winextdll.c

开发snmp的开发包有两个开放的SNMP开发库

/*
 *  winExtDLL Net-SNMP extension
 *  (c) 2006 Alex Burger
 *
 *  Created 9/9/06
 *
 * Purpose:  To load Windows SNMP Service extension DLLs provided with Windows
 *           (such as hostmib.dll).  This allows Net-SNMP to be a replacement 
 *           for the Windows SNMP service.
 *
 * Notes:    This extension requires the PSDK including the Snmp.h header file.
 *           Including Snmp.h will conflict with existing Net-SNMP defines for
 *           ASN_OCTETSTRING etc.  To resolve this, create a copy of Snmp.h in
 *           the PSDK include/ folder called Snmp-winExtDLL.h and change all
 *           occurances of ASN_ to MS_ASN_
 *
 *           This extension requires that the Windows SNMP Service is installed
 *           but set to disabled.  This is required so that the extension DLLs 
 *           are available for loading, and also because this extension and the 
 *           existing Windows extensions use the Windows SNMP API from snmpapi.dll.
 *
 *           This extension is NOT for dynamically loading Net-SNMP extensions.
 */

#include <windows.h>
#include <cstdio>
#include <Snmp-winExtDLL.h>                  // Modified Windows SDK snmp.h.  See Notes above
#include <mgmtapi.h>
#include <string.h>

/*
 * include important headers 
 */
#include <net-snmp/net-snmp-config.h>
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif

/*
 * needed by util_funcs.h 
 */
#if TIME_WITH_SYS_TIME
# ifdef WIN32
#  include <sys/timeb.h>
# else
#  include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif

#if HAVE_WINSOCK_H
#include <winsock.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>

#include "util_funcs.h"

#include "winExtDLL.h"

#define SZBUF_MAX               1024
#define SZBUF_DLLNAME_MAX       254
#define MAX_WINEXT_DLLS         100
#define MAX_KEY_LENGTH          255
#define MAX_VALUE_NAME          16383
#define MAX_WINEXT_TRAP_EVENTS  100

#define DEBUGMSGWINOID(x)     do {if (_DBG_IF_) {__DBGMSGWINOID(x);} }while(0)
#define __DBGMSGWINOID(x)     debugmsg_win_oid x
void debugmsg_win_oid(const char *token, const AsnObjectIdentifier * theoid);

/* Structure to hold name, pointers to functions and MIB tree supported by
 * each Windows SNMP Extension DLL */
typedef struct {
  char          dll_name[SZBUF_DLLNAME_MAX];
  DWORD (WINAPI *xSnmpExtensionInit)(DWORD, HANDLE*, AsnObjectIdentifier*);
  DWORD (WINAPI *xSnmpExtensionInitEx)(AsnObjectIdentifier*);
  DWORD (WINAPI *xSnmpExtensionQuery)(BYTE, SnmpVarBindList* ,AsnInteger32* ,AsnInteger32*);
  DWORD (WINAPI *xSnmpExtensionQueryEx)(DWORD, DWORD, SnmpVarBindList*, AsnOctetString*, AsnInteger32*, AsnInteger32*);
  BOOL  (WINAPI *xSnmpExtensionTrap)( AsnObjectIdentifier *, AsnInteger *, AsnInteger *, AsnTimeticks *, SnmpVarBindList * );
  HANDLE        *subagentTrapEvent;
  netsnmp_handler_registration *my_handler;
  oid           name[MAX_OID_LEN];              //   pSupportedView in Net-SNMP format
  size_t        name_length;
  AsnObjectIdentifier pSupportedView;
} winExtensionAgents;

winExtensionAgents winExtensionAgent[MAX_WINEXT_DLLS];
winExtensionAgents winExtensionAgent_temp;      /* For sorting */
int winExtensionAgent_index = 0;

char *extDLLs[MAX_WINEXT_DLLS];
int extDLLs_index = 0;

HANDLE *subagentTrapEvents[MAX_WINEXT_TRAP_EVENTS];
int subagentTrapEvents_index = 0;

void winExtDLL_free_config_winExtDLL(void);

void read_ExtensionAgents_list();
void read_ExtensionAgents_list2(const TCHAR *);

void subagentTrapCheck();

void send_trap(
    AsnObjectIdentifier *, 
    AsnInteger *, 
    AsnInteger *, 
    AsnTimeticks *,    
    SnmpVarBindList *);

void init_winExtDLL(void)
{
  // Windows SNMP
  DWORD dwUptimeReference = 0;
  HANDLE subagentTrapEvent;
  AsnObjectIdentifier pSupportedView;
  BOOL result;
  HANDLE hThread;
  DWORD IDThread;

  char dll_name[SZBUF_DLLNAME_MAX];
  DWORD (WINAPI *xSnmpExtensionInit)(DWORD, HANDLE*, AsnObjectIdentifier*);
  DWORD (WINAPI *xSnmpExtensionInitEx)(AsnObjectIdentifier*);
  DWORD (WINAPI *xSnmpExtensionQuery)(BYTE, SnmpVarBindList* ,AsnInteger32* ,AsnInteger32*);
  DWORD (WINAPI *xSnmpExtensionQueryEx)(DWORD, DWORD, SnmpVarBindList*, AsnOctetString*, AsnInteger32*, AsnInteger32*);
  BOOL  (WINAPI *xSnmpExtensionTrap)( AsnObjectIdentifier *, AsnInteger *, AsnInteger *, AsnTimeticks *, SnmpVarBindList * );

