//====== Copyright Valve Corporation, All rights reserved. ==================== // // Networking API similar to Berkeley sockets, but for games. // - connection-oriented API (like TCP, not UDP) // - but unlike TCP, it's message-oriented, not stream-oriented // - mix of reliable and unreliable messages // - fragmentation and reassembly // - Supports connectivity over plain UDPv4 // - Also supports SDR ("Steam Datagram Relay") connections, which are // addressed by SteamID. There is a "P2P" use case and also a "hosted // dedicated server" use case. // //============================================================================= #ifndef ISTEAMNETWORKINGSOCKETS #define ISTEAMNETWORKINGSOCKETS #ifdef _WIN32 #pragma once #endif #include "steamnetworkingtypes.h" class ISteamNetworkingSocketsCallbacks; //----------------------------------------------------------------------------- /// Lower level networking interface that more closely mirrors the standard /// Berkeley sockets model. Sockets are hard! You should probably only use /// this interface under the existing circumstances: /// /// - You have an existing socket-based codebase you want to port, or coexist with. /// - You want to be able to connect based on IP address, rather than (just) Steam ID. /// - You need low-level control of bandwidth utilization, when to drop packets, etc. /// /// Note that neither of the terms "connection" and "socket" will correspond /// one-to-one with an underlying UDP socket. An attempt has been made to /// keep the semantics as similar to the standard socket model when appropriate, /// but some deviations do exist. class ISteamNetworkingSockets { public: /// Creates a "server" socket that listens for clients to connect to by /// calling ConnectByIPAddress, over ordinary UDP (IPv4 or IPv6) /// /// You must select a specific local port to listen on and set it /// the port field of the local address. /// /// Usually you wil set the IP portion of the address to zero, (SteamNetworkingIPAddr::Clear()). /// This means that you will not bind to any particular local interface. In addition, /// if possible the socket will be bound in "dual stack" mode, which means that it can /// accept both IPv4 and IPv6 clients. If you wish to bind a particular interface, then /// set the local address to the appropriate IPv4 or IPv6 IP. /// /// When a client attempts to connect, a SteamNetConnectionStatusChangedCallback_t /// will be posted. The connection will be in the connecting state. virtual HSteamListenSocket CreateListenSocketIP( const SteamNetworkingIPAddr *localAddress ) = 0; /// Creates a connection and begins talking to a "server" over UDP at the /// given IPv4 or IPv6 address. The remote host must be listening with a /// matching call to CreateListenSocketIP on the specified port. /// /// A SteamNetConnectionStatusChangedCallback_t callback will be triggered when we start /// connecting, and then another one on either timeout or successful connection. /// /// If the server does not have any identity configured, then their network address /// will be the only identity in use. Or, the network host may provide a platform-specific /// identity with or without a valid certificate to authenticate that identity. (These /// details will be contained in the SteamNetConnectionStatusChangedCallback_t.) It's /// up to your application to decide whether to allow the connection. /// /// By default, all connections will get basic encryption sufficient to prevent /// casual eavesdropping. But note that without certificates (or a shared secret /// distributed through some other out-of-band mechanism), you don't have any /// way of knowing who is actually on the other end, and thus are vulnerable to /// man-in-the-middle attacks. virtual HSteamNetConnection ConnectByIPAddress( const SteamNetworkingIPAddr *address ) = 0; #ifdef STEAMNETWORKINGSOCKETS_ENABLE_SDR /// Like CreateListenSocketIP, but clients will connect using ConnectP2P /// /// nVirtualPort specifies how clients can connect to this socket using /// ConnectP2P. It's very common for applications to only have one listening socket; /// in that case, use zero. If you need to open multiple listen sockets and have clients /// be able to connect to one or the other, then nVirtualPort should be a small integer (<1000) /// unique to each listen socket you create. /// /// If you use this, you probably want to call ISteamNetworkingUtils::InitializeRelayNetworkAccess() /// when your app initializes virtual HSteamListenSocket