Source code of Windows XP (NT5)
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//+----------------------------------------------------------------------------
//
// File: wsock.cpp
//
// Module: CMDIAL32.DLL
//
// Synopsis: This module contains the winsock related CM code.
//
// Copyright (c) 1996-1999 Microsoft Corporation
//
// Author: henryt created 03/??/98
// quintinb created Header 08/16/99
//
//+----------------------------------------------------------------------------
#include "cmmaster.h"
#include "winsock.h"
#include "tunl_str.h"
///////////////////////////////////////////////////////////////////////////////////
// define's
///////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////
// typedef's
///////////////////////////////////////////////////////////////////////////////////
typedef int (PASCAL FAR *PFN_WSAStartup)(WORD, LPWSADATA);
typedef int (PASCAL FAR *PFN_WSACleanup)(void);
typedef struct hostent FAR * (PASCAL FAR *PFN_gethostbyname)(const char FAR * name);
///////////////////////////////////////////////////////////////////////////////////
// func prototypes
///////////////////////////////////////////////////////////////////////////////////
BOOL InvokeGetHostByName(
ArgsStruct *pArgs
);
BOOL BuildDnsTunnelList(
ArgsStruct *pArgs,
struct hostent *pHe
);
BOOL BuildRandomTunnelIndex(
ArgsStruct *pArgs,
DWORD dwCount
);
///////////////////////////////////////////////////////////////////////////////////
// Implementation
///////////////////////////////////////////////////////////////////////////////////
//+---------------------------------------------------------------------------
//
// Function: TryAnotherTunnelDnsAddress
//
// Synopsis: see if there's another dns address associated with the current
// tunnel name. if so, set that address in primary or extended
// tunnel ip properly.
//
// Arguments: pArgs ptr to ArgsStruct
//
// Returns: TRUE if SUCCESS
// FALSE otherwise.
//
//----------------------------------------------------------------------------
BOOL TryAnotherTunnelDnsAddress(
ArgsStruct *pArgs
)
{
MYDBGASSERT(pArgs);
//
// RAS does all this for us on NT5, so bail out now.
//
if (NULL == pArgs || OS_NT5)
{
return FALSE;
}
//
// if the list of tunnel ip addrs is empty, let's resolve the dns name
// and see if there are other addrs behind the dns name.
//
if (!pArgs->pucDnsTunnelIpAddr_list)
{
if (!InvokeGetHostByName(pArgs))
{
return FALSE;
}
}
MYDBGASSERT(pArgs->pucDnsTunnelIpAddr_list);
if (pArgs->uiCurrentDnsTunnelAddr == pArgs->dwDnsTunnelAddrCount - 1)
{
//
// we've run out of addrs in the list.
//
//
// we need to destroy the list
//
CmFree(pArgs->pucDnsTunnelIpAddr_list);
pArgs->pucDnsTunnelIpAddr_list = NULL;
CmFree(pArgs->rgwRandomDnsIndex);
pArgs->rgwRandomDnsIndex = NULL;
pArgs->uiCurrentDnsTunnelAddr = 0;
pArgs->dwDnsTunnelAddrCount = 0;
//
// If we're currently using the primary tunnel server, we need to
// restore it since we overwrote it.
//
LPTSTR pszTunnelIp = pArgs->piniBothNonFav->GPPS(c_pszCmSection, c_pszCmEntryTunnelAddress);
if (lstrlenU(pszTunnelIp) > RAS_MaxPhoneNumber)
{
pszTunnelIp[0] = TEXT('\0');
}
pArgs->SetPrimaryTunnel(pszTunnelIp);
CmFree(pszTunnelIp);
return FALSE;
}
//
// try the next ip addr in the list
//
TCHAR szAddr[16]; // xxx.xxx.xxx.xxx
unsigned char *puc;
pArgs->uiCurrentDnsTunnelAddr++;
puc = pArgs->pucDnsTunnelIpAddr_list + pArgs->rgwRandomDnsIndex[pArgs->uiCurrentDnsTunnelAddr]*4;
wsprintfU(szAddr, TEXT("%hu.%hu.%hu.%hu"),
*puc,
*(puc+1),
*(puc+2),
*(puc+3));
CMTRACE1(TEXT("TryAnotherTunnelDnsAddress: found ip addr %s for the tunnel server"), szAddr);
pArgs->SetPrimaryTunnel(szAddr);
return TRUE;
}
//+---------------------------------------------------------------------------
//
// Function: InvokeGetHostByName
//
// Synopsis: call gethostbyname and sets up internal ipaddr list.
