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Disable port reuse on bind by default and add a setting to configure it.
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@dwilliamson
dwilliamson committed Mar 22, 2018
1 parent d7df158 commit 6a37e7f
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Showing 2 changed files with 37 additions and 23 deletions.
54 changes: 31 additions & 23 deletions lib/Remotery.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2244,11 +2244,10 @@ static void TCPSocket_Destructor(TCPSocket* tcp_socket)
}


static rmtError TCPSocket_RunServer(TCPSocket* tcp_socket, rmtU16 port, rmtBool limit_connections_to_localhost)
static rmtError TCPSocket_RunServer(TCPSocket* tcp_socket, rmtU16 port, rmtBool reuse_open_port, rmtBool limit_connections_to_localhost)
{
SOCKET s = INVALID_SOCKET;
struct sockaddr_in sin;
int enable = 1;
#ifdef RMT_PLATFORM_WINDOWS
u_long nonblock = 1;
#endif
Expand All @@ -2261,19 +2260,24 @@ static rmtError TCPSocket_RunServer(TCPSocket* tcp_socket, rmtU16 port, rmtBool
if (s == SOCKET_ERROR)
return RMT_ERROR_SOCKET_CREATE_FAIL;

// set SO_REUSEADDR so binding doesn't fail when restarting the application
// (otherwise the same port can't be reused within TIME_WAIT)
// I'm not checking for errors because if this fails (unlikely) we might still
// be able to bind to the socket anyway
#ifdef RMT_PLATFORM_POSIX
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
#elif defined(RMT_PLATFORM_WINDOWS)
// windows also needs SO_EXCLUSEIVEADDRUSE,
// see http://www.andy-pearce.com/blog/posts/2013/Feb/so_reuseaddr-on-windows/
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&enable, sizeof(enable));
enable = 1;
setsockopt(s, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *)&enable, sizeof(enable));
#endif
if (reuse_open_port)
{
int enable = 1;

// set SO_REUSEADDR so binding doesn't fail when restarting the application
// (otherwise the same port can't be reused within TIME_WAIT)
// I'm not checking for errors because if this fails (unlikely) we might still
// be able to bind to the socket anyway
#ifdef RMT_PLATFORM_POSIX
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
#elif defined(RMT_PLATFORM_WINDOWS)
// windows also needs SO_EXCLUSEIVEADDRUSE,
// see http://www.andy-pearce.com/blog/posts/2013/Feb/so_reuseaddr-on-windows/
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&enable, sizeof(enable));
enable = 1;
setsockopt(s, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *)&enable, sizeof(enable));
#endif
}

// Bind the socket to the incoming port
sin.sin_family = AF_INET;
Expand Down Expand Up @@ -3153,12 +3157,12 @@ static void WebSocket_Destructor(WebSocket* web_socket)
}


static rmtError WebSocket_RunServer(WebSocket* web_socket, rmtU16 port, rmtBool limit_connections_to_localhost, enum WebSocketMode mode)
static rmtError WebSocket_RunServer(WebSocket* web_socket, rmtU16 port, rmtBool reuse_open_port, rmtBool limit_connections_to_localhost, enum WebSocketMode mode)
{
// Create the server's listening socket
assert(web_socket != NULL);
web_socket->mode = mode;
return TCPSocket_RunServer(web_socket->tcp_socket, port, limit_connections_to_localhost);
return TCPSocket_RunServer(web_socket->tcp_socket, port, reuse_open_port, limit_connections_to_localhost);
}


Expand Down Expand Up @@ -3637,6 +3641,8 @@ typedef struct
rmtU32 last_ping_time;

rmtU16 port;

rmtBool reuse_open_port;
rmtBool limit_connections_to_localhost;

// A dynamically-sized buffer used for binary-encoding messages and sending to the client
Expand All @@ -3648,19 +3654,19 @@ typedef struct
} Server;


static rmtError Server_CreateListenSocket(Server* server, rmtU16 port, rmtBool limit_connections_to_localhost)
static rmtError Server_CreateListenSocket(Server* server, rmtU16 port, rmtBool reuse_open_port, rmtBool limit_connections_to_localhost)
{
rmtError error = RMT_ERROR_NONE;

New_1(WebSocket, server->listen_socket, NULL);
if (error == RMT_ERROR_NONE)
error = WebSocket_RunServer(server->listen_socket, port, limit_connections_to_localhost, WEBSOCKET_BINARY);
error = WebSocket_RunServer(server->listen_socket, port, reuse_open_port, limit_connections_to_localhost, WEBSOCKET_BINARY);

return error;
}


static rmtError Server_Constructor(Server* server, rmtU16 port, rmtBool limit_connections_to_localhost)
static rmtError Server_Constructor(Server* server, rmtU16 port, rmtBool reuse_open_port, rmtBool limit_connections_to_localhost)
{
rmtError error;

Expand All @@ -3669,6 +3675,7 @@ static rmtError Server_Constructor(Server* server, rmtU16 port, rmtBool limit_co
server->client_socket = NULL;
server->last_ping_time = 0;
server->port = port;
server->reuse_open_port = reuse_open_port;
server->limit_connections_to_localhost = limit_connections_to_localhost;
server->bin_buf = NULL;
server->receive_handler = NULL;
Expand All @@ -3680,7 +3687,7 @@ static rmtError Server_Constructor(Server* server, rmtU16 port, rmtBool limit_co
return error;

// Create the listening WebSocket
return Server_CreateListenSocket(server, port, limit_connections_to_localhost);
return Server_CreateListenSocket(server, port, reuse_open_port, limit_connections_to_localhost);
}


Expand Down Expand Up @@ -3769,7 +3776,7 @@ static void Server_Update(Server* server)

// Recreate the listening socket if it's been destroyed earlier
if (server->listen_socket == NULL)
Server_CreateListenSocket(server, server->port, server->limit_connections_to_localhost);
Server_CreateListenSocket(server, server->port, server->reuse_open_port, server->limit_connections_to_localhost);

if (server->listen_socket != NULL && server->client_socket == NULL)
{
Expand Down Expand Up @@ -4867,7 +4874,7 @@ static rmtError Remotery_Constructor(Remotery* rmt)
return error;

// Create the server
New_2(Server, rmt->server, g_Settings.port, g_Settings.limit_connections_to_localhost);
New_3(Server, rmt->server, g_Settings.port, g_Settings.reuse_open_port, g_Settings.limit_connections_to_localhost);
if (error != RMT_ERROR_NONE)
return error;

Expand Down Expand Up @@ -5048,6 +5055,7 @@ RMT_API rmtSettings* _rmt_Settings(void)
if( g_SettingsInitialized == RMT_FALSE )
{
g_Settings.port = 0x4597;
g_Settings.reuse_open_port = RMT_FALSE;
g_Settings.limit_connections_to_localhost = RMT_FALSE;
g_Settings.msSleepBetweenServerUpdates = 10;
g_Settings.messageQueueSizeInBytes = 128 * 1024;
Expand Down
6 changes: 6 additions & 0 deletions lib/Remotery.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -356,6 +356,12 @@ typedef struct rmtSettings
// Which port to listen for incoming connections on
rmtU16 port;

// When this server exits it can leave the port open in TIME_WAIT state for
// a while. This forces subsequent server bind attempts to fail when
// restarting. If you find restarts fail repeatedly with bind attempts, set
// this to true to forcibly reuse the open port.
rmtBool reuse_open_port;

// Only allow connections on localhost?
// For dev builds you may want to access your game from other devices but if
// you distribute a game to your players with Remotery active, probably best
Expand Down

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