首先是用ICMP检查网络是否连通：
bool Util::CheckInternet()
{
char * SendData = " Data Buffer " ;
LPVOID ReplyBuffer;
DWORD dwRetVal;
HANDLE hIcmpFile;
bool b = false ;
if ((hIcmpFile = IcmpCreateFile()) == INVALID_HANDLE_VALUE)
return false ;
ReplyBuffer = (VOID * ) malloc( sizeof (ICMP_ECHO_REPLY) + sizeof (SendData));
if ((dwRetVal = IcmpSendEcho(hIcmpFile,
inet_addr( " 209.131.36.158 " ), //用的雅虎的一个IP，可能延迟会大一点，用国内的会小一点
SendData, sizeof (SendData),
NULL, ReplyBuffer,
sizeof (ReplyBuffer) + sizeof (ICMP_ECHO_REPLY),
1000 )) != 0 ) {
b = true ;
}
free(ReplyBuffer);
return b;
}
{
char * SendData = " Data Buffer " ;
LPVOID ReplyBuffer;
DWORD dwRetVal;
HANDLE hIcmpFile;
bool b = false ;
if ((hIcmpFile = IcmpCreateFile()) == INVALID_HANDLE_VALUE)
return false ;
ReplyBuffer = (VOID * ) malloc( sizeof (ICMP_ECHO_REPLY) + sizeof (SendData));
if ((dwRetVal = IcmpSendEcho(hIcmpFile,
inet_addr( " 209.131.36.158 " ), //用的雅虎的一个IP，可能延迟会大一点，用国内的会小一点
SendData, sizeof (SendData),
NULL, ReplyBuffer,
sizeof (ReplyBuffer) + sizeof (ICMP_ECHO_REPLY),
1000 )) != 0 ) {
b = true ;
}
free(ReplyBuffer);
return b;
}
很简单的几行代码，没有注释；
如果网络不通的话枚举拨号连接，进行拨号：
bool RASManager::ConnectNetwork()
{
RASENTRYNAME Entries[ 15 ];
DWORD cb,cEntries,dwRet;
Entries[ 0 ].dwSize = sizeof (RASENTRYNAME);
cb = sizeof (Entries);
cEntries = 0 ;
dwRet = ::RasEnumEntries(NULL, NULL, & Entries[ 0 ], & cb, & cEntries); // 如果函数成功，则返回0
if (dwRet == 0 )
{
CHAR szRasEntryName[RAS_MaxEntryName + 1 ] = { 0 };
for (UINT i = 0 ;i < cEntries;i ++ )
strcpy(szRasEntryName,Entries[i].szEntryName);
RASDIALPARAMS rdParams;
DWORD dwRet;
hConn = NULL;
rdParams.dwSize = sizeof (RASDIALPARAMS);
strcpy(rdParams.szEntryName,szRasEntryName);
strcpy(rdParams.szPhoneNumber, " #777 " ); // 我用的3G卡，拨#777号码
strcpy(rdParams.szUserName, " 用户名 " );
strcpy(rdParams.szPassword, " 密码 " );
strcpy(rdParams.szDomain,"");//这个也很重要，指定域，如果不指定这个的话下面注释的两句一定要加上，下边两句的意思是获取最后一次连接成功时的参数信息，如果用下边两句的话连同这行和这行上面的三行都可以省略
// BOOL fPass;
//RasGetEntryDialParams(NULL, & rdParams, & fPass);
dwRet = RasDial(NULL,NULL, & rdParams, 0L ,NULL, & hConn);
if (dwRet != 0 )
{
return false ;
}
return true ;
}
else
{
return false ;
}
}
{
RASENTRYNAME Entries[ 15 ];
DWORD cb,cEntries,dwRet;
Entries[ 0 ].dwSize = sizeof (RASENTRYNAME);
cb = sizeof (Entries);
cEntries = 0 ;
dwRet = ::RasEnumEntries(NULL, NULL, & Entries[ 0 ], & cb, & cEntries); // 如果函数成功，则返回0
if (dwRet == 0 )
{
CHAR szRasEntryName[RAS_MaxEntryName + 1 ] = { 0 };
for (UINT i = 0 ;i < cEntries;i ++ )
strcpy(szRasEntryName,Entries[i].szEntryName);
RASDIALPARAMS rdParams;
DWORD dwRet;
