Adding upstream version 2.4.1.upstream/2.4.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 530 insertions, 0 deletions

diff --git a/src/lib/dhcpsrv/d2_client_mgr.h b/src/lib/dhcpsrv/d2_client_mgr.h
new file mode 100644
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+++ b/src/lib/dhcpsrv/d2_client_mgr.h
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+// Copyright (C) 2014-2022 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 D2_CLIENT_MGR_H
+#define D2_CLIENT_MGR_H
+
+/// @file d2_client_mgr.h Defines the D2ClientMgr class.
+/// This file defines the class Kea uses to act as a client of the
+/// kea-dhcp-ddns module (aka D2).
+///
+#include <asiolink/io_address.h>
+#include <dhcp_ddns/ncr_io.h>
+#include <dhcpsrv/d2_client_cfg.h>
+#include <dhcpsrv/srv_config.h>
+#include <exceptions/exceptions.h>
+
+#include <boost/algorithm/string.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/noncopyable.hpp>
+
+#include <stdint.h>
+#include <string>
+#include <vector>
+#include <sstream>
+
+namespace isc {
+namespace dhcp {
+
+/// @brief Defines the type for D2 IO error handler.
+/// This callback is invoked when a send to kea-dhcp-ddns completes with a
+/// failed status.  This provides the application layer (Kea) with a means to
+/// handle the error appropriately.
+///
+/// @param result Result code of the send operation.
+/// @param ncr NameChangeRequest which failed to send.
+///
+/// @note Handlers are expected not to throw. In the event a handler does
+/// throw invoking code logs the exception and then swallows it.
+typedef
+std::function<void(const dhcp_ddns::NameChangeSender::Result result,
+                   dhcp_ddns::NameChangeRequestPtr& ncr)> D2ClientErrorHandler;
+
+/// @brief D2ClientMgr isolates Kea from the details of being a D2 client.
+///
+/// Provides services for managing the current dhcp-ddns configuration and
+/// as well as communications with kea-dhcp-ddns.  Regarding configuration it
+/// provides services to store, update, and access the current dhcp-ddns
+/// configuration.  As for kea-dhcp-ddns communications, D2ClientMgr creates
+/// maintains a NameChangeSender appropriate to the current configuration and
+/// provides services to start, stop, and post NCRs to the sender.  Additionally
+/// there are methods to examine the queue of requests currently waiting for
+/// transmission.
+///
+/// The manager also provides the mechanics to integrate the ASIO-based IO
+/// used by the NCR IPC with the select-driven IO used by Kea.  Senders expose
+/// a file descriptor, the "select-fd" that can monitored for read-readiness
+/// with the select() function (or variants).  D2ClientMgr provides a method,
+/// runReadyIO(), that will instructs the sender to process the next ready
+/// ready IO handler on the sender's IOservice.  Track# 3315 extended
+/// Kea's IfaceMgr to support the registration of multiple external sockets
+/// with callbacks that are then monitored with IO readiness via select().
+/// D2ClientMgr registers the sender's select-fd and runReadyIO() with
+/// IfaceMgr when entering the send mode and unregisters it when exiting send
+/// mode.
+///
+/// To place the manager in send mode, the calling layer must supply an error
+/// handler and optionally an IOService instance.  The error handler is invoked
+/// if a send completes with a failed status. This provides the calling layer
+/// an opportunity act upon the error.
+///
+/// If the caller supplies an IOService, that service will be used to process
+/// the sender's IO.  If not supplied, D2ClientMgr pass a private IOService
+/// into the sender.  Using a private service isolates the sender's IO from
+/// any other services.
+///
+class D2ClientMgr : public dhcp_ddns::NameChangeSender::RequestSendHandler,
+                    boost::noncopyable {
+public:
+    /// @brief Constructor
+    ///
+    /// Default constructor which constructs an instance which has DHCP-DDNS
+    /// updates disabled.
+    D2ClientMgr();
+
+    /// @brief Destructor.
