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/*
* lib/krb5/os/sendto_kdc.c
*
* Copyright 1990,1991 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* Send packet to KDC for realm; wait for response, retransmitting
* as necessary.
*/
#define NEED_SOCKETS
#define NEED_LOWLEVEL_IO
#include "k5-int.h"
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
#include "os-proto.h"
#ifdef _AIX
#include <sys/select.h>
#endif
/*
* send the formatted request 'message' to a KDC for realm 'realm' and
* return the response (if any) in 'reply'.
*
* If the message is sent and a response is received, 0 is returned,
* otherwise an error code is returned.
*
* The storage for 'reply' is allocated and should be freed by the caller
* when finished.
*/
krb5_error_code
krb5_sendto_kdc (context, message, realm, reply, use_master)
krb5_context context;
const krb5_data * message;
const krb5_data * realm;
krb5_data * reply;
int use_master;
{
int timeout, host, i;
int sent, nready;
krb5_error_code retval;
SOCKET *socklist;
fd_set readable;
struct timeval waitlen;
int cc;
struct addrlist addrs;
/*
* find KDC location(s) for realm
*/
if ((retval = krb5_locate_kdc(context, realm, &addrs, use_master)))
return retval;
if (addrs.naddrs == 0)
return (use_master ? KRB5_KDC_UNREACH : KRB5_REALM_UNKNOWN);
socklist = (SOCKET *)malloc(addrs.naddrs * sizeof(SOCKET));
if (socklist == NULL) {
krb5int_free_addrlist (&addrs);
return ENOMEM;
}
for (i = 0; i < addrs.naddrs; i++)
socklist[i] = INVALID_SOCKET;
if (!(reply->data = malloc(krb5_max_dgram_size))) {
for (i = 0; i < addrs.naddrs; i++)
krb5_xfree (addrs.addrs[i]);
krb5int_free_addrlist (&addrs);
krb5_xfree(socklist);
return ENOMEM;
}
reply->length = krb5_max_dgram_size;
#if 0
/*
* Not needed for Windows, since it's done by the DLL
* initialization. XXX What about for the Macintosh?
*
* See below for commented out SOCKET_CLEANUP()
*/
if (SOCKET_INITIALIZE()) { /* PC needs this for some tcp/ip stacks */
krb5int_free_addrlist (&addrs);
krb5_xfree(socklist);
free(reply->data);
return SOCKET_ERRNO;
}
#endif
/*
* do exponential backoff.
*/
for (timeout = krb5_skdc_timeout_1; timeout < krb5_max_skdc_timeout;
timeout <<= krb5_skdc_timeout_shift) {
sent = 0;
for (host = 0; host < addrs.naddrs; host++) {
/* send to the host, wait timeout seconds for a response,
then move on. */
/* cache some sockets for each host */
if (socklist[host] == INVALID_SOCKET) {
/* XXX 4.2/4.3BSD has PF_xxx = AF_xxx, so the socket
creation here will work properly... */
/*
* From socket(2):
*
* The protocol specifies a particular protocol to be
* used with the socket. Normally only a single
* protocol exists to support a particular socket type
* within a given protocol family.
*/
socklist[host] = socket(addrs.addrs[host]->sa_family,
SOCK_DGRAM, 0);
if (socklist[host] == INVALID_SOCKET)
continue; /* try other hosts */
/* have a socket to send/recv from */
/* 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, recv instead of
sendto, recvfrom. The connect here may return an error if
the destination host is known to be unreachable. */
if (connect(socklist[host],
addrs.addrs[host], socklen(addrs.addrs[host])) == SOCKET_ERROR)
continue;
}
if (send(socklist[host],
message->data, (int) message->length, 0)
!= message->length)
continue;
retry:
waitlen.tv_usec = 0;
waitlen.tv_sec = timeout;
FD_ZERO(&readable);
FD_SET(socklist[host], &readable);
if ((nready = select(SOCKET_NFDS(socklist[host]),
&readable,
0,
0,
&waitlen))) {
if (nready == SOCKET_ERROR) {
if (SOCKET_ERRNO == SOCKET_EINTR)
goto retry;
retval = SOCKET_ERRNO;
goto out;
}
if ((cc = recv(socklist[host],
reply->data, (int) reply->length,
0)) == SOCKET_ERROR)
{
/* man page says error could be:
EBADF: won't happen
ENOTSOCK: it's a socket.
EWOULDBLOCK: not marked non-blocking, and we selected.
EINTR: could happen
EFAULT: we allocated the reply packet.
In addition, net related errors like ECONNREFUSED
are possble (but undocumented). Assume anything
other than EINTR is a permanent error for the
server (i.e. don't set sent = 1).
*/
if (SOCKET_ERRNO == SOCKET_EINTR)
sent = 1;
continue;
}
/* We might consider here verifying that the reply
came from one of the KDC's listed for that address type,
but that check can be fouled by some implementations of
some network types which might show a loopback return
address, for example, if the KDC is on the same host
as the client. */
reply->length = cc;
retval = 0;
goto out;
} else if (nready == 0) {
/* timeout */
sent = 1;
}
/* not ready, go on to next server */
}
if (!sent) {
/* never were able to send to any servers; give up */
retval = KRB5_KDC_UNREACH;
break;
}
}
retval = KRB5_KDC_UNREACH;
out:
for (i = 0; i < addrs.naddrs; i++)
if (socklist[i] != INVALID_SOCKET)
(void) closesocket (socklist[i]);
#if 0
SOCKET_CLEANUP(); /* Done with sockets for now */
#endif
krb5int_free_addrlist (&addrs);
krb5_xfree(socklist);
if (retval) {
free(reply->data);
reply->data = 0;
reply->length = 0;
}
return retval;
}
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