic capture
+    """
+    data = \
+        b'\xff\xff' \
+        b'\xff\xff\xff\xff\xff\xff\xff\xff\x69\x6e\x66\x33\x32\x00\x30\x2e' \
+        b'\x36\x2e\x35\x00\x75\x6e\x6e\x61\x6d\x65\x64\x20\x73\x65\x72\x76' \
+        b'\x65\x72\x00\x42\x6c\x6d\x61\x70\x43\x68\x69\x6c\x6c\x00\x44\x4d' \
+        b'\x00\x30\x00\x31\x00\x38\x00\x31\x00\x38\x00\x6e\x61\x6d\x65\x6c' \
+        b'\x65\x73\x73\x20\x74\x65\x65\x00\x00\x2d\x31\x00\x30\x00\x31\x00'
+
+    packet = parse6(data)
+
+    assert packet.version == '0.6'
+    assert packet.header.ack == 0
+    assert packet.header.num_chunks == None
+    assert packet.header.token == b'\xff\xff\xff\xff'
+    assert packet.header.flags.token is False
+    assert packet.header.flags.control is False
+    assert packet.header.flags.connless is True
+    assert packet.header.flags.resend is False
+    assert packet.header.flags.compression is False
+
+    assert len(packet.messages) == 1
+
+    msg: MsgInfo = packet.messages[0]
+
+    assert msg.message_name == 'connless.info'
+    assert msg.token == 2
+    assert msg.version == '0.6.5'
+    assert msg.name == "unnamed server"
+    assert msg.map == "BlmapChill"
+    assert msg.game_type == "DM"
+    assert msg.flags == 0
+    assert msg.num_players == 1
+    assert msg.max_players == 8
+    assert msg.num_clients == 1
+    assert msg.max_clients == 8
+
+    repack = packet.pack()
+    assert repack == data
+
+
+

twnet_parser/packet.py

@@ -36,6 +36,7 @@ CHUNKFLAG7_RESEND = 2
 
 PACKET_HEADER7_SIZE = 7
 CONNLESS_PACKET_HEADER7_SIZE = 9
+CONNLESS_PACKET_HEADER6_SIZE = 6
 
 class PacketFlags7(PrettyPrint):
     def __init__(self) -> None:
@@ -115,9 +116,7 @@ class PacketHeader6(PrettyPrint):
         if self.num_chunks is None:
             self.num_chunks = 0
         if self.flags.connless:
-            return bytes([ \
-                ((PACKETFLAG6_CONNLESS<<2)&0xfc) | (self.connless_version&0x03)
-            ]) + self.token + self.response_token
+            return b'\xff\xff\xff\xff\xff\xff'
         packed = bytes([ \
             ((flags << 2)&0xfc) | ((self.ack>>8)&0x03), \
             self.ack&0xff, \
@@ -250,6 +249,15 @@ class PacketHeaderParser6():
         flags.connless = (flag_bits & PACKETFLAG6_CONNLESS) != 0
         flags.resend = (flag_bits & PACKETFLAG6_RESEND) != 0
         flags.compression = (flag_bits & PACKETFLAG6_COMPRESSION) != 0
+        if flags.connless:
+            # conless packets send FF
+            # as the flag byte
+            # but setting the connless bit basically means
+            # all other flags are false implicitly
+            flags.token = False
+            flags.control = False
+            flags.resend = False
+            flags.compression = False
         return flags
 
     def parse_ack(self, header_bytes: bytes) -> int:
@@ -396,7 +404,7 @@ class PacketParser():
         pck.header = PacketHeaderParser6().parse_header(data)
         header_size = PACKET_HEADER7_SIZE
         if pck.header.flags.connless:
-            header_size = CONNLESS_PACKET_HEADER7_SIZE
+            header_size = CONNLESS_PACKET_HEADER6_SIZE
         elif not pck.header.flags.token:
             header_size = 3
         pck.payload_raw = data[header_size:]
@@ -406,7 +414,7 @@ class PacketParser():
             pck.messages.append(ctrl_msg)
             return pck
         if pck.header.flags.connless:
-            connless_msg: ConnlessMessage = match_connless6(data[header_size:17], data[17:])
+            connless_msg: ConnlessMessage = match_connless6(data[header_size:14], data[14:])
             pck.messages.append(connless_msg)
             return pck
         if pck.header.flags.compression: