prevent duplicate connections

game-server/src/main/kotlin/work/fking/pangya/game/GameServer.kt

@@ -51,7 +51,7 @@ class GameServer(
 
  fun registerPlayer(
  channel: Channel,
- sessionInfo: SessionClient.SessionInfo,
+ sessionInfo: SessionClient.HandoverInfo,
  playerWallet: PlayerWallet,
  characterRoster: CharacterRoster,
  caddieRoster: CaddieRoster,
@@ -86,6 +86,7 @@ class GameServer(
  player.currentRoom?.removePlayer(player)
  player.currentChannel?.removePlayer(player)
  players.remove(player)
+ sessionClient.unregisterSession(player)
  LOGGER.info("{} disconnected", player.nickname)
  }
 

game-server/src/main/kotlin/work/fking/pangya/game/SessionClient.kt

@@ -4,23 +4,28 @@ import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
 import com.fasterxml.jackson.module.kotlin.readValue
 import io.lettuce.core.RedisClient
 import io.lettuce.core.api.sync.RedisCommands
+import work.fking.pangya.game.player.Player
 
 class SessionClient(
- private val redisCommands: RedisCommands<String, String>
+ private val redis: RedisCommands<String, String>
 ) {
  constructor(redisClient: RedisClient) : this(redisClient.connect().sync())
 
  private val objectMapper = jacksonObjectMapper()
 
- fun loadSession(sessionKey: String): SessionInfo? {
- val json = redisCommands[sessionKey] ?: return null
- return objectMapper.readValue<SessionInfo>(json)
+ fun unregisterSession(player: Player) {
+ redis.del("session-${player.username}")
+ }
+
+ fun loadHandoverInfo(loginKey: String): HandoverInfo? {
+ val json = redis[loginKey] ?: return null
+ return objectMapper.readValue<HandoverInfo>(json)
  }
 
  @JvmRecord
- data class SessionInfo(
+ data class HandoverInfo(
  val targetServerId: Int,
- val sessionKey: String,
+ val loginKey: String,
  val uid: Int,
  val username: String,
  val nickname: String,

game-server/src/main/kotlin/work/fking/pangya/game/net/HandoverHandler.kt

@@ -38,7 +38,7 @@ class HandoverHandler(
  buffer.readIntLE()
  val sessionKey = buffer.readPString()
  LOGGER.info("Successful handover username={}, uid={}, clientVersion={}, loginKey={}, sessionKey={}", username, uid, clientVersion, loginKey, sessionKey)
- gameServer.runTask(HandoverTask(gameServer, ctx.channel(), cryptKey, sessionKey))
+ gameServer.runTask(HandoverTask(gameServer, ctx.channel(), cryptKey, loginKey))
  }
 
  override fun exceptionCaught(ctx: ChannelHandlerContext, cause: Throwable) {

game-server/src/main/kotlin/work/fking/pangya/game/task/HandoverTask.kt

@@ -27,19 +27,19 @@ class HandoverTask(
  private val gameServer: GameServer,
  private val channel: Channel,
  private val cryptKey: Int,
- private val sessionKey: String
+ private val loginKey: String
 ) : Runnable {
 
  override fun run() {
- val sessionInfo: SessionClient.SessionInfo? = try {
- gameServer.sessionClient.loadSession(sessionKey)
+ val sessionInfo: SessionClient.HandoverInfo? = try {
+ gameServer.sessionClient.loadHandoverInfo(loginKey)
  } catch (e: Exception) {
- LOGGER.warn("Handover error sessionKey={}, message={}", sessionKey, e.message)
+ LOGGER.warn("Handover error loginKey={}, message={}", loginKey, e.message)
  channel.writeAndFlush(HandoverReplies.error(HandoverResult.CANNOT_CONNECT_LOGIN_SERVER))
  return
  }
  if (sessionInfo == null) {
- LOGGER.warn("Handover failed, unknown sessionKey={}", sessionKey)
+ LOGGER.warn("Handover failed, unknown loginKey={}", loginKey)
  channel.writeAndFlush(HandoverReplies.error(HandoverResult.CANNOT_CONNECT_LOGIN_SERVER))
  return
  }

