wsnmputil.cpp

简单网络管理的应用,适用于初学snmp的人。

/*
Module Name: wsnmputil.cpp
Abstract:

    Command Line utility to query the SNMP agent using WINSNMP API.

--*/ 

#include  <stdio.h>
#include  <string.h>
#include  <stdlib.h>
#include  <winsock2.h>
#include  <winsnmp.h>
#include  <snmp.h>
#include  <mgmtapi.h>
#include "WSnmpUtil.h"
#include  "wsnmputil.h"
#pragma comment( lib, "Ws2_32.lib")
//外部全局变量gVars，记录用户命令等信息
GlobalVars    gVars;
// 
// abstract: main entry point.
// input arguments:
// argc->number of input arguments
// argv->array of strings ( containing argc number of arguments )
// output: return status.
//
int __cdecl main( int argc, char **argv )
{
    //初试化一般参数
    PSNMP_MGR_SESSION    pSession = NULL;
    int                  nReturn = 0;
    BOOL                 result;
    int                  i = 0;
    smiVALUE             lvalue;
    SNMPAPI_STATUS       status;
    WSAData              wsaData;
     //初试化SNMP参数
    
    smiUINT32 nMajorVersion   = 0;
    smiUINT32 nMinorVersion   = 0;
    smiUINT32 nLevel          = 0;

    smiUINT32 nTranslateMode  = 0;
    smiUINT32 nRetransmitMode = 0;

    __try 
    {
        //SNMPAPI_UNTRANSLATED_V1 & SNMPAPI_UNTRANSLATED_V2 require transport address
        //and we will use winsock api to get transport address from host names
        if ( WSAStartup( 0x202, &wsaData ) != 0 )
        {
            nReturn = -1;
            __leave;
        }

        // WinSnmp is supported on Windows NT 5.0 or later.
		//判断windows NT 的版本
        OSVERSIONINFO osvi;

        memset(&osvi, 0, sizeof(OSVERSIONINFO));
        osvi.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
        GetVersionEx (&osvi);
        if (osvi.dwPlatformId == VER_PLATFORM_WIN32_NT)
        {
            if (osvi.dwMajorVersion <= 4)
            { 
                PrintDbgMessage( "wsnmputil: WinSnmp is supported on Windows NT 5.0 or later ..\n" );
                nReturn = -1;
                __leave;
            }
        }
        else    
        {
            PrintDbgMessage( "wsnmputil: WinSnmp is supported on Windows NT 5.0 or later ..\n" );
            nReturn = -1;
            __leave;
        }


         //接收用户在命令行输入的命令，主要记录在变量gVars中
        result = ParseCommandLine( argc, argv );
        if ( result == FALSE )
        {
            nReturn = -1;
            __leave;
        }
        //********************************************************//
		//加载SNMP服务
		//********************************************************//
        // start winsnmp
        status = SnmpStartup(
                      &nMajorVersion, //SNMP主版本号
                      &nMinorVersion, //SNMP副版本号
                      &nLevel,        //支持的最高操作标准
                      &nTranslateMode, //默认的上下文传输模式
                      &nRetransmitMode  //默认的重发机制
                      );
        
		//分两种情况设置传输模式(SNMP1/SNMP2)
        if ( !SNMP_FAILURE(status) ) 
        {
            if ( gVars.version == FALSE )
                SnmpSetTranslateMode( SNMPAPI_UNTRANSLATED_V1 );  //设置传输模式1
            else
                SnmpSetTranslateMode( SNMPAPI_UNTRANSLATED_V2 ); //设置传输模式2
        }
        else
        {
            nReturn = -1;
            __leave;
        }
        //为会话分配内存空间
        pSession = ( PSNMP_MGR_SESSION )SnmpUtilMemAlloc( sizeof( SNMP_MGR_SESSION ) );

        if ( pSession == NULL )
        {
            PrintDbgMessage( "wsnmputil: Memory allocation failed ..\n" );
            nReturn = -1;
            __leave;
        }
        //*创建一个隐藏的负责监听WinSNMP消息的窗口
        if ( !CreateNotificationWindow( pSession ) )
        {
            PrintDbgMessage( "wsnmputil: Fail to create notification window ..\n" );
            nReturn = -1;
            __leave;
        }

        result = OpenWinSNMPSession( pSession );

        if ( result == FALSE )
        {
            PrintDbgMessage( "wsnmputil: Open session failed ..\n" );
            nReturn = -1;
            __leave;
        }
        //判断是那个操作Get，GetNext，Set,GetBulk,Walk
        switch (gVars.operation)
        {
            case TRAP:
                // WaitForTraps will block in While (ProcessAgentResponse()) loop
                // Util user hits Ctrl+C to exit the program
                WaitForTraps( pSession );
                break;

