send_to_kdc.c

早期freebsd实现

/*
 * $Source: /usr/src/kerberosIV/krb/RCS/send_to_kdc.c,v $
 * $Author: bostic $
 *
 * Copyright 1987, 1988 by the Massachusetts Institute of Technology.
 *
 * For copying and distribution information, please see the file
 * <mit-copyright.h>.
 */

#ifndef lint
static char rcsid_send_to_kdc_c[] =
"$Id: send_to_kdc.c,v 4.22 92/07/19 13:23:29 bostic Exp $";
#endif /* lint */

#include <mit-copyright.h>

#include <des.h>
#include <krb.h>
#include <prot.h>

#include <stdio.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#ifdef lint
#include <sys/uio.h>            /* struct iovec to make lint happy */
#endif /* lint */
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <strings.h>

#define S_AD_SZ sizeof(struct sockaddr_in)

extern int errno;
extern int krb_debug;

extern char *malloc(), *calloc(), *realloc();

int krb_udp_port = 0;

/* CLIENT_KRB_TIMEOUT indicates the time to wait before
 * retrying a server.  It's defined in "krb.h".
 */
static struct timeval timeout = { CLIENT_KRB_TIMEOUT, 0};
static char *prog = "send_to_kdc";
static send_recv();

/*
 * This file contains two routines, send_to_kdc() and send_recv().
 * send_recv() is a static routine used by send_to_kdc().
 */

/*
 * send_to_kdc() sends a message to the Kerberos authentication
 * server(s) in the given realm and returns the reply message.
 * The "pkt" argument points to the message to be sent to Kerberos;
 * the "rpkt" argument will be filled in with Kerberos' reply.
 * The "realm" argument indicates the realm of the Kerberos server(s)
 * to transact with.  If the realm is null, the local realm is used.
 *
 * If more than one Kerberos server is known for a given realm,
 * different servers will be queried until one of them replies.
 * Several attempts (retries) are made for each server before
 * giving up entirely.
 *
 * If an answer was received from a Kerberos host, KSUCCESS is
 * returned.  The following errors can be returned:
 *
 * SKDC_CANT    - can't get local realm
 *              - can't find "kerberos" in /etc/services database
 *              - can't open socket
 *              - can't bind socket
 *              - all ports in use
 *              - couldn't find any Kerberos host
 *
 * SKDC_RETRY   - couldn't get an answer from any Kerberos server,
 *		  after several retries
 */

send_to_kdc(pkt,rpkt,realm)
    KTEXT pkt;
    KTEXT rpkt;
    char *realm;
{
    int i, f;
    int no_host; /* was a kerberos host found? */
    int retry;
    int n_hosts;
    int retval;
    struct sockaddr_in to;
    struct hostent *host, *hostlist = NULL;
    char *cp;
    char krbhst[MAX_HSTNM];
    char lrealm[REALM_SZ];

    /*
     * If "realm" is non-null, use that, otherwise get the
     * local realm.
     */
    if (realm)
	(void) strcpy(lrealm, realm);
    else
	if (krb_get_lrealm(lrealm,0) != KSUCCESS) {
	    if (krb_debug)
		fprintf(stderr, "%s: can't get local realm\n", prog);
	    return(SKDC_CANT);
	}
    if (krb_debug)
        printf("lrealm is %s\n", lrealm);
    if (krb_udp_port == 0) {
        register struct servent *sp;
        if ((sp = getservbyname("kerberos","udp")) == 0) {
            if (krb_debug)
                fprintf(stderr, "%s: Can't get kerberos/udp service\n",
                        prog);
            return(SKDC_CANT);
        }
        krb_udp_port = sp->s_port;
        if (krb_debug)
            printf("krb_udp_port is %d\n", krb_udp_port);
    }
    bzero((char *)&to, S_AD_SZ);
    hostlist = (struct hostent *) malloc(sizeof(struct hostent));
    if (!hostlist)
        return (/*errno */SKDC_CANT);
    if ((f = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        if (krb_debug)
            fprintf(stderr,"%s: Can't open socket\n", prog);
        return(SKDC_CANT);
    }
    /* from now on, exit through rtn label for cleanup */

