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| -rw-r--r-- | src/bin/d2/nc_remove.h | 429 |
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diff --git a/src/bin/d2/nc_remove.h b/src/bin/d2/nc_remove.h new file mode 100644 index 0000000..672a3d9 --- /dev/null +++ b/src/bin/d2/nc_remove.h @@ -0,0 +1,429 @@ +// Copyright (C) 2013-2021 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. + +#ifndef NC_REMOVE_H +#define NC_REMOVE_H + +/// @file nc_remove.h This file defines the class NameRemoveTransaction. + +#include <d2srv/nc_trans.h> + +namespace isc { +namespace d2 { + +/// @brief Thrown if the NameRemoveTransaction encounters a general error. +class NameRemoveTransactionError : public isc::Exception { +public: + NameRemoveTransactionError(const char* file, size_t line, + const char* what) : + isc::Exception(file, line, what) { }; +}; + +/// @brief Embodies the "life-cycle" required to carry out a DDNS Remove update. +/// +/// NameRemoveTransaction implements a state machine for removing a forward +/// and/or reverse DNS mappings. This state machine is based upon the processing +/// logic described in RFC 4703, Section 5.5. That logic may be paraphrased as +/// follows: +/// +/// @code +/// +/// If the request includes a forward change: +/// Select a forward server +/// Send the server a request to remove client's specific forward address RR +/// If it succeeds or the server responds with name no longer in use +/// Send a server a request to delete any other RRs for that FQDN, such +/// as the DHCID RR. +/// otherwise +/// abandon the update +/// +/// If the request includes a reverse change: +/// Select a reverse server +/// Send a server a request to delete reverse entry (PTR RR) +/// +/// @endcode +/// +/// This class derives from NameChangeTransaction from which it inherits +/// states, events, and methods common to NameChangeRequest processing. +class NameRemoveTransaction : public NameChangeTransaction { +public: + + //@{ Additional states needed for NameRemove state model. + /// @brief State that attempts to remove specific forward address record. + static const int REMOVING_FWD_ADDRS_ST = NCT_DERIVED_STATE_MIN + 1; + + /// @brief State that attempts to remove any other forward RRs for the DHCID + static const int REMOVING_FWD_RRS_ST = NCT_DERIVED_STATE_MIN + 2; + + /// @brief State that attempts to remove reverse PTR records + static const int REMOVING_REV_PTRS_ST = NCT_DERIVED_STATE_MIN + 3; + //@} + + //@{ Additional events needed for NameRemove state model. + /// @brief Event sent when replace attempt to fails with address not in use. + /// @todo Currently none have been identified. + //@} + + /// @brief Constructor + /// + /// Instantiates an Remove transaction that is ready to be started. + /// + /// @param io_service IO service to be used for IO processing + /// @param ncr is the NameChangeRequest to fulfill + /// @param forward_domain is the domain to use for forward DNS updates + /// @param reverse_domain is the domain to use for reverse DNS updates + /// @param cfg_mgr pointer to the configuration manager + /// + /// @throw NameRemoveTransaction error if given request is not a CHG_REMOVE, + /// NameChangeTransaction error for base class construction errors. + NameRemoveTransaction(asiolink::IOServicePtr& io_service, + dhcp_ddns::NameChangeRequestPtr& ncr, + DdnsDomainPtr& forward_domain, + DdnsDomainPtr& reverse_domain, + D2CfgMgrPtr& cfg_mgr); + + /// @brief Destructor + virtual ~NameRemoveTransaction(); + +protected: + /// @brief Adds events defined by NameRemoveTransaction to the event set. + /// + /// Invokes NameChangeTransaction's implementation and then defines the + /// events unique to NCR Remove transaction processing. + /// + /// @throw StateModelError if an event definition is invalid or a duplicate. + virtual void defineEvents(); + + /// @brief Validates the contents of the set of events. + /// + /// Invokes NameChangeTransaction's implementation and then verifies the + /// Remove transaction's events. This tests that the needed events are in + /// the event dictionary. + /// + /// @throw StateModelError if an event value is undefined. + virtual void verifyEvents(); + + /// @brief Adds states defined by NameRemoveTransaction to the state set. + /// + /// Invokes NameChangeTransaction's implementation and then defines the + /// states unique to NCR Remove transaction processing. + /// + /// @throw StateModelError if an state definition is invalid or a duplicate. + virtual void defineStates(); + + /// @brief Validates