stats: implement candidate-pair lastPacket(Sent|Received)Timestamp

https://w3c.github.io/webrtc-stats/#dom-rtcicecandidatepairstats-lastpacketsenttimestamp
https://w3c.github.io/webrtc-stats/#dom-rtcicecandidatepairstats-lastpacketreceivedtimestamp

which are useful together with the ice-restart-necessary logic mentioned
in
  https://w3c.github.io/webrtc-pc/#dictionary-rtcofferoptions-members

BUG=webrtc:14619

Change-Id: I4a8ab00a37fbd4af8b948720c83787cbdfc6b9a3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/281281
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Philipp Hancke <phancke@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#38534}

api/stats/rtcstats_objects.h

@@ -222,6 +222,8 @@ class RTC_EXPORT RTCIceCandidatePairStats final : public RTCStats {
   RTCStatsMember<uint64_t> consent_requests_sent;
   RTCStatsMember<uint64_t> packets_discarded_on_send;
   RTCStatsMember<uint64_t> bytes_discarded_on_send;
+  RTCStatsMember<double> last_packet_received_timestamp;
+  RTCStatsMember<double> last_packet_sent_timestamp;
 };
 
 // https://w3c.github.io/webrtc-stats/#icecandidate-dict*

p2p/BUILD.gn

@@ -111,6 +111,7 @@ rtc_library("rtc_p2p") {
     "../api/transport:field_trial_based_config",
     "../api/transport:stun_types",
     "../api/units:time_delta",
+    "../api/units:timestamp",
     "../logging:ice_log",
     "../rtc_base",
     "../rtc_base:async_resolver_interface",

p2p/base/connection.cc

@@ -235,6 +235,7 @@ Connection::Connection(rtc::WeakPtr<Port> port,
       last_ping_response_received_(0),
       state_(IceCandidatePairState::WAITING),
       time_created_ms_(rtc::TimeMillis()),
+      delta_internal_unix_epoch_ms_(rtc::TimeUTCMillis() - rtc::TimeMillis()),
       field_trials_(&kDefaultFieldTrials),
       rtt_estimate_(DEFAULT_RTT_ESTIMATE_HALF_TIME_MS) {
   RTC_DCHECK_RUN_ON(network_thread_);
@@ -1526,6 +1527,14 @@ ConnectionInfo Connection::stats() {
   stats_.total_round_trip_time_ms = total_round_trip_time_ms_;
   stats_.current_round_trip_time_ms = current_round_trip_time_ms_;
   stats_.remote_candidate = remote_candidate();
+  if (last_data_received_ > 0) {
+    stats_.last_data_received = webrtc::Timestamp::Millis(
+        last_data_received_ + delta_internal_unix_epoch_ms_);
+  }
+  if (last_send_data_ > 0) {
+    stats_.last_data_sent = webrtc::Timestamp::Millis(
+        last_send_data_ + delta_internal_unix_epoch_ms_);
+  }
   return stats_;
 }
 

p2p/base/connection.h

@@ -442,7 +442,8 @@ class Connection : public CandidatePairInterface {
   IceCandidatePairState state_ RTC_GUARDED_BY(network_thread_);
   // Time duration to switch from receiving to not receiving.
   absl::optional<int> receiving_timeout_ RTC_GUARDED_BY(network_thread_);
-  int64_t time_created_ms_ RTC_GUARDED_BY(network_thread_);
+  const int64_t time_created_ms_ RTC_GUARDED_BY(network_thread_);
+  const int64_t delta_internal_unix_epoch_ms_ RTC_GUARDED_BY(network_thread_);
   int num_pings_sent_ RTC_GUARDED_BY(network_thread_) = 0;
 
   absl::optional<webrtc::IceCandidatePairDescription> log_description_

p2p/base/connection_info.h

@@ -15,6 +15,7 @@
 
 #include "absl/types/optional.h"
 #include "api/candidate.h"
+#include "api/units/timestamp.h"
 
 namespace cricket {
 
@@ -72,6 +73,10 @@ struct ConnectionInfo {
   uint64_t total_round_trip_time_ms;
   // https://w3c.github.io/webrtc-stats/#dom-rtcicecandidatepairstats-currentroundtriptime
   absl::optional<uint32_t> current_round_trip_time_ms;
+
+  // https://w3c.github.io/webrtc-stats/#dom-rtcicecandidatepairstats-lastpacketreceivedtimestamp
+  absl::optional<webrtc::Timestamp> last_data_received;
+  absl::optional<webrtc::Timestamp> last_data_sent;
 };
 
