Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

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

1 files changed, 774 insertions, 0 deletions

diff --git a/src/mon/MonClient.h b/src/mon/MonClient.h
new file mode 100644
index 000000000..6a7daa814
--- /dev/null
+++ b/src/mon/MonClient.h
@@ -0,0 +1,774 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software 
+ * Foundation.  See file COPYING.
+ * 
+ */
+#ifndef CEPH_MONCLIENT_H
+#define CEPH_MONCLIENT_H
+
+#include <functional>
+#include <list>
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "msg/Messenger.h"
+
+#include "MonMap.h"
+#include "MonSub.h"
+
+#include "common/async/completion.h"
+#include "common/Timer.h"
+#include "common/config.h"
+#include "messages/MMonGetVersion.h"
+
+#include "auth/AuthClient.h"
+#include "auth/AuthServer.h"
+
+class MMonMap;
+class MConfig;
+class MMonGetVersionReply;
+class MMonCommandAck;
+class LogClient;
+class AuthClientHandler;
+class AuthRegistry;
+class KeyRing;
+class RotatingKeyRing;
+
+class MonConnection {
+public:
+  MonConnection(CephContext *cct,
+		ConnectionRef conn,
+		uint64_t global_id,
+		AuthRegistry *auth_registry);
+  ~MonConnection();
+  MonConnection(MonConnection&& rhs) = default;
+  MonConnection& operator=(MonConnection&&) = default;
+  MonConnection(const MonConnection& rhs) = delete;
+  MonConnection& operator=(const MonConnection&) = delete;
+  int handle_auth(MAuthReply *m,
+		  const EntityName& entity_name,
+		  uint32_t want_keys,
+		  RotatingKeyRing* keyring);
+  int authenticate(MAuthReply *m);
+  void start(epoch_t epoch,
+             const EntityName& entity_name);
+  bool have_session() const;
+  uint64_t get_global_id() const {
+    return global_id;
+  }
+  ConnectionRef get_con() {
+    return con;
+  }
+  std::unique_ptr<AuthClientHandler>& get_auth() {
+    return auth;
+  }
+
+  int get_auth_request(
+    uint32_t *method,
+    std::vector<uint32_t> *preferred_modes,
+    ceph::buffer::list *out,
+    const EntityName& entity_name,
+    uint32_t want_keys,
+    RotatingKeyRing* keyring);
+  int handle_auth_reply_more(
+    AuthConnectionMeta *auth_meta,
+    const ceph::buffer::list& bl,
+    ceph::buffer::list *reply);
+  int handle_auth_done(
+    AuthConnectionMeta *auth_meta,
+    uint64_t global_id,
+    const ceph::buffer::list& bl,
+    CryptoKey *session_key,
+    std::string *connection_secret);
+  int handle_auth_bad_method(
+    uint32_t old_auth_method,
+    int result,
+    const std::vector<uint32_t>& allowed_methods,
+    const std::vector<uint32_t>& allowed_modes);
+
+  bool is_con(Connection *c) const {
+    return con.get() == c;
+  }
+  void queue_command(Message *m) {
+    pending_tell_command = m;
+  }
+
+private:
+  int _negotiate(MAuthReply *m,
+		 const EntityName& entity_name,
+		 uint32_t want_keys,
+		 RotatingKeyRing* keyring);
+  int _init_auth(uint32_t method,
+		 const EntityName& entity_name,
+		 uint32_t want_keys,
+		 RotatingKeyRing* keyring,
+		 bool msgr2);
+
+private:
+  CephContext *cct;
+  enum class State {
+    NONE,
+    NEGOTIATING,       // v1 only
+    AUTHENTICATING,    // v1 and v2
+    HAVE_SESSION,
+  };
+  State state = State::NONE;
+  ConnectionRef con;
+  int auth_method = -1;
+  utime_t auth_start;
+
+  std::unique_ptr<AuthClientHandler> auth;
+  uint64_t global_id;
+
+  MessageRef pending_tell_command;
+
+  AuthRegistry *auth_registry;
+};
+
+
+struct MonClientPinger : public Dispatcher,
+			 public AuthClient {
+  ceph::mutex lock = ceph::make_mutex("MonClientPinger::lock");
+  ceph::condition_variable ping_recvd_cond;
+  std::string *result;
+  bool done;
+  RotatingKeyRing *keyring;
+  std::unique_ptr<MonConnection> mc;
+
+  MonClientPinger(CephContext *cct_,
+		  RotatingKeyRing *keyring,
+		  std::string *res_) :
+    Dispatcher(cct_),
+    result(res_),
+    done(false),
+    keyring(keyring)
+  { }
+
