snes9x/server.cpp

/*****************************************************************************\
     Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
                This file is licensed under the Snes9x License.
   For further information, consult the LICENSE file in the root directory.
\*****************************************************************************/

#ifdef NETPLAY_SUPPORT

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <memory.h>
#include <sys/types.h>
#ifdef HAVE_STRINGS_H
	#include <strings.h>
#endif

#include "snes9x.h"

#ifdef __WIN32__

	#include <winsock.h>
	#include <process.h>
	#include "win32/wsnes9x.h"
	#define ioctl ioctlsocket
	#define close closesocket
	#define read(a,b,c) recv(a, b, c, 0)
	#define write(a,b,c) send(a, b, c, 0)
	#define gettimeofday(a,b) S9xGetTimeOfDay (a)
	#define exit(a) _endthread()
	void S9xGetTimeOfDay (struct timeval *n);
#else
	#include <unistd.h>
	#include <sys/time.h>

	#include <netdb.h>
	#include <sys/socket.h>
	#include <sys/param.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <signal.h>

	#ifdef __SVR4
		#include <sys/stropts.h>
	#endif

#endif // !__WIN32__

#include "memmap.h"
#include "snapshot.h"
#include "netplay.h"

#ifdef __WIN32__
#define NP_ONE_CLIENT 1
#else
#define NP_ONE_CLIENT 0
#endif

struct SNPServer NPServer;

extern unsigned long START;

void S9xNPSendToAllClients (uint8 *data, int len);
bool8 S9xNPLoadFreezeFile (const char *fname, uint8 *&data, uint32 &len);
void S9xNPSendFreezeFile (int c, uint8 *data, uint32 len);
void S9xNPNoClientReady (int start_index = NP_ONE_CLIENT);
void S9xNPRecomputePause ();
void S9xNPWaitForEmulationToComplete ();
void S9xNPSendROMImageToAllClients ();
bool8 S9xNPSendROMImageToClient (int client);
void S9xNPSendSRAMToClient (int c);
void S9xNPSendSRAMToAllClients ();
void S9xNPSyncClient (int);
void S9xNPSendROMLoadRequest (const char *filename);
void S9xNPSendFreezeFileToAllClients (const char *filename);
void S9xNPStopServer ();

void S9xNPShutdownClient (int c, bool8 report_error = FALSE)
{
    if (NPServer.Clients [c].Connected)
    {
        NPServer.Clients [c].Connected = FALSE;
        NPServer.Clients [c].SaidHello = FALSE;

        close (NPServer.Clients [c].Socket);
#ifdef NP_DEBUG
        printf ("SERVER: Player %d disconnecting @%ld\n", c + 1, S9xGetMilliTime () - START);
#endif
        if (report_error)
        {
            sprintf (NetPlay.ErrorMsg,
                     "Player %d on '%s' has disconnected.", c + 1,
                     NPServer.Clients [c].HostName);
            S9xNPSetWarning  (NetPlay.ErrorMsg);
        }

        if (NPServer.Clients [c].HostName)
        {
            free ((char *) NPServer.Clients [c].HostName);
            NPServer.Clients [c].HostName = NULL;
        }
        if (NPServer.Clients [c].ROMName)
        {
            free ((char *) NPServer.Clients [c].ROMName);
            NPServer.Clients [c].ROMName = NULL;
        }
        if (NPServer.Clients [c].Who)
        {
            free ((char *) NPServer.Clients [c].Who);
            NPServer.Clients [c].Who = NULL;
        }
        NPServer.Joypads [c] = 0;
        NPServer.NumClients--;
        S9xNPRecomputePause ();
    }
}

static bool8 S9xNPSGetData (int socket, uint8 *data, int length)
{
    int len = length;
    uint8 *ptr = data;

    do
    {
        int num_bytes = len;

        // Read the data in small chunks, allowing this thread to spot an
        // abort request from another thread.
        if (num_bytes > 512)
            num_bytes = 512;

        int got = read (socket, (char *) ptr, num_bytes);
        if (got < 0)
        {
	    if (errno == EINTR
#ifdef EAGAIN
		|| errno == EAGAIN
#endif
#ifdef EWOULDBLOCK
		|| errno == EWOULDBLOCK
#endif
#ifdef WSAEWOULDBLOCK
                || errno == WSAEWOULDBLOCK
#endif
		)
		continue;
#ifdef WSAEMSGSIZE
            if (errno != WSAEMSGSIZE)
                return (FALSE);
            else
            {
                got = num_bytes;
#ifdef NP_DEBUG
                printf ("SERVER: WSAEMSGSIZE, actual bytes %d while receiving data @%d\n", got, S9xGetMilliTime () - START);
#endif
            }
#else
            return (FALSE);
#endif
        }
        else
        if (got == 0)
            return (FALSE);

        len -= got;
        ptr += got;
    } while (len > 0);

    return (TRUE);
}

static bool8 S9xNPSSendData (int fd, const uint8 *data, int length)
{
    int len = length;
    int chunk = length / 50;

    if (chunk < 1024)
        chunk = 1024;

    do
    {
        int num_bytes = len;

