server/socket/loop.c


/*
 * static char *rcsid_loop_c =
 *    "$Id$";
 */

/*
    CrossFire, A Multiplayer game for X-windows

    Copyright (C) 2002-2003 Mark Wedel & The Crossfire Development Team
    Copyright (C) 1992 Frank Tore Johansen

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    The author can be reached via e-mail to crossfire-devel@real-time.com
*/

/**
 * \file
 * Main client/server loops.
 *
 * \date 2003-12-02
 *
 * loop.c mainly deals with initialization and higher level socket
 * maintenance (checking for lost connections and if data has arrived.)
 * The reading of data is handled in ericserver.c
 */


#include <global.h>
#ifndef __CEXTRACT__
#include <sproto.h>
#include <sockproto.h>
#endif

#ifndef WIN32 /* ---win32 exclude unix headers */
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#endif /* end win32 */

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif

#include <loader.h>
#include <newserver.h>

/*****************************************************************************
 * Start of command dispatch area.
 * The commands here are protocol commands. 
 ****************************************************************************/

/* Either keep this near the start or end of the file so it is
 * at least reasonablye easy to find.
 * There are really 2 commands - those which are sent/received
 * before player joins, and those happen after the player has joined.
 * As such, we have function types that might be called, so
 * we end up having 2 tables.
 */

typedef void (*func_uint8_int_ns) (char*, int, NewSocket *);

struct NsCmdMapping {
    const char *cmdname;
    func_uint8_int_ns  cmdproc;
};

typedef void (*func_uint8_int_pl)(char*, int, player *);
struct PlCmdMapping {
    const char *cmdname;
    func_uint8_int_pl cmdproc;
    uint8   flag;
};

/**
 * Dispatch table for the server.
 *
 * CmdMapping is the dispatch table for the server, used in HandleClient,
 * which gets called when the client has input.  All commands called here 
 * use the same parameter form (char* data, int len, int clientnum.
 * We do implicit casts, because the data that is being passed is
 * unsigned (pretty much needs to be for binary data), however, most
 * of these treat it only as strings, so it makes things easier
 * to cast it here instead of a bunch of times in the function itself.
 * flag is 1 if the player must be in the playing state to issue the
 * command, 0 if they can issue it at any time.
 */
static struct PlCmdMapping plcommands[] = {
    { "examine",        ExamineCmd,     1},
    { "apply",          ApplyCmd,       1},
    { "move",           MoveCmd,        1},
    { "reply",          ReplyCmd,       0},
    { "command",        PlayerCmd,      1},
    { "ncom",           (func_uint8_int_pl)NewPlayerCmd, 1},
    { "lookat",         LookAt,         1},
    { "lock",           (func_uint8_int_pl)LockItem,    1},
    { "mark",           (func_uint8_int_pl)MarkItem,    1},
    { "mapredraw",      MapRedrawCmd,   0},     /* Added: phil */
    { "mapinfo",        MapInfoCmd,     2},   /* CF+ */
    { NULL, NULL, 0}    /* terminator */
};

/** Face-related commands */
static struct NsCmdMapping nscommands[] = {
    { "addme",          AddMeCmd },
    { "askface",        SendFaceCmd},   /* Added: phil */
    { "requestinfo",    RequestInfo},
    { "setfacemode",    SetFaceMode},
    { "setsound",       SetSound},
    { "setup",          SetUp},
    { "version",        VersionCmd },
    { "toggleextendedinfos", ToggleExtendedInfos}, /*Added: tchize*/
    { "toggleextendedtext", ToggleExtendedText},   /*Added: tchize*/
    { "asksmooth", AskSmooth},   /*Added: tchize (smoothing technologies)*/ 
    { NULL, NULL}       /* terminator (I, II & III)*/
};

/**
 * RequestInfo is sort of a meta command. There is some specific
 * request of information, but we call other functions to provide
 * that information.
 */
void RequestInfo(char *buf, int len, NewSocket *ns)
{
    char    *params=NULL, *cp;
    /* No match */
    char bigbuf[MAX_BUF];
    int slen;

