<title>Subnet and Prefix Delegation Pools</title>
<para>
Subnets may also be configured to delegate prefixes, as defined in
- <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://tools.ietf.org/html/rfc3633">RFC 3633</link>. A
- subnet may have one or more prefix delegation pools. Each pool has a
- prefixed address, which is specified as a prefix
+ <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://tools.ietf.org/html/rfc8415">RFC 8415</link>,
+ section 6.3. A subnet may have one or more prefix delegation pools.
+ Each pool has a prefixed address, which is specified as a prefix
(<command>prefix</command>) and a prefix length
(<command>prefix-len</command>), as well as a delegated prefix length
(<command>delegated-len</command>). The delegated length must not be
if (leases.empty()) {
// The server wasn't able allocate new lease and renew an existing
- // lease. In that case, the server sends NoAddrsAvail per RFC7550.
+ // lease. In that case, the server sends NoAddrsAvail per RFC 8415.
ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
STATUS_NoAddrsAvail,
"Sorry, no addresses could be"
if (leases.empty()) {
// The server wasn't able allocate new lease and renew an existing
- // lease. In that case, the server sends NoPrefixAvail per RFC7550.
+ // lease. In that case, the server sends NoPrefixAvail per RFC 8415.
ia_rsp->addOption(createStatusCode(*query, *ia_rsp,
STATUS_NoPrefixAvail,
"Sorry, no prefixes could be"
/// This function is called by the logic which processes Renew and Rebind
/// messages to extend the lifetime of the existing prefix.
///
- /// The behavior of this function is different in that when there is no
- /// binding found in the lease database for the particular client the
- /// NoBinding status code is returned when processing Renew, the exception
- /// is thrown when there is no binding and the Rebind message is processed
- /// (see RFC3633, section 12.2. for details).
+ /// The behavior of this function is different than @c extendIA_NA in that
+ /// when there is no subnet found for the rebinding case, the Rebind message
+ /// is discarded by the server. That behavior is based on the following
+ /// statement from the RFC 8415, section 18.3.5:
+ ///
+ /// "If the server chooses to not include any IAs containing IA Address or
+ /// IA Prefix options with lifetimes of 0 and the server does not include
+ /// any other IAs with leases and/or status codes, the server does not send
+ /// a Reply message. In this situation, the server discards the Rebind
+ /// message".
+ ///
+ /// @todo We should consider unification of the server behavior for address
+ /// assignment and prefix delegation with respect to Rebind message
+ /// processing. The RFC 8415, section 18.3.5 doesn't really differentiate
+ /// between IA_NA and IA_PD in how they should be processed by the server.
+ /// The intention of the spec is as follows:
+ ///
+ /// - If the server finds a lease but addresses and/or prefixes are not
+ /// appropriate anymore, it sends them with zero lifetimes.
+ /// - If the server doesn't find a lease the server checks if the addresses
+ /// and/or prefixes the client sends are appropriate and sends them back
+ /// with zero lifetimes if they aren't.
+ /// - The server may choose to not respond at all, if it cannot determine
+ /// whether the addresses and/or prefixes are appropriate and it doesn't
+ /// allocate any other addresses and/or prefixes.
+ /// - If the server cannot find the leases included in the Rebind, the
+ /// server may either allocate the leases or simply return NoBinding.
+ ///
+ /// The @c extendIA_PD function drops the Rebind message if it cannot find
+ /// the client entry (as a result of not finding a subnet for the client),
+ /// the @c extendIA_NA function sends NoBinding status code in that case.
+ /// Perhaps we should introduce an "Authoritative" configuration flag which,
+ /// if enabled, would cause the server to always respond, either indicating
+ /// that the address/prefix is inappropriate (with zero lifetimes) or that
+ /// there is no binding (NoBinding status code) for both addresses and
+ /// prefixes. When the "Authoritative" flag is disabled the server would
+ /// drop the Rebind for which there is neither subnet selected nor client
+ /// entry found (as it could be handled by another DHCP server). If nothing
+ /// else we could consider unifying the behavior of @c extendIA_NA and
+ /// @c extendIA_PD with respect to Rebind processing.