        // Write the data in small chunks, allowing this thread to spot an
        // abort request from another thread.
        if (num_bytes > chunk)
            num_bytes = chunk;

	int sent;
	sent = write (fd, (char *) data, len);

	if (sent < 0)
	{
	    if (errno == EINTR
#ifdef EAGAIN
		|| errno == EAGAIN
#endif
#ifdef EWOULDBLOCK
		|| errno == EWOULDBLOCK
#endif
		)
            {
#ifdef NP_DEBUG
                printf ("SERVER: EINTR, EAGAIN or EWOULDBLOCK while sending data @%ld\n", S9xGetMilliTime () - START);
#endif
		continue;
            }
	    return (FALSE);
	}
	else
	if (sent == 0)
	    return (FALSE);
	len -= sent;
	data += sent;
        if (length > 1024)
        {
#ifdef __WIN32__
            int Percent = (uint8) (((length - len) * 100) / length);
            PostMessage (GUI.hWnd, WM_USER, Percent, Percent);
            Sleep (0);
#endif
        }
    } while (len > 0);

    return (TRUE);
}

void S9xNPSendHeartBeat ()
{
    int len = 3;
    uint8 data [3 + 4 * 5];
    uint8 *ptr = data;
    int n;

    for (n = NP_MAX_CLIENTS - 1; n >= 0; n--)
    {
        if (NPServer.Clients [n].SaidHello)
            break;
    }

    if (n >= 0)
    {
        bool8 Paused = NPServer.Paused != 0;

        NPServer.FrameCount++;
        *ptr++ = NP_SERV_MAGIC;
        *ptr++ = 0; // Individual client sequence number will get placed here
        *ptr++ = NP_SERV_JOYPAD | (n << 6) | ((Paused != 0) << 5);

        WRITE_LONG (ptr, NPServer.FrameCount);
        len += 4;
        ptr += 4;

        int i;

        for (i = 0; i <= n; i++)
        {
            WRITE_LONG (ptr, NPServer.Joypads [i]);
            len += 4;
            ptr += 4;
        }

        S9xNPSendToAllClients (data, len);
    }
}

void S9xNPSendToAllClients (uint8 *data, int len)
{
    int i;

    for (i = 0; i < NP_MAX_CLIENTS; i++)
    {
	if (NPServer.Clients [i].SaidHello)
	{
            data [1] = NPServer.Clients [i].SendSequenceNum++;
	    if (!S9xNPSSendData (NPServer.Clients [i].Socket, data, len))
		S9xNPShutdownClient (i, TRUE);
	}
    }
}

void S9xNPProcessClient (int c)
{
    uint8 header [7];
    uint8 *data;
    uint32 len;
    uint8 *ptr;

    if (!S9xNPSGetData (NPServer.Clients [c].Socket, header, 7))
    {
        S9xNPSetWarning ("SERVER: Failed to get message header from client.\n");
        S9xNPShutdownClient (c, TRUE);
        return;
    }
    if (header [0] != NP_CLNT_MAGIC)
    {
        S9xNPSetWarning ("SERVER: Bad header magic value received from client.\n");
        S9xNPShutdownClient (c, TRUE);
        return;
    }

    if (header [1] != NPServer.Clients [c].ReceiveSequenceNum)
    {
#ifdef NP_DEBUG
        printf ("SERVER: Messages lost from '%s', expected %d, got %d\n",
                NPServer.Clients [c].HostName ?
                NPServer.Clients [c].HostName : "Unknown",
                NPServer.Clients [c].ReceiveSequenceNum,
                header [1]);
#endif
        sprintf (NetPlay.WarningMsg,
                 "SERVER: Messages lost from '%s', expected %d, got %d\n",
                NPServer.Clients [c].HostName ?
                NPServer.Clients [c].HostName : "Unknown",
                NPServer.Clients [c].ReceiveSequenceNum,
                header [1]);
        NPServer.Clients [c].ReceiveSequenceNum = header [1] + 1;
        S9xNPSetWarning (NetPlay.WarningMsg);
    }
    else
        NPServer.Clients [c].ReceiveSequenceNum++;

    len = READ_LONG (&header [3]);

    switch (header [2] & 0x3f)
    {
        case NP_CLNT_HELLO:
#ifdef NP_DEBUG
            printf ("SERVER: Got HELLO from client @%ld\n", S9xGetMilliTime () - START);
#endif
            S9xNPSetAction ("Got HELLO from client...", TRUE);
            if (len > 0x10000)
            {
                S9xNPSetWarning ("SERVER: Client HELLO message length error.");
                S9xNPShutdownClient (c, TRUE);
                return;
            }
            data = new uint8 [len - 7];
            if (!S9xNPSGetData (NPServer.Clients [c].Socket, data, len - 7))
            {
                S9xNPSetWarning ("SERVER: Failed to get HELLO message content from client.");
                S9xNPShutdownClient (c, TRUE);
                return;
            }

            if (NPServer.NumClients <= NP_ONE_CLIENT)
            {
		NPServer.FrameTime = READ_LONG (data);
		strncpy (NPServer.ROMName, (char *) &data [4], 29);
		NPServer.ROMName [29] = 0;
            }

            NPServer.Clients [c].ROMName = strdup ((char *) &data [4]);
#ifdef NP_DEBUG
            printf ("SERVER: Client is playing: %s, Frame Time: %d @%ld\n", data + 4, READ_LONG (data), S9xGetMilliTime () - START);
#endif

            NPServer.Clients [c].SendSequenceNum = 0;

            len = 7 + 1 + 1 + 4 + strlen (NPServer.ROMName) + 1;

            delete[] data;
            ptr = data = new uint8 [len];
            *ptr++ = NP_SERV_MAGIC;
            *ptr++ = NPServer.Clients [c].SendSequenceNum++;

            if (NPServer.SendROMImageOnConnect &&
                NPServer.NumClients > NP_ONE_CLIENT)
                *ptr++ = NP_SERV_HELLO | 0x80;
            else
                *ptr++ = NP_SERV_HELLO;
            WRITE_LONG (ptr, len);
            ptr += 4;
            *ptr++ = NP_VERSION;
            *ptr++ = c + 1;
            WRITE_LONG (ptr, NPServer.FrameCount);
            ptr += 4;
            strcpy ((char *) ptr, NPServer.ROMName);