the contents of the set of states. + /// + /// Invokes NameChangeTransaction's implementation and then verifies the + /// Remove transaction's states. This tests that the needed states are in + /// the state dictionary. + /// + /// @throw StateModelError if an event value is undefined. + virtual void verifyStates(); + + /// @brief State handler for READY_ST. + /// + /// Entered from: + /// - INIT_ST with next event of START_EVT + /// + /// The READY_ST is the state the model transitions into when the inherited + /// method, startTransaction() is invoked. This handler, therefore, is the + /// entry point into the state model execution. Its primary task is to + /// determine whether to start with a forward DNS change or a reverse DNS + /// change. + /// + /// Transitions to: + /// - SELECTING_FWD_SERVER_ST with next event of SERVER_SELECT_ST if request + /// includes a forward change. + /// + /// - SELECTING_REV_SERVER_ST with next event of SERVER_SELECT_ST if request + /// includes only a reverse change. + /// + /// @throw NameRemoveTransactionError if upon entry next event is not + /// START_EVT. + void readyHandler(); + + /// @brief State handler for SELECTING_FWD_SERVER_ST. + /// + /// Entered from: + /// - READY_ST with next event of SELECT_SERVER_EVT + /// - REMOVING_FWD_ADDRS_ST with next event of SERVER_IO_ERROR_EVT + /// + /// Selects the server to be used from the forward domain for the forward + /// DNS update. If next event is SELECT_SERVER_EVT the handler initializes + /// the forward domain's server selection mechanism and then attempts to + /// select the next server. If next event is SERVER_IO_ERROR_EVT then the + /// handler simply attempts to select the next server. + /// + /// Transitions to: + /// - REMOVING_FWD_ADDRS_ST with next event of SERVER_SELECTED upon + /// successful server selection + /// + /// - PROCESS_TRANS_FAILED with next event of NO_MORE_SERVERS_EVT upon + /// failure to select a server + /// + /// @throw NameRemoveTransactionError if upon entry next event is not + /// SELECT_SERVER_EVT or SERVER_IO_ERROR_EVT. + void selectingFwdServerHandler(); + + /// @brief State handler for SELECTING_REV_SERVER_ST. + /// + /// Entered from: + /// - READY_ST with next event of SELECT_SERVER_EVT + /// - REMOVING_FWD_RRS_ST with next event of SELECT_SERVER_EVT + /// - REMOVING_REV_PTRS_ST with next event of SERVER_IO_ERROR_EVT + /// + /// Selects the server to be used from the reverse domain for the reverse + /// DNS update. If next event is SELECT_SERVER_EVT the handler initializes + /// the reverse domain's server selection mechanism and then attempts to + /// select the next server. If next event is SERVER_IO_ERROR_EVT then the + /// handler simply attempts to select the next server. + /// + /// Transitions to: + /// - REMOVING_REV_PTRS_ST with next event of SERVER_SELECTED upon + /// successful server selection + /// + /// - PROCESS_TRANS_FAILED with next event of NO_MORE_SERVERS_EVT upon + /// failure to select a server + /// + /// @throw NameRemoveTransactionError if upon entry next event is not + /// SELECT_SERVER_EVT or SERVER_IO_ERROR_EVT. + void selectingRevServerHandler(); + + /// @brief State handler for REMOVING_FWD_ADDRS_ST. + /// + /// Entered from: + /// - SELECTING_FWD_SERVER with next event of SERVER_SELECTED_EVT + /// + /// Attempts to remove the forward DNS entry for a given FQDN, provided + /// a DHCID RR exists which matches the requesting DHCID. If this is + /// first invocation of the handler after transitioning into this state, + /// any previous update request context is deleted. If next event + /// is SERVER_SELECTED_EVT, the handler builds the forward remove request, + /// schedules an asynchronous send via sendUpdate(), and returns. Note + /// that sendUpdate will post NOP_EVT as next event. + /// + /// Posting the NOP_EVT will cause runModel() to suspend execution of + /// the state model thus affecting a "wait" for the update IO to complete. + /// Update completion occurs via the DNSClient callback operator() method + /// inherited from NameChangeTransaction. When invoked this callback will + /// post a next event of IO_COMPLETED_EVT and then invoke runModel which + /// resumes execution of the state model. + /// + /// When the handler is invoked with a next event of IO_COMPLETED_EVT, + /// the DNS update status is checked and acted upon accordingly: + /// + /// Transitions to: + /// - REMOVING_FWD_RRS_ST with next event of UPDATE_OK_EVT upon successful + /// removal or RCODE of indication FQDN is no longer in use (NXDOMAIN). + /// + /// - PROCESS_TRANS_FAILED_ST with next event of UPDATE_FAILED_EVT if the + /// DNS server rejected the update for any reason or the IO completed + /// with an unrecognized status. + /// + /// - RE-ENTER this state with next event of SERVER_SELECTED_EVT if + /// there was an IO error communicating with the server and the number of + /// per server retries has not been exhausted. + /// + /// - SELECTING_FWD_SERVER_ST with next event of SERVER_IO_ERROR_EVT if + /// there was an IO error communicating with the server and the number of + /// per server retries has been exhausted. + /// + /// @throw NameRemoveTransactionError if upon entry next event is not + /// SERVER_SELECTED_EVT or IO_COMPLETE_EVT + void removingFwdAddrsHandler(); + + /// @brief State handler for REMOVING_FWD_RRS_ST. + /// + /// Entered from: + /// - REMOVING_FWD_ADDRS_ST with next event of UPDATE_OK_EVT + /// + /// Attempts to delete any remaining RRs associated with the given FQDN + /// such as the DHCID RR. If this is first invocation of the handler after + /// transitioning into this state, any previous update request context is + /// deleted and the handler builds the forward remove request. It then + /// schedules an asynchronous send via sendUpdate(), + /// and returns. Note that sendUpdate will post NOP_EVT as the next event. + /// + /// Posting the NOP_EVT will cause runModel() to suspend execution of + /// the state model thus affecting a "wait" for the update IO to complete. + /// Update completion occurs via the DNSClient callback operator() method + /// inherited from NameChangeTransaction. When invoked this callback will + /// post a next event of IO_COMPLETED_EVT and then invoke runModel which + /// resumes execution of the state model. + /// + /// When the handler is invoked with a next event of IO_COMPLETED_EVT, + /// the DNS update status is checked and acted upon accordingly: + /// + /// Transitions to: + /// - SELECTING_REV_SERVER_ST with a next event of SELECT_SERVER_EVT upon + /// successful completion and the request includes a reverse DNS update. + /// + /// - PROCESS_TRANS_OK_ST with next event of UPDATE_OK_EVT upon successful + /// completion and the request does not include a reverse DNS update. + /// + /// - PROCESS_TRANS_FAILED_ST with a next event of UPDATE_FAILED_EVT if the + /// DNS server rejected the update for any other reason or the IO completed + /// with an unrecognized status. + /// + /// - RE-ENTER this state with a next event of SERVER_SELECTED_EVT if + /// there was an IO error communicating with the server and the number of + /// per server retries has not been exhausted. + /// + /// - PROCESS_TRANS_FAILED_ST with a next event of SERVER_IO_ERROR_EVT if + /// there we have reached maximum number of retries without success on the + /// current server. + /// + /// @note If we exhaust the IO retries for the current server due to IO + /// failures, we will abort the remaining updates. The rational is that + /// we are only in this state, if the remove of the forward address RR + /// succeeded (removingFwdAddrsHandler) on the current server so we should + /// not attempt another removal on a different server. This is perhaps a + /// point for discussion. @todo Should we go ahead with the reverse remove? + /// + /// @throw NameRemoveTransactionError if upon entry next event is not: + /// UPDATE_OK_EVT or IO_COMPLETE_EVT + void removingFwdRRsHandler(); + + /// @brief State handler for REMOVING_REV_PTRS_ST. + /// + /// Entered from: + /// - SELECTING_REV_SERVER_ST with a next event of SERVER_SELECTED_EVT + /// + /// Attempts to delete a reverse DNS entry for a given FQDN. If this is + /// first invocation of the handler after transitioning into this state, + /// any previous update request context is deleted. If next event is + /// SERVER_SELECTED_EVT, the handler builds the reverse remove request, + /// schedules an asynchronous send via sendUpdate(), and then returns. + /// Note that sendUpdate will post NOP_EVT as next event. + /// + /// Posting the NOP_EVT will cause runModel() to suspend execution of + /// the state model thus affecting a "wait" for the update IO to complete. + /// Update completion occurs via the DNSClient callback operator() method + /// inherited from NameChangeTransaction. When invoked this callback will + /// post a next event of IO_COMPLETED_EVT and then invoke runModel which + /// resumes execution of the state model. + /// + /// When the handler is invoked with a next event of IO_COMPLETED_EVT, + /// the DNS