raze/polymer/build/src/mmulti.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <winsock.h>
#else
#include <unistd.h>
#include <netinet/in.h>
#ifndef __BEOS__
#include <arpa/inet.h>
#endif
#ifdef __sun
#include <sys/filio.h>
#endif
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netdb.h>
#define SOCKET int
#define INVALID_HANDLE_VALUE (-1)
#define INVALID_SOCKET (-1)
#define SOCKET_ERROR (-1)
#define closesocket close
#define ioctlsocket ioctl
#define LPHOSTENT struct hostent *

#include "compat.h"
#include <sys/time.h>
static long GetTickCount(void)
{
    struct timeval tv;
    long ti;
    if (gettimeofday(&tv,NULL) < 0) return 0;
    // tv is sec.usec, GTC gives msec
    ti = tv.tv_sec * 1000;
    ti += tv.tv_usec / 1000;
    return ti;
}
#endif

#ifdef KSFORBUILD
# include "baselayer.h"
# define printf initprintf
#endif

#ifndef min
#define min(a,b) ((a)<(b)?(a):(b))
#endif

#define MAXPLAYERS 16
#define MAXPAKSIZ 256 //576


#define PAKRATE 26   //Packet rate/sec limit ... necessary?
#define SIMMIS 0     //Release:0  Test:100 Packets per 256 missed.
#define SIMLAG 0     //Release:0  Test: 10 Packets to delay receipt
static long simlagcnt[MAXPLAYERS];
static char simlagfif[MAXPLAYERS][SIMLAG+1][MAXPAKSIZ+2];
#if ((SIMMIS != 0) || (SIMLAG != 0))
#pragma message("\n\nWARNING! INTENTIONAL PACKET LOSS SIMULATION IS ENABLED!\nREMEMBER TO CHANGE SIMMIS&SIMLAG to 0 before RELEASE!\n\n")
#endif

long myconnectindex, numplayers;
long connecthead, connectpoint2[MAXPLAYERS];

static long tims, lastsendtims[MAXPLAYERS];
static char pakbuf[MAXPAKSIZ];

#define FIFSIZ 512 //16384/40 = 6min:49sec
static long ipak[MAXPLAYERS][FIFSIZ], icnt0[MAXPLAYERS];
static long opak[MAXPLAYERS][FIFSIZ], ocnt0[MAXPLAYERS], ocnt1[MAXPLAYERS];
static char pakmem[4194304]; static long pakmemi = 1;

#define NETPORT 0x5bd9
static SOCKET mysock;
static long myip, myport = NETPORT, otherip[MAXPLAYERS], otherport[MAXPLAYERS];
static long snatchip = 0, snatchport = 0, danetmode = 255, netready = 0;

/*Addfaz NatFree Start*/
int natfree; //NatFree mode flag
int nfCurrentPlayer = 0; //Current NatFree player counter. Will only talk with one player at a time
int nfFinished = 0; //Flag that determines NatFree has found all players and set the correct port numbers [normal routines can then take place]
int HeardFrom[MAXPLAYERS]; //For connecthead
int HeardFrom2[MAXPLAYERS]; //For others

int nfCheckCP (long other) //Check if target player is our current NatFree Player
{
    if (!natfree || nfFinished)
        return 1;
    else
        if (nfCurrentPlayer == other) return 1;

    return 0;
}

int nfCheckHF (long other) //function to check if we've heard from a player
{
    if (HeardFrom[other] == 1)
        return 1;
    else
        return 0;
}

void nfIncCP () //function to handle currentplayer increment
{
    if (natfree && !nfFinished)
    {
        nfCurrentPlayer++; //Increment player counter
        if (nfCurrentPlayer == myconnectindex) nfCurrentPlayer++; //Bypass my index
        if (nfCurrentPlayer >= numplayers)
        {
            nfFinished = 1; //Set NatFree finished flag. Perform non-natfree networking routines
            initprintf("natfree: all players accounted for.\n");
            return;
        }
    }
}
/*Addfaz NatFree End*/

void netuninit ()
{
    if (mysock != (SOCKET)INVALID_HANDLE_VALUE) closesocket(mysock);
#ifdef _WIN32
    WSACleanup();
#endif
}

long netinit (long portnum)
{
    LPHOSTENT lpHostEnt;
    char hostnam[256];
    struct sockaddr_in ip;
    long i;

