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/*
* Copyright (c) 2020 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 "rtc_tools/rtc_event_log_visualizer/alerts.h"
#include <stdio.h>
#include <algorithm>
#include <limits>
#include <map>
#include <string>
#include "logging/rtc_event_log/rtc_event_processor.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/sequence_number_unwrapper.h"
#include "rtc_base/strings/string_builder.h"
namespace webrtc {
void TriageHelper::AnalyzeStreamGaps(const ParsedRtcEventLog& parsed_log,
PacketDirection direction) {
// With 100 packets/s (~800kbps), false positives would require 10 s without
// data.
constexpr int64_t kMaxSeqNumJump = 1000;
// With a 90 kHz clock, false positives would require 10 s without data.
constexpr int64_t kTicksPerMillisec = 90;
constexpr int64_t kCaptureTimeGraceMs = 10000;
std::string seq_num_explanation =
direction == kIncomingPacket
? "Incoming RTP sequence number jumps more than 1000. Counter may "
"have been reset or rewritten incorrectly in a group call."
: "Outgoing RTP sequence number jumps more than 1000. Counter may "
"have been reset.";
std::string capture_time_explanation =
direction == kIncomingPacket ? "Incoming capture time jumps more than "
"10s. Clock might have been reset."
: "Outgoing capture time jumps more than "
"10s. Clock might have been reset.";
TriageAlertType seq_num_alert = direction == kIncomingPacket
? TriageAlertType::kIncomingSeqNumJump
: TriageAlertType::kOutgoingSeqNumJump;
TriageAlertType capture_time_alert =
direction == kIncomingPacket ? TriageAlertType::kIncomingCaptureTimeJump
: TriageAlertType::kOutgoingCaptureTimeJump;
const int64_t segment_end_us = parsed_log.first_log_segment().stop_time_us();
// Check for gaps in sequence numbers and capture timestamps.
for (const auto& stream : parsed_log.rtp_packets_by_ssrc(direction)) {
if (IsRtxSsrc(parsed_log, direction, stream.ssrc)) {
continue;
}
auto packets = stream.packet_view;
if (packets.empty()) {
continue;
}
SeqNumUnwrapper<uint16_t> seq_num_unwrapper;
int64_t last_seq_num =
seq_num_unwrapper.Unwrap(packets[0].header.sequenceNumber);
SeqNumUnwrapper<uint32_t> capture_time_unwrapper;
int64_t last_capture_time =
capture_time_unwrapper.Unwrap(packets[0].header.timestamp);
int64_t last_log_time_ms = packets[0].log_time_ms();
for (const auto& packet : packets) {
if (packet.log_time_us() > segment_end_us) {
// Only process the first (LOG_START, LOG_END) segment.
break;
}
int64_t seq_num = seq_num_unwrapper.Unwrap(packet.header.sequenceNumber);
if (std::abs(seq_num - last_seq_num) > kMaxSeqNumJump) {
Alert(seq_num_alert, config_.GetCallTimeSec(packet.log_time()),
seq_num_explanation);
}
last_seq_num = seq_num;
int64_t capture_time =
capture_time_unwrapper.Unwrap(packet.header.timestamp);
if (std::abs(capture_time - last_capture_time) >
kTicksPerMillisec *
(kCaptureTimeGraceMs + packet.log_time_ms() - last_log_time_ms)) {
Alert(capture_time_alert, config_.GetCallTimeSec(packet.log_time()),
capture_time_explanation);
}
last_capture_time = capture_time;
}
}
}
void TriageHelper::AnalyzeTransmissionGaps(const ParsedRtcEventLog& parsed_log,
PacketDirection direction) {
constexpr int64_t kMaxRtpTransmissionGap = 500000;
constexpr int64_t kMaxRtcpTransmissionGap = 3000000;
std::string rtp_explanation =
direction == kIncomingPacket
? "No RTP packets received for more than 500ms. This indicates a "
"network problem. Temporary video freezes and choppy or robotic "
"audio is unavoidable. Unnecessary BWE drops is a known issue."
: "No RTP packets sent for more than 500 ms. This might be an issue "
"with the pacer.";
std::string rtcp_explanation =
direction == kIncomingPacket
? "No RTCP packets received for more than 3 s. Could be a longer "
"connection outage"
: "No RTCP packets sent for more than 3 s. This is most likely a "
"bug.";
TriageAlertType rtp_alert = direction == kIncomingPacket
? TriageAlertType::kIncomingRtpGap
: TriageAlertType::kOutgoingRtpGap;
TriageAlertType rtcp_alert = direction == kIncomingPacket
? TriageAlertType::kIncomingRtcpGap
: TriageAlertType::kOutgoingRtcpGap;
const int64_t segment_end_us = parsed_log.first_log_segment().stop_time_us();
// TODO(terelius): The parser could provide a list of all packets, ordered
// by time, for each direction.
