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 } 319