A race condition happens when an IPv6 connection takes more than
250ms to report an error, but does return before the IPv4 connection
is established.
In result, an invalid socket might be used for that connection.
This gives user visual feedback that the refresh is still pending, and
prevents people from clicking again and again thinking nothing is
happening. This is especially true for connections that fall back to
TURN, as that takes a few seconds to kick in.
Additionally, prevent clicking on the button again while a refresh
is pending. This is only delaying a successful result.
The function clears all stun-handlers. This causes all of those
objects to be destroyed.
A handler can have a pending connecter, which was only killed in
case CloseConnection() was called. This is never the case when
the object is destroyed. In result, the connecter could finish
and cause a use-after-free by calling into the (now deleted)
handler.
When you are query several servers at once, it is rather unclear
for which server you got a popup. Instead, show any errors on the
server itself.
This is only true for the query-part. Joining a server still gives
an error popup to tell you about any issue.
You can now still query a full server, as long as the maximum
amount of allowed connections isn't reached. This means that as
long as there are not 255 clients connected to a server, you can
always connect to query.
Old servers don't tell the GameScript they are running, so nothing
should be shown.
All values in NetworkGameInfo initialize as 0/empty, except for GS
version. Someone has to be different from the rest, I guess.
Nobody really paid attention to the lobby window, and it completely
missed its purpose. Most people don't even wait for companies to
show up, but just hit "New Company".
This in turn means people create a lot of unneeded companies, while
they "just want to watch the game" or join another company.
Instead, "Join Game" now just joins the game as spectators.
Soon we will make "join game" join the game as spectator first,
so limiting the amount of spectators makes no sense anymore in
that context. Not sure it ever did make sense.
"my_client" wasn't always free'd when a game ended. "my_client"
keeps a reference inside the PT_NCLIENT pool. The rest of the
code assumes that when you are not in a game, it can freely
reset this pool.
In result: several ways to trigger a use-after-free.
TURN is a last resort, used only if all other methods failed.
TURN is a relay approach to connect client and server together, where
openttd.org (by default) is the middleman.
It is very unlikely either the client or server cannot connect to
the STUN server, as they are both already connected to the Game
Coordinator. But in the odd case it does fail, estabilishing the
connection fails without any further possibility to recover.
Before 8a2da49 the NewGRF names were synchronized using UDP packets, however
those have been removed. With this a new version of the GameInfo packet is
introduced that allows to specify the type of serialisation happens for
NewGRFs. Either only the GRF ID and checksum, or those two plus the name of
the NewGRF.
On this request for local servers will send the NewGRFs names.
The Game Coordinator will get the names on the first registration, and after
that only the GRF ID and checksum.
These were filled with "<Unknown>" (before 8a2da49) and later their name would get filled via UDP requests to the server. These UDP packets do not exist anymore, so they will always remain "<Unknown>".
Remove that logic and just use the generic translated error GRF UNKNOWN string instead.
This method doesn't require port-forwarding to be used, and works for
most common NAT routers in home setups. But, for sure it doesn't work
for all setups, and not everyone will be able to use this.
Every outgoing connection, either TCP or UDP, triggered
NetworkInitialize(), which triggered NetworkUDPInitialize() which
first closes all connections.
Now the problem was that "Search LAN games" found a server, added
it to the list, after which (over TCP) it queries the server. This
closes all UDP sockets (as that makes sense, I guess?), while the
UDP was still reading from it.
Solve this by simply stop initializing UDP every time we make an
outgoing TCP connection; instead only do it on start-up.
In this mode you do register to the Game Coordinator, but your
server will not show up in the public server listing. You can give
your friends the invite code of the server with which they can
join.
