dns.c

完整的Bell实验室的嵌入式文件系统TFS

/* dns.c:
 *  Support a basic DNS query.
 *  NOT READY YET!!!
 *
 *  General notice:
 *  This code is part of a boot-monitor package developed as a generic base
 *  platform for embedded system designs.  As such, it is likely to be
 *  distributed to various projects beyond the control of the original
 *  author.  Please notify the author of any enhancements made or bugs found
 *  so that all may benefit from the changes.  In addition, notification back
 *  to the author will allow the new user to pick up changes that may have
 *  been made by other users after this version of the code was distributed.
 *
 *  Note1: the majority of this code was edited with 4-space tabs.
 *  Note2: as more and more contributions are accepted, the term "author"
 *         is becoming a mis-representation of credit.
 *
 *  Original author:    Ed Sutter
 *  Email:              [e-mail]
 *  Phone:              908-582-2351
 */
#include "config.h"
#if INCLUDE_DNSQUERY
#include "endian.h"
#include "genlib.h"
#include "ether.h"
#include "stddefs.h"
#include "cli.h"

char *DnsHelp[] = {
    "DNS query",
    "-[c:d:f:v:] {operation} [args]",
    "Options...",
    " -c {#}    echo count",
    " -d {#}    delta (hours) relative to GMT",
    " -f {x|d}  hex or decimal output (default is ascii)",
    " -r        check server resolution",
    " -v {var}  load result in shellvar 'var'",
    "Operations...",
    " time {IP}",
    " echo {IP}",
    "Notes...",
    " If '.ns' is appended to time, then time is non-standard.",
    " The 'dfrv' options are used by icmp time, option 'c' is used by echo.",
    0,
};

int
Dns(int argc,char *argv[])
{
    int     timestamp, hour, min, sec, opt, gmt_delta, timeout, count;
    char    *varname, format, *nonstandard, *operation, *ipadd;
    uchar   binip[8], binenet[8], buf[32];
    ushort  seqno;

    gmt_delta = 0;
    count = 1;
    varname = (char *)0;
    format = 'a';
    nonstandard = "";
    CheckSrvrResolution = 0;

    while ((opt=getopt(argc,argv,"c:d:f:rv:")) != -1) {
        switch(opt) {
        case 'c':   /* count used by ping */
            count = strtol(optarg,(char **)0,0);
            break;
        case 'd':   /* difference between this time zone and Greenwich */
            gmt_delta = strtol(optarg,(char **)0,0);
            break;
        case 'f':
            format = *optarg;
            break;
        case 'r':
            CheckSrvrResolution = 1;
            break;
        case 'v':
            varname = optarg;
            break;
        default:
            return(CMD_PARAM_ERROR);
        }
    }

    if (argc == optind)
        return(-1);

    operation = argv[optind];
    ipadd = argv[optind+1];
    
    /* If time or echo, do the common up-front stuff here... */
    if (!strcmp(operation,"time") || !strcmp(operation,"echo")) {
        if (argc != optind + 2)
            return(CMD_PARAM_ERROR);

        /* Convert IP address to binary: */
        if (IpToBin(ipadd,binip) < 0)
            return(CMD_SUCCESS);
    }

    if (!strcmp(operation, "time")) {

        /* Get the ethernet address for the IP: */
        if (!ArpEther(binip,binenet,0)) {
            printf("ARP failed for %s\n",ipadd);
            return(CMD_FAILURE);
        }

        ICMPTimeStamp = INVALID_TIMESTAMP;
        SendICMPRequest(ICMP_TIMEREQUEST,binip,binenet,0,0);

