--- /dev/null
+// -*- 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_DISPATCHER_H
+#define CEPH_DISPATCHER_H
+
+#include "include/assert.h"
+#include "include/buffer_fwd.h"
+#include "include/assert.h"
+
+class Messenger;
+class Message;
+class Connection;
+class AuthAuthorizer;
+class CryptoKey;
+class CephContext;
+
+class Dispatcher {
+public:
+ explicit Dispatcher(CephContext *cct_)
+ : cct(cct_)
+ {
+ }
+ virtual ~Dispatcher() { }
+
+ /**
+ * The Messenger calls this function to query if you are capable
+ * of "fast dispatch"ing a message. Indicating that you can fast
+ * dispatch it requires that you:
+ * 1) Handle the Message quickly and without taking long-term contended
+ * locks. (This function is likely to be called in-line with message
+ * receipt.)
+ * 2) Be able to accept the Message even if you have not yet received
+ * an ms_handle_accept() notification for the Connection it is associated
+ * with, and even if you *have* called mark_down() or received an
+ * ms_handle_reset() (or similar) call on the Connection. You will
+ * not receive more than one dead "message" (and should generally be
+ * prepared for that circumstance anyway, since the normal dispatch can begin,
+ * then trigger Connection failure before it's percolated through your system).
+ * We provide ms_handle_fast_[connect|accept] calls if you need them, under
+ * similar speed and state constraints as fast_dispatch itself.
+ * 3) Be able to make a determination on fast_dispatch without relying
+ * on particular system state -- the ms_can_fast_dispatch() call might
+ * be called multiple times on a single message; the state might change between
+ * calling ms_can_fast_dispatch and ms_fast_dispatch; etc.
+ *
+ * @param m The message we want to fast dispatch.
+ * @returns True if the message can be fast dispatched; false otherwise.
+ */
+ virtual bool ms_can_fast_dispatch(const Message *m) const { return false;}
+ /**
+ * This function determines if a dispatcher is included in the
+ * list of fast-dispatch capable Dispatchers.
+ * @returns True if the Dispatcher can handle any messages via
+ * fast dispatch; false otherwise.
+ */
+ virtual bool ms_can_fast_dispatch_any() const { return false; }
+ /**
+ * Perform a "fast dispatch" on a given message. See
+ * ms_can_fast_dispatch() for the requirements.
+ *
+ * @param m The Message to fast dispatch.
+ */
+ virtual void ms_fast_dispatch(Message *m) { ceph_abort(); }
+ /**
+ * Let the Dispatcher preview a Message before it is dispatched. This
+ * function is called on *every* Message, prior to the fast/regular dispatch
+ * decision point, but it is only used on fast-dispatch capable systems. An
+ * implementation of ms_fast_preprocess must be essentially lock-free in the
+ * same way as the ms_fast_dispatch function is (in particular, ms_fast_preprocess
+ * may be called while the Messenger holds internal locks that prevent progress from
+ * other threads, so any locks it takes must be at the very bottom of the hierarchy).
+ * Messages are delivered in receipt order within a single Connection, but there are
+ * no guarantees across Connections. This makes it useful for some limited
+ * coordination between Messages which can be fast_dispatch'ed and those which must
+ * go through normal dispatch.
+ *
+ * @param m A message which has been received
+ */
+ virtual void ms_fast_preprocess(Message *m) {}
+ /**
+ * The Messenger calls this function to deliver a single message.
+ *
+ * @param m The message being delivered. You (the Dispatcher)
+ * are given a single reference count on it.
+ */
+ virtual bool ms_dispatch(Message *m) = 0;
+
+ /**
+ * This function will be called whenever a Connection is newly-created
+ * or reconnects in the Messenger.
+ *
+ * @param con The new Connection which has been established. You are not
+ * granted a reference to it -- take one if you need one!