    /* Set up replyinfo before we modify any of the buffers - this is used
     * if we don't find a match.
     */
    strcpy(bigbuf,"replyinfo ");
    slen = strlen(bigbuf);
    safe_strcat(bigbuf, buf, &slen, MAX_BUF);

    /* find the first space, make it null, and update the
     * params pointer.
     */
    for (cp = buf; *cp != '\0'; cp++)
        if (*cp==' ') {
            *cp = '\0';
            params = cp + 1;
            break;
        }
    if (!strcmp(buf, "image_info")) send_image_info(ns, params);
    else if (!strcmp(buf,"image_sums")) send_image_sums(ns, params);
    else if (!strcmp(buf,"skill_info")) send_skill_info(ns, params);
    else if (!strcmp(buf,"spell_paths")) send_spell_paths(ns, params);
    else Write_String_To_Socket(ns, bigbuf, len);
}

/**
 * Handles old socket format.
 */
void Handle_Oldsocket(NewSocket *ns)
{
    int stat,i;
    CommFunc    command;
    char buf[MAX_BUF],*cp;
    object ob;
    player pl;

    /* This is not the most efficient block, but keeps the code simpler -
     * we basically read a byte at a time until we get a newline, error,
     * or no more characters to read.
     */
    do {
        /* hack to disable old socket mode without creating too many conflicts */
        if (1 || ns->inbuf.len >= MAXSOCKBUF-1) {
            ns->status = Ns_Dead;
            LOG(llevDebug, "Old input socket sent too much data without newline\n");
            return;
        }
#ifdef WIN32 /* ***win32: change oldsocket read() to recv() */
                stat = recv(ns->fd, ns->inbuf.buf + ns->inbuf.len, 1,0);

        if (stat==-1 && WSAGetLastError() !=WSAEWOULDBLOCK) {
#else
        do {
            stat = read(ns->fd, ns->inbuf.buf + ns->inbuf.len, 1);
        } while ((stat<0) && (errno == EINTR));

        if (stat<0 && errno != EAGAIN && errno !=EWOULDBLOCK) {
#endif  
            LOG(llevError, "Cannot read from socket: %s\n", strerror_local(errno));
            ns->status = Ns_Dead;
            return;
        }
        if (stat == 0) return;
    } while (ns->inbuf.buf[ns->inbuf.len++]!='\n');

    ns->inbuf.buf[ns->inbuf.len]=0;

    cp = strchr(ns->inbuf.buf, ' ');
    if (cp) {
        /* Replace the space with a null, skip any more spaces */
        *cp++=0;
        while (isspace(*cp)) cp++;
    }

    /* Strip off all spaces and control characters from end of line */
    for (i=ns->inbuf.len-1; i>=0; i--) {
        if (ns->inbuf.buf[i]<=32) ns->inbuf.buf[i]=0;
        else break;
    }
    ns->inbuf.len=0;    /* reset for next read */

    /* If just a return, don't do anything */
    if (ns->inbuf.buf[0] == 0) return;
    if (!strcasecmp(ns->inbuf.buf,"quit")) {
        ns->status = Ns_Dead;
        return;
    }
    if (!strcasecmp(ns->inbuf.buf, "listen")) {
        if (cp) {
            char *buf="Socket switched to listen mode\n";

            free(ns->comment);
            ns->comment = strdup_local(cp);
            ns->old_mode = Old_Listen;
            cs_write_string(ns, buf, strlen(buf));
        } else {
            char *buf="Need to supply a comment/url to listen\n";
            cs_write_string(ns, buf, strlen(buf));
        }
        return;
    }
    if (!strcasecmp(ns->inbuf.buf, "name")) {
        char *cp1=NULL;
        if (cp) cp1= strchr(cp, ' ');
        if (cp1) {
            *cp1++ = 0;
            while (isspace(*cp1)) cp1++;
        }
        if (!cp || !cp1) {
            char *buf="Need to provide a name/password to name\n";
            cs_write_string(ns, buf, strlen(buf));
            return;
        }

