ping.c

一个功能精简的TCP/IP协议栈

                    {
                        mstimeout(&mstimer, 0); /* ..refresh timer */
                        do_transmit(gfp);       /* ..transmit next packet */
                    }
                }
                else                            /* If normal pinging.. */
                {                               /* ..and timeout */
                    if (mstimeout(&mstimer, waitime))
                        do_transmit(gfp);       /* ..transmit next packet */
                }
            }
            do_receive(gfp);                    /* Check responses */
            do_poll();                          /* Poll net drivers */
            if (kbhit())                        /* If user hit a key.. */
                breakflag = getch()==0x1b;      /* ..check for ESC */
        }
        close_net(dtype);                       /* Shut down net driver */
    }
    free(testdata);                             /* Free test data memory */
    printf("ICMP echo: %lu sent, %lu received, %lu errors\n",
           txcount, rxcount, errcount);         /* Print stats */
    return(0);
}

/* Read network config file to get IP address netmask and gateway
** Return driver type, 0 if error */
WORD read_netconfig(char *fname, NODE *np)
{
    char temps[31];
    WORD dtype=0;
    BYTE b;

    if (read_cfgstr(fname, "net", netcfg, MAXNETCFG))
    {                                               /* Get IP address */
        if (!read_cfgstr(fname, "ip", temps, 30) || (np->ip=atoip(temps))==0)
            printf("No IP address\n");
        else if (!(dtype = open_net(netcfg)))       /* Open net driver */
            printf("Can't open net driver '%s'\n", netcfg);
        else
        {                                           /* Save ether address */
            memcpy(np->mac, ether_addr(dtype), MACLEN);
            b = (BYTE)(np->ip >> 24);
            if (read_cfgstr(fname, "mask", temps, 30))
                np->mask = atoip(temps);            /* Get netmask */
            else
                np->mask = b<128 ? 0xff000000L: b<192 ? 0xffff0000L:0xffffff00L;
            if (read_cfgstr(fname, "gate", temps, 30))
                np->gate = atoip(temps);            /* Get gateway IP addr */
            else
                np->gate = 0;
        }
    }
    return(dtype);
}

/* Return ptr to local node 'n' (n=0 for first), return 0 if doesn't exist
** Used by IP functions to get my netmask & gateway addresses */
NODE *locnode_n(int n)
{
    return(n==0 ? &locnode : 0);
}

/* Do next transmission cycle */
void do_transmit(GENFRAME *gfp)
{
    ICMPKT *icmp;
    BYTE *data;
    int txlen;

    if (!arped)                                     /* If not arped, send ARP */
    {
        printf("ARP ");                             /* Make packet */
        txlen = make_arp(gfp, &locnode, &remnode, ARPREQ);
    }
    else
    {
        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++;
    }
    put_frame(gfp, txlen);                          /* Transmit packet */
}

/* Check for incoming packets, send response if required */
void do_receive(GENFRAME *gfp)
{
    NODE node;
    ICMPKT *icmp;
    IPKT *ip;
    ARPKT *arp;
    BYTE *data;
    int rxlen, txlen, len;
    char temps[18];

    if ((rxlen=get_frame(gfp)) > 0)                 /* Any incoming frames? */
    {
        ip = getframe_datap(gfp);
        if (is_arp(gfp, rxlen))
        {                                           /* ARP response? */
            arp = getframe_datap(gfp);
            if (arp->op==ARPRESP && arp->sip==remip)
            {
                memcpy(remnode.mac, arp->smac, MACLEN);
                printf("OK\n");
                arped = 1;
            }
            else if (arp->op==ARPREQ && arp->dip==locnode.ip)
            {                                       /* ARP request? */
                node.ip = arp->sip;                 /* Make ARP response */
                memcpy(node.mac, arp->smac, MACLEN);
                txlen = make_arp(gfp, &locnode, &node, ARPRESP);
                put_frame(gfp, txlen);              /* Send packet */
            }
        }
        else if ((rxlen=is_ip(gfp, rxlen))!=0 &&    /* IP datagram? */
                 ip->i.dip==locnode.ip || ip->i.dip==BCASTIP)
        {
            if ((rxlen=is_icmp(ip, rxlen))!=0)      /* ICMP? */
            {
                icmp = (ICMPKT *)ip;
                if (icmp->c.type == ICREP)          /* Echo response? */
                {
                    printf("Reply from %s seq=%u len=%u ",
                           ipstr(icmp->i.sip, temps), icmp->c.seq, rxlen);
                    rxseq = icmp->c.seq;            /* Check response */
#if ASCDATA
                    data = testdata;
#else
                    data = &testdata[rxseq%datalen];
#endif
                    if (rxlen==datalen && !memcmp(icmp->data, data, rxlen))
                    {
                        printf("OK\n");
                        rxcount++;
                    }
                    else
                    {
                        printf("ERROR\n");
                        errcount++;
                    }
                }
                else if (icmp->c.type==ICREQ)       /* Echo request? */
                {
                    getip_srce(gfp, &node);
                    len = (WORD)maxi(rxlen, 0);     /* Make response */
                    txlen = make_icmp(gfp, &locnode, &node, ICREP,
                                      icmp->c.code, (WORD)len);
                    put_frame(gfp, txlen);          /* Send packet */
                }
            }
        }
    }
}

/* Poll the network interface to keep it alive */
void do_poll(void)
{
    poll_net(genframe.g.dtype);
}

/* Display usage help */
void disp_usage(void)
{
    printf("Usage:    PING [options] [IP_addr]\n");
    printf("          If no IP address given, enters server mode\n");
    printf("Options:  -c name   Config filename (default '%s')\n", cfgfile);
    printf("          -v        Verbose (debug) mode\n");
    printf("          -f        Flood mode\n");
    printf("          -l xxx    Length of ICMP data (in bytes)\n");
    printf("          -w xxx    Waiting time (in msec)\n");
    printf("Example:  PING -c test.cfg 10.1.1.1\n");
}

/* Ctrl-break handler: set flag and return */
void break_handler(int sig)
{
    breakflag = sig;
}

/* EOF */