[reSIProcate] Windows Name Resolution

[Dario Bozzali <dario.bozzali@xxxxxxxxxxxxxxxxx>]

Title: Windows Name Resolution

Hello,
I'm using SVN head of Resiprocate stack and I'm facing a problem using Windows Name Resolution.
I defined WIN32_SYNCRONOUS_RESOLUTION_ON_ARES_FAILURE in the project, so in DnsResult.cxx WSALookupService functions are used to resolve names:

void DnsResult::onDnsResult(const DNSResult<DnsHostRecord>& result)
{
...
#ifdef WIN32_SYNCRONOUS_RESOLUTION_ON_ARES_FAILURE
        // Try Windows Name Resolution (not asyncronous)
        WSAQUERYSET QuerySet = { 0 };
        GUID guidServiceTypeUDP = SVCID_UDP(mPort);
        GUID guidServiceTypeTCP = SVCID_TCP(mPort);
        HANDLE hQuery;
        QuerySet.dwSize = sizeof(WSAQUERYSET);
        QuerySet.lpServiceClassId = mTransport == UDP ? &guidServiceTypeUDP : &guidServiceTypeTCP;
        QuerySet.dwNameSpace = NS_ALL;
        QuerySet.lpszServiceInstanceName = (char *)mTarget.c_str();
        if(WSALookupServiceBegin(&QuerySet, LUP_RETURN_ADDR, &hQuery) == 0)
        {
                DWORD dwQuerySize = 256;   // Starting size
                int iRet = 0;
                bool fDone = false;
                LPWSAQUERYSET pQueryResult = (LPWSAQUERYSET) new char[dwQuerySize];
                while(iRet == 0 && pQueryResult)
                {
                        iRet = WSALookupServiceNext(hQuery, 0, &dwQuerySize, pQueryResult);
...

If mTarget is the host name (without DNS suffixes) on which my applicaton is running, then WSALookupServiceNext() fails and WSAGetLastError is 10108.

I changed onDnsResult() method using SVCID_HOSTNAME as service class id (see below) and in this way I'm able to resolve host names:

void DnsResult::onDnsResult(const DNSResult<DnsHostRecord>& result)
{
...
#ifdef WIN32_SYNCRONOUS_RESOLUTION_ON_ARES_FAILURE
        // Try Windows Name Resolution (not asyncronous)
        WSAQUERYSET QuerySet = { 0 };
        HANDLE hQuery;
        QuerySet.dwSize = sizeof(WSAQUERYSET);
        GUID guidServiceTypeHostName = SVCID_HOSTNAME;
        QuerySet.lpServiceClassId = &guidServiceTypeHostName;
        QuerySet.dwNameSpace = NS_ALL;
        QuerySet.lpszServiceInstanceName = (char *)mTarget.c_str();
...

What is your opinion regarding this change?
Is that correct?

Thanks and regards,
Dario.

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