winextdll.c

开发snmp的开发包有两个开放的SNMP开发库

        winExtensionAgent[winExtensionAgent_num].my_handler = netsnmp_create_handler_registration("winExtDLL",
            var_winExtDLL,
            name,
            length,
            HANDLER_CAN_RWRITE);
        
        if (!winExtensionAgent[winExtensionAgent_num].my_handler) {
          snmp_log(LOG_ERR,
              "malloc failed registering handler for winExtDLL");
          DEBUGMSGTL(("winExtDLL", "malloc failed registering handler for winExtDLL"));
          return (-1);
        }
        else {
          DEBUGMSGTL(("winExtDLL", "handler registered\n"));
        }
        
        // Register handler with Net-SNMP
        netsnmp_register_handler(winExtensionAgent[winExtensionAgent_num].my_handler);

        winExtensionAgent_num++;
      } 
    }
    winExtensionAgent_num++;
  }


  winExtensionAgent_index = winExtensionAgent_num-1;             // Array index
  DEBUGMSGTL(("winExtDLL", "winExtensionAgent_index: %d\n",winExtensionAgent_index));

  /* Reverse sort array of winExtensionAgents */
  i = sizeof(winExtensionAgent) / sizeof(winExtensionAgents);
  //DEBUGMSGTL(("winExtDLL", "Sorting...\n"));
  for (iter=0; iter < i-1; iter++) {
    for (indx=0; indx < i-1; indx++) {
      if (snmp_oidtree_compare(winExtensionAgent[indx].name, winExtensionAgent[indx].name_length,
            winExtensionAgent[indx+1].name, winExtensionAgent[indx+1].name_length) < 0) {
        winExtensionAgent_temp = winExtensionAgent[indx];
        winExtensionAgent[indx] = winExtensionAgent[indx+1];
        winExtensionAgent[indx+1] = winExtensionAgent_temp;
      }
    }
  }
  DEBUGMSGTL(("winExtDLL", "Dumping sorted Windows extension OIDs\n"));
  for (i=0; winExtensionAgent[i].xSnmpExtensionInit; i++) {
    DEBUGMSGTL(("winExtDLL", "DLL name: %s, view: ",winExtensionAgent[i].dll_name));
    DEBUGMSGOID(("winExtDLL", winExtensionAgent[i].name, winExtensionAgent[i].name_length));
    DEBUGMSG(("winExtDLL", "\n"));
  }

  DEBUGMSGTL(("winExtDLL", "Number of subagentTrapEvents: %d\n",subagentTrapEvents_index));

  if (subagentTrapEvents_index) {
    
    DEBUGMSGTL(("winExtDLL", "Setting alarm check for subagent trap events every 5 seconds\n"));
    snmp_alarm_register(5,      /* seconds */
        SA_REPEAT,              /* repeat (every x seconds). */
        subagentTrapCheck,      /* our callback */
        NULL                    /* no callback data needed */
        );    
  }
}

int
var_winExtDLL(netsnmp_mib_handler *handler,
              netsnmp_handler_registration *reginfo,
              netsnmp_agent_request_info *reqinfo,
              netsnmp_request_info *requests)
{

    netsnmp_request_info *request = requests;
    netsnmp_variable_list *var;
    oid             oid_requested[MAX_OID_LEN];
    size_t          oid_requested_length;
    
    static char     ret_szbuf_temp[SZBUF_MAX];          // Holder for return strings
    static oid      ret_oid[MAX_OID_LEN];               // Holder for return OIDs
    static size_t   ret_oid_length = 0;                 // Holder for return OIDs
    static long     ret_long;                           // Holder for all other returns

    static char     set_szbuf_temp[SZBUF_MAX];          // Holder for set strings    
    static oid      set_oid[MAX_OID_LEN];               // Holder for set OIDs
    static size_t   set_oid_length = 0;                 // Holder for set OIDs
    oid             *temp_oid;
    size_t          temp_oid_length;
    
    static int      temp;
    static u_long   accesses = 7;
    u_char          netsnmp_ASN_type;
    u_char          windows_ASN_type;

    char          *stringtemp;

