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update.c

/* update.c
 *
 * Functions for RFC 2136 Dynamic Update
 *
 * Copyright (c) 2005-2006, NLnet Labs. All rights reserved.
 *
 * See LICENSE for the license.
 */

#include <ldns/config.h>

#include <ldns/ldns.h>

#include <strings.h>
#include <stdlib.h>
#include <limits.h>

/*
 * RFC 2136 sections mapped to RFC 1035:
 *              zone/ZO -- QD/question
 *     prerequisites/PR -- AN/answers
 *           updates/UP -- NS/authority records
 *   additional data/AD -- AR/additional records
 */

ldns_pkt *
00027 ldns_update_pkt_new(ldns_rdf *zone_rdf, ldns_rr_class class,
    ldns_rr_list *pr_rrlist, ldns_rr_list *up_rrlist, ldns_rr_list *ad_rrlist)
{
      ldns_pkt *p;

      if (!zone_rdf || !up_rrlist) {
            return NULL;
      }

      if (class == 0) { 
            class = LDNS_RR_CLASS_IN;
      }

      /* Create packet, fill in Zone Section. */
      p = ldns_pkt_query_new(zone_rdf, LDNS_RR_TYPE_SOA, class, LDNS_RD);
      if (!p) {
            return NULL;
      }
      zone_rdf = NULL; /* No longer safe to use. */

      ldns_pkt_set_opcode(p, LDNS_PACKET_UPDATE);

      ldns_rr_list_deep_free(p->_authority);

      ldns_pkt_set_authority(p, ldns_rr_list_clone(up_rrlist));

      ldns_update_set_upcount(p, ldns_rr_list_rr_count(up_rrlist));

      if (pr_rrlist) {
            ldns_rr_list_deep_free(p->_answer); /*XXX access function */
            ldns_pkt_set_answer(p, ldns_rr_list_clone(pr_rrlist));
            ldns_update_set_prcount(p, ldns_rr_list_rr_count(pr_rrlist));
      }

      if (ad_rrlist) {
            ldns_rr_list_deep_free(p->_additional);
            ldns_pkt_set_additional(p, ldns_rr_list_clone(ad_rrlist));
            ldns_update_set_adcount(p, ldns_rr_list_rr_count(ad_rrlist));
      }
      return p;
}

ldns_status
00070 ldns_update_pkt_tsig_add(ldns_pkt *p, ldns_resolver *r)
{
#ifdef HAVE_SSL
      uint16_t fudge = 300; /* Recommended fudge. [RFC2845 6.4]  */
      if (ldns_resolver_tsig_keyname(r) && ldns_resolver_tsig_keydata(r))
            return ldns_pkt_tsig_sign(p, ldns_resolver_tsig_keyname(r),
                ldns_resolver_tsig_keydata(r), fudge,
                ldns_resolver_tsig_algorithm(r), NULL);
#else
      (void)p;
      (void)r;
#endif /* HAVE_SSL */
      /* No TSIG to do. */
      return LDNS_STATUS_OK;
}

/* Move to higher.c or similar? */
/* XXX doc */
ldns_status
ldns_update_soa_mname(ldns_rdf *zone, ldns_resolver *r,
    ldns_rr_class class, ldns_rdf **mname)
{
      ldns_rr           *soa_rr;
      ldns_pkt    *query, *resp;

      /* Nondestructive, so clone 'zone' here */
      query = ldns_pkt_query_new(ldns_rdf_clone(zone), LDNS_RR_TYPE_SOA,
          class, LDNS_RD);
      if (!query) {
            return LDNS_STATUS_ERR;
      }

      ldns_pkt_set_random_id(query);
      if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
            ldns_pkt_free(query);
            return LDNS_STATUS_ERR;
      }
      ldns_pkt_free(query);
      if (!resp) {
            return LDNS_STATUS_ERR;
      }

      /* Expect a SOA answer. */
      *mname = NULL;
      while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp)))) {
            if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
                  continue;
            /* [RFC1035 3.3.13] */
            *mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
            break;
      }
      ldns_pkt_free(resp);

      return *mname ? LDNS_STATUS_OK : LDNS_STATUS_ERR;
}

/* Try to get zone and MNAME from SOA queries. */
ldns_status
ldns_update_soa_zone_mname(const char *fqdn, ldns_resolver *r,
    ldns_rr_class class, ldns_rdf **zone_rdf, ldns_rdf **mname_rdf)
{
      ldns_rr           *soa_rr, *rr;
      ldns_rdf    *soa_zone = NULL, *soa_mname = NULL;
      ldns_rdf    *ipaddr, *fqdn_rdf, *tmp;
      ldns_rdf    **nslist;
      ldns_pkt    *query, *resp;
      size_t            i;

      /* 
       * XXX Ok, this cannot be the best way to find this...?
       * XXX (I run into weird cache-related stuff here)
       */

