dnsrecord.c   [plain text]

/*
  Linux DNS client library implementation
  Copyright (C) 2006 Krishna Ganugapati <krishnag@centeris.com>
  Copyright (C) 2006 Gerald Carter <jerry@samba.org>
  Copyright (C) 2008 Apple, Inc. All rights reserved.

     ** NOTE! The following LGPL license applies to the libaddns
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  
  02110-1301  USA
*/

#include "dns.h"
#include <assert.h>

DNS_ERROR dns_create_query( TALLOC_CTX *mem_ctx, const char *name,
			    uint16 q_type, uint16 q_class,
			    struct dns_request **preq )
{
	struct dns_request *req;
	struct dns_question *q;
	DNS_ERROR err;

	if (!(req = TALLOC_ZERO_P(mem_ctx, struct dns_request)) ||
	    !(req->questions = TALLOC_ARRAY(req, struct dns_question *, 1)) ||
	    !(req->questions[0] = talloc(req->questions,
					 struct dns_question))) {
		TALLOC_FREE(req);
		return ERROR_DNS_NO_MEMORY;
	}

	req->id = random();

	req->num_questions = 1;
	q = req->questions[0];

	err = dns_domain_name_from_string(q, name, &q->name);
	if (!ERR_DNS_IS_OK(err)) {
		TALLOC_FREE(req);
		return err;
	}

	q->q_type = q_type;
	q->q_class = q_class;

	*preq = req;
	return ERROR_DNS_SUCCESS;
}

DNS_ERROR dns_create_update( TALLOC_CTX *mem_ctx, const char *name,
			     struct dns_update_request **preq )
{
	struct dns_update_request *req;
	struct dns_zone *z;
	DNS_ERROR err;

	if (!(req = TALLOC_ZERO_P(mem_ctx, struct dns_update_request)) ||
	    !(req->zones = TALLOC_ARRAY(req, struct dns_zone *, 1)) ||
	    !(req->zones[0] = talloc(req->zones, struct dns_zone))) {
		TALLOC_FREE(req);
		return ERROR_DNS_NO_MEMORY;
	}

	req->id = random();
	req->flags = 0x2800;	/* Dynamic update */

	req->num_zones = 1;
	z = req->zones[0];

	err = dns_domain_name_from_string(z, name, &z->name);
	if (!ERR_DNS_IS_OK(err)) {
		TALLOC_FREE(req);
		return err;
	}

	z->z_type = QTYPE_SOA;
	z->z_class = DNS_CLASS_IN;

	*preq = req;
	return ERROR_DNS_SUCCESS;
}

DNS_ERROR dns_create_rrec(TALLOC_CTX *mem_ctx, const char *name,
			  uint16 type, uint16 r_class, uint32 ttl,
			  uint16 data_length, uint8 *data,
			  struct dns_rrec **prec)
{
	struct dns_rrec *rec;
	DNS_ERROR err;

	if (!(rec = talloc(mem_ctx, struct dns_rrec))) {
		return ERROR_DNS_NO_MEMORY;
	}

	err = dns_domain_name_from_string(rec, name, &rec->name);
	if (!(ERR_DNS_IS_OK(err))) {
		TALLOC_FREE(rec);
		return err;
	}

	rec->type = type;
	rec->r_class = r_class;
	rec->ttl = ttl;
	rec->data_length = data_length;
	rec->data = talloc_move(rec, &data);

	*prec = rec;
	return ERROR_DNS_SUCCESS;
}

DNS_ERROR dns_create_ptr_record(TALLOC_CTX *mem_ctx,
			    const char * host,
			    uint32 ttl, struct in_addr ip,
			    struct dns_rrec **prec)
{
	DNS_ERROR err;
	char * ptr;

	struct dns_domain_name * name;
	struct dns_buffer * buf;

	buf = dns_create_buffer(mem_ctx);

	ptr = talloc_asprintf(mem_ctx, "%d.%d.%d.%d.in-addr.arpa.",
		(ntohl(ip.s_addr) & 0x000000ff),
		(ntohl(ip.s_addr) & 0x0000ff00) >> 8,
		(ntohl(ip.s_addr) & 0x00ff0000) >> 16,
		(ntohl(ip.s_addr) & 0xff000000) >> 24);

	dns_domain_name_from_string(mem_ctx, host, &name);
	dns_marshall_domain_name(buf, name);