    no_host = 1;
    n_hosts = 0;
    for (i = 1; krb_get_krbhst(krbhst, lrealm, i) == KSUCCESS; ++i) {
        if (krb_debug) {
            printf("Getting host entry for %s...",krbhst);
            (void) fflush(stdout);
        }
        host = gethostbyname(krbhst);
        if (krb_debug) {
            printf("%s.\n",
                   host ? "Got it" : "Didn't get it");
            (void) fflush(stdout);
        }
        if (!host)
            continue;
        no_host = 0;    /* found at least one */
        n_hosts++;
        /* preserve host network address to check later
         * (would be better to preserve *all* addresses,
         * take care of that later)
         */
        hostlist = (struct hostent *)
            realloc((char *)hostlist,
                    (unsigned)
                    sizeof(struct hostent)*(n_hosts));
        if (!hostlist)
            return /*errno */SKDC_CANT;
        bcopy((char *)host, (char *)&hostlist[n_hosts-1],
              sizeof(struct hostent));
        host = &hostlist[n_hosts-1];
        cp = malloc((unsigned)host->h_length);
        if (!cp) {
            retval = /*errno */SKDC_CANT;
            goto rtn;
        }
        bcopy((char *)host->h_addr, cp, host->h_length);
/* At least Sun OS version 3.2 (or worse) and Ultrix version 2.2
   (or worse) only return one name ... */
#ifdef h_addr
        host->h_addr_list = (char **)malloc(sizeof(char *));
        if (!host->h_addr_list) {
            retval = /*errno */SKDC_CANT;
            goto rtn;
        }
#endif
        host->h_addr = cp;
        to.sin_family = host->h_addrtype;
        bcopy(host->h_addr, (char *)&to.sin_addr,
              host->h_length);
        to.sin_port = krb_udp_port;
        if (send_recv(pkt, rpkt, f, &to, hostlist)) {
            retval = KSUCCESS;
            goto rtn;
        }
        if (krb_debug) {
            printf("Timeout, error, or wrong descriptor\n");
            (void) fflush(stdout);
        }
    }
    if (no_host) {
	if (krb_debug)
	    fprintf(stderr, "%s: can't find any Kerberos host.\n",
		    prog);
        retval = SKDC_CANT;
        goto rtn;
    }
    /* retry each host in sequence */
    for (retry = 0; retry < CLIENT_KRB_RETRY; ++retry) {
        for (host = hostlist, i = 0; i < n_hosts; host++, i++) {
            to.sin_family = host->h_addrtype;
            bcopy(host->h_addr, (char *)&to.sin_addr,
                  host->h_length);
            if (send_recv(pkt, rpkt, f, &to, hostlist)) {
                retval = KSUCCESS;
                goto rtn;
            }
        }
    }
    retval = SKDC_RETRY;
rtn:
    (void) close(f);
    if (hostlist) {
        register struct hostent *hp;
        for (hp = hostlist, i = 0; i < n_hosts; hp++, i++)
#ifdef h_addr
            if (hp->h_addr_list) {
#endif
                if (hp->h_addr)
                    free(hp->h_addr);
#ifdef h_addr
                free((char *)hp->h_addr_list);
            }
#endif
        free((char *)hostlist);
    }
    return(retval);
}

/*
 * try to send out and receive message.
 * return 1 on success, 0 on failure
 */

static send_recv(pkt,rpkt,f,_to,addrs)
    KTEXT pkt;
    KTEXT rpkt;
    int f;
    struct sockaddr_in *_to;
    struct hostent *addrs;
{
    fd_set readfds;
    register struct hostent *hp;
    struct sockaddr_in from;
    int sin_size;
    int numsent;

    if (krb_debug) {
        if (_to->sin_family == AF_INET)
            printf("Sending message to %s...",
                   inet_ntoa(_to->sin_addr));
        else
            printf("Sending message...");
        (void) fflush(stdout);
    }
    if ((numsent = sendto(f,(char *)(pkt->dat), pkt->length, 0, 
			  (struct sockaddr *)_to,
                          S_AD_SZ)) != pkt->length) {
        if (krb_debug)
            printf("sent only %d/%d\n",numsent, pkt->length);
        return 0;
    }
    if (krb_debug) {
        printf("Sent\nWaiting for reply...");
        (void) fflush(stdout);
    }
    FD_ZERO(&readfds);
    FD_SET(f, &readfds);
    errno = 0;
    /* select - either recv is ready, or timeout */
    /* see if timeout or error or wrong descriptor */
    if (select(f + 1, &readfds, (fd_set *)0, (fd_set *)0, &timeout) < 1
        || !FD_ISSET(f, &readfds)) {
        if (krb_debug) {
            fprintf(stderr, "select failed: readfds=%x",
                    readfds);
            perror("");
        }
        return 0;
    }
    sin_size = sizeof(from);
    if (recvfrom(f, (char *)(rpkt->dat), sizeof(rpkt->dat), 0,
		 (struct sockaddr *)&from, &sin_size)
        < 0) {
        if (krb_debug)
            perror("recvfrom");
        return 0;
    }
    if (krb_debug) {
        printf("received packet from %s\n", inet_ntoa(from.sin_addr));
        fflush(stdout);
    }
    for (hp = addrs; hp->h_name != (char *)NULL; hp++) {
        if (!bcmp(hp->h_addr, (char *)&from.sin_addr.s_addr,
                  hp->h_length)) {
            if (krb_debug) {
                printf("Received it\n");
                (void) fflush(stdout);
            }
            return 1;
        }
        if (krb_debug)
            fprintf(stderr,
                    "packet not from %x\n",
                    hp->h_addr);
    }
    if (krb_debug)
        fprintf(stderr, "%s: received packet from wrong host! (%x)\n",
                "send_to_kdc(send_rcv)", from.sin_addr.s_addr);
    return 0;
}