contrib/ldns/update.c

   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 *
  27 ldns_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
  69 ldns_status
  70 ldns_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 */
  89 ldns_status
  90 ldns_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. */
 129 ldns_status
 130 ldns_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
 279 uint16_t
 280 ldns_update_zocount(const ldns_pkt *p)
 281 {
 282         return ldns_pkt_qdcount(p);
 283 }
 284
 285 uint16_t
 286 ldns_update_prcount(const ldns_pkt *p)
 287 {
 288         return ldns_pkt_ancount(p);
 289 }
 290
 291 uint16_t
 292 ldns_update_upcount(const ldns_pkt *p)
 293 {
 294         return ldns_pkt_nscount(p);
 295 }
 296
 297 uint16_t
 298 ldns_update_ad(const ldns_pkt *p)
 299 {
 300         return ldns_pkt_arcount(p);
 301 }
 302
 303 void
 304 ldns_update_set_zo(ldns_pkt *p, uint16_t v)
 305 {
 306         ldns_pkt_set_qdcount(p, v);
 307 }
 308
 309 void
 310 ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
 311 {
 312         ldns_pkt_set_ancount(p, v);
 313 }
 314
 315 void
 316 ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
 317 {
 318         ldns_pkt_set_nscount(p, v);
 319 }
 320
 321 void
 322 ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
 323 {
 324         ldns_pkt_set_arcount(p, v);
 325 }