gsm0808: Be able to parse a ciphering mode complete with layer3 contents

BSSMAP.st

@@ -797,3 +797,31 @@ GSM0808IE subclass: GSM0808Classmark3IE [
         aMsg putByteArray: cm.
     ]
 ]
+
+GSM0808IE subclass: GSM0808Layer3MessageContents [
+    | layer3Message |
+    <category: 'OsmoGSM'>
+
+    GSM0808Layer3MessageContents class >> elementId [^32]
+    GSM0808Layer3MessageContents class >> initWith: aByteArray [
+        ^self new
+            layer3Message: aByteArray;
+            yourself
+    ]
+
+    GSM0808Layer3MessageContents class >> parseFrom: aStream [
+        | size |
+        size := aStream next.
+        ^self initWith: (aStream next: size)
+    ]
+
+    layer3Message: aByteArray [
+        layer3Message := aByteArray
+    ]
+
+    writeOnDirect: aMsg [
+        aMsg
+            putByte: layer3Message size;
+            putByteArray: layer3Message.
+    ]
+]

Tests.st

@@ -595,6 +595,12 @@ TestCase subclass: TestMessages [
         msg := MSGParser parse: inp.
         self assert: msg toMessage asByteArray = inp.
 
+	"Ciphering mode complete..."
+        inp := #[16r06 16r01 16r01 16r5B 16r00 16r01 16r14 16r00 16r12 16r55 16r20 16r0D 16r06 16r32 16r17 16r09 16r33 16r15 16r49 16r00 16r93 16r89 16r31 16r62 16rF4 16r2C 16r02].
+        msg := MSGParser parse: inp.
+        self assert: msg toMessage asByteArray = inp.
+
+
         "Assignment Command"
         inp := #(6 0 0 72 0 1 11 0 9 1 11 3 1 10 17 1 0 20 ) asByteArray.
         msg := MSGParser parse: inp.