#ifdef _WIN32
    WSADATA ws;

    if (WSAStartup(0x101,&ws) == SOCKET_ERROR) return(0);
#endif

    mysock = socket(AF_INET,SOCK_DGRAM,0); if (mysock == INVALID_SOCKET) return(0);
#ifdef __BEOS__
    i = 1; if (setsockopt(mysock,SOL_SOCKET,SO_NONBLOCK,&i,sizeof(i)) < 0) return(0);
#else
    i = 1; if (ioctlsocket(mysock,FIONBIO,(unsigned long *)&i) == SOCKET_ERROR) return(0);
#endif

    ip.sin_family = AF_INET;
    ip.sin_addr.s_addr = INADDR_ANY;
    ip.sin_port = htons(portnum);
    if (bind(mysock,(struct sockaddr *)&ip,sizeof(ip)) != SOCKET_ERROR)
    {
        myport = portnum;
        if (gethostname(hostnam,sizeof(hostnam)) != SOCKET_ERROR)
            if ((lpHostEnt = gethostbyname(hostnam)))
            {
                myip = ip.sin_addr.s_addr = *(long *)lpHostEnt->h_addr;
                printf("mmulti: This machine's IP is %s\n", inet_ntoa(ip.sin_addr));
            }
        return(1);
    }
    return(0);
}

long netsend (long other, char *dabuf, long bufsiz) //0:buffer full... can't send
{
    struct sockaddr_in ip;

    if (!otherip[other]) return(0);

    /*Addfaz NatFree Start*/
    if (natfree && !nfFinished)
    {
        if (other == connecthead && !nfCheckHF(connecthead))
            return(0); //Only greet the connecthead if we've heard from them.

        if (myconnectindex != connecthead)
        {
            if (!nfCheckCP(other) && other != connecthead)
                return(0); //Only connect to currentplayer or connecthead
            else if (!nfCheckCP(other) && !nfCheckHF(other))
                return(0);
        }
    }
    /*Addfaz NatFree End*/

    ip.sin_family = AF_INET;
    ip.sin_addr.s_addr = otherip[other];
    ip.sin_port = otherport[other];
    return(sendto(mysock,dabuf,bufsiz,0,(struct sockaddr *)&ip,sizeof(struct sockaddr_in)) != SOCKET_ERROR);
}

long netread (long *other, char *dabuf, long bufsiz) //0:no packets in buffer
{
    struct sockaddr_in ip;
    long i;

    i = sizeof(ip);
    if (recvfrom(mysock,dabuf,bufsiz,0,(struct sockaddr *)&ip,(unsigned int *)&i) == -1) return(0);
#if (SIMMIS > 0)
    if ((rand()&255) < SIMMIS) return(0);
#endif

    snatchip = (long)ip.sin_addr.s_addr; snatchport = (long)ip.sin_port;

    (*other) = myconnectindex;
    for (i=0;i<MAXPLAYERS;i++)
        if ((otherip[i] == snatchip) && (otherport[i] == snatchport))
        { (*other) = i; break; }

    /*Addfaz NatFree Start*/
    if (natfree && !nfFinished)
    {
        if (!nfCheckHF((*other))) //Check if have heard from this player already
        {
            if (otherip[nfCurrentPlayer] == snatchip) //Check IP Matches
            {
                if (!nfCheckHF(nfCurrentPlayer) && !HeardFrom2[nfCurrentPlayer])
                {
                    if (otherport[nfCurrentPlayer] != snatchport) //If Port numbers do not match
                    {
                        initprintf("natfree: port number for player %d changed from %d to %d.\n",nfCurrentPlayer,otherport[nfCurrentPlayer],snatchport);
                        otherport[nfCurrentPlayer] = snatchport; //Correct the port number
                    }
                }
                (*other) = nfCurrentPlayer; //Set pointer
                if (!nfCheckHF(nfCurrentPlayer) && myconnectindex != connecthead)
                {
                    HeardFrom[nfCurrentPlayer] = 1;
                }
            }
        }
        else
        {
            HeardFrom[i] = 1;
            HeardFrom2[i] = 1;
        }
    }
    /*Addfaz NatFree Endt*/