CreateListenSocketP2P( int nVirtualPort ) = 0; /// Begin connecting to a server that is identified using a platform-specific identifier. /// This requires some sort of third party rendezvous service, and will depend on the /// platform and what other libraries and services you are integrating with. /// /// At the time of this writing, there is only one supported rendezvous service: Steam. /// Set the SteamID (whether "user" or "gameserver") and Steam will determine if the /// client is online and facilitate a relay connection. Note that all P2P connections on /// Steam are currently relayed. /// /// If you use this, you probably want to call ISteamNetworkingUtils::InitializeRelayNetworkAccess() /// when your app initializes virtual HSteamNetConnection ConnectP2P( const SteamNetworkingIdentity *identityRemote, int nVirtualPort ) = 0; #endif /// Accept an incoming connection that has been received on a listen socket. /// /// When a connection attempt is received (perhaps after a few basic handshake /// packets have been exchanged to prevent trivial spoofing), a connection interface /// object is created in the k_ESteamNetworkingConnectionState_Connecting state /// and a SteamNetConnectionStatusChangedCallback_t is posted. At this point, your /// application MUST either accept or close the connection. (It may not ignore it.) /// Accepting the connection will transition it either into the connected state, /// or the finding route state, depending on the connection type. /// /// You should take action within a second or two, because accepting the connection is /// what actually sends the reply notifying the client that they are connected. If you /// delay taking action, from the client's perspective it is the same as the network /// being unresponsive, and the client may timeout the connection attempt. In other /// words, the client cannot distinguish between a delay caused by network problems /// and a delay caused by the application. /// /// This means that if your application goes for more than a few seconds without /// processing callbacks (for example, while loading a map), then there is a chance /// that a client may attempt to connect in that interval and fail due to timeout. /// /// If the application does not respond to the connection attempt in a timely manner, /// and we stop receiving communication from the client, the connection attempt will /// be timed out locally, transitioning the connection to the /// k_ESteamNetworkingConnectionState_ProblemDetectedLocally state. The client may also /// close the connection before it is accepted, and a transition to the /// k_ESteamNetworkingConnectionState_ClosedByPeer is also possible depending the exact /// sequence of events. /// /// Returns k_EResultInvalidParam if the handle is invalid. /// Returns k_EResultInvalidState if the connection is not in the appropriate state. /// (Remember that the connection state could change in between the time that the /// notification being posted to the queue and when it is received by the application.) virtual EResult AcceptConnection( HSteamNetConnection hConn ) = 0; /// Disconnects from the remote host and invalidates the connection handle. /// Any unread data on the connection is discarded. /// /// nReason is an application defined code that will be received on the other /// end and recorded (when possible) in backend analytics. The value should /// come from a restricted range. (See ESteamNetConnectionEnd.) If you don't need /// to communicate any information to the remote host, and do not want analytics to /// be able to distinguish "normal" connection terminations from "exceptional" ones, /// You may pass zero, in which case the generic value of /// k_ESteamNetConnectionEnd_App_Generic will be used. /// /// pszDebug is an optional human-readable diagnostic string that will be received /// by the remote host and recorded (when possible) in backend analytics. /// /// If you wish to put the socket into a "linger" state, where an attempt is made to /// flush any remaining sent data, use bEnableLinger=true. Otherwise reliable data /// is not flushed. /// /// If the connection has already ended and you are just freeing up the /// connection interface, the reason code, debug string, and linger flag are /// ignored. virtual bool CloseConnection( HSteamNetConnection hPeer, int nReason, const char *pszDebug, bool bEnableLinger ) = 0; /// Destroy a listen socket. All the connections that were accepting on the listen /// socket are closed ungracefully. virtual