From 2f6b1a11209260f4ee7b9469e39d16e78fb23a0f Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 12:09:50 +0200
Subject: Add dummy handler for stream features elements

This is the first step to handle stream features correctly with the new
routing infrastructure.
---
 xmpp/router.go      | 2 +-
 xmpp/stream_pair.go | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/xmpp/router.go b/xmpp/router.go
index 839f870..879579d 100644
--- a/xmpp/router.go
+++ b/xmpp/router.go
@@ -22,7 +22,7 @@ type routingTable []struct {
 // variable would have the problem that it could be altered during execution.
 func getRoutingTable() routingTable {
 	return routingTable{
-		// TODO fill with entries
+		{xml.Name{`http://etherx.jabber.org/streams`, `features`}, streamFeaturesHandler},
 	}
 }
 
diff --git a/xmpp/stream_pair.go b/xmpp/stream_pair.go
index c9108d1..3e42cd1 100644
--- a/xmpp/stream_pair.go
+++ b/xmpp/stream_pair.go
@@ -90,3 +90,7 @@ func closeStream(s *session) {
 		log.Println("Could not encode stream end!")
 	}
 }
+
+func streamFeaturesHandler(e []xml.Token) {
+	log.Println("Received stream features")
+}
-- 
cgit v1.2.3-70-g09d2


From d6fa15b7b66d679b7a6291aa6c85780a09cb1755 Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 12:28:48 +0200
Subject: Add detection for SASL mechanism

This is needed to respond with a SASL auth attempt.
---
 xmpp/stream_pair.go | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/xmpp/stream_pair.go b/xmpp/stream_pair.go
index 3e42cd1..b353947 100644
--- a/xmpp/stream_pair.go
+++ b/xmpp/stream_pair.go
@@ -91,6 +91,31 @@ func closeStream(s *session) {
 	}
 }
 
+func getCharData(t xml.Token) string {
+	switch c := t.(type) {
+	case xml.CharData:
+		return string(c)
+	default:
+		return ""
+	}
+}
+
 func streamFeaturesHandler(e []xml.Token) {
-	log.Println("Received stream features")
+	mechanism := xml.Name{`urn:ietf:params:xml:ns:xmpp-sasl`, `mechanism`}
+
+	for i, t := range e {
+		switch s := t.(type) {
+		case xml.StartElement:
+			if s.Name == mechanism {
+				if i+1 < len(e) {
+					if getCharData(e[i+1]) == `PLAIN` {
+						log.Println("Got offer for SASL PLAIN")
+						return
+					}
+				}
+			}
+		}
+	}
+
+	log.Println("No compatible SASL mechanism offered!")
 }
-- 
cgit v1.2.3-70-g09d2


From 98740fdc1c777778054dc3e444b9f4542fe04abe Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 12:44:58 +0200
Subject: Move SASL mechanism detection to xmpp/sasl.go

---
 xmpp/sasl.go        | 30 ++++++++++++++++++++++++++++++
 xmpp/stream_pair.go | 30 +++++-------------------------
 2 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/xmpp/sasl.go b/xmpp/sasl.go
index 8687782..e06bcd5 100644
--- a/xmpp/sasl.go
+++ b/xmpp/sasl.go
@@ -34,3 +34,33 @@ func (s *session) sasl() {
 		}
 	}
 }
+
+// hasSaslPlain scans the given stream features XML element for the SASL PLAIN
+// mechanism which is supported by xengineering.eu/limox/xmpp. It returns true
+// if the stream has support for this mechanism and false otherwise.
+func hasSaslPlain(e []xml.Token) bool {
+	mechanism := xml.Name{`urn:ietf:params:xml:ns:xmpp-sasl`, `mechanism`}
+
+	for i, t := range e {
+		switch s := t.(type) {
+		case xml.StartElement:
+			if s.Name == mechanism {
+				if i+1 < len(e) {
+					subtype := func() string {
+						switch c := e[i+1].(type) {
+						case xml.CharData:
+							return string(c)
+						default:
+							return ""
+						}
+					}()
+					if subtype == `PLAIN` {
+						return true
+					}
+				}
+			}
+		}
+	}
+
+	return false
+}
diff --git a/xmpp/stream_pair.go b/xmpp/stream_pair.go
index b353947..8f70318 100644
--- a/xmpp/stream_pair.go
+++ b/xmpp/stream_pair.go
@@ -91,31 +91,11 @@ func closeStream(s *session) {
 	}
 }
 
