xref: /freebsd/crypto/heimdal/lib/krb5/send_to_kdc.c (revision 6a068746777241722b2b32c5d0bc443a2a64d80b)
1 /*
2  * Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
3  * (Royal Institute of Technology, Stockholm, Sweden).
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * 3. Neither the name of the Institute nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include "krb5_locl.h"
35 #include "send_to_kdc_plugin.h"
36 
37 struct send_to_kdc {
38     krb5_send_to_kdc_func func;
39     void *data;
40 };
41 
42 /*
43  * send the data in `req' on the socket `fd' (which is datagram iff udp)
44  * waiting `tmout' for a reply and returning the reply in `rep'.
45  * iff limit read up to this many bytes
46  * returns 0 and data in `rep' if succesful, otherwise -1
47  */
48 
49 static int
recv_loop(krb5_socket_t fd,time_t tmout,int udp,size_t limit,krb5_data * rep)50 recv_loop (krb5_socket_t fd,
51 	   time_t tmout,
52 	   int udp,
53 	   size_t limit,
54 	   krb5_data *rep)
55 {
56      fd_set fdset;
57      struct timeval timeout;
58      int ret;
59      int nbytes;
60 
61 #ifndef NO_LIMIT_FD_SETSIZE
62      if (fd >= FD_SETSIZE) {
63 	 return -1;
64      }
65 #endif
66 
67      krb5_data_zero(rep);
68      do {
69 	 FD_ZERO(&fdset);
70 	 FD_SET(fd, &fdset);
71 	 timeout.tv_sec  = tmout;
72 	 timeout.tv_usec = 0;
73 	 ret = select (fd + 1, &fdset, NULL, NULL, &timeout);
74 	 if (ret < 0) {
75 	     if (errno == EINTR)
76 		 continue;
77 	     return -1;
78 	 } else if (ret == 0) {
79 	     return 0;
80 	 } else {
81 	     void *tmp;
82 
83 	     if (rk_SOCK_IOCTL (fd, FIONREAD, &nbytes) < 0) {
84 		 krb5_data_free (rep);
85 		 return -1;
86 	     }
87 	     if(nbytes <= 0)
88 		 return 0;
89 
90 	     if (limit)
91 		 nbytes = min((size_t)nbytes, limit - rep->length);
92 
93 	     tmp = realloc (rep->data, rep->length + nbytes);
94 	     if (tmp == NULL) {
95 		 krb5_data_free (rep);
96 		 return -1;
97 	     }
98 	     rep->data = tmp;
99 	     ret = recv (fd, (char*)tmp + rep->length, nbytes, 0);
100 	     if (ret < 0) {
101 		 krb5_data_free (rep);
102 		 return -1;
103 	     }
104 	     rep->length += ret;
105 	 }
106      } while(!udp && (limit == 0 || rep->length < limit));
107      return 0;
108 }
109 
110 /*
111  * Send kerberos requests and receive a reply on a udp or any other kind
112  * of a datagram socket.  See `recv_loop'.
113  */
114 
115 static int
send_and_recv_udp(krb5_socket_t fd,time_t tmout,const krb5_data * req,krb5_data * rep)116 send_and_recv_udp(krb5_socket_t fd,
117 		  time_t tmout,
118 		  const krb5_data *req,
119 		  krb5_data *rep)
120 {
121     if (send (fd, req->data, req->length, 0) < 0)
122 	return -1;
123 
124     return recv_loop(fd, tmout, 1, 0, rep);
125 }
126 
127 /*
128  * `send_and_recv' for a TCP (or any other stream) socket.
129  * Since there are no record limits on a stream socket the protocol here
130  * is to prepend the request with 4 bytes of its length and the reply
131  * is similarly encoded.