        if (verify_player(cp, cp1)==0) {
            char *buf="Welcome back\n";
            free(ns->comment);
            ns->comment = strdup_local(cp);
            ns->old_mode = Old_Player;
            cs_write_string(ns, buf, strlen(buf));
        }
        else if (verify_player(cp, cp1)==2) {
            ns->password_fails++;
            if (ns->password_fails >= MAX_PASSWORD_FAILURES) {
                char *buf="You failed to log in too many times, you will now be kicked.\n";
                LOG(llevInfo, "A player connecting from %s in oldsocketmode has been dropped for password failure\n",
                    ns->host); 
                cs_write_string(ns, buf, strlen(buf));
                ns->status = Ns_Dead;
            }
            else {
                char *buf="Could not login you in.  Check your name and password.\n";
                cs_write_string(ns, buf, strlen(buf));
            }
        }       
        else {
            char *buf="Could not login you in.  Check your name and password.\n";
            cs_write_string(ns, buf, strlen(buf));
        }
        return;
    }

    command = find_oldsocket_command(ns->inbuf.buf);
    if (!command && ns->old_mode==Old_Player) {
        command = find_oldsocket_command2(ns->inbuf.buf);
    }
    if (!command) {
        snprintf(buf, sizeof(buf), "Could not find command: %s\n", ns->inbuf.buf);
        cs_write_string(ns, buf, strlen(buf));
        return;
    }

    /* This is a bit of a hack, but works.  Basically, we make some
     * fake object and player pointers and give at it.
     * This works as long as the functions we are calling don't need
     * to do anything to the object structure (ie, they are only
     * outputting information and not actually updating anything much.)
     */
    ob.contr = &pl;
    pl.ob = &ob;
    ob.type = PLAYER;
    pl.listening = 10;
    pl.socket = *ns;
    pl.outputs_count = 1;
    ob.name = ns->comment;

    command(&ob, cp);
}


/**
 * Handle client input.
 *
 * HandleClient is actually not named really well - we only get here once
 * there is input, so we don't do exception or other stuff here.
 * sock is the output socket information.  pl is the player associated
 * with this socket, null if no player (one of the init_sockets for just
 * starting a connection)
 */

void HandleClient(NewSocket *ns, player *pl)
{
    int len=0,i,cnt;
    unsigned char *data;

    /* Loop through this - maybe we have several complete packets here. */
    // limit to a few commands only, though, as to not monopolise the server
    for (cnt = 16; cnt--; ) {
        /* If it is a player, and they don't have any speed left, we
         * return, and will read in the data when they do have time.
         */
        if (pl && pl->state==ST_PLAYING && pl->ob != NULL && pl->ob->speed_left < 0) {
            return;
        }
            
        if (ns->status == Ns_Old) {
            Handle_Oldsocket(ns);
            return;
        }
        i=SockList_ReadPacket(ns->fd, &ns->inbuf, MAXSOCKBUF-1);
        /* Special hack - let the user switch to old mode if in the Ns_Add
         * phase.  Don't demand they add in the special length bytes
         */
        if (ns->status == Ns_Add) {
            if (!strncasecmp(ns->inbuf.buf,"oldsocketmode", 13)) {
                ns->status = Ns_Old;
                ns->inbuf.len=0;
                cs_write_string(ns, "Switched to old socket mode\n", 28);
                LOG(llevDebug,"Switched socket to old socket mode\n");
                return;
            }
        }

        if (i<0) {
#ifdef ESRV_DEBUG
            LOG(llevDebug,"HandleClient: Read error on connection player %s\n", (pl?pl->ob->name:"None"));
#endif
            /* Caller will take care of cleaning this up */
            ns->status =Ns_Dead;
            return;
        }
        /* Still dont have a full packet */
        if (i==0) return;

        /* First, break out beginning word.  There are at least
         * a few commands that do not have any paremeters.  If
         * we get such a command, don't worry about trying
         * to break it up.
         */
        data = (unsigned char *)strchr((char*)ns->inbuf.buf +2, ' ');
        if (data) {
            *data='\0';
            data++;
            len = ns->inbuf.len - (data - ns->inbuf.buf);
        }
        else len=0;

