blob: 6a2253cd64f5770c91c62b8380d1f4ba47a58ff3 [file] [log] [blame]
/*
* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/rtp_rtcp/source/rtp_packet_history.h"
#include <algorithm>
#include <limits>
#include <memory>
#include <utility>
#include "modules/include/module_common_types_public.h"
#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
constexpr size_t RtpPacketHistory::kMaxCapacity;
constexpr size_t RtpPacketHistory::kMaxPaddingtHistory;
constexpr int64_t RtpPacketHistory::kMinPacketDurationMs;
constexpr int RtpPacketHistory::kMinPacketDurationRtt;
constexpr int RtpPacketHistory::kPacketCullingDelayFactor;
RtpPacketHistory::PacketState::PacketState() = default;
RtpPacketHistory::PacketState::PacketState(const PacketState&) = default;
RtpPacketHistory::PacketState::~PacketState() = default;
RtpPacketHistory::StoredPacket::StoredPacket(
std::unique_ptr<RtpPacketToSend> packet,
absl::optional<int64_t> send_time_ms,
uint64_t insert_order)
: send_time_ms_(send_time_ms),
packet_(std::move(packet)),
// No send time indicates packet is not sent immediately, but instead will
// be put in the pacer queue and later retrieved via
// GetPacketAndSetSendTime().
pending_transmission_(!send_time_ms.has_value()),
insert_order_(insert_order),
times_retransmitted_(0) {}
RtpPacketHistory::StoredPacket::StoredPacket(StoredPacket&&) = default;
RtpPacketHistory::StoredPacket& RtpPacketHistory::StoredPacket::operator=(
RtpPacketHistory::StoredPacket&&) = default;
RtpPacketHistory::StoredPacket::~StoredPacket() = default;
void RtpPacketHistory::StoredPacket::IncrementTimesRetransmitted(
PacketPrioritySet* priority_set) {
// Check if this StoredPacket is in the priority set. If so, we need to remove
// it before updating |times_retransmitted_| since that is used in sorting,
// and then add it back.
const bool in_priority_set = priority_set->erase(this) > 0;
++times_retransmitted_;
if (in_priority_set) {
auto it = priority_set->insert(this);
RTC_DCHECK(it.second)
<< "ERROR: Priority set already contains matching packet! In set: "
"insert order = "
<< (*it.first)->insert_order_
<< ", times retransmitted = " << (*it.first)->times_retransmitted_
<< ". Trying to add: insert order = " << insert_order_
<< ", times retransmitted = " << times_retransmitted_;
}
}
bool RtpPacketHistory::MoreUseful::operator()(StoredPacket* lhs,
StoredPacket* rhs) const {
// Prefer to send packets we haven't already sent as padding.
if (lhs->times_retransmitted() != rhs->times_retransmitted()) {
return lhs->times_retransmitted() < rhs->times_retransmitted();
}
// All else being equal, prefer newer packets.
return lhs->insert_order() > rhs->insert_order();
}
RtpPacketHistory::RtpPacketHistory(Clock* clock)
: clock_(clock),
number_to_store_(0),
mode_(StorageMode::kDisabled),
rtt_ms_(-1),
packets_inserted_(0) {}
RtpPacketHistory::~RtpPacketHistory() {}
void RtpPacketHistory::SetStorePacketsStatus(StorageMode mode,
size_t number_to_store) {
RTC_DCHECK_LE(number_to_store, kMaxCapacity);
rtc::CritScope cs(&lock_);
if (mode != StorageMode::kDisabled && mode_ != StorageMode::kDisabled) {
RTC_LOG(LS_WARNING) << "Purging packet history in order to re-set status.";
}
Reset();
mode_ = mode;
number_to_store_ = std::min(kMaxCapacity, number_to_store);
}
RtpPacketHistory::StorageMode RtpPacketHistory::GetStorageMode() const {
rtc::CritScope cs(&lock_);
return mode_;
}
void RtpPacketHistory::SetRtt(int64_t rtt_ms) {
rtc::CritScope cs(&lock_);
RTC_DCHECK_GE(rtt_ms, 0);
rtt_ms_ = rtt_ms;
// If storage is not disabled, packets will be removed after a timeout
// that depends on the RTT. Changing the RTT may thus cause some packets
// become "old" and subject to removal.