  // Net-SNMP
  oid name[MAX_OID_LEN];
  size_t length = 0;
  int i;
  int DLLnum = 0;
  int winExtensionAgent_num = 0;
  
  int iter, indx;
  
  netsnmp_handler_registration *my_handler;

  HANDLE hInst = NULL;

  DEBUGMSGTL(("winExtDLL", "init_winExtDLL called\n"));

  read_ExtensionAgents_list();  
  
  DEBUGMSGTL(("winExtDLL", "winExtDLL enabled.\n"));   
  
  DEBUGMSGTL(("winExtDLL", "Size of winExtensionAgent: %d\n",sizeof(winExtensionAgent) / sizeof(winExtensionAgents)));

  for(i=0; i <= sizeof(winExtensionAgent) / sizeof(winExtensionAgents); i++) {
    winExtensionAgent[0].xSnmpExtensionInit = NULL;
    winExtensionAgent[0].xSnmpExtensionInitEx = NULL;
  }

  /* Load all the DLLs */
  for (DLLnum = 0; DLLnum <= extDLLs_index; DLLnum++) {

    if (! (extDLLs[DLLnum]))
      continue;

    DEBUGMSGTL(("winExtDLL", "-----------------------------------------\n"));
    DEBUGMSGTL(("winExtDLL", "DLL to load: %s, DLL number: %d, winExtensionAgent_num: %d\n", extDLLs[DLLnum], DLLnum,
          winExtensionAgent_num));
    DEBUGMSGTL(("winExtDLL", "Size of DLL to load: %d\n", strlen(extDLLs[DLLnum])));
    
    hInst = LoadLibrary(extDLLs[DLLnum]);
    
    if (hInst == NULL)
    {
      DEBUGMSGTL(("winExtDLL","Could not load Windows extension DLL %s.\n", extDLLs[DLLnum]));
      snmp_log(LOG_ERR,
          "Could not load Windows extension DLL: %s.\n", extDLLs[DLLnum]);
      continue;
    }
    else {
      DEBUGMSGTL(("winExtDLL","DLL loaded.\n"));
    }

    // Create local copy of DLL name and functions
    strncpy(dll_name, extDLLs[DLLnum], SZBUF_DLLNAME_MAX-1);
    xSnmpExtensionInit = (DWORD (WINAPI *)(DWORD, HANDLE*, AsnObjectIdentifier*)) 
      GetProcAddress ((HMODULE) hInst, "SnmpExtensionInit");
    xSnmpExtensionInitEx = (DWORD (WINAPI *)(AsnObjectIdentifier*)) 
      GetProcAddress ((HMODULE) hInst, "SnmpExtensionInitEx");
    xSnmpExtensionQuery = (DWORD (WINAPI *)(BYTE, SnmpVarBindList* ,AsnInteger32* ,AsnInteger32*)) 
      GetProcAddress ((HMODULE) hInst, "SnmpExtensionQuery");
    xSnmpExtensionQueryEx = (DWORD (WINAPI *)(DWORD, DWORD, SnmpVarBindList*, AsnOctetString*, AsnInteger32*, AsnInteger32*))
      GetProcAddress ((HMODULE) hInst, "SnmpExtensionQueryEx");
    xSnmpExtensionTrap = (BOOL  (WINAPI *)(AsnObjectIdentifier *, AsnInteger *, AsnInteger *, AsnTimeticks *, SnmpVarBindList * ))
      GetProcAddress ((HMODULE) hInst, "SnmpExtensionTrap");

    if (xSnmpExtensionQuery)
      DEBUGMSGTL(("winExtDLL", "xSnmpExtensionQuery found\n"));
    if (xSnmpExtensionQueryEx)
      DEBUGMSGTL(("winExtDLL", "xSnmpExtensionQueryEx found\n"));
    if (xSnmpExtensionQuery)
      DEBUGMSGTL(("winExtDLL", "xSnmpExtensionTrap found\n"));