+  int wait_for_reply(double timeout = 0.0) {
+    std::unique_lock locker{lock};
+    if (timeout <= 0) {
+      timeout = std::chrono::duration<double>(cct->_conf.get_val<std::chrono::seconds>("client_mount_timeout")).count();
+    }
+    done = false;
+    if (ping_recvd_cond.wait_for(locker,
+				 ceph::make_timespan(timeout),
+				 [this] { return done; })) {
+      return 0;
+    } else {
+      return ETIMEDOUT;
+    }
+  }
+
+  bool ms_dispatch(Message *m) override {
+    using ceph::decode;
+    std::lock_guard l(lock);
+    if (m->get_type() != CEPH_MSG_PING)
+      return false;
+
+    ceph::buffer::list &payload = m->get_payload();
+    if (result && payload.length() > 0) {
+      auto p = std::cbegin(payload);
+      decode(*result, p);
+    }
+    done = true;
+    ping_recvd_cond.notify_all();
+    m->put();
+    return true;
+  }
+  bool ms_handle_reset(Connection *con) override {
+    std::lock_guard l(lock);
+    done = true;
+    ping_recvd_cond.notify_all();
+    return true;
+  }
+  void ms_handle_remote_reset(Connection *con) override {}
+  bool ms_handle_refused(Connection *con) override {
+    return false;
+  }
+
+  // AuthClient
+  int get_auth_request(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    uint32_t *auth_method,
+    std::vector<uint32_t> *preferred_modes,
+    ceph::buffer::list *bl) override {
+    return mc->get_auth_request(auth_method, preferred_modes, bl,
+				cct->_conf->name, 0, keyring);
+  }
+  int handle_auth_reply_more(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    const ceph::buffer::list& bl,
+    ceph::buffer::list *reply) override {
+    return mc->handle_auth_reply_more(auth_meta, bl, reply);
+  }
+  int handle_auth_done(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    uint64_t global_id,
+    uint32_t con_mode,
+    const ceph::buffer::list& bl,
+    CryptoKey *session_key,
+    std::string *connection_secret) override {
+    return mc->handle_auth_done(auth_meta, global_id, bl,
+				session_key, connection_secret);
+  }
+  int handle_auth_bad_method(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    uint32_t old_auth_method,
+    int result,
+    const std::vector<uint32_t>& allowed_methods,
+    const std::vector<uint32_t>& allowed_modes) override {
+    return mc->handle_auth_bad_method(old_auth_method, result,
+				      allowed_methods, allowed_modes);
+  }
+};
+
+const boost::system::error_category& monc_category() noexcept;
+
+enum class monc_errc {
+  shutting_down = 1, // Command failed due to MonClient shutting down
+  session_reset, // Monitor session was reset
+  rank_dne, // Requested monitor rank does not exist
+  mon_dne, // Requested monitor does not exist
+  timed_out, // Monitor operation timed out
+  mon_unavailable // Monitor unavailable
+};
+
+namespace boost::system {
+template<>
+struct is_error_code_enum<::monc_errc> {
+  static const bool value = true;
+};
+}
+
+//  implicit conversion:
+inline boost::system::error_code make_error_code(monc_errc e) noexcept {
+  return { static_cast<int>(e), monc_category() };
+}
+
+// explicit conversion:
+inline boost::system::error_condition make_error_condition(monc_errc e) noexcept {
+  return { static_cast<int>(e), monc_category() };
+}
+
+const boost::system::error_category& monc_category() noexcept;
+
+class MonClient : public Dispatcher,
+		  public AuthClient,
+		  public AuthServer /* for mgr, osd, mds */ {
+  static constexpr auto dout_subsys = ceph_subsys_monc;
+public:
+  // Error, Newest, Oldest
+  using VersionSig = void(boost::system::error_code, version_t, version_t);
+  using VersionCompletion = ceph::async::Completion<VersionSig>;
+
+  using CommandSig = void(boost::system::error_code, std::string,
+			  ceph::buffer::list);
+  using CommandCompletion = ceph::async::Completion<CommandSig>;
+
+  MonMap monmap;
+  std::map<std::string,std::string> config_mgr;