    // WinSNMP variables:
    BOOL result;   
    SnmpVarBind *mySnmpVarBind;
    AsnInteger32 pErrorStatus;
    AsnInteger32 pErrorIndex;
    SnmpVarBindList pVarBindList;  
    int i=0;
    int j=0;

    DWORD (WINAPI *xSnmpExtensionQuery)(BYTE, SnmpVarBindList* ,AsnInteger32* ,AsnInteger32*);
    DWORD (WINAPI *xSnmpExtensionQueryEx)(DWORD, DWORD, SnmpVarBindList*, AsnOctetString*, AsnInteger32*, AsnInteger32*);
    DWORD (WINAPI *next_xSnmpExtensionQuery)(BYTE, SnmpVarBindList* ,AsnInteger32* ,AsnInteger32*);
    DWORD (WINAPI *next_xSnmpExtensionQueryEx)(DWORD, DWORD, SnmpVarBindList*, AsnOctetString*, AsnInteger32*, AsnInteger32*);
    AsnObjectIdentifier winExtensionAgent_pSupportedView;               // Support view of this extension agent
    oid winExtensionAgent_name[MAX_OID_LEN];                            // Support view of this extension agent
    size_t winExtensionAgent_name_length;                               // Support view of this extension agent

    int match_winExtensionAgent_index = -1;

    DEBUGMSGTL(("winExtDLL", "-----------------------------------------\n"));
    DEBUGMSGTL(("winExtDLL", "var_winExtDLL handler starting, mode = %d\n",
                reqinfo->mode));
    
    switch (reqinfo->mode) {
    case MODE_GET:
    case MODE_GETNEXT:

      if (reqinfo->mode == MODE_GET)
        DEBUGMSGTL(("winExtDLL", "GET requested\n"));
      else if (reqinfo->mode == MODE_GETNEXT)
        DEBUGMSGTL(("winExtDLL", "GETNEXT requested\n"));
      
      for (request = requests; request; request=request->next) {
        
        var = request->requestvb;

        // Make copy of requested OID
        for (i = 0; i < (var->name_length > MAX_OID_LEN? MAX_OID_LEN: var->name_length); i++) {
          oid_requested[i] = var->name[i];
        }
        oid_requested_length = i;
        
        DEBUGMSGTL(("winExtDLL", "Requested: "));
        DEBUGMSGOID(("winExtDLL", oid_requested, oid_requested_length));
        DEBUGMSG(("winExtDLL", "\n"));       

        DEBUGMSGTL(("winExtDLL", "Var type requested: %d\n",var->type));

        /* Loop through all the winExtensionAgent's looking for a matching handler */
        xSnmpExtensionQuery = NULL;
        xSnmpExtensionQueryEx = NULL;
        next_xSnmpExtensionQuery = NULL;
        next_xSnmpExtensionQueryEx = NULL;

        DEBUGMSGTL(("winExtDLL", "Looping through all the winExtensionAgent's looking for a matching handler (exact).\n"));
        // Search starting with lowest so a walk of .1.3 starts with the lowest extension
        for (i = winExtensionAgent_index; winExtensionAgent[i].xSnmpExtensionInit && i >= 0; i--) {          

          /*DEBUGMSGTL(("winExtDLL", "Comparing: "));
          DEBUGMSGOID(("winExtDLL", var->name, var->name_length));
          DEBUGMSG(("winExtDLL", "\n"));       

          DEBUGMSGTL(("winExtDLL", "to:        "));
          DEBUGMSGOID(("winExtDLL", winExtensionAgent[i].name, winExtensionAgent[i].name_length));
          DEBUGMSG(("winExtDLL", "\n"));*/

          if (snmp_oidtree_compare(var->name, var->name_length, winExtensionAgent[i].name, 
                winExtensionAgent[i].name_length) == 0) {

            DEBUGMSGTL(("winExtDLL", "Found exact match: "));
            DEBUGMSGOID(("winExtDLL", winExtensionAgent[i].name, winExtensionAgent[i].name_length));
            DEBUGMSG(("winExtDLL", "\n"));
            match_winExtensionAgent_index = i;
            //DEBUGMSGTL(("winExtDLL", "Index: %d\n",match_winExtensionAgent_index));
            break;
          }
        }

        if (match_winExtensionAgent_index == -1) {
          DEBUGMSGTL(("winExtDLL", "Looping through all the winExtensionAgent's looking for a matching handler (next best).\n"));
          for (i=0; winExtensionAgent[i].xSnmpExtensionInit && i < MAX_WINEXT_DLLS; i++) {
            