132  */
133 
134 static int
send_and_recv_tcp(krb5_socket_t fd,time_t tmout,const krb5_data * req,krb5_data * rep)135 send_and_recv_tcp(krb5_socket_t fd,
136 		  time_t tmout,
137 		  const krb5_data *req,
138 		  krb5_data *rep)
139 {
140     unsigned char len[4];
141     unsigned long rep_len;
142     krb5_data len_data;
143 
144     _krb5_put_int(len, req->length, 4);
145     if(net_write (fd, len, sizeof(len)) < 0)
146 	return -1;
147     if(net_write (fd, req->data, req->length) < 0)
148 	return -1;
149     if (recv_loop (fd, tmout, 0, 4, &len_data) < 0)
150 	return -1;
151     if (len_data.length != 4) {
152 	krb5_data_free (&len_data);
153 	return -1;
154     }
155     _krb5_get_int(len_data.data, &rep_len, 4);
156     krb5_data_free (&len_data);
157     if (recv_loop (fd, tmout, 0, rep_len, rep) < 0)
158 	return -1;
159     if(rep->length != rep_len) {
160 	krb5_data_free (rep);
161 	return -1;
162     }
163     return 0;
164 }
165 
166 int
_krb5_send_and_recv_tcp(krb5_socket_t fd,time_t tmout,const krb5_data * req,krb5_data * rep)167 _krb5_send_and_recv_tcp(krb5_socket_t fd,
168 			time_t tmout,
169 			const krb5_data *req,
170 			krb5_data *rep)
171 {
172     return send_and_recv_tcp(fd, tmout, req, rep);
173 }
174 
175 /*
176  * `send_and_recv' tailored for the HTTP protocol.
177  */
178 
179 static int
send_and_recv_http(krb5_socket_t fd,time_t tmout,const char * prefix,const krb5_data * req,krb5_data * rep)180 send_and_recv_http(krb5_socket_t fd,
181 		   time_t tmout,
182 		   const char *prefix,
183 		   const krb5_data *req,
184 		   krb5_data *rep)
185 {
186     char *request = NULL;
187     char *str;
188     int ret;
189     int len = base64_encode(req->data, req->length, &str);
190 
191     if(len < 0)
192 	return -1;
193     ret = asprintf(&request, "GET %s%s HTTP/1.0\r\n\r\n", prefix, str);
194     free(str);
195     if (ret < 0 || request == NULL)
196 	return -1;
197     ret = net_write (fd, request, strlen(request));
198     free (request);
199     if (ret < 0)
200 	return ret;
201     ret = recv_loop(fd, tmout, 0, 0, rep);
202     if(ret)
203 	return ret;
204     {
205 	unsigned long rep_len;
206 	char *s, *p;
207 
208 	s = realloc(rep->data, rep->length + 1);
209 	if (s == NULL) {
210 	    krb5_data_free (rep);
211 	    return -1;
212 	}
213 	s[rep->length] = 0;
214 	p = strstr(s, "\r\n\r\n");
215 	if(p == NULL) {
216 	    krb5_data_zero(rep);
217 	    free(s);
218 	    return -1;
219 	}
220 	p += 4;
221 	rep->data = s;
222 	rep->length -= p - s;
223 	if(rep->length < 4) { /* remove length */
224 	    krb5_data_zero(rep);
225 	    free(s);
226 	    return -1;
227 	}
228 	rep->length -= 4;
229 	_krb5_get_int(p, &rep_len, 4);
230 	if (rep_len != rep->length) {
231 	    krb5_data_zero(rep);
232 	    free(s);
233 	    return -1;
234 	}
235 	memmove(rep->data, p + 4, rep->length);
236     }
237     return 0;
238 }
239 
240 static int
init_port(const char * s,int fallback)241 init_port(const char *s, int fallback)
242 {
243     if (s) {
244 	int tmp;
245 
246 	sscanf (s, "%d", &tmp);
247 	return htons(tmp);
248     } else
249 	return fallback;
250 }
251 
252 /*
253  * Return 0 if succesful, otherwise 1
254  */
255 
256 static int