	/* For a PTR record, x.x.x.x.in-addr.arpa is the record name, and the
	 * canonical hostname is the record data.
	 */
	err = dns_create_rrec(mem_ctx, ptr, QTYPE_PTR, DNS_CLASS_IN, ttl,
				buf->offset, (uint8_t *)buf->data, prec);

	return err;
}

DNS_ERROR dns_create_a_record(TALLOC_CTX *mem_ctx, const char *host,
			      uint32 ttl, struct in_addr ip,
			      struct dns_rrec **prec)
{
	uint8 *data;
	DNS_ERROR err;

	if (!(data = (uint8 *)TALLOC_MEMDUP(mem_ctx, (const void *)&ip.s_addr,
					    sizeof(ip.s_addr)))) {
		return ERROR_DNS_NO_MEMORY;
	}

	err = dns_create_rrec(mem_ctx, host, QTYPE_A, DNS_CLASS_IN, ttl,
			      sizeof(ip.s_addr), data, prec);

	if (!ERR_DNS_IS_OK(err)) {
		TALLOC_FREE(data);
	}

	return err;
}

DNS_ERROR dns_create_name_in_use_record(TALLOC_CTX *mem_ctx,
					const char *name,
					const struct in_addr *ip,
					struct dns_rrec **prec)
{
	if (ip != NULL) {
		return dns_create_a_record(mem_ctx, name, 0, *ip, prec);
	}

	return dns_create_rrec(mem_ctx, name, QTYPE_ANY, DNS_CLASS_IN, 0, 0,
			       NULL, prec);
}

DNS_ERROR dns_create_name_not_in_use_record(TALLOC_CTX *mem_ctx,
					    const char *name, uint32 type,
					    struct dns_rrec **prec)
{
	return dns_create_rrec(mem_ctx, name, type, DNS_CLASS_NONE, 0,
			       0, NULL, prec);
}

DNS_ERROR dns_create_delete_record(TALLOC_CTX *mem_ctx, const char *name,
				   uint16 type, uint16 r_class,
				   struct dns_rrec **prec)
{
	return dns_create_rrec(mem_ctx, name, type, r_class, 0, 0, NULL, prec);
}

DNS_ERROR dns_create_tkey_record(TALLOC_CTX *mem_ctx, const char *keyname,
				 const char *algorithm_name, time_t inception,
				 time_t expiration, uint16 mode, uint16 error,
				 uint16 key_length, const uint8 *key,
				 struct dns_rrec **prec)
{
	struct dns_buffer *buf;
	struct dns_domain_name *algorithm;
	DNS_ERROR err;

	if (!(buf = dns_create_buffer(mem_ctx))) {
		return ERROR_DNS_NO_MEMORY;
	}

	err = dns_domain_name_from_string(buf, algorithm_name, &algorithm);
	if (!ERR_DNS_IS_OK(err)) goto error;

	dns_marshall_domain_name(buf, algorithm);
	dns_marshall_uint32(buf, inception);
	dns_marshall_uint32(buf, expiration);
	dns_marshall_uint16(buf, mode);
	dns_marshall_uint16(buf, error);
	dns_marshall_uint16(buf, key_length);
	dns_marshall_buffer(buf, key, key_length);
	dns_marshall_uint16(buf, 0); /* Other Size */

	if (!ERR_DNS_IS_OK(buf->error)) {
		err = buf->error;
		goto error;
	}

	err = dns_create_rrec(mem_ctx, keyname, QTYPE_TKEY, DNS_CLASS_ANY, 0,
			      buf->offset, buf->data, prec);

 error:
	TALLOC_FREE(buf);
	return err;
}

DNS_ERROR dns_unmarshall_tkey_record(TALLOC_CTX *mem_ctx, struct dns_rrec *rec,
				     struct dns_tkey_record **ptkey)
{
	struct dns_tkey_record *tkey;
	struct dns_buffer buf;
	uint32 tmp_inception, tmp_expiration;
	
	if (!(tkey = talloc(mem_ctx, struct dns_tkey_record))) {
		return ERROR_DNS_NO_MEMORY;
	}

	buf.data = rec->data;
	buf.size = rec->data_length;
	buf.offset = 0;
	buf.error = ERROR_DNS_SUCCESS;

	dns_unmarshall_domain_name(tkey, &buf, &tkey->algorithm);
	dns_unmarshall_uint32(&buf, &tmp_inception);
	dns_unmarshall_uint32(&buf, &tmp_expiration);
	dns_unmarshall_uint16(&buf, &tkey->mode);
	dns_unmarshall_uint16(&buf, &tkey->error);
	dns_unmarshall_uint16(&buf, &tkey->key_length);

