package xmpp import ( "context" "encoding/xml" "errors" "io" "net" "sync" "time" "gosrc.io/xmpp/stanza" ) //============================================================================= // EventManager // SyncConnState represents the current connection state. type SyncConnState struct { sync.RWMutex // Current state of the client. Please use the dedicated getter and setter for this field as they are thread safe. state ConnState } type ConnState = uint8 // getState is a thread-safe getter for the current state func (scs *SyncConnState) getState() ConnState { var res ConnState scs.RLock() res = scs.state scs.RUnlock() return res } // setState is a thread-safe setter for the current func (scs *SyncConnState) setState(cs ConnState) { scs.Lock() scs.state = cs scs.Unlock() } // This is a the list of events happening on the connection that the // client can be notified about. const ( InitialPresence = "" StateDisconnected ConnState = iota StateResuming StateSessionEstablished StateStreamError StatePermanentError ) // Event is a structure use to convey event changes related to client state. This // is for example used to notify the client when the client get disconnected. type Event struct { State SyncConnState Description string StreamError string SMState SMState } // SMState holds Stream Management information regarding the session that can be // used to resume session after disconnect type SMState struct { // Stream Management ID Id string // Inbound stanza count Inbound uint // IP affinity preferredReconAddr string // Error StreamErrorGroup stanza.StanzaErrorGroup // Track sent stanzas *stanza.UnAckQueue // TODO Store max and timestamp, to check if we should retry resumption or not } // EventHandler is use to pass events about state of the connection to // client implementation. type EventHandler func(Event) error type EventManager struct { // Store current state. Please use "getState" and "setState" to access and/or modify this. CurrentState SyncConnState // Callback used to propagate connection state changes Handler EventHandler } // updateState changes the CurrentState in the event manager. The state read is threadsafe but there is no guarantee // regarding the triggered callback function. func (em *EventManager) updateState(state ConnState) { em.CurrentState.setState(state) if em.Handler != nil { em.Handler(Event{State: em.CurrentState}) } } // disconnected changes the CurrentState in the event manager to "disconnected". The state read is threadsafe but there is no guarantee // regarding the triggered callback function. func (em *EventManager) disconnected(state SMState) { em.CurrentState.setState(StateDisconnected) if em.Handler != nil { em.Handler(Event{State: em.CurrentState, SMState: state}) } } // streamError changes the CurrentState in the event manager to "streamError". The state read is threadsafe but there is no guarantee // regarding the triggered callback function. func (em *EventManager) streamError(error, desc string) { em.CurrentState.setState(StateStreamError) if em.Handler != nil { em.Handler(Event{State: em.CurrentState, StreamError: error, Description: desc}) } } // Client // ============================================================================ var ErrCanOnlySendGetOrSetIq = errors.New("SendIQ can only send get and set IQ stanzas") // Client is the main structure used to connect as a client on an XMPP // server. type Client struct { // Store user defined options and states config *Config // Session gather data that can be accessed by users of this library Session *Session transport Transport // Router is used to dispatch packets router *Router // Track and broadcast connection state EventManager // Handle errors from client execution ErrorHandler func(error) // Post connection hook. This will be executed on first connection PostConnectHook func() error // Post resume hook. This will be executed after the client resumes a lost connection using StreamManagement (XEP-0198) PostResumeHook func() error } /* Setting up the client / Checking the parameters */ // NewClient generates a new XMPP client, based on Config passed as parameters. // If host is not specified, the DNS SRV should be used to find the host from the domain part of the Jid. // Default the port to 5222. func NewClient(config *Config, r *Router, errorHandler func(error)) (c *Client, err error) { if config.KeepaliveInterval == 0 { config.KeepaliveInterval = time.Second * 30 } // Parse Jid if config.parsedJid, err = stanza.NewJid(config.Jid); err != nil { err = errors.New("missing jid") return nil, NewConnError(err, true) } if config.Credential.secret == "" { err = errors.New("missing credential") return nil, NewConnError(err, true) } // Fallback to jid domain if config.Address == "" { config.Address = config.parsedJid.Domain // Fetch SRV DNS-Entries _, srvEntries, err := net.LookupSRV("xmpp-client", "tcp", config.parsedJid.Domain) if err == nil && len(srvEntries) > 0 { // If we found matching DNS records, use the entry with highest weight bestSrv := srvEntries[0] for _, srv := range srvEntries { if srv.Priority <= bestSrv.Priority && srv.Weight >= bestSrv.Weight { bestSrv = srv config.Address = ensurePort(srv.Target, int(srv.Port)) } } } } if config.Domain == "" { // Fallback to jid domain config.Domain = config.parsedJid.Domain } c = new(Client) c.config = config c.router = r c.ErrorHandler = errorHandler if c.config.ConnectTimeout == 0 { c.config.ConnectTimeout = 15 // 15 second as default } if config.TransportConfiguration.Domain == "" { config.TransportConfiguration.Domain = config.parsedJid.Domain } c.config.TransportConfiguration.ConnectTimeout = c.config.ConnectTimeout c.transport = NewClientTransport(c.config.TransportConfiguration) if config.StreamLogger != nil { c.transport.LogTraffic(config.StreamLogger) } return } // Connect establishes a first time connection to a XMPP server. // It calls the PostConnectHook func (c *Client) Connect() error { err := c.connect() if err != nil { return err } // TODO: Do we always want to send initial presence automatically ? // Do we need an option to avoid that or do we rely on client to send the presence itself ? err = c.sendWithWriter(c.transport, []byte(InitialPresence)) // Execute