Domain Name Service subroutines. */
/*
- * Copyright (c) 2000 Internet Software Consortium.
+ * Copyright (c) 2001 Internet Software Consortium.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
#ifndef lint
static char copyright[] =
-"$Id: dns.c,v 1.35 2001/02/22 07:37:13 mellon Exp $ Copyright (c) 2000 The Internet Software Consortium. All rights reserved.\n";
+"$Id: dns.c,v 1.36 2001/06/27 00:29:46 mellon Exp $ Copyright (c) 2001 The Internet Software Consortium. All rights reserved.\n";
#endif /* not lint */
#include "dhcpd.h"
strlen (zone -> key -> name) > NS_MAXDNAME) ||
(!zone -> key -> algorithm ||
strlen (zone -> key -> algorithm) > NS_MAXDNAME) ||
- (!zone -> key)) {
+ (!zone -> key) ||
+ (!zone -> key -> key) ||
+ (zone -> key -> key -> len == 0)) {
return ISC_R_INVALIDKEY;
}
tkey = dmalloc (sizeof *tkey, MDL);
} else {
dns_zone_hash =
new_hash ((hash_reference)dns_zone_reference,
- (hash_dereference)dns_zone_dereference, 1);
+ (hash_dereference)dns_zone_dereference, 1,
+ MDL);
if (!dns_zone_hash)
return ISC_R_NOMEMORY;
}
isc_result_t dns_zone_lookup (struct dns_zone **zone, const char *name)
{
struct dns_zone *tz = (struct dns_zone *)0;
- unsigned len;
+ int len;
char *tname = (char *)0;
isc_result_t status;
len = strlen (name);
if (name [len - 1] != '.') {
- tname = dmalloc (len + 2, MDL);
+ tname = dmalloc ((unsigned)len + 2, MDL);
if (!tname)
return ISC_R_NOMEMORY;;
strcpy (tname, name);
dns_zone = *ptr;
*ptr = (struct dns_zone *)0;
--dns_zone -> refcnt;
- rc_register (file, line, ptr, dns_zone, dns_zone -> refcnt);
+ rc_register (file, line, ptr, dns_zone, dns_zone -> refcnt, 1);
if (dns_zone -> refcnt > 0)
return 1;
if (dns_zone -> refcnt < 0) {
log_error ("%s(%d): negative refcnt!", file, line);
#if defined (DEBUG_RC_HISTORY)
- dump_rc_history ();
+ dump_rc_history (dns_zone);
#endif
#if defined (POINTER_DEBUG)
abort ();
return ISC_R_INVALIDARG;
/* For each subzone, try to find a cached zone. */
- for (np = dname - 1; np; np = strchr (np, '.')) {
+ for (np = dname; np; np = strchr (np, '.')) {
np++;
status = dns_zone_lookup (&zone, np);
if (status == ISC_R_SUCCESS)
enter_dns_zone (zone);
}
-int get_dhcid (struct data_string *id, struct lease *lease)
+/* Have to use TXT records for now. */
+#define T_DHCID T_TXT
+
+int get_dhcid (struct data_string *id,
+ int type, const u_int8_t *data, unsigned len)
{
unsigned char buf[MD5_DIGEST_LENGTH];
MD5_CTX md5;
int i;
+ /* Types can only be 0..(2^16)-1. */
+ if (type < 0 || type > 65535)
+ return 0;
+
+ /* Hexadecimal MD5 digest plus two byte type and NUL. */
if (!buffer_allocate (&id -> buffer,
(MD5_DIGEST_LENGTH * 2) + 3, MDL))
return 0;
* M. Stapp, Y. Rekhter
*/
- MD5_Init (&md5);
-
- if (lease -> uid) {
- id -> buffer -> data [0] =
- "0123456789abcdef" [DHO_DHCP_CLIENT_IDENTIFIER >> 4];
- id -> buffer -> data [1] =
- "0123456789abcdef" [DHO_DHCP_CLIENT_IDENTIFIER % 15];
- /* Use the DHCP Client Identifier option. */
- MD5_Update (&md5, lease -> uid, lease -> uid_len);
- } else if (lease -> hardware_addr.hlen) {
- id -> buffer -> data [0] = '0';
- id -> buffer -> data [1] = '0';
- /* Use the link-layer address. */
- MD5_Update (&md5,
- lease -> hardware_addr.hbuf,