if (mode_ != StorageMode::kDisabled) {
CullOldPackets(clock_->TimeInMilliseconds());
}
}
void RtpPacketHistory::PutRtpPacket(std::unique_ptr<RtpPacketToSend> packet,
absl::optional<int64_t> send_time_ms) {
RTC_DCHECK(packet);
rtc::CritScope cs(&lock_);
int64_t now_ms = clock_->TimeInMilliseconds();
if (mode_ == StorageMode::kDisabled) {
return;
}
RTC_DCHECK(packet->allow_retransmission());
CullOldPackets(now_ms);
// Store packet.
const uint16_t rtp_seq_no = packet->SequenceNumber();
int packet_index = GetPacketIndex(rtp_seq_no);
if (packet_index >= 0u &&
static_cast<size_t>(packet_index) < packet_history_.size() &&
packet_history_[packet_index].packet_ != nullptr) {
RTC_LOG(LS_WARNING) << "Duplicate packet inserted: " << rtp_seq_no;
// Remove previous packet to avoid inconsistent state.
RemovePacket(packet_index);
packet_index = GetPacketIndex(rtp_seq_no);
}
// Packet to be inserted ahead of first packet, expand front.
for (; packet_index < 0; ++packet_index) {
packet_history_.emplace_front(nullptr, absl::nullopt, 0);
}
// Packet to be inserted behind last packet, expand back.
while (static_cast<int>(packet_history_.size()) <= packet_index) {
packet_history_.emplace_back(nullptr, absl::nullopt, 0);
}
RTC_DCHECK_GE(packet_index, 0);
RTC_DCHECK_LT(packet_index, packet_history_.size());
RTC_DCHECK(packet_history_[packet_index].packet_ == nullptr);
packet_history_[packet_index] =
StoredPacket(std::move(packet), send_time_ms, packets_inserted_++);
if (padding_priority_.size() >= kMaxPaddingtHistory - 1) {
padding_priority_.erase(std::prev(padding_priority_.end()));
}
auto prio_it = padding_priority_.insert(&packet_history_[packet_index]);
RTC_DCHECK(prio_it.second) << "Failed to insert packet into prio set.";
}
std::unique_ptr<RtpPacketToSend> RtpPacketHistory::GetPacketAndSetSendTime(
uint16_t sequence_number) {
rtc::CritScope cs(&lock_);
if (mode_ == StorageMode::kDisabled) {
return nullptr;
}
StoredPacket* packet = GetStoredPacket(sequence_number);
if (packet == nullptr) {
return nullptr;
}
int64_t now_ms = clock_->TimeInMilliseconds();
if (!VerifyRtt(*packet, now_ms)) {
return nullptr;
}
if (packet->send_time_ms_) {
packet->IncrementTimesRetransmitted(&padding_priority_);
}
// Update send-time and mark as no long in pacer queue.
packet->send_time_ms_ = now_ms;
packet->pending_transmission_ = false;
// Return copy of packet instance since it may need to be retransmitted.
return std::make_unique<RtpPacketToSend>(*packet->packet_);
}
std::unique_ptr<RtpPacketToSend> RtpPacketHistory::GetPacketAndMarkAsPending(
uint16_t sequence_number) {
return GetPacketAndMarkAsPending(
sequence_number, [](const RtpPacketToSend& packet) {
return std::make_unique<RtpPacketToSend>(packet);
});
}
std::unique_ptr<RtpPacketToSend> RtpPacketHistory::GetPacketAndMarkAsPending(
uint16_t sequence_number,
rtc::FunctionView<std::unique_ptr<RtpPacketToSend>(const RtpPacketToSend&)>
encapsulate) {
rtc::CritScope cs(&lock_);
if (mode_ == StorageMode::kDisabled) {
return nullptr;
}
StoredPacket* packet = GetStoredPacket(sequence_number);
if (packet == nullptr) {
return nullptr;
}
if (packet->pending_transmission_) {
// Packet already in pacer queue, ignore this request.
