draft-ietf-quic-transport-11.txt   draft-ietf-quic-transport-12.txt 
QUIC J. Iyengar, Ed. QUIC J. Iyengar, Ed.
Internet-Draft Fastly Internet-Draft Fastly
Intended status: Standards Track M. Thomson, Ed. Intended status: Standards Track M. Thomson, Ed.
Expires: October 19, 2018 Mozilla Expires: November 23, 2018 Mozilla
April 17, 2018 May 22, 2018
QUIC: A UDP-Based Multiplexed and Secure Transport QUIC: A UDP-Based Multiplexed and Secure Transport
draft-ietf-quic-transport-11 draft-ietf-quic-transport-12
Abstract Abstract
This document defines the core of the QUIC transport protocol. This This document defines the core of the QUIC transport protocol. This
document describes connection establishment, packet format, document describes connection establishment, packet format,
multiplexing and reliability. Accompanying documents describe the multiplexing and reliability. Accompanying documents describe the
cryptographic handshake and loss detection. cryptographic handshake and loss detection.
Note to Readers Note to Readers
Discussion of this draft takes place on the QUIC working group Discussion of this draft takes place on the QUIC working group
mailing list (quic@ietf.org), which is archived at mailing list (quic@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/search/?email_list=quic [1]. <https://mailarchive.ietf.org/arch/search/?email_list=quic>.
Working Group information can be found at https://github.com/quicwg Working Group information can be found at <https://github.com/
[2]; source code and issues list for this draft can be found at quicwg>; source code and issues list for this draft can be found at
https://github.com/quicwg/base-drafts/labels/-transport [3]. <https://github.com/quicwg/base-drafts/labels/-transport>.
Status of This Memo Status of This Memo
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This Internet-Draft will expire on October 19, 2018. This Internet-Draft will expire on November 23, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 6 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 6
2.1. Notational Conventions . . . . . . . . . . . . . . . . . 6 2.1. Notational Conventions . . . . . . . . . . . . . . . . . 6
3. Versions . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. Versions . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Packet Types and Formats . . . . . . . . . . . . . . . . . . 8 4. Packet Types and Formats . . . . . . . . . . . . . . . . . . 8
4.1. Long Header . . . . . . . . . . . . . . . . . . . . . . . 8 4.1. Long Header . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. Short Header . . . . . . . . . . . . . . . . . . . . . . 10 4.2. Short Header . . . . . . . . . . . . . . . . . . . . . . 10
4.3. Version Negotiation Packet . . . . . . . . . . . . . . . 12 4.3. Version Negotiation Packet . . . . . . . . . . . . . . . 12
4.4. Cryptographic Handshake Packets . . . . . . . . . . . . . 14 4.4. Cryptographic Handshake Packets . . . . . . . . . . . . . 13
4.4.1. Initial Packet . . . . . . . . . . . . . . . . . . . 14 4.4.1. Initial Packet . . . . . . . . . . . . . . . . . . . 13
4.4.2. Retry Packet . . . . . . . . . . . . . . . . . . . . 15 4.4.2. Retry Packet . . . . . . . . . . . . . . . . . . . . 14
4.4.3. Handshake Packet . . . . . . . . . . . . . . . . . . 16 4.4.3. Handshake Packet . . . . . . . . . . . . . . . . . . 15
4.5. Protected Packets . . . . . . . . . . . . . . . . . . . . 17 4.5. Protected Packets . . . . . . . . . . . . . . . . . . . . 16
4.6. Coaslescing Packets . . . . . . . . . . . . . . . . . . . 17 4.6. Coalescing Packets . . . . . . . . . . . . . . . . . . . 17
4.7. Connection ID . . . . . . . . . . . . . . . . . . . . . . 18 4.7. Connection ID . . . . . . . . . . . . . . . . . . . . . . 17
4.8. Packet Numbers . . . . . . . . . . . . . . . . . . . . . 19 4.8. Packet Numbers . . . . . . . . . . . . . . . . . . . . . 18
4.8.1. Initial Packet Number . . . . . . . . . . . . . . . . 20
5. Frames and Frame Types . . . . . . . . . . . . . . . . . . . 20 5. Frames and Frame Types . . . . . . . . . . . . . . . . . . . 20
6. Life of a Connection . . . . . . . . . . . . . . . . . . . . 22 6. Life of a Connection . . . . . . . . . . . . . . . . . . . . 22
6.1. Matching Packets to Connections . . . . . . . . . . . . . 23 6.1. Matching Packets to Connections . . . . . . . . . . . . . 23
6.1.1. Client Packet Handling . . . . . . . . . . . . . . . 23 6.1.1. Client Packet Handling . . . . . . . . . . . . . . . 23
6.1.2. Server Packet Handling . . . . . . . . . . . . . . . 23 6.1.2. Server Packet Handling . . . . . . . . . . . . . . . 23
6.2. Version Negotiation . . . . . . . . . . . . . . . . . . . 24 6.2. Version Negotiation . . . . . . . . . . . . . . . . . . . 24
6.2.1. Sending Version Negotiation Packets . . . . . . . . . 25 6.2.1. Sending Version Negotiation Packets . . . . . . . . . 25
6.2.2. Handling Version Negotiation Packets . . . . . . . . 25 6.2.2. Handling Version Negotiation Packets . . . . . . . . 25