 // Information about all the candidate pairs of a channel.

pc/rtc_stats_collector.cc

@@ -1727,6 +1727,15 @@ void RTCStatsCollector::ProduceIceCandidateAndPairStats_n(
             info.sent_ping_requests_total -
             info.sent_ping_requests_before_first_response);
 
+        if (info.last_data_received) {
+          candidate_pair_stats->last_packet_received_timestamp =
+              static_cast<double>(info.last_data_received->ms());
+        }
+        if (info.last_data_sent) {
+          candidate_pair_stats->last_packet_sent_timestamp =
+              static_cast<double>(info.last_data_sent->ms());
+        }
+
         report->AddStats(std::move(candidate_pair_stats));
       }
 

pc/rtc_stats_collector_unittest.cc

@@ -1940,6 +1940,8 @@ TEST_F(RTCStatsCollectorTest, CollectRTCIceCandidatePairStats) {
   connection_info.state = cricket::IceCandidatePairState::IN_PROGRESS;
   connection_info.priority = 5555;
   connection_info.nominated = false;
+  connection_info.last_data_received = Timestamp::Millis(2500);
+  connection_info.last_data_sent = Timestamp::Millis(5200);
 
   cricket::TransportChannelStats transport_channel_stats;
   transport_channel_stats.component = cricket::ICE_CANDIDATE_COMPONENT_RTP;
@@ -1974,6 +1976,9 @@ TEST_F(RTCStatsCollectorTest, CollectRTCIceCandidatePairStats) {
   expected_pair.responses_received = 4321;
   expected_pair.responses_sent = 1000;
   expected_pair.consent_requests_sent = (2222 - 2000);
+  expected_pair.last_packet_received_timestamp = 2500;
+  expected_pair.last_packet_sent_timestamp = 5200;
+
   // `expected_pair.current_round_trip_time` should be undefined because the
   // current RTT is not set.
   // `expected_pair.available_[outgoing/incoming]_bitrate` should be undefined

pc/rtc_stats_integrationtest.cc

@@ -516,6 +516,8 @@ class RTCStatsReportVerifier {
     verifier.TestMemberIsNonNegative<uint64_t>(candidate_pair.responses_sent);
     verifier.TestMemberIsNonNegative<uint64_t>(
         candidate_pair.consent_requests_sent);
+    verifier.TestMemberIsDefined(candidate_pair.last_packet_received_timestamp);
+    verifier.TestMemberIsDefined(candidate_pair.last_packet_sent_timestamp);
 
     return verifier.ExpectAllMembersSuccessfullyTested();
   }

stats/rtcstats_objects.cc

@@ -185,7 +185,9 @@ WEBRTC_RTCSTATS_IMPL(RTCIceCandidatePairStats, RTCStats, "candidate-pair",
     &responses_sent,
     &consent_requests_sent,
     &packets_discarded_on_send,
-    &bytes_discarded_on_send)
+    &bytes_discarded_on_send,
+    &last_packet_received_timestamp,
+    &last_packet_sent_timestamp)
 // clang-format on
 
 RTCIceCandidatePairStats::RTCIceCandidatePairStats(const std::string& id,
@@ -216,7 +218,9 @@ RTCIceCandidatePairStats::RTCIceCandidatePairStats(std::string&& id,
       responses_sent("responsesSent"),
       consent_requests_sent("consentRequestsSent"),
       packets_discarded_on_send("packetsDiscardedOnSend"),
-      bytes_discarded_on_send("bytesDiscardedOnSend") {}
+      bytes_discarded_on_send("bytesDiscardedOnSend"),
+      last_packet_received_timestamp("lastPacketReceivedTimestamp"),
+      last_packet_sent_timestamp("lastPacketSentTimestamp") {}
 
 RTCIceCandidatePairStats::RTCIceCandidatePairStats(
     const RTCIceCandidatePairStats& other) = default;