sccp: Implement connection refused parsing and handling

The code can not parse the optional elements yet.

Tests.st

@@ -105,6 +105,20 @@ TestCase subclass: SCCPTests [
         self assert: cc toMessage asByteArray = target.
     ]
 
+    testCREF [
+        | target cref |
+
+        target := #[16r03 16r1A 16r00 16r03 16r00 16r01 16r00].
+
+        cref := SCCPConnectionRefused
+                    initWithDst: 16r03001A cause: 16r00.
+        self assert: cref toMessage asByteArray = target.
+
+        cref := SCCPMessage decode: target.
+        self assert: (cref isKindOf: SCCPConnectionRefused).
+        self assert: cref dst = 16r03001A.
+    ]
+
     testRlsd [
         | target rlsd |
 

sccp/SCCP.st

@@ -364,6 +364,62 @@ SCCPMessage subclass: SCCPConnectionConfirm [
     ]
 ]
 
+SCCPMessage subclass: SCCPConnectionRefused [
+    | dst cause |
+
+    <category: 'OsmoNetwork-SCCP'>
+    <comment: 'I hold the data of a connection refused.'>
+
+    SCCPConnectionRefused class >> msgType [
+        <category: 'factory'>
+        ^SCCPHelper msgCref
+    ]
+
+    SCCPConnectionRefused class >> initWithDst: aDst cause: aCause [
+        <category: 'creation'>
+        ^self new
+            dst: aDst;
+            cause: aCause;
+            yourself
+    ]
+
+    SCCPConnectionRefused class >> parseFrom: aMsg [
+        | dst cause |
+        <category: 'parsing'>
+
+        dst := SCCPAddrReference fromByteArray: (aMsg copyFrom: 2 to: 4).
+        cause := aMsg at: 5.
+        ^self initWithDst: dst cause: cause.
+    ]
+
+    dst: aDst [
+        dst := aDst
+    ]
+
+    dst [
+        ^dst
+    ]
+
+    cause: aCause [
+        cause := aCause
+    ]
+
+    cause [
+        ^cause
+    ]
+
+    writeOn: aMsg [
+        <category: 'encoding'>
+
+        aMsg putByte: self class msgType.
+        SCCPAddrReference store: dst on: aMsg.
+        aMsg putByte: cause.
+
+        "End of optional?"
+        aMsg putByte: 1; putByte: 0.
+    ]
+]
+
 SCCPMessage subclass: SCCPConnectionData [
     | dst data |