#ifdef NP_DEBUG
            printf ("SERVER: Sending welcome information to client @%ld...\n", S9xGetMilliTime () - START);
#endif
            S9xNPSetAction ("SERVER: Sending welcome information to new client...", TRUE);
            if (!S9xNPSSendData (NPServer.Clients [c].Socket, data, len))
            {
                S9xNPSetWarning ("SERVER: Failed to send welcome message to client.");
                S9xNPShutdownClient (c, TRUE);
                return;
            }
            delete[] data;
#ifdef NP_DEBUG
            printf ("SERVER: Waiting for a response from the client @%ld...\n", S9xGetMilliTime () - START);
#endif
            S9xNPSetAction ("SERVER: Waiting for a response from the client...", TRUE);
            break;

        case NP_CLNT_LOADED_ROM:
#ifdef NP_DEBUG
            printf ("SERVER: Client %d loaded requested ROM @%ld...\n", c, S9xGetMilliTime () - START);
#endif
            NPServer.Clients [c].SaidHello = TRUE;
            NPServer.Clients [c].Ready = FALSE;
            NPServer.Clients [c].Paused = FALSE;
            S9xNPRecomputePause ();
            S9xNPWaitForEmulationToComplete ();

            if (NPServer.SyncByReset)
            {
                S9xNPServerAddTask (NP_SERVER_SEND_SRAM, (void *) (pint) c);
                S9xNPServerAddTask (NP_SERVER_RESET_ALL, 0);
            }
            else
                S9xNPServerAddTask (NP_SERVER_SYNC_CLIENT, (void *) (pint) c);
            break;

        case NP_CLNT_RECEIVED_ROM_IMAGE:
#ifdef NP_DEBUG
            printf ("SERVER: Client %d received ROM image @%ld...\n", c, S9xGetMilliTime () - START);
#endif
            NPServer.Clients [c].SaidHello = TRUE;
            NPServer.Clients [c].Ready = FALSE;
            NPServer.Clients [c].Paused = FALSE;
            S9xNPRecomputePause ();
            S9xNPWaitForEmulationToComplete ();

            if (NPServer.SyncByReset)
            {
                S9xNPServerAddTask (NP_SERVER_SEND_SRAM, (void *) (pint) c);
                S9xNPServerAddTask (NP_SERVER_RESET_ALL, 0);
            }
            else
                S9xNPServerAddTask (NP_SERVER_SYNC_CLIENT, (void *) (pint) c);

            break;

        case NP_CLNT_WAITING_FOR_ROM_IMAGE:
#ifdef NP_DEBUG
            printf ("SERVER: Client %d waiting for ROM image @%ld...\n", c, S9xGetMilliTime () - START);
#endif
            NPServer.Clients [c].SaidHello = TRUE;
            NPServer.Clients [c].Ready = FALSE;
            NPServer.Clients [c].Paused = FALSE;
            S9xNPRecomputePause ();
            S9xNPSendROMImageToClient (c);
            break;

        case NP_CLNT_READY:
#ifdef NP_DEBUG
            printf ("SERVER: Client %d ready @%ld...\n", c, S9xGetMilliTime () - START);
#endif
            if (NPServer.Clients [c].SaidHello)
            {
                NPServer.Clients [c].Paused = FALSE;
                NPServer.Clients [c].Ready = TRUE;

                S9xNPRecomputePause ();
                break;
            }
            NPServer.Clients [c].SaidHello = TRUE;
            NPServer.Clients [c].Ready = TRUE;
            NPServer.Clients [c].Paused = FALSE;
            S9xNPRecomputePause ();

//printf ("SERVER: SaidHello = TRUE, SeqNum = %d @%d\n", NPServer.Clients [c].SendSequenceNum, S9xGetMilliTime () - START);
            if (NPServer.NumClients > NP_ONE_CLIENT)
            {
                if (!NPServer.SendROMImageOnConnect)
                {
                    S9xNPWaitForEmulationToComplete ();

                    if (NPServer.SyncByReset)
                    {
                        S9xNPServerAddTask (NP_SERVER_SEND_SRAM, (void *) (pint) c);
                        S9xNPServerAddTask (NP_SERVER_RESET_ALL, 0);
                    }
                    else
#ifdef __WIN32__
                        S9xNPServerAddTask (NP_SERVER_SYNC_CLIENT, (void *)(UINT_PTR) c);
#else
                        /* We need to resync all clients on new player connect as we don't have a 'reference game' */
                        S9xNPServerAddTask (NP_SERVER_SYNC_ALL, (void *) (pint) c);
#endif
                }
            }
            else
            {
                NPServer.Clients [c].Ready = TRUE;
                S9xNPRecomputePause ();
            }
            break;
        case NP_CLNT_JOYPAD:
            NPServer.Joypads [c] = len;
            break;
        case NP_CLNT_PAUSE:
#ifdef NP_DEBUG
            printf ("SERVER: Client %d Paused: %s @%ld\n", c, (header [2] & 0x80) ? "YES" : "NO", S9xGetMilliTime () - START);
#endif
            NPServer.Clients [c].Paused = (header [2] & 0x80) != 0;
            if (NPServer.Clients [c].Paused)
                sprintf (NetPlay.WarningMsg, "SERVER: Client %d has paused.", c + 1);
            else
                sprintf (NetPlay.WarningMsg, "SERVER: Client %d has resumed.", c + 1);
            S9xNPSetWarning (NetPlay.WarningMsg);
            S9xNPRecomputePause ();
            break;
    }
}

void S9xNPAcceptClient (int Listen, bool8 block)
{
    struct sockaddr_in remote_address;
    struct linger val2;
    struct hostent *host;
    int new_fd;
    int i;

