xsh_udpecho.c

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/* xsh_udpecho.c - xsh_udpecho */

#include <xinu.h>
#include <stdio.h>
#include <string.h>

extern  int atoi(char *);

/*------------------------------------------------------------------------
 * xsh_udpecho - shell command that can send a message to a remote UDP
 *          echo server and receive a reply
 *------------------------------------------------------------------------
 */
shellcmd xsh_udpecho(int nargs, char *args[])
{
    int i;          /* index into buffer        */
    int retval;         /* return value         */
    char    msg[] = "Xinu testing UDP echo"; /* message to send */
    char    inbuf[1500];        /* buffer for incoming reply    */
    int32   slot;           /* UDP slot to use      */
    int32   msglen;         /* length of outgoing message   */
    uint32  remoteip;       /* remote IP address to use */
    uint16  remport= 7;     /* remote port number to use    */
    uint16  locport = 52743;    /* local port to use        */
    int32   retries = 3;        /* number of retries        */
    int32   delay   = 500;      /* reception delay in ms    */

    /* For argument '--help', emit help about the 'udpecho' command */

    if (nargs == 2 && strncmp(args[1], "--help", 7) == 0) {
        printf("Use: %s  REMOTEIP\n\n", args[0]);
        printf("Description:\n");
        printf("\tBounce a message off a remote UDP echo server\n");
        printf("Options:\n");
        printf("\tREMOTEIP:\tIP address in dotted decimal\n");
        printf("\t--help\t display this help and exit\n");
        return 0;
    }

    /* Check for valid IP address argument */

    if (nargs != 2) {
        fprintf(stderr, "%s: invalid number of argument(s)\n", args[0]);
        fprintf(stderr, "Try '%s --help' for more information\n",
                args[0]);
        return 1;
    }

    if (dot2ip(args[1], &remoteip) == SYSERR) {
        fprintf(stderr, "%s: invalid IP address argument\r\n",
            args[0]);
        return 1;
    }
    if (nargs == 3) {
        retval = atoi(args[2]);
        if ( (retval <= 0) || (retval > 64535) ) {
            fprintf(stderr, "%s: invalid port argument\r\n",
                args[0]);
            return 1;
        }
        remport = (uint16) retval;
    }

    fprintf(stderr, "using remote port %d\n", remport);

    /* register local UDP port */

    slot = udp_register(remoteip, remport, locport);
    if (slot == SYSERR) {
        fprintf(stderr, "%s: could not reserve UDP port %d\n",
                args[0], locport);
        return 1;
    }

    /* Retry sending outgoing datagram and getting response */

    msglen = strnlen(msg, 1200);
    for (i=0; i<retries; i++) {
        retval = udp_send(slot, msg, msglen);
        if (retval == SYSERR) {
            fprintf(stderr, "%s: error sending UDP \n",
                args[0]);
            return 1;
        }

        retval = udp_recv(slot, inbuf, sizeof(inbuf), delay);
        if (retval == TIMEOUT) {
            fprintf(stderr, "%s: timeout...\n", args[0]);
            continue;
        } else if (retval == SYSERR) {
            fprintf(stderr, "%s: error from udp_recv \n",
                args[0]);
            udp_release(slot);
            return 1;
        }
        break;
    }

    udp_release(slot);
    if (retval == TIMEOUT) {
        fprintf(stderr, "%s: retry limit exceeded\n",
            args[0]);
        return 1;
    }

    /* Response received - check contents */

    if (retval != msglen) {
        fprintf(stderr, "%s: sent %d bytes and received %d\n",
            args[0], msglen, retval);
        return 1;
    }
    for (i = 0; i < msglen; i++) {
        if (msg[i] != inbuf[i]) {
            fprintf(stderr, "%s: reply differs at byte %d\n",
                args[0], i);
            return 1;
        }
    }

    printf("UDP echo test was successful\n");
    return 0;
}