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     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
  69 ldns_status
  70 ldns_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 */
  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         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
 272 uint16_t
 273 ldns_update_zocount(const ldns_pkt *p)
 274 {
 275         return ldns_pkt_qdcount(p);
 276 }
 277
 278 uint16_t
 279 ldns_update_prcount(const ldns_pkt *p)
 280 {
 281         return ldns_pkt_ancount(p);
 282 }
 283
 284 uint16_t
 285 ldns_update_upcount(const ldns_pkt *p)
 286 {
 287         return ldns_pkt_nscount(p);
 288 }
 289
 290 uint16_t
 291 ldns_update_ad(const ldns_pkt *p)
 292 {
 293         return ldns_pkt_arcount(p);
 294 }
 295
 296 void
 297 ldns_update_set_zo(ldns_pkt *p, uint16_t v)
 298 {
 299         ldns_pkt_set_qdcount(p, v);
 300 }
 301
 302 void
 303 ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
 304 {
 305         ldns_pkt_set_ancount(p, v);
 306 }
 307
 308 void
 309 ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
 310 {
 311         ldns_pkt_set_nscount(p, v);
 312 }
 313
 314 void
 315 ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
 316 {
 317         ldns_pkt_set_arcount(p, v);
 318 }