//
// Arguments: pArgs ptr to ArgsStruct
//
// Returns: TRUE if SUCCESS
// FALSE otherwise.
//
//----------------------------------------------------------------------------
BOOL InvokeGetHostByName(
ArgsStruct *pArgs
)
{
HINSTANCE hInst;
PFN_WSAStartup pfnWSAStartup;
PFN_WSACleanup pfnWSACleanup = NULL;
PFN_gethostbyname pfngethostbyname;
WSADATA wsaData;
struct hostent *pHe;
BOOL fOk = FALSE;
#ifdef UNICODE
LPSTR pszHostName;
DWORD dwSize;
#endif
//
// the list's gotta be empty
//
MYDBGASSERT(!pArgs->pucDnsTunnelIpAddr_list);
MYVERIFY(hInst = LoadLibraryExA("wsock32.dll", NULL, 0));
if (!hInst)
{
return FALSE;
}
if (!(pfnWSAStartup = (PFN_WSAStartup)GetProcAddress(hInst, "WSAStartup")))
{
goto exit;
}
if (pfnWSAStartup(MAKEWORD(1, 1), &wsaData))
{
goto exit;
}
pfnWSACleanup = (PFN_WSACleanup)GetProcAddress(hInst, "WSACleanup");
if (!(pfngethostbyname = (PFN_gethostbyname)GetProcAddress(hInst, "gethostbyname")))
{
goto exit;
}
#ifdef UNICODE
pszHostName = WzToSzWithAlloc(pArgs->GetTunnelAddress());
if (pszHostName)
{
pHe = pfngethostbyname(pszHostName);
CmFree(pszHostName);
if (!pHe)
{
goto exit;
}
}
else
{
goto exit;
}
#else
if (!(pHe = pfngethostbyname(pArgs->GetTunnelAddress())))
{
goto exit;
}
#endif
if (BuildDnsTunnelList(pArgs, pHe))
{
fOk = TRUE;
}
exit:
if (pfnWSACleanup)
{
pfnWSACleanup();
}
if (hInst)
{
FreeLibrary(hInst);
}
return fOk;
}
//+---------------------------------------------------------------------------
//
// Function: BuildDnsTunnelList
//
// Synopsis: Build a tunnel address list.
//
// Arguments: pArgs ptr to ArgsStruct
// pHe a ptr to hostent(returned by gethostbyname()).
//
// Returns: TRUE if SUCCESS
// FALSE otherwise.
//
//----------------------------------------------------------------------------
BOOL BuildDnsTunnelList(
ArgsStruct *pArgs,
struct hostent *pHe
)
{
DWORD dwCnt;
//
// see how many addrs we have
//
for (dwCnt=0; pHe->h_addr_list[dwCnt]; dwCnt++)
;
if (dwCnt < 2)
{
return FALSE;
}
//
// if we have more than one addrs, save the list.