#ifdef NP_DEBUG
    printf ("SERVER: attempting to accept new client connection @%ld\n", S9xGetMilliTime () - START);
#endif
    S9xNPSetAction ("SERVER: Attempting to accept client connection...", TRUE);
    memset (&remote_address, 0, sizeof (remote_address));
    socklen_t len = sizeof (remote_address);

    new_fd = accept (Listen, (struct sockaddr *)&remote_address, &len);

    S9xNPSetAction ("Setting socket options...", TRUE);
    val2.l_onoff = 1;
    val2.l_linger = 0;
    if (setsockopt (new_fd, SOL_SOCKET, SO_LINGER,
		    (char *) &val2, sizeof (val2)) < 0)
    {
        S9xNPSetError ("Setting socket options failed.");
	close (new_fd);
        return;
    }

    for (i = 0; i < NP_MAX_CLIENTS; i++)
    {
	if (!NPServer.Clients [i].Connected)
	{
            NPServer.NumClients++;
	    NPServer.Clients [i].Socket = new_fd;
            NPServer.Clients [i].SendSequenceNum = 0;
            NPServer.Clients [i].ReceiveSequenceNum = 0;
            NPServer.Clients [i].Connected = TRUE;
            NPServer.Clients [i].SaidHello = FALSE;
            NPServer.Clients [i].Paused = FALSE;
            NPServer.Clients [i].Ready = FALSE;
            NPServer.Clients [i].ROMName = NULL;
            NPServer.Clients [i].HostName = NULL;
            NPServer.Clients [i].Who = NULL;
	    break;
	}
    }

    if (i >= NP_MAX_CLIENTS)
    {
        S9xNPSetError ("SERVER: Maximum number of NetPlay Clients have already connected.");
	close (new_fd);
	return;
    }

    if (remote_address.sin_family == AF_INET)
    {
#ifdef NP_DEBUG
        printf ("SERVER: Looking up new client's hostname @%ld\n", S9xGetMilliTime () - START);
#endif
        S9xNPSetAction ("SERVER: Looking up new client's hostname...", TRUE);
	host = gethostbyaddr ((char *) &remote_address.sin_addr,
			      sizeof (remote_address.sin_addr), AF_INET);

	if (host)
	{
#ifdef NP_DEBUG
            printf ("SERVER: resolved new client's hostname (%s) @%ld\n", host->h_name, S9xGetMilliTime () - START);
#endif
	    sprintf (NetPlay.WarningMsg, "SERVER: Player %d on %s has connected.", i + 1, host->h_name);
	    NPServer.Clients [i].HostName = strdup (host->h_name);
	}
        else
        {
            char *ip = inet_ntoa (remote_address.sin_addr);
            if (ip)
                NPServer.Clients [i].HostName = strdup (ip);
#ifdef NP_DEBUG
            printf ("SERVER: couldn't resolve new client's hostname (%s) @%ld\n", ip ? ip : "Unknown", S9xGetMilliTime () - START);
#endif
	    sprintf (NetPlay.WarningMsg, "SERVER: Player %d on %s has connected.", i + 1, ip ? ip : "Unknown");
        }
        S9xNPSetWarning (NetPlay.WarningMsg);
    }
#ifdef NP_DEBUG
    printf ("SERVER: waiting for HELLO message from new client @%ld\n", S9xGetMilliTime () - START);
#endif
    S9xNPSetAction ("SERVER: Waiting for HELLO message from new client...");
}

static bool8 server_continue = TRUE;

static bool8 S9xNPServerInit (int port)
{
    struct sockaddr_in address;
    int i;
    int val;

    if (!S9xNPInitialise ())
        return (FALSE);

    for (i = 0; i < NP_MAX_CLIENTS; i++)
    {
        NPServer.Clients [i].SendSequenceNum = 0;
        NPServer.Clients [i].ReceiveSequenceNum = 0;
        NPServer.Clients [i].Connected = FALSE;
        NPServer.Clients [i].SaidHello = FALSE;
        NPServer.Clients [i].Paused = FALSE;
        NPServer.Clients [i].Ready = FALSE;
        NPServer.Clients [i].Socket = 0;
        NPServer.Clients [i].ROMName = NULL;
        NPServer.Clients [i].HostName = NULL;
        NPServer.Clients [i].Who = NULL;
        NPServer.Joypads [i] = 0;
    }

    NPServer.NumClients = 0;
    NPServer.FrameCount = 0;

#ifdef NP_DEBUG
    printf ("SERVER: Creating socket @%ld\n", S9xGetMilliTime () - START);
#endif
    if ((NPServer.Socket = socket (AF_INET, SOCK_STREAM, 0)) < 0)
    {
	S9xNPSetError ("NetPlay Server: Can't create listening socket.");
	return (FALSE);
    }

    val = 1;
    setsockopt (NPServer.Socket, SOL_SOCKET, SO_REUSEADDR,
                (char *)&val, sizeof (val));

    memset (&address, 0, sizeof (address));
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = htonl (INADDR_ANY);
    address.sin_port = htons (port);

#ifdef NP_DEBUG
    printf ("SERVER: Binding socket to address and port @%ld\n", S9xGetMilliTime () - START);
#endif
    if (bind (NPServer.Socket, (struct sockaddr *) &address, sizeof (address)) < 0)
    {
	S9xNPSetError ("NetPlay Server: Can't bind socket to port number.\nPort already in use?");
	return (FALSE);
    }

