misc: Move the sources into a subdirectory

I am still searching for a better way to group these files for
their specific main functionality.

10 files changed, 1853 insertions, 0 deletions

diff --git a/src/BSCConfig.st b/src/BSCConfig.st
new file mode 100644
index 0000000..6861c0f
--- /dev/null
+++ b/src/BSCConfig.st
@@ -0,0 +1,102 @@
+"
+ (C) 2010 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader fileInPackage: #Sockets.
+
+Object subclass: BSCConfigItem [
+    | peer token name lac connected |
+    <category: 'MSC-BSC'>
+    <comment: 'I hold the configuration for one BJSC Item. It consists of the
+peer address, the lac, if it is connected'>
+
+    BSCConfigItem class >> initWith: aPeer name: aName [
+        ^ self new
+            peer: aPeer; name: aName; lac: -1; connected: false; yourself
+    ]
+
+    BSCConfigItem class >> resolveAddress: aPeer [
+        ^ aPeer isString
+            ifTrue:  [Sockets.SocketAddress byName: aPeer]
+            ifFalse: [aPeer].
+    ]
+
+    peer [ <category: 'accessing'> ^ peer ]
+    peer: aPeer [
+        <category: 'private'>
+
+        peer := self class resolveAddress: aPeer.
+    ]
+
+    name [ <category: 'accessing'> ^ name ]
+    name: aName [
+        <category: 'private'>
+        name := aName.
+    ]
+
+    lac [ <category: 'accessing'> ^ lac ]
+    lac: aLac [
+        <category: 'private'>
+        lac := aLac.
+    ]
+
+    connected [ <category: 'accessing'> ^ connected ]
+    connected: aState [
+        <category: 'private'>
+        connected := aState.
+    ]
+]
+
+Object subclass: BSCConfig [
+    | bscList |
+    <category: 'MSC-BSC'>
+    <comment: 'I know the BSCs that can connect to me'>
+
+    removeBSC: aPeer [
+        | peer |
+        peer := BSCConfigItem resolveAddress: aPeer.
+        self bscList removeAllSuchThat: [:element | element peer = peer].
+    ]
+
+    removeBSCByLac: aLac [
+        self bscList removeAllSuchThat: [:element | element lac = aLac].
+    ]
+
+    addBSC: ip withName: aName andLac: aLac [
+        | addr bsc |
+        <category: 'management'>
+        "Make sure that no one with the same IP or LAC registers"
+
+        addr := Sockets.SocketAddress byName: ip.
+        bsc := BSCConfigItem initWith: addr name: aName.
+        bsc lac: aLac.
+
+        (self bscList anySatisfy: [:each | each peer = addr ])
+            ifTrue: [
+                self error: 'The address needs to be unique'.
+        ].
+
+        (self bscList anySatisfy: [:each | each lac = aLac])
+            ifTrue: [
+                self error: 'The lac needs to be unique'.
+        ].
+
+        self bscList add: bsc.
+    ]
+
+    bscList [ ^ bscList ifNil: [bscList := OrderedCollection new]]
+]
diff --git a/src/BSCIPAConnection.st b/src/BSCIPAConnection.st
new file mode 100644
index 0000000..d72e927
--- /dev/null
+++ b/src/BSCIPAConnection.st
@@ -0,0 +1,183 @@
+"
+ (C) 2010-2011 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader
+    fileInPackage: 'OsmoMGCP';
+    fileInPackage: 'OsmoNetwork'.
+
+OsmoGSM.SCCPHandler subclass: BSCSCCPHandler [
+    | bsc msc |
+    <comment: 'I handle SCCP for the MSC/BSC connection'>
+
+    BSCSCCPHandler class >> initWith: aBSC msc: aMSC [
+        ^ self new
+            instVarNamed: #bsc put: aBSC;
+            instVarNamed: #msc put: aMSC;
+            yourself
+    ]
+
+    connectionSpecies [
+        ^ GSMProcessor
+    ]
+
+    bsc [
+        <category: 'accessing'>
+        ^ bsc
+    ]
+
+    msc [
+        <category: 'accessing'>
+        ^ msc
+    ]
+
+    handleMsg: aMsg [
+        ^ super handleMsg: aMsg.
+    ]
+
+    newConnection: aConnection [
+        self logNotice: 'New incoming SCCP connection %1 on the BSC %2'
+             % {aConnection srcRef. bsc lac} area: #bsc.
+        ^ super newConnection: aConnection.
+    ]
+]
+
+Object subclass: BSCConnection [
+    | config msc trunk |
+
+    BSCConnection class >> createOn: aConfig msc: aMsc [
+        <category: 'creation'>
+        ^ self new
+            instVarNamed: #config put: aConfig;
+            instVarNamed: #msc put: aMsc;
+            initialize;
+            yourself
+    ]
+
+    initialize [
+        <category: 'creation'>
+        "I try to initialize the trunk. Right now I force the usage
+        of UDP to the given port and do not support the nat traversal. I
+        also hardcode the kind of audio."
+        trunk := Osmo.MGCPDSTrunk createWithDest: config peer printString trunkNr: 1.
+        (trunk endpointAt: 1) tryBlock.
+    ]
+
+    config [
+        <category: 'accessing'>
+        ^ config
+    ]
+
+    msc [
+        <category: 'accessing'>
+        ^ msc
+    ]
+
+    trunk [
+        <category: 'accessing'>
+        ^ trunk
+    ]
+]
+
+BSCConnection subclass: BSCIPAConnection [
+    | socket demuxer writeQueue muxer dispatcher sccp tx terminated ipa |
+    <comment: 'I represent one Connection to a BSC and use the IPA
+     protocol to exchange messages. I will be executed from within
+     a thread and can do a blocking read from in here.'>
+
+    BSCIPAConnection class >> createOn: aSocket withConfig: aConfig msc: aMsc [
+        ^ (self createOn: aConfig msc: aMsc)
+            socket: aSocket;
+            yourself
+    ]
+
+    BSCIPAConnection class >> terminate: aProc [
+        "Make sure it is dead!"
+        aProc ifNil: [^true].
+
+        [aProc isTerminated] whileFalse: [aProc terminate].
+    ]
+
+    lac [ ^ config lac ]
+
+    socket: aSocket [
+        socket := aSocket.
+        writeQueue := SharedQueue new.
+
+        demuxer := Osmo.IPADemuxer initOn: socket.
+        muxer := Osmo.IPAMuxer initOn: writeQueue.
+
+        dispatcher := Osmo.IPADispatcher new.
+        dispatcher initialize.
+
+        ipa := Osmo.IPAProtoHandler new.
+        ipa registerOn: dispatcher.
+        ipa muxer: muxer.
+        ipa token: 'abc'.
+
+        sccp := BSCSCCPHandler initWith: self msc: msc.
+        sccp registerOn: dispatcher.
+        sccp connection: self.
+
+        "Drain the send queue in a new process"
+        tx := [
+            [[
+                | msg |
+                msg := writeQueue next.