+    ~D2ClientMgr();
+
+    /// @brief Updates the DHCP-DDNS client configuration to the given value.
+    ///
+    /// @param new_config pointer to the new client configuration.
+    /// @throw D2ClientError if passed an empty pointer.
+    void setD2ClientConfig(D2ClientConfigPtr& new_config);
+
+    /// @brief Convenience method for checking if DHCP-DDNS is enabled.
+    ///
+    /// @return True if the D2 configuration is enabled.
+    bool ddnsEnabled();
+
+    /// @brief Fetches the DHCP-DDNS configuration pointer.
+    ///
+    /// @return a reference to the current configuration pointer.
+    const D2ClientConfigPtr& getD2ClientConfig() const;
+
+    /// @brief Determines server flags based on configuration and  client flags.
+    ///
+    /// This method uses input values for the client's FQDN S and N flags, in
+    /// conjunction with the configuration parameters updates-enabled, override-
+    /// no-updates, and override-client-updates to determine the values that
+    /// should be used for the server's FQDN S and N flags.
+    /// The logic in this method is based upon RFCs 4702 and 4704, and is
+    /// shown in the following truth table:
+    ///
+    /// @code
+    ///
+    /// When Updates are enabled:
+    ///
+    ///  ON = Override No Updates, OC = Override Client Updates
+    ///
+    ///  | Client |--------   Server Response Flags   ------------|
+    ///  | Flags  | ON=F,OC=F | ON=F,OC=T | ON=T,OC=F | ON=T,OC=T |
+    ///  |  N-S   |  N-S-O    |   N-S-O   |   N-S-O   |   N-S-O   |
+    ///  ----------------------------------------------------------
+    ///  |  0-0   |  0-0-0    |   0-1-1   |   0-0-0   |   0-1-1   |
+    ///  |  0-1   |  0-1-0    |   0-1-0   |   0-1-0   |   0-1-0   |
+    ///  |  1-0   |  1-0-0    |   1-0-0   |   0-1-1   |   0-1-1   |
+    ///
+    /// One can then use the server response flags to know when forward and
+    /// reverse updates should be performed:
+    ///
+    ///  - Forward updates should be done when the Server S-Flag is true.
+    ///  - Reverse updates should be done when the Server N-Flag is false.
+    ///
+    /// When Updates are disabled:
+    ///
+    /// | Client  | Server |
+    /// |  N-S    |  N-S-O |
+    /// --------------------
+    /// |  0-0    | 1-0-0  |
+    /// |  0-1    | 1-0-1  |
+    /// |  1-0    | 1-0-0  |
+    ///
+    /// @endcode
+    ///
+    /// @param client_s  S Flag from the client's FQDN
+    /// @param client_n  N Flag from the client's FQDN
+    /// @param server_s [out] S Flag for the server's FQDN
+    /// @param server_n [out] N Flag for the server's FQDN
+    /// @param ddns_params DDNS behavioral configuration parameters
+    ///
+    /// @throw isc::BadValue if client_s and client_n are both 1 as this is
+    /// an invalid combination per RFCs.
+    void analyzeFqdn(const bool client_s, const bool client_n, bool& server_s,
+                     bool& server_n, const DdnsParams& ddns_params) const;
+
+    /// @brief Builds a FQDN based on the configuration and given IP address.
+    ///
+    /// Using the current values for generated-prefix, qualifying-suffix and
+    /// an IP address, this method constructs a fully qualified domain name.
+    /// It supports both IPv4 and IPv6 addresses.  The format of the name
+    /// is as follows:
+    ///
+    ///     <generated-prefix>-<ip address>.<qualifying-suffix>.
+    ///
+    /// <ip-address> is the result of IOAddress.toText() with the delimiters
+    /// ('.' for IPv4 or ':' for IPv6) replaced with a hyphen, '-'.
+    ///
+    /// @param address IP address from which to derive the name (IPv4 or IPv6)
+    /// @param ddns_params DDNS behavioral configuration parameters
+    /// @param trailing_dot A boolean value which indicates whether trailing
+    /// dot should be appended (if true) or not (false).
