mgmtapi.c

windows的snmp api源码

                    SNMP_LOG_ERROR,
                    "MGMTAPI: Ignoring invalid pdu type %d.\n",
                    nPduType
                    ));

                // continue
                fDone = FALSE;
            }

        } else {

            SNMPDBG((
                SNMP_LOG_ERROR,
                "MGMTAPI: SnmpGetPduData returned %d.\n",
                SnmpGetLastError(pSMS->hSnmpSession)
                ));

            // retrieve last error status from winsnmp
            pSMS->nLastError = SnmpGetLastError(pSMS->hSnmpSession);
        }

        // release temporary entity
        SnmpFreeEntity(hAgentEntity);

        // release temporary entity
        SnmpFreeEntity(hManagerEntity);

        // release temporary context
        SnmpFreeContext(hViewContext);

    } else {

        SNMPDBG((
            SNMP_LOG_ERROR,
            "MGMTAPI: SnmpRecvMsg returned %d.\n",
            SnmpGetLastError(pSMS->hSnmpSession)
            ));

        // retrieve last error status from winsnmp
        pSMS->nLastError = SnmpGetLastError(pSMS->hSnmpSession);
    }

    // release pdu
    FreePdu(pSMS);

    return fDone;
}


LRESULT
CALLBACK
NotificationWndProc(
    HWND   hWnd,
    UINT   uMsg,
    WPARAM wParam,
    LPARAM lParam
    )

/*++

Routine Description:

    Callback that processes WinSNMP notifications.

Arguments:

    hWnd - window handle.

    uMsg - message identifier.

    wParam - first message parameter.

    lParam - second message parameter.

Return Values:

    The return value is the result of the message processing and
    depends on the message sent.

--*/

{
    // check for winsnmp notification
    if (uMsg == WM_WSNMP_INCOMING) {

        PSNMP_MGR_SESSION pSMS;

        // retrieve mgmtapi session pointer from window
        pSMS = (PSNMP_MGR_SESSION)GetWindowLongPtr(hWnd, 0);

        // validate session ptr
        WSNMP_ASSERT(pSMS != NULL);

        // process notification message
        if (NotificationCallback(pSMS)) {

            // post message to break out of message pump
            PostMessage(pSMS->hWnd, WM_WSNMP_DONE, (WPARAM)0, (LPARAM)0);
        }

        return (LRESULT)0;

    } else {

        // forward all other messages to windows
        return DefWindowProc(hWnd, uMsg, wParam, lParam);
    }
}


BOOL
RegisterNotificationClass(
    )

/*++

Routine Description:

    Register notification class for sessions.

Arguments:

    None.

Return Values:

    Returns true if successful.

--*/

{
    BOOL fOk;
    WNDCLASS wc;

    // initialize notification window class
    wc.lpfnWndProc   = (WNDPROC)NotificationWndProc;
    wc.lpszClassName = NOTIFICATION_CLASS;
    wc.lpszMenuName  = NULL;
    wc.hInstance     = g_hDll;
    wc.hIcon         = NULL;
    wc.hCursor       = NULL;
    wc.hbrBackground = NULL;
    wc.cbWndExtra    = sizeof(PSNMP_MGR_SESSION);
    wc.cbClsExtra    = 0;
    wc.style         = 0;

    // register class
    fOk = RegisterClass(&wc);

    if (!fOk) {

        SNMPDBG((
            SNMP_LOG_ERROR,
            "MGMTAPI: RegisterClass returned %d.\n",
            GetLastError()
            ));
    }

    return fOk;
}


BOOL
UnregisterNotificationClass(
    )

/*++

Routine Description:

    Unregister notification class.

Arguments:

    None.

Return Values:

    Returns true if successful.

--*/

{
    BOOL fOk;

    // unergister notification window class
    fOk = UnregisterClass(NOTIFICATION_CLASS, g_hDll);

    if (!fOk) {

        SNMPDBG((
            SNMP_LOG_ERROR,
            "MGMTAPI: UnregisterClass returned %d.\n",
            GetLastError()
            ));
    }

    return fOk;
}


BOOL
StartSnmpIfNecessary(
    )

/*++

Routine Description:

    Initialize WinSNMP DLL if necessary.

Arguments:

    None.

Return Values:

    Returns true if successful.

--*/

{
    BOOL fOk = TRUE;

    // serialize access to startup code
    EnterCriticalSection(&g_GlobalLock);

    // see if already started
    if (g_fIsSnmpStarted != TRUE) {

        SNMPAPI_STATUS status;

        // initialize start params
        smiUINT32 nMajorVersion   = 0;
        smiUINT32 nMinorVersion   = 0;
        smiUINT32 nLevel          = 0;
        smiUINT32 nTranslateMode  = 0;
        smiUINT32 nRetransmitMode = 0;

        // start winsnmp
        status = SnmpStartup(
                    &nMajorVersion,
                    &nMinorVersion,
                    &nLevel,
                    &nTranslateMode,
                    &nRetransmitMode
                    );

        // validate return code
        if (WSNMP_SUCCEEDED(status)) {

            SNMPDBG((
                SNMP_LOG_TRACE,
                "MGMTAPI: SnmpStartup succeeded:\n"
                "MGMTAPI:\tnMajorVersion   = %d\n"
                "MGMTAPI:\tnMinorVersion   = %d\n"
                "MGMTAPI:\tnLevel          = %d\n"
                "MGMTAPI:\tnTranslateMode  = %d\n"
                "MGMTAPI:\tnRetransmitMode = %d\n",
                nMajorVersion,
                nMinorVersion,
                nLevel,
                nTranslateMode,
                nRetransmitMode
                ));

