/*
 * $Source: /afs/sipb.mit.edu/project/sipb-athena/repository/src/kerberos/lib/krb/send_to_kdc.c,v $
 * $Author: svalente $
 *
 * 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 1.8 1997/01/26 04:01:58 svalente Exp $";
#endif /* lint */

#include <mit-copyright.h>

#include <krb.h>
#include <krbports.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 <string.h>
#include <stdlib.h>
#ifndef NO_UNISTD_H
#include <unistd.h>
#endif

#define S_AD_SZ sizeof(struct sockaddr_in)

extern int errno;
extern int krb_debug;

int krb4_udp_port = 0;
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;
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
 */

int
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;
    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,1)) {
	    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 (krb4_udp_port == 0) {
        register struct servent *sp;
        if (sp = getservbyname("kerberos4","udp"))
	    krb4_udp_port = sp->s_port;
	else
	    krb4_udp_port = htons(KERBEROS4_PORT); /* kerberos/udp */
        if (krb_debug)
            printf("krb4_udp_port is %d\n", ntohs(krb4_udp_port));
    }
    if (krb_udp_port == 0) {
        register struct servent *sp;
        if (sp = getservbyname("kerberos","udp"))
	    krb_udp_port = sp->s_port;
	else
	    krb_udp_port = htons(KERBEROS_PORT); /* kerberos/udp */
        if (krb_debug)
            printf("krb_udp_port is %d\n", ntohs(krb_udp_port));
    }
    memset((char *)&to, 0, S_AD_SZ);
    hostlist = (struct hostent *) malloc(sizeof(struct hostent));
    if (!hostlist)
        return (/*errno */SKDC_CANT);
    hostlist->h_name = 0;	/* so it gets properly freed at "rtn" */
    
    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;
    /* get an initial allocation */
    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+1));
        if (!hostlist)
            return /*errno */SKDC_CANT;
        memcpy((char *)&hostlist[n_hosts-1], (char *)host, 
	       sizeof(struct hostent));
        host = &hostlist[n_hosts-1];
        cp = malloc((unsigned)host->h_length);
        if (!cp) {
            retval = /*errno */SKDC_CANT;
            goto rtn;
        }
        memcpy(cp, (char *)host->h_addr, host->h_length);
/* At least Sun OS version 3.2 (or worse) and Ultrix version 2.2
   (or worse) only return one name ... */
#if !(defined(ULTRIX022) || (defined(SunOS) && SunOS < 40))
        host->h_addr_list = (char **)malloc(sizeof(char *));
        if (!host->h_addr_list) {
            retval = /*errno */SKDC_CANT;
            goto rtn;
        }
#endif /* ULTRIX022 || SunOS */
        host->h_addr = cp;
        memset((char *)&hostlist[n_hosts], 0,
              sizeof(struct hostent));
        to.sin_family = host->h_addrtype;
        memcpy((char *)&to.sin_addr, host->h_addr, 
	       host->h_length);
        to.sin_port = krb4_udp_port;
        if (send_recv(pkt, rpkt, f, &to, hostlist)) {
            retval = KSUCCESS;
            goto rtn;
        }
	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; host->h_name != (char *)NULL; host++) {
            to.sin_family = host->h_addrtype;
            memcpy((char *)&to.sin_addr, host->h_addr, 
		   host->h_length);
	    to.sin_port = krb4_udp_port;
            if (send_recv(pkt, rpkt, f, &to, hostlist)) {
                retval = KSUCCESS;
                goto rtn;
            }
	    to.sin_port = krb_udp_port;
	    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; hp->h_name; hp++)
#if !(defined(ULTRIX022) || (defined(SunOS) && SunOS < 40))
            if (hp->h_addr_list) {
#endif /* ULTRIX022 || SunOS */
                if (hp->h_addr)
                    free(hp->h_addr);
#if !(defined(ULTRIX022) || (defined(SunOS) && SunOS < 40))
                free((char *)hp->h_addr_list);
            }
#endif /* ULTRIX022 || SunOS */
        free((char *)hostlist);
    }
    return(retval);
}

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

static int 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 numsent;
    size_t sin_size;

    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);
    }
    /* On BSD systems, a connected UDP socket will get connection
       refused and net unreachable errors while an unconnected
       socket will time out, so use connect, send instead of sendto.
       The connect here may return an error if the destination host
       is known to be unreachable. */
#ifdef linux
    numsent = sendto(f,(char *)(pkt->dat), pkt->length, 0,
			  (struct sockaddr *)_to, S_AD_SZ);
#else
    if (connect(f, (struct sockaddr *) _to, S_AD_SZ) < 0)
        return 0;
    numsent = send(f,(char *)(pkt->dat), pkt->length, 0);
#endif

    if (numsent < 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 */
    timeout.tv_sec = CLIENT_KRB_TIMEOUT;
    timeout.tv_usec = 0;
    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 (!memcmp(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;
}