+    ///
+    /// @return std::string containing the generated name.
+    std::string generateFqdn(const asiolink::IOAddress& address,
+                             const DdnsParams& ddns_params,
+                             const bool trailing_dot = true) const;
+
+    /// @brief Adds a qualifying suffix to a given domain name
+    ///
+    /// Constructs a FQDN based on the configured qualifying-suffix and
+    /// a partial domain name as follows:
+    ///
+    ///     <partial_name>.<qualifying-suffix>.
+    ///
+    /// Note that the qualifying suffix will only be appended if the
+    /// input name does not already end with that suffix.
+    ///
+    /// @param partial_name domain name to qualify
+    /// @param ddns_params DDNS behavioral configuration parameters
+    /// @param trailing_dot A boolean value which when true guarantees the
+    /// result will end with a "." and when false that the result will not
+    /// end with a "."   Note that this rule is applied even if the qualifying
+    /// suffix itself is empty (i.e. "").
+    ///
+    /// @return std::string containing the qualified name.
+    std::string qualifyName(const std::string& partial_name,
+                            const DdnsParams& ddns_params,
+                            const bool trailing_dot) const;
+
+    /// @brief Set server FQDN flags based on configuration and a given FQDN
+    ///
+    /// Templated wrapper around the analyzeFqdn() allowing that method to
+    /// be used for either IPv4 or IPv6 processing.  This methods resets all
+    /// of the flags in the response to zero and then sets the S,N, and O
+    /// flags.  Any other flags are the responsibility of the invoking layer.
+    ///
+    /// @param fqdn FQDN option from which to read client (inbound) flags
+    /// @param fqdn_resp FQDN option to update with the server (outbound) flags
+    /// @param ddns_params DDNS behavioral configuration parameters
+    /// @tparam T FQDN Option class containing the FQDN data such as
+    /// dhcp::Option4ClientFqdn or dhcp::Option6ClientFqdn
+    template <class T>
+    void adjustFqdnFlags(const T& fqdn, T& fqdn_resp,
+                         const DdnsParams& ddns_params);
+
+    /// @brief Get directional update flags based on server FQDN flags
+    ///
+    /// Templated convenience method which determines whether forward and
+    /// reverse updates should be performed based on a server response version
+    /// of the FQDN flags. The logic is straight forward and currently not
+    /// dependent upon configuration specific values:
+    ///
+    /// * forward will be true if S_FLAG is true
+    /// * reverse will be true if N_FLAG is false
+    ///
+    /// @param fqdn_resp FQDN option from which to read server (outbound) flags
+    /// @param [out] forward bool value will be set to true if forward updates
+    /// should be done, false if not.
+    /// @param [out] reverse bool value will be set to true if reverse updates
+    /// should be done, false if not.
+    /// @tparam T FQDN Option class containing the FQDN data such as
+    /// dhcp::Option4ClientFqdn or dhcp::Option6ClientFqdn
+    template <class T>
+    void getUpdateDirections(const T& fqdn_resp, bool& forward, bool& reverse);
+
+    /// @brief Set server FQDN name based on configuration and a given FQDN
+    ///
+    /// Templated method which adjusts the domain name value and type in
+    /// a server FQDN from a client (inbound) FQDN and the current
+    /// configuration.  The logic is as follows:
+    ///
+    /// If replace-client-name is true or the supplied name is empty, the
+    /// server FQDN is set to ""/PARTIAL.
+    ///
+    /// If replace-client-name is false and the supplied name is a partial
+    /// name the server FQDN is set to the supplied name qualified by
+    /// appending the qualifying-suffix.
+    ///
+    /// If replace-client-name is false and the supplied name is a fully
+    /// qualified name, set the server FQDN to the supplied name.
+    ///
+    /// If hostname-char-set is not empty, the inbound name will be
+    /// sanitized.  This is done by iterating over the domain name labels,
+    /// sanitizing each individually, and then concatenating them into a
+    /// new sanitized name.  It is done this way to guard against the case
+    /// where the hostname-char-set does not protect dots from replacement.