6.2.3. Using Reserved Versions . . . . . . . . . . . . . . . 26 6.2.3. Using Reserved Versions . . . . . . . . . . . . . . . 26
6.3. Cryptographic and Transport Handshake . . . . . . . . . . 26 6.3. Cryptographic and Transport Handshake . . . . . . . . . . 26
6.4. Transport Parameters . . . . . . . . . . . . . . . . . . 27 6.4. Transport Parameters . . . . . . . . . . . . . . . . . . 27
6.4.1. Transport Parameter Definitions . . . . . . . . . . . 29 6.4.1. Transport Parameter Definitions . . . . . . . . . . . 29
6.4.2. Values of Transport Parameters for 0-RTT . . . . . . 30 6.4.2. Values of Transport Parameters for 0-RTT . . . . . . 31
6.4.3. New Transport Parameters . . . . . . . . . . . . . . 31 6.4.3. New Transport Parameters . . . . . . . . . . . . . . 31
6.4.4. Version Negotiation Validation . . . . . . . . . . . 31 6.4.4. Version Negotiation Validation . . . . . . . . . . . 32
6.5. Stateless Retries . . . . . . . . . . . . . . . . . . . . 33 6.5. Stateless Retries . . . . . . . . . . . . . . . . . . . . 33
6.6. Proof of Source Address Ownership . . . . . . . . . . . . 33 6.6. Proof of Source Address Ownership . . . . . . . . . . . . 34
6.6.1. Client Address Validation Procedure . . . . . . . . . 34 6.6.1. Client Address Validation Procedure . . . . . . . . . 34
6.6.2. Address Validation on Session Resumption . . . . . . 35 6.6.2. Address Validation on Session Resumption . . . . . . 35
6.6.3. Address Validation Token Integrity . . . . . . . . . 35 6.6.3. Address Validation Token Integrity . . . . . . . . . 36
6.7. Path Validation . . . . . . . . . . . . . . . . . . . . . 36 6.7. Path Validation . . . . . . . . . . . . . . . . . . . . . 36
6.7.1. Initiation . . . . . . . . . . . . . . . . . . . . . 36 6.7.1. Initiation . . . . . . . . . . . . . . . . . . . . . 37
6.7.2. Response . . . . . . . . . . . . . . . . . . . . . . 37 6.7.2. Response . . . . . . . . . . . . . . . . . . . . . . 37
6.7.3. Completion . . . . . . . . . . . . . . . . . . . . . 37 6.7.3. Completion . . . . . . . . . . . . . . . . . . . . . 38
6.7.4. Abandonment . . . . . . . . . . . . . . . . . . . . . 38 6.7.4. Abandonment . . . . . . . . . . . . . . . . . . . . . 38
6.8. Connection Migration . . . . . . . . . . . . . . . . . . 38 6.8. Connection Migration . . . . . . . . . . . . . . . . . . 39
6.8.1. Probing a New Path . . . . . . . . . . . . . . . . . 38 6.8.1. Probing a New Path . . . . . . . . . . . . . . . . . 39
6.8.2. Initiating Connection Migration . . . . . . . . . . . 39 6.8.2. Initiating Connection Migration . . . . . . . . . . . 39
6.8.3. Responding to Connection Migration . . . . . . . . . 39 6.8.3. Responding to Connection Migration . . . . . . . . . 40
6.8.4. Loss Detection and Congestion Control . . . . . . . . 41 6.8.4. Loss Detection and Congestion Control . . . . . . . . 42
6.8.5. Privacy Implications of Connection Migration . . . . 42 6.8.5. Privacy Implications of Connection Migration . . . . 42
6.9. Connection Termination . . . . . . . . . . . . . . . . . 43 6.9. Server's Preferred Address . . . . . . . . . . . . . . . 44
6.9.1. Closing and Draining Connection States . . . . . . . 44 6.9.1. Communicating A Preferred Address . . . . . . . . . . 44
6.9.2. Idle Timeout . . . . . . . . . . . . . . . . . . . . 45 6.9.2. Responding to Connection Migration . . . . . . . . . 44
6.9.3. Immediate Close . . . . . . . . . . . . . . . . . . . 45 6.9.3. Interaction of Client Migration and Preferred Address 45
6.9.4. Stateless Reset . . . . . . . . . . . . . . . . . . . 46 6.10. Connection Termination . . . . . . . . . . . . . . . . . 45
7. Frame Types and Formats . . . . . . . . . . . . . . . . . . . 49 6.10.1. Closing and Draining Connection States . . . . . . . 45
7.1. Variable-Length Integer Encoding . . . . . . . . . . . . 49 6.10.2. Idle Timeout . . . . . . . . . . . . . . . . . . . . 47
7.2. PADDING Frame . . . . . . . . . . . . . . . . . . . . . . 50 6.10.3. Immediate Close . . . . . . . . . . . . . . . . . . 47
7.3. RST_STREAM Frame . . . . . . . . . . . . . . . . . . . . 50 6.10.4. Stateless Reset . . . . . . . . . . . . . . . . . . 48
7.4. CONNECTION_CLOSE frame . . . . . . . . . . . . . . . . . 51 7. Frame Types and Formats . . . . . . . . . . . . . . . . . . . 51
7.5. APPLICATION_CLOSE frame . . . . . . . . . . . . . . . . . 52 7.1. Variable-Length Integer Encoding . . . . . . . . . . . . 51
7.6. MAX_DATA Frame . . . . . . . . . . . . . . . . . . . . . 52 7.2. PADDING Frame . . . . . . . . . . . . . . . . . . . . . . 52
7.7. MAX_STREAM_DATA Frame . . . . . . . . . . . . . . . . . . 53 7.3. RST_STREAM Frame . . . . . . . . . . . . . . . . . . . . 52
7.8. MAX_STREAM_ID Frame . . . . . . . . . . . . . . . . . . . 54 7.4. CONNECTION_CLOSE frame . . . . . . . . . . . . . . . . . 53
7.9. PING Frame . . . . . . . . . . . . . . . . . . . . . . . 54 7.5. APPLICATION_CLOSE frame . . . . . . . . . . . . . . . . . 53
7.10. BLOCKED Frame . . . . . . . . . . . . . . . . . . . . . . 55 7.6. MAX_DATA Frame . . . . . . . . . . . . . . . . . . . . . 54
