#ifdef HAVE_CONFIG_H
#include <config.h>
#endif


#include <sys/time.h>
#include <sys/types.h>

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

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

#include "extern.h"
#include "krb4.h"
#include "auth.h"


static KTEXT_ST cip;
static time_t local_time;

static char name[ANAME_SZ], inst[INST_SZ], realm[REALM_SZ];

static int
save_tkt(char *user, char *instance, char *realm, void *arg, 
	 int (*key_proc)(char*, char*, char*, void*, des_cblock*), KTEXT *cipp)
{
    local_time = time(0);
    memmove(&cip, *cipp, sizeof(cip));
    return -1;
}

static int
store_ticket(KTEXT cip)
{
    char *ptr;
    des_cblock session;
    char sname[SNAME_SZ];
    char sinst[INST_SZ];
    char srealm[REALM_SZ];
    unsigned char lifetime;
    unsigned char kvno;
    KTEXT_ST tkt;

    int kerror;
    
    time_t kdc_time;

    ptr = (char *) cip->dat;

    /* extract session key */
    memmove(session, ptr, 8);
    ptr += 8;

    if ((strlen(ptr) + (ptr - (char *) cip->dat)) > cip->length)
	return(INTK_BADPW);

    /* extract server's name */
    strcpy(sname,ptr);
    ptr += strlen(sname) + 1;

    if ((strlen(ptr) + (ptr - (char *) cip->dat)) > cip->length)
	return(INTK_BADPW);

    /* extract server's instance */
    strcpy(sinst, ptr);
    ptr += strlen(sinst) + 1;

    if ((strlen(ptr) + (ptr - (char *) cip->dat)) > cip->length)
	return(INTK_BADPW);

    /* extract server's realm */
    strcpy(srealm,ptr);
    ptr += strlen(srealm) + 1;

    /* extract ticket lifetime, server key version, ticket length */
    /* be sure to avoid sign extension on lifetime! */
    lifetime = (unsigned char) ptr[0];
    kvno = (unsigned char) ptr[1];
    tkt.length = (unsigned char) ptr[2];
    ptr += 3;
    
    if ((tkt.length < 0) ||
	((tkt.length + (ptr - (char *) cip->dat)) > cip->length))
	return(INTK_BADPW);

    /* extract ticket itself */
    memmove(tkt.dat, ptr, tkt.length);
    ptr += tkt.length;

    /* Here is where the time should be verified against the KDC.
     * Unfortunately everything is sent in host byte order (receiver
     * makes wrong) , and at this stage there is no way for us to know
     * which byteorder the KDC has. So we simply ignore the time,
     * there are no security risks with this, the only thing that can
     * happen is that we might receive a replayed ticket, which could
     * at most be useless.
     */
    
#if 0
    /* check KDC time stamp */
    memmove(&kdc_time, ptr, sizeof(kdc_time));
    if (swap_bytes) swap_u_long(kdc_time);

    ptr += 4;
    
    if (abs((int)(local_time - kdc_time)) > CLOCK_SKEW) {
        return(RD_AP_TIME);		/* XXX should probably be better
					   code */
    }
#endif

    /* initialize ticket cache */

    if (tf_create(TKT_FILE) != KSUCCESS)
	return(INTK_ERR);

    if (tf_put_pname(name) != KSUCCESS ||
	tf_put_pinst(inst) != KSUCCESS) {
	tf_close();
	return(INTK_ERR);
    }

    
    kerror = tf_save_cred(sname, sinst, srealm, session, lifetime, kvno,
			  &tkt, local_time);
    tf_close();

    return(kerror);
}

void kauth(char *principal, char *ticket)
{
    char *p;
    int ret;
  
    ret = kname_parse(name, inst, realm, principal);
    if(ret){
	reply(500, "Bad principal: %s.", krb_get_err_text(ret));
	return;
    }
    if(realm[0] == 0)
	krb_get_lrealm(realm, 0);

    if(ticket){
	cip.length = base64_decode(ticket, &cip.dat);
	if(cip.length == -1){
	    reply(500, "Failed to decode data.");
	    return;
	}
	ret = store_ticket(&cip);
	if(ret){
	    reply(500, "Kerberos error: %s.", krb_get_err_text(ret));
	    memset(&cip, 0, sizeof(cip));
	    return;
	}
	if(k_hasafs())
	    k_afsklog(0, 0);
	reply(200, "OK");
	return;
    }
    
    ret = krb_get_in_tkt (name, inst, realm, "krbtgt", realm, 12,
			  NULL, save_tkt, NULL);
    if(ret != INTK_BADPW){
	reply(500, "Kerberos error: %s.", krb_get_err_text(ret));
	return;
    }
    base64_encode(cip.dat, cip.length, &p);
    reply(300, "P=%s%s%s@%s T=%s", name, *inst?".":"", inst, realm, p);
    free(p);
    memset(&cip, 0, sizeof(cip));
}