send_via_proxy(krb5_context context,const krb5_krbhst_info * hi,const krb5_data * send_data,krb5_data * receive)257 send_via_proxy (krb5_context context,
258 		const krb5_krbhst_info *hi,
259 		const krb5_data *send_data,
260 		krb5_data *receive)
261 {
262     char *proxy2 = strdup(context->http_proxy);
263     char *proxy  = proxy2;
264     char *prefix = NULL;
265     char *colon;
266     struct addrinfo hints;
267     struct addrinfo *ai, *a;
268     int ret;
269     krb5_socket_t s = rk_INVALID_SOCKET;
270     char portstr[NI_MAXSERV];
271 
272     if (proxy == NULL)
273 	return ENOMEM;
274     if (strncmp (proxy, "http://", 7) == 0)
275 	proxy += 7;
276 
277     colon = strchr(proxy, ':');
278     if(colon != NULL)
279 	*colon++ = '\0';
280     memset (&hints, 0, sizeof(hints));
281     hints.ai_family   = PF_UNSPEC;
282     hints.ai_socktype = SOCK_STREAM;
283     snprintf (portstr, sizeof(portstr), "%d",
284 	      ntohs(init_port (colon, htons(80))));
285     ret = getaddrinfo (proxy, portstr, &hints, &ai);
286     free (proxy2);
287     if (ret)
288 	return krb5_eai_to_heim_errno(ret, errno);
289 
290     for (a = ai; a != NULL; a = a->ai_next) {
291 	s = socket (a->ai_family, a->ai_socktype | SOCK_CLOEXEC, a->ai_protocol);
292 	if (s < 0)
293 	    continue;
294 	rk_cloexec(s);
295 	if (connect (s, a->ai_addr, a->ai_addrlen) < 0) {
296 	    rk_closesocket (s);
297 	    continue;
298 	}
299 	break;
300     }
301     if (a == NULL) {
302 	freeaddrinfo (ai);
303 	return 1;
304     }
305     freeaddrinfo (ai);
306 
307     ret = asprintf(&prefix, "http://%s/", hi->hostname);
308     if(ret < 0 || prefix == NULL) {
309 	close(s);
310 	return 1;
311     }
312     ret = send_and_recv_http(s, context->kdc_timeout,
313 			     prefix, send_data, receive);
314     rk_closesocket (s);
315     free(prefix);
316     if(ret == 0 && receive->length != 0)
317 	return 0;
318     return 1;
319 }
320 
321 static krb5_error_code
send_via_plugin(krb5_context context,krb5_krbhst_info * hi,time_t timeout,const krb5_data * send_data,krb5_data * receive)322 send_via_plugin(krb5_context context,
323 		krb5_krbhst_info *hi,
324 		time_t timeout,
325 		const krb5_data *send_data,
326 		krb5_data *receive)
327 {
328     struct krb5_plugin *list = NULL, *e;
329     krb5_error_code ret;
330 
331     ret = _krb5_plugin_find(context, PLUGIN_TYPE_DATA, KRB5_PLUGIN_SEND_TO_KDC, &list);
332     if(ret != 0 || list == NULL)
333 	return KRB5_PLUGIN_NO_HANDLE;
334 
335     for (e = list; e != NULL; e = _krb5_plugin_get_next(e)) {
336 	krb5plugin_send_to_kdc_ftable *service;
337 	void *ctx;
338 
339 	service = _krb5_plugin_get_symbol(e);
340 	if (service->minor_version != 0)
341 	    continue;
342 
343 	(*service->init)(context, &ctx);
344 	ret = (*service->send_to_kdc)(context, ctx, hi,
345 				      timeout, send_data, receive);
346 	(*service->fini)(ctx);
347 	if (ret == 0)
348 	    break;
349 	if (ret != KRB5_PLUGIN_NO_HANDLE) {
350 	    krb5_set_error_message(context, ret,
351 				   N_("Plugin send_to_kdc failed to "
352 				      "lookup with error: %d", ""), ret);
353 	    break;
354 	}
355     }
356     _krb5_plugin_free(list);
357     return KRB5_PLUGIN_NO_HANDLE;
358 }
359 
360 
361 /*
362  * Send the data `send' to one host from `handle` and get back the reply
363  * in `receive'.
