Table of Contents

Network System

This page describes the current network stack used by Moongate v2.

Core Components

  • MoongateTCPServer (Moongate.Network)
    • Listens on endpoints and raises connect/disconnect/data events.
  • MoongateTCPClient (Moongate.Network)
    • Per-connection transport abstraction with send/receive and middleware support.
  • NetworkService (Moongate.Server.Services.Network)
    • Owns protocol framing/parsing and session lifecycle.
  • GameNetworkSessionService
    • Stores active GameSession instances keyed by session id.
  • PacketRegistry / PacketTable
    • Resolve opcode metadata and packet factories.

Inbound Flow

  1. OnDataReceived receives bytes from MoongateTCPClient.
  2. Bytes are appended to per-session pending buffer (GameNetworkSession.WithPendingBytesLock(...)).
  3. NetworkService resolves packet length:
    • fixed length from PacketDescriptor.Length
    • variable length from bytes [1..2] (big-endian, includes header)
  4. Raw packet bytes are parsed with packet.TryParse(rawPacket).
  5. Parsed packet is published to IMessageBusService.

Protection currently implemented:

  • max pending buffer size
  • max declared packet length
  • unknown opcode handling with protocol-violation counter
  • disconnect after repeated violations

Outbound Flow

  1. Handlers/listeners enqueue packets into IOutgoingPacketQueue.
  2. GameLoopService drains queue each loop iteration.
  3. IOutboundPacketSender serializes packet with SpanWriter and sends through MoongateTCPClient.SendAsync(...).
  4. If packet logging is enabled, hex dump is written with PacketData context.

Current gameplay-facing outbound examples:

  • PlayerStatusHandler emits PlayerStatusPacket (0x11) for basic status requests
  • PlayerStatusHandler emits SkillListPacket (0x3A) for skill window requests
  • ChatSystemService emits ChatCommandPacket (0xB2) for classic conference chat UI, channel membership, PMs, moderator/voice changes, and system responses
  • ItemHandler responds to classic book traffic:
    • 0xD4 saves writable title / author
    • 0x66 serves page requests and writable page saves

Compression and Middleware

GameNetworkSession can toggle transport middleware:

  • EnableCompression() / DisableCompression()
  • EnableEncryption() / DisableEncryption()

Compression middleware is attached/removed on MoongateTCPClient pipeline.

Session Lifecycle

  • connect: create or refresh GameSession + GameNetworkSession
  • disconnect: remove session from GameNetworkSessionService
  • protocol states: AwaitingSeed, Authenticated, InGame, etc.

Current Request Flows

Important current request/response pairs:

  • 0x34 Get Player Status
    • BasicStatus -> 0x11 Player Status
    • RequestSkills -> 0x3A Skill List
  • 0xB5 Open Chat Window
    • client open request -> server creates/refreshes runtime chat user and returns 0xB2 chat-window command
  • 0xB3 Chat Text
    • action dispatch in IChatSystemService
    • supports conference message/join/create/rename/password, PM, ignore, ops/voice, whois, kick, emote
  • 0x66 Book Pages
    • page request -> server book page response
    • writable page save -> server persists updated page content
  • 0xD4 Book Header New
    • writable header save -> server persists title / author

Useful Runtime Diagnostics

  • Registered packets are logged at startup (NetworkService.ShowRegisteredPackets()).
  • Unknown opcode warnings include descriptor description when available.
  • Metrics exposed via INetworkMetricsSource.

Previous: Architecture Overview | Next: Game Loop

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