the post first connection hook. Typically this holds "ask for roster" and this type of actions. if c.PostConnectHook != nil { err = c.PostConnectHook() if err != nil { return err } } // Start the keepalive go routine keepaliveQuit := make(chan struct{}) go keepalive(c.transport, c.config.KeepaliveInterval, keepaliveQuit) // Start the receiver go routine go c.recv(keepaliveQuit) return err } // connect establishes an actual TCP connection, based on previously defined parameters, as well as a XMPP session func (c *Client) connect() error { var state SMState var err error // This is the TCP connection streamId, err := c.transport.Connect() if err != nil { return err } // Client is ok, we now open XMPP session with TLS negotiation if possible and session resume or binding // depending on state. if c.Session, err = NewSession(c, state); err != nil { // Try to get the stream close tag from the server. go func() { for { val, err := stanza.NextPacket(c.transport.GetDecoder()) if err != nil { c.ErrorHandler(err) c.disconnected(state) return } switch val.(type) { case stanza.StreamClosePacket: // TCP messages should arrive in order, so we can expect to get nothing more after this occurs c.transport.ReceivedStreamClose() return } } }() c.Disconnect() return err } c.Session.StreamId = streamId c.updateState(StateSessionEstablished) return err } // Resume attempts resuming a Stream Managed session, based on the provided stream management // state. See XEP-0198 func (c *Client) Resume() error { c.EventManager.updateState(StateResuming) err := c.connect() if err != nil { return err } // Execute post reconnect hook. This can be different from the first connection hook, and not trigger roster retrival // for example. if c.PostResumeHook != nil { err = c.PostResumeHook() } return err } // Disconnect disconnects the client from the server, sending a stream close nonza and closing the TCP connection. func (c *Client) Disconnect() error { if c.transport != nil { return c.transport.Close() } // No transport so no connection. return nil } func (c *Client) SetHandler(handler EventHandler) { c.Handler = handler } // Send marshals XMPP stanza and sends it to the server. func (c *Client) Send(packet stanza.Packet) error { conn := c.transport if conn == nil { return errors.New("client is not connected") } data, err := xml.Marshal(packet) if err != nil { return errors.New("cannot marshal packet " + err.Error()) } // Store stanza as non-acked as part of stream management // See https://xmpp.org/extensions/xep-0198.html#scenarios if c.config.StreamManagementEnable { if _, ok := packet.(stanza.SMRequest); !ok { toStore := stanza.UnAckedStz{Stz: string(data)} c.Session.SMState.UnAckQueue.Push(&toStore) } } return c.sendWithWriter(c.transport, data) } // SendIQ sends an IQ set or get stanza to the server. If a result is received // the provided handler function will automatically be called. // // The provided context should have a timeout to prevent the client from waiting // forever for an IQ result. For example: // // ctx, _ := context.WithTimeout(context.Background(), 30 * time.Second) // result := <- client.SendIQ(ctx, iq) // func (c *Client) SendIQ(ctx context.Context, iq *stanza.IQ) (chan stanza.IQ, error) { if iq.Attrs.Type != stanza.IQTypeSet && iq.Attrs.Type != stanza.IQTypeGet { return nil, ErrCanOnlySendGetOrSetIq } if err := c.Send(iq); err != nil { return nil, err } return c.router.NewIQResultRoute(ctx, iq.Attrs.Id), nil } // SendRaw sends an XMPP stanza as a string to the server. // It can be invalid XML or XMPP content. In that case, the server will // disconnect the client. It is up to the user of this method to // carefully craft the XML content to produce valid XMPP. func (c *Client) SendRaw(packet string) error { conn := c.transport if conn == nil { return errors.New("client is not connected") } // Store stanza as non-acked as part of stream management // See https://xmpp.org/extensions/xep-0198.html#scenarios if c.config.StreamManagementEnable { toStore := stanza.UnAckedStz{Stz: packet} c.Session.SMState.UnAckQueue.Push(&toStore) } return c.sendWithWriter(c.transport, []byte(packet)) } func (c *Client) sendWithWriter(writer io.Writer, packet []byte) error { var err error _, err = writer.Write(packet) return err } // ============================================================================ // Go routines // Loop: Receive data from server func (c *Client) recv(keepaliveQuit chan<- struct{}) { for { val, err := stanza.NextPacket(c.transport.GetDecoder()) if err != nil { c.ErrorHandler(err) close(keepaliveQuit) c.disconnected(c.Session.SMState) return } // Handle stream errors switch packet := val.(type) { case stanza.StreamError: c.router.route(c, val) close(keepaliveQuit) c.streamError(packet.Error.Local, packet.Text) c.ErrorHandler(errors.New("stream error: " + packet.Error.Local)) // We don't return here, because we want to wait for the stream close tag from the server, or timeout. c.Disconnect() // Process Stream management nonzas case stanza.SMRequest: answer := stanza.SMAnswer{XMLName: xml.Name{ Space: stanza.NSStreamManagement, Local: "a", }, H: c.Session.SMState.Inbound} err = c.Send(answer) if err != nil { c.ErrorHandler(err) return } case stanza.StreamClosePacket: // TCP messages should arrive in order, so we can expect to get nothing more after this occurs c.transport.ReceivedStreamClose() return default: c.Session.SMState.Inbound++ } // Do normal route processing in a go-routine so we can immediately // start receiving other stanzas. This also allows route handlers to // send and receive more stanzas. go c.router.route(c, val) } } // Loop: send whitespace keepalive to server // This is use to keep the connection open, but also to detect connection loss // and trigger proper client connection shutdown. func keepalive(transport Transport, interval time.Duration, quit <-chan struct{}) { ticker := time.NewTicker(interval) for { select { case <-ticker.C: if err := transport.Ping(); err != nil { // When keepalive fails, we force close the transport. In all cases, the recv will also fail. ticker.Stop() _ = transport.Close() return } case <-quit: ticker.Stop() return } } }