bool CloseListenSocket( HSteamListenSocket hSocket ) = 0; /// Set connection user data. the data is returned in the following places /// - You can query it using GetConnectionUserData. /// - The SteamNetworkingmessage_t structure. /// - The SteamNetConnectionInfo_t structure. (Which is a member of SteamNetConnectionStatusChangedCallback_t.) /// /// Returns false if the handle is invalid. virtual bool SetConnectionUserData( HSteamNetConnection hPeer, int64 nUserData ) = 0; /// Fetch connection user data. Returns -1 if handle is invalid /// or if you haven't set any userdata on the connection. virtual int64 GetConnectionUserData( HSteamNetConnection hPeer ) = 0; /// Set a name for the connection, used mostly for debugging virtual void SetConnectionName( HSteamNetConnection hPeer, const char *pszName ) = 0; /// Fetch connection name. Returns false if handle is invalid virtual bool GetConnectionName( HSteamNetConnection hPeer, char *pszName, int nMaxLen ) = 0; /// Send a message to the remote host on the specified connection. /// /// nSendFlags determines the delivery guarantees that will be provided, /// when data should be buffered, etc. E.g. k_nSteamNetworkingSend_Unreliable /// /// Note that the semantics we use for messages are not precisely /// the same as the semantics of a standard "stream" socket. /// (SOCK_STREAM) For an ordinary stream socket, the boundaries /// between chunks are not considered relevant, and the sizes of /// the chunks of data written will not necessarily match up to /// the sizes of the chunks that are returned by the reads on /// the other end. The remote host might read a partial chunk, /// or chunks might be coalesced. For the message semantics /// used here, however, the sizes WILL match. Each send call /// will match a successful read call on the remote host /// one-for-one. If you are porting existing stream-oriented /// code to the semantics of reliable messages, your code should /// work the same, since reliable message semantics are more /// strict than stream semantics. The only caveat is related to /// performance: there is per-message overhead to retain the /// message sizes, and so if your code sends many small chunks /// of data, performance will suffer. Any code based on stream /// sockets that does not write excessively small chunks will /// work without any changes. /// /// Returns: /// - k_EResultInvalidParam: invalid connection handle, or the individual message is too big. /// (See k_cbMaxSteamNetworkingSocketsMessageSizeSend) /// - k_EResultInvalidState: connection is in an invalid state /// - k_EResultNoConnection: connection has ended /// - k_EResultIgnored: You used k_nSteamNetworkingSend_NoDelay, and the message was dropped because /// we were not ready to send it. /// - k_EResultLimitExceeded: there was already too much data queued to be sent. /// (See k_ESteamNetworkingConfig_SendBufferSize) virtual EResult SendMessageToConnection( HSteamNetConnection hConn, const void *pData, uint32 cbData, int nSendFlags ) = 0; /// Flush any messages waiting on the Nagle timer and send them /// at the next transmission opportunity (often that means right now). /// /// If Nagle is enabled (it's on by default) then when calling /// SendMessageToConnection the message will be buffered, up to the Nagle time /// before being sent, to merge small messages into the same packet. /// (See k_ESteamNetworkingConfig_NagleTime) /// /// Returns: /// k_EResultInvalidParam: invalid connection handle /// k_EResultInvalidState: connection is in an invalid state /// k_EResultNoConnection: connection has ended /// k_EResultIgnored: We weren't (yet) connected, so this operation has no effect. virtual EResult FlushMessagesOnConnection( HSteamNetConnection hConn ) = 0; /// Fetch the next available message(s) from the connection, if any. /// Returns the number of messages returned into your array, up to nMaxMessages. /// If the connection handle is invalid, -1 is returned. /// /// The order of the messages returned in the array is relevant. /// Reliable messages will be received in the order they were sent (and with the /// same sizes --- see SendMessageToConnection for on this subtle difference from a stream socket). /// /// Unreliable messages may be dropped, or delivered out of order withrespect to /// each other or with respect to reliable messages. The same unreliable message /// may be received multiple times. /// /// If any messages are returned, you MUST call SteamNetworkingMessage_t::Release() on each /// of them free up resources after you are done. It is safe to keep the object alive for /// a little while (put it into some queue, etc), and you may call Release() from any thread. virtual int ReceiveMessagesOnConnection( HSteamNetConnection hConn, SteamNetworkingMessage_t **ppOutMessages, int nMaxMessages ) = 0; /// Same as ReceiveMessagesOnConnection, but will return the next message available /// on any connection that was accepted through the specified listen socket. Examine /// SteamNetworkingMessage_t::m_conn to know which client connection. /// /// Delivery order of messages among different clients is not defined. They may /// be returned in an order different from what they were actually received. (Delivery /// order of messages from the same client is well defined, and thus the order of the /// messages is relevant!) virtual int ReceiveMessagesOnListenSocket( HSteamListenSocket hSocket, SteamNetworkingMessage_t **ppOutMessages, int nMaxMessages ) = 0; /// Returns basic information about the high-level state of the connection. virtual bool GetConnectionInfo( HSteamNetConnection hConn, SteamNetConnectionInfo_t *pInfo ) = 0; /// Returns a small set of information about the real-time state of the connection /// Returns false if the connection handle is invalid, or the connection has ended. virtual bool GetQuickConnectionStatus( HSteamNetConnection hConn, SteamNetworkingQuickConnectionStatus *pStats ) = 0; /// Returns detailed connection stats in text format. Useful /// for dumping to a log, etc. /// /// Returns: /// -1 failure (bad connection handle) /// 0 OK, your buffer was filled in and '\0'-terminated /// >0 Your buffer was either nullptr, or it was too small and the text got truncated. /// Try again with a buffer of at least N bytes. virtual int GetDetailedConnectionStatus( HSteamNetConnection hConn, char *pszBuf, int cbBuf ) = 0; /// Returns local IP and port that a listen socket created using CreateListenSocketIP is bound to. /// /// An IPv6 address of ::0 means "any IPv4 or IPv6" /// An IPv6 address of ::ffff:0000:0000 means "any IPv4" virtual bool GetListenSocketAddress( HSteamListenSocket hSocket, SteamNetworkingIPAddr *address ) = 0; /// Create a pair of connections that are talking to each other, e.g. a loopback connection. /// This is very useful for testing, or so that your client/server code can work the same /// even when you are running a local "server". /// /// The two connections will immediately be placed into the connected state, and no callbacks /// will be posted immediately. After this, if you close either connection, the other connection /// will receive a callback, exactly as if they were communicating over the network. You must /// close *both* sides in order to fully clean up the resources! /// /// By default, internal buffers are used, completely bypassing the network, the chopping up of /// messages into packets, encryption, copying the payload, etc. This means that loopback /// packets, by default, will not simulate lag or loss. Passing true for bUseNetworkLoopback will /// cause the socket pair to send packets through the local network loopback device (127.0.0.1) /// on ephemeral ports. Fake lag and loss are supported in this case, and CPU time is expended /// to encrypt and decrypt. /// /// If you wish to assign a specific identity to either connection, you may pass a particular /// identity. Otherwise, if you pass nullptr, the respective connection will assume a generic /// "localhost" identity. If you use real network loopback, this might be translated to the /// actual bound loopback port. Otherwise, the port will be zero. virtual bool CreateSocketPair( HSteamNetConnection *pOutConnection1, HSteamNetConnection *pOutConnection2, bool bUseNetworkLoopback, const SteamNetworkingIdentity *pIdentity1, const SteamNetworkingIdentity *pIdentity2 ) = 0; /// Get the identity assigned to this interface. /// E.g. on Steam, this is the user's SteamID, or for the gameserver interface, the SteamID assigned /// to the gameserver. Returns false and sets the result to an invalid identity if we don't know /// our identity yet. (E.g. GameServer has not logged in. On Steam, the user will know their SteamID /// even if they are not signed into Steam.) virtual bool GetIdentity( SteamNetworkingIdentity *pIdentity ) = 0; #ifdef STEAMNETWORKINGSOCKETS_ENABLE_SDR // // Clients connecting to dedicated servers hosted in a data center, // using central-authority-granted tickets. // /// Call this when you receive a ticket