update status is checked and acted upon accordingly: + /// + /// Transitions to: + /// - PROCESS_TRANS_OK_ST with a next event of UPDATE_OK_EVT upon + /// successful completion. + /// + /// - PROCESS_TRANS_FAILED_ST with a next event of UPDATE_FAILED_EVT If the + /// DNS server rejected the update for any reason or the IO completed + /// with an unrecognized status. + /// + /// - RE-ENTER this state with a next event of SERVER_SELECTED_EVT if + /// there was an IO error communicating with the server and the number of + /// per server retries has not been exhausted. + /// + /// - SELECTING_REV_SERVER_ST with next event of SERVER_IO_ERROR_EVT if + /// there was an IO error communicating with the server and the number of + /// per server retries has been exhausted. + /// + /// @throw NameRemoveTransactionError if upon entry next event is not: + /// SERVER_SELECTED_EVT or IO_COMPLETED_EVT + void removingRevPtrsHandler(); + + /// @brief State handler for PROCESS_TRANS_OK_ST. + /// + /// Entered from: + /// - REMOVING_FWD_RRS_ST with a next event of UPDATE_OK_EVT + /// - REMOVING_REV_PTRS_ST with a next event of UPDATE_OK_EVT + /// + /// Sets the transaction action status to indicate success and ends + /// model execution. + /// + /// Transitions to: + /// - END_ST with a next event of END_EVT. + /// + /// @throw NameRemoveTransactionError if upon entry next event is not: + /// UPDATE_OK_EVT + void processRemoveOkHandler(); + + /// @brief State handler for PROCESS_TRANS_FAILED_ST. + /// + /// Entered from: + /// - SELECTING_FWD_SERVER_ST with a next event of NO_MORE_SERVERS + /// - REMOVING_FWD_ADDRS_ST with a next event of UPDATE_FAILED_EVT + /// - REMOVING_FWD_RRS_ST with a next event of UPDATE_FAILED_EVT + /// - REMOVING_FWD_RRS_ST with a next event of SERVER_IO_ERROR_EVT + /// - SELECTING_REV_SERVER_ST with a next event of NO_MORE_SERVERS + /// - REMOVING_REV_PTRS_ST with a next event of UPDATE_FAILED_EVT + /// + /// Sets the transaction status to indicate failure and ends + /// model execution. + /// + /// Transitions to: + /// - END_ST with a next event of FAIL_EVT. + /// + /// @throw NameRemoveTransactionError if upon entry next event is not: + /// UPDATE_FAILED_EVT + void processRemoveFailedHandler(); + + /// @brief Builds a DNS request to remove a forward DNS address for a FQDN. + /// + /// Constructs a DNS update request, based upon the NCR, for removing a + /// forward DNS address mapping. Once constructed, the request is stored as + /// the transaction's DNS update request. + /// + /// The request content is adherent to RFC 4703 section 5.5, paragraph 4. + /// + /// Prerequisite RRsets: + /// 1. An assertion that a matching DHCID RR exists + /// + /// Updates RRsets: + /// 1. A delete of the FQDN/IP RR (type A for IPv4, AAAA for IPv6) + /// + /// @throw This method does not throw but underlying methods may. + void buildRemoveFwdAddressRequest(); + + /// @brief Builds a DNS request to remove all forward DNS RRs for a FQDN. + /// + /// Constructs a DNS update request, based upon the NCR, for removing any + /// remaining forward DNS RRs, once all A or AAAA entries for the FQDN + /// have been removed. Once constructed, the request is stored as the + /// transaction's DNS update request. + /// + /// The request content is adherent to RFC 4703 section 5.5, paragraph 5. + /// + /// Prerequisite RRsets: + /// 1. An assertion that a matching DHCID RR exists + /// 2. An assertion that no A RRs for the FQDN exist + /// 3. An assertion that no AAAA RRs for the FQDN exist + /// + /// Updates RRsets: + /// 1. A delete of all RRs for the FQDN + /// + /// @throw This method does not throw but underlying methods may. + void buildRemoveFwdRRsRequest(); + + /// @brief Builds a DNS request to remove a reverse DNS entry for a FQDN + /// + /// Constructs a DNS update request, based upon the NCR, for removing a + /// reverse DNS mapping. Once constructed, the request is stored as + /// the transaction's DNS update request. + /// + /// The request content is adherent to RFC 4703 section 5.5, paragraph 2: + /// + /// Prerequisite RRsets: + /// 1. An assertion that a PTR record matching the client's FQDN exists. + /// + /// Updates RRsets: + /// 1. A delete of all RRs for the FQDN + /// + /// @throw This method does not throw but underlying methods may. + void buildRemoveRevPtrsRequest(); +}; + +/// @brief Defines a pointer to a NameRemoveTransaction. +typedef boost::shared_ptr<NameRemoveTransaction> NameRemoveTransactionPtr; + + +} // namespace isc::d2 +} // namespace isc +#endif |