        ns->inbuf.buf[ns->inbuf.len]='\0';  /* Terminate buffer - useful for string data */
        for (i=0; nscommands[i].cmdname !=NULL; i++) {
            if (strcmp((char*)ns->inbuf.buf+2,nscommands[i].cmdname)==0) {
                nscommands[i].cmdproc((char*)data,len,ns);
                ns->inbuf.len=0;
                return;//D// not doing this causes random memory corruption
                goto next_packet;
            }
        }
        /* Player must be in the playing state or the flag on the
         * the command must be zero for the user to use the command -
         * otherwise, a player cam save, be in the play_again state, and
         * the map they were on gets swapped out, yet things that try to look
         * at the map causes a crash.  If the command is valid, but
         * one they can't use, we still swallow it up.
         */
        if (pl) for (i=0; plcommands[i].cmdname !=NULL; i++) {
            if (strcmp((char*)ns->inbuf.buf+2,plcommands[i].cmdname)==0) {
                if (pl->state == ST_PLAYING || !(plcommands[i].flag & 1))
                    plcommands[i].cmdproc((char*)data,len,pl);
                ns->inbuf.len=0;
                //D// not doing this causes random memory corruption
                if (plcommands[i].flag & 2)
                  goto next_packet;
                return;
            }
        }
        /* If we get here, we didn't find a valid command.  Logging
         * this might be questionable, because a broken client/malicious
         * user could certainly send a whole bunch of invalid commands.
         */
        LOG(llevDebug,"Bad command from client (%s)\n",ns->inbuf.buf+2);
    next_packet:
        ;
    }
}


/*****************************************************************************
 *
 * Low level socket looping - select calls and watchdog udp packet
 * sending.
 *
 ******************************************************************************/

#ifdef WATCHDOG
/**
 * Tell watchdog that we are still alive
 *
 * I put the function here since we should hopefully already be getting
 * all the needed include files for socket support 
 */

void watchdog(void)
{
  static int fd=-1;
  static struct sockaddr_in insock;

  if (fd==-1)
    {
      struct protoent *protoent;

      if ((protoent=getprotobyname("udp"))==NULL ||
        (fd=socket(PF_INET, SOCK_DGRAM, protoent->p_proto))==-1)
      {
        return;
      }
      insock.sin_family=AF_INET;
      insock.sin_port=htons((unsigned short)13325);
      insock.sin_addr.s_addr=inet_addr("127.0.0.1");
    }
  sendto(fd,(void *)&fd,1,0,(struct sockaddr *)&insock,sizeof(insock));
}
#endif

extern unsigned long todtick;

/** Waits for new connection */
static void block_until_new_connection(void)
{

    struct timeval Timeout;
    fd_set readfs;
    int cycles;

    LOG(llevInfo, "Waiting for connections...\n");

    cycles=1;
    do {
        /* Every minutes is a bit often for updates - especially if nothing is going
         * on.  This slows it down to every 6 minutes.
         */
        cycles++;
        if (cycles%2 == 0)
            tick_the_clock();

        FD_ZERO(&readfs);
        FD_SET((uint32)init_sockets[0].fd, &readfs);

        /* If fastclock is set, we need to seriously slow down the updates
         * to the metaserver as well as watchdog.  Do same for flush_old_maps() -
         * that is time sensitive, so there is no good reason to call it 2000 times
         * a second.
         */
        if (settings.fastclock > 0) {
#ifdef WATCHDOG
            if (cycles % 120000 == 0) {
                watchdog();
                flush_old_maps();
            }
#endif
            if (cycles == 720000) {
                metaserver_update();
                cycles=1;
            }
            Timeout.tv_sec=0;
            Timeout.tv_usec=50;
        } else {
            Timeout.tv_sec=60;
            Timeout.tv_usec=0;
            if (cycles == 7) {
                metaserver_update();
                cycles=1;
            }
            flush_old_maps();
        }
    }
    while (select(socket_info.max_filedescriptor, &readfs, NULL, NULL, &Timeout)==0);

    reset_sleep(); /* Or the game would go too fast */
}

void flush_sockets(void)
{
  player *pl;

  for (pl = first_player; pl != NULL; pl = pl->next)
    if (pl->socket.status != Ns_Dead)
      Socket_Flush (&pl->socket);
}