hConn = NULL;
rdParams.dwSize = sizeof (RASDIALPARAMS);
strcpy(rdParams.szEntryName,szRasEntryName);
strcpy(rdParams.szPhoneNumber, " #777 " ); // 我用的3G卡，拨#777号码
strcpy(rdParams.szUserName, " 用户名 " );
strcpy(rdParams.szPassword, " 密码 " );
strcpy(rdParams.szDomain,"");//这个也很重要，指定域，如果不指定这个的话下面注释的两句一定要加上，下边两句的意思是获取最后一次连接成功时的参数信息，如果用下边两句的话连同这行和这行上面的三行都可以省略
// BOOL fPass;
//RasGetEntryDialParams(NULL, & rdParams, & fPass);
dwRet = RasDial(NULL,NULL, & rdParams, 0L ,NULL, & hConn);
if (dwRet != 0 )
{
return false ;
}
return true ;
}
else
{
return false ;
}
}
预先建立拨号连接，以上拨号代码经过修改已经不需要保存密码，只建立一个拨号连接即可。Windows XP or later: Do not use the RasSetEntryDialParams function. MSDN上面的说法就是RasSetEntryDialParams 别在XP之后的系统上使用了。
检查拨号连接的状态，如果已经通过拨号连接上了网络当然不用再进行拨号了，代码如下：
bool RASManager::RasGetConnectStatus()
{
LPRASCONN lpRasConn = NULL;
DWORD cbBuf = 0 ;
DWORD cConn = 0 ;
DWORD dwRet = 0 ;
HRASCONN hrasconn;
bool bResult = FALSE;
RASCONNSTATUS rasStatus;
UINT ndx;
cbBuf = sizeof (RASCONN);
lpRasConn = (LPRASCONN)malloc((UINT)cbBuf);
if (lpRasConn != NULL)
{
lpRasConn -> dwSize = sizeof (RASCONN);
dwRet = RasEnumConnections(lpRasConn, & cbBuf, & cConn);
for (ndx = 0 ;ndx < cConn;ndx ++ )
{
hrasconn = lpRasConn[ndx].hrasconn;
rasStatus.dwSize = sizeof (RASCONNSTATUS);
dwRet = ::RasGetConnectStatus(hrasconn, & rasStatus);
if (dwRet)
bResult = FALSE;
else
{
if (rasStatus.rasconnstate == RASCS_Connected)
bResult = TRUE;
else
bResult = FALSE;
}
}
}
else
bResult = FALSE;
free(lpRasConn);
return bResult;
}
{
LPRASCONN lpRasConn = NULL;
DWORD cbBuf = 0 ;
DWORD cConn = 0 ;
DWORD dwRet = 0 ;
HRASCONN hrasconn;
bool bResult = FALSE;
RASCONNSTATUS rasStatus;
UINT ndx;
cbBuf = sizeof (RASCONN);
lpRasConn = (LPRASCONN)malloc((UINT)cbBuf);
if (lpRasConn != NULL)
{
lpRasConn -> dwSize = sizeof (RASCONN);
dwRet = RasEnumConnections(lpRasConn, & cbBuf, & cConn);
for (ndx = 0 ;ndx < cConn;ndx ++ )
{
hrasconn = lpRasConn[ndx].hrasconn;
rasStatus.dwSize = sizeof (RASCONNSTATUS);
dwRet = ::RasGetConnectStatus(hrasconn, & rasStatus);
if (dwRet)
bResult = FALSE;
else
{
if (rasStatus.rasconnstate == RASCS_Connected)
bResult = TRUE;
else
bResult = FALSE;
}
}
}
else
bResult = FALSE;
free(lpRasConn);
return bResult;
}
以上判断是如果检查到有一个已经连接的拨号连接就返回了，应该不会有两个或者以上的拨号连接同时连接，打开端口会失败的。
还有一个是断线：
void RASManager::HungUP()
{
LPRASCONN lpRasConn = NULL;
DWORD cbBuf = 0 ;
DWORD cConn = 0 ;
DWORD dwRet = 0 ;
HRASCONN hrasconn;
RASCONNSTATUS rasStatus;
UINT ndx;
cbBuf = sizeof (RASCONN);
lpRasConn = (LPRASCONN)malloc((UINT)cbBuf);
if (lpRasConn != NULL)
{
lpRasConn -> dwSize = sizeof (RASCONN);
