package xmpp import ( "crypto/sha1" "encoding/hex" "encoding/xml" "errors" "fmt" "io" "net" "time" ) const componentStreamOpen = "<?xml version='1.0'?><stream:stream to='%s' xmlns='%s' xmlns:stream='%s'>" type ComponentOptions struct { // ================================= // Component Connection Info // Domain is the XMPP server subdomain that the component will handle Domain string // Secret is the "password" used by the XMPP server to secure component access Secret string // Address is the XMPP Host and port to connect to. Host is of // the form 'serverhost:port' i.e "localhost:8888" Address string // ================================= // Component discovery // Component human readable name, that will be shown in XMPP discovery Name string // Typical categories and types: https://xmpp.org/registrar/disco-categories.html Category string Type string // ================================= // Communication with developer client / StreamManager // Track and broadcast connection state EventManager } // Component implements an XMPP extension allowing to extend XMPP server // using external components. Component specifications are defined // in XEP-0114, XEP-0355 and XEP-0356. type Component struct { ComponentOptions router *Router // TCP level connection conn net.Conn // read / write socketProxy io.ReadWriter // TODO decoder *xml.Decoder } func NewComponent(opts ComponentOptions, r *Router) (*Component, error) { c := Component{ComponentOptions: opts, router: r} return &c, nil } // Connect triggers component connection to XMPP server component port. // TODO: Failed handshake should be a permanent error func (c *Component) Connect() error { var conn net.Conn var err error if conn, err = net.DialTimeout("tcp", c.Address, time.Duration(5)*time.Second); err != nil { return err } c.conn = conn // 1. Send stream open tag if _, err := fmt.Fprintf(conn, componentStreamOpen, c.Domain, NSComponent, NSStream); err != nil { return errors.New("cannot send stream open " + err.Error()) } c.decoder = xml.NewDecoder(conn) // 2. Initialize xml decoder and extract streamID from reply streamId, err := initStream(c.decoder) if err != nil { return errors.New("cannot init decoder " + err.Error()) } // 3. Authentication if _, err := fmt.Fprintf(conn, "<handshake>%s</handshake>", c.handshake(streamId)); err != nil { return errors.New("cannot send handshake " + err.Error()) } // 4. Check server response for authentication val, err := nextPacket(c.decoder) if err != nil { return err } switch v := val.(type) { case StreamError: return errors.New("handshake failed " + v.Error.Local) case Handshake: // Start the receiver go routine go c.recv() return nil default: return errors.New("expecting handshake result, got " + v.Name()) } } func (c *Component) Disconnect() { _ = c.SendRaw("</stream:stream>") // TODO: Add a way to wait for stream close acknowledgement from the server for clean disconnect _ = c.conn.Close() } func (c *Component) SetHandler(handler EventHandler) { c.Handler = handler } // Receiver Go routine receiver func (c *Component) recv() (err error) { for { val, err := nextPacket(c.decoder) if err != nil { c.updateState(StateDisconnected) return err } // Handle stream errors switch p := val.(type) { case StreamError: c.router.Route(c, val) c.streamError(p.Error.Local, p.Text) return errors.New("stream error: " + p.Error.Local) } c.router.Route(c, val) } } // Send marshalls XMPP stanza and sends it to the server. func (c *Component) Send(packet Packet) error { data, err := xml.Marshal(packet) if err != nil { return errors.New("cannot marshal packet " + err.Error()) } if _, err := fmt.Fprintf(c.conn, string(data)); err != nil { return errors.New("cannot send packet " + err.Error()) } return 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 component. It is up to the user of this method to // carefully craft the XML content to produce valid XMPP. func (c *Component) SendRaw(packet string) error { var err error _, err = fmt.Fprintf(c.conn, packet) return err } // handshake generates an authentication token based on StreamID and shared secret. func (c *Component) handshake(streamId string) string { // 1. Concatenate the Stream ID received from the server with the shared secret. concatStr := streamId + c.Secret // 2. Hash the concatenated string according to the SHA1 algorithm, i.e., SHA1( concat (sid, password)). h := sha1.New() h.Write([]byte(concatStr)) hash := h.Sum(nil) // 3. Ensure that the hash output is in hexadecimal format, not binary or base64. // 4. Convert the hash output to all lowercase characters. encodedStr := hex.EncodeToString(hash) return encodedStr } // ============================================================================ // Handshake Stanza // Handshake is a stanza used by XMPP components to authenticate on XMPP // component port. type Handshake struct { XMLName xml.Name `xml:"jabber:component:accept handshake"` // TODO Add handshake value with test for proper serialization // Value string `xml:",innerxml"` } func (Handshake) Name() string { return "component:handshake" } // Handshake decoding wrapper type handshakeDecoder struct{} var handshake handshakeDecoder func (handshakeDecoder) decode(p *xml.Decoder, se xml.StartElement) (Handshake, error) { var packet Handshake err := p.DecodeElement(&packet, &se) return packet, err } // ============================================================================ // Component delegation // XEP-0355 // Delegation can be used both on message (for delegated) and IQ (for Forwarded), // depending on the context. type Delegation struct { MsgExtension XMLName xml.Name `xml:"urn:xmpp:delegation:1 delegation"` Forwarded *Forwarded // This is used in iq to wrap delegated iqs Delegated *Delegated // This is used in a message to confirm delegated namespace } func (d *Delegation) Namespace() string { return d.XMLName.Space } type Forwarded struct { XMLName xml.Name `xml:"urn:xmpp:forward:0 forwarded"` Stanza Packet } // UnmarshalXML is a custom unmarshal function used by xml.Unmarshal to // transform generic XML content into hierarchical Node structure. func (f *Forwarded) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error { // Check subelements to extract required field as boolean for { t, err := d.Token() if err != nil { return err } switch tt := t.(type) { case xml.StartElement: if packet, err := decodeClient(d, tt); err == nil { f.Stanza = packet } case xml.EndElement: if tt == start.End() { return nil } } } } type Delegated struct { XMLName xml.Name `xml:"delegated"` Namespace string `xml:"namespace,attr,omitempty"` } func init() { TypeRegistry.MapExtension(PKTMessage, xml.Name{"urn:xmpp:delegation:1", "delegation"}, Delegation{}) TypeRegistry.MapExtension(PKTIQ, xml.Name{"urn:xmpp:delegation:1", "delegation"}, Delegation{}) } /* TODO: Add support for discovery management directly in component TODO: Support multiple identities on disco info TODO: Support returning features on disco info */