#if (SIMLAG > 1)
    i = simlagcnt[*other]%(SIMLAG+1);
    *(short *)&simlagfif[*other][i][0] = bufsiz; memcpy(&simlagfif[*other][i][2],dabuf,bufsiz);
    simlagcnt[*other]++; if (simlagcnt[*other] < SIMLAG+1) return(0);
    i = simlagcnt[*other]%(SIMLAG+1);
    bufsiz = *(short *)&simlagfif[*other][i][0]; memcpy(dabuf,&simlagfif[*other][i][2],bufsiz);
#endif

    return(1);
}

long isvalidipaddress (char *st)
{
    long i, bcnt, num;

    bcnt = 0; num = 0;
    for (i=0;st[i];i++)
    {
        if (st[i] == '.') { bcnt++; num = 0; continue; }
        if (st[i] == ':')
        {
            if (bcnt != 3) return(0);
            num = 0;
            for (i++;st[i];i++)
            {
                if ((st[i] >= '0') && (st[i] <= '9'))
                { num = num*10+st[i]-'0'; if (num >= 65536) return(0); }
                else return(0);
            }
            return(1);
        }
        if ((st[i] >= '0') && (st[i] <= '9'))
        { num = num*10+st[i]-'0'; if (num >= 256) return(0); }

    }
    return(bcnt == 3);
}

//---------------------------------- Obsolete variables&functions ----------------------------------
char syncstate = 0;
void setpackettimeout (long datimeoutcount, long daresendagaincount) {}
void genericmultifunction (long other, char *bufptr, long messleng, long command) {}
long getoutputcirclesize () { return(0); }
void setsocket (long newsocket) { }
void flushpackets () {}
void sendlogon () {}
void sendlogoff () {}
//--------------------------------------------------------------------------------------------------

static long crctab16[256];
static void initcrc16 ()
{
    long i, j, k, a;
    for (j=0;j<256;j++)
    {
        for (i=7,k=(j<<8),a=0;i>=0;i--,k=((k<<1)&65535))
        {
            if ((k^a)&0x8000) a = ((a<<1)&65535)^0x1021;
            else a = ((a<<1)&65535);
        }
        crctab16[j] = (a&65535);
    }
}
#define updatecrc16(crc,dat) crc = (((crc<<8)&65535)^crctab16[((((unsigned short)crc)>>8)&65535)^dat])
static unsigned short getcrc16 (char *buffer, long bufleng)
{
    long i, j;

    j = 0;
    for (i=bufleng-1;i>=0;i--) updatecrc16(j,buffer[i]);
    return((unsigned short)(j&65535));
}

void uninitmultiplayers () { netuninit(); }

long getpacket(long *, char *);
static void initmultiplayers_reset(void)
{
    long i;

    initcrc16();
    memset(icnt0,0,sizeof(icnt0));
    memset(ocnt0,0,sizeof(ocnt0));
    memset(ocnt1,0,sizeof(ocnt1));
    memset(ipak,0,sizeof(ipak));
    //memset(opak,0,sizeof(opak)); //Don't need to init opak
    //memset(pakmem,0,sizeof(pakmem)); //Don't need to init pakmem
#if (SIMLAG > 1)
    memset(simlagcnt,0,sizeof(simlagcnt));
#endif

    lastsendtims[0] = GetTickCount();
    for (i=1;i<MAXPLAYERS;i++) lastsendtims[i] = lastsendtims[0];
    numplayers = 1; myconnectindex = 0;

    memset(otherip,0,sizeof(otherip));
    for (i=0;i<MAXPLAYERS;i++) otherport[i] = htons(NETPORT);
}