    // Store DLL name and functions in winExtensionAgent array
    strncpy(winExtensionAgent[winExtensionAgent_num].dll_name, dll_name, SZBUF_DLLNAME_MAX-1);
    winExtensionAgent[winExtensionAgent_num].xSnmpExtensionInit = xSnmpExtensionInit;
    winExtensionAgent[winExtensionAgent_num].xSnmpExtensionInitEx = xSnmpExtensionInitEx;
    winExtensionAgent[winExtensionAgent_num].xSnmpExtensionQuery = xSnmpExtensionQuery;
    winExtensionAgent[winExtensionAgent_num].xSnmpExtensionQueryEx = xSnmpExtensionQueryEx;
    winExtensionAgent[winExtensionAgent_num].xSnmpExtensionTrap = xSnmpExtensionTrap;

    // Init and get first supported view from Windows SNMP extension DLL  
    result = xSnmpExtensionInit(dwUptimeReference, &subagentTrapEvent, &pSupportedView);

    DEBUGMSGTL(("winExtDLL", "Supported view: "));
    DEBUGMSGWINOID(("winExtDLL", &pSupportedView));
    DEBUGMSG(("winExtDLL", "\n"));

    // Store the subagent's trap handler, even if it's NULL
    winExtensionAgent[winExtensionAgent_num].subagentTrapEvent = subagentTrapEvent;

    // Store the subagent's trap handler in a global array for use by waitformultipleobjects()
    if (subagentTrapEvent) {
      DEBUGMSGTL(("winExtDLL", "Trap handler defined.  Storing...\n"));
      subagentTrapEvents[subagentTrapEvents_index] = subagentTrapEvent;
      subagentTrapEvents_index++;
    }

    // Convert OID from Windows 'supported view' to Net-SNMP
    for (i = 0; i < (pSupportedView.idLength > MAX_OID_LEN?MAX_OID_LEN:pSupportedView.idLength); i++) {
      name[i] = (oid)pSupportedView.ids[i];
    }
    length = i;

    // Store supported view in Net-SNMP format
    memcpy(winExtensionAgent[winExtensionAgent_num].name, name, sizeof(name));
    winExtensionAgent[winExtensionAgent_num].name_length = length;
 
    DEBUGMSGTL(("winExtDLL", "Windows OID converted to Net-SNMP: "));
    DEBUGMSGOID(("winExtDLL", name, length));
    DEBUGMSG(("winExtDLL", "\n"));

    // Store supported view in Windows format
    SnmpUtilOidCpy(&winExtensionAgent[winExtensionAgent_num].pSupportedView,&pSupportedView);

    // Create handler registration
    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);

    // Check for additional supported views and register them with the same handler
    if (winExtensionAgent[winExtensionAgent_num].xSnmpExtensionInitEx) {
      DEBUGMSGTL(("winExtDLL", "xSnmpExtensionInitEx found\n"));

      winExtensionAgent_num++;

      while (1) { // Loop looking for more supported views
        // Store DLL name and functions in winExtensionAgent array  
        strncpy(winExtensionAgent[winExtensionAgent_num].dll_name, dll_name, SZBUF_DLLNAME_MAX-1);
        winExtensionAgent[winExtensionAgent_num].xSnmpExtensionInit = xSnmpExtensionInit;
        winExtensionAgent[winExtensionAgent_num].xSnmpExtensionInitEx = xSnmpExtensionInitEx;
        winExtensionAgent[winExtensionAgent_num].xSnmpExtensionQuery = xSnmpExtensionQuery;
        winExtensionAgent[winExtensionAgent_num].xSnmpExtensionQueryEx = xSnmpExtensionQueryEx;
        winExtensionAgent[winExtensionAgent_num].xSnmpExtensionTrap = xSnmpExtensionTrap;     
        winExtensionAgent[winExtensionAgent_num].subagentTrapEvent = NULL;
        // Get extra supported view
        result = xSnmpExtensionInitEx(&pSupportedView);

        if (! (result)) {
          winExtensionAgent_num--;
          break;
        }

        DEBUGMSGTL(("winExtDLL", "result of xSnmpExtensionInitEx: %d\n",result));
      
        DEBUGMSGTL(("winExtDLL", "Supported view: "));
        DEBUGMSGWINOID(("winExtDLL", &pSupportedView));
        DEBUGMSG(("winExtDLL", "\n"));
        
        // Convert OID from Windows 'supported view' to Net-SNMP
        for (i = 0; i < (pSupportedView.idLength > MAX_OID_LEN?MAX_OID_LEN:pSupportedView.idLength); i++) {
          name[i] = (oid)pSupportedView.ids[i];
        }
        length = i;
  
        // Store supported view in Net-SNMP format
        memcpy(winExtensionAgent[winExtensionAgent_num].name, name, sizeof(name));
        winExtensionAgent[winExtensionAgent_num].name_length = length;

        DEBUGMSGTL(("winExtDLL", "Windows OID converted to Net-SNMP: "));
        DEBUGMSGOID(("winExtDLL", name, length));
        DEBUGMSG(("winExtDLL", "\n"));
  
        // Store supported view in Windows format
        SnmpUtilOidCpy(&winExtensionAgent[winExtensionAgent_num].pSupportedView,&pSupportedView);
  
        // Create handler registration