relnote: Add a new LazyFack loss detection to QUIC triggered by the LFAK connection option.

net/quic/core/crypto/crypto_protocol.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_CRYPTO_CRYPTO_PROTOCOL_H_
 #define NET_QUIC_CRYPTO_CRYPTO_PROTOCOL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 88 matching lines @@
                                                  // tolerating out of order.
 const QuicTag kSSLR = TAG('S', 'S', 'L', 'R');   // Slow Start Large Reduction.
 const QuicTag kNPRR = TAG('N', 'P', 'R', 'R');   // Pace at unity instead of PRR
 const QuicTag k5RTO = TAG('5', 'R', 'T', 'O');   // Close connection on 5 RTOs
 const QuicTag kCTIM = TAG('C', 'T', 'I', 'M');   // Client timestamp in seconds
                                                  // since UNIX epoch.
 const QuicTag kDHDT = TAG('D', 'H', 'D', 'T');   // Disable HPACK dynamic table.
 const QuicTag kIPFS = TAG('I', 'P', 'F', 'S');   // No Immediate Forward Secrecy
 const QuicTag kCONH = TAG('C', 'O', 'N', 'H');   // Conservative Handshake
                                                  // Retransmissions.
+const QuicTag kLFAK = TAG('L', 'F', 'A', 'K');   // Don't invoke FACK on the
+                                                 // first ack.
 
 // Optional support of truncated Connection IDs.  If sent by a peer, the value
 // is the minimum number of bytes allowed for the connection ID sent to the
 // peer.
 const QuicTag kTCID = TAG('T', 'C', 'I', 'D');   // Connection ID truncation.
 
 // Multipath option.
 const QuicTag kMPTH = TAG('M', 'P', 'T', 'H');   // Enable multipath.
 
 const QuicTag kNCMR = TAG('N', 'C', 'M', 'R');   // Do not attempt connection
@@ skipping 125 matching lines @@
 // amplification factor of any mirror DoS attack.
 //
 // A client may pad an inchoate client hello to a size larger than
 // kClientHelloMinimumSize to make it more likely to receive a complete
 // rejection message.
 const size_t kClientHelloMinimumSize = 1024;
 
 }  // namespace net
 
 #endif  // NET_QUIC_CRYPTO_CRYPTO_PROTOCOL_H_