gfe-relnote: In a QUIC connection, if a write error happens after a successful MTU probe, ignore this error and rollback to the previous MTU before the probe. Protected by --gfe2_reloadable_flag_quic_ignore_one_write_error_after_mtu_probe.
PiperOrigin-RevId: 301825026
Change-Id: Ic1ffd0a0f42ddd5f0b3e314ac8e70a90b9c48609
diff --git a/quic/core/quic_connection.h b/quic/core/quic_connection.h
index e92c876..f86c52c 100644
--- a/quic/core/quic_connection.h
+++ b/quic/core/quic_connection.h
@@ -1434,6 +1434,13 @@
// The number of MTU probes already sent.
size_t mtu_probe_count_;
+ // The value of |long_term_mtu_| prior to the last successful MTU increase.
+ // 0 means either
+ // - MTU discovery has never been enabled, or
+ // - MTU discovery has been enabled, but the connection got a packet write
+ // error with a new (successfully probed) MTU, so it reverted
+ // |long_term_mtu_| to the value before the increase.
+ QuicPacketLength previous_validated_mtu_;
// The value of the MTU regularly used by the connection. This is different
// from the value returned by max_packet_size(), as max_packet_size() returns
// the value of the MTU as currently used by the serializer, so if
