From 53661cda2f8622fb9d870116980586ce681328cb Mon Sep 17 00:00:00 2001
From: Valentin D'Emmanuele <valentin@devling.xyz>
Date: Mon, 25 Mar 2024 18:23:07 +0100
Subject: [PATCH] Fix Marshaling of Dialogue

---
 dialogue-pdu.go |  3 ++-
 dialogue.go     | 46 ++++++++++++++++++++++++++--------------------
 tcap.go         |  1 +
 3 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/dialogue-pdu.go b/dialogue-pdu.go
index a080be2..446d675 100644
--- a/dialogue-pdu.go
+++ b/dialogue-pdu.go
@@ -702,7 +702,7 @@ func (d *DialoguePDU) ContextVersion() string {
 
 // String returns DialoguePDU in human readable string.
 func (d *DialoguePDU) String() string {
-	return fmt.Sprintf("{Type: %#x, Length: %d, ProtocolVersion: %v, ApplicationContextName: %v, Result: %v, ResultSourceDiagnostic: %v, AbortSource: %v}",
+	return fmt.Sprintf("{Type: %#x, Length: %d, ProtocolVersion: %v, ApplicationContextName: %v, Result: %v, ResultSourceDiagnostic: %v, AbortSource: %v, UserInformation: %v}",
 		d.Type,
 		d.Length,
 		d.ProtocolVersion,
@@ -710,5 +710,6 @@ func (d *DialoguePDU) String() string {
 		d.Result,
 		d.ResultSourceDiagnostic,
 		d.AbortSource,
+		d.UserInformation,
 	)
 }
diff --git a/dialogue.go b/dialogue.go
index 9d99484..11c0221 100644
--- a/dialogue.go
+++ b/dialogue.go
@@ -24,7 +24,7 @@ type Dialogue struct {
 	ExternalTag      Tag
 	ExternalLength   uint8
 	ObjectIdentifier *IE
-	SingleAsn1Type   *IE
+	singleAsn1Type   *IE
 	DialoguePDU      *DialoguePDU
 	Payload          []byte
 }
@@ -39,7 +39,7 @@ func NewDialogue(oid, ver uint8, pdu *DialoguePDU, payload []byte) *Dialogue {
 			Length: 7,
 			Value:  []byte{0, 17, 134, 5, 1, oid, ver},
 		},
-		SingleAsn1Type: &IE{
+		singleAsn1Type: &IE{
 			Tag:    NewContextSpecificConstructorTag(0),
 			Length: uint8(pdu.MarshalLen()),
 		},
@@ -78,14 +78,16 @@ func (d *Dialogue) MarshalTo(b []byte) error {
 		offset += field.MarshalLen()
 	}
 
-	if field := d.SingleAsn1Type; field != nil {
-		if err := field.MarshalTo(b[offset : offset+field.MarshalLen()]); err != nil {
-			return err
+	if field := d.singleAsn1Type; field != nil {
+		if field := d.DialoguePDU; field != nil {
+			d.singleAsn1Type.Value = make([]byte, d.DialoguePDU.MarshalLen())
+
+			if err := d.DialoguePDU.MarshalTo(d.singleAsn1Type.Value); err != nil {
+				return err
+			}
 		}
-		offset += field.MarshalLen()
-	}
 
-	if field := d.DialoguePDU; field != nil {
+		d.singleAsn1Type.SetLength()
 		if err := field.MarshalTo(b[offset : offset+field.MarshalLen()]); err != nil {
 			return err
 		}
@@ -93,6 +95,7 @@ func (d *Dialogue) MarshalTo(b []byte) error {
 	}
 
 	copy(b[offset:], d.Payload)
+
 	return nil
 }
 
@@ -125,13 +128,13 @@ func (d *Dialogue) UnmarshalBinary(b []byte) error {
 	}
 	offset += d.ObjectIdentifier.MarshalLen()
 
-	d.SingleAsn1Type, err = ParseIE(b[offset:])
+	d.singleAsn1Type, err = ParseIE(b[offset:])
 	if err != nil {
 		return err
 	}
-	offset += d.SingleAsn1Type.MarshalLen()
+	offset += d.singleAsn1Type.MarshalLen()
 
-	d.DialoguePDU, err = ParseDialoguePDU(d.SingleAsn1Type.Value)
+	d.DialoguePDU, err = ParseDialoguePDU(d.singleAsn1Type.Value)
 	if err != nil {
 		return err
 	}
@@ -155,7 +158,7 @@ func (d *Dialogue) SetValsFrom(berParsed *IE) error {
 				case 0x06:
 					d.ObjectIdentifier = iex
 				case 0xa0:
-					d.SingleAsn1Type = iex
+					d.singleAsn1Type = iex
 					dpdu = iex.IE[0]
 				}
 			}
@@ -190,32 +193,35 @@ func (d *Dialogue) MarshalLen() int {
 	if field := d.ObjectIdentifier; field != nil {
 		l += field.MarshalLen()
 	}
-	if field := d.SingleAsn1Type; field != nil {
-		l += field.MarshalLen()
-	}
 	if field := d.DialoguePDU; field != nil {
-		l += field.MarshalLen()
+		l += field.MarshalLen() + 2 // 2 = singleAsn1Type IE Header
 	}
-	l += len(d.Payload)
 
-	return l
+	return l + len(d.Payload)
 }
 
 // SetLength sets the length in Length field.
 func (d *Dialogue) SetLength() {
+	if field := d.ObjectIdentifier; field != nil {
+		d.ObjectIdentifier.SetLength()
+	}
+	if field := d.DialoguePDU; field != nil {
+		d.DialoguePDU.SetLength()
+	}
+
 	d.Length = uint8(d.MarshalLen() - 2)
 	d.ExternalLength = uint8(d.MarshalLen() - 4)
 }
 
 // String returns the SCCP common header values in human readable format.
 func (d *Dialogue) String() string {
-	return fmt.Sprintf("{Tag: %#x, Length: %d, ExternalTag: %x, ExternalLength: %d, ObjectIdentifier: %v, SingleAsn1Type: %v, DialoguePDU: %v, Payload: %x}",
+	return fmt.Sprintf("{Tag: %#x, Length: %d, ExternalTag: %x, ExternalLength: %d, ObjectIdentifier: %v, singleAsn1Type: %v, DialoguePDU: %v, Payload: %x}",
 		d.Tag,
 		d.Length,
 		d.ExternalTag,
 		d.ExternalLength,
 		d.ObjectIdentifier,
-		d.SingleAsn1Type,
+		d.singleAsn1Type,
 		d.DialoguePDU,
 		d.Payload,
 	)
diff --git a/tcap.go b/tcap.go
index b11b3d3..371d3d3 100644
--- a/tcap.go
+++ b/tcap.go
@@ -114,6 +114,7 @@ func Parse(b []byte) (*TCAP, error) {
 	if err := t.UnmarshalBinary(b); err != nil {
 		return nil, err
 	}
+
 	return t, nil
 }