-func getCharData(t xml.Token) string {
-	switch c := t.(type) {
-	case xml.CharData:
-		return string(c)
-	default:
-		return ""
-	}
-}
-
 func streamFeaturesHandler(e []xml.Token) {
-	mechanism := xml.Name{`urn:ietf:params:xml:ns:xmpp-sasl`, `mechanism`}
-
-	for i, t := range e {
-		switch s := t.(type) {
-		case xml.StartElement:
-			if s.Name == mechanism {
-				if i+1 < len(e) {
-					if getCharData(e[i+1]) == `PLAIN` {
-						log.Println("Got offer for SASL PLAIN")
-						return
-					}
-				}
-			}
-		}
+	sasl := hasSaslPlain(e)
+	if sasl {
+		log.Println("Stream is compatible with SASL PLAIN mechanism")
+	} else {
+		log.Println("Stream is not compatible with SASL PLAIN mechanism!")
 	}
-
-	log.Println("No compatible SASL mechanism offered!")
 }
-- 
cgit v1.2.3-70-g09d2


From 372575cd38a939d1c8f412c8cea653c86bc725df Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:02:39 +0200
Subject: Fix debug message

---
 xmpp/sasl.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xmpp/sasl.go b/xmpp/sasl.go
index e06bcd5..e460f5e 100644
--- a/xmpp/sasl.go
+++ b/xmpp/sasl.go
@@ -29,7 +29,7 @@ func (s *session) sasl() {
 	for _, t := range tokens {
 		err := s.ed.encodeToken(t)
 		if err != nil {
-			log.Println("Could not encode stream end!")
+			log.Println("Could not encode SASL PLAIN element!")
 			return
 		}
 	}
-- 
cgit v1.2.3-70-g09d2


From 8b608265772ba5df13d24071117c694bdfd1212a Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:07:12 +0200
Subject: Add session pointer to routing infrastructure

It is nearly useless to route a XML element to an appropriate handler
function if the latter has no idea how to send responses to the server
or the GUI. Passing a pointer to the session solves this issue.
---
 xmpp/router.go      | 6 +++---
 xmpp/router_test.go | 7 ++++---
 xmpp/stream_pair.go | 4 ++--
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/xmpp/router.go b/xmpp/router.go
index 879579d..bd619b4 100644
--- a/xmpp/router.go
+++ b/xmpp/router.go
@@ -12,7 +12,7 @@ import (
 // entry of the routingTable.
 type routingTable []struct {
 	name    xml.Name
-	handler func([]xml.Token)
+	handler func(*session, []xml.Token)
 }
 
 // getRoutingTable returns the routing table used in
@@ -29,7 +29,7 @@ func getRoutingTable() routingTable {
 // route determines the correct handler function for the given XML element by a
 // given routingTable. In addition it executes the determined handler function.
 // If no handler function is found an error message is send via the log module.
-func route(e []xml.Token, t routingTable) {
+func route(s *session, e []xml.Token, t routingTable) {
 	var name xml.Name
 
 	// TODO a stronger definition of an XML element (as here
@@ -50,7 +50,7 @@ func route(e []xml.Token, t routingTable) {
 
 	for _, r := range t {
 		if name == r.name {
-			r.handler(e)
+			r.handler(s, e)
 			return
 		}
 	}
diff --git a/xmpp/router_test.go b/xmpp/router_test.go
index ea13712..41484c5 100644
--- a/xmpp/router_test.go
+++ b/xmpp/router_test.go
@@ -23,9 +23,10 @@ type routerTest struct {
 // validated.
 func TestRouter(t *testing.T) {
 	var testpoint int
+	var s session
 
-	factory := func(tp *int, i int) func([]xml.Token) {
-		return func([]xml.Token) {
+	factory := func(tp *int, i int) func(*session, []xml.Token) {
+		return func(*session, []xml.Token) {
 			*tp = i
 		}
 	}
@@ -60,7 +61,7 @@ func TestRouter(t *testing.T) {
 			tokens = append(tokens, xml.CopyToken(token))
 		}
 
-		route(tokens, testRouting)
+		route(&s, tokens, testRouting)
 
 		if testpoint != v.value {
 			t.Fatalf("XML element was not routed correctly!\n")
diff --git a/xmpp/stream_pair.go b/xmpp/stream_pair.go
index 8f70318..8ec06a6 100644
--- a/xmpp/stream_pair.go
+++ b/xmpp/stream_pair.go
@@ -28,7 +28,7 @@ func runStreamPair(s *session) {
 			}
 			if buf.isComplete() {
 				element := buf.reset()
-				route(element, getRoutingTable())
+				route(s, element, getRoutingTable())
 			}
 		}
 	}
@@ -91,7 +91,7 @@ func closeStream(s *session) {
 	}
 }
 
