update.c

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00001 /* update.c
00002  *
00003  * Functions for RFC 2136 Dynamic Update
00004  *
00005  * Copyright (c) 2005-2006, NLnet Labs. All rights reserved.
00006  *
00007  * See LICENSE for the license.
00008  */
00009 
00010 #include <ldns/config.h>
00011 
00012 #include <ldns/ldns.h>
00013 
00014 #include <strings.h>
00015 #include <stdlib.h>
00016 #include <limits.h>
00017 
00018 /*
00019  * RFC 2136 sections mapped to RFC 1035:
00020  *              zone/ZO -- QD/question
00021  *     prerequisites/PR -- AN/answers
00022  *           updates/UP -- NS/authority records
00023  *   additional data/AD -- AR/additional records
00024  */
00025 
00026 ldns_pkt *
00027 ldns_update_pkt_new(ldns_rdf *zone_rdf, ldns_rr_class class,
00028     ldns_rr_list *pr_rrlist, ldns_rr_list *up_rrlist, ldns_rr_list *ad_rrlist)
00029 {
00030         ldns_pkt *p;
00031 
00032         if (!zone_rdf || !up_rrlist) {
00033                 return NULL;
00034         }
00035 
00036         if (class == 0) { 
00037                 class = LDNS_RR_CLASS_IN;
00038         }
00039 
00040         /* Create packet, fill in Zone Section. */
00041         p = ldns_pkt_query_new(zone_rdf, LDNS_RR_TYPE_SOA, class, LDNS_RD);
00042         if (!p) {
00043                 return NULL;
00044         }
00045         zone_rdf = NULL; /* No longer safe to use. */
00046 
00047         ldns_pkt_set_opcode(p, LDNS_PACKET_UPDATE);
00048 
00049         ldns_rr_list_deep_free(p->_authority);
00050 
00051         ldns_pkt_set_authority(p, ldns_rr_list_clone(up_rrlist));
00052 
00053         ldns_update_set_upcount(p, ldns_rr_list_rr_count(up_rrlist));
00054 
00055         if (pr_rrlist) {
00056                 ldns_rr_list_deep_free(p->_answer); /*XXX access function */
00057                 ldns_pkt_set_answer(p, ldns_rr_list_clone(pr_rrlist));
00058                 ldns_update_set_prcount(p, ldns_rr_list_rr_count(pr_rrlist));
00059         }
00060 
00061         if (ad_rrlist) {
00062                 ldns_rr_list_deep_free(p->_additional);
00063                 ldns_pkt_set_additional(p, ldns_rr_list_clone(ad_rrlist));
00064                 ldns_update_set_adcount(p, ldns_rr_list_rr_count(ad_rrlist));
00065         }
00066         return p;
00067 }
00068 
00069 ldns_status
00070 ldns_update_pkt_tsig_add(ldns_pkt *p, ldns_resolver *r)
00071 {
00072 #ifdef HAVE_SSL
00073         uint16_t fudge = 300; /* Recommended fudge. [RFC2845 6.4]  */
00074         if (ldns_resolver_tsig_keyname(r) && ldns_resolver_tsig_keydata(r))
00075                 return ldns_pkt_tsig_sign(p, ldns_resolver_tsig_keyname(r),
00076                     ldns_resolver_tsig_keydata(r), fudge,
00077                     ldns_resolver_tsig_algorithm(r), NULL);
00078 #else
00079         (void)p;
00080         (void)r;
00081 #endif /* HAVE_SSL */
00082         /* No TSIG to do. */
00083         return LDNS_STATUS_OK;
00084 }
00085 
00086 /* Move to higher.c or similar? */
00087 /* XXX doc */
00088 ldns_status
00089 ldns_update_soa_mname(ldns_rdf *zone, ldns_resolver *r,
00090     ldns_rr_class class, ldns_rdf **mname)
00091 {
00092         ldns_rr         *soa_rr;
00093         ldns_pkt        *query, *resp;
00094 
00095         /* Nondestructive, so clone 'zone' here */
00096         query = ldns_pkt_query_new(ldns_rdf_clone(zone), LDNS_RR_TYPE_SOA,
00097             class, LDNS_RD);
00098         if (!query) {
00099                 return LDNS_STATUS_ERR;
00100         }
00101 
00102         ldns_pkt_set_random_id(query);
00103         if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
00104                 ldns_pkt_free(query);
00105                 return LDNS_STATUS_ERR;
00106         }
00107         ldns_pkt_free(query);
