Moving XMPP library to Fluux project

auth.go

@@ -0,0 +1,87 @@
+package xmpp // import "fluux.io/xmpp"
+
+import (
+	"encoding/base64"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"io"
+)
+
+func authSASL(socket io.ReadWriter, decoder *xml.Decoder, f streamFeatures, user string, password string) (err error) {
+	// TODO: Implement other type of SASL Authentication
+	havePlain := false
+	for _, m := range f.Mechanisms.Mechanism {
+		if m == "PLAIN" {
+			havePlain = true
+			break
+		}
+	}
+	if !havePlain {
+		return fmt.Errorf("PLAIN authentication is not supported by server: %v", f.Mechanisms.Mechanism)
+	}
+
+	return authPlain(socket, decoder, user, password)
+}
+
+// Plain authentication: send base64-encoded \x00 user \x00 password
+func authPlain(socket io.ReadWriter, decoder *xml.Decoder, user string, password string) error {
+	raw := "\x00" + user + "\x00" + password
+	enc := make([]byte, base64.StdEncoding.EncodedLen(len(raw)))
+	base64.StdEncoding.Encode(enc, []byte(raw))
+	fmt.Fprintf(socket, "<auth xmlns='%s' mechanism='PLAIN'>%s</auth>", nsSASL, enc)
+
+	// Next message should be either success or failure.
+	name, val, err := next(decoder)
+	if err != nil {
+		return err
+	}
+
+	switch v := val.(type) {
+	case *saslSuccess:
+	case *saslFailure:
+		// v.Any is type of sub-element in failure, which gives a description of what failed.
+		return errors.New("auth failure: " + v.Any.Local)
+	default:
+		return errors.New("expected success or failure, got " + name.Local + " in " + name.Space)
+	}
+	return err
+}
+
+// XMPP Packet Parsing
+type saslMechanisms struct {
+	XMLName   xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl mechanisms"`
+	Mechanism []string `xml:"mechanism"`
+}
+
+type saslSuccess struct {
+	XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl success"`
+}
+
+type saslFailure struct {
+	XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl failure"`
+	Any     xml.Name // error reason is a subelement
+}
+
+type auth struct {
+	XMLName   xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl auth"`
+	Mechanism string   `xml:"mecanism,attr"`
+	Value     string   `xml:",innerxml"`
+}
+
+type bindBind struct {
+	XMLName  xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-bind bind"`
+	Resource string   `xml:"resource,omitempty"`
+	Jid      string   `xml:"jid,omitempty"`
+}
+
+func (*bindBind) IsIQPayload() {
+}
+
+// Session is obsolete in RFC 6121.
+// Added for compliance with RFC 3121.
+// Remove when ejabberd purely conforms to RFC 6121.
+type sessionSession struct {
+	XMLName  xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-session session"`
+	optional xml.Name // If it does exist, it mean we are not required to open session
+}