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/*
*
* Copyright 2016 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#ifndef GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H
#define GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H
#include <grpc/support/port_platform.h>
#include "absl/container/inlined_vector.h"
#include <grpc/support/string_util.h>
#include <grpc/impl/codegen/grpc_types.h>
#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/gprpp/ref_counted.h"
#include "src/core/lib/gprpp/sync.h"
#include "src/core/lib/iomgr/closure.h"
#include "src/core/lib/iomgr/endpoint.h"
#include "src/core/lib/iomgr/exec_ctx.h"
#include "src/core/lib/iomgr/tcp_server.h"
#include "src/core/lib/iomgr/timer.h"
namespace grpc_core {
/// Handshakers are used to perform initial handshakes on a connection
/// before the client sends the initial request. Some examples of what
/// a handshaker can be used for includes support for HTTP CONNECT on
/// the client side and various types of security initialization.
///
/// In general, handshakers should be used via a handshake manager.
/// Arguments passed through handshakers and to the on_handshake_done callback.
///
/// For handshakers, all members are input/output parameters; for
/// example, a handshaker may read from or write to \a endpoint and
/// then later replace it with a wrapped endpoint. Similarly, a
/// handshaker may modify \a args.
///
/// A handshaker takes ownership of the members while a handshake is in
/// progress. Upon failure or shutdown of an in-progress handshaker,
/// the handshaker is responsible for destroying the members and setting
/// them to NULL before invoking the on_handshake_done callback.
///
/// For the on_handshake_done callback, all members are input arguments,
/// which the callback takes ownership of.
struct HandshakerArgs {
grpc_endpoint* endpoint = nullptr;
grpc_channel_args* args = nullptr;
grpc_slice_buffer* read_buffer = nullptr;
// A handshaker may set this to true before invoking on_handshake_done
// to indicate that subsequent handshakers should be skipped.
bool exit_early = false;
// User data passed through the handshake manager. Not used by
// individual handshakers.
void* user_data = nullptr;
};
///
/// Handshaker
///
class Handshaker : public RefCounted<Handshaker> {
public:
~Handshaker() override = default;
virtual void Shutdown(grpc_error* why) = 0;
virtual void DoHandshake(grpc_tcp_server_acceptor* acceptor,
grpc_closure* on_handshake_done,
HandshakerArgs* args) = 0;
virtual const char* name() const = 0;
};
//
// HandshakeManager
//
class HandshakeManager : public RefCounted<HandshakeManager> {
public:
HandshakeManager();
~HandshakeManager() override;
/// Add \a mgr to the server side list of all pending handshake managers, the
/// list starts with \a *head.
// Not thread-safe. Caller needs to synchronize.
void AddToPendingMgrList(HandshakeManager** head);
/// Remove \a mgr from the server side list of all pending handshake managers.
// Not thread-safe. Caller needs to synchronize.
void RemoveFromPendingMgrList(HandshakeManager** head);
/// Shutdown all pending handshake managers starting at head on the server
/// side. Not thread-safe. Caller needs to synchronize.
void ShutdownAllPending(grpc_error* why);
/// Adds a handshaker to the handshake manager.
/// Takes ownership of \a handshaker.
void Add(RefCountedPtr<Handshaker> handshaker);
/// Shuts down the handshake manager (e.g., to clean up when the operation is
/// aborted in the middle).
void Shutdown(grpc_error* why);
/// Invokes handshakers in the order they were added.
/// Takes ownership of \a endpoint, and then passes that ownership to
/// the \a on_handshake_done callback.
/// Does NOT take ownership of \a channel_args. Instead, makes a copy before
/// invoking the first handshaker.
/// \a acceptor will be nullptr for client-side handshakers.
///
/// When done, invokes \a on_handshake_done with a HandshakerArgs
/// object as its argument. If the callback is invoked with error !=
/// GRPC_ERROR_NONE, then handshaking failed and the handshaker has done
/// the necessary clean-up. Otherwise, the callback takes ownership of
/// the arguments.
void DoHandshake(grpc_endpoint* endpoint,
const grpc_channel_args* channel_args, grpc_millis deadline,
grpc_tcp_server_acceptor* acceptor,
grpc_iomgr_cb_func on_handshake_done, void* user_data);
private:
bool CallNextHandshakerLocked(grpc_error* error);
// A function used as the handshaker-done callback when chaining
// handshakers together.
static void CallNextHandshakerFn(void* arg, grpc_error* error);
// Callback invoked when deadline is exceeded.
static void OnTimeoutFn(void* arg, grpc_error* error);
static const size_t HANDSHAKERS_INIT_SIZE = 2;
gpr_mu mu_;
bool is_shutdown_ = false;
// An array of handshakers added via grpc_handshake_manager_add().
absl::InlinedVector<RefCountedPtr<Handshaker>, HANDSHAKERS_INIT_SIZE>
handshakers_;
// The index of the handshaker to invoke next and closure to invoke it.
size_t index_ = 0;
grpc_closure call_next_handshaker_;
// The acceptor to call the handshakers with.
grpc_tcp_server_acceptor* acceptor_;
// Deadline timer across all handshakers.
grpc_timer deadline_timer_;
grpc_closure on_timeout_;
// The final callback and user_data to invoke after the last handshaker.
grpc_closure on_handshake_done_;
// Handshaker args.
HandshakerArgs args_;
// Links to the previous and next managers in a list of all pending handshakes
// Used at server side only.
HandshakeManager* prev_ = nullptr;
HandshakeManager* next_ = nullptr;
};
} // namespace grpc_core
// TODO(arjunroy): These are transitional to account for the new handshaker API
// and will eventually be removed entirely.
typedef grpc_core::HandshakeManager grpc_handshake_manager;
typedef grpc_core::Handshaker grpc_handshaker;
void grpc_handshake_manager_add(grpc_handshake_manager* mgr,
grpc_handshaker* handshaker);
#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H */
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