[1.1.39] IPv6 connection error on headless

[oof2win2]

Hi. I have multiple servers and yesterday 4 of them crashed due to an IPv6 connection being attempted. I believe that it is odd, since the servers are set up to not accept IPv6 connections (or the IPv6 socket at least fails to initiate)

Here is a forum thread that has been moved to techincal help earlier this year: viewtopic.php?f=49&t=98636

Here is the relevant part of the log:

Code: Select all

   0.000 2021-09-19 17:48:21; Factorio 1.1.39 (build 58937, linux64, headless)
   0.034 Operating system: Linux (Ubuntu 20.04)
   0.034 Program arguments: "/opt/factorio/servers/awf-irregular/bin/x64/factorio" "--config" "/opt/factorio/servers/awf-irregular/config/config.ini" "--port" "39006" "--start-server-load-latest" "--server-settings" "/opt/factorio/servers/awf-irregular/server-settings.json" "--server-adminlist" "/opt/factorio/servers/server-adminlist.json" "--server-banlist" "/opt/factorio/banlist.json" "--rcon-port" "39006" "--rcon-password" <private> 
   0.034 Read data path: /opt/factorio/servers/awf-irregular/data
   0.034 Write data path: /opt/factorio/servers/awf-irregular [108473/223812MB]
   0.034 Binaries path: /opt/factorio/servers/awf-irregular/bin
   0.041 System info: [CPU: Intel(R) Core(TM) i7-6800K CPU @ 3.40GHz, 12 cores, RAM: 32017 MB]
   0.041 Environment: DISPLAY=<unset> WAYLAND_DISPLAY=<unset> DESKTOP_SESSION=<unset> XDG_SESSION_DESKTOP=<unset> XDG_CURRENT_DESKTOP=<unset> __GL_FSAA_MODE=<unset> __GL_LOG_MAX_ANISO=<unset> __GL_SYNC_TO_VBLANK=<unset> __GL_SORT_FBCONFIGS=<unset> __GL_YIELD=<unset>
   0.041 Running in headless mode
   0.082 Loading mod core 0.0.0 (data.lua)
   0.137 Loading mod base 1.1.39 (data.lua)
   0.427 Loading mod base 1.1.39 (data-updates.lua)
   0.529 Checksum for core: 2513062293
   0.529 Checksum of base: 1955203571
   0.722 Prototype list checksum: 3034860339
   0.766 Info PlayerData.cpp:71: Local player-data.json available, timestamp 1632073701
   0.766 Info PlayerData.cpp:78: Cloud player-data.json unavailable
   0.769 Factorio initialised
   0.771 Info ServerSynchronizer.cpp:29: nextHeartbeatSequenceNumber(0) initialized Synchronizer nextTickClosureTick(0).
   0.771 Info ServerMultiplayerManager.cpp:780: updateTick(4294967295) changing state from(Ready) to(PreparedToHostGame)
   0.771 Info ServerMultiplayerManager.cpp:780: updateTick(4294967295) changing state from(PreparedToHostGame) to(CreatingGame)
   0.771 Loading map /opt/factorio/servers/awf-irregular/saves/_autosave1.zip: 15229068 bytes.
   0.822 Loading level.dat: 51432683 bytes.
   0.836 Info Scenario.cpp:197: Map version 1.1.39-0
   1.954 Loading script.dat: 560507 bytes.
...
   2.026 Info UDPSocket.cpp:27: Opening socket at (IP ADDR:({X.X.X.X:39006}))
   2.028 Warning UDPSocket.cpp:156: Failed to open IPv6 socket (Address family not supported by protocol), continuing with IPv4 only
   2.028 Hosting game at IP ADDR:({X.X.X.X:39006})
   2.029 Info HttpSharedState.cpp:54: Downloading https://auth.factorio.com/generate-server-padlock-2?api_version=4
   2.410 Info AuthServerConnector.cpp:68: Obtained serverPadlock for serverHash (TUfPhTG8ssE3Pqj0iEInTAmMccQY8b6l) from the auth server.
   2.410 Info ServerMultiplayerManager.cpp:780: updateTick(10854001) changing state from(CreatingGame) to(InGame)
   2.548 Info ServerRouter.cpp:642: Asking pingpong servers (pingpong1.factorio.com:34197, pingpong2.factorio.com:34197, pingpong3.factorio.com:34197, pingpong4.factorio.com:34197) for own address
   2.549 Info RemoteCommandProcessor.cpp:130: Starting RCON interface at IP ADDR:({X.X.X.X:39006})
   2.549 Info CommandLineMultiplayer.cpp:278: Maximum segment size = 100; minimum segment size = 25; maximum-segment-size peer count = 10; minimum-segment-size peer count = 20
   2.667 Info ServerRouter.cpp:525: Own address is IP ADDR:({X.X.X.X:39006}) (confirmed by pingpong1)
   2.668 Info ServerRouter.cpp:525: Own address is IP ADDR:({X.X.X.X:39006}) (confirmed by pingpong3)
   2.836 Info ServerRouter.cpp:525: Own address is IP ADDR:({X.X.X.X:39006}) (confirmed by pingpong4)
   3.023 Info MatchingServer.cpp:114: Matching server game `10703133` has been created.
   3.038 Info ServerMultiplayerManager.cpp:712: Matching server connection resumed
...
266279.748 Error Util.cpp:83: Cannot send to IPv6 addresses when IPv6 socket is closed
266280.372 Info ServerMultiplayerManager.cpp:113: Disconnecting multiplayer connection.
266280.372 Info ServerMultiplayerManager.cpp:780: updateTick(4294967295) changing state from(InGame) to(DisconnectingScheduled)
266280.455 Info ServerMultiplayerManager.cpp:140: Quitting multiplayer connection.
266280.455 Info ServerMultiplayerManager.cpp:780: updateTick(4294967295) changing state from(DisconnectingScheduled) to(Closed)
266280.456 Info HttpSharedState.cpp:54: Downloading https://multiplayer.factorio.com/remove-game/10703133
266280.942 Info UDPSocket.cpp:218: Closing socket
266280.942 Info UDPSocket.cpp:248: Socket closed
266280.944 Goodbye

This bug can obviously be resolved by blocking IPv6 connections network-wide, however I believe that it is a bug, since the server logged that the IPv6 connection was not initated in the first place.

[Rseding91]

Did anything more ever happen with this? We haven't changed the networking code in a long time and what I said on the other topic still applies.

As far as I know (somebody correct me of I'm wrong): in order for the game to get an IPv6 packet it needs to have the socket on the operating system side accept the IPv6 packet and forward it to the game.