dwRet = RasEnumConnections(lpRasConn, & cbBuf, & cConn);
for (ndx = 0 ;ndx < cConn;ndx ++ )
{
hrasconn = lpRasConn[ndx].hrasconn;
rasStatus.dwSize = sizeof (RASCONNSTATUS);
dwRet = ::RasGetConnectStatus(hrasconn, & rasStatus);
if ( ! dwRet)
{
if (rasStatus.rasconnstate == RASCS_Connected)
RasHangUp(hrasconn);
}
}
free(lpRasConn);
}
}
{
LPRASCONN lpRasConn = NULL;
DWORD cbBuf = 0 ;
DWORD cConn = 0 ;
DWORD dwRet = 0 ;
HRASCONN hrasconn;
RASCONNSTATUS rasStatus;
UINT ndx;
cbBuf = sizeof (RASCONN);
lpRasConn = (LPRASCONN)malloc((UINT)cbBuf);
if (lpRasConn != NULL)
{
lpRasConn -> dwSize = sizeof (RASCONN);
dwRet = RasEnumConnections(lpRasConn, & cbBuf, & cConn);
for (ndx = 0 ;ndx < cConn;ndx ++ )
{
hrasconn = lpRasConn[ndx].hrasconn;
rasStatus.dwSize = sizeof (RASCONNSTATUS);
dwRet = ::RasGetConnectStatus(hrasconn, & rasStatus);
if ( ! dwRet)
{
if (rasStatus.rasconnstate == RASCS_Connected)
RasHangUp(hrasconn);
}
}
free(lpRasConn);
}
}
这个没什么好说的，执行关闭拨号连接的操作。
用程序创建连接，经过修改，已经可以正常创建连接，代码如下：
bool RASManager::CreateRASLink()
{
LPRASENTRY lpRasEntry = NULL;
DWORD cb = sizeof (RASENTRY);
DWORD dwBufferSize = 0 ;
DWORD dwRet = 0 ;
// 取得entry的大小,这句也不知道是不是必须的,因为sizeof(RASENTRY)和这里取到的dwBufferSize是一样的,不过还是Get一下安全点
RasGetEntryProperties(NULL, "" , NULL, & dwBufferSize, NULL, NULL);
if (dwBufferSize == 0 )
return false ;
lpRasEntry = (LPRASENTRY)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, dwBufferSize);
if (lpRasEntry == NULL)
return false ;
ZeroMemory(lpRasEntry, sizeof (RASENTRY));
lpRasEntry -> dwSize = dwBufferSize;
lpRasEntry -> dwfOptions = RASEO_RemoteDefaultGateway|RASEO_PreviewPhoneNumber|RASEO_PreviewUserPw; // 这里的几个选项挺重要的， RASEO_RemoteDefaultGateway这个选项把创建的连接设置为默认连接， RASEO_PreviewPhoneNumber 对应选项中的提示输入电话号码，RASEO_PreviewUserPw对应选项中的提示用户名和密码
lpRasEntry -> dwType = RASET_Phone;
lstrcpy(lpRasEntry -> szDeviceType, RASDT_Modem);
lstrcpy(lpRasEntry -> szDeviceName, " www " );
lpRasEntry -> dwfNetProtocols = RASNP_Ip;
lpRasEntry -> dwFramingProtocol = RASFP_Ppp;
dwRet = RasSetEntryProperties(NULL, " www " , lpRasEntry, dwBufferSize, NULL, 0 ); // 创建连接
// The RasSetEntryProperties function changes the connection information for an entry in the phone book or creates a new phone-book entry.（reference MSDN）
HeapFree(GetProcessHeap(), 0 , (LPVOID)lpRasEntry);
if (dwRet != 0 )
return false ;
return true ;
}
{
LPRASENTRY lpRasEntry = NULL;
DWORD cb = sizeof (RASENTRY);
DWORD dwBufferSize = 0 ;
DWORD dwRet = 0 ;
// 取得entry的大小,这句也不知道是不是必须的,因为sizeof(RASENTRY)和这里取到的dwBufferSize是一样的,不过还是Get一下安全点