	if (!ERR_DNS_IS_OK(buf.error)) goto error;

	if (tkey->key_length) {
		if (!(tkey->key = TALLOC_ARRAY(tkey, uint8, tkey->key_length))) {
			buf.error = ERROR_DNS_NO_MEMORY;
			goto error;
		}
	} else {
		tkey->key = NULL;
	}

	dns_unmarshall_buffer(&buf, tkey->key, tkey->key_length);
	if (!ERR_DNS_IS_OK(buf.error)) goto error;

	tkey->inception = (time_t)tmp_inception;
	tkey->expiration = (time_t)tmp_expiration;

	*ptkey = tkey;
	return ERROR_DNS_SUCCESS;

 error:
	TALLOC_FREE(tkey);
	return buf.error;
}

DNS_ERROR dns_create_tsig_record(TALLOC_CTX *mem_ctx, const char *keyname,
				 const char *algorithm_name,
				 time_t time_signed, uint16 fudge,
				 uint16 mac_length, const uint8 *mac,
				 uint16 original_id, uint16 error,
				 struct dns_rrec **prec)
{
	struct dns_buffer *buf;
	struct dns_domain_name *algorithm;
	DNS_ERROR err;

	if (!(buf = dns_create_buffer(mem_ctx))) {
		return ERROR_DNS_NO_MEMORY;
	}

	err = dns_domain_name_from_string(buf, algorithm_name, &algorithm);
	if (!ERR_DNS_IS_OK(err)) goto error;

	dns_marshall_domain_name(buf, algorithm);
	dns_marshall_uint16(buf, 0); /* time prefix */
	dns_marshall_uint32(buf, time_signed);
	dns_marshall_uint16(buf, fudge);
	dns_marshall_uint16(buf, mac_length);
	dns_marshall_buffer(buf, mac, mac_length);
	dns_marshall_uint16(buf, original_id);
	dns_marshall_uint16(buf, error);
	dns_marshall_uint16(buf, 0); /* Other Size */

	if (!ERR_DNS_IS_OK(buf->error)) {
		err = buf->error;
		goto error;
	}

	err = dns_create_rrec(mem_ctx, keyname, QTYPE_TSIG, DNS_CLASS_ANY, 0,
			      buf->offset, buf->data, prec);

 error:
	TALLOC_FREE(buf);
	return err;
}

DNS_ERROR dns_add_rrec(TALLOC_CTX *mem_ctx, struct dns_rrec *rec,
		       uint16 *num_records, struct dns_rrec ***records)
{
	struct dns_rrec **new_records;

	if (!(new_records = TALLOC_REALLOC_ARRAY(mem_ctx, *records,
						 struct dns_rrec *,
						 (*num_records)+1))) {
		return ERROR_DNS_NO_MEMORY;
	}

	new_records[*num_records] = talloc_move(new_records, &rec);

	*num_records += 1;
	*records = new_records;
	return ERROR_DNS_SUCCESS;
}

/*
 * Create a request that probes a server whether the list of IP addresses
 * provides meets our expectations
 */

DNS_ERROR dns_create_probe(TALLOC_CTX *mem_ctx, const char *zone,
			   const char *host, int num_ips,
			   const struct in_addr *iplist,
			   struct dns_update_request **preq)
{
	struct dns_update_request *req;
	struct dns_rrec *rec;
	DNS_ERROR err;
	uint16 i;

	err = dns_create_update(mem_ctx, zone, &req);
	if (!ERR_DNS_IS_OK(err)) goto error;

	err = dns_create_name_not_in_use_record(req, host, QTYPE_CNAME,	&rec);
	if (!ERR_DNS_IS_OK(err)) goto error;

	err = dns_add_rrec(req, rec, &req->num_preqs, &req->preqs);
	if (!ERR_DNS_IS_OK(err)) goto error;

	for (i=0; i<num_ips; i++) {
		err = dns_create_name_in_use_record(req, host,
						    &iplist[i], &rec);
		if (!ERR_DNS_IS_OK(err)) goto error;

		err = dns_add_rrec(req, rec, &req->num_preqs, &req->preqs);
		if (!ERR_DNS_IS_OK(err)) goto error;
	}