7.11. STREAM_BLOCKED Frame . . . . . . . . . . . . . . . . . . 55 7.7. MAX_STREAM_DATA Frame . . . . . . . . . . . . . . . . . . 54
7.12. STREAM_ID_BLOCKED Frame . . . . . . . . . . . . . . . . . 56 7.8. MAX_STREAM_ID Frame . . . . . . . . . . . . . . . . . . . 55
7.13. NEW_CONNECTION_ID Frame . . . . . . . . . . . . . . . . . 56 7.9. PING Frame . . . . . . . . . . . . . . . . . . . . . . . 56
7.14. STOP_SENDING Frame . . . . . . . . . . . . . . . . . . . 58 7.10. BLOCKED Frame . . . . . . . . . . . . . . . . . . . . . . 57
7.15. ACK Frame . . . . . . . . . . . . . . . . . . . . . . . . 58 7.11. STREAM_BLOCKED Frame . . . . . . . . . . . . . . . . . . 57
7.15.1. ACK Block Section . . . . . . . . . . . . . . . . . 60 7.12. STREAM_ID_BLOCKED Frame . . . . . . . . . . . . . . . . . 58
7.15.2. Sending ACK Frames . . . . . . . . . . . . . . . . . 61 7.13. NEW_CONNECTION_ID Frame . . . . . . . . . . . . . . . . . 58
7.15.3. ACK Frames and Packet Protection . . . . . . . . . . 62 7.14. STOP_SENDING Frame . . . . . . . . . . . . . . . . . . . 59
7.16. PATH_CHALLENGE Frame . . . . . . . . . . . . . . . . . . 63 7.15. ACK Frame . . . . . . . . . . . . . . . . . . . . . . . . 60
7.17. PATH_RESPONSE Frame . . . . . . . . . . . . . . . . . . . 63 7.15.1. ACK Block Section . . . . . . . . . . . . . . . . . 61
7.18. STREAM Frames . . . . . . . . . . . . . . . . . . . . . . 64 7.15.2. Sending ACK Frames . . . . . . . . . . . . . . . . . 63
8. Packetization and Reliability . . . . . . . . . . . . . . . . 65 7.15.3. ACK Frames and Packet Protection . . . . . . . . . . 64
8.1. Packet Processing and Acknowledgment . . . . . . . . . . 66 7.16. PATH_CHALLENGE Frame . . . . . . . . . . . . . . . . . . 65
8.2. Retransmission of Information . . . . . . . . . . . . . . 66 7.17. PATH_RESPONSE Frame . . . . . . . . . . . . . . . . . . . 65
8.3. Packet Size . . . . . . . . . . . . . . . . . . . . . . . 68 7.18. STREAM Frames . . . . . . . . . . . . . . . . . . . . . . 65
8.4. Path Maximum Transmission Unit . . . . . . . . . . . . . 68 8. Packetization and Reliability . . . . . . . . . . . . . . . . 67
8.4.1. Special Considerations for PMTU Discovery . . . . . . 69 8.1. Packet Processing and Acknowledgment . . . . . . . . . . 67
8.2. Retransmission of Information . . . . . . . . . . . . . . 68
8.3. Packet Size . . . . . . . . . . . . . . . . . . . . . . . 70
8.4. Path Maximum Transmission Unit . . . . . . . . . . . . . 70
8.4.1. Special Considerations for PMTU Discovery . . . . . . 71
8.4.2. Special Considerations for Packetization Layer PMTU 8.4.2. Special Considerations for Packetization Layer PMTU
Discovery . . . . . . . . . . . . . . . . . . . . . . 70 Discovery . . . . . . . . . . . . . . . . . . . . . . 71
9. Streams: QUIC's Data Structuring Abstraction . . . . . . . . 70 9. Streams: QUIC's Data Structuring Abstraction . . . . . . . . 72
9.1. Stream Identifiers . . . . . . . . . . . . . . . . . . . 71 9.1. Stream Identifiers . . . . . . . . . . . . . . . . . . . 73
9.2. Stream States . . . . . . . . . . . . . . . . . . . . . . 72 9.2. Stream States . . . . . . . . . . . . . . . . . . . . . . 74
9.2.1. Send Stream States . . . . . . . . . . . . . . . . . 73 9.2.1. Send Stream States . . . . . . . . . . . . . . . . . 74
9.2.2. Receive Stream States . . . . . . . . . . . . . . . . 75 9.2.2. Receive Stream States . . . . . . . . . . . . . . . . 76
9.2.3. Permitted Frame Types . . . . . . . . . . . . . . . . 77 9.2.3. Permitted Frame Types . . . . . . . . . . . . . . . . 79
9.2.4. Bidirectional Stream States . . . . . . . . . . . . . 77 9.2.4. Bidirectional Stream States . . . . . . . . . . . . . 79
9.3. Solicited State Transitions . . . . . . . . . . . . . . . 78 9.3. Solicited State Transitions . . . . . . . . . . . . . . . 80
9.4. Stream Concurrency . . . . . . . . . . . . . . . . . . . 79 9.4. Stream Concurrency . . . . . . . . . . . . . . . . . . . 81
9.5. Sending and Receiving Data . . . . . . . . . . . . . . . 80 9.5. Sending and Receiving Data . . . . . . . . . . . . . . . 82
9.6. Stream Prioritization . . . . . . . . . . . . . . . . . . 80 9.6. Stream Prioritization . . . . . . . . . . . . . . . . . . 82
10. Flow Control . . . . . . . . . . . . . . . . . . . . . . . . 81 10. Flow Control . . . . . . . . . . . . . . . . . . . . . . . . 83
10.1. Edge Cases and Other Considerations . . . . . . . . . . 83 10.1. Edge Cases and Other Considerations . . . . . . . . . . 85
10.1.1. Response to a RST_STREAM . . . . . . . . . . . . . . 83 10.1.1. Response to a RST_STREAM . . . . . . . . . . . . . . 85
10.1.2. Data Limit Increments . . . . . . . . . . . . . . . 83 10.1.2. Data Limit Increments . . . . . . . . . . . . . . . 85
10.1.3. Handshake Exemption . . . . . . . . . . . . . . . . 84 10.1.3. Handshake Exemption . . . . . . . . . . . . . . . . 86
10.2. Stream Limit Increment . . . . . . . . . . . . . . . . . 84 10.2. Stream Limit Increment . . . . . . . . . . . . . . . . . 86