// Multiplayer command line summary. Assume myconnectindex always = 0 for 192.168.1.2
//
// /n0 (mast/slav) 2 player:               3 player:
// 192.168.1.2     game /n0                game /n0:3
// 192.168.1.100   game /n0 192.168.1.2    game /n0 192.168.1.2
// 192.168.1.4                             game /n0 192.168.1.2
//
// /n1 (peer-peer) 2 player:               3 player:
// 192.168.1.2     game /n1 192.168.1.100  game /n1 192.168.1.100 192.168.1.4
// 192.168.1.100   game 192.168.1.2 /n1    game 192.168.1.2 /n1 192.168.1.4
// 192.168.1.4                             game 192.168.1.2 192.168.1.100 /n1
long initmultiplayersparms(long argc, char **argv)
{
    long i, j, daindex, portnum = NETPORT;
    char *st;

    initmultiplayers_reset();
    danetmode = 255; daindex = 0;

    // go looking for the port, if specified
    for (i=0;i<argc;i++) {
        if (argv[i][0] != '-' && argv[i][0] != '/') continue;
        if ((argv[i][1] == 'p' || argv[i][1] == 'P') && argv[i][2]) {
            char *p;
            j = strtol(argv[i]+2, &p, 10);
            if (!(*p) && j > 1024 && j<65535) portnum = j;

            printf("mmulti: Using port %ld\n", portnum);
        }
    }

    netinit(portnum);

    for (i=0;i<argc;i++)
    {
        //if (((argv[i][0] == '/') || (argv[i][0] == '-')) &&
        //    ((argv[i][1] == 'N') || (argv[i][1] == 'n')) &&
        //    ((argv[i][2] == 'E') || (argv[i][2] == 'e')) &&
        //    ((argv[i][3] == 'T') || (argv[i][3] == 't')) &&
        //     (!argv[i][4]))
        //   { foundnet = 1; continue; }
        //if (!foundnet) continue;

        if ((argv[i][0] == '-') || (argv[i][0] == '/')) {
            if ((argv[i][1] == 'N') || (argv[i][1] == 'n') || (argv[i][1] == 'I') || (argv[i][1] == 'i'))
            {
                numplayers = 2;
                if (argv[i][2] == '0')
                {
                    danetmode = 0;
                    if ((argv[i][3] == ':') && (argv[i][4] >= '0') && (argv[i][4] <= '9'))
                    {
                        numplayers = (argv[i][4]-'0');
                        if ((argv[i][5] >= '0') && (argv[i][5] <= '9')) numplayers = numplayers*10+(argv[i][5]-'0');
                        printf("mmulti: %ld-player game\n", numplayers);
                    }
                    printf("mmulti: Master-slave mode\n");
                }
                else if (argv[i][2] == '1')
                {
                    danetmode = 1;
                    myconnectindex = daindex; daindex++;
                    printf("mmulti: Peer-to-peer mode\n");
                }
                continue;
            }
            else if ((argv[i][1] == 'P') || (argv[i][1] == 'p')) continue;
        }

        st = strdup(argv[i]); if (!st) break;
        if (isvalidipaddress(st))
        {
            if ((danetmode == 1) && (daindex == myconnectindex)) daindex++;
            for (j=0;st[j];j++) {
                if (st[j] == ':')
                { otherport[daindex] = htons((unsigned short)atol(&st[j+1])); st[j] = 0; break; }
            }
            otherip[daindex] = inet_addr(st);
            printf("mmulti: Player %ld at %s:%d\n",daindex,st,ntohs(otherport[daindex]));
            daindex++;
        }
        else
        {
            LPHOSTENT lph;
            unsigned short pt = htons(NETPORT);

            for (j=0;st[j];j++)
                if (st[j] == ':')
                { pt = htons((unsigned short)atol(&st[j+1])); st[j] = 0; break; }
            if ((lph = gethostbyname(st)))
            {
                if ((danetmode == 1) && (daindex == myconnectindex)) daindex++;
                otherip[daindex] = *(long *)lph->h_addr;
                otherport[daindex] = pt;
                printf("mmulti: Player %ld at %s:%d (%s)\n",daindex,
                       inet_ntoa(*(struct in_addr *)lph->h_addr),ntohs(pt),argv[i]);
                daindex++;
            } else printf("mmulti: Failed resolving %s\n",argv[i]);
        }
        free(st);
    }
if ((danetmode == 255) && (daindex)) { numplayers = 2; danetmode = 0; } //an IP w/o /n# defaults to /n0
    if ((numplayers >= 2) && (daindex) && (!danetmode)) myconnectindex = 1;
    if (daindex > numplayers) numplayers = daindex;

