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
26ldns_pkt *
27ldns_update_pkt_new(ldns_rdf *zone_rdf, ldns_rr_class c,
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
47	ldns_pkt_set_opcode(p, LDNS_PACKET_UPDATE);
48
49	ldns_rr_list_deep_free(p->_authority);
50
51	ldns_pkt_set_authority(p, ldns_rr_list_clone(up_rrlist));
52
53	ldns_update_set_upcount(p, ldns_rr_list_rr_count(up_rrlist));
54
55	if (pr_rrlist) {
56		ldns_rr_list_deep_free(p->_answer); /*XXX access function */
57		ldns_pkt_set_answer(p, ldns_rr_list_clone(pr_rrlist));
58		ldns_update_set_prcount(p, ldns_rr_list_rr_count(pr_rrlist));
59	}
60
61	if (ad_rrlist) {
62		ldns_rr_list_deep_free(p->_additional);
63		ldns_pkt_set_additional(p, ldns_rr_list_clone(ad_rrlist));
64		ldns_update_set_adcount(p, ldns_rr_list_rr_count(ad_rrlist));
65	}
66	return p;
67}
68
69ldns_status
70ldns_update_pkt_tsig_add(ldns_pkt *p, ldns_resolver *r)
71{
72#ifdef HAVE_SSL
73	uint16_t fudge = 300; /* Recommended fudge. [RFC2845 6.4]  */
74	if (ldns_resolver_tsig_keyname(r) && ldns_resolver_tsig_keydata(r))
75		return ldns_pkt_tsig_sign(p, ldns_resolver_tsig_keyname(r),
76		    ldns_resolver_tsig_keydata(r), fudge,
77		    ldns_resolver_tsig_algorithm(r), NULL);
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 */
89ldns_status
90ldns_update_soa_mname(ldns_rdf *zone, ldns_resolver *r,
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 */
97	query = ldns_pkt_query_new(ldns_rdf_clone(zone), LDNS_RR_TYPE_SOA,
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. */
129ldns_status
130ldns_update_soa_zone_mname(const char *fqdn, ldns_resolver *r,
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. */
200	rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp));
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);
219		i = ldns_resolver_nameserver_count(r) - 1;
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
272uint16_t
273ldns_update_zocount(const ldns_pkt *p)
274{
275	return ldns_pkt_qdcount(p);
276}
277
278uint16_t
279ldns_update_prcount(const ldns_pkt *p)
280{
281	return ldns_pkt_ancount(p);
282}
283
284uint16_t
285ldns_update_upcount(const ldns_pkt *p)
286{
287	return ldns_pkt_nscount(p);
288}
289
290uint16_t
291ldns_update_ad(const ldns_pkt *p)
292{
293	return ldns_pkt_arcount(p);
294}
295
296void
297ldns_update_set_zo(ldns_pkt *p, uint16_t v)
298{
299	ldns_pkt_set_qdcount(p, v);
300}
301
302void
303ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
304{
305	ldns_pkt_set_ancount(p, v);
306}
307
308void
309ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
310{
311	ldns_pkt_set_nscount(p, v);
312}
313
314void
315ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
316{
317	ldns_pkt_set_arcount(p, v);
318}
319