10.2.1. Blocking on Flow Control . . . . . . . . . . . . . . 84 10.2.1. Blocking on Flow Control . . . . . . . . . . . . . . 86
10.3. Stream Final Offset . . . . . . . . . . . . . . . . . . 85 10.3. Stream Final Offset . . . . . . . . . . . . . . . . . . 87
11. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 85 11. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 87
11.1. Connection Errors . . . . . . . . . . . . . . . . . . . 86 11.1. Connection Errors . . . . . . . . . . . . . . . . . . . 88
11.2. Stream Errors . . . . . . . . . . . . . . . . . . . . . 87 11.2. Stream Errors . . . . . . . . . . . . . . . . . . . . . 89
11.3. Transport Error Codes . . . . . . . . . . . . . . . . . 87 11.3. Transport Error Codes . . . . . . . . . . . . . . . . . 89
11.4. Application Protocol Error Codes . . . . . . . . . . . . 88 11.4. Application Protocol Error Codes . . . . . . . . . . . . 90
12. Security and Privacy Considerations . . . . . . . . . . . . . 89 12. Security Considerations . . . . . . . . . . . . . . . . . . . 91
12.1. Spoofed ACK Attack . . . . . . . . . . . . . . . . . . . 89 12.1. Spoofed ACK Attack . . . . . . . . . . . . . . . . . . . 91
12.2. Optimistic ACK Attack . . . . . . . . . . . . . . . . . 89 12.2. Optimistic ACK Attack . . . . . . . . . . . . . . . . . 91
12.3. Slowloris Attacks . . . . . . . . . . . . . . . . . . . 90 12.3. Slowloris Attacks . . . . . . . . . . . . . . . . . . . 92
12.4. Stream Fragmentation and Reassembly Attacks . . . . . . 90 12.4. Stream Fragmentation and Reassembly Attacks . . . . . . 92
12.5. Stream Commitment Attack . . . . . . . . . . . . . . . . 90 12.5. Stream Commitment Attack . . . . . . . . . . . . . . . . 92
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 91 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 93
13.1. QUIC Transport Parameter Registry . . . . . . . . . . . 91 13.1. QUIC Transport Parameter Registry . . . . . . . . . . . 93
13.2. QUIC Transport Error Codes Registry . . . . . . . . . . 92 13.2. QUIC Transport Error Codes Registry . . . . . . . . . . 94
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 94 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 96
14.1. Normative References . . . . . . . . . . . . . . . . . . 94 14.1. Normative References . . . . . . . . . . . . . . . . . . 96
14.2. Informative References . . . . . . . . . . . . . . . . . 95 14.2. Informative References . . . . . . . . . . . . . . . . . 97
14.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 98
Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 96 Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 98
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 97 Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 99
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 97 C.1. Since draft-ietf-quic-transport-11 . . . . . . . . . . . 99
C.1. Since draft-ietf-quic-transport-10 . . . . . . . . . . . 97 C.2. Since draft-ietf-quic-transport-10 . . . . . . . . . . . 99
C.2. Since draft-ietf-quic-transport-09 . . . . . . . . . . . 98 C.3. Since draft-ietf-quic-transport-09 . . . . . . . . . . . 100
C.3. Since draft-ietf-quic-transport-08 . . . . . . . . . . . 98 C.4. Since draft-ietf-quic-transport-08 . . . . . . . . . . . 100
C.4. Since draft-ietf-quic-transport-07 . . . . . . . . . . . 99 C.5. Since draft-ietf-quic-transport-07 . . . . . . . . . . . 101
C.5. Since draft-ietf-quic-transport-06 . . . . . . . . . . . 100 C.6. Since draft-ietf-quic-transport-06 . . . . . . . . . . . 102
C.6. Since draft-ietf-quic-transport-05 . . . . . . . . . . . 100 C.7. Since draft-ietf-quic-transport-05 . . . . . . . . . . . 102
C.7. Since draft-ietf-quic-transport-04 . . . . . . . . . . . 100 C.8. Since draft-ietf-quic-transport-04 . . . . . . . . . . . 102
C.8. Since draft-ietf-quic-transport-03 . . . . . . . . . . . 101 C.9. Since draft-ietf-quic-transport-03 . . . . . . . . . . . 103
C.9. Since draft-ietf-quic-transport-02 . . . . . . . . . . . 101 C.10. Since draft-ietf-quic-transport-02 . . . . . . . . . . . 103
C.10. Since draft-ietf-quic-transport-01 . . . . . . . . . . . 102 C.11. Since draft-ietf-quic-transport-01 . . . . . . . . . . . 104
C.11. Since draft-ietf-quic-transport-00 . . . . . . . . . . . 104 C.12. Since draft-ietf-quic-transport-00 . . . . . . . . . . . 106
C.12. Since draft-hamilton-quic-transport-protocol-01 . . . . . 104 C.13. Since draft-hamilton-quic-transport-protocol-01 . . . . . 106
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 105 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 107
1. Introduction 1. Introduction
QUIC is a multiplexed and secure transport protocol that runs on top QUIC is a multiplexed and secure transport protocol that runs on top
of UDP. QUIC aims to provide a flexible set of features that allow of UDP. QUIC aims to provide a flexible set of features that allow
it to be a general-purpose secure transport for multiple it to be a general-purpose secure transport for multiple
applications. applications.