    //for(i=0;i<numplayers;i++)
    //   printf("Player %d: %d.%d.%d.%d:%d\n",i,otherip[i]&255,(otherip[i]>>8)&255,(otherip[i]>>16)&255,((unsigned long)otherip[i])>>24,ntohs(otherport[i]));

    connecthead = 0;
    for (i=0;i<numplayers-1;i++) connectpoint2[i] = i+1;
    connectpoint2[numplayers-1] = -1;

    //    return (((!danetmode) && (numplayers >= 2)) || (numplayers == 2));
    return (numplayers >= 2);
}

long initmultiplayerscycle(void)
{
    long i, k;
    extern long totalclock;

#ifdef _WIN32
    Sleep(1);
#else
    usleep(1);
#endif

    getpacket(&i,0);

    tims = GetTickCount();
    if (myconnectindex == connecthead) //Player 0 only
    {
        for (i=numplayers-1;i>0;i--)
            if (!otherip[i]) break;
        if (!i) {
            nfIncCP(); //Addfaz NatFree
            netready = 1; //Player 0 is ready
            return 0;
        }
    }
    else
    {
        if (netready) return 0;
        if (tims < lastsendtims[connecthead]) lastsendtims[connecthead] = tims;
        if (tims >= lastsendtims[connecthead]+250) //1000/PAKRATE)
        {
            lastsendtims[connecthead] = tims;

            //   short crc16ofs;       //offset of crc16
            //   long icnt0;           //-1 (special packet for MMULTI.C's player collection)
            //   ...
            //   unsigned short crc16; //CRC16 of everything except crc16
            k = 2;
            *(long *)&pakbuf[k] = -1; k += 4;
            pakbuf[k++] = 0xaa;
            *(unsigned short *)&pakbuf[0] = (unsigned short)k;
            *(unsigned short *)&pakbuf[k] = getcrc16(pakbuf,k); k += 2;
            netsend(connecthead,pakbuf,k);
        }
    }

    return 1;
}

void initmultiplayers (long argc, char **argv, char damultioption, char dacomrateoption, char dapriority)
{
    long i, j, k, otims;

    if (initmultiplayersparms(argc,argv))
    {
#if 0
        //Console code seems to crash Win98 upon quitting game
        //it's not necessary and it's not portable anyway
        char tbuf[1024];
        unsigned long u;
        HANDLE hconsout;
        AllocConsole();
        SetConsoleTitle("Multiplayer status...");
        hconsout = GetStdHandle(STD_OUTPUT_HANDLE);
        otims = 0;
#endif
        while (initmultiplayerscycle())
        {
#if 0
            if ((tims < otims) || (tims > otims+100))
            {
                otims = tims;
                sprintf(tbuf,"\rWait for players (%d/%d): ",myconnectindex,numplayers);
                for (i=0;i<numplayers;i++)
                {
                    if (i == myconnectindex) { strcat(tbuf,"<me> "); continue; }
                    if (!otherip[i]) { strcat(tbuf,"?.?.?.?:? "); continue; }
                    sprintf(&tbuf[strlen(tbuf)],"%d.%d.%d.%d:%04x ",otherip[i]&255,(otherip[i]>>8)&255,(otherip[i]>>16)&255,(((unsigned long)otherip[i])>>24),otherport[i]);
                }
                WriteConsole(hconsout,tbuf,strlen(tbuf),&u,0);
            }
        }
        FreeConsole();
#else
        }
#endif
    }
    netready = 1;
}

void dosendpackets (long other) //Host to send intially, client to send to others once heard from host.
{
    long i, j, k;

    if (!otherip[other]) return;