364  */
365 
366 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_sendto(krb5_context context,const krb5_data * send_data,krb5_krbhst_handle handle,krb5_data * receive)367 krb5_sendto (krb5_context context,
368 	     const krb5_data *send_data,
369 	     krb5_krbhst_handle handle,
370 	     krb5_data *receive)
371 {
372      krb5_error_code ret;
373      krb5_socket_t fd;
374      size_t i;
375 
376      krb5_data_zero(receive);
377 
378      for (i = 0; i < context->max_retries; ++i) {
379 	 krb5_krbhst_info *hi;
380 
381 	 while (krb5_krbhst_next(context, handle, &hi) == 0) {
382 	     struct addrinfo *ai, *a;
383 
384 	     _krb5_debug(context, 2,
385 			 "trying to communicate with host %s in realm %s",
386 			 hi->hostname, _krb5_krbhst_get_realm(handle));
387 
388 	     if (context->send_to_kdc) {
389 		 struct send_to_kdc *s = context->send_to_kdc;
390 
391 		 ret = (*s->func)(context, s->data, hi,
392 				  context->kdc_timeout, send_data, receive);
393 		 if (ret == 0 && receive->length != 0)
394 		     goto out;
395 		 continue;
396 	     }
397 
398 	     ret = send_via_plugin(context, hi, context->kdc_timeout,
399 				   send_data, receive);
400 	     if (ret == 0 && receive->length != 0)
401 		 goto out;
402 	     else if (ret != KRB5_PLUGIN_NO_HANDLE)
403 		 continue;
404 
405 	     if(hi->proto == KRB5_KRBHST_HTTP && context->http_proxy) {
406 		 if (send_via_proxy (context, hi, send_data, receive) == 0) {
407 		     ret = 0;
408 		     goto out;
409 		 }
410 		 continue;
411 	     }
412 
413 	     ret = krb5_krbhst_get_addrinfo(context, hi, &ai);
414 	     if (ret)
415 		 continue;
416 
417 	     for (a = ai; a != NULL; a = a->ai_next) {
418 		 fd = socket (a->ai_family, a->ai_socktype | SOCK_CLOEXEC, a->ai_protocol);
419 		 if (rk_IS_BAD_SOCKET(fd))
420 		     continue;
421 		 rk_cloexec(fd);
422 		 if (connect (fd, a->ai_addr, a->ai_addrlen) < 0) {
423 		     rk_closesocket (fd);
424 		     continue;
425 		 }
426 		 switch (hi->proto) {
427 		 case KRB5_KRBHST_HTTP :
428 		     ret = send_and_recv_http(fd, context->kdc_timeout,
429 					      "", send_data, receive);
430 		     break;
431 		 case KRB5_KRBHST_TCP :
432 		     ret = send_and_recv_tcp (fd, context->kdc_timeout,
433 					      send_data, receive);
434 		     break;
435 		 case KRB5_KRBHST_UDP :
436 		     ret = send_and_recv_udp (fd, context->kdc_timeout,
437 					      send_data, receive);
438 		     break;
439 		 }
440 		 rk_closesocket (fd);
441 		 if(ret == 0 && receive->length != 0)
442 		     goto out;
443 	     }
444 	 }
445 	 krb5_krbhst_reset(context, handle);
446      }
447      krb5_clear_error_message (context);
448      ret = KRB5_KDC_UNREACH;
449 out:
450      _krb5_debug(context, 2,
451 		 "result of trying to talk to realm %s = %d",
452 		 _krb5_krbhst_get_realm(handle), ret);
453      return ret;
454 }
455 
456 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_sendto_kdc(krb5_context context,const krb5_data * send_data,const krb5_realm * realm,krb5_data * receive)457 krb5_sendto_kdc(krb5_context context,
458 		const krb5_data *send_data,
459 		const krb5_realm *realm,
460 		krb5_data *receive)
461 {
462     return krb5_sendto_kdc_flags(context, send_data, realm, receive, 0);
463 }
464 
