Halo: Combat Evolved

Debugging

To enable debugging of the original NTSC version with xbdm (be sure to use the retail xbdm version 5455 if on a retail box due to low memory constraints) replace the single instance of 6A 00 FF 74 24 08 E8 35 with 33 C0 40 C2 04 00 E8 35 in the default.xbe which will skip a call to XnTerm.

System-Link protocol

The messages are encapsulated in Xbox secured network traffic.

enum GameMode {
  CTF = 0,
  Slayer = 1,
  Oddball = 2,
  King = 3,
  Race = 4
};

Server announce request

This is a broadcast message from UDP Port 5151 to port 5150.

The packet is 16 bytes long.

  b'\x01\x0c\x01\x14\x1f\x00\x01zLa(\xe9\x03\xfc\xf7\x00' # Python string  

Server announce response

This is a broadcast message from UDP Port 5150 to port 5151.

The packet is 280 bytes long.

struct {

  ...

  // assert(udp_payload[43:47] == bytes([0x0C,0x00,0x00,0x50]));

  uint32_t unk47; // +47
  uint32_t unk51; // +51
  uint16_t unk55; // +55
  uint32_t unk57; // +57
  wchar_t server_name[62]; // +61 Only 15 symbols will be displayed
  char map_path[128]; // +123

  ...

  uint16_t game_mode; // +251
  uint16_t unk253; // +253
  uint16_t player_count; // +255
  uint16_t unk257; // +257
  uint16_t game_mode_parameter; // +259

  // 1 = game in progress
  // 2 = accepting players (takes priority over "game in progress")
  // 4 = team game (otherwise: free for all)
  // If neither 1 or 2 is provided, then the game is "(closed)"
  uint16_t flags; // +261

  char weird[16]; // +263 contains ASCII string "$;$Dage in a bot"

  uint8_t unk279; // +279
};