            case WALK:
                while ( pSession->nErrorStatus == SNMP_ERROR_NOERROR )
                {
                    if ( ! ( result = CreatePduSendRequest( pSession, NULL ) ) )
                        break;
                    if ( gVars.fDone == TRUE )
                        break;
                }
                break;

            case GET:
            case GET_NEXT:
                // do create a pdu and send a request.
                for( i = 0; i < gVars.oidCount; i++ )
                    result = CreatePduSendRequest( pSession, NULL );
                break;

            case GET_BULK:
                result = CreatePduSendRequest( pSession, NULL );
                break;

            case SUB_TREE:
                while ( pSession->nErrorStatus == SNMP_ERROR_NOERROR )
                {           
                    result = CreatePduSendRequest( pSession, NULL );

                    // check the return status.
                    if ( result == FALSE )
                       break;

                    // check if we hit the end of the subtree ..
                    if ( gVars.fDone == TRUE )
                        break;
                }
                break;

            case SET:
                result = FALSE;
                gVars.doSet = TRUE;

                if ( gVars.pSetValue != NULL )
                {
                    gVars.operation = GET;
                    result = CreatePduSendRequest( pSession, NULL );
                }
            
                if ( result != FALSE )
                {
                    gVars.operation = SET;

                    // copy the object type. Ex: INT UINT32 etc..               
                    lvalue.syntax = gVars.value.syntax;

                    ConvertStringToSmiValue( &lvalue );

                    result = CreatePduSendRequest( pSession, &lvalue );
        
                    // check the error status on pSession.
                    if( pSession->nErrorStatus != 0 )
                        PrintDbgMessage( "Failed in setting the OID value ..\n" );
                    else
                        PrintDbgMessage( "Succeeded in setting the OID value ..\n" );

                }
                break;

        }  //end switch

    }  // end try block
    __finally
    {
        // free memory ..    
        for( i = 0; i < gVars.oidCount; i++ )
        {
            if ( gVars.pszOid[ i ] )
                SnmpUtilMemFree( gVars.pszOid[ i ] );
        }

        if ( gVars.pAgentStrAddr )
            SnmpUtilMemFree( gVars.pAgentStrAddr );

        if ( gVars.pAgentStrAddr != NULL )
            SnmpUtilMemFree( gVars.pAgentCommunity );
    
        if ( gVars.pSetValue )
            SnmpUtilMemFree( gVars.pSetValue );

        if ( 
            ( ( lvalue.syntax == SNMP_SYNTAX_OCTETS )    
             || ( lvalue.syntax == SNMP_SYNTAX_BITS )        
             || ( lvalue.syntax == SNMP_SYNTAX_OPAQUE )    
             || ( lvalue.syntax == SNMP_SYNTAX_IPADDR )    
             || ( lvalue.syntax == SNMP_SYNTAX_OID ) ) 
             &&  lvalue.value.string.ptr )
        {
            SnmpUtilMemFree (lvalue.value.string.ptr);
        }

        // close the winsnmp session
        CloseWinSNMPSession ( pSession );

        if ( pSession ) SnmpUtilMemFree( pSession );

        // do SnmpCleanup( )
        SnmpCleanup( );

        // shut off windows sockets.
        WSACleanup( );

    }  // end finally block
    
    return ( nReturn );

} //end of main()

//建立会话
//
//abstract: open a WinSNMP session
//input :   PSNMP_MGR_SESSION pSession
//output:   TRUE if successful, FALSE if not.
//        
BOOL    OpenWinSNMPSession ( PSNMP_MGR_SESSION pSession )
{

    smiOCTETS smiCommunity;

    if ( pSession == NULL )
        return ( FALSE );
    //建立会话
    // create a remote session
    pSession->hSnmpSession = SnmpOpen( pSession->hWnd, WM_SNMP_INCOMING );

    if ( SNMP_FAILURE( pSession->hSnmpSession ) )
        return ( FALSE );

    if ( gVars.pAgentStrAddr != NULL )
    {
        //创建实体
        // create a remote agent entity
        pSession->hAgentEntity = SnmpStrToEntity( pSession->hSnmpSession, 
                                            inet_ntoa( gVars.agentSockAddr.sin_addr ) );     

        if ( SNMP_FAILURE( pSession->hAgentEntity ) )
            return ( FALSE );
        //设置实体的超时时间和重传次数
        // attach timeout specified with agent
        SnmpSetTimeout( pSession->hAgentEntity, gVars.nTimeOut / 10 );
        
        // attach retries specified with agent
        SnmpSetRetry( pSession->hAgentEntity, gVars.nRetries );

        // create local manager entity
        pSession->hManagerEntity = SnmpStrToEntity(
                                     pSession->hSnmpSession,
                                     DEFAULT_ADDRESS_IP );
        if ( SNMP_FAILURE( pSession->hManagerEntity ) )
            return ( FALSE );