        /* Timeout waiting for timestamp after waiting about 2 seconds. */
        timeout = LoopsPerSecond * 2;
        while(timeout > 0) {
            pollethernet();
            timeout--;
            if (ICMPTimeStamp != INVALID_TIMESTAMP)
                break;
        }
        if (timeout == 0) {
            printf("No response\n");
            return(CMD_FAILURE);
        }

        if (ICMPTimeStamp & NONSTANDARD_TIMESTAMP) {
            ICMPTimeStamp &= ~NONSTANDARD_TIMESTAMP;
            nonstandard = ".ns";
        }

        if (format == 'a') {
            timestamp = ICMPTimeStamp + (gmt_delta*MSECS_PER_HOUR);
            hour = timestamp/MSECS_PER_HOUR;
            timestamp -= hour*MSECS_PER_HOUR;
            min = timestamp/MSECS_PER_MINUTE;
            timestamp -= min*MSECS_PER_MINUTE;
            sec = timestamp/MSECS_PER_SECOND;
            timestamp -= sec*MSECS_PER_SECOND;
            sprintf(buf,"%02d:%02d:%02d.%03d%s",hour,min,sec,timestamp,
                nonstandard);
        }
        else if (format == 'x')
            sprintf(buf,"0x%lx%s",ICMPTimeStamp,nonstandard);
        else if (format == 'd')
            sprintf(buf,"%ld%s",ICMPTimeStamp,nonstandard);
        else
            return(CMD_PARAM_ERROR);
        if (varname)
            setenv(varname,buf);
        else if (!CheckSrvrResolution)
            printf("%s\n",buf);
        CheckSrvrResolution = 0;
    }
    else if (!strcmp(operation, "echo")) {
        seqno = 0;
        while (count-- > 0) {

            /* Is this a self-ping? */
            if (memcmp(binip,BinIpAddr,4) == 0) {
                printf("Yes, I am alive!\n");
                break;
            }
            /* Get the ethernet address for the IP: */
            if (!ArpEther(binip,binenet,0)) {
                printf("ARP failed for %s\n",ipadd);
                continue;
            }

            ICMPEchoReplyId = 0;
            SendICMPRequest(ICMP_ECHOREQUEST,binip,binenet,0,seqno);

            /* Timeout waiting for reply after waiting about 2 secs. */
            timeout = LoopsPerSecond * 2;
            while(timeout > 0) {
                pollethernet();
                timeout--;
                if (ICMPEchoReplyId == ICMP_ECHO_ID)
                    break;
            }
            if (timeout == 0)
                printf("no answer from %s\n",ipadd);
            else {
                printf("%s is alive",ipadd);
                if (count) {
                    printf(" icmp_seq=%d",ICMPSeqNoRcvd);
                    timeout = LoopsPerSecond;
                    while(timeout-- > 0)
                        pollethernet();
                    seqno++;
                }
                printf("\n");
            }
        }
    }
    else
        printf("Unrecognized ICMP op: %s\n",operation);
    return(CMD_SUCCESS);
}

int
processDNS(struct ether_header *ehdr,ushort size)
{
    struct  ip *ipp;
    struct  icmp_hdr *icmpp;
    int len, i;

    ipp = (struct ip *)(ehdr + 1);

    /* Compute size of ICMP message (IP len - size of IP header): */
    len = ipp->ip_len - ((ipp->ip_vhl & 0x0f) * 4);

    icmpp = (struct icmp_hdr *)((char *)ipp+IP_HLEN(ipp));
    if (icmpp->type == ICMP_ECHOREQUEST) {      /* 3rdEd Comer pg 127 */
        SendEchoResp(ehdr);
        return(0);
    }
    else if (icmpp->type == ICMP_ECHOREPLY) {
        struct icmp_echo_hdr *icmpecho;

        icmpecho = (struct icmp_echo_hdr *)icmpp;
        ICMPEchoReplyId = ecs(icmpecho->id);
        ICMPSeqNoRcvd = ecs(icmpecho->seq);
    }
    else if (icmpp->type == ICMP_DESTUNREACHABLE) { /* 3rdEd Comer pg 129 */
        if (EtherVerbose & SHOW_INCOMING) {
            i = icmpp->code;
            if ((i > 5) || (i < 0))
                i = 6;
            printf("  ICMP: %s (code=%d)\n",
                IcmpDestUnreachableCode[i],icmpp->code);
        }
        return(0);
    }
    else if (icmpp->type == ICMP_TIMEREPLY) {
        struct icmp_time_hdr *icmptime;
        ulong orig, recv, xmit;

        icmptime = (struct icmp_time_hdr *)icmpp;
        memcpy((char *)&orig,(char *)&icmptime->orig,4);
        memcpy((char *)&recv,(char *)&icmptime->recv,4);
        memcpy((char *)&xmit,(char *)&icmptime->xmit,4);