#ifdef NP_DEBUG
    printf ("SERVER: Getting socket to listen @%ld\n", S9xGetMilliTime () - START);
#endif
    if (listen (NPServer.Socket, NP_MAX_CLIENTS) < 0)
    {
	S9xNPSetError ("NetPlay Server: Can't get new socket to listen.");
	return (FALSE);
    }

#ifdef NP_DEBUG
    printf ("SERVER: Init complete @%ld\n", S9xGetMilliTime () - START);
#endif
    return (TRUE);
}

void S9xNPSendServerPause (bool8 paused)
{
#ifdef NP_DEBUG
    printf ("SERVER: Pause - %s @%ld\n", paused ? "YES" : "NO", S9xGetMilliTime () - START);
#endif
    uint8 pause [7];
    uint8 *ptr = pause;
    *ptr++ = NP_SERV_MAGIC;
    *ptr++ = 0;
    *ptr++ = NP_SERV_PAUSE | (paused ? 0x20 : 0);
    WRITE_LONG (ptr, NPServer.FrameCount);
    S9xNPSendToAllClients (pause, 7);
}

void S9xNPSendJoypadSwap()
{
#ifdef NP_DEBUG
	printf("SERVER: Swap Joypads - @%ld\n", S9xGetMilliTime() - START);
#endif
	uint8 swap[7];
	uint8 *ptr = swap;
	*ptr++ = NP_SERV_MAGIC;
	*ptr++ = 0;
	*ptr++ = NP_SERV_JOYPAD_SWAP;
	WRITE_LONG(ptr, 7);
	S9xNPSendToAllClients(swap, 7);
}

void S9xNPServerLoop (void *)
{
#ifdef __WIN32__
    BOOL success = FALSE;
#else
    bool8 success = FALSE;
    static struct timeval next1 = {0, 0};
    struct timeval now;
#endif

	int pausedState = -1, newPausedState = -1;

    while (server_continue)
    {
        fd_set read_fds;
        struct timeval timeout;
        int res;
        int i;

        int max_fd = NPServer.Socket;

#ifdef __WIN32__
        Sleep (0);
#endif

        if (success && !(Settings.Paused && !Settings.FrameAdvance) && !Settings.StopEmulation &&
            !Settings.ForcedPause && !NPServer.Paused)
        {
            S9xNPSendHeartBeat ();
			newPausedState = 0;
        }
		else
		{
			newPausedState = 1;
		}

		if(pausedState != newPausedState)
		{
			pausedState = newPausedState;
//			S9xNPSendServerPause(pausedState); // XXX: doesn't seem to work yet...
		}

        do
        {
            FD_ZERO (&read_fds);
            FD_SET (NPServer.Socket, &read_fds);
            for (i = 0; i < NP_MAX_CLIENTS; i++)
            {
                if (NPServer.Clients [i].Connected)
                {
                    FD_SET (NPServer.Clients [i].Socket, &read_fds);
                    if (NPServer.Clients [i].Socket > max_fd)
                        max_fd = NPServer.Clients [i].Socket;
                }
            }

            timeout.tv_sec = 0;
            timeout.tv_usec = 1000;
            res = select (max_fd + 1, &read_fds, NULL, NULL, &timeout);

            if (res > 0)
            {
                if (FD_ISSET (NPServer.Socket, &read_fds))
                    S9xNPAcceptClient (NPServer.Socket, FALSE);

                for (i = 0; i < NP_MAX_CLIENTS; i++)
                {
                    if (NPServer.Clients [i].Connected &&
                        FD_ISSET (NPServer.Clients [i].Socket, &read_fds))
                    {
                        S9xNPProcessClient (i);
                    }
                }
            }
        } while (res > 0);

#ifdef __WIN32__
        success = WaitForSingleObject (GUI.ServerTimerSemaphore, 200) == WAIT_OBJECT_0;
#else
        while (gettimeofday (&now, NULL) < 0) ;

        /* If there is no known "next" frame, initialize it now */
        if (next1.tv_sec == 0) { next1 = now; ++next1.tv_usec; }

	success=FALSE;

	if (timercmp(&next1, &now, >))
        {
            /* If we're ahead of time, sleep a while */
            unsigned timeleft =
                (next1.tv_sec - now.tv_sec) * 1000000
                + next1.tv_usec - now.tv_usec;
	    usleep(timeleft<(200*1000)?timeleft:(200*1000));
        }

        if (!timercmp(&next1, &now, >))
        {

            /* Calculate the timestamp of the next frame. */
            next1.tv_usec += Settings.FrameTime;
            if (next1.tv_usec >= 1000000)
            {
                next1.tv_sec += next1.tv_usec / 1000000;
                next1.tv_usec %= 1000000;
            }
            success=TRUE;
         }
#endif

        while (NPServer.TaskHead != NPServer.TaskTail)
        {
            void *task_data = NPServer.TaskQueue [NPServer.TaskHead].Data;