//
pArgs->dwDnsTunnelAddrCount = dwCnt;
if (!(pArgs->pucDnsTunnelIpAddr_list = (unsigned char *)CmMalloc(dwCnt*pHe->h_length)))
{
CMTRACE(TEXT("InvokeGetHostByName: failed to alloc tunnel addr list"));
return FALSE;
}
for (dwCnt=0; dwCnt<pArgs->dwDnsTunnelAddrCount; dwCnt++)
{
CopyMemory(pArgs->pucDnsTunnelIpAddr_list + dwCnt*pHe->h_length,
pHe->h_addr_list[dwCnt],
pHe->h_length);
}
pArgs->uiCurrentDnsTunnelAddr = 0;
//
// we need a random list. With this, we can get a random addr in constant
// time(and fast). see cmtools\getips.
//
if (!BuildRandomTunnelIndex(pArgs, dwCnt))
{
CmFree(pArgs->pucDnsTunnelIpAddr_list);
pArgs->pucDnsTunnelIpAddr_list = NULL;
return FALSE;
}
return TRUE;
}
//+---------------------------------------------------------------------------
//
// Function: BuildRandomTunnelIndex
//
// Synopsis: Build a list random indices. With this, we can get a random
// addr in constant time(and fast). see cmtools\getips.
//
// Arguments: pArgs ptr to ArgsStruct
// dwCount # of of indices
//
// Returns: TRUE if SUCCESS
// FALSE otherwise.
//
//----------------------------------------------------------------------------
BOOL BuildRandomTunnelIndex(
ArgsStruct *pArgs,
DWORD dwCount
)
{
DWORD i, j;
PWORD rgwIndex;
WORD wTmp;
//
// we can only have at most 65536 ip addrs(the max. range of a WORD), which is plenty.
//
MYDBGASSERT((dwCount > 1) && (dwCount <= 65536));
if (!(pArgs->rgwRandomDnsIndex = (PWORD)CmMalloc(sizeof(WORD)*dwCount)))
{
return FALSE;
}
//
// now start build the random indices...
//
for (i=0, rgwIndex=pArgs->rgwRandomDnsIndex; i<dwCount; i++)
{
rgwIndex[i] = (WORD)i;
}
#ifdef DEBUG
{
unsigned char *puc;
TCHAR szAddr[16]; // xxx.xxx.xxx.xxx
CMTRACE2(TEXT("BuildRandomTunnelIndex: BEFORE randomization(server=%s, count=%u):"),
pArgs->GetTunnelAddress(), dwCount);
for (i=0; i<dwCount; i++)
{
puc = pArgs->pucDnsTunnelIpAddr_list + i*4;
wsprintfU(szAddr, TEXT("%hu.%hu.%hu.%hu"),
*puc,
*(puc+1),
*(puc+2),
*(puc+3));
CMTRACE2(TEXT("%u: %s"), i, szAddr);
}
}
#endif
//
// If we only have 2 addrs, the first address has already been used by RAS,
// there's no need to randomize the list. We'll just use the 2nd addr.
//
if (dwCount == 2)
{
return TRUE;
}
CRandom r;
//
// randomize the indices. skip the first entry.
//
for (i=1; i<dwCount; i++)
{
do
{
//
// j has to be non-zero(to leave the 0-th entry untouhced).
//
j = r.Generate() % dwCount;
} while (!j);
if (i != j)
{
wTmp = rgwIndex[i];
rgwIndex[i] = rgwIndex[j];
rgwIndex[j] = wTmp;
}
}
#ifdef DEBUG
{
unsigned char *puc;
TCHAR szAddr[16]; // xxx.xxx.xxx.xxx
CMTRACE2(TEXT("BuildRandomTunnelIndex: AFTER randomization(server=%s, count=%u):"),
pArgs->GetTunnelAddress(), dwCount);
for (i=0; i<dwCount; i++)
{
puc = pArgs->pucDnsTunnelIpAddr_list + rgwIndex[i]*4;
wsprintfU(szAddr, TEXT("%hu.%hu.%hu.%hu"),
*puc,
*(puc+1),
*(puc+2),
*(puc+3));
CMTRACE2(TEXT("%u: %s"), i, szAddr);
}
}
#endif
return TRUE;
}