std::multimap<int64_t, const LoggedRtpPacket*> rtp_in_direction;
for (const auto& stream : parsed_log.rtp_packets_by_ssrc(direction)) {
for (const LoggedRtpPacket& rtp_packet : stream.packet_view)
rtp_in_direction.emplace(rtp_packet.log_time_us(), &rtp_packet);
}
absl::optional<int64_t> last_rtp_time;
for (const auto& kv : rtp_in_direction) {
int64_t timestamp = kv.first;
if (timestamp > segment_end_us) {
// Only process the first (LOG_START, LOG_END) segment.
break;
}
int64_t duration = timestamp - last_rtp_time.value_or(0);
if (last_rtp_time.has_value() && duration > kMaxRtpTransmissionGap) {
// No packet sent/received for more than 500 ms.
Alert(rtp_alert, config_.GetCallTimeSec(Timestamp::Micros(timestamp)),
rtp_explanation);
}
last_rtp_time.emplace(timestamp);
}
absl::optional<int64_t> last_rtcp_time;
if (direction == kIncomingPacket) {
for (const auto& rtcp : parsed_log.incoming_rtcp_packets()) {
if (rtcp.log_time_us() > segment_end_us) {
// Only process the first (LOG_START, LOG_END) segment.
break;
}
int64_t duration = rtcp.log_time_us() - last_rtcp_time.value_or(0);
if (last_rtcp_time.has_value() && duration > kMaxRtcpTransmissionGap) {
// No feedback sent/received for more than 2000 ms.
Alert(rtcp_alert, config_.GetCallTimeSec(rtcp.log_time()),
rtcp_explanation);
}
last_rtcp_time.emplace(rtcp.log_time_us());
}
} else {
for (const auto& rtcp : parsed_log.outgoing_rtcp_packets()) {
if (rtcp.log_time_us() > segment_end_us) {
// Only process the first (LOG_START, LOG_END) segment.
break;
}
int64_t duration = rtcp.log_time_us() - last_rtcp_time.value_or(0);
if (last_rtcp_time.has_value() && duration > kMaxRtcpTransmissionGap) {
// No feedback sent/received for more than 2000 ms.
Alert(rtcp_alert, config_.GetCallTimeSec(rtcp.log_time()),
rtcp_explanation);
}
last_rtcp_time.emplace(rtcp.log_time_us());
}
}
}
// TODO(terelius): Notifications could possibly be generated by the same code
// that produces the graphs. There is some code duplication that could be
// avoided, but that might be solved anyway when we move functionality from the
// analyzer to the parser.
void TriageHelper::AnalyzeLog(const ParsedRtcEventLog& parsed_log) {
AnalyzeStreamGaps(parsed_log, kIncomingPacket);
AnalyzeStreamGaps(parsed_log, kOutgoingPacket);
AnalyzeTransmissionGaps(parsed_log, kIncomingPacket);
AnalyzeTransmissionGaps(parsed_log, kOutgoingPacket);
const int64_t segment_end_us = parsed_log.first_log_segment().stop_time_us();
Timestamp first_occurrence = parsed_log.last_timestamp();
constexpr double kMaxLossFraction = 0.05;
// Loss feedback
int64_t total_lost_packets = 0;
int64_t total_expected_packets = 0;
for (auto& bwe_update : parsed_log.bwe_loss_updates()) {
if (bwe_update.log_time_us() > segment_end_us) {
// Only process the first (LOG_START, LOG_END) segment.
break;
}
int64_t lost_packets = static_cast<double>(bwe_update.fraction_lost) / 255 *
bwe_update.expected_packets;
total_lost_packets += lost_packets;
total_expected_packets += bwe_update.expected_packets;
if (bwe_update.fraction_lost >= 255 * kMaxLossFraction) {
first_occurrence = std::min(first_occurrence, bwe_update.log_time());
}
}
double avg_outgoing_loss =
static_cast<double>(total_lost_packets) / total_expected_packets;
if (avg_outgoing_loss > kMaxLossFraction) {
Alert(TriageAlertType::kOutgoingHighLoss,
config_.GetCallTimeSec(first_occurrence),
"More than 5% of outgoing packets lost.");
}
}
void TriageHelper::Print(FILE* file) {
fprintf(file, "========== TRIAGE NOTIFICATIONS ==========\n");
for (const auto& alert : triage_alerts_) {
fprintf(file, "%d %s. First occurrence at %3.3lf\n", alert.second.count,
alert.second.explanation.c_str(), alert.second.first_occurrence);
}
fprintf(file, "========== END TRIAGE NOTIFICATIONS ==========\n");
}
void TriageHelper::ProcessAlerts(
std::function<void(int, float, std::string)> f) {
for (const auto& alert : triage_alerts_) {
f(alert.second.count, alert.second.first_occurrence,
alert.second.explanation);
}
}
} // namespace webrtc
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