    //Packet format:
    //   short crc16ofs;       //offset of crc16
    //   long icnt0;           //earliest unacked packet
    //   char ibits[32];       //ack status of packets icnt0<=i<icnt0+256
    //   while (short leng)    //leng: !=0 for packet, 0 for no more packets
    //   {
    //      long ocnt;         //index of following packet data
    //      char pak[leng];    //actual packet data :)
    //   }
    //   unsigned short crc16; //CRC16 of everything except crc16


    tims = GetTickCount();
    if (tims < lastsendtims[other]) lastsendtims[other] = tims;
    if (tims < lastsendtims[other]+1000/PAKRATE) return;
    lastsendtims[other] = tims;

    k = 2;
    *(long *)&pakbuf[k] = icnt0[other]; k += 4;
    memset(&pakbuf[k],0,32);
    for (i=icnt0[other];i<icnt0[other]+256;i++)
        if (ipak[other][i&(FIFSIZ-1)])
            pakbuf[((i-icnt0[other])>>3)+k] |= (1<<((i-icnt0[other])&7));
    k += 32;

    while ((ocnt0[other] < ocnt1[other]) && (!opak[other][ocnt0[other]&(FIFSIZ-1)])) ocnt0[other]++;
    for (i=ocnt0[other];i<ocnt1[other];i++)
    {
        j = *(short *)&pakmem[opak[other][i&(FIFSIZ-1)]]; if (!j) continue; //packet already acked
        if (k+6+j+4 > (long)sizeof(pakbuf)) break;

        *(unsigned short *)&pakbuf[k] = (unsigned short)j; k += 2;
        *(long *)&pakbuf[k] = i; k += 4;
        memcpy(&pakbuf[k],&pakmem[opak[other][i&(FIFSIZ-1)]+2],j); k += j;
    }
    *(unsigned short *)&pakbuf[k] = 0; k += 2;
    *(unsigned short *)&pakbuf[0] = (unsigned short)k;
    *(unsigned short *)&pakbuf[k] = getcrc16(pakbuf,k); k += 2;

    //printf("Send: "); for(i=0;i<k;i++) printf("%02x ",pakbuf[i]); printf("\n");

    /*Addfaz NatFree Start*/
    if (nfCheckCP(other) || !natfree) //Clients only if heard from host
        netsend(other,pakbuf,k);
    /*Addfaz NatFree End*/
}

void sendpacket (long other, char *bufptr, long messleng)
{
    long i, j;

    if (numplayers < 2) return;

    if (pakmemi+messleng+2 > (long)sizeof(pakmem)) pakmemi = 1;
    opak[other][ocnt1[other]&(FIFSIZ-1)] = pakmemi;
    *(short *)&pakmem[pakmemi] = messleng;
    memcpy(&pakmem[pakmemi+2],bufptr,messleng); pakmemi += messleng+2;
    ocnt1[other]++;

    //printf("Send: "); for(i=0;i<messleng;i++) printf("%02x ",bufptr[i]); printf("\n");

    dosendpackets(other);
}

//passing bufptr == 0 enables receive&sending raw packets but does not return any received packets
//(used as hack for player collection)
long getpacket (long *retother, char *bufptr)
{
    long i, j, k, ic0, crc16ofs, messleng, other;

    if (numplayers < 2) return(0);

    if (netready)
    {
        for (i=connecthead;i>=0;i=connectpoint2[i])
        {
            if (i != myconnectindex) dosendpackets(i);
            if ((!danetmode) && (myconnectindex != connecthead)) break; //slaves in M/S mode only send to master
        }
    }

    while (netread(&other,pakbuf,sizeof(pakbuf)))
    {
        //Packet format:
        //   short crc16ofs;       //offset of crc16
        //   long icnt0;           //earliest unacked packet
        //   char ibits[32];       //ack status of packets icnt0<=i<icnt0+256
        //   while (short leng)    //leng: !=0 for packet, 0 for no more packets
        //   {
        //      long ocnt;         //index of following packet data
        //      char pak[leng];    //actual packet data :)
        //   }
        //   unsigned short crc16; //CRC16 of everything except crc16
        k = 0;
        crc16ofs = (long)(*(unsigned short *)&pakbuf[k]); k += 2;

