update.c
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1 /* update.c
2  *
3  * Functions for RFC 2136 Dynamic Update
4  *
5  * Copyright (c) 2005-2008, NLnet Labs. All rights reserved.
6  *
7  * See LICENSE for the license.
8  */
9 
10 #include <ldns/config.h>
11 
12 #include <ldns/ldns.h>
13 
14 #include <strings.h>
15 #include <stdlib.h>
16 #include <limits.h>
17 
18 /*
19  * RFC 2136 sections mapped to RFC 1035:
20  * zone/ZO -- QD/question
21  * prerequisites/PR -- AN/answers
22  * updates/UP -- NS/authority records
23  * additional data/AD -- AR/additional records
24  */
25 
26 ldns_pkt *
28  ldns_rr_list *pr_rrlist, ldns_rr_list *up_rrlist, ldns_rr_list *ad_rrlist)
29 {
30  ldns_pkt *p;
31 
32  if (!zone_rdf || !up_rrlist) {
33  return NULL;
34  }
35 
36  if (c == 0) {
37  c = LDNS_RR_CLASS_IN;
38  }
39 
40  /* Create packet, fill in Zone Section. */
41  p = ldns_pkt_query_new(zone_rdf, LDNS_RR_TYPE_SOA, c, LDNS_RD);
42  if (!p) {
43  return NULL;
44  }
45  zone_rdf = NULL; /* No longer safe to use. */
46 
48 
50 
52 
54 
55  if (pr_rrlist) {
56  ldns_rr_list_deep_free(p->_answer); /*XXX access function */
59  }
60 
61  if (ad_rrlist) {
65  }
66  return p;
67 }
68 
71 {
72 #ifdef HAVE_SSL
73  uint16_t fudge = 300; /* Recommended fudge. [RFC2845 6.4] */
78 #else
79  /* do nothing */
80  (void)p;
81  (void)r;
82 #endif /* HAVE_SSL */
83  /* No TSIG to do. */
84  return LDNS_STATUS_OK;
85 }
86 
87 /* Move to higher.c or similar? */
88 /* XXX doc */
91  ldns_rr_class c, ldns_rdf **mname)
92 {
93  ldns_rr *soa_rr;
94  ldns_pkt *query, *resp;
95 
96  /* Nondestructive, so clone 'zone' here */
98  c, LDNS_RD);
99  if (!query) {
100  return LDNS_STATUS_ERR;
101  }
102 
103  ldns_pkt_set_random_id(query);
104  if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
105  ldns_pkt_free(query);
106  return LDNS_STATUS_ERR;
107  }
108  ldns_pkt_free(query);
109  if (!resp) {
110  return LDNS_STATUS_ERR;
111  }
112 
113  /* Expect a SOA answer. */
114  *mname = NULL;
115  while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp)))) {
116  if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA
117  || ldns_rr_rdf(soa_rr, 0) == NULL)
118  continue;
119  /* [RFC1035 3.3.13] */
120  *mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
121  break;
122  }
123  ldns_pkt_free(resp);
124 
125  return *mname ? LDNS_STATUS_OK : LDNS_STATUS_ERR;
126 }
127 
128 /* Try to get zone and MNAME from SOA queries. */
131  ldns_rr_class c, ldns_rdf **zone_rdf, ldns_rdf **mname_rdf)
132 {
133  ldns_rr *soa_rr, *rr;
134  ldns_rdf *soa_zone = NULL, *soa_mname = NULL;
135  ldns_rdf *ipaddr, *fqdn_rdf, *tmp;
136  ldns_rdf **nslist;
137  ldns_pkt *query, *resp;
138  size_t i;
139 
140  /*
141  * XXX Ok, this cannot be the best way to find this...?