        // attach timeout specified with manager
        SnmpSetTimeout( pSession->hManagerEntity, gVars.nTimeOut / 10 );

        // attach retries specified with manager
        SnmpSetRetry( pSession->hManagerEntity, gVars.nRetries );  

    } // end of if ( pAgentStrAddr )

        // validate pointer
    if ( gVars.pAgentCommunity != NULL) 
    {

        // transfer community string
        smiCommunity.ptr = (smiLPBYTE)gVars.pAgentCommunity;
        smiCommunity.len = gVars.pAgentCommunity ? lstrlen( gVars.pAgentCommunity) : 0;
        //创建上下文句柄
        // obtain context from community string
        pSession->hViewContext = SnmpStrToContext(
                                     pSession->hSnmpSession,
                                     &smiCommunity
                                    );

        // validate context handle
        if ( SNMP_FAILURE( pSession->hViewContext) ) 
            return ( FALSE );

    }

    // success
    return (TRUE);
  
}  //end of OpenWinSNMP Session


//
// abstarct:   close a WinSNMP session
// input :     pointer to a SNMP_MGR_SESSION
// output:     TRUE if successful, FALSE if not.    
//
BOOL    CloseWinSNMPSession ( PSNMP_MGR_SESSION pSession )
{

    BOOL fOk = TRUE;
    SNMPAPI_STATUS status;

    // validate session ptr
    if ( pSession == NULL )
        return FALSE;

    // check if window opened
    if ( pSession->hWnd != (HWND)NULL ) 
    {
        // destroy notification window
        fOk = DestroyNotificationWindow( pSession );
    }
    //释放资源
    // close view context
    if ( pSession->hViewContext  != (HSNMP_CONTEXT) NULL)
    {   //释放资源
        SnmpFreeContext( pSession->hViewContext );
    }

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

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

        // validate status
        if ( status == SNMPAPI_FAILURE ) 
        {
            // failure
            fOk = FALSE;
        }

        // re-initialize
        pSession->hAgentEntity = (HSNMP_ENTITY)NULL;
    }

    // check if manager entity allocated
    if ( pSession->hManagerEntity != (HSNMP_ENTITY)NULL ) 
    {

        // close the entity handle
        status = SnmpFreeEntity( pSession->hManagerEntity );

        // validate status
        if ( status == SNMPAPI_FAILURE ) 
        {
    
            // failure
            fOk = FALSE;
        }

        // re-initialize
        pSession->hManagerEntity = (HSNMP_ENTITY)NULL;
    }

   
    // check if session allocated
    if ( pSession->hSnmpSession != (HSNMP_SESSION)NULL ) 
    {

        // close the winsnmp session
        status = SnmpClose( pSession->hSnmpSession );

        // validate status
        if ( status == SNMPAPI_FAILURE )
        {
            // failure
            fOk = FALSE;
        }

        // re-initialize
        pSession->hSnmpSession = (HSNMP_SESSION)NULL;
    }

    return fOk;

} // end of CloseWinSNMPSession



//
// abstarct: create a notification window, which will receive WinSnmp messages.
//           The window will remain hidden.
//
// input:    pointer to PSNMP_MGR_SESSION
// 
// output:
// TRUE     if successful in creating the window
// FALSE    if not successful in creating the window handle.
//
BOOL    CreateNotificationWindow( PSNMP_MGR_SESSION pSession )
{

    BOOL    fOk;
    WNDCLASS wc;

    if ( pSession == NULL )
    {    
        return FALSE;
    }

    // initialize notification window class
    wc.lpfnWndProc   = (WNDPROC)NotificationWndProc;
    wc.lpszClassName = NOTIFICATION_CLASS;
    wc.lpszMenuName  = NULL;
    wc.hInstance     = gVars.g_hInst;
    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) 
    {
        PrintDbgMessage( "snmputil: RegisterClass returned %d.\n", GetLastError() );
        return (FALSE);
    }
    // create notification window
    pSession->hWnd = CreateWindow(
                      NOTIFICATION_CLASS,
                      "SNMP Util Class",                // pointer to window name
                      WS_OVERLAPPEDWINDOW,              // 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
                      gVars.g_hInst,                    // handle to application instance
                      NULL                              // pointer to window-creation data
                    );

    // validate window handle
    if ( pSession->hWnd != NULL ) 
    {
        // store pointer to session in window
      ////陈 SetWindowLongPtr( pSession->hWnd, 0, (INT_PTR)pSession );

        // success
        fOk = TRUE;
    } 
    else 
    {     
        // failure
        fOk = FALSE;
    }

    return fOk;
    
} // end of CreateNotificationWindow