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                         continue;
 118                 /* [RFC1035 3.3.13] */
 119                 *mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
 120                 break;
 121         }
 122         ldns_pkt_free(resp);
 123
 124         return *mname ? LDNS_STATUS_OK : LDNS_STATUS_ERR;
 125 }
 126
 127 /* Try to get zone and MNAME from SOA queries. */
 128 ldns_status
 129 ldns_update_soa_zone_mname(const char *fqdn, ldns_resolver *r,
 130     ldns_rr_class c, ldns_rdf **zone_rdf, ldns_rdf **mname_rdf)
 131 {
 132         ldns_rr         *soa_rr, *rr;
 133         ldns_rdf        *soa_zone = NULL, *soa_mname = NULL;
 134         ldns_rdf        *ipaddr, *fqdn_rdf, *tmp;
 135         ldns_rdf        **nslist;
 136         ldns_pkt        *query, *resp;
 137         size_t          i;
 138
 139         /*
 140          * XXX Ok, this cannot be the best way to find this...?
 141          * XXX (I run into weird cache-related stuff here)
 142          */
 143
 144         /* Step 1 - first find a nameserver that should know *something* */
 145         fqdn_rdf = ldns_dname_new_frm_str(fqdn);
 146         query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, c, LDNS_RD);
 147         if (!query) {
 148                 return LDNS_STATUS_ERR;
 149         }
 150         fqdn_rdf = NULL;
 151
 152         ldns_pkt_set_random_id(query);
 153         if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
 154                 ldns_pkt_free(query);
 155                 return LDNS_STATUS_ERR;
 156         }
 157         ldns_pkt_free(query);
 158         if (!resp) {
 159                 return LDNS_STATUS_ERR;
 160         }
 161
 162         /* XXX Is it safe to only look in authority section here? */
 163         while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
 164                 if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
 165                         continue;
 166                 /* [RFC1035 3.3.13] */
 167                 soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
 168                 break;
 169         }
 170         ldns_pkt_free(resp);
 171         if (!soa_rr) {
 172                 return LDNS_STATUS_ERR;
 173         }
 174
 175         /* Step 2 - find SOA MNAME IP address, add to resolver */
 176         query = ldns_pkt_query_new(soa_mname, LDNS_RR_TYPE_A, c, LDNS_RD);
 177         if (!query) {
 178                 return LDNS_STATUS_ERR;
 179         }
 180         soa_mname = NULL;
 181
 182         ldns_pkt_set_random_id(query);
 183         if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
 184                 ldns_pkt_free(query);
 185                 return LDNS_STATUS_ERR;
 186         }
 187         ldns_pkt_free(query);
 188         if (!resp) {
 189                 return LDNS_STATUS_ERR;
 190         }
 191
 192         if (ldns_pkt_ancount(resp) == 0) {
 193                 ldns_pkt_free(resp);
 194                 return LDNS_STATUS_ERR;
 195         }
 196
 197         /* XXX There may be more than one answer RR here. */
 198         rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp));
 199         ipaddr = ldns_rr_rdf(rr, 0);
 200
 201         /* Put the SOA mname IP first in the nameserver list. */
 202         nslist = ldns_resolver_nameservers(r);
 203         for (i = 0; i < ldns_resolver_nameserver_count(r); i++) {
 204                 if (ldns_rdf_compare(ipaddr, nslist[i]) == 0) {
 205                         if (i) {
 206                                 tmp = nslist[0];
 207                                 nslist[0] = nslist[i];
 208                                 nslist[i] = tmp;
 209                         }
 210                         break;
 211                 }
 212         }
 213         if (i >= ldns_resolver_nameserver_count(r)) {
 214                 /* SOA mname was not part of the resolver so add it first. */
 215                 (void) ldns_resolver_push_nameserver(r, ipaddr);
 216                 nslist = ldns_resolver_nameservers(r);
 217                 i = ldns_resolver_nameserver_count(r) - 1;
 218                 tmp = nslist[0];
 219                 nslist[0] = nslist[i];
 220                 nslist[i] = tmp;
 221         }
 222         ldns_pkt_free(resp);
 223
 224         /* Make sure to ask the first in the list, i.e SOA mname */
 225         ldns_resolver_set_random(r, false);
 226
 227         /* Step 3 - Redo SOA query, sending to SOA MNAME directly. */
 228         fqdn_rdf = ldns_dname_new_frm_str(fqdn);
 229         query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, c, LDNS_RD);
 230         if (!query) {
 231                 return LDNS_STATUS_ERR;
 232         }
 233         fqdn_rdf = NULL;
 234
 235         ldns_pkt_set_random_id(query);
 236         if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
 237                 ldns_pkt_free(query);
 238                 return LDNS_STATUS_ERR;
 239         }
 240         ldns_pkt_free(query);
 241         if (!resp) {
 242                 return LDNS_STATUS_ERR;
 243         }
 244
 245         /* XXX Is it safe to only look in authority section here, too? */
 246         while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
 247                 if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
 248                         continue;
 249                 /* [RFC1035 3.3.13] */
 250                 soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
 251                 soa_zone = ldns_rdf_clone(ldns_rr_owner(soa_rr));
 252                 break;
 253         }
 254         ldns_pkt_free(resp);
 255         if (!soa_rr) {
 256                 return LDNS_STATUS_ERR;
 257         }
 258
 259         /* That seems to have worked, pass results to caller. */
 260         *zone_rdf = soa_zone;
 261         *mname_rdf = soa_mname;
 262         return LDNS_STATUS_OK;
 263 }
 264
 265 /*
 266  * ldns_update_{get,set}_{zo,pr,up,ad}count
 267  */
 268
 269 uint16_t
 270 ldns_update_zocount(const ldns_pkt *p)
 271 {
 272         return ldns_pkt_qdcount(p);
 273 }
 274
 275 uint16_t
 276 ldns_update_prcount(const ldns_pkt *p)
 277 {
 278         return ldns_pkt_ancount(p);
 279 }
 280
 281 uint16_t
 282 ldns_update_upcount(const ldns_pkt *p)
 283 {
 284         return ldns_pkt_nscount(p);
 285 }
 286
 287 uint16_t
 288 ldns_update_ad(const ldns_pkt *p)
 289 {
 290         return ldns_pkt_arcount(p);
 291 }
 292
 293 void
 294 ldns_update_set_zo(ldns_pkt *p, uint16_t v)
 295 {
 296         ldns_pkt_set_qdcount(p, v);
 297 }
 298
 299 void
 300 ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
 301 {
 302         ldns_pkt_set_ancount(p, v);
 303 }
 304
 305 void
 306 ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
 307 {
 308         ldns_pkt_set_nscount(p, v);
 309 }
 310
 311 void
 312 ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
 313 {
 314         ldns_pkt_set_arcount(p, v);
 315 }