from your backend / matchmaking system. Puts the /// ticket into a persistent cache, and optionally returns the parsed ticket. /// /// See stamdatagram_ticketgen.h for more details. virtual bool ReceivedRelayAuthTicket( const void *pvTicket, int cbTicket, SteamDatagramRelayAuthTicket *pOutParsedTicket ) = 0; /// Search cache for a ticket to talk to the server on the specified virtual port. /// If found, returns the number of seconds until the ticket expires, and optionally /// the complete cracked ticket. Returns 0 if we don't have a ticket. /// /// Typically this is useful just to confirm that you have a ticket, before you /// call ConnectToHostedDedicatedServer to connect to the server. virtual int FindRelayAuthTicketForServer( const SteamNetworkingIdentity *identityGameServer, int nVirtualPort, SteamDatagramRelayAuthTicket *pOutParsedTicket ) = 0; /// Client call to connect to a server hosted in a Valve data center, on the specified virtual /// port. You must have placed a ticket for this server into the cache, or else this connect attempt will fail! /// /// You may wonder why tickets are stored in a cache, instead of simply being passed as an argument /// here. The reason is to make reconnection to a gameserver robust, even if the client computer loses /// connection to Steam or the central backend, or the app is restarted or crashes, etc. /// /// If you use this, you probably want to call ISteamNetworkingUtils::InitializeRelayNetworkAccess() /// when your app initializes virtual HSteamNetConnection ConnectToHostedDedicatedServer( const SteamNetworkingIdentity *identityTarget, int nVirtualPort ) = 0; // // Servers hosted in Valve data centers // /// Returns the value of the SDR_LISTEN_PORT environment variable. This /// is the UDP server your server will be listening on. This will /// configured automatically for you in production environments. (You /// should set it yourself for testing.) virtual uint16 GetHostedDedicatedServerPort() = 0; /// If you are running in a production data center, this will return the data /// center code. Returns 0 otherwise. virtual SteamNetworkingPOPID GetHostedDedicatedServerPOPID() = 0; /// Return info about the hosted server. You will need to send this information to your /// backend, and put it in tickets, so that the relays will know how to forward traffic from /// clients to your server. See SteamDatagramRelayAuthTicket for more info. /// /// NOTE ABOUT DEVELOPMENT ENVIRONMENTS: /// In production in our data centers, these parameters are configured via environment variables. /// In development, the only one you need to set is SDR_LISTEN_PORT, which is the local port you /// want to listen on. Furthermore, if you are running your server behind a corporate firewall, /// you probably will not be able to put the routing information returned by this function into /// tickets. Instead, it should be a public internet address that the relays can use to send /// data to your server. So you might just end up hardcoding a public address and setup port /// forwarding on your corporate firewall. In that case, the port you put into the ticket /// needs to be the public-facing port opened on your firewall, if it is different from the /// actual server port. /// /// This function will fail if SteamDatagramServer_Init has not been called. /// /// Returns false if the SDR_LISTEN_PORT environment variable is not set. virtual bool GetHostedDedicatedServerAddress( SteamDatagramHostedAddress *pRouting ) = 0; /// Create a listen socket on the specified virtual port. The physical UDP port to use /// will be determined by the SDR_LISTEN_PORT environment variable. If a UDP port is not /// configured, this call will fail. /// /// Note that this call MUST be made through the SteamGameServerNetworkingSockets() interface virtual HSteamListenSocket CreateHostedDedicatedServerListenSocket( int nVirtualPort ) = 0; #endif // #ifndef STEAMNETWORKINGSOCKETS_ENABLE_SDR // Invoke all callbacks queued for this interface. // On Steam, callbacks are dispatched via the ordinary Steamworks callbacks mechanism. // So if you have code that is also targeting Steam, you should call this at about the // same time you would call SteamAPI_RunCallbacks and SteamGameServer_RunCallbacks. #ifdef STEAMNETWORKINGSOCKETS_STANDALONELIB virtual void RunCallbacks( ISteamNetworkingSocketsCallbacks *pCallbacks ) = 0; #endif protected: ~ISteamNetworkingSockets(); // Silence some warnings }; #define STEAMNETWORKINGSOCKETS_INTERFACE_VERSION "SteamNetworkingSockets002" extern "C" { // Global accessor. #if defined( STEAMNETWORKINGSOCKETS_PARTNER ) // Standalone lib. Use different symbol name, so that we can dynamically switch between steamclient.dll // and the standalone lib STEAMNETWORKINGSOCKETS_INTERFACE ISteamNetworkingSockets *SteamNetworkingSockets_Lib(); STEAMNETWORKINGSOCKETS_INTERFACE ISteamNetworkingSockets *SteamGameServerNetworkingSockets_Lib(); inline ISteamNetworkingSockets *SteamNetworkingSockets() { return SteamNetworkingSockets_Lib(); } inline ISteamNetworkingSockets *SteamGameServerNetworkingSockets() { return SteamGameServerNetworkingSockets_Lib(); } #elif defined( STEAMNETWORKINGSOCKETS_OPENSOURCE ) // Opensource GameNetworkingSockets STEAMNETWORKINGSOCKETS_INTERFACE ISteamNetworkingSockets *SteamNetworkingSockets(); #else // Steamworks SDK inline ISteamNetworkingSockets *SteamNetworkingSockets(); STEAM_DEFINE_USER_INTERFACE_ACCESSOR( ISteamNetworkingSockets *, SteamNetworkingSockets, STEAMNETWORKINGSOCKETS_INTERFACE_VERSION ); inline ISteamNetworkingSockets *SteamGameServerNetworkingSockets(); STEAM_DEFINE_GAMESERVER_INTERFACE_ACCESSOR( ISteamNetworkingSockets *, SteamGameServerNetworkingSockets, STEAMNETWORKINGSOCKETS_INTERFACE_VERSION ); #endif } /// Callback struct used to notify when a connection has changed state #if defined( VALVE_CALLBACK_PACK_SMALL ) #pragma pack( push, 4 ) #elif defined( VALVE_CALLBACK_PACK_LARGE ) #pragma pack( push, 8 ) #else #error "Must define VALVE_CALLBACK_PACK_SMALL or VALVE_CALLBACK_PACK_LARGE" #endif /// This callback is posted whenever a connection is created, destroyed, or changes state. /// The m_info field will contain a complete description of the connection at the time the /// change occurred and the callback was posted. In particular, m_eState will have the /// new connection state. /// /// You will usually need to listen for this callback to know when: /// - A new connection arrives on a listen socket. /// m_info.m_hListenSocket will be set, m_eOldState = k_ESteamNetworkingConnectionState_None, /// and m_info.m_eState = k_ESteamNetworkingConnectionState_Connecting. /// See ISteamNetworkigSockets::AcceptConnection. /// - A connection you initiated has been accepted by the remote host. /// m_eOldState = k_ESteamNetworkingConnectionState_Connecting, and /// m_info.m_eState = k_ESteamNetworkingConnectionState_Connected. /// Some connections might transition to k_ESteamNetworkingConnectionState_FindingRoute first. /// - A connection has been actively rejected or closed by the remote host. /// m_eOldState = k_ESteamNetworkingConnectionState_Connecting or k_ESteamNetworkingConnectionState_Connected, /// and m_info.m_eState = k_ESteamNetworkingConnectionState_ClosedByPeer. m_info.m_eEndReason /// and m_info.m_szEndDebug will have for more details. /// NOTE: upon receiving this callback, you must still destroy the connection using /// ISteamNetworkingSockets::CloseConnection to free up local resources. (The details /// passed to the function are not used in this case, since the connection is already closed.) /// - A problem was detected with the connection, and it has been closed by the local host. /// The most common failure is timeout, but other configuration or authentication failures /// can cause this. m_eOldState = k_ESteamNetworkingConnectionState_Connecting or /// k_ESteamNetworkingConnectionState_Connected, and m_info.m_eState = k_ESteamNetworkingConnectionState_ProblemDetectedLocally. /// m_info.m_eEndReason and m_info.m_szEndDebug will have for more details. /// NOTE: upon receiving this callback, you must still destroy the connection using /// ISteamNetworkingSockets::CloseConnection to free up local resources. (The details /// passed to the function are not used in this case, since the connection is already closed.) /// /// Remember that callbacks are posted to a queue, and networking connections can /// change at any time. It is possible that the connection has already changed /// state by the time you process this callback. /// /// Also note that callbacks will be posted when connections are created and destroyed by your own API calls. struct SteamNetConnectionStatusChangedCallback_t { enum { k_iCallback = k_iSteamNetworkingSocketsCallbacks + 1 }; /// Connection handle HSteamNetConnection m_hConn; /// Full connection info SteamNetConnectionInfo_t m_info; /// Previous state. (Current state is in m_info.m_eState) ESteamNetworkingConnectionState m_eOldState; }; #pragma pack( pop ) #endif // ISTEAMNETWORKINGSOCKETS