Creating listening socket seems to now be having IPv4/IPv6 issues

[fearworksmedia]

When creating a listening socket, to create a webserver for example, I just discovered on my Windows 10 and Windows 11 installs that the webserver would only respond on localhost. Trying 127.0.0.1 would not work, nor would the IPv4 address assigned to the PC. It looks like Windows has had some sort of update that, by default, is using IPv6 over IPv4, and the listening socket is defaulting to the IPv6 socket it finds first.

Sure enough when I change:

DWORD dwResult = getaddrinfo(NULL, pService, &hints, &result);

to:

DWORD dwResult = getaddrinfo("1.2.3.4", pService, &hints, &result);

to force the DLL to only look for that particular address, the listening socket is then created on that specific IP address.

I am guessing that at some point very recently Windows has changed from retrieving IPv4 information first by default, to retrieiving IPv6 information first by default, when using getaddrinfo.

To go along with this, I would propose adding functionality that retrieves a list of the IPv4 and IPv6 addressses on the system to allow the user to then choose and specify the one they want when creating the listening socket.

I will attempt to add a pull request with modified code but it may get ugly because I don't really know what I am doing... feel free to stop me, and correct me if anything I have said is inaccurate. It is my interpretation based on a few MSDN and Stackflow pages I have researched, and I may be misunderstanding, misinterpreting or just downright imagining stuff that isn't true.

[fearworksmedia]

OK I think I came up with something. It seems to work but it is very, very dirty and I'm probably doing all the wrong things in the most despicable way possible, like retrieving IP address as a list separated by new line characters.

I'm sure you (Chris) will probably rewrite this completely or even tell me it's not necessary and something else just needed tweaking, but for now it seems to get the job done.

This is what I came up with in the LB code for printing the IP addresses:

bufLen = 1024
buf$ = space$(bufLen)
ret = RetrieveAddresses(buf$,bufLen)
'ret will contain the number of IP addresses found, including both IPv4 and IPv6
if ret > 0 then print trim$(buf$) 'this contains newline characters but I didn't know how else to get this info back to LB!

Function RetrieveAddresses(byref buf$, bufLen)
CallDLL #LBNet, "RetrieveAddresses",_
buf$ as ptr,_
bufLen as long,_
RetrieveAddresses as long
End Function

Sorry, no error checking. I barely know what I am doing as it is...

And I added in the IP address to the two functions that create listening sockets:

hHTTP = CreateListenSocket("127.0.0.1","80")

and

hSock = UDPCreateListenSocket("127.0.0.1","50000")

Function CreateListenSocket(address$,pService$)
address$ = address$ + chr$(0)
CallDLL #LBNet, "CreateListenSocket",_
address$ as ptr,_
pService$ as ptr,_
CreateListenSocket as ulong
End Function

Function UDPCreateListenSocket(address$,pService$)
address$ = address$ + chr$(0)
CallDLL #LBNet, "UDPCreateListenSocket",_
address$ as ptr,_
pService$ as ptr,_
UDPCreateListenSocket as long
End Function

I know, it's a dreadful mess - but I think it works!?!?