            /*DEBUGMSGTL(("winExtDLL", "Comparing: "));
            DEBUGMSGOID(("winExtDLL", var->name, var->name_length));
            DEBUGMSG(("winExtDLL", "\n"));       
            
            DEBUGMSGTL(("winExtDLL", "to:        "));
            DEBUGMSGOID(("winExtDLL", winExtensionAgent[i].name, winExtensionAgent[i].name_length));
            DEBUGMSG(("winExtDLL", "\n"));       
            DEBUGMSGTL(("winExtDLL", "and:       "));
            DEBUGMSGOID(("winExtDLL", winExtensionAgent[i+1].name, winExtensionAgent[i+1].name_length));
            DEBUGMSG(("winExtDLL", "\n"));       */

            if (snmp_oidtree_compare(var->name, var->name_length, winExtensionAgent[i].name, 
                  winExtensionAgent[i].name_length) <= 0 &&
                snmp_oidtree_compare(var->name, var->name_length, winExtensionAgent[i+1].name, 
                  winExtensionAgent[i+1].name_length) >= 0                      // FIXME:  Checking past the last extension?
               ) {
              DEBUGMSGTL(("winExtDLL", "Found best match: "));
              DEBUGMSGOID(("winExtDLL", winExtensionAgent[i].name, winExtensionAgent[i].name_length));
              DEBUGMSG(("winExtDLL", "\n"));
              match_winExtensionAgent_index = i;
              //DEBUGMSGTL(("winExtDLL", "Index: %d\n",match_winExtensionAgent_index));
              break;
            }
          }
        }

        //DEBUGMSG(("winExtDLL", "Index: %d\n",match_winExtensionAgent_index));

        if (match_winExtensionAgent_index == -1) {
          DEBUGMSGTL(("winExtDLL","Could not find a handler for the requested OID.  This should never happen!!\n"));
          return SNMP_ERR_GENERR;
        }

        // Make copy of current extension's OID
        for (j = 0; j < (winExtensionAgent[i].name_length > MAX_OID_LEN? MAX_OID_LEN: winExtensionAgent[i].name_length); j++) {
          winExtensionAgent_name[j] = winExtensionAgent[i].name[j];
        }
        winExtensionAgent_name_length = j;

        xSnmpExtensionQuery = winExtensionAgent[i].xSnmpExtensionQuery;
        xSnmpExtensionQueryEx = winExtensionAgent[i].xSnmpExtensionQueryEx;
        SnmpUtilOidCpy(&winExtensionAgent_pSupportedView, &winExtensionAgent[i].pSupportedView);

        if (! (xSnmpExtensionQuery || xSnmpExtensionQueryEx)) {
          if (reqinfo->mode == MODE_GET) {
            DEBUGMSGTL(("winExtDLL","Could not find a handler for the requested OID.  This should never happen!!\n"));
            return SNMP_ERR_GENERR;
          }
          else {
            DEBUGMSGTL(("winExtDLL","Could not find a handler for the requested OID.  Returning SNMP_ERR_NOSUCHNAME.\n"));
            return SNMP_ERR_NOSUCHNAME;
          }
        }
        
        // Query
        pVarBindList.list = (SnmpVarBind *) SnmpUtilMemAlloc(sizeof (SnmpVarBind));
        if (pVarBindList.list) {

          // Convert OID from Net-SNMP to Windows         
         
          pVarBindList.list->name.ids = (UINT *) SnmpUtilMemAlloc(sizeof (UINT) *var->name_length);
          
          if (pVarBindList.list->name.ids) {
            // Actual copy
            
            for (i = 0; i < var->name_length; i++) {
              pVarBindList.list->name.ids[i] = (UINT)var->name[i];
            }
            pVarBindList.list->name.idLength = i;
            