+
+private:
+  Messenger *messenger;
+
+  std::unique_ptr<MonConnection> active_con;
+  std::map<entity_addrvec_t, MonConnection> pending_cons;
+  std::set<unsigned> tried;
+
+  EntityName entity_name;
+
+  mutable ceph::mutex monc_lock = ceph::make_mutex("MonClient::monc_lock");
+  SafeTimer timer;
+  boost::asio::io_context& service;
+  boost::asio::io_context::strand finish_strand{service};
+
+  bool initialized;
+  bool stopping = false;
+
+  LogClient *log_client;
+  bool more_log_pending;
+
+  void send_log(bool flush = false);
+
+  bool ms_dispatch(Message *m) override;
+  bool ms_handle_reset(Connection *con) override;
+  void ms_handle_remote_reset(Connection *con) override {}
+  bool ms_handle_refused(Connection *con) override { return false; }
+
+  void handle_monmap(MMonMap *m);
+  void handle_config(MConfig *m);
+
+  void handle_auth(MAuthReply *m);
+
+  // monitor session
+  utime_t last_keepalive;
+  utime_t last_send_log;
+
+  void tick();
+  void schedule_tick();
+
+  // monclient
+  bool want_monmap;
+  ceph::condition_variable map_cond;
+  bool passthrough_monmap = false;
+
+  bool want_bootstrap_config = false;
+  ceph::ref_t<MConfig> bootstrap_config;
+
+  // authenticate
+  std::unique_ptr<AuthClientHandler> auth;
+  uint32_t want_keys = 0;
+  uint64_t global_id = 0;
+  ceph::condition_variable auth_cond;
+  int authenticate_err = 0;
+  bool authenticated = false;
+
+  std::list<MessageRef> waiting_for_session;
+  utime_t last_rotating_renew_sent;
+  bool had_a_connection;
+  double reopen_interval_multiplier;
+
+  Dispatcher *handle_authentication_dispatcher = nullptr;
+  bool _opened() const;
+  bool _hunting() const;
+  void _start_hunting();
+  void _finish_hunting(int auth_err);
+  void _finish_auth(int auth_err);
+  void _reopen_session(int rank = -1);
+  void _add_conn(unsigned rank);
+  void _add_conns();
+  void _un_backoff();
+  void _send_mon_message(MessageRef m);
+
+  std::map<entity_addrvec_t, MonConnection>::iterator _find_pending_con(
+    const ConnectionRef& con) {
+    for (auto i = pending_cons.begin(); i != pending_cons.end(); ++i) {
+      if (i->second.get_con() == con) {
+	return i;
+      }
+    }
+    return pending_cons.end();
+  }
+
+public:
+  // AuthClient
+  int get_auth_request(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    uint32_t *method,
+    std::vector<uint32_t> *preferred_modes,
+    ceph::buffer::list *bl) override;
+  int handle_auth_reply_more(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    const ceph::buffer::list& bl,
+    ceph::buffer::list *reply) override;
+  int handle_auth_done(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    uint64_t global_id,
+    uint32_t con_mode,
+    const ceph::buffer::list& bl,
+    CryptoKey *session_key,
+    std::string *connection_secret) override;
+  int handle_auth_bad_method(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    uint32_t old_auth_method,
+    int result,
+    const std::vector<uint32_t>& allowed_methods,
+    const std::vector<uint32_t>& allowed_modes) override;
+  // AuthServer
+  int handle_auth_request(
+    Connection *con,
+    AuthConnectionMeta *auth_meta,
+    bool more,
+    uint32_t auth_method,
+    const ceph::buffer::list& bl,
+    ceph::buffer::list *reply) override;
+
+  void set_entity_name(EntityName name) { entity_name = name; }
+  void set_handle_authentication_dispatcher(Dispatcher *d) {
+    handle_authentication_dispatcher = d;
+  }
+  int _check_auth_tickets();
+  int _check_auth_rotating();
+  int wait_auth_rotating(double timeout);
+
+  int authenticate(double timeout=0.0);
+  bool is_authenticated() const {return authenticated;}
+
+  bool is_connected() const { return active_con != nullptr; }
+
+  /**
+   * Try to flush as many log messages as we can in a single
+   * message.  Use this before shutting down to transmit your
+   * last message.