/**
 * This checks the sockets for input and exceptions, does the right thing.
 *
 * A bit of this code is grabbed out of socket.c
 * There are 2 lists we need to look through - init_sockets is a list
 * 
 */
void doeric_server(void)
{
    int i, pollret;
    fd_set tmp_read, tmp_exceptions, tmp_write;
    struct sockaddr_in addr;
    socklen_t addrlen=sizeof(struct sockaddr);
    player *pl, *next;

#ifdef CS_LOGSTATS
    if ((time(NULL)-cst_lst.time_start)>=CS_LOGTIME)
        write_cs_stats();
#endif

    FD_ZERO(&tmp_read);
    FD_ZERO(&tmp_write);
    FD_ZERO(&tmp_exceptions);

    for(i=0;i<socket_info.allocated_sockets;i++) {
        if (init_sockets[i].status == Ns_Dead) {
            free_newsocket(&init_sockets[i]);
            init_sockets[i].status = Ns_Avail;
            socket_info.nconns--;
        } else if (init_sockets[i].status != Ns_Avail){
            FD_SET((uint32)init_sockets[i].fd, &tmp_read);
            FD_SET((uint32)init_sockets[i].fd, &tmp_write);
            FD_SET((uint32)init_sockets[i].fd, &tmp_exceptions);
        }
    }

    /* Go through the players.  Let the loop set the next pl value,
     * since we may remove some
     */
    for (pl=first_player; pl!=NULL; ) {
        if (pl->socket.status == Ns_Dead) {
            player *npl=pl->next;

            save_player(pl->ob, 0);
            if(!QUERY_FLAG(pl->ob,FLAG_REMOVED)) {
                terminate_all_pets(pl->ob);
                remove_ob(pl->ob);
            }
            leave(pl,1);
            final_free_player(pl);
            pl=npl;
        }
        else {
            FD_SET((uint32)pl->socket.fd, &tmp_read);
            FD_SET((uint32)pl->socket.fd, &tmp_write);
            FD_SET((uint32)pl->socket.fd, &tmp_exceptions);
            pl=pl->next;
        }
    }

    if (socket_info.nconns==1 && first_player==NULL) 
        block_until_new_connection();

    /* Reset timeout each time, since some OS's will change the values on
     * the return from select.
     */
    socket_info.timeout.tv_sec = 0;
    socket_info.timeout.tv_usec = 0;

    pollret= select(socket_info.max_filedescriptor, &tmp_read, &tmp_write, 
                    &tmp_exceptions, &socket_info.timeout);

    if (pollret==-1) {
        LOG(llevError, "select failed: %s\n", strerror_local(errno));
        return;
    }

    /* We need to do some of the processing below regardless */
/*    if (!pollret) return;*/

    /* Following adds a new connection */
    if (pollret && FD_ISSET(init_sockets[0].fd, &tmp_read)) {
        int newsocknum=0;

#ifdef ESRV_DEBUG
        LOG(llevDebug,"doeric_server: New Connection\n");
#endif
        /* If this is the case, all sockets currently in used */
        if (socket_info.allocated_sockets <= socket_info.nconns) {
            init_sockets = realloc(init_sockets,sizeof(NewSocket)*(socket_info.nconns+1));
            if (!init_sockets) fatal(OUT_OF_MEMORY);
            newsocknum = socket_info.allocated_sockets;
            socket_info.allocated_sockets++;
            init_sockets[newsocknum].faces_sent_len = nrofpixmaps;
            init_sockets[newsocknum].faces_sent = malloc(nrofpixmaps*sizeof(*init_sockets[newsocknum].faces_sent));
            if (!init_sockets[newsocknum].faces_sent) fatal(OUT_OF_MEMORY);
            init_sockets[newsocknum].status = Ns_Avail;
        }
        else {
            int j;

            for (j=1; j<socket_info.allocated_sockets; j++)
                if (init_sockets[j].status == Ns_Avail) {
                    newsocknum=j;
                    break;
                }
        }
        init_sockets[newsocknum].fd=accept(init_sockets[0].fd, (struct sockaddr *)&addr, &addrlen);
        if (init_sockets[newsocknum].fd==-1) {
            LOG(llevError, "accept failed: %s\n", strerror_local(errno));
        }
        else {
            char buf[MAX_BUF];
            long ip;
            NewSocket *ns;

            ns = &init_sockets[newsocknum];

            ip = ntohl(addr.sin_addr.s_addr);
            sprintf(buf, "%ld.%ld.%ld.%ld", (ip>>24)&255, (ip>>16)&255, (ip>>8)&255, ip&255);

            if (checkbanned(NULL, buf)) {
                LOG(llevInfo, "Banned host tried to connect: [%s]\n", buf);
                close(init_sockets[newsocknum].fd);
                init_sockets[newsocknum].fd = -1;
            }
            else {
                InitConnection(ns, buf);
                socket_info.nconns++;
            }
        }
    }