        //printf("Recv: "); for(i=0;i<crc16ofs+2;i++) printf("%02x ",pakbuf[i]); printf("\n");

        if ((crc16ofs+2 <= (long)sizeof(pakbuf)) && (getcrc16(pakbuf,crc16ofs) == (*(unsigned short *)&pakbuf[crc16ofs])))
        {
            ic0 = *(long *)&pakbuf[k]; k += 4;
            if (ic0 == -1)
            {
                //Slave sends 0xaa to Master at initmultiplayers() and waits for 0xab response
                //Master responds to slave with 0xab whenever it receives a 0xaa - even if during game!
                if ((pakbuf[k] == 0xaa) && (myconnectindex == connecthead))
                {
                    for (other=1;other<numplayers;other++)
                    {
                        //Only send to others asking for a response
                        if ((otherip[other]) && ((otherip[other] != snatchip) || (otherport[other] != snatchport))) continue;
                        otherip[other] = snatchip;
                        otherport[other] = snatchport;

                        //   short crc16ofs;       //offset of crc16
                        //   long icnt0;           //-1 (special packet for MMULTI.C's player collection)
                        //   ...
                        //   unsigned short crc16; //CRC16 of everything except crc16
                        k = 2;
                        *(long *)&pakbuf[k] = -1; k += 4;
                        pakbuf[k++] = 0xab;
                        pakbuf[k++] = (char)other;
                        pakbuf[k++] = (char)numplayers;
                        *(unsigned short *)&pakbuf[0] = (unsigned short)k;
                        *(unsigned short *)&pakbuf[k] = getcrc16(pakbuf,k); k += 2;

                        /*Addfaz NatFree Start*/
                        if (natfree && !nfCheckHF(other))
                        {
                            initprintf("natfree: heard from player %d\n", other);
                            HeardFrom[other] = 1;
                            HeardFrom2[other] = 1;
                            nfIncCP();
                        }
                        /*Addfaz NatFree End*/

                        netsend(other,pakbuf,k);
                        break;
                    }
                }
                else if ((pakbuf[k] == 0xab) && (myconnectindex != connecthead))
                {
                    if (((unsigned long)pakbuf[k+1] < (unsigned long)pakbuf[k+2]) &&
                            ((unsigned long)pakbuf[k+2] < (unsigned long)MAXPLAYERS))
                    {
                        myconnectindex = (long)pakbuf[k+1];
                        numplayers = (long)pakbuf[k+2];

                        connecthead = 0;
                        for (i=0;i<numplayers-1;i++) connectpoint2[i] = i+1;
                        connectpoint2[numplayers-1] = -1;

                        otherip[connecthead] = snatchip;
                        otherport[connecthead] = snatchport;
                        netready = 1;

                        /*Addfaz NatFree Start*/
                        if (natfree)
                        {
                            initprintf("natfree: heard from player %d (head).\n", connecthead);
                            HeardFrom[connecthead] = 1;
                            HeardFrom2[connecthead] = 1;
                            nfIncCP();
                        }
                        /*Addfaz NatFree End*/
                    }
                }
            }
            else
            {
                if (ocnt0[other] < ic0) ocnt0[other] = ic0;
                for (i=ic0;i<min(ic0+256,ocnt1[other]);i++)
                    if (pakbuf[((i-ic0)>>3)+k]&(1<<((i-ic0)&7)))
                        opak[other][i&(FIFSIZ-1)] = 0;
                k += 32;

                messleng = (long)(*(unsigned short *)&pakbuf[k]); k += 2;
                while (messleng)
                {
                    j = *(long *)&pakbuf[k]; k += 4;
                    if ((j >= icnt0[other]) && (!ipak[other][j&(FIFSIZ-1)]))
                    {
                        if (pakmemi+messleng+2 > (long)sizeof(pakmem)) pakmemi = 1;
                        ipak[other][j&(FIFSIZ-1)] = pakmemi;
                        *(short *)&pakmem[pakmemi] = messleng;
                        memcpy(&pakmem[pakmemi+2],&pakbuf[k],messleng); pakmemi += messleng+2;
                    }
                    k += messleng;
                    messleng = (long)(*(unsigned short *)&pakbuf[k]); k += 2;
                }
            }
        }
    }

