Introduce channelcountlimit to limit max channels per server

Having to many channels on a server can impact performance to the point
of making the instance unusably slow. This can be a problem for hosters
that allow their users unlimited channel creation.

This patch introduces a new per-server configuration parameter
channelcountlimit which can be used to configure a maximum number of
channels that may be created on each of the virtual servers. Once the
limit is reached channel creation will be rejected with permission
denied.

To allow a translated error message we have to bump the client version
to 1.3.1 to be able to use a fallback message for older clients.

As usual dbus, ice and grpc can ignore this limit. It is only enforced
against clients.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/murmur/Messages.cpp b/src/murmur/Messages.cpp
index b5d79b85b..900acddc5 100644
--- a/src/murmur/Messages.cpp
+++ b/src/murmur/Messages.cpp
@@ -896,6 +896,11 @@ void Server::msgChannelState(ServerUser *uSource, MumbleProto::ChannelState &msg
 		if (! p || qsName.isNull())
 			return;
 
+		if (iChannelCountLimit == 0 || qhChannels.count() >= iChannelCountLimit) {
+			PERM_DENIED_FALLBACK(ChannelCountLimit, 0x010301, QLatin1String("Channel count limit reached"));
+			return;
+		}
+		
 		ChanACL::Perm perm = msg.temporary() ? ChanACL::MakeTempChannel : ChanACL::MakeChannel;
 		if (! hasPermission(uSource, p, perm)) {
 			PERM_DENIED(uSource, p, perm);