-func streamFeaturesHandler(e []xml.Token) {
+func streamFeaturesHandler(s *session, e []xml.Token) {
 	sasl := hasSaslPlain(e)
 	if sasl {
 		log.Println("Stream is compatible with SASL PLAIN mechanism")
-- 
cgit v1.2.3-70-g09d2


From c87ed02bb55a652b8908c336c3afd5635afdc1a7 Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:09:37 +0200
Subject: Send SASL request based on new routing

---
 xmpp/stream_pair.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xmpp/stream_pair.go b/xmpp/stream_pair.go
index 8ec06a6..5674d7b 100644
--- a/xmpp/stream_pair.go
+++ b/xmpp/stream_pair.go
@@ -94,7 +94,7 @@ func closeStream(s *session) {
 func streamFeaturesHandler(s *session, e []xml.Token) {
 	sasl := hasSaslPlain(e)
 	if sasl {
-		log.Println("Stream is compatible with SASL PLAIN mechanism")
+		s.sasl()
 	} else {
 		log.Println("Stream is not compatible with SASL PLAIN mechanism!")
 	}
-- 
cgit v1.2.3-70-g09d2


From f3aa8bec6e7d91b84a73688191751f9723c008a8 Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:21:34 +0200
Subject: Add SASL success handler

---
 xmpp/router.go | 1 +
 xmpp/sasl.go   | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/xmpp/router.go b/xmpp/router.go
index bd619b4..84256bb 100644
--- a/xmpp/router.go
+++ b/xmpp/router.go
@@ -23,6 +23,7 @@ type routingTable []struct {
 func getRoutingTable() routingTable {
 	return routingTable{
 		{xml.Name{`http://etherx.jabber.org/streams`, `features`}, streamFeaturesHandler},
+		{xml.Name{`urn:ietf:params:xml:ns:xmpp-sasl`, `success`}, saslSuccessHandler},
 	}
 }
 
diff --git a/xmpp/sasl.go b/xmpp/sasl.go
index e460f5e..62c312f 100644
--- a/xmpp/sasl.go
+++ b/xmpp/sasl.go
@@ -64,3 +64,6 @@ func hasSaslPlain(e []xml.Token) bool {
 
 	return false
 }
+
+func saslSuccessHandler(s *session, e []xml.Token) {
+}
-- 
cgit v1.2.3-70-g09d2


From 04f24e0dade8caf029cb78d3281b3587a8362cbe Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:22:15 +0200
Subject: Rework and apply stream nesting on SASL success

If SASL authentication is successful a new stream has to be opened by
the client. This is implemented with this commit.
---
 xmpp/sasl.go        |  1 +
 xmpp/session.go     |  1 -
 xmpp/stream_pair.go | 15 ++++++++-------
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/xmpp/sasl.go b/xmpp/sasl.go
index 62c312f..23e8f3f 100644
--- a/xmpp/sasl.go
+++ b/xmpp/sasl.go
@@ -66,4 +66,5 @@ func hasSaslPlain(e []xml.Token) bool {
 }
 
 func saslSuccessHandler(s *session, e []xml.Token) {
+	runStreamPair(s)
 }
diff --git a/xmpp/session.go b/xmpp/session.go
index f14cd34..bfa2582 100644
--- a/xmpp/session.go
+++ b/xmpp/session.go
@@ -19,7 +19,6 @@ type session struct {
 	transport *tls.Conn
 	ed        encoderDecoder
 	rx        chan xml.Token
-	streamEnd xml.EndElement
 }
 
 func StartSession(out chan<- any, jid string, pwd string) (in chan<- any) {
diff --git a/xmpp/stream_pair.go b/xmpp/stream_pair.go
index 5674d7b..f1de345 100644
--- a/xmpp/stream_pair.go
+++ b/xmpp/stream_pair.go
@@ -6,8 +6,8 @@ import (
 )
 
 func runStreamPair(s *session) {
-	openStream(s)
-	defer closeStream(s)
+	end := openStream(s)
+	defer closeStream(s, end)
 
 	buf := newElementBuffer()
 
@@ -34,7 +34,7 @@ func runStreamPair(s *session) {
 	}
 }
 
-func openStream(s *session) {
+func openStream(s *session) xml.EndElement {
 	start := xml.StartElement{
 		xml.Name{"jabber:client", "stream:stream"},
 		[]xml.Attr{
@@ -45,8 +45,7 @@ func openStream(s *session) {
 			xml.Attr{xml.Name{"", "xmlns:stream"}, "http://etherx.jabber.org/streams"},
 		},
 	}
-
-	s.streamEnd = start.End()
+	end := start.End()
 
 	err := s.ed.encodeToken(start)
 	if err != nil {
@@ -54,6 +53,8 @@ func openStream(s *session) {
 	}
 
 	syncStreams(s)
+
+	return end
 }
 
 // syncStreams drops XML tokens from the receiving stream until an
@@ -84,8 +85,8 @@ func syncStreams(s *session) {
 	}
 }
 