#if defined(NP_DEBUG) && NP_DEBUG == 2
            printf ("SERVER: task %d @%ld\n", NPServer.TaskQueue [NPServer.TaskHead].Task, S9xGetMilliTime () - START);
#endif

            switch (NPServer.TaskQueue [NPServer.TaskHead].Task)
            {
                case NP_SERVER_SEND_ROM_IMAGE:
                    S9xNPSendROMImageToAllClients ();
                    break;
                case NP_SERVER_SYNC_CLIENT:
                    NPServer.Clients [(pint) task_data].Ready = FALSE;
                    S9xNPRecomputePause ();
                    S9xNPSyncClient ((pint) task_data);
                    break;
                case NP_SERVER_SYNC_ALL:
                    S9xNPSyncClients ();
                    break;
                case NP_SERVER_SEND_FREEZE_FILE_ALL:
                    S9xNPSendFreezeFileToAllClients ((char *) task_data);
                    free ((char *) task_data);
                    break;
                case NP_SERVER_SEND_ROM_LOAD_REQUEST_ALL:
                    S9xNPSendROMLoadRequest ((char *) task_data);
                    free ((char *) task_data);
                    break;
                case NP_SERVER_RESET_ALL:
                    S9xNPNoClientReady (0);
                    S9xNPWaitForEmulationToComplete ();
                    S9xNPSetAction ("SERVER: Sending RESET to all clients...", TRUE);
#ifdef NP_DEBUG
                    printf ("SERVER: Sending RESET to all clients @%ld\n", S9xGetMilliTime () - START);
#endif
                    {
                        uint8 reset [7];
                        uint8 *ptr;

                        ptr = reset;
                        *ptr++ = NP_SERV_MAGIC;
                        *ptr++ = 0;
                        *ptr++ = NP_SERV_RESET;
                        WRITE_LONG (ptr, NPServer.FrameCount);
                        S9xNPSendToAllClients (reset, 7);
                    }
                    S9xNPSetAction ("", TRUE);
                    break;
                case NP_SERVER_SEND_SRAM:
                    NPServer.Clients [(pint) task_data].Ready = FALSE;
                    S9xNPRecomputePause ();
                    S9xNPWaitForEmulationToComplete ();
                    S9xNPSendSRAMToClient ((pint) task_data);
                    break;

                case NP_SERVER_SEND_SRAM_ALL:
                    S9xNPNoClientReady ();
                    S9xNPWaitForEmulationToComplete ();
                    S9xNPSendSRAMToAllClients ();
                    break;

                default:
                    S9xNPSetError ("SERVER: *** Unknown task ***\n");
                    break;
            }
            NPServer.TaskHead = (NPServer.TaskHead + 1) % NP_MAX_TASKS;
        }
    }
#ifdef NP_DEBUG
    printf ("SERVER: Server thread exiting @%ld\n", S9xGetMilliTime () - START);
#endif
    // OV2: S9xNPStopServer has already been called if we get here
    // S9xNPStopServer ();
}

bool8 S9xNPStartServer (int port)
{
#ifdef __WIN32__
    static int p;
    p = port;
#endif

#ifdef NP_DEBUG
    printf ("SERVER: Starting server on port %d @%ld\n", port, S9xGetMilliTime () - START);
#endif

    server_continue = TRUE;
    if (S9xNPServerInit (port))
#ifdef __WIN32__
        return (_beginthread (S9xNPServerLoop, 0, &p) != (uintptr_t)(~0));
#else
    S9xNPServerLoop(NULL);
    return (TRUE);
#endif

    return (FALSE);
}

void S9xNPStopServer ()
{
#ifdef NP_DEBUG
    printf ("SERVER: Stopping server @%ld\n", S9xGetMilliTime () - START);
#endif
    server_continue = FALSE;
    close (NPServer.Socket);

    for (int i = 0; i < NP_MAX_CLIENTS; i++)
    {
        if (NPServer.Clients [i].Connected)
	    S9xNPShutdownClient(i, FALSE);
    }
}

#ifdef __WIN32__
void S9xGetTimeOfDay (struct timeval *n)
{
    unsigned long t = S9xGetMilliTime ();

    n->tv_sec = t / 1000;
    n->tv_usec = (t % 1000) * 1000;
}
#endif

void S9xNPSendROMImageToAllClients ()
{
    S9xNPNoClientReady ();
    S9xNPWaitForEmulationToComplete ();

    int c;

    for (c = NP_ONE_CLIENT; c < NP_MAX_CLIENTS; c++)
    {
        if (NPServer.Clients [c].SaidHello)
            S9xNPSendROMImageToClient (c);
    }

    if (NPServer.SyncByReset)
    {
        S9xNPServerAddTask (NP_SERVER_SEND_SRAM_ALL, 0);
        S9xNPServerAddTask (NP_SERVER_RESET_ALL, 0);
    }
    else
        S9xNPSyncClient (-1);
}

bool8 S9xNPSendROMImageToClient (int c)
{
#ifdef NP_DEBUG
    printf ("SERVER: Sending ROM image to player %d @%ld\n", c + 1, S9xGetMilliTime () - START);
#endif
    sprintf (NetPlay.ActionMsg, "Sending ROM image to player %d...", c + 1);
    S9xNPSetAction (NetPlay.ActionMsg, TRUE);

    uint8 header [7 + 1 + 4];
    uint8 *ptr = header;
    int len = sizeof (header) + Memory.CalculatedSize +
              strlen (Memory.ROMFilename) + 1;
    *ptr++ = NP_SERV_MAGIC;
    *ptr++ = NPServer.Clients [c].SendSequenceNum++;
    *ptr++ = NP_SERV_ROM_IMAGE;
    WRITE_LONG (ptr, len);
    ptr += 4;
    *ptr++ = Memory.HiROM;
    WRITE_LONG (ptr, Memory.CalculatedSize);

    if (!S9xNPSSendData (NPServer.Clients [c].Socket, header, sizeof (header)) ||
        !S9xNPSSendData (NPServer.Clients [c].Socket, Memory.ROM,
                        Memory.CalculatedSize) ||
        !S9xNPSSendData (NPServer.Clients [c].Socket, (uint8 *) Memory.ROMFilename,
                        strlen (Memory.ROMFilename) + 1))
    {
        S9xNPShutdownClient (c, TRUE);
        return (FALSE);
    }
    return (TRUE);
}

void S9xNPSyncClients ()
{
    S9xNPNoClientReady ();
    S9xNPSyncClient (-1);
}

void S9xNPSyncClient (int client)
{
#ifdef HAVE_MKSTEMP
    char fname[] = "/tmp/snes9x_fztmpXXXXXX";
    int fd=-1;
#else
    char fname [L_tmpnam];
#endif