465 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_sendto_kdc_flags(krb5_context context,const krb5_data * send_data,const krb5_realm * realm,krb5_data * receive,int flags)466 krb5_sendto_kdc_flags(krb5_context context,
467 		      const krb5_data *send_data,
468 		      const krb5_realm *realm,
469 		      krb5_data *receive,
470 		      int flags)
471 {
472     krb5_error_code ret;
473     krb5_sendto_ctx ctx;
474 
475     ret = krb5_sendto_ctx_alloc(context, &ctx);
476     if (ret)
477 	return ret;
478     krb5_sendto_ctx_add_flags(ctx, flags);
479     krb5_sendto_ctx_set_func(ctx, _krb5_kdc_retry, NULL);
480 
481     ret = krb5_sendto_context(context, ctx, send_data, *realm, receive);
482     krb5_sendto_ctx_free(context, ctx);
483     return ret;
484 }
485 
486 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_set_send_to_kdc_func(krb5_context context,krb5_send_to_kdc_func func,void * data)487 krb5_set_send_to_kdc_func(krb5_context context,
488 			  krb5_send_to_kdc_func func,
489 			  void *data)
490 {
491     free(context->send_to_kdc);
492     if (func == NULL) {
493 	context->send_to_kdc = NULL;
494 	return 0;
495     }
496 
497     context->send_to_kdc = malloc(sizeof(*context->send_to_kdc));
498     if (context->send_to_kdc == NULL) {
499 	krb5_set_error_message(context, ENOMEM,
500 			       N_("malloc: out of memory", ""));
501 	return ENOMEM;
502     }
503 
504     context->send_to_kdc->func = func;
505     context->send_to_kdc->data = data;
506     return 0;
507 }
508 
509 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_copy_send_to_kdc_func(krb5_context context,krb5_context to)510 _krb5_copy_send_to_kdc_func(krb5_context context, krb5_context to)
511 {
512     if (context->send_to_kdc)
513 	return krb5_set_send_to_kdc_func(to,
514 					 context->send_to_kdc->func,
515 					 context->send_to_kdc->data);
516     else
517 	return krb5_set_send_to_kdc_func(to, NULL, NULL);
518 }
519 
520 
521 
522 struct krb5_sendto_ctx_data {
523     int flags;
524     int type;
525     krb5_sendto_ctx_func func;
526     void *data;
527 };
528 
529 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_sendto_ctx_alloc(krb5_context context,krb5_sendto_ctx * ctx)530 krb5_sendto_ctx_alloc(krb5_context context, krb5_sendto_ctx *ctx)
531 {
532     *ctx = calloc(1, sizeof(**ctx));
533     if (*ctx == NULL) {
534 	krb5_set_error_message(context, ENOMEM,
535 			       N_("malloc: out of memory", ""));
536 	return ENOMEM;
537     }
538     return 0;
539 }
540 
541 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_sendto_ctx_add_flags(krb5_sendto_ctx ctx,int flags)542 krb5_sendto_ctx_add_flags(krb5_sendto_ctx ctx, int flags)
543 {
544     ctx->flags |= flags;
545 }
546 
547 KRB5_LIB_FUNCTION int KRB5_LIB_CALL
krb5_sendto_ctx_get_flags(krb5_sendto_ctx ctx)548 krb5_sendto_ctx_get_flags(krb5_sendto_ctx ctx)
549 {
550     return ctx->flags;
551 }
552 
553 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_sendto_ctx_set_type(krb5_sendto_ctx ctx,int type)554 krb5_sendto_ctx_set_type(krb5_sendto_ctx ctx, int type)
555 {
556     ctx->type = type;
557 }
558 
559 
560 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_sendto_ctx_set_func(krb5_sendto_ctx ctx,krb5_sendto_ctx_func func,void * data)561 krb5_sendto_ctx_set_func(krb5_sendto_ctx ctx,
562 			 krb5_sendto_ctx_func func,
563 			 void *data)
564 {
565     ctx->func = func;
566     ctx->data = data;
567 }