      /* Step 1 - first find a nameserver that should know *something* */
      fqdn_rdf = ldns_dname_new_frm_str(fqdn);
      query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, class, LDNS_RD);
      if (!query) {
            return LDNS_STATUS_ERR;
      }
      fqdn_rdf = NULL;

      ldns_pkt_set_random_id(query);
      if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
            ldns_pkt_free(query);
            return LDNS_STATUS_ERR;
      }
      ldns_pkt_free(query);
      if (!resp) {
            return LDNS_STATUS_ERR;
      }

      /* XXX Is it safe to only look in authority section here? */
      while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
            if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
                  continue;
            /* [RFC1035 3.3.13] */
            soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
            break;
      }
      ldns_pkt_free(resp);
      if (!soa_rr) {
            return LDNS_STATUS_ERR;
      }

      /* Step 2 - find SOA MNAME IP address, add to resolver */
      query = ldns_pkt_query_new(soa_mname, LDNS_RR_TYPE_A, class, LDNS_RD);
      if (!query) {
            return LDNS_STATUS_ERR;
      }
      soa_mname = NULL;

      ldns_pkt_set_random_id(query);
      if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
            ldns_pkt_free(query);
            return LDNS_STATUS_ERR;
      }
      ldns_pkt_free(query);
      if (!resp) {
            return LDNS_STATUS_ERR;
      }

      if (ldns_pkt_ancount(resp) == 0) {
            ldns_pkt_free(resp);
            return LDNS_STATUS_ERR;
      }

      /* XXX There may be more than one answer RR here. */
      rr = ldns_rr_list_pop_rr(ldns_pkt_answer(resp));
      ipaddr = ldns_rr_rdf(rr, 0);

      /* Put the SOA mname IP first in the nameserver list. */
      nslist = ldns_resolver_nameservers(r);
      for (i = 0; i < ldns_resolver_nameserver_count(r); i++) {
            if (ldns_rdf_compare(ipaddr, nslist[i]) == 0) {
                  if (i) {
                        tmp = nslist[0];
                        nslist[0] = nslist[i];
                        nslist[i] = tmp;
                  }
                  break;
            }
      }
      if (i >= ldns_resolver_nameserver_count(r)) {
            /* SOA mname was not part of the resolver so add it first. */
            (void) ldns_resolver_push_nameserver(r, ipaddr);
            nslist = ldns_resolver_nameservers(r);
            i = ldns_resolver_nameserver_count(r) - 1;
            tmp = nslist[0];
            nslist[0] = nslist[i];
            nslist[i] = tmp;
      }
      ldns_pkt_free(resp);

      /* Make sure to ask the first in the list, i.e SOA mname */
      ldns_resolver_set_random(r, false);

      /* Step 3 - Redo SOA query, sending to SOA MNAME directly. */
      fqdn_rdf = ldns_dname_new_frm_str(fqdn);
      query = ldns_pkt_query_new(fqdn_rdf, LDNS_RR_TYPE_SOA, class, LDNS_RD);
      if (!query) {
            return LDNS_STATUS_ERR;
      }
      fqdn_rdf = NULL;

      ldns_pkt_set_random_id(query);
      if (ldns_resolver_send_pkt(&resp, r, query) != LDNS_STATUS_OK) {
            ldns_pkt_free(query);
            return LDNS_STATUS_ERR;
      }
      ldns_pkt_free(query);
      if (!resp) {
            return LDNS_STATUS_ERR;
      }

      /* XXX Is it safe to only look in authority section here, too? */
      while ((soa_rr = ldns_rr_list_pop_rr(ldns_pkt_authority(resp)))) {
            if (ldns_rr_get_type(soa_rr) != LDNS_RR_TYPE_SOA)
                  continue;
            /* [RFC1035 3.3.13] */
            soa_mname = ldns_rdf_clone(ldns_rr_rdf(soa_rr, 0));
            soa_zone = ldns_rdf_clone(ldns_rr_owner(soa_rr));
            break;
      }
      ldns_pkt_free(resp);
      if (!soa_rr) {
            return LDNS_STATUS_ERR;
      }

      /* That seems to have worked, pass results to caller. */
      *zone_rdf = soa_zone;
      *mname_rdf = soa_mname;
      return LDNS_STATUS_OK;
}     

/*
 * ldns_update_{get,set}_{zo,pr,up,ad}count
 */

uint16_t
00269 ldns_update_zocount(const ldns_pkt *p)
{
      return ldns_pkt_qdcount(p);
}

uint16_t
00275 ldns_update_prcount(const ldns_pkt *p)
{
      return ldns_pkt_ancount(p);
}

uint16_t
00281 ldns_update_upcount(const ldns_pkt *p)
{
      return ldns_pkt_nscount(p);
}

uint16_t
ldns_update_ad(const ldns_pkt *p)
{
      return ldns_pkt_arcount(p);
}

void
ldns_update_set_zo(ldns_pkt *p, uint16_t v)
{
      ldns_pkt_set_qdcount(p, v);
}

void
00299 ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
{
      ldns_pkt_set_ancount(p, v);
}

void
00305 ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
{
      ldns_pkt_set_nscount(p, v);
}

void
00311 ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
{
      ldns_pkt_set_arcount(p, v);
}

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