+    ///
+    /// @param fqdn FQDN option from which to get client (inbound) name
+    /// @param fqdn_resp FQDN option to update with the adjusted name
+    /// @param ddns_params DDNS behavioral configuration parameters
+    /// @tparam T  FQDN Option class containing the FQDN data such as
+    /// dhcp::Option4ClientFqdn or dhcp::Option6ClientFqdn
+    template <class T>
+    void adjustDomainName(const T& fqdn, T& fqdn_resp,
+                          const DdnsParams& ddns_params);
+
+    /// @brief Enables sending NameChangeRequests to kea-dhcp-ddns
+    ///
+    /// Places the NameChangeSender into send mode. This instructs the
+    /// sender to begin dequeuing and transmitting requests and to accept
+    /// additional requests via the sendRequest() method.
+    ///
+    /// @param error_handler application level error handler to cope with
+    /// sends that complete with a failed status.  A valid function must be
+    /// supplied as the manager cannot know how an application should deal
+    /// with send failures.
+    /// @param io_service IOService to be used for sender IO event processing
+    /// @warning It is up to the invoking layer to ensure the io_service
+    /// instance used outlives the D2ClientMgr send mode. When the send mode
+    /// is exited, either explicitly by calling stopSender() or implicitly
+    /// through D2ClientMgr destruction, any ASIO objects such as sockets or
+    /// timers will be closed and released.  If the io_service goes out of scope
+    /// first this behavior could be unpredictable.
+    ///
+    /// @throw D2ClientError if sender instance is null. Underlying layer
+    /// may throw NCRSenderExceptions exceptions.
+    void startSender(D2ClientErrorHandler error_handler,
+                     isc::asiolink::IOService& io_service);
+
+    /// @brief Enables sending NameChangeRequests to kea-dhcp-ddns
+    ///
+    /// Places the NameChangeSender into send mode. This instructs the
+    /// sender to begin dequeuing and transmitting requests and to accept
+    /// additional requests via the sendRequest() method.  The manager
+    /// will create a new, private instance of an IOService for the sender
+    /// to use for IO event processing.
+    ///
+    /// @param error_handler application level error handler to cope with
+    /// sends that complete with a failed status.  A valid function must be
+    /// supplied as the manager cannot know how an application should deal
+    /// with send failures.
+    ///
+    /// @throw D2ClientError if sender instance is null. Underlying layer
+    /// may throw NCRSenderExceptions exceptions.
+    void startSender(D2ClientErrorHandler error_handler);
+
+    /// @brief Returns true if the sender is in send mode, false otherwise.
+    ///
+    /// A true value indicates that the sender is present and in accepting
+    /// messages for transmission, false otherwise.
+    bool amSending() const;
+
+    /// @brief Disables sending NameChangeRequests to kea-dhcp-ddns
+    ///
+    /// Takes the NameChangeSender out of send mode.  The sender will stop
+    /// transmitting requests, though any queued requests remain queued.
+    /// Attempts to queue additional requests via sendRequest will fail.
+    ///
+    /// @throw D2ClientError if sender instance is null. Underlying layer
+    /// may throw NCRSenderExceptions exceptions.
+    void stopSender();
+
+    /// @brief Send the given NameChangeRequests to kea-dhcp-ddns
+    ///
+    /// Passes NameChangeRequests to the NCR sender for transmission to
+    /// kea-dhcp-ddns. If the sender rejects the message, the client's error
+    /// handler will be invoked.  The most likely cause for rejection is
+    /// the senders' queue has reached maximum capacity.
+    ///
+    /// @param ncr NameChangeRequest to send
+    ///
+    /// @throw D2ClientError if sender instance is null or not in send
+    /// mode.  Either of these represents a programmatic error.
+    void sendRequest(dhcp_ddns::NameChangeRequestPtr& ncr);
+
+    /// @brief Calls the client's error handler.