o Version negotiation o Version negotiation
skipping to change at page 7, line 48 skipping to change at page 7, line 50
The version number for the final version of this specification The version number for the final version of this specification
(0x00000001), is reserved for the version of the protocol that is (0x00000001), is reserved for the version of the protocol that is
published as an RFC. published as an RFC.
Version numbers used to identify IETF drafts are created by adding Version numbers used to identify IETF drafts are created by adding
the draft number to 0xff000000. For example, draft-ietf-quic- the draft number to 0xff000000. For example, draft-ietf-quic-
transport-13 would be identified as 0xff00000D. transport-13 would be identified as 0xff00000D.
Implementors are encouraged to register version numbers of QUIC that Implementors are encouraged to register version numbers of QUIC that
they are using for private experimentation on the github wiki [4]. they are using for private experimentation on the GitHub wiki at
<https://github.com/quicwg/base-drafts/wiki/QUIC-Versions>.
4. Packet Types and Formats 4. Packet Types and Formats
We first describe QUIC's packet types and their formats, since some We first describe QUIC's packet types and their formats, since some
are referenced in subsequent mechanisms. are referenced in subsequent mechanisms.
All numeric values are encoded in network byte order (that is, big- All numeric values are encoded in network byte order (that is, big-
endian) and all field sizes are in bits. When discussing individual endian) and all field sizes are in bits. When discussing individual
bits of fields, the least significant bit is referred to as bit 0. bits of fields, the least significant bit is referred to as bit 0.
Hexadecimal notation is used for describing the value of fields. Hexadecimal notation is used for describing the value of fields.
skipping to change at page 8, line 38 skipping to change at page 8, line 38
| Version (32) | | Version (32) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|DCIL(4)|SCIL(4)| |DCIL(4)|SCIL(4)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Connection ID (0/32..144) ... | Destination Connection ID (0/32..144) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Connection ID (0/32..144) ... | Source Connection ID (0/32..144) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length (i) ... | Payload Length (i) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packet Number (32) | | Packet Number (8/16/32) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload (*) ... | Payload (*) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Long Header Format Figure 1: Long Header Format
Long headers are used for packets that are sent prior to the Long headers are used for packets that are sent prior to the
completion of version negotiation and establishment of 1-RTT keys. completion of version negotiation and establishment of 1-RTT keys.
Once both conditions are met, a sender switches to sending packets Once both conditions are met, a sender switches to sending packets
using the short header (Section 4.2). The long form allows for using the short header (Section 4.2). The long form allows for
skipping to change at page 9, line 41 skipping to change at page 9, line 41
field in more detail. field in more detail.
Source Connection ID: The Source Connection ID field follows the Source Connection ID: The Source Connection ID field follows the
Destination Connection ID and is either 0 octets in length or Destination Connection ID and is either 0 octets in length or
between 4 and 18 octets. Section 4.7 describes the use of this between 4 and 18 octets. Section 4.7 describes the use of this
field in more detail. field in more detail.
Payload Length: The length of the Payload field in octets, encoded Payload Length: The length of the Payload field in octets, encoded
as a variable-length integer (Section 7.1). as a variable-length integer (Section 7.1).
Packet Number: The Packet Number is a 32-bit field that follows the Packet Number: The packet number field is 1, 2, or 4 octets long.
two connection IDs. Section 4.8 describes the use of packet The packet number has confidentiality protection separate from
numbers. packet protection, as described in Section 5.6 of [QUIC-TLS]. The
length of the packet number field is encoded in the plaintext
packet number. See Section 4.8 for details.
Payload: The payload of the packet. Payload: The payload of the packet.
The following packet types are defined: The following packet types are defined:
+------+-----------------+---------------+ +------+-----------------+---------------+
| Type | Name | Section | | Type | Name | Section |
+------+-----------------+---------------+ +------+-----------------+---------------+
| 0x7F | Initial | Section 4.4.1 | | 0x7F | Initial | Section 4.4.1 |
| | | | | | | |
skipping to change at page 10, line 30 skipping to change at page 10, line 30
source connection IDs, and version fields of a long header packet are source connection IDs, and version fields of a long header packet are
version-independent. The packet number and values for packet types version-independent. The packet number and values for packet types
defined in Table 1 are version-specific. See [QUIC-INVARIANTS] for defined in Table 1 are version-specific. See [QUIC-INVARIANTS] for
details on how packets from different versions of QUIC are details on how packets from different versions of QUIC are
interpreted. interpreted.
The interpretation of the fields and the payload are specific to a The interpretation of the fields and the payload are specific to a
version and packet type. Type-specific semantics for this version version and packet type. Type-specific semantics for this version
are described in the following sections. are described in the following sections.
End of the Payload field (which is also the end of the long header The end of the Payload field (which is also the end of the long
packet) is determined by the value of the Payload Length field. header packet) is determined by the value of the Payload Length
Senders can coalesce multiple long header packets into one UDP field. Senders can sometimes coalesce multiple packets into one UDP
datagram. See Section 4.6 for more details. datagram. See Section 4.6 for more details.