+                socket nextPutAllFlush: msg.
+            ] repeat.
+            ] ensure: [
+                self logNotice: 'BSC TX queue lac: %1 finished' % {self lac} area: #bsc]
+        ] fork.
+
+    ]
+
+    send: aMsg with: aType [
+        terminated = true ifTrue: [^false].
+
+        muxer nextPut: aMsg with: aType.
+    ]
+
+    process [
+        "Drive the BSC process. This will send/queue messages"
+
+        socket logNotice: 'Processing for lac %1' % {self lac} area: #bsc.
+
+        self send: {Osmo.IPAConstants msgIdAck} asByteArray with: Osmo.IPAConstants protocolIPA.
+
+        [
+            self processOne.
+        ] repeat.
+
+
+        socket close.
+    ]
+
+    processOne [
+        | msg |
+        msg := demuxer next.
+        OsmoDispatcher dispatchBlock: [dispatcher dispatch: msg first with: msg second.]
+    ]
+
+    terminateAll [
+        "Bring down everything that happens for this BSC. This is a reset"
+        terminated := true.
+        self logNotice: 'BSC lac: %1 terminating.' % {self lac} area: #bsc.
+        self class terminate: tx.
+        OsmoDispatcher dispatchBlock: [sccp linkSetFailed].
+    ]
+]
diff --git a/src/BSCListener.st b/src/BSCListener.st
new file mode 100644
index 0000000..b0e94ff
--- /dev/null
+++ b/src/BSCListener.st
@@ -0,0 +1,79 @@
+"
+ (C) 2010 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader fileInPackage: 'Sockets'.
+
+Object subclass: BSCListener [
+    | ip port socket handler |
+
+    <comment: 'I listen for incoming BSC connections and will
+    authenticate them based on a definable criteria. Right now
+    this is based on IP address'>
+
+    BSCListener class >> initWith: bscIP port: bscPort handler: aHandler [
+        ^ self new
+            initSocket: bscIP port: bscPort;
+            handler: aHandler;
+            start;
+            yourself
+    ]
+
+    handler: aHandler [
+        handler := aHandler.
+    ]
+
+    initSocket: anIP port: aPort [
+        ip := anIP.
+        port := aPort.
+    ]
+
+    serve [
+	[true] whileTrue: [
+            [ | con |
+                socket waitForConnection.
+                con := socket accept.
+                con ifNil: [
+                    self logNotice: 'BSC-Socket: Connection failed. Will return.' area: #bsc.
+                    ^ false
+                ].
+
+                handler isNil
+                    ifTrue: [con close]
+                    ifFalse:[handler newConnection: con].
+            ] on: SystemExceptions.FileError do: [:each |
+                self logNotice: 'BSC-Socket: FileError on connection handling.' area: #bsc.
+                ^ false.
+            ].
+        ]
+    ]
+
+    start [
+        [
+            socket := Sockets.ServerSocket
+                port: port bindTo: (Sockets.SocketAddress byName: ip).
+        ] on: SystemExceptions.FileError do: [:e |
+            e logException: 'BSC-Socket: Failed to bind.' area: #bsc.
+        ]
+    ]
+
+    stop [
+        "The serve function will now get a FileError"
+        self logNotice: 'BSC-Socket: Asked to close the connection.' area: #bsc.
+        socket close.
+    ]
+]
diff --git a/src/GSMMOCall.st b/src/GSMMOCall.st
new file mode 100644
index 0000000..0db182a
--- /dev/null
+++ b/src/GSMMOCall.st
@@ -0,0 +1,284 @@
+"
+ (C) 2011 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+OsmoGSM.GSM48MSG extend [
+    dispatchMoCall: aCon [
+        aCon moUnknown: self.
+    ]
+]
+
+OsmoGSM.GSM48CCConnectAck extend [
+    dispatchMoCall: aCon [
+        aCon moConnectAck: self.
+    ]
+]
+
+OsmoGSM.GSM48CCDisconnect extend [
+    dispatchMoCall: aCon [
+        aCon moDisconnect: self.
+    ]
+]
+
+OsmoGSM.GSM48CCRelease extend [
+    dispatchMoCall: aCon [
+        aCon moRelease: self.
+    ]
+]
+
+OsmoGSM.GSM48CCReleaseCompl extend [
+    dispatchMoCall: aCon [
+        aCon moReleaseCompl: self.
+    ]
+]
+
+OsmoGSM.GSM48CCStatus extend [
+    dispatchMoCall: aCon [
+        aCon moStatus: self.
+    ]
+]
+
+OsmoGSM.GSM48CCSetup extend [
+    openTransactionOn: aCon sapi: aSapi [
+        | tran |
+        tran := (GSMMOCall on: aSapi with: self ti)
+                    con: aCon;
+                    yourself.
+        aCon addTransaction: tran.
+        tran start: self.
+    ]
+]
+
+GSMTransaction subclass: GSMMOCall [
+    | state wait_for_ass remoteLeg |
+    <comment: 'I handle Mobile-Originated calls as of 5.2.1 of GSM 04.08. I should
+    represent the states found in Figure 5.1b/3GPP TS 04.08: Overview call controll
+    protocol/Network side. Right now the set of states is incomplete and is mixed
+    for MO and MT. It is not very clear if the text and the state machine fit together.'>
+
+    GSMMOCall class >> stateNull        [ <category: 'states'> ^ #null ]
+    GSMMOCall class >> stateProceeding  [ <category: 'states'> ^ #proceeding ]
+    GSMMOCall class >> stateConnectInd  [ <category: 'states'> ^ #connect_indication ]
+    GSMMOCall class >> stateActive      [ <category: 'states'> ^ #active ]
+    GSMMOCall class >> stateDisconnInd  [ <category: 'states'> ^ #disconn_ind ]
+    GSMMOCall class >> stateReleaseReq  [ <category: 'states'> ^ #release_req ]
+    GSMMOCall class >> stateReleaseCompl [ <category: 'states'> ^ #release_compl ]
+
+    initialize [
+        <category: 'creation'>
+        state := self class stateNull.
+    ]
+
+    nextPutSapi: aMsg [
+        <category: 'output'>
+        aMsg ti: (ti bitOr: 8).
+        aMsg seq: 0.
+        ^ super nextPutSapi: aMsg.
+    ]
+
+    netAlerting [
+        <category: 'external'>
+        "I am called by the other side of the call"
+
+        (state = self class stateProceeding) ifTrue: [
+            con sendMDCX: remoteLeg sdpAlert state: 'recvonly'.
+            self sendAlerting.
+        ].
+    ]
+
+    netConnect [
+        <category: 'external'>
+        "I am called by the other side of the call. I will need to get
+         the SDP file of this side to send a MGCP message down the stream."
+
+        (state = self class stateProceeding) ifTrue: [
+            state := self class stateConnectInd.
+            con sendMDCX: remoteLeg sdp state: 'sendrecv'.
+            self sendConnect.
+        ].
