update.c

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/* update.c
 *
 * Functions for RFC 2136 Dynamic Update
 *
 * Copyright (c) 2005-2008, 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 *
ldns_update_pkt_new(ldns_rdf *zone_rdf, ldns_rr_class c,
    const ldns_rr_list *pr_rrlist, const ldns_rr_list *up_rrlist, const ldns_rr_list *ad_rrlist)
{
        ldns_pkt *p;
 
        if (!zone_rdf || !up_rrlist) {
                return NULL;
        }
 
        if (c == 0) { 
                c = LDNS_RR_CLASS_IN;
        }
 
        /* Create packet, fill in Zone Section. */
        p = ldns_pkt_query_new(zone_rdf, LDNS_RR_TYPE_SOA, c, 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
ldns_update_pkt_tsig_add(ldns_pkt *p, const 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
        /* do nothing */
        (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 c, 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,
            c, 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
                                || ldns_rr_rdf(soa_rr, 0) == NULL)
                        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 c, 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;
        ldns_resolver   *tmp_r;
        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, c, 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
                                || ldns_rr_rdf(soa_rr, 0) == NULL)
                        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, c, 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. */
        if (!(tmp_r = ldns_resolver_clone(r))) {
                return LDNS_STATUS_MEM_ERR;
        }
        nslist = ldns_resolver_nameservers(tmp_r);
        for (i = 0; i < ldns_resolver_nameserver_count(tmp_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(tmp_r)) {
                /* SOA mname was not part of the resolver so add it first. */
                (void) ldns_resolver_push_nameserver(tmp_r, ipaddr);
                nslist = ldns_resolver_nameservers(tmp_r);
                i = ldns_resolver_nameserver_count(tmp_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(tmp_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, c, LDNS_RD);
        if (!query) {
                ldns_resolver_free(tmp_r);
                return LDNS_STATUS_ERR;
        }
        fqdn_rdf = NULL;
 
        ldns_pkt_set_random_id(query);
        if (ldns_resolver_send_pkt(&resp, tmp_r, query) != LDNS_STATUS_OK) {
                ldns_pkt_free(query);
                ldns_resolver_free(tmp_r);
                return LDNS_STATUS_ERR;
        }
        ldns_resolver_free(tmp_r);
        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
                                || ldns_rr_rdf(soa_rr, 0) == NULL)
                        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
ldns_update_zocount(const ldns_pkt *p)
{
        return ldns_pkt_qdcount(p);
}
 
uint16_t
ldns_update_prcount(const ldns_pkt *p)
{
        return ldns_pkt_ancount(p);
}
 
uint16_t
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
ldns_update_set_prcount(ldns_pkt *p, uint16_t v)
{
        ldns_pkt_set_ancount(p, v);
}
 
void
ldns_update_set_upcount(ldns_pkt *p, uint16_t v)
{
        ldns_pkt_set_nscount(p, v);
}
 
void
ldns_update_set_adcount(ldns_pkt *p, uint16_t v)
{
        ldns_pkt_set_arcount(p, v);
}