+   */
+  void flush_log();
+
+private:
+  // mon subscriptions
+  MonSub sub;
+  void _renew_subs();
+  void handle_subscribe_ack(MMonSubscribeAck* m);
+
+public:
+  void renew_subs() {
+    std::lock_guard l(monc_lock);
+    _renew_subs();
+  }
+  bool sub_want(std::string what, version_t start, unsigned flags) {
+    std::lock_guard l(monc_lock);
+    return sub.want(what, start, flags);
+  }
+  void sub_got(std::string what, version_t have) {
+    std::lock_guard l(monc_lock);
+    sub.got(what, have);
+  }
+  void sub_unwant(std::string what) {
+    std::lock_guard l(monc_lock);
+    sub.unwant(what);
+  }
+  bool sub_want_increment(std::string what, version_t start, unsigned flags) {
+    std::lock_guard l(monc_lock);
+    return sub.inc_want(what, start, flags);
+  }
+
+  std::unique_ptr<KeyRing> keyring;
+  std::unique_ptr<RotatingKeyRing> rotating_secrets;
+
+ public:
+  MonClient(CephContext *cct_, boost::asio::io_context& service);
+  MonClient(const MonClient &) = delete;
+  MonClient& operator=(const MonClient &) = delete;
+  ~MonClient() override;
+
+  int init();
+  void shutdown();
+
+  void set_log_client(LogClient *clog) {
+    log_client = clog;
+  }
+  LogClient *get_log_client() {
+    return log_client;
+  }
+
+  int build_initial_monmap();
+  int get_monmap();
+  int get_monmap_and_config();
+  /**
+   * If you want to see MonMap messages, set this and
+   * the MonClient will tell the Messenger it hasn't
+   * dealt with it.
+   * Note that if you do this, *you* are of course responsible for
+   * putting the message reference!
+   */
+  void set_passthrough_monmap() {
+    std::lock_guard l(monc_lock);
+    passthrough_monmap = true;
+  }
+  void unset_passthrough_monmap() {
+    std::lock_guard l(monc_lock);
+    passthrough_monmap = false;
+  }
+  /**
+   * Ping monitor with ID @p mon_id and record the resulting
+   * reply in @p result_reply.
+   *
+   * @param[in]  mon_id Target monitor's ID
+   * @param[out] result_reply reply from mon.ID, if param != NULL
+   * @returns    0 in case of success; < 0 in case of error,
+   *             -ETIMEDOUT if monitor didn't reply before timeout
+   *             expired (default: conf->client_mount_timeout).
+   */
+  int ping_monitor(const std::string &mon_id, std::string *result_reply);
+
+  void send_mon_message(Message *m) {
+    send_mon_message(MessageRef{m, false});
+  }
+  void send_mon_message(MessageRef m);
+
+  void reopen_session() {
+    std::lock_guard l(monc_lock);
+    _reopen_session();
+  }
+
+  const uuid_d& get_fsid() const {
+    return monmap.fsid;
+  }
+
+  entity_addrvec_t get_mon_addrs(unsigned i) const {
+    std::lock_guard l(monc_lock);
+    if (i < monmap.size())
+      return monmap.get_addrs(i);
+    return entity_addrvec_t();
+  }
+  int get_num_mon() const {
+    std::lock_guard l(monc_lock);
+    return monmap.size();
+  }
+
+  uint64_t get_global_id() const {
+    std::lock_guard l(monc_lock);
+    return global_id;
+  }
+
+  void set_messenger(Messenger *m) { messenger = m; }
+  entity_addrvec_t get_myaddrs() const { return messenger->get_myaddrs(); }
+  AuthAuthorizer* build_authorizer(int service_id) const;
+
+  void set_want_keys(uint32_t want) {
+    want_keys = want;
+  }
+
+  // admin commands
+private:
+  uint64_t last_mon_command_tid;
+
+  struct MonCommand {
+    // for tell only
+    std::string target_name;
+    int target_rank = -1;
+    ConnectionRef target_con;
+    std::unique_ptr<MonConnection> target_session;
+    unsigned send_attempts = 0;  ///< attempt count for legacy mons
+    utime_t last_send_attempt;
+    uint64_t tid;
+    std::vector<std::string> cmd;
+    ceph::buffer::list inbl;
+    std::unique_ptr<CommandCompletion> onfinish;
