No public description PiperOrigin-RevId: 673981480

diff --git a/quiche/quic/core/crypto/crypto_protocol.h b/quiche/quic/core/crypto/crypto_protocol.h
index e55af80..83e6ab7 100644
--- a/quiche/quic/core/crypto/crypto_protocol.h
+++ b/quiche/quic/core/crypto/crypto_protocol.h

@@ -490,6 +490,9 @@
                                                     // until the SETTINGS frame
                                                     // is received.
 
+// Enable Failed Path Probe experiment
+const QuicTag kFPPE = TAG('F', 'P', 'P', 'E');
+
 // clang-format on
 
 // These tags have a special form so that they appear either at the beginning

diff --git a/quiche/quic/core/quic_config_test.cc b/quiche/quic/core/quic_config_test.cc
index fbfc486..4cf30e9 100644
--- a/quiche/quic/core/quic_config_test.cc
+++ b/quiche/quic/core/quic_config_test.cc

@@ -623,16 +623,19 @@
 TEST_P(QuicConfigTest, AddConnectionOptionsToSend) {
   QuicTagVector copt;
   copt.push_back(kNOIP);
+  copt.push_back(kFPPE);
   config_.AddConnectionOptionsToSend(copt);
   ASSERT_TRUE(config_.HasSendConnectionOptions());
   EXPECT_TRUE(quic::ContainsQuicTag(config_.SendConnectionOptions(), kNOIP));
+  EXPECT_TRUE(quic::ContainsQuicTag(config_.SendConnectionOptions(), kFPPE));
 
   copt.clear();
   copt.push_back(kSPAD);
   copt.push_back(kSPA2);
   config_.AddConnectionOptionsToSend(copt);
-  ASSERT_EQ(3, config_.SendConnectionOptions().size());
+  ASSERT_EQ(4, config_.SendConnectionOptions().size());
   EXPECT_TRUE(quic::ContainsQuicTag(config_.SendConnectionOptions(), kNOIP));
+  EXPECT_TRUE(quic::ContainsQuicTag(config_.SendConnectionOptions(), kFPPE));
   EXPECT_TRUE(quic::ContainsQuicTag(config_.SendConnectionOptions(), kSPAD));
   EXPECT_TRUE(quic::ContainsQuicTag(config_.SendConnectionOptions(), kSPA2));
 }

diff --git a/quiche/quic/core/quic_connection.cc b/quiche/quic/core/quic_connection.cc
index d13d6a7..d569048 100644
--- a/quiche/quic/core/quic_connection.cc
+++ b/quiche/quic/core/quic_connection.cc

@@ -2166,6 +2166,7 @@
           << "STATELESS_RESET received on alternate path after it's "
              "validated.";
       path_validator_.CancelPathValidation();
+      ++stats_.num_stateless_resets_on_alternate_path;
     } else {
       QUIC_BUG(quic_bug_10511_17)
           << "Received Stateless Reset on unknown socket.";
@@ -6651,6 +6652,10 @@
       reason == PathValidationReason::kMultiPort) {
     multi_port_stats_->num_client_probing_attempts++;
   }
+  if (perspective_ == Perspective::IS_CLIENT) {
+    stats_.num_client_probing_attempts++;
+  }
+
   path_validator_.StartPathValidation(std::move(context),
                                       std::move(result_delegate), reason);
   if (perspective_ == Perspective::IS_CLIENT &&

diff --git a/quiche/quic/core/quic_connection_stats.h b/quiche/quic/core/quic_connection_stats.h
index 80a4f07..0a4a696 100644
--- a/quiche/quic/core/quic_connection_stats.h
+++ b/quiche/quic/core/quic_connection_stats.h

@@ -256,6 +256,10 @@
 
   // The total number of streams which were pending from some time.
   size_t num_total_pending_streams = 0;
+
+  // Statistics to measure how many client path probes are reset.
+  uint32_t num_client_probing_attempts = 0;
+  uint32_t num_stateless_resets_on_alternate_path = 0;
 };
 
 }  // namespace quic

diff --git a/quiche/quic/core/quic_connection_test.cc b/quiche/quic/core/quic_connection_test.cc
index 2f77b1f..33b6002 100644
--- a/quiche/quic/core/quic_connection_test.cc
+++ b/quiche/quic/core/quic_connection_test.cc

@@ -13193,6 +13193,7 @@
   EXPECT_EQ(1, connection_.GetStats().num_path_degrading);
   EXPECT_EQ(1, stats->num_successful_probes);
   EXPECT_EQ(1, stats->num_client_probing_attempts);
+  EXPECT_EQ(1, connection_.GetStats().num_client_probing_attempts);
   EXPECT_EQ(0, stats->num_multi_port_probe_failures_when_path_degrading);
   EXPECT_EQ(kTestRTT, stats->rtt_stats.latest_rtt());
   EXPECT_EQ(kTestRTT,
@@ -13270,6 +13271,7 @@
   EXPECT_EQ(2, connection_.GetStats().num_path_degrading);
   EXPECT_EQ(1, stats->num_multi_port_probe_failures_when_path_degrading);
   EXPECT_EQ(0, stats->num_multi_port_probe_failures_when_path_not_degrading);
+  EXPECT_EQ(0, connection_.GetStats().num_stateless_resets_on_alternate_path);
 }
 
 TEST_P(QuicConnectionTest, TooManyMultiPortPathCreations) {
@@ -13443,6 +13445,8 @@
   EXPECT_CALL(visitor_, OnConnectionClosed(_, ConnectionCloseSource::FROM_PEER))
       .Times(0);
   connection_.ProcessUdpPacket(kNewSelfAddress, kPeerAddress, *received);
+  EXPECT_EQ(connection_.GetStats().num_client_probing_attempts, 1);
+  EXPECT_EQ(connection_.GetStats().num_stateless_resets_on_alternate_path, 1);
 }
 
 // Test that if the client's active migration is disabled, multi-port will not