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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.