NahidaImpact/NahidaImpact.Gameserver/Network/Session/NetSession.cs

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2024-01-04 13:48:39 +00:00
using System.Net;
using NahidaImpact.Common.Security;
using NahidaImpact.Gameserver.Controllers.Dispatching;
using NahidaImpact.Gameserver.Controllers.Result;
using NahidaImpact.Protocol;
using Google.Protobuf;
using Microsoft.Extensions.Logging;
namespace NahidaImpact.Gameserver.Network.Session;
internal abstract class NetSession(ILogger<NetSession> logger, NetSessionManager sessionManager, NetCommandDispatcher commandDispatcher) : IDisposable
{
public IPEndPoint EndPoint => _networkUnit!.RemoteEndPoint;
public long SessionId { get; private set; }
private INetworkUnit? _networkUnit;
private readonly ILogger _logger = logger;
private readonly NetSessionManager _sessionManager = sessionManager;
private readonly NetCommandDispatcher _commandDispatcher = commandDispatcher;
protected byte[] EncryptionKey { get; private set; } = MhySecurity.InitialKey;
public abstract ValueTask RunAsync();
public abstract ValueTask SendAsync(NetPacket packet);
public void Establish(long sessionId, INetworkUnit networkUnit)
{
SessionId = sessionId;
_networkUnit = networkUnit;
_sessionManager.Add(this);
}
public async Task NotifyAsync<TNotify>(CmdType cmdType, TNotify notify) where TNotify : IMessage<TNotify>
{
await SendAsync(new()
{
CmdType = cmdType,
Head = Memory<byte>.Empty,
Body = notify.ToByteArray()
});
}
protected async ValueTask<int> ConsumePacketsAsync(Memory<byte> buffer)
{
if (buffer.Length < 12)
return 0;
int consumed = 0;
do
{
(NetPacket? packet, int bytesConsumed) = NetPacket.DecodeFrom(buffer[consumed..]);
consumed += bytesConsumed;
if (packet == null)
return consumed;
IResult? result = await _commandDispatcher.InvokeHandler(packet);
if (result != null)
{
while (result.NextPacket(out NetPacket? serverPacket))
{
await SendAsync(serverPacket);
if (serverPacket.CmdType == CmdType.GetPlayerTokenRsp)
{
InitializeEncryption(1337); // hardcoded MT seed with patch
}
}
_logger.LogInformation("Successfully handled command of type {cmdType}", packet.CmdType);
}
} while (buffer.Length - consumed >= 12);
return consumed;
}
private void InitializeEncryption(ulong seed)
{
EncryptionKey = MhySecurity.GenerateSecretKey(seed);
}
protected async ValueTask<int> ReadWithTimeoutAsync(Memory<byte> buffer, int timeoutSeconds)
{
using CancellationTokenSource cancellationTokenSource = new(TimeSpan.FromSeconds(timeoutSeconds));
return await _networkUnit!.ReceiveAsync(buffer, cancellationTokenSource.Token);
}
protected async ValueTask WriteWithTimeoutAsync(Memory<byte> buffer, int timeoutSeconds)
{
using CancellationTokenSource cancellationTokenSource = new(TimeSpan.FromSeconds(timeoutSeconds));
await _networkUnit!.SendAsync(buffer, cancellationTokenSource.Token);
}
public virtual void Dispose()
{
_networkUnit?.Dispose();
_ = _sessionManager.TryRemove(this);
}
}