- lease -> hardware_addr.hlen);
- } else {
- /* Uh-oh. Something isn't right here. */
- return 1;
- }
+ /* Put the type in the first two bytes. */
+ id -> buffer -> data [0] = "0123456789abcdef" [type >> 4];
+ id -> buffer -> data [1] = "0123456789abcdef" [type % 15];
+ /* Mash together an MD5 hash of the identifier. */
+ MD5_Init (&md5);
+ MD5_Update (&md5, data, len);
MD5_Final (buf, &md5);
/* Convert into ASCII. */
id -> buffer -> data [id -> len] = 0;
id -> terminated = 1;
- return 0;
+ return 1;
}
+
+/* Now for the DDNS update code that is shared between client and
+ server... */
+
+isc_result_t ddns_update_a (struct data_string *ddns_fwd_name,
+ struct iaddr ddns_addr,
+ struct data_string *ddns_dhcid,
+ unsigned long ttl, int rrsetp)
+{
+ ns_updque updqueue;
+ ns_updrec *updrec;
+ isc_result_t result;
+ char ddns_address [16];
+
+ if (ddns_addr.len != 4)
+ return ISC_R_INVALIDARG;
+#ifndef NO_SNPRINTF
+ snprintf (ddns_address, 16, "%d.%d.%d.%d",
+ ddns_addr.iabuf[0], ddns_addr.iabuf[1],
+ ddns_addr.iabuf[2], ddns_addr.iabuf[3]);
+#else
+ sprintf (ddns_address, "%d.%d.%d.%d",
+ ddns_addr.iabuf[0], ddns_addr.iabuf[1],
+ ddns_addr.iabuf[2], ddns_addr.iabuf[3]);
+#endif
+
+ /*
+ * When a DHCP client or server intends to update an A RR, it first
+ * prepares a DNS UPDATE query which includes as a prerequisite the
+ * assertion that the name does not exist. The update section of the
+ * query attempts to add the new name and its IP address mapping (an A
+ * RR), and the DHCID RR with its unique client-identity.
+ * -- "Interaction between DHCP and DNS"
+ */
+
+ ISC_LIST_INIT (updqueue);
+
+ /*
+ * A RR does not exist.
+ */
+ updrec = minires_mkupdrec (S_PREREQ,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_A, 0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = (unsigned char *)0;
+ updrec -> r_size = 0;
+ updrec -> r_opcode = rrsetp ? NXRRSET : NXDOMAIN;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * Add A RR.
+ */
+ updrec = minires_mkupdrec (S_UPDATE,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_A, ttl);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = (unsigned char *)ddns_address;
+ updrec -> r_size = strlen (ddns_address);
+ updrec -> r_opcode = ADD;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * Add DHCID RR.
+ */
+ updrec = minires_mkupdrec (S_UPDATE,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_DHCID, ttl);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = ddns_dhcid -> data;
+ updrec -> r_size = ddns_dhcid -> len;
+ updrec -> r_opcode = ADD;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * Attempt to perform the update.
+ */
+ result = minires_nupdate (&resolver_state, ISC_LIST_HEAD (updqueue));
+
+ print_dns_status ((int)result, &updqueue);
+
+ while (!ISC_LIST_EMPTY (updqueue)) {
+ updrec = ISC_LIST_HEAD (updqueue);
+ ISC_LIST_UNLINK (updqueue, updrec, r_link);
+ minires_freeupdrec (updrec);
+ }
+
+
+ /*
+ * If this update operation succeeds, the updater can conclude that it
+ * has added a new name whose only RRs are the A and DHCID RR records.
+ * The A RR update is now complete (and a client updater is finished,
+ * while a server might proceed to perform a PTR RR update).