4.2. Short Header 4.2. Short Header
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|0|K|1|1|0|R|T T| |0|K|1|1|0|R R R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Connection ID (0..144) ... | Destination Connection ID (0..144) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packet Number (8/16/32) ... | Packet Number (8/16/32) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protected Payload (*) ... | Protected Payload (*) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Short Header Format Figure 2: Short Header Format
skipping to change at page 11, line 34 skipping to change at page 11, line 34
definitions changed before this draft goes to the IESG.]] definitions changed before this draft goes to the IESG.]]
Google QUIC Demultipexing Bit: The fifth bit (0x8) of octet 0 is set Google QUIC Demultipexing Bit: The fifth bit (0x8) of octet 0 is set
to 0. This allows implementations of Google QUIC to distinguish to 0. This allows implementations of Google QUIC to distinguish
Google QUIC packets from short header packets sent by a client Google QUIC packets from short header packets sent by a client
because Google QUIC servers expect the connection ID to always be because Google QUIC servers expect the connection ID to always be
present. The special interpretation of this bit SHOULD be removed present. The special interpretation of this bit SHOULD be removed
from this specification when Google QUIC has finished from this specification when Google QUIC has finished
transitioning to the new header format. transitioning to the new header format.
Reserved: The sixth bit (0x4) of octet 0 is reserved for Reserved: The sixth, seventh, and eighth bits (0x7) of octet 0 are
experimentation. reserved for experimentation.
Short Packet Type: The remaining 2 bits of octet 0 include one of 4
packet types. Table 2 lists the types that are defined for short
packets.
Destination Connection ID: The Destination Connection ID is a Destination Connection ID: The Destination Connection ID is a
connection ID that is chosen by the intended recipient of the connection ID that is chosen by the intended recipient of the
packet. See Section 4.7 for more details. packet. See Section 4.7 for more details.
Packet Number: The length of the packet number field depends on the Packet Number: The packet number field is 1, 2, or 4 octets long.
packet type. This field can be 1, 2 or 4 octets long depending on The packet number has confidentiality protection separate from
the short packet type. packet protection, as described in Section 5.6 of [QUIC-TLS]. The
length of the packet number field is encoded in the plaintext
packet number. See Section 4.8 for details.
Protected Payload: Packets with a short header always include a Protected Payload: Packets with a short header always include a
1-RTT protected payload. 1-RTT protected payload.
The packet type in a short header currently determines only the size The packet type in a short header currently determines only the size
of the packet number field. Additional types can be used to signal of the packet number field. Additional types can be used to signal
the presence of other fields. the presence of other fields.
+------+--------------------+
| Type | Packet Number Size |
+------+--------------------+
| 0x0 | 1 octet |
| | |
| 0x1 | 2 octets |
| | |
| 0x2 | 4 octets |
+------+--------------------+
Table 2: Short Header Packet Types
The header form and connection ID field of a short header packet are The header form and connection ID field of a short header packet are
version-independent. The remaining fields are specific to the version-independent. The remaining fields are specific to the
selected QUIC version. See [QUIC-INVARIANTS] for details on how selected QUIC version. See [QUIC-INVARIANTS] for details on how
packets from different versions of QUIC are interpreted. packets from different versions of QUIC are interpreted.
4.3. Version Negotiation Packet 4.3. Version Negotiation Packet
A Version Negotiation packet is inherently not version-specific, and A Version Negotiation packet is inherently not version-specific, and
does not use the long packet header (see Section 4.1. Upon receipt does not use the long packet header (see Section 4.1. Upon receipt
by a client, it will appear to be a packet using the long header, but by a client, it will appear to be a packet using the long header, but
skipping to change at page 14, line 38 skipping to change at page 14, line 7
The Initial packet uses long headers with a type value of 0x7F. It The Initial packet uses long headers with a type value of 0x7F. It
carries the first cryptographic handshake message sent by the client. carries the first cryptographic handshake message sent by the client.
If the client has not previously received a Retry packet from the If the client has not previously received a Retry packet from the
server, it populates the Destination Connection ID field with a server, it populates the Destination Connection ID field with a
randomly selected value. This MUST be at least 8 octets in length. randomly selected value. This MUST be at least 8 octets in length.
Until a packet is received from the server, the client MUST use the Until a packet is received from the server, the client MUST use the
same random value unless it also changes the Source Connection ID same random value unless it also changes the Source Connection ID
(which effectively starts a new connection attempt). The randomized (which effectively starts a new connection attempt). The randomized
Destination Connection ID is used to determine packet protection Destination Connection ID is used to determine packet protection
keys, but is not included in server packets. keys.
If the client received a Retry packet and is sending a second Initial If the client received a Retry packet and is sending a second Initial
packet, then it sets the Destination Connection ID to the value from packet, then it sets the Destination Connection ID to the value from
the Source Connection ID in the Retry packet. Changing Destination the Source Connection ID in the Retry packet. Changing Destination
Connection ID also results in a change to the keys used to protect Connection ID also results in a change to the keys used to protect
the Initial packet. the Initial packet.
The client populates the Source Connection ID field with a value of The client populates the Source Connection ID field with a value of
its choosing and sets the low bits of the ConnID Len field to match. its choosing and sets the SCIL field to match.
The first Initial packet that is sent by a client contains a The first Initial packet that is sent by a client contains a packet
randomized packet number. All subsequent packets contain a packet number of 0. All subsequent packets contain a packet number that is
number that is incremented by one, see (Section 4.8). incremented by at least one, see (Section 4.8).
