Add IPv6/Dual Stack

[12brendon34]

Description

Modifies WinsockNetLayer.cpp to use Dual stack/IPv6 support
fix small flaw in SetupHeadlessServerConsole()

Changes

Add a little helper WinsockNetLayer::IsNumericAddress,
Modify HostGame, AcceptThreadProc

SetupHeadlessServerConsole() now attempts AttachConsole(ATTACH_PARENT_PROCESS) first

Previous Behavior

IPv6 support just didn't exist

Root Cause

It's old

New Behavior

It now uses the IPv6 flags and IP parsing logic

Fix Implementation

bool WinsockNetLayer::HostGame(int port, const char* bindIp)
{
...
	hints.ai_family = AF_UNSPEC;
...
	if (resolvedBindIp == NULL)
		hints.ai_flags = AI_PASSIVE;
	else if (IsNumericAddress(resolvedBindIp))
		hints.ai_flags = AI_NUMERICHOST;
	else
		hints.ai_flags = 0;
...
	DWORD ipv6only = 0;
	setsockopt(s_listenSocket, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&ipv6only, sizeof(ipv6only));
...
}

bool WinsockNetLayer::JoinGame(const char* ip, int port)
{
...
	if (IsNumericAddress(ip))
		hints.ai_flags = AI_NUMERICHOST;
	else
		hints.ai_flags = 0;

	hints.ai_family = AF_UNSPEC;
...
}


bool WinsockNetLayer::IsNumericAddress(const char* addr)
{
	if (addr == NULL)
		return false;

	if (strchr(addr, ':') != NULL)
		return true;// IPv6

	if (inet_addr(addr) != INADDR_NONE)
		return true;// IPv4

	return false;// hostname
}

AI Use Disclosure

No AI was used for this

[void2012]

Related to #498 ?

[12brendon34]

Related to #498 ?

I would say so

[void2012]

Consider collaborating with that PR author

[12brendon34]

Consider collaborating with that PR author

I think I broke IPv4 slightly, need to figure that out first.
maybe not, I just tested on a diff server and it connected fine

[kuwacom]

Consider collaborating with that PR author

Basically, the separated dedicated server works by calling functionality from the Minecraft.Client side, so once these features are merged into main, they will automatically apply here as well.

[void2012]

Okay. Ask someone to test your PR

[12brendon34]

Okay. Ask someone to test your PR

I'll see if I can get someone to test tmr, it's 3:04 AM right now for me.

[12brendon34]

I just realized I think I accidentally reverted some of #722, no clue how I messed that up.
I'll fix that real quick

[12brendon34]

I've amended it now, I'll see if I can get some friends to test it a bit later.

[12brendon34]

I've tested it with one of my friends, it does seem to work quite well.
I'll fix the conflicts tmr and if anyone else wants to test it, feel free to.

[12brendon34]

I think this is suitable to be merged now.
I've done all the testing I can on my setup.