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authorRubidium <rubidium@openttd.org>2021-04-11 11:30:44 +0200
committerPatric Stout <github@truebrain.nl>2021-04-12 21:10:21 +0200
commit7597740bff711d78e3f005bdfad214154281559a (patch)
tree339de4d4bbde9807a65832f7f7a0a7289daa8e70
parentca6b9ad8b0a64ebc812cf2e748d8ea9c874b4860 (diff)
downloadopenttd-7597740bff711d78e3f005bdfad214154281559a.tar.xz
Fix: split the UDP blocking of sockets to only the socket involved, and when another thread is busy do not attempt to process the packets of that socket
-rw-r--r--src/network/network_udp.cpp96
1 files changed, 59 insertions, 37 deletions
diff --git a/src/network/network_udp.cpp b/src/network/network_udp.cpp
index e4276c58f..6d7e6ca69 100644
--- a/src/network/network_udp.cpp
+++ b/src/network/network_udp.cpp
@@ -33,9 +33,6 @@
#include "../safeguards.h"
-/** Mutex for all out threaded udp resolution and such. */
-static std::mutex _network_udp_mutex;
-
/** Session key to register ourselves to the master server */
static uint64 _session_key = 0;
@@ -43,14 +40,46 @@ static const std::chrono::minutes ADVERTISE_NORMAL_INTERVAL(15); ///< interval b
static const std::chrono::seconds ADVERTISE_RETRY_INTERVAL(10); ///< re-advertise when no response after this amount of time.
static const uint32 ADVERTISE_RETRY_TIMES = 3; ///< give up re-advertising after this much failed retries
-NetworkUDPSocketHandler *_udp_client_socket = nullptr; ///< udp client socket
-NetworkUDPSocketHandler *_udp_server_socket = nullptr; ///< udp server socket
-NetworkUDPSocketHandler *_udp_master_socket = nullptr; ///< udp master socket
-
static bool _network_udp_server; ///< Is the UDP server started?
static uint16 _network_udp_broadcast; ///< Timeout for the UDP broadcasts.
static uint8 _network_advertise_retries; ///< The number of advertisement retries we did.
+/** Some information about a socket, which exists before the actual socket has been created to provide locking and the likes. */
+struct UDPSocket {
+ const std::string name; ///< The name of the socket.
+ std::mutex mutex; ///< Mutex for everything that (indirectly) touches the sockets within the handler.
+ NetworkUDPSocketHandler *socket; ///< The actual socket, which may be nullptr when not initialized yet.
+ std::atomic<int> receive_iterations_locked; ///< The number of receive iterations the mutex was locked.
+
+ UDPSocket(const std::string &name_) : name(name_), socket(nullptr) {}
+
+ void Close()
+ {
+ std::lock_guard<std::mutex> lock(mutex);
+ socket->Close();
+ delete socket;
+ socket = nullptr;
+ }
+
+ void ReceivePackets()
+ {
+ std::unique_lock<std::mutex> lock(mutex, std::defer_lock);
+ if (!lock.try_lock()) {
+ if (++receive_iterations_locked % 32 == 0) {
+ DEBUG(net, 0, "[udp] %s background UDP loop processing appears to be blocked. Your OS may be low on UDP send buffers.", name.c_str());
+ }
+ return;
+ }
+
+ receive_iterations_locked.store(0);
+ socket->ReceivePackets();
+ }
+};
+
+static UDPSocket _udp_client("Client"); ///< udp client socket
+static UDPSocket _udp_server("Server"); ///< udp server socket
+static UDPSocket _udp_master("Master"); ///< udp master socket
+
/**
* Helper function doing the actual work for querying the server.
* @param address The address of the server.