login-server/src/main/kotlin/work/fking/pangya/login/Bootstrap.kt

@@ -12,8 +12,7 @@ import work.fking.pangya.discovery.DiscoveryClient
 import work.fking.pangya.discovery.HeartbeatPublisher
 import work.fking.pangya.discovery.ServerType.LOGIN
 import work.fking.pangya.login.auth.DatabaseAuthenticator
-import work.fking.pangya.login.auth.NOOP_AUTHENTICATOR
-import work.fking.pangya.login.auth.SessionClient
+import work.fking.pangya.login.session.SessionClient
 import work.fking.pangya.login.persistence.AccountRepository
 import java.nio.file.Files
 import java.nio.file.Path

login-server/src/main/kotlin/work/fking/pangya/login/LoginServer.kt

@@ -7,11 +7,12 @@ import org.slf4j.LoggerFactory
 import work.fking.pangya.discovery.DiscoveryClient
 import work.fking.pangya.discovery.ServerType
 import work.fking.pangya.login.auth.Authenticator
-import work.fking.pangya.login.auth.SessionClient
 import work.fking.pangya.login.auth.UserInfo
+import work.fking.pangya.login.net.LoginState.HANDED_OVER
 import work.fking.pangya.login.net.pipe.ServerChannelInitializer
 import work.fking.pangya.login.packet.outbound.LoginReplies
 import work.fking.pangya.login.packet.outbound.ServerListReplies
+import work.fking.pangya.login.session.SessionClient
 import work.fking.pangya.networking.selectBestEventLoopAvailable
 import work.fking.pangya.networking.selectBestServerChannelAvailable
 import java.net.InetAddress
@@ -56,7 +57,11 @@ class LoginServer(
 
  private fun onPlayerDisconnect(player: Player) {
  LOGGER.info("{} disconnected", player.username)
- sessionClient.unregisterSession(player)
+
+ if (player.state != HANDED_OVER) {
+ sessionClient.unregisterSession(player)
+ }
+ sessionClient.expireHandoverInfo(player)
  }
 
  fun start() {

login-server/src/main/kotlin/work/fking/pangya/login/net/LoginState.kt

@@ -24,7 +24,12 @@ enum class LoginState {
  /**
  * Player is fully authenticated, has a valid nickname and has a base character.
  */
- LOGGED_IN;
+ LOGGED_IN,
+
+ /**
+ * Player has been handed over to a game server.
+ */
+ HANDED_OVER;
 
  fun validTransition(to: LoginState): Boolean {
  return when (this) {
@@ -33,7 +38,8 @@ enum class LoginState {
  SELECTING_NICKNAME -> to == SELECTED_NICKNAME
  SELECTED_NICKNAME -> to == LOGGED_IN || to == SELECTING_CHARACTER
  SELECTING_CHARACTER -> to == SELECTING_NICKNAME || to == LOGGED_IN
- LOGGED_IN -> false
+ LOGGED_IN -> to == HANDED_OVER
+ HANDED_OVER -> false
  }
  }
 }

login-server/src/main/kotlin/work/fking/pangya/login/net/pipe/LoginHandler.kt

@@ -9,6 +9,7 @@ import io.netty.handler.timeout.ReadTimeoutException
 import org.slf4j.LoggerFactory
 import work.fking.pangya.login.LoginServer
 import work.fking.pangya.login.packet.outbound.LoginReplies
+import work.fking.pangya.login.packet.outbound.LoginReplies.Error.INCORRECT_USERNAME_PASSWORD
 import work.fking.pangya.login.task.LoginTask
 import work.fking.pangya.networking.crypt.PangCrypt
 import work.fking.pangya.networking.crypt.PangCrypt.PangCryptException
@@ -54,7 +55,7 @@ class LoginHandler(
  val loginKey = buffer.readPString()
 