00108         if (!resp) {
00109                 return LDNS_STATUS_ERR;
00110         }
00111 
00112         /* Expect a SOA answer. */
00113         *mname = NULL;
00114         while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp)))) {
00115                 if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
00116                         continue;
00117                 /* [RFC1035 3.3.13] */
00118                 *mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
00119                 break;
00120         }
00121         ldns_pkt_free(resp);
00122 
00123         return *mname ? LDNS_STATUS_OK : LDNS_STATUS_ERR;
00124 }
00125 
00126 /* Try to get zone and MNAME from SOA queries. */
00127 ldns_status
00128 ldns_update_soa_zone_mname(const char *fqdn, ldns_resolver *r,
00129     ldns_rr_class class, ldns_rdf **zone_rdf, ldns_rdf **mname_rdf)
00130 {
00131         ldns_rr         *soa_rr, *rr;
00132         ldns_rdf        *soa_zone = NULL, *soa_mname = NULL;
00133         ldns_rdf        *ipaddr, *fqdn_rdf, *tmp;
00134         ldns_rdf        **nslist;
00135         ldns_pkt        *query, *resp;
00136         size_t          i;
00137 
00138         /* 
00139          * XXX Ok, this cannot be the best way to find this...?
00140          * XXX (I run into weird cache-related stuff here)
00141          */
00142 
00143         /* Step 1 - first find a nameserver that should know *something* */
00144         fqdn_rdf = ldns_dname_new_frm_str(fqdn);
00145         query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, class, LDNS_RD);
00146         if (!query) {
00147                 return LDNS_STATUS_ERR;
00148         }
00149         fqdn_rdf = NULL;
00150 
00151         ldns_pkt_set_random_id(query);
00152         if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
00153                 ldns_pkt_free(query);
00154                 return LDNS_STATUS_ERR;
00155         }
00156         ldns_pkt_free(query);
00157         if (!resp) {
00158                 return LDNS_STATUS_ERR;
00159         }
00160 
00161         /* XXX Is it safe to only look in authority section here? */
00162         while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
00163                 if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
00164                         continue;
00165                 /* [RFC1035 3.3.13] */
00166                 soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
00167                 break;
00168         }
00169         ldns_pkt_free(resp);
00170         if (!soa_rr) {
00171                 return LDNS_STATUS_ERR;
00172         }
00173 
00174         /* Step 2 - find SOA MNAME IP address, add to resolver */
00175         query = ldns_pkt_query_new(soa_mname, LDNS_RR_TYPE_A, class, LDNS_RD);
00176         if (!query) {
00177                 return LDNS_STATUS_ERR;
00178         }
00179         soa_mname = NULL;
00180 
00181         ldns_pkt_set_random_id(query);
00182         if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
00183                 ldns_pkt_free(query);
00184                 return LDNS_STATUS_ERR;
00185         }
00186         ldns_pkt_free(query);
00187         if (!resp) {
00188                 return LDNS_STATUS_ERR;
00189         }
00190 
00191         if (ldns_pkt_ancount(resp) == 0) {
00192                 ldns_pkt_free(resp);
00193                 return LDNS_STATUS_ERR;
00194         }
00195 
00196         /* XXX There may be more than one answer RR here. */
00197         rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp));
00198         ipaddr = ldns_rr_rdf(rr, 0);
00199 
00200         /* Put the SOA mname IP first in the nameserver list. */
00201         nslist = ldns_resolver_nameservers(r);
00202         for (i = 0; i < ldns_resolver_nameserver_count(r); i++) {