+    ///
+    /// Calls the error handler method set by startSender() when an
+    /// error occurs attempting to send a method.  If the error handler
+    /// throws an exception it will be caught and logged.
+    ///
+    /// @param result contains that send outcome status.
+    /// @param ncr is a pointer to the NameChangeRequest that was attempted.
+    ///
+    /// This method is exception safe.
+    void invokeClientErrorHandler(const dhcp_ddns::NameChangeSender::
+                                  Result result,
+                                  dhcp_ddns::NameChangeRequestPtr& ncr);
+
+    /// @brief Returns the number of NCRs queued for transmission.
+    size_t getQueueSize() const;
+
+    /// @brief Returns the maximum number of NCRs allowed in the queue.
+    size_t getQueueMaxSize() const;
+
+    /// @brief Returns the nth NCR queued for transmission.
+    ///
+    /// Note that the entry is not removed from the queue.
+    /// @param index the index of the entry in the queue to fetch.
+    /// Valid values are 0 (front of the queue) to (queue size - 1).
+    /// @note This method is for test purposes only.
+    ///
+    /// @return Pointer reference to the queue entry.
+    ///
+    /// @throw D2ClientError if sender instance is null. Underlying layer
+    /// may throw NCRSenderExceptions exceptions.
+    const dhcp_ddns::NameChangeRequestPtr& peekAt(const size_t index) const;
+
+    /// @brief Removes all NCRs queued for transmission.
+    ///
+    /// @throw D2ClientError if sender instance is null. Underlying layer
+    /// may throw NCRSenderExceptions exceptions.
+    void clearQueue();
+
+    /// @brief Processes sender IO events
+    ///
+    /// Serves as callback registered for the sender's select-fd with IfaceMgr.
+    /// It instructs the sender to execute the next ready IO handler.
+    /// It provides an instance method that can be bound via std::bind, as
+    /// NameChangeSender is abstract.
+    void runReadyIO();
+
+    /// @brief Suspends sending requests.
+    ///
+    /// This method is intended to be used when IO errors occur.  It toggles
+    /// the enable-updates configuration flag to off, and takes the sender
+    /// out of send mode.  Messages in the sender's queue will remain in the
+    /// queue.
+    /// @todo This logic may change in NameChangeSender is altered allow
+    /// queuing while stopped.  Currently when a sender is not in send mode
+    /// it will not accept additional messages.
+    void suspendUpdates();
+
+protected:
+    /// @brief Function operator implementing the NCR sender callback.
+    ///
+    /// This method is invoked each time the NameChangeSender completes
+    /// an asynchronous send.
+    ///
+    /// @param result contains that send outcome status.
+    /// @param ncr is a pointer to the NameChangeRequest that was
+    /// delivered (or attempted).
+    ///
+    /// @throw This method MUST NOT throw.
+    virtual void operator ()(const dhcp_ddns::NameChangeSender::Result result,
+                             dhcp_ddns::NameChangeRequestPtr& ncr);
+
+    /// @brief Fetches the sender's select-fd.
+    ///
+    /// The select-fd may be used with select() or poll().  If the sender has
+    /// IO waiting to process, the fd will evaluate as !EWOULDBLOCK.
+    /// @note This is only exposed for testing purposes.
+    ///
+    /// @return The sender's select-fd
+    ///
+    /// @throw D2ClientError if the sender does not exist or is not in send
+    /// mode.
+    int getSelectFd();
+
+    /// @brief Fetches the select-fd that is currently registered.
+    ///
+    /// @return The currently registered select-fd or
+    /// util::WatchSocket::SOCKET_NOT_VALID.
+    ///
+    /// @note This is only exposed for testing purposes.
+    int getRegisteredSelectFd();
+
+private:
+    /// @brief Container class for DHCP-DDNS configuration parameters.
+    D2ClientConfigPtr d2_client_config_;
+
+    /// @brief Pointer to the current interface to DHCP-DDNS.
