osmo-st-gsm/SCCPHandler.st

PackageLoader fileInPackage: 'OsmoNetwork'.

Object subclass: SCCPConnection [
    | src dst queue |

    srcRef [
        ^ src
    ]
    srcRef: aRef [
        src := aRef
    ]

    dstRef: aRef [
        dst := aRef
    ]

    enqueueForRead: aMsg [
        self queue next: aMsg.
    ]

    readQueue [
        ^ queue ifNil: [ queue := SharedQueue new. ]
    ]
]

Object subclass: MSGParser [
    <comment: 'I take a SCCP message and recursively parse all the data'>

    MSGParser class >> parse: aByteArray [
        | sccp |
        "Return a completely decoded subtree"

        sccp := Osmo.SCCPMessage decode: aByteArray.
        (sccp respondsTo: #data)
            ifTrue: [
                sccp data: (self decodeBSSAP: sccp data).
        ].

        ^ sccp
    ]

    MSGParser class >> decodeBSSAP: aData [
        | bssap |
        bssap := BSSAPMessage decode: aData.
        bssap class msgType = BSSAPDTAP msgType
            ifTrue: [
                bssap data: (GSM48MSG decode: bssap data)
            ]
            ifFalse: [
                bssap data: (self decodeBSSMAP: bssap data).
            ].

        ^ bssap
    ]

    MSGParser class >> decodeBSSMAP: aData [
        | bssmap |
        bssmap := IEMessage decode: aData with: GSM0808IE.
        bssmap findIE: (GSMLayer3Info elementId) ifPresent: [:each |
            each data: (GSM48MSG decode: each data).
        ].
        ^ bssmap
    ]

]

Object subclass: SCCPHandler [
    | connections last_ref |
    <comment: 'I handle SCCP messages'>

    registerOn: aDispatcher [
        aDispatcher addHandler: Osmo.IPAConstants protocolSCCP
                    on: self with: #handleMsg:.
    ]

    handleMsg: aMsg [
        | sccp |

        'Got a new SCCP message here.' printNl.

        [
            sccp := MSGParser parse: (aMsg asByteArray).
            sccp inspect.
            sccp printNl.
            sccp class printNl.
        ] on: Exception do: [
            self logError: 'Failed to parse message' area: #sccp.
            aMsg asByteArray printNl.
        ]
    ]

    createConnection: aData [
        | con res|

        con := SCCPConnection new.
        con srcRef: self assignSrcRef.
        res := Osmo.SCCPConnectionRequest
                initWith: (con srcRef) dest: (Osmo.SCCPAddress createWith: 254) data: aData.
        self connections add: con.

        ^ res
    ]

    assignSrcRef [
        ^ 666
    ]

    connections [
        ^ connections ifNil: [ connections := OrderedCollection new. ]
    ]
]