go-xmpp/session.go
2019-06-07 15:23:23 +02:00

194 lines
4.8 KiB
Go

package xmpp // import "gosrc.io/xmpp"
import (
"crypto/tls"
"encoding/xml"
"errors"
"fmt"
"io"
"net"
)
const xmppStreamOpen = "<?xml version='1.0'?><stream:stream to='%s' xmlns='%s' xmlns:stream='%s' version='1.0'>"
type Session struct {
// Session info
BindJid string // Jabber ID as provided by XMPP server
StreamId string
Features StreamFeatures
TlsEnabled bool
lastPacketId int
// Session interface
In chan interface{}
Out chan interface{}
// read / write
socketProxy io.ReadWriter
decoder *xml.Decoder
// error management
err error
}
func NewSession(conn net.Conn, o Config) (net.Conn, *Session, error) {
s := new(Session)
s.init(conn, o)
// starttls
var tlsConn net.Conn
tlsConn = s.startTlsIfSupported(conn, o.parsedJid.domain)
if s.TlsEnabled {
s.reset(conn, tlsConn, o)
}
if !s.TlsEnabled && !o.Insecure {
return nil, nil, NewConnError(errors.New("failed to negotiate TLS session"), true)
}
// auth
s.auth(o)
s.reset(tlsConn, tlsConn, o)
// bind resource and 'start' XMPP session
s.bind(o)
s.rfc3921Session(o)
return tlsConn, s, s.err
}
func (s *Session) PacketId() string {
s.lastPacketId++
return fmt.Sprintf("%x", s.lastPacketId)
}
func (s *Session) init(conn net.Conn, o Config) {
s.setProxy(nil, conn, o)
s.Features = s.open(o.parsedJid.domain)
}
func (s *Session) reset(conn net.Conn, newConn net.Conn, o Config) {
if s.err != nil {
return
}
s.setProxy(conn, newConn, o)
s.Features = s.open(o.parsedJid.domain)
}
// TODO: setProxyLogger ? better name ? This is not a TCP / HTTP proxy
func (s *Session) setProxy(conn net.Conn, newConn net.Conn, o Config) {
if newConn != conn {
s.socketProxy = newSocketProxy(newConn, o.PacketLogger)
}
s.decoder = xml.NewDecoder(s.socketProxy)
s.decoder.CharsetReader = o.CharsetReader
}
func (s *Session) open(domain string) (f StreamFeatures) {
// Send stream open tag
if _, s.err = fmt.Fprintf(s.socketProxy, xmppStreamOpen, domain, NSClient, NSStream); s.err != nil {
return
}
// Set xml decoder and extract streamID from reply
s.StreamId, s.err = initDecoder(s.decoder) // TODO refactor / rename
if s.err != nil {
return
}
// extract stream features
if s.err = s.decoder.Decode(&f); s.err != nil {
s.err = errors.New("stream open decode features: " + s.err.Error())
}
return
}
func (s *Session) startTlsIfSupported(conn net.Conn, domain string) net.Conn {
if s.err != nil {
return conn
}
if s.Features.StartTLS.XMLName.Space+" "+s.Features.StartTLS.XMLName.Local == nsTLS+" starttls" {
fmt.Fprintf(s.socketProxy, "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>")
var k tlsProceed
if s.err = s.decoder.DecodeElement(&k, nil); s.err != nil {
s.err = errors.New("expecting starttls proceed: " + s.err.Error())
return conn
}
s.TlsEnabled = true
// TODO: add option to accept all TLS certificates: insecureSkipTlsVerify (DefaultTlsConfig.InsecureSkipVerify)
DefaultTlsConfig.ServerName = domain
tlsConn := tls.Client(conn, &DefaultTlsConfig)
// We convert existing connection to TLS
if s.err = tlsConn.Handshake(); s.err != nil {
return tlsConn
}
// We check that cert matches hostname
s.err = tlsConn.VerifyHostname(domain)
return tlsConn
}
// starttls is not supported => we do not upgrade the connection:
return conn
}
func (s *Session) auth(o Config) {
if s.err != nil {
return
}
s.err = authSASL(s.socketProxy, s.decoder, s.Features, o.parsedJid.username, o.Password)
}
func (s *Session) bind(o Config) {
if s.err != nil {
return
}
// Send IQ message asking to bind to the local user name.
var resource = o.parsedJid.resource
if resource != "" {
fmt.Fprintf(s.socketProxy, "<iq type='set' id='%s'><bind xmlns='%s'><resource>%s</resource></bind></iq>",
s.PacketId(), nsBind, resource)
} else {
fmt.Fprintf(s.socketProxy, "<iq type='set' id='%s'><bind xmlns='%s'/></iq>", s.PacketId(), nsBind)
}
var iq IQ
if s.err = s.decoder.Decode(&iq); s.err != nil {
s.err = errors.New("error decoding iq bind result: " + s.err.Error())
return
}
// TODO Check all elements
switch payload := iq.Payload[0].(type) {
case *BindBind:
s.BindJid = payload.Jid // our local id (with possibly randomly generated resource
default:
s.err = errors.New("iq bind result missing")
}
return
}
// TODO: remove when ejabberd is fixed: https://github.com/processone/ejabberd/issues/869
// After the bind, if the session is required (as per old RFC 3921), we send the session open iq
func (s *Session) rfc3921Session(o Config) {
if s.err != nil {
return
}
var iq IQ
if s.Features.Session.optional.Local != "" {
fmt.Fprintf(s.socketProxy, "<iq type='set' id='%s'><session xmlns='%s'/></iq>", s.PacketId(), nsSession)
if s.err = s.decoder.Decode(&iq); s.err != nil {
s.err = errors.New("expecting iq result after session open: " + s.err.Error())
return
}
}
}