            DEBUGMSGTL(("winExtDLL", "Windows OID: "));
            DEBUGMSGWINOID(("winExtDLL", pVarBindList.list));
            DEBUGMSG(("winExtDLL", "\n"));
            
          }
          else {
            DEBUGMSGTL(("winExtDLL", "\nyCould not allocate memory for Windows SNMP varbind.\n"));
            return (0);
          }

          //pVarBindList.list = pVarBindList.list;

          pVarBindList.len = 1;          
	}
        else {
          DEBUGMSGTL(("winExtDLL", "Could not allocate memory for Windows SNMP varbind list.\n"));
          return (0);
        }        
		
        if (reqinfo->mode == MODE_GET) {
          DEBUGMSGTL(("winExtDLL", "win: MODE_GET\n"));
          if (xSnmpExtensionQueryEx) {
            DEBUGMSGTL(("winExtDLL", "Calling xSnmpExtensionQueryEx\n"));
            result = xSnmpExtensionQueryEx(SNMP_PDU_GET, 1, &pVarBindList, NULL, &pErrorStatus, &pErrorIndex);
          }
          else { 
            DEBUGMSGTL(("winExtDLL", "Calling xSnmpExtensionQuery\n"));
            result = xSnmpExtensionQuery(SNMP_PDU_GET, &pVarBindList, &pErrorStatus, &pErrorIndex);
          } 
        }
        else if (reqinfo->mode == MODE_GETNEXT) {
          DEBUGMSGTL(("winExtDLL", "win: MODE_GETNEXT -\n"));
          if (xSnmpExtensionQueryEx) {
            DEBUGMSGTL(("winExtDLL", "Calling xSnmpExtensionQueryEx\n"));
            result = xSnmpExtensionQueryEx(SNMP_PDU_GETNEXT, 1, &pVarBindList, NULL, &pErrorStatus, &pErrorIndex);
          }
          else { 
            DEBUGMSGTL(("winExtDLL", "Calling xSnmpExtensionQuery\n"));
            result = xSnmpExtensionQuery(SNMP_PDU_GETNEXT, &pVarBindList, &pErrorStatus, &pErrorIndex);
          } 

          DEBUGMSGTL(("winExtDLL", "Windows OID returned from xSnmpExtensionQuery(Ex): "));
          DEBUGMSGWINOID(("winExtDLL", pVarBindList.list));
          DEBUGMSG(("winExtDLL", "\n"));

          // Convert OID from Windows to Net-SNMP so Net-SNMP has the new 'next' OID
          // FIXME:  Do we need to realloc var->name or is is MAX_OID_LEN?
          for (i = 0; i < (pVarBindList.list->name.idLength > MAX_OID_LEN?MAX_OID_LEN:pVarBindList.list->name.idLength); i++) {
            var->name[i] = (oid)pVarBindList.list->name.ids[i];
          }
          var->name_length = i;

          DEBUGMSGTL(("winExtDLL", "Comparing: "));
          DEBUGMSGOID(("winExtDLL", var->name, var->name_length));
          DEBUGMSG(("winExtDLL", "\n"));       

          DEBUGMSGTL(("winExtDLL", "to:        "));
          DEBUGMSGOID(("winExtDLL", winExtensionAgent_name, winExtensionAgent_name_length));
          DEBUGMSG(("winExtDLL", "\n"));       
          

          // If the OID we got back is less than or equal to what we requested, increment the current supported view
          // and send it back instead.
          if (snmp_oid_compare(var->name, var->name_length, oid_requested, oid_requested_length) <= 0) {
            DEBUGMSGTL(("winExtDLL", "xSnmpExtensionQuery(Ex) returned an OID less than or equal to what we requested\n"));
            DEBUGMSGTL(("winExtDLL", " Setting return OID to be equal to current supported view, plus one\n"));

            // Set var->name to be equal to current supported view, plus one
            for (i = 0; i < (winExtensionAgent_name_length > MAX_OID_LEN? MAX_OID_LEN: winExtensionAgent_name_length); i++) {
              var->name[i] = winExtensionAgent_name[i];
            }
            var->name_length = i;
            var->name[i-1]++;

            //return SNMP_ERR_NOSUCHNAME;
            
          }