+    ]
+
+    netTerminate [
+        <category: 'external'>
+        "The other side of the call has terminated, let
+        us do the clean up."
+        remoteLeg isNil ifFalse: [
+            remoteLeg := nil.
+            state := self class stateDisconnInd.
+            self sendDisconnect: #(16rE1 16r90)
+        ].
+    ]
+
+    moConnectAck: aMsg [
+        <category: 'mo-message'>
+        (state = self class stateConnectInd) ifTrue: [
+            self logNotice: 'GSMMOCall(srcref:%1) call is connected.'
+                % {con srcRef} area: #bsc.
+            state := self class stateActive.
+        ].
+    ]
+
+    moDisconnect: aMsg [
+        <category: 'mo-message'>
+        state := self class stateDisconnInd.
+        self sendRelease: #(16rE1 16r90).
+
+        "Disconnect the remote"
+        remoteLeg isNil ifFalse: [
+            remoteLeg netTerminate.
+            remoteLeg := nil.
+        ].
+    ]
+
+    moRelease: aMsg [
+        <category: 'mo-message'>
+        state = self class stateDisconnInd ifFalse: [
+            self logError: 'GSMMOCall(srcref:%1) release in state %2'
+                % {con srcRef. self state} area: #bsc.
+        ].
+
+        self releaseComplete.
+    ]
+
+    moReleaseCompl: aMsg [
+        <category: 'mo-message'>
+        self cancel.
+        con removeTransaction: self.
+    ]
+
+    moUnknown: aMsg [
+        <category: 'mo-message'>
+        ^ self logUnknown: aMsg.
+    ]
+
+    moStatus: aMsg [
+        <category: 'mo-message'>
+        "We did something wrong, just give up and see how it can be fixed."
+        self logError: 'GSMOCall(srcref:%1) something wrong with call state.'
+                % {con srcRef} area: #bsc.
+        self cancel.
+        con removeTransaction: self.
+    ]
+
+    dispatch: aMsg [
+        aMsg dispatchMoCall: self.
+    ]
+
+    sendReleaseComplete: aCause [
+        | rlc |
+        <category: 'gsm-routines'>
+
+        rlc := OsmoGSM.GSM48CCReleaseCompl new.
+        rlc causeOrDefault data: aCause.
+        self nextPutSapi: rlc.
+    ]
+
+    sendRelease: aCause [
+        | rel |
+        <category: 'gsm-routines'>
+        rel := OsmoGSM.GSM48CCRelease new.
+        rel causeOrDefault data: aCause.
+        self nextPutSapi: rel.
+    ]
+
+    sendProceeding [
+        | msg |
+        <category: 'gsm-routines'>
+
+        msg := OsmoGSM.GSM48CCProceeding new.
+        self nextPutSapi: msg.
+    ]
+
+    sendAlerting [
+        | msg |
+        <category: 'gsm-routines'>
+
+        msg := OsmoGSM.GSM48CCAlerting new.
+        self nextPutSapi: msg.
+    ]
+
+    sendConnect [
+        | msg |
+        <category: 'gsm-routines'>
+        msg := OsmoGSM.GSM48CCConnect new.
+        self nextPutSapi: msg.
+    ]
+
+    sendDisconnect: aCause [
+        | msg |
+        <category: 'gsm-routines'>
+
+        msg := OsmoGSM.GSM48CCDisconnect new.
+        msg cause data: aCause.
+        self nextPutSapi: msg.
+    ]
+
+    releaseComplete [
+        <category: 'transaction'>
+
+        state := self class stateReleaseCompl.
+        self sendReleaseComplete: #(16rE1 16r83).
+        self cancel.
+        con removeTransaction: self.
+    ]
+
+    start: aCCMessage [
+        <category: 'transaction'>
+
+        "select route for this call, or release the call"
+        remoteLeg := con selectAudioRoute: aCCMessage calledOrDefault leg: self.
+        remoteLeg isNil ifTrue: [
+            self logError:
+                'GSMMOCall(srcref:%1) failed to select audio route.'
+                    % {con srcRef} area: #bsc.
+            self releaseComplete.
+            ^ self
+        ].
+
+        "Failed to allocate an endpoint"
+        con allocateEndpoint isNil ifTrue: [
+            self releaseComplete.
+            ^ self
+        ].
+
+        "We are waiting for an assignment"
+        wait_for_ass := true.
+        state := self class stateProceeding.
+        self sendProceeding.
+
+        con sendAssignment.
+    ]
+
+    cancel [
+        remoteLeg ifNotNil: [remoteLeg netTerminate].
+        ^ super cancel
+    ]
+
+    assignmentFailure [
+        "The assignment failed, let's see if it could be for us"
+        wait_for_ass ifTrue: [
+            remoteLeg := nil.
+            self releaseComplete.
+        ]
+    ]
+
+    assignmentSuccess [
+        wait_for_ass := false.
+        remoteLeg createCall: con sdpFile.
+    ]
+]
+
diff --git a/src/GSMProcessor.st b/src/GSMProcessor.st
new file mode 100644
index 0000000..9b7a0b8
--- /dev/null
+++ b/src/GSMProcessor.st
@@ -0,0 +1,640 @@
+"
+ (C) 2010-2011 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader fileInPackage: 'OsmoGSM'.
+
+OsmoGSM.BSSAPMessage extend [
+    dispatchTrans: aCon [
+        aCon bssapUnknownData: self
+    ]
+]
+
+OsmoGSM.BSSAPManagement extend [
+    dispatchTrans: aCon [
+        self dispatchMAP: aCon.
+    ]
+
+    dispatchMAP: aCon [
+        (Dictionary from: {
+            OsmoGSM.GSM0808Helper msgComplL3   -> #mapLayer3:.
+            OsmoGSM.GSM0808Helper msgClearReq  -> #mapClearReq:.
+            OsmoGSM.GSM0808Helper msgClearComp -> #mapClearCompl:.
+            OsmoGSM.GSM0808Helper msgCipherModeCmpl -> #mapCipherModeCompl:.
+            OsmoGSM.GSM0808Helper msgAssComplete -> #mapAssComplete:.
+            OsmoGSM.GSM0808Helper msgAssFailure -> #mapAssFailure:.
+            }) at: self data type ifPresent: [:sel |
+            ^ aCon perform: sel with: self.
+        ].
+
+        ^ aCon mapUnknown: self.
+    ]
+]
+
+OsmoGSM.BSSAPDTAP extend [
+    dispatchTrans: aCon [
+        aCon dispatchDTAP: self.
+    ]
+]
+
+OsmoGSM.GSM48MSG extend [
+    openTransactionOn: aCon sapi: aSapi [
+        self logError: 'Can not open transaction for %1' % {self class} area: #bsc.
