1 // Copyright 2023 gRPC authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef GRPC_SRC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_PING_CALLBACKS_H 16 #define GRPC_SRC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_PING_CALLBACKS_H 17 18 #include <grpc/support/port_platform.h> 19 20 #include <stddef.h> 21 #include <stdint.h> 22 23 #include <algorithm> 24 #include <vector> 25 26 #include "absl/container/flat_hash_map.h" 27 #include "absl/functional/any_invocable.h" 28 #include "absl/hash/hash.h" 29 #include "absl/random/bit_gen_ref.h" 30 #include "absl/types/optional.h" 31 32 #include <grpc/event_engine/event_engine.h> 33 34 #include "src/core/lib/debug/trace.h" 35 #include "src/core/lib/gprpp/time.h" 36 37 extern grpc_core::TraceFlag grpc_ping_trace; 38 39 namespace grpc_core { 40 41 class Chttp2PingCallbacks { 42 public: 43 // One callback from OnPing/OnPingAck or the timeout. 44 using Callback = absl::AnyInvocable<void()>; 45 46 // Request a ping (but one we don't need any notification for when it begins 47 // or ends). RequestPing()48 void RequestPing() { ping_requested_ = true; } 49 50 // Request a ping, and specify callbacks for when it begins and ends. 51 // on_start is invoked during the call to StartPing. 52 // on_ack is invoked during the call to AckPing. 53 void OnPing(Callback on_start, Callback on_ack); 54 55 // Request a notification when *some* ping is acked: 56 // If there is no ping in flight, one will be scheduled and the callback 57 // will be invoked when it is acked. (ie as per OnPing([]{}, on_ack)). 58 // If there is a ping in flight, the callback will be invoked when the most 59 // recently sent ping is acked. 60 // on_ack is invoked during the call to AckPing. 61 void OnPingAck(Callback on_ack); 62 63 // Write path: begin a ping. 64 // Uses bitgen to generate a randomized id for the ping. 65 // Sets started_new_ping_without_setting_timeout. 66 GRPC_MUST_USE_RESULT uint64_t StartPing(absl::BitGenRef bitgen); 67 bool AckPing(uint64_t id, 68 grpc_event_engine::experimental::EventEngine* event_engine); 69 70 // Cancel all the ping callbacks. 71 // Sufficient state is maintained such that AckPing will still return true 72 // if a ping is acked after this call. 73 // No timeouts or start or ack callbacks previously scheduled will be invoked. 74 void CancelAll(grpc_event_engine::experimental::EventEngine* event_engine); 75 76 // Return true if a ping needs to be started due to 77 // RequestPing/OnPing/OnPingAck. ping_requested()78 bool ping_requested() const { return ping_requested_; } 79 80 // Returns the number of pings currently in flight. pings_inflight()81 size_t pings_inflight() const { return inflight_.size(); } 82 83 // Returns true if a ping was started without setting a timeout yet. started_new_ping_without_setting_timeout()84 bool started_new_ping_without_setting_timeout() const { 85 return started_new_ping_without_setting_timeout_; 86 } 87 88 // Add a ping timeout for the most recently started ping. 89 // started_new_ping_without_setting_timeout must be set. 90 // Clears started_new_ping_without_setting_timeout. 91 // Returns the ping id of the ping the timeout was attached to if a timer was 92 // started, or nullopt otherwise. 93 absl::optional<uint64_t> OnPingTimeout( 94 Duration ping_timeout, 95 grpc_event_engine::experimental::EventEngine* event_engine, 96 Callback callback); 97 98 private: 99 using CallbackVec = std::vector<Callback>; 100 struct InflightPing { 101 grpc_event_engine::experimental::EventEngine::TaskHandle on_timeout = 102 grpc_event_engine::experimental::EventEngine::TaskHandle::kInvalid; 103 CallbackVec on_ack; 104 }; 105 absl::flat_hash_map<uint64_t, InflightPing> inflight_; 106 uint64_t most_recent_inflight_ = 0; 107 bool ping_requested_ = false; 108 bool started_new_ping_without_setting_timeout_ = false; 109 CallbackVec on_start_; 110 CallbackVec on_ack_; 111 }; 112 113 } // namespace grpc_core 114 115 #endif // GRPC_SRC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_PING_CALLBACKS_H 116