+ * -- "Interaction between DHCP and DNS"
+ */
+
+ if (result == ISC_R_SUCCESS)
+ return result;
+
+
+ /*
+ * If the first update operation fails with YXDOMAIN, the updater can
+ * conclude that the intended name is in use. The updater then
+ * attempts to confirm that the DNS name is not being used by some
+ * other host. The updater prepares a second UPDATE query in which the
+ * prerequisite is that the desired name has attached to it a DHCID RR
+ * whose contents match the client identity. The update section of
+ * this query deletes the existing A records on the name, and adds the
+ * A record that matches the DHCP binding and the DHCID RR with the
+ * client identity.
+ * -- "Interaction between DHCP and DNS"
+ */
+
+ if (result != (rrsetp ? ISC_R_YXRRSET : ISC_R_YXDOMAIN))
+ return result;
+
+
+ /*
+ * DHCID RR exists, and matches client identity.
+ */
+ updrec = minires_mkupdrec (S_PREREQ,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_DHCID, 0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = ddns_dhcid -> data;
+ updrec -> r_size = ddns_dhcid -> len;
+ updrec -> r_opcode = YXRRSET;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * Delete A RRset.
+ */
+ updrec = minires_mkupdrec (S_UPDATE,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_A, 0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = (unsigned char *)0;
+ updrec -> r_size = 0;
+ updrec -> r_opcode = DELETE;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * Add A RR.
+ */
+ updrec = minires_mkupdrec (S_UPDATE,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_A, ttl);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = (unsigned char *)ddns_address;
+ updrec -> r_size = strlen (ddns_address);
+ updrec -> r_opcode = ADD;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * Attempt to perform the update.
+ */
+ result = minires_nupdate (&resolver_state, ISC_LIST_HEAD (updqueue));
+
+ print_dns_status ((int)result, &updqueue);
+
+ /*
+ * If this query succeeds, the updater can conclude that the current
+ * client was the last client associated with the domain name, and that
+ * the name now contains the updated A RR. The A RR update is now
+ * complete (and a client updater is finished, while a server would
+ * then proceed to perform a PTR RR update).
+ * -- "Interaction between DHCP and DNS"
+ */
+
+ /*
+ * If the second query fails with NXRRSET, the updater must conclude
+ * that the client's desired name is in use by another host. At this
+ * juncture, the updater can decide (based on some administrative
+ * configuration outside of the scope of this document) whether to let
+ * the existing owner of the name keep that name, and to (possibly)
+ * perform some name disambiguation operation on behalf of the current
+ * client, or to replace the RRs on the name with RRs that represent
+ * the current client. If the configured policy allows replacement of
+ * existing records, the updater submits a query that deletes the
+ * existing A RR and the existing DHCID RR, adding A and DHCID RRs that
+ * represent the IP address and client-identity of the new client.
+ * -- "Interaction between DHCP and DNS"
+ */
+
+ error:
+ while (!ISC_LIST_EMPTY (updqueue)) {
+ updrec = ISC_LIST_HEAD (updqueue);
+ ISC_LIST_UNLINK (updqueue, updrec, r_link);
+ minires_freeupdrec (updrec);
+ }
+
+ return result;
+}
+
+isc_result_t ddns_remove_a (struct data_string *ddns_fwd_name,
+ struct iaddr ddns_addr,
+ struct data_string *ddns_dhcid)
+{
+ ns_updque updqueue;
+ ns_updrec *updrec;
+ isc_result_t result = SERVFAIL;
+ char ddns_address [16];
+
+ if (ddns_addr.len != 4)
+ return ISC_R_INVALIDARG;
+
+#ifndef NO_SNPRINTF
+ snprintf (ddns_address, 16, "%d.%d.%d.%d",
+ ddns_addr.iabuf[0], ddns_addr.iabuf[1],
+ ddns_addr.iabuf[2], ddns_addr.iabuf[3]);
+#else
+ sprintf (ddns_address, "%d.%d.%d.%d",
+ ddns_addr.iabuf[0], ddns_addr.iabuf[1],
+ ddns_addr.iabuf[2], ddns_addr.iabuf[3]);
+#endif
+
+
+ /*
+ * The entity chosen to handle the A record for this client (either the
+ * client or the server) SHOULD delete the A record that was added when
+ * the lease was made to the client.