+    ]
+]
+
+Object subclass: GSMTransaction [
+    | sapi ti con |
+    <comment: 'I am the base for everything that goes on in a
+GSM transaction on a given SAPI'>
+
+    GSMTransaction class >> on: sapi with: ti [
+        <category: 'creation'>
+        ^ self new
+            instVarNamed: #sapi put: sapi;
+            instVarNamed: #ti put: ti;
+            initialize;
+            yourself
+    ]
+
+    sapi [
+        <category: 'accessing'>
+        ^ sapi
+    ]
+
+    ti [
+        "TODO: This should somehow include the size of the allocation"
+        <category: 'accessing'>
+        ^ ti
+    ]
+
+    con: aCon [
+        <category: 'creation'>
+        con := aCon.
+    ]
+
+    assignmentFailure [
+        "The audio assignment has failed."
+    ]
+
+    assignmentSuccess [
+        "The assignment succeeded and there is now a specific channel"
+    ]
+
+    cancel [
+    ]
+
+    dispatch: aMsg [
+        self subclassResponsibility
+    ]
+
+    nextPutSapi: aMsg [
+        <category: 'output'>
+        ^ self nextPut: (OsmoGSM.BSSAPDTAP initWith: aMsg linkIdentifier: sapi)
+    ]
+
+    nextPut: aMsg [
+        <category: 'output'>
+        con nextPutData: aMsg
+    ]
+
+    logUnknown: aMsg [
+        <category: 'logging'>
+        self logError: 'Unknown message %1' % {aMsg class}.
+    ]
+]
+
+GSMTransaction subclass: GSMLURequest [
+    <comment: 'I handle a Location Updating Request'>
+]
+
+OsmoGSM.SCCPConnectionBase subclass: GSMProcessor [
+    | transactions state endp connId mgcp_trans |
+
+    <comment: 'I am driving a SCCP Connection. This consists of being
+hosting various transactions and dispatching to them.'>
+    <import: OsmoGSM>
+
+    GSMProcessor class >> stateInitial [<category: 'states'> ^ 0 ]
+    GSMProcessor class >> stateAcked   [<category: 'states'> ^ 1 ]
+    GSMProcessor class >> stateRelease [<category: 'states'> ^ 2 ]
+    GSMProcessor class >> stateError   [<category: 'states'> ^ 3 ]
+
+    GSMProcessor class >> createAssignment: aMul timeslot: aTs [
+        | ass |
+        <category: 'audio-connect'>
+        ass := IEMessage initWith: GSM0808Helper msgAssRequest.
+        ass
+            addIe: ((GSM0808ChannelTypeIE
+                    initWith: GSM0808ChannelTypeIE speechSpeech
+                    audio: GSM0808ChannelTypeIE chanSpeechFullPref)
+                        audioCodecs: {GSM0808ChannelTypeIE speechFullRateVersion3.
+                                      GSM0808ChannelTypeIE speechHalfRateVersion3};
+                        yourself);
+            addIe: (GSM0808CICIE initWithMultiplex: aMul timeslot: aTs).
+        ^ ass
+    ]
+
+    initialize [
+        <category: 'creation'>
+        transactions := OrderedCollection new.
+        state := self class stateInitial.
+        ^ super initialize.
+    ]
+
+    data: aData [
+        | msg bssmap data |
+        <category: 'input'>
+
+        "The first message should be a Complete Layer3 Information"
+        [
+            aData data dispatchTrans: self.
+        ] on: Error do: [:e |
+            e logException: 'Failed to dispatch: %1' % {e tag} area: #bsc.
+            self forceClose.
+        ]
+    ]
+
+    bssapUnknownData: aData [
+        <category: 'BSSMAP'>
+        "This is now the GSM data"
+        self forceClose.
+    ]
+
+    mapLayer3: bssap [
+        | layer3 |
+        <category: 'BSSMAP'>
+
+        "Check and move state"
+        'Dispatching GSM' printNl.
+        sem critical: [
+            self verifyState: [state = self class stateInitial].
+            state := self class stateAcked.
+        ].
+
+        "TODO: Add verifications"
+        bssap data findIE: OsmoGSM.GSMCellIdentifier elementId ifAbsent: [
+            ^ self logError: 'CellIdentifier not present on %1' % {self srcRef} area: #msc.
+        ].
+
+        layer3 := bssap data findIE: OsmoGSM.GSMLayer3Info elementId ifAbsent: [
+            ^ self logError: 'Layer3Infor not present on %1' % {self srcRef} area: #msc.
+        ].
+
+        'Dispatching GSM' printNl.
+        sem critical: [self dispatchGSM: layer3 data sapi: 0].
+    ]
+
+    mapClearReq: aData [
+        <category: 'BSSMAP'>
+        'CLEAR Request' printNl.
+
+        sem critical: [
+            self verifyState:
+                [(state > self class stateInitial) and: [state < self class stateError]].
+            self clearCommand: 0.
+        ]
+    ]
+
+    mapClearCompl: aData [
+        <category: 'BSSMAP'>
+        sem critical: [
+            self verifyState: [state = self class stateRelease].
+            self releaseAudio.
+            self release.
+        ].
+    ]
+
+    mapCipherModeCompl: aData [
+        <category: 'BSSMAP'>
+        'CIPHER MODE COMPL' printNl.
+        aData inspect.
+    ]
+
+    terminate [
+        <category: 'private'>
+        "Cancel all transactions"
+        sem critical: [
+            transactions do: [:each |
+                [each cancel] on: Error do: [:e |
+                    e logException: 'GSMProc(srcref:%1) failed cancel: %2' %
+                        {self srcRef. each class} area: #bsc.
+                ]
+            ].
+
+            transactions := OrderedCollection new.
+            self releaseAudio.
+        ].
+    ]
+
+    verifyState: aBlock [
+        <category: 'private'>
+        "Must be locked."
+
+        aBlock value ifFalse: [
+            self logError: 'GSMProc(srcref:%1) wrong state: %2.' % {self srcRef. state} area: #bsc.
+            ^ self error: 'Failed to verify the state.'.
+        ].
+    ]
+
+    forceClose [
+        <category: 'private'>
+        sem critical: [
+            state = self class stateError ifTrue: [
+                "Already closing down"
+                ^ false
+            ].
+
+            state := self class stateError.
+            self release
+        ].
+    ]
+
+    clearCommand: aCause [
+        | msg |
+        <category: 'private'>
+        "Must be locked"
+
+        "Already clearing it once"
+        state >= self class stateRelease ifTrue: [
+            ^ true.
+        ].
+
+        state := self class stateRelease.
+
+        msg := OsmoGSM.IEMessage initWith: OsmoGSM.GSM0808Helper msgClear.
+        msg addIe: (OsmoGSM.GSMCauseIE initWith: aCause).
+        self nextPutData: (OsmoGSM.BSSAPManagement initWith: msg).
+    ]
+
+    checkRelease [
+        "Check if things can be released now"
+        <category: 'private'>
+        "Must be locked"
+
+        "No more transactions, clean things up"
+        transactions isEmpty ifTrue: [
+            self clearCommand: 9.
+        ].