    /* Check for any exceptions/input on the sockets */
    if (pollret) for(i=1;i<socket_info.allocated_sockets;i++) {
        if (init_sockets[i].status == Ns_Avail) continue;
        if (FD_ISSET(init_sockets[i].fd,&tmp_exceptions)) {
            free_newsocket(&init_sockets[i]);
            init_sockets[i].status = Ns_Avail;
            socket_info.nconns--;
            continue;
        }
        if (FD_ISSET(init_sockets[i].fd, &tmp_read)) {
            HandleClient(&init_sockets[i], NULL);
        }
        if (FD_ISSET(init_sockets[i].fd, &tmp_write)) {
            init_sockets[i].can_write=1;
        }
    }

    /* This does roughly the same thing, but for the players now */
    for (pl=first_player; pl!=NULL; pl=next) {

        next=pl->next;
        if (pl->socket.status==Ns_Dead) continue;

        if (FD_ISSET(pl->socket.fd,&tmp_write)) {
            if (!pl->socket.can_write)  {
#if 0
                LOG(llevDebug,"Player %s socket now write enabled\n", pl->ob->name);
#endif
                pl->socket.can_write=1;
                write_socket_buffer(&pl->socket);
            }
            /* if we get an error on the write_socket buffer, no reason to
             * continue on this socket.
             */
            if (pl->socket.status==Ns_Dead) continue;
        }
        else        pl->socket.can_write=0;

        if (FD_ISSET(pl->socket.fd,&tmp_exceptions)) {
            save_player(pl->ob, 0);
            if(!QUERY_FLAG(pl->ob,FLAG_REMOVED)) {
                terminate_all_pets(pl->ob);
                remove_ob(pl->ob);
            }
            leave(pl,1);
            final_free_player(pl);
        }
        else {
            HandleClient(&pl->socket, pl);
            /* If the player has left the game, then the socket status
             * will be set to this be the leave function.  We don't
             * need to call leave again, as it has already been called
             * once.
             */
            if (pl->socket.status==Ns_Dead) {
                save_player(pl->ob, 0);
                if(!QUERY_FLAG(pl->ob,FLAG_REMOVED)) {
                    terminate_all_pets(pl->ob);
                    remove_ob(pl->ob);
                }
                leave(pl,1);
                final_free_player(pl);
            } else {

                /* Update the players stats once per tick.  More efficient than
                 * sending them whenever they change, and probably just as useful
                 */
                esrv_update_stats(pl);
                if (pl->last_weight != -1 && pl->last_weight != WEIGHT(pl->ob)) {
                    esrv_update_item(UPD_WEIGHT, pl->ob, pl->ob);
                    if(pl->last_weight != WEIGHT(pl->ob))
                        LOG(llevError, "esrv_update_item(UPD_WEIGHT) did not set player weight: is %lu, should be %lu\n", (unsigned long)pl->last_weight, WEIGHT(pl->ob));
                }
                /* draw_client_map does sanity checking that map is
                 * valid, so don't do it here.
                 */
                draw_client_map(pl->ob);
                if (pl->socket.update_look) esrv_draw_look(pl->ob);
            }
        }
    }
}
Revision:	1.8
Committed:	Sun May 21 23:46:39 2006 UTC (18 years ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.7:	+8 -0 lines
Log Message:	Problem: server sends out 2 tcp packets per command (e.g. a 2-byte packet + a 10 byte packet for a small map1a command). Solution: rewrite that thing Workaround: on linux, uncork and cork again just before sleeping for the next tick, that solves the problem without hackery or rewriting it. This cuts the # of packets send by at least one half.