+    std::optional<boost::asio::steady_timer> cancel_timer;
+
+    MonCommand(MonClient& monc, uint64_t t, std::unique_ptr<CommandCompletion> onfinish)
+      : tid(t), onfinish(std::move(onfinish)) {
+      auto timeout =
+          monc.cct->_conf.get_val<std::chrono::seconds>("rados_mon_op_timeout");
+      if (timeout.count() > 0) {
+	cancel_timer.emplace(monc.service, timeout);
+	cancel_timer->async_wait(
+          [this, &monc](boost::system::error_code ec) {
+	    if (ec)
+	      return;
+	    std::scoped_lock l(monc.monc_lock);
+	    monc._cancel_mon_command(tid);
+	  });
+      }
+    }
+
+    bool is_tell() const {
+      return target_name.size() || target_rank >= 0;
+    }
+  };
+  friend MonCommand;
+  std::map<uint64_t,MonCommand*> mon_commands;
+
+  void _send_command(MonCommand *r);
+  void _check_tell_commands();
+  void _resend_mon_commands();
+  int _cancel_mon_command(uint64_t tid);
+  void _finish_command(MonCommand *r, boost::system::error_code ret, std::string_view rs,
+		       bufferlist&& bl);
+  void _finish_auth();
+  void handle_mon_command_ack(MMonCommandAck *ack);
+  void handle_command_reply(MCommandReply *reply);
+
+public:
+  template<typename CompletionToken>
+  auto start_mon_command(const std::vector<std::string>& cmd,
+                         const ceph::buffer::list& inbl,
+			 CompletionToken&& token) {
+    ldout(cct,10) << __func__ << " cmd=" << cmd << dendl;
+    boost::asio::async_completion<CompletionToken, CommandSig> init(token);
+    {
+      std::scoped_lock l(monc_lock);
+      auto h = CommandCompletion::create(service.get_executor(),
+					 std::move(init.completion_handler));
+      if (!initialized || stopping) {
+	ceph::async::post(std::move(h), monc_errc::shutting_down, std::string{},
+			  bufferlist{});
+      } else {
+	auto r = new MonCommand(*this, ++last_mon_command_tid, std::move(h));
+	r->cmd = cmd;
+	r->inbl = inbl;
+	mon_commands.emplace(r->tid, r);
+	_send_command(r);
+      }
+    }
+    return init.result.get();
+  }
+
+  template<typename CompletionToken>
+  auto start_mon_command(int mon_rank, const std::vector<std::string>& cmd,
+			 const ceph::buffer::list& inbl, CompletionToken&& token) {
+    ldout(cct,10) << __func__ << " cmd=" << cmd << dendl;
+    boost::asio::async_completion<CompletionToken, CommandSig> init(token);
+    {
+      std::scoped_lock l(monc_lock);
+      auto h = CommandCompletion::create(service.get_executor(),
+					 std::move(init.completion_handler));
+      if (!initialized || stopping) {
+	ceph::async::post(std::move(h), monc_errc::shutting_down, std::string{},
+			  bufferlist{});
+      } else {
+	auto r = new MonCommand(*this, ++last_mon_command_tid, std::move(h));
+	r->target_rank = mon_rank;
+	r->cmd = cmd;
+	r->inbl = inbl;
+	mon_commands.emplace(r->tid, r);
+	_send_command(r);
+      }
+    }
+    return init.result.get();
+  }
+
+  template<typename CompletionToken>
+  auto start_mon_command(const std::string& mon_name,
+                         const std::vector<std::string>& cmd,
+			 const ceph::buffer::list& inbl,
+			 CompletionToken&& token) {
+    ldout(cct,10) << __func__ << " cmd=" << cmd << dendl;
+    boost::asio::async_completion<CompletionToken, CommandSig> init(token);
+    {
+      std::scoped_lock l(monc_lock);
+      auto h = CommandCompletion::create(service.get_executor(),
+					 std::move(init.completion_handler));
+      if (!initialized || stopping) {
+	ceph::async::post(std::move(h), monc_errc::shutting_down, std::string{},
+			  bufferlist{});
+      } else {
+	auto r = new MonCommand(*this, ++last_mon_command_tid, std::move(h));
+	// detect/tolerate mon *rank* passed as a string
+	std::string err;
+	int rank = strict_strtoll(mon_name.c_str(), 10, &err);