The payload of an Initial packet conveys a STREAM frame (or frames) The payload of an Initial packet conveys a STREAM frame (or frames)
for stream 0 containing a cryptographic handshake message. The for stream 0 containing a cryptographic handshake message. The
stream in this packet always starts at an offset of 0 (see stream in this packet always starts at an offset of 0 (see
Section 6.5) and the complete cryptographic handshake message MUST Section 6.5) and the complete cryptographic handshake message MUST
fit in a single packet (see Section 6.3). fit in a single packet (see Section 6.3).
The payload of a UDP datagram carrying the Initial packet MUST be The payload of a UDP datagram carrying the Initial packet MUST be
expanded to at least 1200 octets (see Section 8), by adding PADDING expanded to at least 1200 octets (see Section 8), by adding PADDING
frames to the Initial packet and/or by combining the Initial packet frames to the Initial packet and/or by combining the Initial packet
skipping to change at page 15, line 37 skipping to change at page 15, line 9
Section 6.5). Section 6.5).
The server populates the Destination Connection ID with the The server populates the Destination Connection ID with the
connection ID that the client included in the Source Connection ID of connection ID that the client included in the Source Connection ID of
the Initial packet. This might be a zero-length value. the Initial packet. This might be a zero-length value.
The server includes a connection ID of its choice in the Source The server includes a connection ID of its choice in the Source
Connection ID field. The client MUST use this connection ID in the Connection ID field. The client MUST use this connection ID in the
Destination Connection ID of subsequent packets that it sends. Destination Connection ID of subsequent packets that it sends.
The packet number field echoes the packet number field from the The Packet Number field of a Retry packet MUST be set to 0. This
triggering client packet. value is subsequently protected as normal. [[Editor's Note: This
isn't ideal, because it creates a "cheat" where the client assumes a
value. That's a problem, so I'm tempted to suggest that this include
any value less than 2^30 so that normal processing works - and can be
properly exercised.]]
A Retry packet is never explicitly acknowledged in an ACK frame by a A Retry packet is never explicitly acknowledged in an ACK frame by a
client. Receiving another Initial packet implicitly acknowledges a client. Receiving another Initial packet implicitly acknowledges a
Retry packet. Retry packet.
After receiving a Retry packet, the client uses a new Initial packet After receiving a Retry packet, the client uses a new Initial packet
containing the next cryptographic handshake message. The client containing the next cryptographic handshake message. The client
retains the state of its cryptographic handshake, but discards all retains the state of its cryptographic handshake, but discards all
transport state. The Initial packet that is generated in response to transport state. The Initial packet that is generated in response to
a Retry packet includes STREAM frames on stream 0 that start again at a Retry packet includes STREAM frames on stream 0 that start again at
skipping to change at page 16, line 4 skipping to change at page 15, line 29
After receiving a Retry packet, the client uses a new Initial packet After receiving a Retry packet, the client uses a new Initial packet
containing the next cryptographic handshake message. The client containing the next cryptographic handshake message. The client
retains the state of its cryptographic handshake, but discards all retains the state of its cryptographic handshake, but discards all
transport state. The Initial packet that is generated in response to transport state. The Initial packet that is generated in response to
a Retry packet includes STREAM frames on stream 0 that start again at a Retry packet includes STREAM frames on stream 0 that start again at
an offset of 0. an offset of 0.
Continuing the cryptographic handshake is necessary to ensure that an Continuing the cryptographic handshake is necessary to ensure that an
attacker cannot force a downgrade of any cryptographic parameters. attacker cannot force a downgrade of any cryptographic parameters.
In addition to continuing the cryptographic handshake, the client In addition to continuing the cryptographic handshake, the client
MUST remember the results of any version negotiation that occurred MUST remember the results of any version negotiation that occurred
(see Section 6.2). The client MAY also retain any observed RTT or (see Section 6.2). The client MAY also retain any observed RTT or
congestion state that it has accumulated for the flow, but other congestion state that it has accumulated for the flow, but other
transport state MUST be discarded. transport state MUST be discarded.
The payload of the Retry packet contains at least two frames. It The payload of the Retry packet contains at least two frames. It
MUST include a STREAM frame on stream 0 with offset 0 containing the MUST include a STREAM frame on stream 0 with offset 0 containing the
server's cryptographic stateless retry material. It MUST also server's cryptographic stateless retry material. It MUST also
include an ACK frame to acknowledge the client's Initial packet. It include an ACK frame to acknowledge the client's Initial packet. It
MAY additionally include PADDING frames. The next STREAM frame sent MAY additionally include PADDING frames. The next STREAM frame sent
by the server will also start at stream offset 0. by the server will also start at stream offset 0.
4.4.3. Handshake Packet 4.4.3. Handshake Packet
A Handshake packet uses long headers with a type value of 0x7D. It A Handshake packet uses long headers with a type value of 0x7D. It
is used to carry acknowledgments and cryptographic handshake messages is used to carry acknowledgments and cryptographic handshake messages
from the server and client. from the server and client.
A server sends its cryptographic handshake in one or more Handshake
packets in response to an Initial packet if it does not send a Retry
packet. Once a client has received a Handshake packet from a server,
it uses Handshake packets to send subsequent cryptographic handshake
messages and acknowledgments to the server.
The Destination Connection ID field in a Handshake packet contains a The Destination Connection ID field in a Handshake packet contains a
connection ID that is chosen by the recipient of the packet; the connection ID that is chosen by the recipient of the packet; the
Source Connection ID includes the connection ID that the sender of Source Connection ID includes the connection ID that the sender of
the packet wishes to use (see Section 4.7). the packet wishes to use (see Section 4.7).