+ *
+ * In order to perform this delete, the updater prepares an UPDATE
+ * query which contains two prerequisites. The first prerequisite
+ * asserts that the DHCID RR exists whose data is the client identity
+ * described in Section 4.3. The second prerequisite asserts that the
+ * data in the A RR contains the IP address of the lease that has
+ * expired or been released.
+ * -- "Interaction between DHCP and DNS"
+ */
+
+ ISC_LIST_INIT (updqueue);
+
+ /*
+ * DHCID RR exists, and matches client identity.
+ */
+ updrec = minires_mkupdrec (S_PREREQ,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_DHCID,0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = ddns_dhcid -> data;
+ updrec -> r_size = ddns_dhcid -> len;
+ updrec -> r_opcode = YXRRSET;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * A RR matches the expiring lease.
+ */
+ updrec = minires_mkupdrec (S_PREREQ,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_A, 0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = (unsigned char *)ddns_address;
+ updrec -> r_size = strlen (ddns_address);
+ updrec -> r_opcode = YXRRSET;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+
+ /*
+ * Delete appropriate A RR.
+ */
+ updrec = minires_mkupdrec (S_UPDATE,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_A, 0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = (unsigned char *)ddns_address;
+ updrec -> r_size = strlen (ddns_address);
+ updrec -> r_opcode = DELETE;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+ /*
+ * Attempt to perform the update.
+ */
+ result = minires_nupdate (&resolver_state, ISC_LIST_HEAD (updqueue));
+ print_dns_status ((int)result, &updqueue);
+
+ /*
+ * If the query fails, the updater MUST NOT delete the DNS name. It
+ * may be that the host whose lease on the server has expired has moved
+ * to another network and obtained a lease from a different server,
+ * which has caused the client's A RR to be replaced. It may also be
+ * that some other client has been configured with a name that matches
+ * the name of the DHCP client, and the policy was that the last client
+ * to specify the name would get the name. In this case, the DHCID RR
+ * will no longer match the updater's notion of the client-identity of
+ * the host pointed to by the DNS name.
+ * -- "Interaction between DHCP and DNS"
+ */
+
+ if (result != ISC_R_SUCCESS)
+ goto error;
+
+ while (!ISC_LIST_EMPTY (updqueue)) {
+ updrec = ISC_LIST_HEAD (updqueue);
+ ISC_LIST_UNLINK (updqueue, updrec, r_link);
+ minires_freeupdrec (updrec);
+ }
+
+ /* If the deletion of the A succeeded, and there are no A records
+ left for this domain, then we can blow away the DHCID record
+ as well. We can't blow away the DHCID record above because
+ it's possible that more than one A has been added to this
+ domain name. */
+ ISC_LIST_INIT (updqueue);
+
+ /*
+ * A RR does not exist.
+ */
+ updrec = minires_mkupdrec (S_PREREQ,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_A, 0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = (unsigned char *)0;
+ updrec -> r_size = 0;
+ updrec -> r_opcode = NXRRSET;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+ /*
+ * Delete appropriate DHCID RR.
+ */
+ updrec = minires_mkupdrec (S_UPDATE,
+ (const char *)ddns_fwd_name -> data,
+ C_IN, T_DHCID, 0);
+ if (!updrec) {
+ result = ISC_R_NOMEMORY;
+ goto error;
+ }
+
+ updrec -> r_data = ddns_dhcid -> data;
+ updrec -> r_size = ddns_dhcid -> len;
+ updrec -> r_opcode = DELETE;
+
+ ISC_LIST_APPEND (updqueue, updrec, r_link);
+
+ /*
+ * Attempt to perform the update.
+ */
+ result = minires_nupdate (&resolver_state, ISC_LIST_HEAD (updqueue));
+ print_dns_status ((int)result, &updqueue);
+
+ /* Fall through. */
+ error:
+
+ while (!ISC_LIST_EMPTY (updqueue)) {
+ updrec = ISC_LIST_HEAD (updqueue);
+ ISC_LIST_UNLINK (updqueue, updrec, r_link);
+ minires_freeupdrec (updrec);
+ }
+
+ return result;
+}
+
+
#endif /* NSUPDATE */
HASH_FUNCTIONS (dns_zone, const char *, struct dns_zone)
projects / thirdparty / dhcp.git / blobdiff