+    ]
+
+    addTransaction: aTran [
+        <category: 'private'>
+        "Must be locked"
+        self logDebug: 'GSMProc(srcref:%1) adding transaction %2' % {self srcRef. aTran class} area: #bsc.
+        transactions add: aTran.
+    ]
+
+    removeTransaction: aTran [
+        <category: 'private'>
+        "Must be locked"
+        self logDebug: 'GSMProc(srcref:%1) removing transaction %2' % {self srcRef. aTran class} area: #bsc.
+        transactions remove: aTran ifAbsent: [
+            self logError: 'GSMProc(srcref:%1) trans not found %2' % {self srcRef. aTran class} area: #bsc.
+        ].
+
+        self checkRelease.
+    ]
+
+    dispatchDTAP: aMsg [
+        <category: 'private'>
+        sem critical: [self dispatchGSM: aMsg data sapi: aMsg sapi]
+    ]
+
+    dispatchGSM: aMsg sapi: aSapi [
+        <category: 'private'>
+        "Must be locked"
+
+        "Find an active transaction for this"
+        transactions do: [:each |
+            (each sapi = aSapi and: [each ti = aMsg ti]) ifTrue: [
+                each dispatch: aMsg.
+                self checkRelease.
+                ^ true.
+            ].
+        ].
+
+        aMsg openTransactionOn: self sapi: 0.
+        self checkRelease.
+    ]
+
+    "Audio handling"
+    allocateEndpoint [
+        <category: 'audio'>
+        "The endpoint allocation is a complicated and async process. It
+         starts with picking a timeslot to the BSC, it continues with trying
+         to assign the timeslot via MGCP, then will send the ASSIGNMENT
+         COMMAND. This means even with multiple phone calls there will be
+         only one assigned timeslot.
+
+         To make things more complicated we might have a CRCX or such
+         pending while we need to tear things down. This means we will
+         need to check in the transaction complete/timeout what we need to
+         do next and also keep a list of transactions."
+
+
+         "Right now only one call is allowed. we have no support of switching
+          calls during the call."
+
+        self trunk critical: [
+            endp ifNotNil: [
+                self logError: 'GSMProc(srcref:%1) already has endpoint.'
+                        % {self srcRef} area: #bsc.
+                ^ nil].
+
+            endp := self trunk allocateEndpointIfFailure: [
+                self logError: 'GSMProc(srcref:%1) no endpoint availabble.'
+                        % {self srcRef} area: #bsc.
+                ^ nil].
+        ].
+    ]
+
+    generateCallId [
+        <category: 'audio'>
+        "I can be up to 32 chars of hexdigits. No need to be globally unique"
+        ^ (Random between: 10000000 and: 999999999) asString
+    ]
+
+    trunk [
+        <category: 'audio'>
+        ^ conManager bsc trunk.
+    ]
+
+    callAgent [
+        <category: 'audio'>
+        ^ conManager msc mgcpCallAgent
+    ]
+
+    selectAudioRoute: aPlan leg: aLeg [
+        ^ conManager msc
+            selectAudioRoute: self plan: aPlan leg: aLeg
+    ]
+
+    releaseAudio [
+        "I try to release things right now."
+        <category: 'audio'>
+        self trunk critical: [
+            endp ifNil: [^self].
+            endp isUnused ifTrue: [^self].
+
+            "Check if we have ever sent a CRCX, if not release it"
+            endp isReserved ifTrue: [
+                endp callId isNil
+                    ifTrue:  [
+                        self logDebug:
+                            'GSMProc(srcref:%1) MGCP CRCX never sent.'
+                                % {self srcRef} area: #bsc.
+                        endp used. endp free]
+                    ifFalse: [
+                        self logDebug:
+                            'GSMProc(srcref:%1) MGCP pending CallID:%2. no release.'
+                                % {self srcRef. endp callId} area: #bsc.].
+                ^ self
+            ].
+
+            (endp isUsed and: [endp callId isNil not]) ifTrue: [
+                self sendDLCX.
+            ].
+        ].
+    ]
+
+    sendAssignment [
+        | ass |
+        <category: 'audio-connect'>
+
+        "TODO: Maybe start a timer but we are guarded here anyway."
+        ass := self class createAssignment: endp multiplex timeslot: endp timeslot - 1.
+        self nextPutData: (BSSAPManagement initWith: ass).
+    ]
+
+    mapAssComplete: aData [
+        <category: 'audio-connect'>
+
+        sem critical: [self trunk critical: [
+            endp callId isNil ifTrue: [self sendCRCX].
+        ]].
+    ]
+
+    mapAssFailure: aData [
+        <category: 'audio-connect'>
+        sem critical: [self trunk critical: [
+            self logError: 'GSMProc(srcref:%1) GSM0808 Assignment failed.'
+                    % {self srcRef} area: #bsc.
+            self assignmentFailure.]]
+    ]
+
+    assignmentSuccess [
+        <category: 'audio-connect'>
+
+        transactions do: [:each |
+            each assignmentSuccess.
+        ]
+    ]
+
+    assignmentFailure [
+        <category: 'audio-connect'>
+        "Tell the transactions that there will be no audio."
+
+        transactions do: [:each |
+            each assignmentFailure.
+        ]
+    ]
+
+    takeLocks: aBlock [
+        <category: 'audio-locking'>
+        "Take the locks in lock-order for audio callbacks"
+        conManager critical: [
+            sem critical: [
+                self trunk critical: [
+                    aBlock value]]]
+    ]
+
+    mgcpQueueTrans: aTrans [
+        <category: 'audio-connect'>
+        mgcp_trans add: aTrans.
+        mgcp_trans size = 1 ifTrue: [
+            aTrans start.]
+    ]
+
+    mgcpTransFinished: aTrans [
+        <category: 'audio-connect'>
+        mgcp_trans first = aTrans ifFalse: [
+            self logError: 'GSMProc(srcref:%1) wrong MGCP transaction finished.'
+                    % {self srcRef} area: #bsc.
+            ^false].
+
+        mgcp_trans removeFirst.
+        mgcp_trans isEmpty ifFalse: [
+            mgcp_trans first start.
+        ].
+    ]
+
+    sendCRCX [
+        | trans crcx |
+        <category: 'audio-connect'>
+        endp callId: self generateCallId.
+        trans := Osmo.MGCPTransaction on: endp of: self callAgent.
+        crcx := (Osmo.MGCPCRCXCommand createCRCX: endp callId: endp callId)
+                    parameterAdd: 'M: recvonly';
+                    yourself.
+        trans command: crcx.
+        trans onResult: [:endp :result |
+            self takeLocks: [self crcxResult: result. self mgcpTransFinished: trans]].
+        trans onTimeout: [:endp |
+            self takeLocks: [self crcxTimeout. self mgcpTransFinished: trans]].
+        mgcp_trans := OrderedCollection with: trans.
+        trans start.
+
+        self logDebug: 'GSMProc(srcref:%1) CRCX on %2 with CallID: %3'
+                % {self srcRef. endp endpointName. endp callId} area: #bsc.