return nullptr;
}
if (!VerifyRtt(*packet, clock_->TimeInMilliseconds())) {
// Packet already resent within too short a time window, ignore.
return nullptr;
}
// Copy and/or encapsulate packet.
std::unique_ptr<RtpPacketToSend> encapsulated_packet =
encapsulate(*packet->packet_);
if (encapsulated_packet) {
packet->pending_transmission_ = true;
}
return encapsulated_packet;
}
void RtpPacketHistory::MarkPacketAsSent(uint16_t sequence_number) {
rtc::CritScope cs(&lock_);
if (mode_ == StorageMode::kDisabled) {
return;
}
StoredPacket* packet = GetStoredPacket(sequence_number);
if (packet == nullptr) {
return;
}
RTC_DCHECK(packet->send_time_ms_);
// Update send-time, mark as no longer in pacer queue, and increment
// transmission count.
packet->send_time_ms_ = clock_->TimeInMilliseconds();
packet->pending_transmission_ = false;
packet->IncrementTimesRetransmitted(&padding_priority_);
}
absl::optional<RtpPacketHistory::PacketState> RtpPacketHistory::GetPacketState(
uint16_t sequence_number) const {
rtc::CritScope cs(&lock_);
if (mode_ == StorageMode::kDisabled) {
return absl::nullopt;
}
int packet_index = GetPacketIndex(sequence_number);
if (packet_index < 0 ||
static_cast<size_t>(packet_index) >= packet_history_.size()) {
return absl::nullopt;
}
const StoredPacket& packet = packet_history_[packet_index];
if (packet.packet_ == nullptr) {
return absl::nullopt;
}
if (!VerifyRtt(packet, clock_->TimeInMilliseconds())) {
return absl::nullopt;
}
return StoredPacketToPacketState(packet);
}
bool RtpPacketHistory::VerifyRtt(const RtpPacketHistory::StoredPacket& packet,
int64_t now_ms) const {
if (packet.send_time_ms_) {
// Send-time already set, this check must be for a retransmission.
if (packet.times_retransmitted() > 0 &&
now_ms < *packet.send_time_ms_ + rtt_ms_) {
// This packet has already been retransmitted once, and the time since
// that even is lower than on RTT. Ignore request as this packet is
// likely already in the network pipe.
return false;
}
}
return true;
}
std::unique_ptr<RtpPacketToSend> RtpPacketHistory::GetPayloadPaddingPacket() {
// Default implementation always just returns a copy of the packet.
return GetPayloadPaddingPacket([](const RtpPacketToSend& packet) {
return std::make_unique<RtpPacketToSend>(packet);
});
}
std::unique_ptr<RtpPacketToSend> RtpPacketHistory::GetPayloadPaddingPacket(
rtc::FunctionView<std::unique_ptr<RtpPacketToSend>(const RtpPacketToSend&)>
encapsulate) {
rtc::CritScope cs(&lock_);
if (mode_ == StorageMode::kDisabled || padding_priority_.empty()) {
return nullptr;
}
auto best_packet_it = padding_priority_.begin();
StoredPacket* best_packet = *best_packet_it;
if (best_packet->pending_transmission_) {
// Because PacedSender releases it's lock when it calls
// GeneratePadding() there is the potential for a race where a new
// packet ends up here instead of the regular transmit path. In such a
// case, just return empty and it will be picked up on the next
// Process() call.