RasGetEntryProperties(NULL, "" , NULL, & dwBufferSize, NULL, NULL);
if (dwBufferSize == 0 )
return false ;
lpRasEntry = (LPRASENTRY)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, dwBufferSize);
if (lpRasEntry == NULL)
return false ;
ZeroMemory(lpRasEntry, sizeof (RASENTRY));
lpRasEntry -> dwSize = dwBufferSize;
lpRasEntry -> dwfOptions = RASEO_RemoteDefaultGateway|RASEO_PreviewPhoneNumber|RASEO_PreviewUserPw; // 这里的几个选项挺重要的， RASEO_RemoteDefaultGateway这个选项把创建的连接设置为默认连接， RASEO_PreviewPhoneNumber 对应选项中的提示输入电话号码，RASEO_PreviewUserPw对应选项中的提示用户名和密码
lpRasEntry -> dwType = RASET_Phone;
lstrcpy(lpRasEntry -> szDeviceType, RASDT_Modem);
lstrcpy(lpRasEntry -> szDeviceName, " www " );
lpRasEntry -> dwfNetProtocols = RASNP_Ip;
lpRasEntry -> dwFramingProtocol = RASFP_Ppp;
dwRet = RasSetEntryProperties(NULL, " www " , lpRasEntry, dwBufferSize, NULL, 0 ); // 创建连接
// The RasSetEntryProperties function changes the connection information for an entry in the phone book or creates a new phone-book entry.（reference MSDN）
HeapFree(GetProcessHeap(), 0 , (LPVOID)lpRasEntry);
if (dwRet != 0 )
return false ;
return true ;
}
上面的代码到是可以创建一个拨号连接，不过是个空的，里面没用用户名和密码等信息，需要用上面的拨号代码来指定拨号参数，不能使用RasGetEntryDialParams来获取了。
上面的代码基本上是在网络上搜索所得，稍加修改，在这里整理一下。
再补充一下删除连接的操作,代码如下：
void RASManager::DeletePhoneBookEntry()
{
RASENTRYNAME Entries[ 15 ];
DWORD cb,cEntries,dwRet;
Entries[ 0 ].dwSize = sizeof (RASENTRYNAME);
cb = sizeof (Entries);
cEntries = 0 ;
dwRet = ::RasEnumEntries(NULL, NULL, & Entries[ 0 ], & cb, & cEntries); // 如果函数成功，则返回0
if (dwRet == 0 )
{
CHAR szRasEntryName[RAS_MaxEntryName + 1 ] = { 0 };
for (UINT i = 0 ;i < cEntries;i ++ )
{
strcpy(szRasEntryName,Entries[i].szEntryName);
RasDeleteEntry(NULL,szRasEntryName);
}
}
}
{
RASENTRYNAME Entries[ 15 ];
DWORD cb,cEntries,dwRet;
Entries[ 0 ].dwSize = sizeof (RASENTRYNAME);
cb = sizeof (Entries);
cEntries = 0 ;
dwRet = ::RasEnumEntries(NULL, NULL, & Entries[ 0 ], & cb, & cEntries); // 如果函数成功，则返回0
if (dwRet == 0 )
{
CHAR szRasEntryName[RAS_MaxEntryName + 1 ] = { 0 };
for (UINT i = 0 ;i < cEntries;i ++ )
{
strcpy(szRasEntryName,Entries[i].szEntryName);
RasDeleteEntry(NULL,szRasEntryName);
}
}
}
要想实现自动启动拨号网络，就要使用 Remote Access Service (RAS) API，这个API最早是在Windows for Workgroup 3.11中出现的，现在它已经成为Win32 API的一个组成部分。该API将整个拨号网络称为Phonebook，而每一个连接称为PhonebookEntry。你可以使用 RasCreatePhonebookEntry来创建新的连接，用RasDial来拨号，而RasEnumEntries可以获得当前系统已有的所有连 接，使用其它的RAS函数还可以获取或设置连接的参数。
RasEditPhonebookEntry函数将激活标准的Windows 95/NT属性对话框来修改连接的属性。你可以从Win32 API的手册找到所有相关函数的详细介绍。
补充：在windows中一个拨号连接即为一个PhonrbookEntry以下称为电话薄记录或是连接。总的这些称为Phonebook。