+    ]
+
+    crcxResult: aResult [
+        <category: 'audio-connect'>
+
+        "save the sdp and callId"
+        endp used.
+
+        "Did this succeed?"
+        aResult isSuccess ifFalse: [
+            self logError: 'GSMProc(srcref:%1) CRCX failed aCode: %2'
+                    % {self srcRef. aResult code} area: #bsc.
+            self freeEndpoint.
+            self assignmentFailure.
+            ^ self
+        ].
+
+        "Check if there is a connId"
+        connId := aResult parameterAt: 'I' ifAbsent: [
+            self logError: 'GSMProc(srcref:%1) CRCX lacks connId'
+                    % {self srcRef} area: #bsc.
+            self freeEndpoint.
+            self assignmentFailure.
+            ^ self
+        ].
+
+        "Assign the current SDP file"
+        endp sdp: aResult sdp.
+
+        "Check what to do next"
+        state = self class stateAcked
+            ifTrue:  [
+                self logDebug: 'GSMProc(srcref:%1) CRCX compl(%2) Code: %3.'
+                        % {self srcRef. endp callId. aResult code} area: #bsc.
+                self assignmentSuccess.
+            ]
+            ifFalse: [
+                self logDebug: 'GSMProc(srcref:%1) CRCX compl(%2), call gone.'
+                        % {self srcRef. endp callId} area: #bsc.
+                self releaseAudio.
+            ].
+    ]
+
+    crcxTimeout [
+        <category: 'audio-connect'>
+
+        self logDebug: 'GSMProc(srcref:%1) CRCX timeout on %2 with CallID: %3.'
+                % {self srcRef. endp endpointName. endp callId} area: #bsc.
+
+        "Free the endpoint"
+        endp used.
+        self freeEndpoint.
+
+        "tell transactions. in case we get this late then there are no
+         transactions left and this is a no-op."
+        self assignmentFailure.
+    ]
+
+    freeEndpoint [
+        <category: 'audio-release'>
+
+        endp free.
+        endp := nil.
+        connId := nil.
+    ]
+
+    sdpFile [
+        <category: 'audio-sdp'>
+        ^ endp sdp
+    ]
+
+    sendDLCX [
+        | trans dlcx |
+        <category: 'audio-release'>
+        "I sent the DLCX, I also make the endpoint forget the callid. As this
+         is our indicator that things have been cleared or will be cleared."
+
+        trans := Osmo.MGCPTransaction on: endp of: self callAgent.
+        dlcx := Osmo.MGCPDLCXCommand createDLCX: endp callId: endp callId.
+        endp clearCallId.
+        connId isNil ifFalse: [dlcx parameterAdd: 'I: %1' % {connId}].
+        trans command: dlcx.
+        trans onResult: [:endp :result |
+            self takeLocks: [self dlcxResult: result. self mgcpTransFinished: trans]].
+        trans onTimeout: [:endp |
+            self takeLocks: [self dlcxTimeout. self mgcpTransFinished: trans]].
+        self mgcpQueueTrans: trans.
+    ]
+
+    dlcxResult: aResult [
+        <category: 'audio-release'>
+
+        aResult isSuccess
+            ifTrue: [
+                self logError: 'GSMProc(srcref:%1) DLCX succeeded on endp(%2).'
+                    % {self srcRef. endp endpointName} area: #bsc.
+                self freeEndpoint.]
+            ifFalse: [
+                self logError: 'GSMProc(srcref:%1) DLCX failed on endp(%2).'
+                    % {self srcRef. endp endpointName} area: #bsc.].
+    ]
+
+    dlcxTimeout [
+        <category: 'audio-release'>
+
+        self logError: 'GSMProc(srcref:%1) DLCX timedout Endp(%2) stays blocked.'
+                % {self srcRef. endp endpointName} area: #bsc.
+        endp := nil.
+        connId := nil.
+    ]
+
+    sendMDCX: aSDPRecord state: aState [
+        | trans mdcx |
+        <category: 'audio-modify'>
+
+        trans := Osmo.MGCPTransaction on: endp of: self callAgent.
+        mdcx := Osmo.MGCPMDCXCommand createMDCX: endp callId: endp callId.
+        mdcx
+            parameterAdd: 'I: %1' % {connId};
+            parameterAdd: 'M: %1' % {aState};
+            sdp: aSDPRecord.
+        
+        trans
+            command: mdcx;
+            onResult: [:endp :result |
+                self takeLocks: [self mdcxResult: result. self mgcpTransFinished: trans]];
+            onTimeout: [:endp |
+                self takeLocks: [self mdcxTimeout. self mgcpTransFinished: trans]].
+        self mgcpQueueTrans: trans.
+    ]
+
+    mdcxResult: aResult [
+    ]
+
+    mdcxTimeout: aTimeout [
+    ]
+]
diff --git a/src/HLR.st b/src/HLR.st
new file mode 100644
index 0000000..1e5f3d9
--- /dev/null
+++ b/src/HLR.st
@@ -0,0 +1,72 @@
+"
+ (C) 2010 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+"
+This is the interface to the local HLR. It consists out of simple
+data that will be used inside the HLR.
+"
+
+Object subclass: HLRSubscriber [
+    |imsi msisdn vlrnumber auKey name |
+    <category: 'osmo-msc'>
+    <comment: 'I am one subscriber in the HLR'>
+
+    imsi      [ <category: 'accessing'> ^ imsi      ]
+    msisdn    [ <category: 'accessing'> ^ msisdn    ]
+    vlrnumber [ <category: 'accessing'> ^ vlrnumber ]
+    aukey     [ <category: 'accessing'> ^ auKey     ]
+    name      [ <category: 'accessing'> ^ name      ]
+]
+
+Object subclass: HLR [
+    <category: 'osmo-msc'>
+    <comment: 'I am a HLR and I can find subscribers'>
+
+    findSubscriberByIMSI: aIMSI [
+        <category: 'accessing'>
+        ^ self subclassResponsibility
+    ]
+
+    updateVLRNumber: aIMSI number: aNumber [
+        ^ self subclassResponsibility
+    ]
+]
+
+HLR subclass: HLRLocalCollection [
+    | subs |
+    <category: 'osmo-msc-simple'>
+    <comment: 'I am a very simple local HLR'>
+
+    findSubscriberByIMSI: aIMSI [
+        <category: 'accessing'>
+        self subs do: [:each |
+            (each imsi = aIMSI)
+                ifTrue: [^each]].
+
+        ^ nil
+    ]
+
+    addSubscriber: aIMSI [
+        | sub |
+        sub := HLRSubscriber new.
+        sub instVarNamed: #imsi put: aIMSI.
+
+        self subs add: sub.
+    ]
+
+    subs [<category: 'private'> ^subs ifNil: [subs := OrderedCollection new]]
+]
diff --git a/src/Logging.st b/src/Logging.st
new file mode 100644
index 0000000..73378db
--- /dev/null
+++ b/src/Logging.st
@@ -0,0 +1,61 @@
+"
+ (C) 2010 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader fileInPackage: 'OsmoLogging'.
