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_RATE_POLICY_H 16 #define GRPC_SRC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_PING_RATE_POLICY_H 17 18 #include <grpc/support/port_platform.h> 19 20 #include <stddef.h> 21 22 #include <iosfwd> 23 #include <string> 24 25 #include "absl/types/variant.h" 26 27 #include "src/core/lib/channel/channel_args.h" 28 #include "src/core/lib/gprpp/time.h" 29 30 namespace grpc_core { 31 32 class Chttp2PingRatePolicy { 33 public: 34 explicit Chttp2PingRatePolicy(const ChannelArgs& args, bool is_client); 35 36 static void SetDefaults(const ChannelArgs& args); 37 38 struct SendGranted { 39 bool operator==(const SendGranted&) const { return true; } 40 }; 41 struct TooManyRecentPings { 42 bool operator==(const TooManyRecentPings&) const { return true; } 43 }; 44 struct TooSoon { 45 Duration next_allowed_ping_interval; 46 Timestamp last_ping; 47 Duration wait; 48 bool operator==(const TooSoon& other) const { 49 return next_allowed_ping_interval == other.next_allowed_ping_interval && 50 last_ping == other.last_ping && wait == other.wait; 51 } 52 }; 53 using RequestSendPingResult = 54 absl::variant<SendGranted, TooManyRecentPings, TooSoon>; 55 56 // Request that one ping be sent. 57 // Returns: 58 // - SendGranted if a ping can be sent. 59 // - TooManyRecentPings if too many pings have been sent recently and we 60 // should wait for some future write. 61 // - TooSoon if we should wait for some time before sending the ping. 62 RequestSendPingResult RequestSendPing(Duration next_allowed_ping_interval, 63 size_t inflight_pings) const; 64 // Notify the policy that one ping has been sent. 65 void SentPing(); 66 // Notify the policy that some data has been sent and so we should no longer 67 // block pings on that basis. 68 void ResetPingsBeforeDataRequired(); 69 // Notify the policy that we've received some data. 70 void ReceivedDataFrame(); 71 std::string GetDebugString() const; 72 TestOnlyMaxPingsWithoutData()73 int TestOnlyMaxPingsWithoutData() const { return max_pings_without_data_; } 74 75 private: 76 const int max_pings_without_data_; 77 const int max_inflight_pings_; 78 // No pings allowed before receiving a header or data frame. 79 int pings_before_data_required_ = 0; 80 Timestamp last_ping_sent_time_ = Timestamp::InfPast(); 81 }; 82 83 std::ostream& operator<<(std::ostream& out, 84 const Chttp2PingRatePolicy::RequestSendPingResult& r); 85 86 } // namespace grpc_core 87 88 #endif // GRPC_SRC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_PING_RATE_POLICY_H 89