/
client.go
280 lines (232 loc) · 6.34 KB
/
client.go
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package xmpp
import (
"crypto/tls"
"encoding/xml"
"errors"
"fmt"
"log"
)
// Config structure used to create a new XMPP client connection.
type ClientConfig struct {
// Don't upgrade the connection to TLS, even if the server supports it. If
// the server *requires* TLS then this option is ignored.
NoTLS bool
// Skip verification of the server's certificate chain. Probably only
// useful during development.
InsecureSkipVerify bool
}
// Create a client XMPP over the stream.
func NewClientXMPP(stream *Stream, jid JID, password string, config *ClientConfig) (*XMPP, error) {
if config == nil {
config = &ClientConfig{}
}
for {
if err := startClient(stream, jid); err != nil {
return nil, err
}
// Read features.
f := new(features)
if err := stream.Decode(f, nil); err != nil {
return nil, err
}
// TLS?
if f.StartTLS != nil && (f.StartTLS.Required != nil || !config.NoTLS) {
log.Println("Start TLS")
if err := startTLS(stream, config); err != nil {
return nil, err
}
continue // Restart
}
// Authentication
if f.Mechanisms != nil {
log.Println("Authenticating")
if err := authenticate(stream, f.Mechanisms.Mechanisms, jid.Node, password); err != nil {
return nil, err
}
continue // Restart
}
// Bind resource.
if f.Bind != nil {
log.Println("Binding resource.")
boundJID, err := bindResource(stream, jid)
if err != nil {
return nil, err
}
jid = boundJID
}
// Session.
if f.Session != nil {
log.Println("Establishing session.")
if err := establishSession(stream, jid.Domain); err != nil {
return nil, err
}
}
break
}
return newXMPP(jid, stream), nil
}
func startClient(stream *Stream, jid JID) error {
start := xml.StartElement{
xml.Name{"stream", "stream"},
[]xml.Attr{
xml.Attr{xml.Name{"", "xmlns"}, nsClient},
xml.Attr{xml.Name{"xmlns", "stream"}, nsStreams},
xml.Attr{xml.Name{"", "from"}, jid.Full()},
xml.Attr{xml.Name{"", "to"}, jid.Domain},
xml.Attr{xml.Name{"", "version"}, "1.0"},
},
}
rstart, err := stream.SendStart(&start)
if err != nil {
return err
}
if rstart.Name != (xml.Name{nsStreams, "stream"}) {
return fmt.Errorf("unexpected start element: %s", rstart.Name)
}
return nil
}
func startTLS(stream *Stream, config *ClientConfig) error {
if err := stream.Send(&tlsStart{}); err != nil {
return err
}
p := tlsProceed{}
if err := stream.Decode(&p, nil); err != nil {
return err
}
tlsConfig := tls.Config{InsecureSkipVerify: config.InsecureSkipVerify, ServerName: stream.config.ConnectionDomain}
return stream.UpgradeTLS(&tlsConfig)
}
type tlsStart struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls starttls"`
}
type tlsProceed struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls proceed"`
}
func authenticate(stream *Stream, mechanisms []string, user, password string) error {
for _, handler := range authHandlers {
if !stringSliceContains(mechanisms, handler.Mechanism) {
continue
}
if err := handler.Fn(stream, user, password); err == nil {
log.Printf("Authentication (%s) successful", handler.Mechanism)
return nil
}
}
return errors.New("no supported SASL mechanism found")
}
type authHandler struct {
Mechanism string
Fn func(*Stream, string, string) error
}
var authHandlers = []authHandler{
{"PLAIN", authenticatePlain},
}
func authenticatePlain(stream *Stream, user, password string) error {
auth := saslAuth{Mechanism: "PLAIN", Text: saslEncodePlain(user, password)}
if err := stream.Send(&auth); err != nil {
return err
}
return authenticateResponse(stream)
}
func authenticateResponse(stream *Stream) error {
se, err := stream.Next()
if err != nil {
return err
}
switch se.Name.Local {
case "success":
if err := stream.Skip(); err != nil {
return err
}
return nil
case "failure":
f := new(saslFailure)
if err := stream.Decode(f, se); err != nil {
return err
}
return fmt.Errorf("Authentication failed: %s", f.Reason.Local)
default:
return fmt.Errorf("Unexpected: %s", se.Name)
}
}
type saslAuth struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl auth"`
Mechanism string `xml:"mechanism,attr"`
Text string `xml:",chardata"`
}
func bindResource(stream *Stream, jid JID) (JID, error) {
req := IQ{ID: UUID4(), Type: "set"}
if jid.Resource == "" {
req.PayloadEncode(bindIQ{})
} else {
req.PayloadEncode(bindIQ{Resource: jid.Resource})
}
if err := stream.Send(req); err != nil {
return JID{}, err
}
resp := IQ{}
err := stream.Decode(&resp, nil)
if err != nil {
return JID{}, err
}
bindResp := bindIQ{}
resp.PayloadDecode(&bindResp)
boundJID, err := ParseJID(bindResp.JID)
return boundJID, nil
}
type bindIQ struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-bind bind"`
Resource string `xml:"resource,omitempty"`
JID string `xml:"jid,omitempty"`
}
func establishSession(stream *Stream, domain string) error {
req := IQ{ID: UUID4(), Type: "set", To: domain}
req.PayloadEncode(&session{})
if err := stream.Send(req); err != nil {
return err
}
resp := IQ{}
if err := stream.Decode(&resp, nil); err != nil {
return err
} else if resp.Error != nil {
return resp.Error
}
return nil
}
func stringSliceContains(l []string, m string) bool {
for _, i := range l {
if i == m {
return true
}
}
return false
}
type features struct {
XMLName xml.Name `xml:"http://etherx.jabber.org/streams features"`
StartTLS *tlsStartTLS `xml:"starttls"`
Mechanisms *mechanisms `xml:"mechanisms"`
Bind *bind `xml:"bind"`
Session *session `xml:"session"`
}
type session struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-session session"`
}
type bind struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-bind bind"`
Required *required `xml:"required"`
}
type mechanisms struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl mechanisms"`
Mechanisms []string `xml:"mechanism"`
}
type tlsStartTLS struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls starttls"`
Required *required `xml:"required"`
}
type required struct{}
type saslFailure struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl failure"`
Reason xml.Name `xml:",any"`
}
// BUG(matt): authentication incorrectly reports, "No supported SASL mechanism
// found", for authentication attemtps that fail due to invalid credentials.