+	if (err.size() == 0 && rank >= 0) {
+	  ldout(cct,10) << __func__ << " interpreting name '" << mon_name
+			<< "' as rank " << rank << dendl;
+	  r->target_rank = rank;
+	} else {
+	  r->target_name = mon_name;
+	}
+	r->cmd = cmd;
+	r->inbl = inbl;
+	mon_commands.emplace(r->tid, r);
+	_send_command(r);
+      }
+    }
+    return init.result.get();
+  }
+
+  class ContextVerter {
+    std::string* outs;
+    ceph::bufferlist* outbl;
+    Context* onfinish;
+
+  public:
+    ContextVerter(std::string* outs, ceph::bufferlist* outbl, Context* onfinish)
+      : outs(outs), outbl(outbl), onfinish(onfinish) {}
+    ~ContextVerter() = default;
+    ContextVerter(const ContextVerter&) = default;
+    ContextVerter& operator =(const ContextVerter&) = default;
+    ContextVerter(ContextVerter&&) = default;
+    ContextVerter& operator =(ContextVerter&&) = default;
+
+    void operator()(boost::system::error_code e,
+		    std::string s,
+		    ceph::bufferlist bl) {
+      if (outs)
+	*outs = std::move(s);
+      if (outbl)
+	*outbl = std::move(bl);
+      if (onfinish)
+	onfinish->complete(ceph::from_error_code(e));
+    }
+  };
+
+  void start_mon_command(const vector<string>& cmd, const bufferlist& inbl,
+			 bufferlist *outbl, string *outs,
+			 Context *onfinish) {
+    start_mon_command(cmd, inbl, ContextVerter(outs, outbl, onfinish));
+  }
+  void start_mon_command(int mon_rank,
+			 const vector<string>& cmd, const bufferlist& inbl,
+			 bufferlist *outbl, string *outs,
+			 Context *onfinish) {
+    start_mon_command(mon_rank, cmd, inbl, ContextVerter(outs, outbl, onfinish));
+  }
+  void start_mon_command(const string &mon_name,  ///< mon name, with mon. prefix
+			 const vector<string>& cmd, const bufferlist& inbl,
+			 bufferlist *outbl, string *outs,
+			 Context *onfinish) {
+    start_mon_command(mon_name, cmd, inbl, ContextVerter(outs, outbl, onfinish));
+  }
+
+
+  // version requests
+public:
+  /**
+   * get latest known version(s) of cluster map
+   *
+   * @param map string name of map (e.g., 'osdmap')
+   * @param token context that will be triggered on completion
+   * @return (via Completion) {} on success,
+   *         boost::system::errc::resource_unavailable_try_again if we need to
+   *         resubmit our request
+   */
+  template<typename CompletionToken>
+  auto get_version(std::string&& map, CompletionToken&& token) {
+    boost::asio::async_completion<CompletionToken, VersionSig> init(token);
+    {
+      std::scoped_lock l(monc_lock);
+      auto m = ceph::make_message<MMonGetVersion>();
+      m->what = std::move(map);
+      m->handle = ++version_req_id;
+      version_requests.emplace(m->handle,
+			       VersionCompletion::create(
+				 service.get_executor(),
+				 std::move(init.completion_handler)));
+      _send_mon_message(m);
+    }
+    return init.result.get();
+  }
+
+  /**
+   * Run a callback within our lock, with a reference
+   * to the MonMap
+   */
+  template<typename Callback, typename...Args>
+  auto with_monmap(Callback&& cb, Args&&...args) const ->
+    decltype(cb(monmap, std::forward<Args>(args)...)) {
+    std::lock_guard l(monc_lock);
+    return std::forward<Callback>(cb)(monmap, std::forward<Args>(args)...);
+  }
+
+  void register_config_callback(md_config_t::config_callback fn);
+  void register_config_notify_callback(std::function<void(void)> f) {
+    config_notify_cb = f;
+  }
+  md_config_t::config_callback get_config_callback();
+
+private:
+
+  std::map<ceph_tid_t, std::unique_ptr<VersionCompletion>> version_requests;
+  ceph_tid_t version_req_id;
+  void handle_get_version_reply(MMonGetVersionReply* m);
+  md_config_t::config_callback config_cb;
+  std::function<void(void)> config_notify_cb;
+};
+
+#endif