3 * Copyright 2016 gRPC authors.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
19 #ifndef GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H
20 #define GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H
22 #include <grpc/support/port_platform.h>
24 #include "absl/container/inlined_vector.h"
26 #include <grpc/support/string_util.h>
28 #include <grpc/impl/codegen/grpc_types.h>
30 #include "src/core/lib/channel/channel_args.h"
31 #include "src/core/lib/gprpp/ref_counted.h"
32 #include "src/core/lib/gprpp/sync.h"
33 #include "src/core/lib/iomgr/closure.h"
34 #include "src/core/lib/iomgr/endpoint.h"
35 #include "src/core/lib/iomgr/exec_ctx.h"
36 #include "src/core/lib/iomgr/tcp_server.h"
37 #include "src/core/lib/iomgr/timer.h"
41 /// Handshakers are used to perform initial handshakes on a connection
42 /// before the client sends the initial request. Some examples of what
43 /// a handshaker can be used for includes support for HTTP CONNECT on
44 /// the client side and various types of security initialization.
46 /// In general, handshakers should be used via a handshake manager.
48 /// Arguments passed through handshakers and to the on_handshake_done callback.
50 /// For handshakers, all members are input/output parameters; for
51 /// example, a handshaker may read from or write to \a endpoint and
52 /// then later replace it with a wrapped endpoint. Similarly, a
53 /// handshaker may modify \a args.
55 /// A handshaker takes ownership of the members while a handshake is in
56 /// progress. Upon failure or shutdown of an in-progress handshaker,
57 /// the handshaker is responsible for destroying the members and setting
58 /// them to NULL before invoking the on_handshake_done callback.
60 /// For the on_handshake_done callback, all members are input arguments,
61 /// which the callback takes ownership of.
62 struct HandshakerArgs {
63 grpc_endpoint* endpoint = nullptr;
64 grpc_channel_args* args = nullptr;
65 grpc_slice_buffer* read_buffer = nullptr;
66 // A handshaker may set this to true before invoking on_handshake_done
67 // to indicate that subsequent handshakers should be skipped.
68 bool exit_early = false;
69 // User data passed through the handshake manager. Not used by
70 // individual handshakers.
71 void* user_data = nullptr;
78 class Handshaker : public RefCounted<Handshaker> {
80 ~Handshaker() override = default;
81 virtual void Shutdown(grpc_error* why) = 0;
82 virtual void DoHandshake(grpc_tcp_server_acceptor* acceptor,
83 grpc_closure* on_handshake_done,
84 HandshakerArgs* args) = 0;
85 virtual const char* name() const = 0;
92 class HandshakeManager : public RefCounted<HandshakeManager> {
95 ~HandshakeManager() override;
97 /// Add \a mgr to the server side list of all pending handshake managers, the
98 /// list starts with \a *head.
99 // Not thread-safe. Caller needs to synchronize.
100 void AddToPendingMgrList(HandshakeManager** head);
102 /// Remove \a mgr from the server side list of all pending handshake managers.
103 // Not thread-safe. Caller needs to synchronize.
104 void RemoveFromPendingMgrList(HandshakeManager** head);
106 /// Shutdown all pending handshake managers starting at head on the server
107 /// side. Not thread-safe. Caller needs to synchronize.
108 void ShutdownAllPending(grpc_error* why);
110 /// Adds a handshaker to the handshake manager.
111 /// Takes ownership of \a handshaker.
112 void Add(RefCountedPtr<Handshaker> handshaker);
114 /// Shuts down the handshake manager (e.g., to clean up when the operation is
115 /// aborted in the middle).
116 void Shutdown(grpc_error* why);
118 /// Invokes handshakers in the order they were added.
119 /// Takes ownership of \a endpoint, and then passes that ownership to
120 /// the \a on_handshake_done callback.
121 /// Does NOT take ownership of \a channel_args. Instead, makes a copy before
122 /// invoking the first handshaker.
123 /// \a acceptor will be nullptr for client-side handshakers.
125 /// When done, invokes \a on_handshake_done with a HandshakerArgs
126 /// object as its argument. If the callback is invoked with error !=
127 /// GRPC_ERROR_NONE, then handshaking failed and the handshaker has done
128 /// the necessary clean-up. Otherwise, the callback takes ownership of
130 void DoHandshake(grpc_endpoint* endpoint,
131 const grpc_channel_args* channel_args, grpc_millis deadline,
132 grpc_tcp_server_acceptor* acceptor,
133 grpc_iomgr_cb_func on_handshake_done, void* user_data);
136 bool CallNextHandshakerLocked(grpc_error* error);
138 // A function used as the handshaker-done callback when chaining
139 // handshakers together.
140 static void CallNextHandshakerFn(void* arg, grpc_error* error);
142 // Callback invoked when deadline is exceeded.
143 static void OnTimeoutFn(void* arg, grpc_error* error);
145 static const size_t HANDSHAKERS_INIT_SIZE = 2;
148 bool is_shutdown_ = false;
149 // An array of handshakers added via grpc_handshake_manager_add().
150 absl::InlinedVector<RefCountedPtr<Handshaker>, HANDSHAKERS_INIT_SIZE>
152 // The index of the handshaker to invoke next and closure to invoke it.
154 grpc_closure call_next_handshaker_;
155 // The acceptor to call the handshakers with.
156 grpc_tcp_server_acceptor* acceptor_;
157 // Deadline timer across all handshakers.
158 grpc_timer deadline_timer_;
159 grpc_closure on_timeout_;
160 // The final callback and user_data to invoke after the last handshaker.
161 grpc_closure on_handshake_done_;
163 HandshakerArgs args_;
164 // Links to the previous and next managers in a list of all pending handshakes
165 // Used at server side only.
166 HandshakeManager* prev_ = nullptr;
167 HandshakeManager* next_ = nullptr;
170 } // namespace grpc_core
172 // TODO(arjunroy): These are transitional to account for the new handshaker API
173 // and will eventually be removed entirely.
174 typedef grpc_core::HandshakeManager grpc_handshake_manager;
175 typedef grpc_core::Handshaker grpc_handshaker;
176 void grpc_handshake_manager_add(grpc_handshake_manager* mgr,
177 grpc_handshaker* handshaker);
179 #endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H */