00203                 if (ldns_rdf_compare(ipaddr, nslist[i]) == 0) {
00204                         if (i) {
00205                                 tmp = nslist[0];
00206                                 nslist[0] = nslist[i];
00207                                 nslist[i] = tmp;
00208                         }
00209                         break;
00210                 }
00211         }
00212         if (i >= ldns_resolver_nameserver_count(r)) {
00213                 /* SOA mname was not part of the resolver so add it first. */
00214                 (void) ldns_resolver_push_nameserver(r, ipaddr);
00215                 nslist = ldns_resolver_nameservers(r);
00216                 i = ldns_resolver_nameserver_count(r) - 1;
00217                 tmp = nslist[0];
00218                 nslist[0] = nslist[i];
00219                 nslist[i] = tmp;
00220         }
00221         ldns_pkt_free(resp);
00222 
00223         /* Make sure to ask the first in the list, i.e SOA mname */
00224         ldns_resolver_set_random(r, false);
00225 
00226         /* Step 3 - Redo SOA query, sending to SOA MNAME directly. */
00227         fqdn_rdf = ldns_dname_new_frm_str(fqdn);
00228         query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, class, LDNS_RD);
00229         if (!query) {
00230                 return LDNS_STATUS_ERR;
00231         }
00232         fqdn_rdf = NULL;
00233 
00234         ldns_pkt_set_random_id(query);
00235         if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
00236                 ldns_pkt_free(query);
00237                 return LDNS_STATUS_ERR;
00238         }
00239         ldns_pkt_free(query);
00240         if (!resp) {
00241                 return LDNS_STATUS_ERR;
00242         }
00243 
00244         /* XXX Is it safe to only look in authority section here, too? */
00245         while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
00246                 if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
00247                         continue;
00248                 /* [RFC1035 3.3.13] */
00249                 soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
00250                 soa_zone = ldns_rdf_clone(ldns_rr_owner(soa_rr));
00251                 break;
00252         }
00253         ldns_pkt_free(resp);
00254         if (!soa_rr) {
00255                 return LDNS_STATUS_ERR;
00256         }
00257 
00258         /* That seems to have worked, pass results to caller. */
00259         *zone_rdf = soa_zone;
00260         *mname_rdf = soa_mname;
00261         return LDNS_STATUS_OK;
00262 }       
00263 
00264 /*
00265  * ldns_update_{get,set}_{zo,pr,up,ad}count
00266  */
00267 
00268 uint16_t
00269 ldns_update_zocount(const ldns_pkt *p)
00270 {
00271         return ldns_pkt_qdcount(p);
00272 }
00273 
00274 uint16_t
00275 ldns_update_prcount(const ldns_pkt *p)
00276 {
00277         return ldns_pkt_ancount(p);
00278 }
00279 
00280 uint16_t
00281 ldns_update_upcount(const ldns_pkt *p)
00282 {
00283         return ldns_pkt_nscount(p);
00284 }
00285 
00286 uint16_t
00287 ldns_update_ad(const ldns_pkt *p)
00288 {
00289         return ldns_pkt_arcount(p);
00290 }
00291 
00292 void
00293 ldns_update_set_zo(ldns_pkt *p, uint16_t v)
00294 {
00295         ldns_pkt_set_qdcount(p, v);
00296 }
00297 
00298 void
00299 ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
00300 {
00301         ldns_pkt_set_ancount(p, v);
00302 }
00303 
00304 void
00305 ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
00306 {
00307         ldns_pkt_set_nscount(p, v);
00308 }
00309 
00310 void
00311 ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
00312 {
00313         ldns_pkt_set_arcount(p, v);
00314 }

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