        ICMPSeqNoRcvd = icmptime->seq;
        if (EtherVerbose & SHOW_INCOMING) {
            printf("    ICMP_TIMEREPLY: orig=0x%lx,recv=0x%lx,xmit=0x%lx\n",
                orig,recv,xmit);
        }
        if (CheckSrvrResolution) {
            static int ICMPTimeStampTbl[20];
    
            if (icmptime->seq < 20) {
                ICMPTimeStampTbl[icmptime->seq] = xmit;
                SendICMPRequest(ICMP_TIMEREQUEST,(uchar *)&ipp->ip_src,
                    (uchar *)&ehdr->ether_shost,0,icmptime->seq+1);
            } else {
                
                printf("TS00: %d\n",ICMPTimeStampTbl[0]);
                for(i=1;i<20;i++) {
                    printf("TS%02d: %d (dlta=%d)\n",i,
                        ICMPTimeStampTbl[i],
                        ICMPTimeStampTbl[i]-ICMPTimeStampTbl[i-1]);
                }
                ICMPTimeStamp = xmit;
            }
        }
        else {
            ICMPTimeStamp = xmit;
        }
    }
    else {
        if (EtherVerbose & SHOW_INCOMING) {
            printf("    ICMPTYPE=%d\n",icmpp->type);
        }
        return(-1);
    }
    return(0);
}

/* SendDNSQuery():
 */
int
SendDNSQuery(ulong addr,char *tftpsrvr,char *mode, char *hostfile,char *tfsfile,
    char *tfsflags,char *tfsinfo)
{
    int     done;
    char    buf[32];
    uchar   binip[8], binenet[8], *enetaddr;

    setenv("TFTPGET",0);

    /* Convert IP address to binary: */
    if (IpToBin(tftpsrvr,binip) < 0)
        return(0);


    /* Get the ethernet address for the IP: */
    /* Give ARP the same verbosity (if any) set up for TFTP: */
    if (EtherVerbose & SHOW_TFTP)
        EtherVerbose |= SHOW_ARP;
    enetaddr = ArpEther(binip,binenet,0);
    EtherVerbose &= ~SHOW_ARP;
    if (!enetaddr) {
        printf("ARP failed for %s\n",tftpsrvr);
        return(0);
    }

    /* Initialize the retransmission delay calculator: */
    RetransmitDelay(DELAY_INIT_TFTP);

    printf("Retrieving %s from %s...",hostfile,tftpsrvr);
    if (EtherVerbose & SHOW_TFTP)
        printf("\n");

    /* Send the TFTP RRQ to initiate the transfer. */
    if (SendTFTPRRQ(binip,binenet,hostfile,mode,(uchar *)addr) < 0) {
        printf("RRQ failed\n");
        return(0);
    }

    /* Wait for TftpState to indicate that the transaction has completed... */
    done = 0;
    while(!done) {
        pollethernet();
        switch(TftpState) {
            case TFTPIDLE:
                printf(" %d bytes",TftpCount);
                done = 1;
                break;
            case TFTPERROR:
                printf(" host error: %s\n",TftpErrString);
                done = 2;
                break;
            case TFTPTIMEOUT:
                printf(" timing out (%d bytes rcvd)\n",TftpCount);
                done = 2;
                break;
            default:
                break;
        }
    }
    if (done == 2)
        return(0);

    if (tfsfile) {
        int err, filesize;

        filesize = TftpCount - TftpChopCount;
        printf("\nAdding %s (size=%d) to TFS...",tfsfile,filesize);
        err = tfsadd(tfsfile,tfsinfo,tfsflags,(uchar *)addr,filesize);
        if (err != TFS_OKAY)
            printf("%s: %s\n",tfsfile,(char *)tfsctrl(TFS_ERRMSG,err,0));
    }
    printf("\n");
    sprintf(buf,"%d",TftpCount);
    setenv("TFTPGET",buf);
    return(TftpCount);
}

#endif