    S9xNPWaitForEmulationToComplete ();

    S9xNPSetAction ("SERVER: Freezing game...", TRUE);
#ifdef HAVE_MKSTEMP
    if ( ((fd=mkstemp(fname)) >= 0) && S9xFreezeGame(fname) )
#else
    if ( tmpnam(fname) && S9xFreezeGame(fname) )
#endif
    {
        uint8 *data;
        uint32 len;

        S9xNPSetAction ("SERVER: Loading freeze file...", TRUE);
        if (S9xNPLoadFreezeFile (fname, data, len))
        {
            int c;

            if (client < 0)
            {
                for (c = NP_ONE_CLIENT; c < NP_MAX_CLIENTS; c++)
                {
                    if (NPServer.Clients [c].SaidHello)
                    {
                        NPServer.Clients [c].Ready = FALSE;
                        S9xNPRecomputePause ();
                        S9xNPSendFreezeFile (c, data, len);
                    }
                }
            }
            else
            {
                NPServer.Clients [client].Ready = FALSE;
                S9xNPRecomputePause ();
                S9xNPSendFreezeFile (client, data, len);
            }
            delete data;
        }
        remove (fname);
    }
#ifdef HAVE_MKSTEMP
    if (fd != -1)
        close(fd);
#endif
}

bool8 S9xNPLoadFreezeFile (const char *fname, uint8 *&data, uint32 &len)
{
    FILE *ff;

    if ((ff = fopen (fname, "rb")))
    {
        fseek (ff, 0, SEEK_END);
        len = ftell (ff);
        fseek (ff, 0, SEEK_SET);

        data = new uint8 [len];
        bool8 ok = (fread (data, 1, len, ff) == len);
        fclose (ff);

        return (ok);
    }
    return (FALSE);
}

void S9xNPSendFreezeFile (int c, uint8 *data, uint32 len)
{
#ifdef NP_DEBUG
    printf ("SERVER: Sending freeze file to player %d @%ld\n", c + 1, S9xGetMilliTime () - START);
#endif

    sprintf (NetPlay.ActionMsg, "SERVER: Sending freeze-file to player %d...", c + 1);
    S9xNPSetAction (NetPlay.ActionMsg, TRUE);
    uint8 header [7 + 4];
    uint8 *ptr = header;

    *ptr++ = NP_SERV_MAGIC;
    *ptr++ = NPServer.Clients [c].SendSequenceNum++;
    *ptr++ = NP_SERV_FREEZE_FILE;
    WRITE_LONG (ptr, len + 7 + 4);
    ptr += 4;
    WRITE_LONG (ptr, NPServer.FrameCount);

    if (!S9xNPSSendData (NPServer.Clients [c].Socket, header, 7 + 4) ||
        !S9xNPSSendData (NPServer.Clients [c].Socket, data, len))
    {
       S9xNPShutdownClient (c, TRUE);
    }
    S9xNPSetAction ("", TRUE);
}

void S9xNPRecomputePause ()
{
    int c;

    for (c = 0; c < NP_MAX_CLIENTS; c++)
    {
        if (NPServer.Clients [c].SaidHello &&
            (!NPServer.Clients [c].Ready || NPServer.Clients [c].Paused))
        {
#if defined(NP_DEBUG) && NP_DEBUG == 2
            printf ("SERVER: Paused because of client %d (%d,%d) @%ld\n", c, NPServer.Clients [c].Ready, NPServer.Clients [c].Paused, S9xGetMilliTime () - START);
#endif
            NPServer.Paused = TRUE;
            return;
        }
    }
#if defined(NP_DEBUG) && NP_DEBUG == 2
    printf ("SERVER: not paused @%ld\n", S9xGetMilliTime () - START);
#endif
    NPServer.Paused = FALSE;
}

void S9xNPNoClientReady (int start_index)
{
    int c;

    for (c = start_index; c < NP_MAX_CLIENTS; c++)
        NPServer.Clients [c].Ready = FALSE;
    S9xNPRecomputePause ();
}

void S9xNPSendROMLoadRequest (const char *filename)
{
    S9xNPNoClientReady ();

    int len = 7 + strlen (filename) + 1;
    uint8 *data = new uint8 [len];
    uint8 *ptr = data;
    *ptr++ = NP_SERV_MAGIC;
    *ptr++ = 0;
    *ptr++ = NP_SERV_LOAD_ROM;
    WRITE_LONG (ptr, len);
    ptr += 4;
    strcpy ((char *) ptr, filename);

    for (int i = NP_ONE_CLIENT; i < NP_MAX_CLIENTS; i++)
    {
	if (NPServer.Clients [i].SaidHello)
	{
#ifdef NP_DEBUG
            printf ("SERVER: Sending load ROM requesting to player %d @%ld\n", i + 1, S9xGetMilliTime () - START);
#endif
            sprintf (NetPlay.WarningMsg, "SERVER: sending ROM load request to player %d...", i + 1);
            S9xNPSetAction (NetPlay.WarningMsg, TRUE);
            data [1] = NPServer.Clients [i].SendSequenceNum++;
	    if (!S9xNPSSendData (NPServer.Clients [i].Socket, data, len))
            {
		S9xNPShutdownClient (i, TRUE);
            }
        }
    }
    delete[] data;
}