-func closeStream(s *session) {
-	err := s.ed.encodeToken(s.streamEnd)
+func closeStream(s *session, end xml.EndElement) {
+	err := s.ed.encodeToken(end)
 	if err != nil {
 		log.Println("Could not encode stream end!")
 	}
-- 
cgit v1.2.3-70-g09d2


From 6fd36e07a5d645295f34fcbab36cce5e08a9d84c Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:28:06 +0200
Subject: Make streamFeaturesHandler() more generic

The new structure allows to check for different stream features and act
according to them or - if nothing matches - do nothing apart from an
error message to the log.
---
 xmpp/stream_pair.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/xmpp/stream_pair.go b/xmpp/stream_pair.go
index f1de345..693972e 100644
--- a/xmpp/stream_pair.go
+++ b/xmpp/stream_pair.go
@@ -93,10 +93,10 @@ func closeStream(s *session, end xml.EndElement) {
 }
 
 func streamFeaturesHandler(s *session, e []xml.Token) {
-	sasl := hasSaslPlain(e)
-	if sasl {
+	if hasSaslPlain(e) {
 		s.sasl()
-	} else {
-		log.Println("Stream is not compatible with SASL PLAIN mechanism!")
+		return
 	}
+
+	log.Println("Stream has no implemented features!")
 }
-- 
cgit v1.2.3-70-g09d2


From d7a537267e8bf5631e29ed97218e213da88f3490 Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:33:14 +0200
Subject: Implement basic handler for failed SASL auth

Writing to the log is still better than doing nothing ...
---
 xmpp/router.go | 1 +
 xmpp/sasl.go   | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/xmpp/router.go b/xmpp/router.go
index 84256bb..9d69033 100644
--- a/xmpp/router.go
+++ b/xmpp/router.go
@@ -24,6 +24,7 @@ func getRoutingTable() routingTable {
 	return routingTable{
 		{xml.Name{`http://etherx.jabber.org/streams`, `features`}, streamFeaturesHandler},
 		{xml.Name{`urn:ietf:params:xml:ns:xmpp-sasl`, `success`}, saslSuccessHandler},
+		{xml.Name{`urn:ietf:params:xml:ns:xmpp-sasl`, `failure`}, saslFailureHandler},
 	}
 }
 
diff --git a/xmpp/sasl.go b/xmpp/sasl.go
index 23e8f3f..512fd58 100644
--- a/xmpp/sasl.go
+++ b/xmpp/sasl.go
@@ -68,3 +68,7 @@ func hasSaslPlain(e []xml.Token) bool {
 func saslSuccessHandler(s *session, e []xml.Token) {
 	runStreamPair(s)
 }
+
+func saslFailureHandler(s *session, e []xml.Token) {
+	log.Println("SASL autentication failed!")
+}
-- 
cgit v1.2.3-70-g09d2


From 3dc04660a87e1b9fabeea0e55a8511d80d34a694 Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Fri, 30 Jun 2023 13:57:52 +0200
Subject: Apply go fmt

---
 xmpp/element_buffer_test.go | 4 ++--
 xmpp/router_test.go         | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/xmpp/element_buffer_test.go b/xmpp/element_buffer_test.go
index 113a2c4..af3d5c2 100644
--- a/xmpp/element_buffer_test.go
+++ b/xmpp/element_buffer_test.go
@@ -11,8 +11,8 @@ import (
 // which has to be exactly one XML element and an array of indentation levels
 // which have to be checked after each token which is parsed.
 type bufTest struct {
-	xml     string
-	levels  []int
+	xml    string
+	levels []int
 }
 
 func TestElementBuffer(t *testing.T) {
diff --git a/xmpp/router_test.go b/xmpp/router_test.go
index 41484c5..b490778 100644
--- a/xmpp/router_test.go
+++ b/xmpp/router_test.go
@@ -2,8 +2,8 @@ package xmpp
 
 import (
 	"encoding/xml"
-	"testing"
 	"strings"
+	"testing"
 )
 
 // routerTest contains a single test case for the xmpp.router. The XML element
@@ -11,8 +11,8 @@ import (
 // test variable inside the corresponding unit test. See TestRouter for
 // details.
 type routerTest struct {
-	xml     string
-	value   int
+	xml   string
+	value int
 }
 
 // TestRouter tests the xmpp/router.go file. The central functionality is the
-- 
cgit v1.2.3-70-g09d2