    //Return next valid packet from any player
    if (!bufptr) return(0);
    for (i=connecthead;i>=0;i=connectpoint2[i])
    {
        if (i != myconnectindex)
        {
            j = ipak[i][icnt0[i]&(FIFSIZ-1)];
            if (j)
            {
                messleng = *(short *)&pakmem[j]; memcpy(bufptr,&pakmem[j+2],messleng);
                *retother = i; ipak[i][icnt0[i]&(FIFSIZ-1)] = 0; icnt0[i]++;
                //printf("Recv: "); for(i=0;i<messleng;i++) printf("%02x ",bufptr[i]); printf("\n");

                /*Addfaz NatFree Start*/
                if (natfree && !HeardFrom2[nfCurrentPlayer] && i == nfCurrentPlayer)
                {
                    initprintf("natfree: heard from player %d.\n", i);
                    HeardFrom2[nfCurrentPlayer] = 1;
                    HeardFrom[nfCurrentPlayer] = 1;
                    nfIncCP();
                }
                /*Addfaz NatFree End*/

                return(messleng);
            }
        }
        if ((!danetmode) && (myconnectindex != connecthead)) break; //slaves in M/S mode only send to master
    }

    return(0);
}

char tempbuf[512],ipaddr[32];

const char *getexternaladdress(void)
{
    int sockfd, bytes_sent, i=0, j=0;
    struct sockaddr_in dest_addr;
    struct hostent *h;
    char *host = "checkip.dyndns.org";
    char *req = "GET / HTTP/1.0\r\n\r\n";

    if (ipaddr[0])
        return(ipaddr);

#ifdef _WIN32
    {
        WSADATA ws;

        if (WSAStartup(0x101,&ws) == SOCKET_ERROR)  {
            initprintf("mmulti: Winsock error in getexternaladdress() (%d)\n",errno);
            return(0);
        }
    }
#endif

    if ((h=gethostbyname(host)) == NULL) {
        initprintf("mmulti: gethostbyname() error in getexternaladdress() (%d)\n",h_errno);
        return(0);
    }

    dest_addr.sin_addr.s_addr = ((struct in_addr *)(h->h_addr))->s_addr;
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_port = htons(8245);

    memset(&(dest_addr.sin_zero), '\0', 8);

    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if (sockfd == SOCKET_ERROR) {
        initprintf("mmulti: socket() error in getexternaladdress() (%d)\n",errno);
        return(0);
    }

    if (connect(sockfd, (struct sockaddr *)&dest_addr, sizeof(struct sockaddr)) == SOCKET_ERROR) {
        initprintf("mmulti: connect() error in getexternaladdress() (%d)\n",errno);
        return(0);
    }

    bytes_sent = send(sockfd, req, strlen(req), 0);
    if (bytes_sent == SOCKET_ERROR) {
        initprintf("mmulti: send() error in getexternaladdress() (%d)\n",errno);
        return(0);
    }

    //    initprintf("sent %d bytes\n",bytes_sent);
    recv(sockfd, (char *)&tempbuf, sizeof(tempbuf), 0);
    closesocket(sockfd);

#ifdef _WIN32
    WSACleanup();
#endif

    for (i=0;(unsigned)i<strlen(tempbuf);i++)
    {
        if (isdigit(tempbuf[i]) && (isdigit(tempbuf[i+1]) || (tempbuf[i+1] == '.')) && (isdigit(tempbuf[i+2]) || (tempbuf[i+2] == '.')) && (isdigit(tempbuf[i+3]) || (tempbuf[i+3] == '.')))
        {
            while (isdigit(tempbuf[i]) || (tempbuf[i] == '.'))
            {
                ipaddr[j] = tempbuf[i];
                i++, j++;
            }
            ipaddr[j] = '\0';
            break;
        }
    }
    return(ipaddr);
}