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    const ldns_rr_list *pr_rrlist, const ldns_rr_list *up_rrlist, const 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, const 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	ldns_resolver   *tmp_r;
139	size_t		i;
140
141	/*
142	 * XXX Ok, this cannot be the best way to find this...?
143	 * XXX (I run into weird cache-related stuff here)
144	 */
145
146	/* Step 1 - first find a nameserver that should know *something* */
147	fqdn_rdf = ldns_dname_new_frm_str(fqdn);
148	query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, c, LDNS_RD);
149	if (!query) {
150		return LDNS_STATUS_ERR;
151	}
152	fqdn_rdf = NULL;
153
154	ldns_pkt_set_random_id(query);
155	if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
156		ldns_pkt_free(query);
157		return LDNS_STATUS_ERR;
158	}
159	ldns_pkt_free(query);
160	if (!resp) {
161		return LDNS_STATUS_ERR;
162	}
163
164	/* XXX Is it safe to only look in authority section here? */
165	while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
166		if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA
167				|| ldns_rr_rdf(soa_rr, 0) == NULL)
168			continue;
169		/* [RFC1035 3.3.13] */
170		soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
171		break;
172	}
173	ldns_pkt_free(resp);
174	if (!soa_rr) {
175		return LDNS_STATUS_ERR;
176	}
177
178	/* Step 2 - find SOA MNAME IP address, add to resolver */
179	query = ldns_pkt_query_new(soa_mname, LDNS_RR_TYPE_A, c, LDNS_RD);
180	if (!query) {
181		return LDNS_STATUS_ERR;
182	}
183	soa_mname = NULL;
184
185	ldns_pkt_set_random_id(query);
186	if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
187		ldns_pkt_free(query);
188		return LDNS_STATUS_ERR;
189	}
190	ldns_pkt_free(query);
191	if (!resp) {
192		return LDNS_STATUS_ERR;
193	}
194
195	if (ldns_pkt_ancount(resp) == 0) {
196		ldns_pkt_free(resp);
197		return LDNS_STATUS_ERR;
198	}
199
200	/* XXX There may be more than one answer RR here. */
201	rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp));
202	ipaddr = ldns_rr_rdf(rr, 0);
203
204	/* Put the SOA mname IP first in the nameserver list. */
205	if (!(tmp_r = ldns_resolver_clone(r))) {
206		return LDNS_STATUS_MEM_ERR;
207	}
208	nslist = ldns_resolver_nameservers(tmp_r);
209	for (i = 0; i < ldns_resolver_nameserver_count(tmp_r); i++) {
210		if (ldns_rdf_compare(ipaddr, nslist[i]) == 0) {
211			if (i) {
212				tmp = nslist[0];
213				nslist[0] = nslist[i];
214				nslist[i] = tmp;
215			}
216			break;
217		}
218	}
219	if (i >= ldns_resolver_nameserver_count(tmp_r)) {
220		/* SOA mname was not part of the resolver so add it first. */
221		(void) ldns_resolver_push_nameserver(tmp_r, ipaddr);
222		nslist = ldns_resolver_nameservers(tmp_r);
223		i = ldns_resolver_nameserver_count(tmp_r) - 1;
224		tmp = nslist[0];
225		nslist[0] = nslist[i];
226		nslist[i] = tmp;
227	}
228	ldns_pkt_free(resp);
229
230	/* Make sure to ask the first in the list, i.e SOA mname */
231	ldns_resolver_set_random(tmp_r, false);
232
233	/* Step 3 - Redo SOA query, sending to SOA MNAME directly. */
234	fqdn_rdf = ldns_dname_new_frm_str(fqdn);
235	query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, c, LDNS_RD);
236	if (!query) {
237		ldns_resolver_free(tmp_r);
238		return LDNS_STATUS_ERR;
239	}
240	fqdn_rdf = NULL;
241
242	ldns_pkt_set_random_id(query);
243	if (ldns_resolver_send_pkt(&resp, tmp_r, query) != LDNS_STATUS_OK) {
244		ldns_pkt_free(query);
245		ldns_resolver_free(tmp_r);
246		return LDNS_STATUS_ERR;
247	}
248	ldns_resolver_free(tmp_r);
249	ldns_pkt_free(query);
250	if (!resp) {
251		return LDNS_STATUS_ERR;
252	}
253
254	/* XXX Is it safe to only look in authority section here, too? */
255	while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
256		if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA
257				|| ldns_rr_rdf(soa_rr, 0) == NULL)
258			continue;
259		/* [RFC1035 3.3.13] */
260		soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
261		soa_zone = ldns_rdf_clone(ldns_rr_owner(soa_rr));
262		break;
263	}
264	ldns_pkt_free(resp);
265	if (!soa_rr) {
266		return LDNS_STATUS_ERR;
267	}
268
269	/* That seems to have worked, pass results to caller. */
270	*zone_rdf = soa_zone;
271	*mname_rdf = soa_mname;
272	return LDNS_STATUS_OK;
273}
274
275/*
276 * ldns_update_{get,set}_{zo,pr,up,ad}count
277 */
278
279uint16_t
280ldns_update_zocount(const ldns_pkt *p)
281{
282	return ldns_pkt_qdcount(p);
283}
284
285uint16_t
286ldns_update_prcount(const ldns_pkt *p)
287{
288	return ldns_pkt_ancount(p);
289}
290
291uint16_t
292ldns_update_upcount(const ldns_pkt *p)
293{
294	return ldns_pkt_nscount(p);
295}
296
297uint16_t
298ldns_update_ad(const ldns_pkt *p)
299{
300	return ldns_pkt_arcount(p);
301}
302
303void
304ldns_update_set_zo(ldns_pkt *p, uint16_t v)
305{
306	ldns_pkt_set_qdcount(p, v);
307}
308
309void
310ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
311{
312	ldns_pkt_set_ancount(p, v);
313}
314
315void
316ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
317{
318	ldns_pkt_set_nscount(p, v);
319}
320
321void
322ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
323{
324	ldns_pkt_set_arcount(p, v);
325}
326