  LOGGER.debug("Rejecting reconnect for username={} uid={} loginKey={}", username, playerUid, loginKey)
- ctx.writeAndFlush(LoginReplies.error(LoginReplies.Error.INCORRECT_USERNAME_PASSWORD))
+ ctx.writeAndFlush(LoginReplies.error(INCORRECT_USERNAME_PASSWORD))
  }
 
  override fun exceptionCaught(ctx: ChannelHandlerContext, cause: Throwable) {

login-server/src/main/kotlin/work/fking/pangya/login/packet/outbound/LoginReplies.kt

@@ -46,6 +46,7 @@ object LoginReplies {
  }
  }
 
+ // TODO: We're probably doing something wrong here because it doesn't match any of the documented stuff
  fun error(error: Error, message: String = ""): OutboundPacket {
  return OutboundPacket { buffer: ByteBuf ->
  buffer.writeShortLE(RESULT_PACKET_ID)
@@ -86,7 +87,6 @@ object LoginReplies {
  INCORRECT_SSN(0xC),
  INCORRECT_USERNAME(0xD),
  WHITELISTED_USERS_ONLY(0xE),
- SERVER_MAINTENANCE(0xF),
- GEO_BLOCKED(0x10)
+ SERVER_MAINTENANCE(0xF)
  }
 }

login-server/src/main/kotlin/work/fking/pangya/login/session/HandoverInfo.kt

@@ -0,0 +1,11 @@
+package work.fking.pangya.login.session
+
+data class HandoverInfo(
+ val targetServerId: Int,
+ val loginKey: String,
+ val uid: Int,
+ val username: String,
+ val nickname: String,
+ val characterIffId: Int?,
+ val characterHairColor: Int?
+)

login-server/src/main/kotlin/work/fking/pangya/login/auth/SessionClient.kt → login-server/src/main/kotlin/work/fking/pangya/login/session/SessionClient.kt

@@ -1,46 +1,48 @@
-package work.fking.pangya.login.auth
+package work.fking.pangya.login.session
 
 import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
 import io.lettuce.core.RedisClient
 import io.lettuce.core.api.sync.RedisCommands
 import work.fking.pangya.login.Player
 
 class SessionClient(
- private val redisCommands: RedisCommands<String, String>
+ private val redis: RedisCommands<String, String>
 ) {
  private val objectMapper = jacksonObjectMapper()
 
  constructor(redisClient: RedisClient) : this(redisClient.connect().sync())
 
- fun registerSession(player: Player, serverId: Int) {
+ fun sessionKeyForUsername(username: String): String? {
+ return redis["session-$username"]
+ }
+
+ fun registerSession(player: Player) {
+ redis["session-${player.username}"] = player.sessionKey
+ }
+
+ fun unregisterSession(player: Player) {
+ redis.del("session-${player.username}")
+ }
+
+ fun registerHandoverInfo(player: Player, serverId: Int) {
  val nickname = player.nickname
  requireNotNull(nickname) { "Cannot register session for ${player.username} because it doesn't have a nickname set" }
 
- val userInfo = SessionInfo(
+ val userInfo = HandoverInfo(
  targetServerId = serverId,
- sessionKey = player.sessionKey,
+ loginKey = player.loginKey,
  uid = player.uid,
  username = player.username,
  nickname = nickname,
  characterIffId = player.pickedCharacterIffId,
  characterHairColor = player.pickedCharacterHairColor
  )
- redisCommands[player.sessionKey] = objectMapper.writeValueAsString(userInfo)
+ redis[player.loginKey] = objectMapper.writeValueAsString(userInfo)
  }
 