568 
569 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_sendto_ctx_free(krb5_context context,krb5_sendto_ctx ctx)570 krb5_sendto_ctx_free(krb5_context context, krb5_sendto_ctx ctx)
571 {
572     memset(ctx, 0, sizeof(*ctx));
573     free(ctx);
574 }
575 
576 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_sendto_context(krb5_context context,krb5_sendto_ctx ctx,const krb5_data * send_data,const krb5_realm realm,krb5_data * receive)577 krb5_sendto_context(krb5_context context,
578 		    krb5_sendto_ctx ctx,
579 		    const krb5_data *send_data,
580 		    const krb5_realm realm,
581 		    krb5_data *receive)
582 {
583     krb5_error_code ret;
584     krb5_krbhst_handle handle = NULL;
585     int type, freectx = 0;
586     int action;
587 
588     krb5_data_zero(receive);
589 
590     if (ctx == NULL) {
591 	freectx = 1;
592 	ret = krb5_sendto_ctx_alloc(context, &ctx);
593 	if (ret)
594 	    return ret;
595     }
596 
597     type = ctx->type;
598     if (type == 0) {
599 	if ((ctx->flags & KRB5_KRBHST_FLAGS_MASTER) || context->use_admin_kdc)
600 	    type = KRB5_KRBHST_ADMIN;
601 	else
602 	    type = KRB5_KRBHST_KDC;
603     }
604 
605     if ((int)send_data->length > context->large_msg_size)
606 	ctx->flags |= KRB5_KRBHST_FLAGS_LARGE_MSG;
607 
608     /* loop until we get back a appropriate response */
609 
610     do {
611 	action = KRB5_SENDTO_DONE;
612 
613 	krb5_data_free(receive);
614 
615 	if (handle == NULL) {
616 	    ret = krb5_krbhst_init_flags(context, realm, type,
617 					 ctx->flags, &handle);
618 	    if (ret) {
619 		if (freectx)
620 		    krb5_sendto_ctx_free(context, ctx);
621 		return ret;
622 	    }
623 	}
624 
625 	ret = krb5_sendto(context, send_data, handle, receive);
626 	if (ret)
627 	    break;
628 	if (ctx->func) {
629 	    ret = (*ctx->func)(context, ctx, ctx->data, receive, &action);
630 	    if (ret)
631 		break;
632 	}
633 	if (action != KRB5_SENDTO_CONTINUE) {
634 	    krb5_krbhst_free(context, handle);
635 	    handle = NULL;
636 	}
637     } while (action != KRB5_SENDTO_DONE);
638     if (handle)
639 	krb5_krbhst_free(context, handle);
640     if (ret == KRB5_KDC_UNREACH)
641 	krb5_set_error_message(context, ret,
642 			       N_("unable to reach any KDC in realm %s", ""),
643 			       realm);
644     if (ret)
645 	krb5_data_free(receive);
646     if (freectx)
647 	krb5_sendto_ctx_free(context, ctx);
648     return ret;
649 }
650 
651 krb5_error_code KRB5_CALLCONV
_krb5_kdc_retry(krb5_context context,krb5_sendto_ctx ctx,void * data,const krb5_data * reply,int * action)652 _krb5_kdc_retry(krb5_context context, krb5_sendto_ctx ctx, void *data,
653 		const krb5_data *reply, int *action)
654 {
655     krb5_error_code ret;
656     KRB_ERROR error;
657 
658     if(krb5_rd_error(context, reply, &error))
659 	return 0;
660 
661     ret = krb5_error_from_rd_error(context, &error, NULL);
662     krb5_free_error_contents(context, &error);
663 
664     switch(ret) {
665     case KRB5KRB_ERR_RESPONSE_TOO_BIG: {
666 	if (krb5_sendto_ctx_get_flags(ctx) & KRB5_KRBHST_FLAGS_LARGE_MSG)
667 	    break;
668 	krb5_sendto_ctx_add_flags(ctx, KRB5_KRBHST_FLAGS_LARGE_MSG);
669 	*action = KRB5_SENDTO_RESTART;
670 	break;
671     }
672     case KRB5KDC_ERR_SVC_UNAVAILABLE:
673 	*action = KRB5_SENDTO_CONTINUE;
674 	break;
675     }
676     return 0;
677 }
678