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Direct-Connect Server Join Flow

Direct-Connect UI Layer

Class: ServerListManager (line 46830) File: Assembly-CSharp.decompiled.cs

The UI component owns the direct-connect input field and button. Key methods:

  • OnDirectConnect() (line 47137): Button callback. Trims _addressInputField.text and passes to NetworkClient.JoinClientFromMenu().
  • OnInputValueChanged() (line 46913): Called on every keystroke via _addressInputField.onValueChanged listener. Enables/disables the "Connect" button based on IsValidIpAddressAndPort().
  • IsValidIpAddressAndPort() (line 46918): Returns ValidIpPattern.Match(address).Success.

Field: _addressInputField is a TMP_InputField (line 46836).

IP Address Validation (Hostname Blocker)

Static Regex: ValidIpPattern (line 46878)

private static readonly Regex ValidIpPattern = new Regex("^(?:[0-9]{1,3}\.){3}[0-9]{1,3}:[0-9]{1,5}\s*$");

Pattern matches only IPv4 dotted-quad format with colon-delimited port: ###.###.###.###:port. No hostname support. This regex blocks any domain name input—the button remains grayed out until the user types an IP.

This is the choke point for the hostname problem. Any Harmony patch enabling hostnames must either: 1. Patch IsValidIpAddressAndPort() to accept hostnames, or 2. Replace ValidIpPattern with a less restrictive regex, or 3. Patch the button-enabling logic upstream in OnInputValueChanged().

Connection Initiation

Method: NetworkClient.JoinClientFromMenu() (line 198051)

Flow: 1. Splits input on ':' to extract address and port. 2. Special case: if length == 1 and the string is 17 chars, treats it as a SteamId and calls JoinWithSteamP2P(). 3. If length != 2, shows error dialog. 4. Parses port as ushort (line 198071). 5. Calls Assets.Scripts.Networking.NetworkManager.StartClient(address, port, localPort) (line 198073).

Method: NetworkManager.StartClient(string address, ushort port, ushort localPort) (line 255869)

  • Uses RakNet directly: calls Instance.rakNet.Connect(array, port, ReadOnlySpan<byte>.Empty, null) (line 255889).
  • Converts the address string to a null-terminated UTF-8 byte array (lines 255885–255888) and passes it to RakNet.
  • On success, stores address and port in NetworkClient.Address and NetworkClient.Port static fields (lines 255898–255899) and logs "Connected to {address} on port {port}".

Whether RakNet performs DNS resolution on a hostname-shaped byte array is not visible in the C# decompile — RakPeerInterface.Connect is a managed wrapper over native RakNet code. The C# layer does not pre-resolve. See "Open questions" below.

DNS helper already in the game

Method: NetworkManager.ResolveIpAddress(string address) (line 255859, immediately above StartClient)

public static string ResolveIpAddress(string address)
{
    IPAddress[] hostAddresses = Dns.GetHostAddresses(address);
    if (hostAddresses.Length == 0)
    {
        return string.Empty;
    }
    return hostAddresses[0].ToString();
}

This static helper resolves a hostname to a dotted-quad string (or "" on failure). It is defined but not called from StartClient. A Harmony patch that needs to feed an IP to the game can call this helper directly instead of bundling its own System.Net.Dns invocation.

Harmony patch site #1: NetworkManager.StartClient() (prefix) — call ResolveIpAddress(address) when address is not dotted-quad, substitute the result. Defensive against unknown RakNet DNS behavior. Harmony patch site #2: NetworkClient.JoinClientFromMenu() (prefix) — alternative interception site; can preprocess the input string before the colon split / port parse.

Server Persistence (Last Server Forgotten)

Finding: No PlayerPrefs entry for the last direct-connect address exists in ServerListManager or NetworkClient.

PlayerPrefs used in ServerListManager (line 46899–46901, 46927–46935, 46942–46962): - FILTER_VERSION, FILTER_PASSWORD, FILTER_EMPTY (filter toggles) - JoinSortBy (sort preference)

None of these store the address field. The _addressInputField text is not persisted anywhere. On app quit, it is lost.

Harmony patch site #3: ServerListManager.OnDisable() or application quit hook to save _addressInputField.text to PlayerPrefs (e.g., key LAST_DIRECT_CONNECT_ADDRESS).

Harmony patch site #4: ServerListManager.Awake() or Start() to restore the saved address and repopulate _addressInputField.text.

Port Handling

Port is extracted from the input string during parsing in JoinClientFromMenu() (line 198071): 

ushort num = ushort.Parse(array[1]);
ushort localPort = (ushort)(num + 1);

The local port is automatically set to one higher than the server port. Both are passed to StartClient(). No separate port input field exists in the UI; port is baked into the "address:port" string format required by the regex.

Verification history

  • 2026-05-14: Initial findings. Decompiled v0.2.6228.27061. Located ServerListManager, ValidIpPattern regex (IPv4-only), JoinClientFromMenu parsing, RakNet integration point, no persistence on address field.
  • 2026-05-14: Added NetworkManager.ResolveIpAddress (line 255859) as a ready-made DNS helper the game already ships. Walked back the unverified claim that RakPeerInterface.Connect resolves hostnames internally; the C# decompile does not reveal native RakNet behavior, so a patch should not assume it.

Open questions

  • Does the native RakPeerInterface.Connect resolve hostnames internally, or does it require a numeric IP in the UTF-8 byte array? Not visible in the C# decompile. Resolved cheaply at implementation time by either (a) pre-resolving with NetworkManager.ResolveIpAddress defensively or (b) testing with a hostname and inspecting RakNet's failure mode.
  • What does RakNet do if a hostname fails to resolve? Likely returns ConnectionAttemptResult != ConnectionAttemptStarted, which StartClient already surfaces via ConsoleWindow.PrintAction(...) (line 255892) and NetworkClient.OnJoinFailed(). Verify when implementing.