- fun unregisterSession(player: Player) {
+ fun expireHandoverInfo(player: Player) {
  // This is called once the player disconnects from the login server, then,
  // the game server has around 10 seconds to retrieve the session before it expires
- redisCommands.expire(player.sessionKey, 10)
+ redis.expire(player.loginKey, 10)
  }
-
- private data class SessionInfo(
- val targetServerId: Int,
- val sessionKey: String,
- val uid: Int,
- val username: String,
- val nickname: String,
- val characterIffId: Int?,
- val characterHairColor: Int?
- )
 }

login-server/src/main/kotlin/work/fking/pangya/login/session/SessionInfo.kt

@@ -0,0 +1,8 @@
+package work.fking.pangya.login.session
+
+import java.time.ZonedDateTime
+
+data class SessionInfo(
+ val key: String,
+ val createdAt: ZonedDateTime = ZonedDateTime.now()
+)

login-server/src/main/kotlin/work/fking/pangya/login/task/HandoverTask.kt

@@ -3,6 +3,7 @@ package work.fking.pangya.login.task
 import org.slf4j.LoggerFactory
 import work.fking.pangya.login.LoginServer
 import work.fking.pangya.login.Player
+import work.fking.pangya.login.net.LoginState
 import work.fking.pangya.login.packet.outbound.LoginReplies
 
 private val LOGGER = LoggerFactory.getLogger(HandoverTask::class.java)
@@ -15,7 +16,8 @@ class HandoverTask(
 
  override fun run() {
  LOGGER.info("Player {} is being handed over to serverId={} with loginKey={} and sessionKey={}", player.uid, serverId, player.loginKey, player.sessionKey)
- runCatching { server.sessionClient.registerSession(player, serverId) }.onFailure { throw RuntimeException("Failed to register player session") }
+ runCatching { server.sessionClient.registerHandoverInfo(player, serverId) }.onFailure { throw RuntimeException("Failed to register player session") }
  player.writeAndFlush(LoginReplies.sessionKey(player.sessionKey))
+ player.state = LoginState.HANDED_OVER
  }
 }

login-server/src/main/kotlin/work/fking/pangya/login/task/LoginTask.kt

@@ -15,8 +15,10 @@ import work.fking.pangya.login.net.LoginState.SELECTING_CHARACTER
 import work.fking.pangya.login.net.LoginState.SELECTING_NICKNAME
 import work.fking.pangya.login.net.pipe.ProtocolDecoder
 import work.fking.pangya.login.packet.outbound.LoginReplies
+import work.fking.pangya.login.packet.outbound.LoginReplies.Error.INCORRECT_USERNAME_PASSWORD
+import work.fking.pangya.login.packet.outbound.LoginReplies.Error.INVALID_ID
 
-private val PROTOCOL: ClientProtocol = ClientProtocol(ClientPacketType.values())
+private val PROTOCOL: ClientProtocol = ClientProtocol(ClientPacketType.entries.toTypedArray())
 private val LOGGER = LoggerFactory.getLogger(LoginTask::class.java)
 
 class LoginTask(
@@ -38,7 +40,15 @@ class LoginTask(
  }
 
  private fun onSuccessAuth(userInfo: UserInfo) {
+ val sessionClient = loginServer.sessionClient
+ val userSession = sessionClient.sessionKeyForUsername(username)
+
+ if (userSession == null) {
+ duplicateConnection()
+ return
+ }
  val player = loginServer.registerPlayer(channel, userInfo)
+ sessionClient.registerSession(player)
 
  val pipeline = channel.pipeline()
  pipeline.remove("loginHandler")
@@ -61,6 +71,10 @@ class LoginTask(
  }
 
  private fun onInvalidCredentials() {
- channel.writeAndFlush(LoginReplies.error(LoginReplies.Error.INCORRECT_USERNAME_PASSWORD))
+ channel.writeAndFlush(LoginReplies.error(INCORRECT_USERNAME_PASSWORD))
+ }
+
+ private fun duplicateConnection() {
+ channel.writeAndFlush(LoginReplies.error(INVALID_ID, "Account is already logged in."))
  }
 }