@@ -67,11 +96,11 @@ static void DoNetworkUDPQueryServer(NetworkAddress &address, bool needs_mutex, b
item->manually = manually;
NetworkGameListAddItemDelayed(item);
- std::unique_lock<std::mutex> lock(_network_udp_mutex, std::defer_lock);
+ std::unique_lock<std::mutex> lock(_udp_client.mutex, std::defer_lock);
if (needs_mutex) lock.lock();
/* Init the packet */
Packet p(PACKET_UDP_CLIENT_FIND_SERVER);
- if (_udp_client_socket != nullptr) _udp_client_socket->SendPacket(&p, &address);
+ if (_udp_client.socket != nullptr) _udp_client.socket->SendPacket(&p, &address);
}
/**
@@ -479,7 +508,8 @@ void NetworkUDPQueryMasterServer()
p.Send_uint8(NETWORK_MASTER_SERVER_VERSION);
p.Send_uint8(SLT_AUTODETECT);
- _udp_client_socket->SendPacket(&p, &out_addr, true);
+ std::lock_guard<std::mutex> lock(_udp_client.mutex);
+ _udp_client.socket->SendPacket(&p, &out_addr, true);
DEBUG(net, 2, "[udp] master server queried at %s", out_addr.GetAddressAsString().c_str());
}
@@ -492,7 +522,7 @@ void NetworkUDPSearchGame()
DEBUG(net, 0, "[udp] searching server");
- NetworkUDPBroadCast(_udp_client_socket);
+ NetworkUDPBroadCast(_udp_client.socket);
_network_udp_broadcast = 300; // Stay searching for 300 ticks
}
@@ -512,8 +542,8 @@ static void NetworkUDPRemoveAdvertiseThread()
p.Send_uint8 (NETWORK_MASTER_SERVER_VERSION);
p.Send_uint16(_settings_client.network.server_port);
- std::lock_guard<std::mutex> lock(_network_udp_mutex);
- if (_udp_master_socket != nullptr) _udp_master_socket->SendPacket(&p, &out_addr, true);
+ std::lock_guard<std::mutex> lock(_udp_master.mutex);
+ if (_udp_master.socket != nullptr) _udp_master.socket->SendPacket(&p, &out_addr, true);
}
/**
@@ -564,8 +594,8 @@ static void NetworkUDPAdvertiseThread()
p.Send_uint16(_settings_client.network.server_port);
p.Send_uint64(_session_key);
- std::lock_guard<std::mutex> lock(_network_udp_mutex);
- if (_udp_master_socket != nullptr) _udp_master_socket->SendPacket(&p, &out_addr, true);
+ std::lock_guard<std::mutex> lock(_udp_master.mutex);
+ if (_udp_master.socket != nullptr) _udp_master.socket->SendPacket(&p, &out_addr, true);
}
/**
@@ -607,22 +637,22 @@ void NetworkUDPAdvertise()
void NetworkUDPInitialize()
{
/* If not closed, then do it. */
- if (_udp_server_socket != nullptr) NetworkUDPClose();
+ if (_udp_server.socket != nullptr) NetworkUDPClose();
DEBUG(net, 1, "[udp] initializing listeners");
- assert(_udp_client_socket == nullptr && _udp_server_socket == nullptr && _udp_master_socket == nullptr);
+ assert(_udp_client.socket == nullptr && _udp_server.socket == nullptr && _udp_master.socket == nullptr);
- std::lock_guard<std::mutex> lock(_network_udp_mutex);
+ std::scoped_lock lock(_udp_client.mutex, _udp_server.mutex, _udp_master.mutex);
- _udp_client_socket = new ClientNetworkUDPSocketHandler();
+ _udp_client.socket = new ClientNetworkUDPSocketHandler();
NetworkAddressList server;
GetBindAddresses(&server, _settings_client.network.server_port);
- _udp_server_socket = new ServerNetworkUDPSocketHandler(&server);
+ _udp_server.socket = new ServerNetworkUDPSocketHandler(&server);
server.clear();
GetBindAddresses(&server, 0);
- _udp_master_socket = new MasterNetworkUDPSocketHandler(&server);
+ _udp_master.socket = new MasterNetworkUDPSocketHandler(&server);
_network_udp_server = false;
_network_udp_broadcast = 0;
@@ -632,22 +662,16 @@ void NetworkUDPInitialize()
/** Start the listening of the UDP server component. */
void NetworkUDPServerListen()
{
- _network_udp_server = _udp_server_socket->Listen();
+ std::lock_guard<std::mutex> lock(_udp_server.mutex);
+ _network_udp_server = _udp_server.socket->Listen();
}
/** Close all UDP related stuff. */
void NetworkUDPClose()
{
- std::lock_guard<std::mutex> lock(_network_udp_mutex);
- _udp_server_socket->Close();
- _udp_master_socket->Close();
- _udp_client_socket->Close();
- delete _udp_client_socket;
- delete _udp_server_socket;
- delete _udp_master_socket;
- _udp_client_socket = nullptr;
- _udp_server_socket = nullptr;
- _udp_master_socket = nullptr;
+ _udp_client.Close();
+ _udp_server.Close();
+ _udp_master.Close();
_network_udp_server = false;
_network_udp_broadcast = 0;
@@ -657,13 +681,11 @@ void NetworkUDPClose()
/** Receive the UDP packets. */
void NetworkBackgroundUDPLoop()
{
- std::lock_guard<std::mutex> lock(_network_udp_mutex);
-
if (_network_udp_server) {
- _udp_server_socket->ReceivePackets();
- _udp_master_socket->ReceivePackets();
+ _udp_server.ReceivePackets();
+ _udp_master.ReceivePackets();
} else {
- _udp_client_socket->ReceivePackets();
+ _udp_client.ReceivePackets();
if (_network_udp_broadcast > 0) _network_udp_broadcast--;
}
}