np->dtype = gfp->g.dtype;    getframe_srce(gfp, np->mac);    iph = getframe_datap(gfp);    np->ip = iph->sip;}/* Get the frame driver type, destination IP and Ethernet addresses** Returned data does not include port number, netmask or gateway addr */void getip_dest(GENFRAME *gfp, NODE *np){    IPHDR *iph;    np->dtype = gfp->g.dtype;    getframe_dest(gfp, np->mac);    iph = getframe_datap(gfp);    np->ip = iph->dip;}/* Get local node data corresponding to a frame destination IP address** Data does not include port number. Return 0 if no matching local node */int getip_locdest(GENFRAME *gfp, NODE *np){    IPHDR *iph;    NODE *locp;    int ok=0;    iph = getframe_datap(gfp);    ok = (locp = findloc_ip(iph->dip)) != 0;    if (ok)        *np = *locp;    return(ok);}/* Check a remote address to see if it is on the local subnet.** If so (or no gateway), return it. If not, return the gateway IP address */LWORD gate_ip(NODE *remp, NODE *locp){    return((locp->gate==0||on_subnet(remp->ip, locp)) ? remp->ip : locp->gate);}/* Check an IP address to see if it is on a subnet, return 0 if not */int on_subnet(LWORD remip, NODE *locp){    return(((remip ^ locp->ip) & locp->mask) == 0);}/* Return ICMP data length (-1 if no data), 0 if not ICMP */int is_icmp(IPKT *ip, int len){    ICMPKT *icmp;    WORD sum;    int dlen=0;    if (ip->i.pcol==PICMP && len>=sizeof(ICMPHDR))    {        icmp = (ICMPKT *)ip;        if ((sum=csum(&icmp->c, (WORD)len)) == 0xffff)        {            swap_icmp(icmp);            dlen = len>sizeof(ICMPHDR) ? len-sizeof(ICMPHDR) : -1;        }        else            i_printf("\nICMP checksum error: %04X\n", sum);    }    return(dlen);}/* Make an ICMP packet */int make_icmp(GENFRAME *gfp, NODE *srcep, NODE *destp, BYTE type, BYTE code,    WORD dlen){    ICMPKT *icmp;    WORD len;    icmp = getframe_datap(gfp);    icmp->c.type = type;    icmp->c.code = code;    icmp->c.check = 0;    swap_icmp(icmp);    len = (WORD)(dlen + sizeof(ICMPHDR));    icmp->c.check = ~csum(&icmp->c, len);    return(make_ip(gfp, srcep, destp, PICMP, len));}/* Make ICMP 'destination unreachable' for incoming frame */int icmp_unreach(GENFRAME *gfp, NODE *srcep, NODE *destp, BYTE code){    int len;    ICMPKT *icmp;    icmp = getframe_datap(gfp);    len = ((icmp->i.vhl & 0xf) << 2) + 8;    swap_ip(gfp);    memmove(icmp->data, icmp, len);    return(make_icmp(gfp, srcep, destp, ICUNREACH, code, (WORD)len));}/* Swap byte order of ints in ICMP header */void swap_icmp(ICMPKT *icmp){    icmp->c.ident = swapw(icmp->c.ident);    icmp->c.seq = swapw(icmp->c.seq);}/* Return the maximum ICMP data size for a given frame without fragmentation */int icmp_maxdata(GENFRAME *gfp){    return(maxi(ip_maxdata(gfp)-sizeof(ICMPHDR), 0));}/* EOF */LWORD atoip(char *str){    LWORD ip=0L;    int i=4, n;    char c=1;    while (--i>=0 && c)    {        n = 0;        while ('0'<=(c=*str++)&&c<='9')         n = n*10 + c-'0';        ip += (LWORD)n << (i*8);     }      return(ip);}char *ipstr(LWORD ip, char *s){    sprintf(s, "%lu.%lu.%lu.%lu",(ip>>24)&255,(ip>>16)&255,(ip>>8)&255,ip&255);    return(s);  }/*char *ethstr(BYTE *addr, char *str){    int i;    char *s=str;    if (!memcmp(addr, bcast2, MACLEN))        strcpy(s, "----BROADCAST----");    else for (i=0; i<MACLEN; i++)        s += si_printf(s, i>0 ? ":%02x" : "%02x", *addr++);    return(str);}*/WORD buff_freelen(CBUFF *bp){    return(bp->len ? bp->len - 1 - buff_dlen(bp) : 0);}/* Return total length of data in buffer */WORD buff_dlen(CBUFF *bp){    return((WORD)((bp->in - bp->out) & (bp->len - 1)));}WORD buff_in(CBUFF *bp, BYTE *data, WORD len){    WORD in, n, n1, n2;    in = (WORD)bp->in & (bp->len-1);        /* Mask I/P ptr to buffer area */    n = minw(len, buff_freelen(bp));        /* Get max allowable length */    n1 = minw(n, (WORD)(bp->len - in));     /* Length up to end of buff */    n2 = n - n1;                            /* Length from start of buff */    if (n1 && data)                         /* If anything to copy.. */        memcpy(&bp->data[in], data, n1);    /* ..copy up to end of buffer.. */    if (n2 && data)                         /* ..and maybe also.. */        memcpy(bp->data, &data[n1], n2);    /* ..copy into start of buffer */    bp->in += n;                            /* Bump I/P pointer */    return(n);}/* Put packet onto network, given length */WORD put_net(GENFRAME *gfp, WORD len){    WORD dtype;    SNAPFRAME *sfp;        dtype = gfp->g.dtype;    len = mini(len, getframe_maxlen(gfp));  /* Truncate if too big */    gfp->g.len = len;    if (dtype&DTYPE_SNAP && len+sizeof(SNAPHDR)<=MAXFRAME)    {                                       /* If 802.3 SNAP.. */        sfp = (SNAPFRAME *)gfp->buff;       /* Make room for new header */        memmove(&sfp->s.ptype, &sfp->e.ptype, len);        len += sizeof(SNAPHDR);             /* Set for 802.3 802.2 & SNAP */        sfp->e.ptype = swapw((WORD)(len-sizeof(ETHERHDR)));        sfp->s.lsap = 0xaaaa;        sfp->s.ctrl = 3;        memset(sfp->s.oui, 0, 3);    }    if (dtype & DTYPE_PKTD)                 /* If pkt drvr, send direct */        len = DrvEthWrite(gfp->buff, len);    else if (dtype & DTYPE_ETHER)           /* If an Ethernet frame.. */    {                                       /* ..check space in pkt buffer.. */        if (buff_freelen(&txpkts) >= len+sizeof(GENHDR))            buff_in(&txpkts, (BYTE *)gfp, (WORD)(len+sizeof(GENHDR)));    }      else        len = 0;     return(len);}/* Put frame out onto the network; if sub-frame (fragment), send it as well */int put_frame(GENFRAME *gfp, int len){    int ret=0, len1, len2;    GENFRAME *sfp;    len1 = gfp->g.fragoff ? gfp->g.fragoff : len;   /* Get len of 2 fragments */    len2 = len - len1;    sfp = (GENFRAME *)&gfp->buff[gfp->g.fragoff];   /* ..and ptr to 2nd frag */    if (len1 > 0)        ret = put_net(gfp, (WORD)len1);    if (len2 > 0)        ret += put_net(sfp, (WORD)len2);    return(ret);}void do_transmit(GENFRAME *gfp){    ICMPKT *icmp;    BYTE *data;    int txlen;    //i_printf("\nARP\r");                             /* Make packet */   // txlen = make_arp(gfp, &locnode, &remnode, ARPREQ);      //icmp = getframe_datap(gfp);                 /* Send echo req */    //icmp->c.seq = ++txseq;//#if ASCDATA  //      data = testdata;                            /* ..using plain data *///#else//        data = &testdata[txseq%DATALEN];            /* ..or random *///#endif  //      memcpy(icmp->data, data, DATALEN);    //    icmp->c.ident = 1;                          /* Make packet */      //  txlen = make_icmp(gfp, &locnode, &remnode, ICREQ, 0, DATALEN);        //txcount++;   gfp->g.dtype=DTYPE_ETHER;     icmp = getframe_datap(gfp);                 /* Send echo req */   icmp->c.seq = ++txseq;   data = &testdata[txseq%DATALEN];            /* ..or random */   memcpy(icmp->data, data, DATALEN);   icmp->c.ident = 1;                          /* Make packet */   txlen = make_icmp(gfp, &locnode, &remnode, ICREQ, 0, DATALEN);   //put_frame(gfp, txlen);                          /* Transmit packet */  DrvEthWrite(gfp,txlen);   }void ping(){	WORD dtype;        GENFRAME *gfp;	LWORD remip; 	LWORD lcip; 	char *p, c, temps[18];	char r[]={"10.1.2.74"};	char l[]={"10.1.2.5"};		char rm[]={"255.255.255.255"};	char lm[]={"255.255.255.0"};		char rg[]={"255.255.255.0"};	char lg[]={"255.255.255.0"};	    	remip=atoip(r);    	lcip=atoip(l);    	remnode.ip = remip;    	locnode.ip=lcip;    	    	remip=atoip(rm);    	lcip=atoip(lm);    	remnode.mask = remip;    	locnode.mask=lcip;    	    	remip=atoip(rg);    	lcip=atoip(lg);    	remnode.gate = remip;    	locnode.gate=lcip;    	   	    	memcpy(remnode.mac, bcast, MACLEN);     /* ..as broadcast */    	memcpy(locnode.mac, bcast, MACLEN);     /* ..as broadcast */    	i_printf("IP %s", ipstr(locnode.ip, temps));        i_printf(" mask %s\n\r", ipstr(locnode.mask, temps));    	do_transmit(gfp);    	    		}