void S9xNPSendSRAMToAllClients ()
{
    int i;

    for (i = NP_ONE_CLIENT; i < NP_MAX_CLIENTS; i++)
    {
        if (NPServer.Clients [i].SaidHello)
            S9xNPSendSRAMToClient (i);
    }
}

void S9xNPSendSRAMToClient (int c)
{
#ifdef NP_DEBUG
    printf ("SERVER: Sending S-RAM data to player %d @%ld\n", c + 1, S9xGetMilliTime () - START);
#endif
    uint8 sram [7];
    int SRAMSize = Memory.SRAMSize ?
                   (1 << (Memory.SRAMSize + 3)) * 128 : 0;
    if (Memory.LoROM)
        SRAMSize = SRAMSize < 0x70000 ? SRAMSize : 0x70000;
	else if (Memory.HiROM)
		SRAMSize = SRAMSize < 0x40000 ? SRAMSize : 0x40000;

    int len = 7 + SRAMSize;

    sprintf (NetPlay.ActionMsg, "SERVER: Sending S-RAM to player %d...", c + 1);
    S9xNPSetAction (NetPlay.ActionMsg, TRUE);

    uint8 *ptr = sram;
    *ptr++ = NP_SERV_MAGIC;
    *ptr++ = NPServer.Clients [c].SendSequenceNum++;
    *ptr++ = NP_SERV_SRAM_DATA;
    WRITE_LONG (ptr, len);
    if (!S9xNPSSendData (NPServer.Clients [c].Socket,
                        sram, sizeof (sram)) ||
        (len > 7 &&
         !S9xNPSSendData (NPServer.Clients [c].Socket,
                         Memory.SRAM, len - 7)))
    {
        S9xNPShutdownClient (c, TRUE);
    }
}

void S9xNPSendFreezeFileToAllClients (const char *filename)
{
    uint8 *data;
    uint32 len;

    if (NPServer.NumClients > NP_ONE_CLIENT && S9xNPLoadFreezeFile (filename, data, len))
    {
        S9xNPNoClientReady ();

        for (int c = NP_ONE_CLIENT; c < NP_MAX_CLIENTS; c++)
        {
            if (NPServer.Clients [c].SaidHello)
                S9xNPSendFreezeFile (c, data, len);
        }
        delete data;
    }
}

void S9xNPServerAddTask (uint32 task, void *data)
{
    NPServer.TaskQueue [NPServer.TaskTail].Task = task;
    NPServer.TaskQueue [NPServer.TaskTail].Data = data;

    NPServer.TaskTail = (NPServer.TaskTail + 1) % NP_MAX_TASKS;
}

void S9xNPReset ()
{
    S9xNPNoClientReady (0);
    S9xNPServerAddTask (NP_SERVER_RESET_ALL, 0);
}

void S9xNPWaitForEmulationToComplete ()
{
#ifdef NP_DEBUG
    printf ("SERVER: WaitForEmulationToComplete start @%ld\n", S9xGetMilliTime () - START);
#endif

    while (!NetPlay.PendingWait4Sync && NetPlay.Connected &&
           !Settings.ForcedPause && !Settings.StopEmulation &&
           !(Settings.Paused && !Settings.FrameAdvance))
    {
#ifdef __WIN32__
        Sleep (40);
#endif
    }
#ifdef NP_DEBUG
    printf ("SERVER: WaitForEmulationToComplete end @%ld\n", S9xGetMilliTime () - START);
#endif
}

void S9xNPServerQueueSyncAll ()
{
    if (Settings.NetPlay && Settings.NetPlayServer &&
        NPServer.NumClients > NP_ONE_CLIENT)
    {
        S9xNPNoClientReady ();
        S9xNPDiscardHeartbeats ();
        S9xNPServerAddTask (NP_SERVER_SYNC_ALL, 0);
    }
}

void S9xNPServerQueueSendingROMImage ()
{
    if (Settings.NetPlay && Settings.NetPlayServer &&
        NPServer.NumClients > NP_ONE_CLIENT)
    {
        S9xNPNoClientReady ();
        S9xNPDiscardHeartbeats ();
        S9xNPServerAddTask (NP_SERVER_SEND_ROM_IMAGE, 0);
    }
}

void S9xNPServerQueueSendingFreezeFile (const char *filename)
{
    if (Settings.NetPlay && Settings.NetPlayServer &&
        NPServer.NumClients > NP_ONE_CLIENT)
    {
        S9xNPNoClientReady ();
        S9xNPDiscardHeartbeats ();
        S9xNPServerAddTask (NP_SERVER_SEND_FREEZE_FILE_ALL,
                            (void *) strdup (filename));
    }
}

void S9xNPServerQueueSendingLoadROMRequest (const char *filename)
{
    if (Settings.NetPlay && Settings.NetPlayServer &&
        NPServer.NumClients > NP_ONE_CLIENT)
    {
        S9xNPNoClientReady ();
        S9xNPDiscardHeartbeats ();
        S9xNPServerAddTask (NP_SERVER_SEND_ROM_LOAD_REQUEST_ALL,
                            (void *) strdup (filename));
    }
}

#ifndef __WIN32__
uint32 S9xGetMilliTime ()
{
    static bool8 first = TRUE;
    static long start_sec;
    struct timeval tv;

    gettimeofday (&tv, NULL);
    if (first)
    {
	start_sec = tv.tv_sec;
	first = FALSE;
    }
    return ((uint32) ((tv.tv_sec - start_sec) * 1000 + tv.tv_usec / 1000));
}
#endif
#endif