            // allocate global trap available event
            g_hTrapEvent = CreateEvent(NULL, FALSE, FALSE, NULL);

            // allocate global event to sync. SnmpMgrTrapListen
            g_hTrapRegisterdEvent = CreateEvent(NULL, FALSE, FALSE, NULL);

            // make sure translate mode is snmp v1
            SnmpSetTranslateMode(SNMPAPI_UNTRANSLATED_V1);

            // make sure retransmit mode is on
            SnmpSetRetransmitMode(SNMPAPI_ON);

            // register notification class
            RegisterNotificationClass();

            // save new status
            g_fIsSnmpStarted = TRUE;

            // success
            fOk = TRUE;

        } else {

            SNMPDBG((
                SNMP_LOG_ERROR,
                "MGMTAPI: SnmpStartup returned %d.\n",
                SnmpGetLastError((HSNMP_SESSION)NULL)
                ));

            // failure
            fOk = FALSE;
        }
    }

    // serialize access to startup code
    LeaveCriticalSection(&g_GlobalLock);

    return fOk;
}


BOOL
CleanupIfNecessary(
    )

/*++

Routine Description:

    Cleanup WinSNMP DLL if necessary.

Arguments:

    None.

Return Values:

    Returns true if successful.

--*/

{
    BOOL fOk = TRUE;

    // serialize access to startup code
    EnterCriticalSection(&g_GlobalLock);

    // see if already started
    if (g_fIsSnmpStarted == TRUE) {

        SNMPAPI_STATUS status;

        // shutdown winsnmp
        status = SnmpCleanup();

        // validate return code
        if (WSNMP_FAILED(status)) {

            SNMPDBG((
                SNMP_LOG_ERROR,
                "MGMTAPI: SnmpCleanup returned %d.\n",
                SnmpGetLastError((HSNMP_SESSION)NULL)
                ));

            // failure
            fOk = FALSE;
        }

        // unregister notification class
        UnregisterNotificationClass();

        // save new status
        g_fIsSnmpStarted = FALSE;
    }

    // check trap handle
    if (g_hTrapEvent != NULL) {

        // close trap handle
        CloseHandle(g_hTrapEvent);

        // re-initialize
        g_hTrapEvent = NULL;
    }

    // serialize access to startup code
    LeaveCriticalSection(&g_GlobalLock);

    return fOk;
}


BOOL
CreateNotificationWindow(
    PSNMP_MGR_SESSION pSMS
    )

/*++

Routine Description:

    Create notification window for session.

Arguments:

    pSMS - pointer to MGMTAPI session structure.

Return Values:

    Returns true if successful.

--*/

{
    BOOL fOk;

    // validate session ptr
    WSNMP_ASSERT(pSMS != NULL);

    // create notification window
    pSMS->hWnd = CreateWindow(
                    NOTIFICATION_CLASS,
                    NULL,       // pointer to window name
                    0,          // window style
                    0,          // horizontal position of window
                    0,          // vertical position of window
                    0,          // window width
                    0,          // window height
                    NULL,       // handle to parent or owner window
                    NULL,       // handle to menu or child-window identifier
                    g_hDll,     // handle to application instance
                    NULL        // pointer to window-creation data
                    );

    // validate window handle
    if (pSMS->hWnd != NULL) {

        // store pointer to session in window
        SetWindowLongPtr(pSMS->hWnd, 0, (LONG_PTR)pSMS);

        // success
        fOk = TRUE;

    } else {

        SNMPDBG((
            SNMP_LOG_ERROR,
            "MGMTAPI: CreateWindow returned %d.\n",
            GetLastError()
            ));

        // failure
        fOk = FALSE;
    }

    return fOk;
}


BOOL
DestroyNotificationWindow(
    HWND hWnd
    )

/*++

Routine Description:

    Destroy notification window for session.

Arguments:

    hWnd - window handle for session.

Return Values:

    Returns true if successful.

--*/

{
    BOOL fOk;

    // destroy notification window
    fOk = DestroyWindow(hWnd);

    if (!fOk) {

        SNMPDBG((
            SNMP_LOG_ERROR,
            "MGMTAPI: DestroyWindow returned %d.\n",
            GetLastError()
            ));
    }

    return fOk;
}


BOOL
CloseSession(
    PSNMP_MGR_SESSION pSMS
    )

/*++

Routine Description:

    Close WinSNMP session associated with MGMTAPI session.

Arguments:

    pSMS - pointer to MGMTAPI session structure.

Return Values:

    Returns true if successful.

--*/

{
    BOOL fOk = TRUE;
    SNMPAPI_STATUS status;

    // validate session ptr
    WSNMP_ASSERT(pSMS != NULL);

    // check if window opened
    if (pSMS->hWnd != (HWND)NULL) {

        // destroy notification window
        fOk = DestroyNotificationWindow(pSMS->hWnd);
    }

    // check if agent entity allocated
    if (pSMS->hAgentEntity != (HSNMP_ENTITY)NULL) {

        // close the entity handle
        status = SnmpFreeEntity(pSMS->hAgentEntity);

        // validate status
        if (WSNMP_FAILED(status)) {

            SNMPDBG((
                SNMP_LOG_ERROR,
                "MGMTAPI: SnmpFreeEntity returned %d.\n",