+    dhcp_ddns::NameChangeSenderPtr name_change_sender_;
+
+    /// @brief Private IOService to use if calling layer doesn't wish to
+    /// supply one.
+    boost::shared_ptr<asiolink::IOService> private_io_service_;
+
+    /// @brief Application supplied error handler invoked when a send
+    /// completes with a failed status.
+    D2ClientErrorHandler client_error_handler_;
+
+    /// @brief Remembers the select-fd registered with IfaceMgr.
+    int registered_select_fd_;
+};
+
+template <class T>
+void
+D2ClientMgr::adjustFqdnFlags(const T& fqdn, T& fqdn_resp, const DdnsParams& ddns_params) {
+    bool server_s = false;
+    bool server_n = false;
+    analyzeFqdn(fqdn.getFlag(T::FLAG_S), fqdn.getFlag(T::FLAG_N),
+                server_s, server_n, ddns_params);
+
+    // Reset the flags to zero to avoid triggering N and S both 1 check.
+    fqdn_resp.resetFlags();
+
+    // Set S and N flags.
+    fqdn_resp.setFlag(T::FLAG_S, server_s);
+    fqdn_resp.setFlag(T::FLAG_N, server_n);
+
+    // Set O flag true if server S overrides client S.
+    fqdn_resp.setFlag(T::FLAG_O, (fqdn.getFlag(T::FLAG_S) != server_s));
+}
+
+template <class T>
+void
+D2ClientMgr::getUpdateDirections(const T& fqdn_resp,
+                                 bool& forward, bool& reverse) {
+    forward = fqdn_resp.getFlag(T::FLAG_S);
+    reverse = !(fqdn_resp.getFlag(T::FLAG_N));
+}
+
+template <class T>
+void
+D2ClientMgr::adjustDomainName(const T& fqdn, T& fqdn_resp, const DdnsParams& ddns_params) {
+    // If we're configured to replace it or the supplied name is blank
+    // set the response name to blank.
+    D2ClientConfig::ReplaceClientNameMode mode = ddns_params.getReplaceClientNameMode();
+    if ((mode == D2ClientConfig::RCM_ALWAYS || mode == D2ClientConfig::RCM_WHEN_PRESENT) ||
+        fqdn.getDomainName().empty()) {
+        fqdn_resp.setDomainName("", T::PARTIAL);
+    } else {
+        // Sanitize the name the client sent us, if we're configured to do so.
+        std::string client_name = fqdn.getDomainName();
+
+        isc::util::str::StringSanitizerPtr sanitizer = ddns_params.getHostnameSanitizer();
+        if (sanitizer) {
+            // We need the raw text form, so we can replace escaped chars
+            dns::Name tmp(client_name);
+            std::string raw_name = tmp.toRawText();
+
+            // We do not know if the sanitizer's regexp preserves dots, so
+            // we'll scrub it label by label. Yeah, lucky us.
+            // Using boost::split is simpler than using dns::Name::split() as
+            // that returns Names which have trailing dots etc.
+            std::vector<std::string> labels;
+            boost::algorithm::split(labels, raw_name, boost::is_any_of("."));
+            std::stringstream ss;
+            for (auto label = labels.begin(); label != labels.end(); ++label ) {
+                if (label != labels.begin()) {
+                    ss << ".";
+                }
+
+                ss << sanitizer->scrub(*label);
+            }
+
+            client_name = ss.str();
+        }
+
+        // If the supplied name is partial, qualify it by adding the suffix.
+        if (fqdn.getDomainNameType() == T::PARTIAL) {
+            fqdn_resp.setDomainName(qualifyName(client_name, ddns_params, true), T::FULL);
+        } else  {
+            fqdn_resp.setDomainName(client_name, T::FULL);
+        }
+    }
+}
+
+
+/// @brief Defines a pointer for D2ClientMgr instances.
+typedef boost::shared_ptr<D2ClientMgr> D2ClientMgrPtr;
+
+
+} // namespace isc
+} // namespace dhcp
+
+#endif