return nullptr;
}
auto padding_packet = encapsulate(*best_packet->packet_);
if (!padding_packet) {
return nullptr;
}
best_packet->send_time_ms_ = clock_->TimeInMilliseconds();
best_packet->IncrementTimesRetransmitted(&padding_priority_);
return padding_packet;
}
void RtpPacketHistory::CullAcknowledgedPackets(
rtc::ArrayView<const uint16_t> sequence_numbers) {
rtc::CritScope cs(&lock_);
for (uint16_t sequence_number : sequence_numbers) {
int packet_index = GetPacketIndex(sequence_number);
if (packet_index < 0 ||
static_cast<size_t>(packet_index) >= packet_history_.size()) {
continue;
}
RemovePacket(packet_index);
}
}
bool RtpPacketHistory::SetPendingTransmission(uint16_t sequence_number) {
rtc::CritScope cs(&lock_);
if (mode_ == StorageMode::kDisabled) {
return false;
}
StoredPacket* packet = GetStoredPacket(sequence_number);
if (packet == nullptr) {
return false;
}
packet->pending_transmission_ = true;
return true;
}
void RtpPacketHistory::Clear() {
rtc::CritScope cs(&lock_);
Reset();
}
void RtpPacketHistory::Reset() {
packet_history_.clear();
padding_priority_.clear();
}
void RtpPacketHistory::CullOldPackets(int64_t now_ms) {
int64_t packet_duration_ms =
std::max(kMinPacketDurationRtt * rtt_ms_, kMinPacketDurationMs);
while (!packet_history_.empty()) {
if (packet_history_.size() >= kMaxCapacity) {
// We have reached the absolute max capacity, remove one packet
// unconditionally.
RemovePacket(0);
continue;
}
const StoredPacket& stored_packet = packet_history_.front();
if (stored_packet.pending_transmission_) {
// Don't remove packets in the pacer queue, pending tranmission.
return;
}
if (*stored_packet.send_time_ms_ + packet_duration_ms > now_ms) {
// Don't cull packets too early to avoid failed retransmission requests.
return;
}
if (packet_history_.size() >= number_to_store_ ||
*stored_packet.send_time_ms_ +
(packet_duration_ms * kPacketCullingDelayFactor) <=
now_ms) {
// Too many packets in history, or this packet has timed out. Remove it
// and continue.
RemovePacket(0);
} else {
// No more packets can be removed right now.
return;
}
}
}
std::unique_ptr<RtpPacketToSend> RtpPacketHistory::RemovePacket(
int packet_index) {
// Move the packet out from the StoredPacket container.
std::unique_ptr<RtpPacketToSend> rtp_packet =
std::move(packet_history_[packet_index].packet_);
// Erase from padding priority set, if eligible.
padding_priority_.erase(&packet_history_[packet_index]);
if (packet_index == 0) {
while (!packet_history_.empty() &&
packet_history_.front().packet_ == nullptr) {
packet_history_.pop_front();
}
}
return rtp_packet;
}
int RtpPacketHistory::GetPacketIndex(uint16_t sequence_number) const {
if (packet_history_.empty()) {
return 0;
}
RTC_DCHECK(packet_history_.front().packet_ != nullptr);
int first_seq = packet_history_.front().packet_->SequenceNumber();
if (first_seq == sequence_number) {
return 0;
}
int packet_index = sequence_number - first_seq;
constexpr int kSeqNumSpan = std::numeric_limits<uint16_t>::max() + 1;
if (IsNewerSequenceNumber(sequence_number, first_seq)) {
if (sequence_number < first_seq) {
// Forward wrap.
packet_index += kSeqNumSpan;
}
} else if (sequence_number > first_seq) {
// Backwards wrap.
packet_index -= kSeqNumSpan;
}
return packet_index;
}
RtpPacketHistory::StoredPacket* RtpPacketHistory::GetStoredPacket(
uint16_t sequence_number) {
int index = GetPacketIndex(sequence_number);
if (index < 0 || static_cast<size_t>(index) >= packet_history_.size() ||
packet_history_[index].packet_ == nullptr) {
return nullptr;
}
return &packet_history_[index];
}
RtpPacketHistory::PacketState RtpPacketHistory::StoredPacketToPacketState(
const RtpPacketHistory::StoredPacket& stored_packet) {
RtpPacketHistory::PacketState state;
state.rtp_sequence_number = stored_packet.packet_->SequenceNumber();
state.send_time_ms = stored_packet.send_time_ms_;
state.capture_time_ms = stored_packet.packet_->capture_time_ms();
state.ssrc = stored_packet.packet_->Ssrc();
state.packet_size = stored_packet.packet_->size();
state.times_retransmitted = stored_packet.times_retransmitted();
state.pending_transmission = stored_packet.pending_transmission_;
return state;
}
} // namespace webrtc