Allow QUIC clients to accept STK/SCFG updates on an existing connection.

net/quic/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 <string>
 
 #include "net/base/net_export.h"
@@ skipping 15 matching lines @@
 
 typedef std::string ServerConfigID;
 
 const QuicTag kCHLO = TAG('C', 'H', 'L', 'O');   // Client hello
 const QuicTag kSHLO = TAG('S', 'H', 'L', 'O');   // Server hello
 const QuicTag kSCFG = TAG('S', 'C', 'F', 'G');   // Server config
 const QuicTag kREJ  = TAG('R', 'E', 'J', '\0');  // Reject
 const QuicTag kCETV = TAG('C', 'E', 'T', 'V');   // Client encrypted tag-value
                                                  // pairs
 const QuicTag kPRST = TAG('P', 'R', 'S', 'T');   // Public reset
+const QuicTag kSCUP = TAG('S', 'C', 'U', 'P');   // Server config update.
 
 // Key exchange methods
 const QuicTag kP256 = TAG('P', '2', '5', '6');   // ECDH, Curve P-256
 const QuicTag kC255 = TAG('C', '2', '5', '5');   // ECDH, Curve25519
 
 // AEAD algorithms
 const QuicTag kNULL = TAG('N', 'U', 'L', 'N');   // null algorithm
 const QuicTag kAESG = TAG('A', 'E', 'S', 'G');   // AES128 + GCM-12
 const QuicTag kCC12 = TAG('C', 'C', '1', '2');   // ChaCha20 + Poly1305
 
@@ skipping 115 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_