+
+Osmo.LogArea subclass: LogAreaBSC [
+    <category: 'osmo-msc-logging'>
+    LogAreaBSC class >> areaName [ ^ #bsc ]
+    LogAreaBSC class >> areaDescription [ ^ 'BSC Connectivty' ]
+    LogAreaBSC class >> default [
+        ^ self new
+            enabled: true;
+            minLevel: Osmo.LogLevel debug;
+            yourself
+    ]
+]
+
+Osmo.LogArea subclass: LogAreaHLR [
+    <category: 'osmo-msc-logging'>
+    LogAreaHLR class >> areaName [ ^ #hlr ]
+    LogAreaHLR class >> areaDescription [ ^ 'HLR work' ]
+    LogAreaHLR class >> default [
+        ^ self new
+            enabled: true; minLevel: Osmo.LogLevel debug; yourself.
+    ]
+]
+
+Osmo.LogArea subclass: LogAreaVLR [
+    <category: 'osmo-msc-logging'>
+    LogAreaVLR class >> areaName [ ^ #vlr ]
+    LogAreaVLR class >> areaDescription [ ^ 'VLR work' ]
+    LogAreaVLR class >> default [
+        ^ self new
+            enabled: true; minLevel: Osmo.LogLevel debug; yourself.
+    ]
+]
+
+Osmo.LogArea subclass: LogAreaMSC [
+    <category: 'osmo-msc-logging'>
+    LogAreaMSC class >> areaName [ ^ #msc ]
+    LogAreaMSC class >> areaDescription [ ^ 'MSC work' ]
+    LogAreaMSC class >> default [
+        ^ self new
+            enabled: true; minLevel: Osmo.LogLevel debug; yourself.
+    ]
+]
diff --git a/src/MSC.st b/src/MSC.st
new file mode 100644
index 0000000..be2f3e0
--- /dev/null
+++ b/src/MSC.st
@@ -0,0 +1,242 @@
+"
+ (C) 2010-2011 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader
+    fileInPackage: 'OsmoMGCP';
+    fileInPackage: 'OsmoSIP'.
+
+Object subclass: MSCConfig [
+    | ip port mgcp sip_ip sip_port |
+    <category: 'MSC-IP'>
+    <comment: 'I contain a very simple MSC config for IP based BSCs'>
+
+    bscIP: aIP [
+        <category: 'config'>
+        ip := aIP
+    ]
+
+    bscIP [
+        <category: 'accessing'>
+        ^ ip
+    ]
+
+    bscPort: aPort [
+        <category: 'config'>
+        port := aPort
+    ]
+
+    bscPort [
+        <category: 'accessing'>
+        ^ port
+    ]
+
+    mgcpIP: aIP [
+        <category: 'config'>
+        mgcp := aIP
+    ]
+
+    mgcpIP [
+        <category: 'accessing'>
+        ^ mgcp ifNil: [ip]
+    ]
+
+    sipIP: aIP [
+        <category: 'config'>
+        sip_ip := aIP
+    ]
+
+    sipIP [
+        <category: 'accessing'>
+        ^ sip_ip ifNil: [ip]
+    ]
+
+    sipPort: aPort [
+        <category: 'config'>
+        sip_port := aPort
+    ]
+
+    sipPort [
+        <category: 'accessing'>
+        ^ sip_port ifNil: [5061]
+    ]
+]
+
+Object subclass: MSCBSCConnectionHandler [
+    | msc connections |
+
+    <comment: 'I take incoming connections, find a handler for them and
+    will register them. I will be passed to the BSCListener'>
+
+    MSCBSCConnectionHandler class >> initWith: aMSC [
+        ^ self new
+                instVarNamed: #msc put: aMSC; yourself
+    ] 
+
+    connections [ ^ connections ifNil: [connections := OrderedCollection new]]
+
+    setupConnection: aConnection on: aConfig [
+        | bsc |
+        self logNotice: 'BSC-Socket: New Connection for lac', (aConfig lac asString)
+             area: #bsc.
+
+        "Create the BSC first and then assume it is present"
+        [
+            bsc := BSCIPAConnection createOn: aConnection withConfig: aConfig msc: msc.
+        ] on: Exception do: [:ex |
+            ex logException: 'BSC: Creating a handler failed.' area: #bsc.
+            aConnection close.
+            ^ false
+        ].
+
+
+        [
+            [[
+                aConfig connected: true.
+                self connections add: bsc.
+                bsc process. 
+            ] on: SystemExceptions.EndOfStream do: [:ex |
+                aConfig connected: false.
+                self logNotice: 'BSC disconnected for lac: %1' % {aConfig lac}
+                     area: #bsc.
+            ] on: Exception do: [:ex |
+                self logError: 'Unexpected exception for lac: %1' % {aConfig lac}
+                    area: #bsc.
+                thisContext backtraceOn: Transcript.
+            ]] ensure: [
+                self logNotice: 'BSC being disconnected for lac: %1' % {aConfig lac}
+                    area: #bsc. 
+                bsc terminateAll.
+                self connections remove: bsc ifAbsent: [
+                    self logError: 'BSC was never added on lac: %1?' % {aConfig lac}
+                        area: #bsc].
+
+                aConfig connected: false.
+                aConnection close.
+            ].
+        ] fork.  
+    ]
+
+    newConnection: aConnection [
+        | peer |
+        <category: 'handling'>
+
+        peer := aConnection remoteAddress.
+        msc bscConfig bscList do: [:each |
+            each peer = peer ifTrue: [
+                each connected ifTrue: [
+                    self logError: 'BSC-Socket: Still connected for lac: %1' % {each lac}
+                            area: #bsc.
+                    aConnection close.
+                    ^ false
+                ].
+
+                self setupConnection: aConnection on: each.
+                ^ true
+            ].
+        ].
+
+        self logError: 'BSC-Socket: Unknown connection from %1' % {peer} area: #bsc.
+        aConnection close.
+    ]
+]
+
+Object subclass: MSCApplication [
+    | hlr vlr config bscListener bscConfig bscConHandler mgcp sip |
+    <comment: 'I am a MSC as I have the VLR/HLR and other instances'>
+
+    hlr [ ^ hlr ifNil: [HLRLocalCollection new]]
+    vlr [ ^ vlr ifNil: [VLRLocalCollection new]]
+
+    config [ ^ config ifNil: [config := MSCConfig new]]
+    bscConfig [ ^ bscConfig ifNil: [bscConfig := BSCConfig new]]
+    bscConHandler [ ^ bscConHandler ifNil: [bscConHandler := MSCBSCConnectionHandler initWith: self]]
+
+    mgcpCallAgent [
+        <category: 'MGCP-Audio'>
+        ^ mgcp ifNil: [
+            mgcp := (Osmo.MGCPCallAgent startOn: config bscIP)
+                start;
+                yourself]
+    ]
+
+    sipGateway [
+        <category: 'SIP-Audio'>
+        ^ sip ifNil: [ | transport |
+            transport := Osmo.SIPUdpTransport
+                            startOn: self config sipIP port: self config sipPort.