///
/// @param query client's message
/// @param ctx client context (contains subnet, duid and other parameters)
copyIAsFromLeases(query);
// During the Renew the client may request additional bindings per
- // RFC7550.
+ // RFC 8415.
appendRequestedIAs(query);
// Add Client FQDN if configured.
copyIAsFromLeases(query);
// During the Rebind the client may request additional bindings per
- // RFC7550.
+ // RFC 8415.
appendRequestedIAs(query);
// Add Client FQDN if configured.
///
/// This method is typically called to specify IA_NA options to be
/// sent to the server during 4-way handshakes and during lease
- /// renewal to request allocation of new leases (as per RFC7550).
+ /// renewal to request allocation of new leases (as per RFC 8415).
///
/// @param iaid IAID.
/// @param address IPv6 address to be included in the IA_NA. It defaults
///
/// This method is typically called to specify IA_PD options to be
/// sent to the server during 4-way handshakes and during lease
- /// renewal to request allocation of new leases (as per RFC7550).
+ /// renewal to request allocation of new leases (as per RFC 8415).
///
/// @param iaid IAID.
/// @param prefix_len Prefix length.
client.config_.leases_[0].addr_ = IOAddress("2001:db8:1:10::");
// Try to Rebind. The client will use correct IAID but will specify a
// wrong prefix. The server will discover that the client has a binding
- // but the prefix will not match. According to the RFC3633, section 12.2.
- // the server has to return the lease with lifetimes set to 0, when there
- // is a binding for the client but the prefix doesn't match.
+ // but the prefix will not match. According to the RFC 8415, section 18.3.5
+ // the server may return delegated prefix with lifetime of 0 when it
+ // finds that the lease entry for the particular IAID but the prefix
+ // is not appropriate. This constitues explicit notification to the
+ // client to not use this prefix.
ASSERT_NO_THROW(client.doRebind());
// Make sure that the server has discarded client's message. In such case,
// the message sent back to the client should be NULL.
D6O_SIP_SERVERS_ADDR = 22, /* RFC3319 */
D6O_NAME_SERVERS = 23, /* RFC3646 */
D6O_DOMAIN_SEARCH = 24, /* RFC3646 */
- D6O_IA_PD = 25, /* RFC3633 */
- D6O_IAPREFIX = 26, /* RFC3633 */
+ D6O_IA_PD = 25, /* RFC8415 */
+ D6O_IAPREFIX = 26, /* RFC8415 */
D6O_NIS_SERVERS = 27, /* RFC3898 */
D6O_NISP_SERVERS = 28, /* RFC3898 */
D6O_NIS_DOMAIN_NAME = 29, /* RFC3898 */
D6O_NISP_DOMAIN_NAME = 30, /* RFC3898 */
D6O_SNTP_SERVERS = 31, /* RFC4075 */
- D6O_INFORMATION_REFRESH_TIME = 32, /* RFC4242 */
+ D6O_INFORMATION_REFRESH_TIME = 32, /* RFC8415 */
D6O_BCMCS_SERVER_D = 33, /* RFC4280 */
D6O_BCMCS_SERVER_A = 34, /* RFC4280 */
// 35 is unassigned
D6O_CLIENT_LINKLAYER_ADDR = 79, /* RFC6939 */
D6O_LINK_ADDRESS = 80, /* RFC6977 */
// D6O_RADIUS = 81, /* RFC7037 */
- D6O_SOL_MAX_RT = 82, /* RFC7083 */
- D6O_INF_MAX_RT = 83, /* RFC7083 */
+ D6O_SOL_MAX_RT = 82, /* RFC8415 */
+ D6O_INF_MAX_RT = 83, /* RFC8415 */
// D6O_ADDRSEL = 84, /* RFC7078 */
// D6O_ADDRSEL_TABLE = 85, /* RFC7078 */
// D6O_V6_PCP_SERVER = 86, /* RFC7291 */
*/
#define DUID_TIME_EPOCH 946684800
-/* Information-Request Time option (RFC 4242) */
+/* Information-Request Time option (RFC 8415) */
#define IRT_DEFAULT 86400
#define IRT_MINIMUM 600
projects / thirdparty / kea.git / commitdiff
