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Diffstat (limited to 'libtransport/src/protocols/rtc/rtc_recovery_strategy.h')
| -rw-r--r-- | libtransport/src/protocols/rtc/rtc_recovery_strategy.h | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/libtransport/src/protocols/rtc/rtc_recovery_strategy.h b/libtransport/src/protocols/rtc/rtc_recovery_strategy.h new file mode 100644 index 000000000..405e1ebba --- /dev/null +++ b/libtransport/src/protocols/rtc/rtc_recovery_strategy.h @@ -0,0 +1,181 @@ +/* + * Copyright (c) 2021 Cisco and/or its affiliates. + * 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. + */ + +#pragma once +#include <hicn/transport/interfaces/callbacks.h> +#include <hicn/transport/utils/chrono_typedefs.h> +#include <protocols/indexer.h> +#include <protocols/rtc/rtc_rc.h> +#include <protocols/rtc/rtc_state.h> + +#include <map> +#include <optional> +#include <unordered_map> + +namespace transport { + +namespace protocol { + +namespace rtc { + +class RecoveryStrategy : public std::enable_shared_from_this<RecoveryStrategy> { + protected: + struct rtx_state_ { + uint64_t first_send_; // first time this interest was sent + uint64_t last_send_; // last time this rtx was sent + uint64_t next_send_; // next retransmission time + uint32_t rtx_count_; // number or rtx + }; + + using rtxState = struct rtx_state_; + + public: + using SendRtxCallback = std::function<void(uint32_t)>; + + RecoveryStrategy(Indexer *indexer, SendRtxCallback &&callback, + asio::io_service &io_service, bool use_rtx, bool use_fec, + interface::RtcTransportRecoveryStrategies rs_type, + interface::StrategyCallback &&external_callback); + + RecoveryStrategy(RecoveryStrategy &&rs); + + virtual ~RecoveryStrategy(); + + void setRtxFec(std::optional<bool> rtx_on = {}, + std::optional<bool> fec_on = {}); + void setState(RTCState *state) { state_ = state; } + void setRateControl(RTCRateControl *rateControl) { rc_ = rateControl; } + void setFecParams(uint32_t n, uint32_t k); + void setContentSharingMode() { content_sharing_mode_ = true; } + + bool isRtx(uint32_t seq) { + if (rtx_state_.find(seq) != rtx_state_.end()) return true; + return false; + } + + bool isPossibleLossWithNoRtx(uint32_t seq) { + if (recover_with_fec_.find(seq) != recover_with_fec_.end()) return true; + return false; + } + + bool wasNacked(uint32_t seq) { + if (nacked_seq_.find(seq) != nacked_seq_.end()) return true; + return false; + } + + interface::RtcTransportRecoveryStrategies getType() { + return rs_type_; + } + void updateType(interface::RtcTransportRecoveryStrategies type) { + rs_type_ = type; + } + bool isRtxOn() { return rtx_on_; } + bool isFecOn() { return fec_on_; } + + RTCState *getState() { return state_; } + + // if the function returns 0 it means that the packet is not an RTX or it is + // not a valid packet to safely compute the RTT + uint64_t getRtxRtt(uint32_t seq); + bool lossDetected(uint32_t seq); + void notifyNewLossDetedcted(uint32_t seq); + void requestPossibleLostPacket(uint32_t seq); + void receivedFutureNack(uint32_t seq); + void clear(); + + virtual void turnOnRecovery() = 0; + virtual void onNewRound(bool in_sync) = 0; + virtual void newPacketLoss(uint32_t seq) = 0; + virtual void receivedPacket(uint32_t seq) = 0; + void onLostTimeout(uint32_t seq); + + void incRoundId() { round_id_++; } + + // utils + uint64_t getNow() { + uint64_t now = utils::SteadyTime::nowMs().count(); + return now; + } + + protected: + // rtx functions + void addNewRtx(uint32_t seq, bool force); + uint64_t computeNextSend(uint32_t seq, uint32_t rtx_counter); + void retransmit(); + void scheduleNextRtx(); + void deleteRtx(uint32_t seq); + + // fec functions + uint32_t computeFecPacketsToAsk(); + + // common functons + void removePacketState(uint32_t seq); + + interface::RtcTransportRecoveryStrategies rs_type_; + bool recovery_on_; + bool rtx_on_; + bool fec_on_; + bool content_sharing_mode_; + + // number of RTX sent after fec turned on + // this is used to take into account jitter and out of order packets + // if we detect losses but we do not sent any RTX it means that the holes in + // the sequence are caused by the jitter + uint32_t rtx_during_fec_; + + // this map keeps track of the retransmitted interest, ordered from the oldest + // to the newest one. the state contains the timer of the first send of the + // interest (from pendingIntetests_), the timer of the next send (key of the + // multimap) and the number of rtx + std::map<uint32_t, rtxState> rtx_state_; + // this map stored the rtx by timer. The key is the time at which the rtx + // should be sent, and the val is the interest seq number + std::multimap<uint64_t, uint32_t> rtx_timers_; + + // lost packets that will be recovered with fec + std::unordered_set<uint32_t> recover_with_fec_; + + // packet for which we recived a future nack + // in case we detect a loss for a nacked packet we send an RTX but we do not + // increase the loss counter. this is done because it may happen that the + // producer rate checkes over time and in flight interest may be satified by + // data packet after the reception of nacks + std::unordered_set<uint32_t> nacked_seq_; + + // rtx vars + std::unique_ptr<asio::steady_timer> timer_; + uint64_t next_rtx_timer_; + SendRtxCallback send_rtx_callback_; + + // fec vars + uint32_t n_; + uint32_t k_; + Indexer *indexer_; + + RTCState *state_; + RTCRateControl *rc_; + + private: + uint32_t round_id_; // number of rounds + uint32_t last_fec_used_; + std::vector<uint32_t> fec_per_loss_rate_; + interface::StrategyCallback callback_; +}; + +} // end namespace rtc + +} // end namespace protocol + +} // end namespace transport |