+ */
+ virtual void ms_handle_connect(Connection *con) {}
+
+ /**
+ * This function will be called synchronously whenever a Connection is
+ * newly-created or reconnects in the Messenger, if you support fast
+ * dispatch. It is guaranteed to be called before any messages are
+ * dispatched.
+ *
+ * @param con The new Connection which has been established. You are not
+ * granted a reference to it -- take one if you need one!
+ */
+ virtual void ms_handle_fast_connect(Connection *con) {}
+
+ /**
+ * Callback indicating we have accepted an incoming connection.
+ *
+ * @param con The (new or existing) Connection associated with the session
+ */
+ virtual void ms_handle_accept(Connection *con) {}
+
+ /**
+ * Callback indicating we have accepted an incoming connection, if you
+ * support fast dispatch. It is guaranteed to be called before any messages
+ * are dispatched.
+ *
+ * @param con The (new or existing) Connection associated with the session
+ */
+ virtual void ms_handle_fast_accept(Connection *con) {}
+
+ /*
+ * this indicates that the ordered+reliable delivery semantics have
+ * been violated. Messages may have been lost due to a fault
+ * in the network connection.
+ * Only called on lossy Connections.
+ *
+ * @param con The Connection which broke. You are not granted
+ * a reference to it.
+ */
+ virtual bool ms_handle_reset(Connection *con) = 0;
+
+ /**
+ * This indicates that the ordered+reliable delivery semantics
+ * have been violated because the remote somehow reset.
+ * It implies that incoming messages were dropped, and
+ * probably some of our previous outgoing messages were too.
+ *
+ * @param con The Connection which broke. You are not granted
+ * a reference to it.
+ */
+ virtual void ms_handle_remote_reset(Connection *con) = 0;
+
+ /**
+ * This indicates that the connection is both broken and further
+ * connection attempts are failing because other side refuses
+ * it.
+ *
+ * @param con The Connection which broke. You are not granted
+ * a reference to it.
+ */
+ virtual bool ms_handle_refused(Connection *con) = 0;
+
+ /**
+ * @defgroup Authentication
+ * @{
+ */
+ /**
+ * Retrieve the AuthAuthorizer for the given peer type. It might not
+ * provide one if it knows there is no AuthAuthorizer for that type.
+ *
+ * @param dest_type The peer type we want the authorizer for.
+ * @param a Double pointer to an AuthAuthorizer. The Dispatcher will fill
+ * in *a with the correct AuthAuthorizer, if it can. Make sure that you have
+ * set *a to NULL before calling in.
+ * @param force_new Force the Dispatcher to wait for a new set of keys before
+ * returning the authorizer.
+ *
+ * @return True if this function call properly filled in *a, false otherwise.
+ */
+ virtual bool ms_get_authorizer(int dest_type, AuthAuthorizer **a, bool force_new) { return false; }
+ /**
+ * Verify the authorizer for a new incoming Connection.
+ *
+ * @param con The new incoming Connection
+ * @param peer_type The type of the endpoint which initiated this Connection
+ * @param protocol The ID of the protocol in use (at time of writing, cephx or none)
+ * @param authorizer The authorization string supplied by the remote
+ * @param authorizer_reply Output param: The string we should send back to
+ * the remote to authorize ourselves. Only filled in if isvalid
+ * @param isvalid Output param: True if authorizer is valid, false otherwise
+ *
+ * @return True if we were able to prove or disprove correctness of
+ * authorizer, false otherwise.
+ */
+ virtual bool ms_verify_authorizer(Connection *con,
+ int peer_type,
+ int protocol,
+ ceph::bufferlist& authorizer,
+ ceph::bufferlist& authorizer_reply,
+ bool& isvalid,
+ CryptoKey& session_key) { return false; }
+ /**
+ * @} //Authentication
+ */
+protected:
+ CephContext *cct;
+private:
+ explicit Dispatcher(const Dispatcher &rhs);
+ Dispatcher& operator=(const Dispatcher &rhs);
+};
+
+#endif
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