	*preq = req;
	return ERROR_DNS_SUCCESS;

 error:
	TALLOC_FREE(req);
	return err;
}

/* Create a PTR-record update request. */
DNS_ERROR dns_create_update_request_ptr(TALLOC_CTX *mem_ctx,
				    const char *hostname,
				    const char *zone_name,
				    const struct in_addr ip,
				    struct dns_update_request **preq)
{
	struct dns_update_request *req;
	struct dns_rrec *rec;
	DNS_ERROR err;

	char * ptr_name;

	ptr_name = talloc_asprintf(mem_ctx, "%d.%d.%d.%d.in-addr.arpa.",
		(ntohl(ip.s_addr) & 0x000000ff),
		(ntohl(ip.s_addr) & 0x0000ff00) >> 8,
		(ntohl(ip.s_addr) & 0x00ff0000) >> 16,
		(ntohl(ip.s_addr) & 0xff000000) >> 24);

	err = dns_create_update(mem_ctx, zone_name, &req);
	if (!ERR_DNS_IS_OK(err)) return err;

	err = dns_create_rrec(req, zone_name, QTYPE_ANY,
		DNS_CLASS_ANY, 0, 0, NULL, &rec);
	if (!ERR_DNS_IS_OK(err)) goto error;

	err = dns_add_rrec(req, rec, &req->num_preqs, &req->preqs);
	if (!ERR_DNS_IS_OK(err)) goto error;

	/* Delete any PTR records. */
	err = dns_create_delete_record(req, ptr_name, QTYPE_PTR, DNS_CLASS_ANY,
				       &rec);
	if (!ERR_DNS_IS_OK(err)) goto error;

	err = dns_add_rrec(req, rec, &req->num_updates, &req->updates);
	if (!ERR_DNS_IS_OK(err)) goto error;

	/* Add the corresponding PTR record. */
	err = dns_create_ptr_record(req, hostname, 3600, ip, &rec);
	if (!ERR_DNS_IS_OK(err)) goto error;

	err = dns_add_rrec(req, rec, &req->num_updates, &req->updates);
	if (!ERR_DNS_IS_OK(err)) goto error;

	*preq = req;
	return ERROR_DNS_SUCCESS;

 error:
	TALLOC_FREE(req);
	return err;
}

/* Create an A-record update request. */
DNS_ERROR dns_create_update_request_a(TALLOC_CTX *mem_ctx,
				    const char *domainname,
				    const char *hostname,
				    const struct in_addr *ip_addrs,
				    size_t num_addrs,
				    struct dns_update_request **preq)
{
	struct dns_update_request *req;
	struct dns_rrec *rec;
	DNS_ERROR err;
	size_t i;	

	err = dns_create_update(mem_ctx, domainname, &req);
	if (!ERR_DNS_IS_OK(err)) return err;

	/*
	 * The zone must be used at all
	 */

	err = dns_create_rrec(req, domainname, QTYPE_ANY, DNS_CLASS_ANY,
			      0, 0, NULL, &rec);
	if (!ERR_DNS_IS_OK(err)) goto error;

	err = dns_add_rrec(req, rec, &req->num_preqs, &req->preqs);
	if (!ERR_DNS_IS_OK(err)) goto error;

	/*
	 * Delete any existing A records
	 */

	err = dns_create_delete_record(req, hostname, QTYPE_A, DNS_CLASS_ANY,
				       &rec);
	if (!ERR_DNS_IS_OK(err)) goto error;
	
	err = dns_add_rrec(req, rec, &req->num_updates, &req->updates);
	if (!ERR_DNS_IS_OK(err)) goto error;

	/*
	 * .. and add our IPs
	 */

	/*
	 * .. and add our IPs
	 */

	for ( i=0; i<num_addrs; i++ ) {		

		if ((ntohl(ip_addrs[i].s_addr) & (uint32_t)0x7f000000) ==
		    (uint32_t)0x7f000000) {
			/* Skip anything in the 127.*.*.* network. */
			continue;
		}

		/* Add our A record. */
		err = dns_create_a_record(req, hostname, 3600, ip_addrs[i], &rec);
		if (!ERR_DNS_IS_OK(err)) 
			goto error;

		err = dns_add_rrec(req, rec, &req->num_updates, &req->updates);
		if (!ERR_DNS_IS_OK(err)) 
			goto error;
	}	

	*preq = req;
	return ERROR_DNS_SUCCESS;

 error:
	TALLOC_FREE(req);
	return err;
}