142  * XXX (I run into weird cache-related stuff here)
143  */
144 
145  /* Step 1 - first find a nameserver that should know *something* */
146  fqdn_rdf = ldns_dname_new_frm_str(fqdn);
147  query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, c, LDNS_RD);
148  if (!query) {
149  return LDNS_STATUS_ERR;
150  }
151  fqdn_rdf = NULL;
152 
153  ldns_pkt_set_random_id(query);
154  if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
155  ldns_pkt_free(query);
156  return LDNS_STATUS_ERR;
157  }
158  ldns_pkt_free(query);
159  if (!resp) {
160  return LDNS_STATUS_ERR;
161  }
162 
163  /* XXX Is it safe to only look in authority section here? */
164  while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
165  if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA
166  || ldns_rr_rdf(soa_rr, 0) == NULL)
167  continue;
168  /* [RFC1035 3.3.13] */
169  soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
170  break;
171  }
172  ldns_pkt_free(resp);
173  if (!soa_rr) {
174  return LDNS_STATUS_ERR;
175  }
176 
177  /* Step 2 - find SOA MNAME IP address, add to resolver */
178  query = ldns_pkt_query_new(soa_mname, LDNS_RR_TYPE_A, c, LDNS_RD);
179  if (!query) {
180  return LDNS_STATUS_ERR;
181  }
182  soa_mname = NULL;
183 
184  ldns_pkt_set_random_id(query);
185  if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
186  ldns_pkt_free(query);
187  return LDNS_STATUS_ERR;
188  }
189  ldns_pkt_free(query);
190  if (!resp) {
191  return LDNS_STATUS_ERR;
192  }
193 
194  if (ldns_pkt_ancount(resp) == 0) {
195  ldns_pkt_free(resp);
196  return LDNS_STATUS_ERR;
197  }
198 
199  /* XXX There may be more than one answer RR here. */
201  ipaddr = ldns_rr_rdf(rr, 0);
202 
203  /* Put the SOA mname IP first in the nameserver list. */
204  nslist = ldns_resolver_nameservers(r);
205  for (i = 0; i < ldns_resolver_nameserver_count(r); i++) {
206  if (ldns_rdf_compare(ipaddr, nslist[i]) == 0) {
207  if (i) {
208  tmp = nslist[0];
209  nslist[0] = nslist[i];
210  nslist[i] = tmp;
211  }
212  break;
213  }
214  }
215  if (i >= ldns_resolver_nameserver_count(r)) {
216  /* SOA mname was not part of the resolver so add it first. */
217  (void) ldns_resolver_push_nameserver(r, ipaddr);
218  nslist = ldns_resolver_nameservers(r);
220  tmp = nslist[0];
221  nslist[0] = nslist[i];
222  nslist[i] = tmp;
223  }
224  ldns_pkt_free(resp);
225 
226  /* Make sure to ask the first in the list, i.e SOA mname */
227  ldns_resolver_set_random(r, false);
228 
229  /* Step 3 - Redo SOA query, sending to SOA MNAME directly. */
230  fqdn_rdf = ldns_dname_new_frm_str(fqdn);
231  query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, c, LDNS_RD);
232  if (!query) {
233  return LDNS_STATUS_ERR;
234  }
235  fqdn_rdf = NULL;
236 
237  ldns_pkt_set_random_id(query);
238  if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
239  ldns_pkt_free(query);
240  return LDNS_STATUS_ERR;
241  }
242  ldns_pkt_free(query);
243  if (!resp) {
244  return LDNS_STATUS_ERR;
245  }
246 
247  /* XXX Is it safe to only look in authority section here, too? */
248  while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
249  if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA
250  || ldns_rr_rdf(soa_rr, 0) == NULL)
251  continue;
252  /* [RFC1035 3.3.13] */
253  soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
254  soa_zone = ldns_rdf_clone(ldns_rr_owner(soa_rr));
255  break;
256  }
257  ldns_pkt_free(resp);
258  if (!soa_rr) {
259  return LDNS_STATUS_ERR;
260  }
261 
262  /* That seems to have worked, pass results to caller. */
263  *zone_rdf = soa_zone;
264  *mname_rdf = soa_mname;
265  return LDNS_STATUS_OK;
266 }
267 
268 /*
269  * ldns_update_{get,set}_{zo,pr,up,ad}count
270  */
271 
272 uint16_t
274 {
275  return ldns_pkt_qdcount(p);
276 }
277 
278 uint16_t
280 {
281  return ldns_pkt_ancount(p);
282 }
283 
284 uint16_t
286 {
287  return ldns_pkt_nscount(p);
288 }
289 
290 uint16_t
292 {
293  return ldns_pkt_arcount(p);
294 }
295 
296 void
298 {
299  ldns_pkt_set_qdcount(p, v);
300 }
301 
302 void
304 {
305  ldns_pkt_set_ancount(p, v);
306 }
307 
308 void
310 {
311  ldns_pkt_set_nscount(p, v);
312 }
313 
314 void
316 {
317  ldns_pkt_set_arcount(p, v);
318 }