+            sip := Osmo.SIPUserAgent createOn: transport.
+            transport start.
+            sip]
+    ]
+
+    selectAudioRoute: aCon plan: aPlan leg: aLeg [
+        | nr |
+        "TODO: Very simple and hardcoded rule"
+        nr := aPlan number.
+
+        "No number, let us return"
+        nr isEmpty ifTrue: [^nil].
+
+        "No special number"
+        nr first = $* ifFalse: [^nil].
+
+
+        ^ (SIPMTCall
+            fromUser: 'sip:1000@sip.zecke.osmocom.org'
+            host: '127.0.0.1'
+            port: 5060
+            to: 'sip:1%1@127.0.0.1' % {nr allButFirst}
+            on: self sipGateway)
+            remoteLeg: aLeg;
+            yourself
+    ]
+
+    serveBSC [
+        "I will start to listen for BSCs"
+        bscListener ifNotNil: [bscListener stop.].
+        bscListener := BSCListener
+                        initWith: config bscIP
+                        port: config bscPort
+                        handler: self bscConHandler.
+        bscListener serve.
+    ]
+
+
+    MSCApplication class >> startExample [
+        | msc |
+
+        msc := MSCApplication new.
+        msc config
+            bscIP: '0.0.0.0';
+            bscPort: 5000;
+            sipIP: '192.168.0.101'.
+        msc bscConfig
+            addBSC: '127.0.0.1' withName: 'test' andLac: 4711.
+
+        "Make sure MGCP is running"
+        msc mgcpCallAgent.
+
+        "Make sure we handle SIP"
+        msc sipGateway.
+
+        msc logNotice: 'Serving BSCs now' area: #msc.
+        [msc serveBSC. 'MSC has exited' printNl] fork.
+
+        ^ msc.
+    ]
+]
diff --git a/src/SIPCall.st b/src/SIPCall.st
new file mode 100644
index 0000000..8fec1f9
--- /dev/null
+++ b/src/SIPCall.st
@@ -0,0 +1,81 @@
+"
+ (C) 2010-2011 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader fileInPackage: 'OsmoSIP'.
+
+Osmo.SIPCall subclass: SIPMTCall [
+    | remoteLeg sdp_alert |
+    <category: 'sip'> 
+    <comment: 'I represent a SIP terminated call. It is called Mobile
+    Terminated to stay with the GSM speech.'>
+
+    remoteLeg: aLeg [
+        <category: 'creation'>
+        remoteLeg := aLeg.
+    ]
+
+    netTerminate [
+        <category: 'external'>
+        "The other side of the call has terminated, we need to
+        clean up things."
+
+        remoteLeg := nil.
+        self terminate.
+    ]
+
+    sessionNew [
+        "We now have connected call, tell the other side."
+        remoteLeg isNil
+            ifFalse:  [remoteLeg netConnect]
+            ifTrue: [self terminate].
+    ]
+
+    sessionFailed [
+        "We have failed to connect things, tell the other side."
+        self terminateRemote.
+    ]
+
+    sessionEnd [
+        "The session is now disconnected, tell the other side."
+        self terminateRemote.
+    ]
+
+    sessionNotification: aNot [
+        "The session has some information. We will use it to tell
+        the other leg of the connection."
+        (aNot code asInteger = 183) ifTrue: [
+            remoteLeg isNil ifFalse: [
+                sdp_alert := aNot sdp.
+                remoteLeg netAlerting]].
+    ]
+
+    terminateRemote [
+        remoteLeg isNil
+            ifFalse: [remoteLeg netTerminate. remoteLeg := nil].
+    ]
+
+    sdp [
+        <category: 'audio'>
+        ^ sdp_result
+    ]
+
+    sdpAlert [
+        <category: 'audio'>
+        ^ sdp_alert
+    ]
+] 
diff --git a/src/VLR.st b/src/VLR.st
new file mode 100644
index 0000000..cf9d403
--- /dev/null
+++ b/src/VLR.st
@@ -0,0 +1,109 @@
+"
+ (C) 2010 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+"
+This is the interface to the VLR
+"
+
+Object subclass: VLRSubscriber [
+    |imsi tmsi msisdn lac|
+    <category: 'osmo-msc'>
+    <comment: 'I am one subscriber in the VLR'>
+    
+
+    imsi   [ <category: 'accessing'> ^ imsi   ]
+    tmsi   [ <category: 'accessing'> ^ tmsi   ]
+    msisdn [ <category: 'accessing'> ^ msisdn ]
+    lac    [ <category: 'accessing'> ^ lac    ]
+]
+
+Object subclass: VLR [
+    <category: 'osmo-msc'>
+    <comment: 'I hold the active subscribers'>
+
+    activeSubscribers [
+        <category: 'accessing'>
+        ^ self subclassResponsibility
+    ]
+
+    activeSubscribersByLAC: aLac [
+        <category: 'accessing'>
+        ^ self activeSubscribers
+                reject: [:each | each ~= aLac ].
+    ]
+
+    findSubscriber: aMatch ifAbsent: aBlock [
+        <category: 'private'>
+
+        self activeSubscribers do: [:each |
+            (aMatch value: each)
+                ifTrue: [^each].
+        ].
+
+        ^ aBlock value.
+    ]
+
+    findSubscriberByIMSI: aIMSI ifAbsent: aBlock [
+        <category: 'accessing'>
+        ^ self findSubscriber: [:each | each imsi = aIMSI] ifAbsent: aBlock.
+    ]
+
+    findSubscriberByTMSI: aTMSI ifAbsent: aBlock [
+        <category: 'accessing'>
+        ^ self findSubscriber: [:each | each tmsi = aTMSI] ifAbsent: aBlock.
+    ]
+
+    insertSubscriber: aIMSI [
+        ^ self subclassResponsibility
+    ]
+]
+
+Object subclass: HLRResolver [
+    insertSubscriber: aIMSI [
+        ^ self subclassResponsibility
+    ]
+]
+
+VLR subclass: VLRLocalCollection [
+    | subs resolver |
+
+    VLRLocalCollection class >> initWith: aResolver [
+        ^ self new
+            instVarNamed: #resolver put: aResolver;
+            yourself.
+    ]
+
+    insertSubscriber: aIMSI [
+        | hlr sub |
+        hlr := resolver insertSubscriber: aIMSI.
+        hlr ifNil: [^false].
+
+        sub := self findSubscriberByIMSI: aIMSI
+                    ifAbsent: [ | sub |
+                        sub := VLRSubscriber new
+                            instVarNamed: #imsi put: aIMSI; yourself.
+                    self subs add: sub].
+        ^ true
+    ]
+
+    activeSubscribers [
+        <category: 'accessing'>
+        ^ self subs
+    ]
+
+    subs [ <category: 'private'> ^ subs ifNil: [subs := OrderedCollection new]]
+]