The first Handshake packet sent by a server contains a randomized The first Handshake packet sent by a server contains a packet number
packet number. This value is increased for each subsequent packet of 0. Packet numbers are incremented normally for other Handshake
sent by the server as described in Section 4.8. The client packets.
increments the packet number from its previous packet by one for each
Handshake packet that it sends (which might be an Initial, 0-RTT
Protected, or Handshake packet).
Servers MUST NOT send more than three Handshake packets without Servers MUST NOT send more than three Handshake packets without
receiving a packet from a verified source address. Source addresses receiving a packet from a verified source address. Source addresses
can be verified through an address validation token, receipt of the can be verified through an address validation token, receipt of the
final cryptographic message from the client, or by receiving a valid final cryptographic message from the client, or by receiving a valid
PATH_RESPONSE frame from the client. PATH_RESPONSE frame from the client.
If the server expects to generate more than three Handshake packets If the server expects to generate more than three Handshake packets
in response to an Initial packet, it SHOULD include a PATH_CHALLENGE in response to an Initial packet, it SHOULD include a PATH_CHALLENGE
frame in each Handshake packet that it sends. After receiving at frame in each Handshake packet that it sends. After receiving at
skipping to change at page 17, line 9 skipping to change at page 16, line 36
server, but could involve additional computational effort depending server, but could involve additional computational effort depending
on implementation choices. on implementation choices.
The payload of this packet contains STREAM frames and could contain The payload of this packet contains STREAM frames and could contain
PADDING, ACK, PATH_CHALLENGE, or PATH_RESPONSE frames. Handshake PADDING, ACK, PATH_CHALLENGE, or PATH_RESPONSE frames. Handshake
packets MAY contain CONNECTION_CLOSE frames if the handshake is packets MAY contain CONNECTION_CLOSE frames if the handshake is
unsuccessful. unsuccessful.
4.5. Protected Packets 4.5. Protected Packets
Packets that are protected with 0-RTT keys are sent with long All QUIC packets are protected. Packets that are protected with the
headers; all packets protected with 1-RTT keys are sent with short static handshake keys or the 0-RTT keys are sent with long headers;
headers. The different packet types explicitly indicate the all packets protected with 1-RTT keys are sent with short headers.
encryption level and therefore the keys that are used to remove The different packet types explicitly indicate the encryption level
packet protection. and therefore the keys that are used to remove packet protection.
Packets protected with 0-RTT keys use a type value of 0x7C. The Packets protected with 0-RTT keys use a type value of 0x7C. The
connection ID fields for a 0-RTT packet MUST match the values used in connection ID fields for a 0-RTT packet MUST match the values used in
the Initial packet (Section 4.4.1). the Initial packet (Section 4.4.1).
The client can send 0-RTT packets after receiving a Handshake packet The client can send 0-RTT packets after receiving a Handshake packet
(Section 4.4.3), if that packet does not complete the handshake. (Section 4.4.3), if that packet does not complete the handshake.
Even if the client receives a different connection ID in the Even if the client receives a different connection ID in the
Handshake packet, it MUST continue to use the same Destination Handshake packet, it MUST continue to use the same Destination
Connection ID for 0-RTT packets, see Section 4.7. Connection ID for 0-RTT packets, see Section 4.7.
The version field for protected packets is the current QUIC version. The version field for protected packets is the current QUIC version.
The packet number field contains a packet number, which increases The packet number field contains a packet number, which has
with each packet sent, see Section 4.8 for details. additional confidentiality protection that is applied after packet
protection is applied (see [QUIC-TLS] for details). The underlying
packet number increases with each packet sent, see Section 4.8 for
details.
The payload is protected using authenticated encryption. [QUIC-TLS] The payload is protected using authenticated encryption. [QUIC-TLS]
describes packet protection in detail. After decryption, the describes packet protection in detail. After decryption, the
plaintext consists of a sequence of frames, as described in plaintext consists of a sequence of frames, as described in
Section 5. Section 5.
4.6. Coaslescing Packets 4.6. Coalescing Packets
A sender can coalesce multiple QUIC packets (typically a A sender can coalesce multiple QUIC packets (typically a
Cryptographic Handshake packet and a Protected packet) into one UDP Cryptographic Handshake packet and a Protected packet) into one UDP
datagram. This can reduce the number of UDP datagrams needed to send datagram. This can reduce the number of UDP datagrams needed to send
application data during the handshake and immediately afterwards. A application data during the handshake and immediately afterwards. A
packet with a short header does not include a length, so it has to be packet with a short header does not include a length, so it has to be
the last packet included in a UDP datagram. the last packet included in a UDP datagram.
The sender MUST NOT coalesce QUIC packets belonging to different QUIC The sender MUST NOT coalesce QUIC packets belonging to different QUIC
connections into a single UDP datagram. connections into a single UDP datagram.
skipping to change at page 19, line 19 skipping to change at page 18, line 44
The connection ID can change over the lifetime of a connection, The connection ID can change over the lifetime of a connection,
especially in response to connection migration (Section 6.8). especially in response to connection migration (Section 6.8).
NEW_CONNECTION_ID frames (Section 7.13) are used to provide new NEW_CONNECTION_ID frames (Section 7.13) are used to provide new
connection ID values. connection ID values.
4.8. Packet Numbers 4.8. Packet Numbers
The packet number is an integer in the range 0 to 2^62-1. The value The packet number is an integer in the range 0 to 2^62-1. The value
is used in determining the cryptographic nonce for packet encryption. is used in determining the cryptographic nonce for packet encryption.
Each endpoint maintains a separate packet number for sending and Each endpoint maintains a separate packet number for sending and
receiving. The packet number for sending MUST increase by at least receiving. The packet number for sending MUST start at zero for the
one after sending any packet, unless otherwise specified (see first packet sent and MUST increase by at least one after sending a
Section 4.8.1). packet.
A QUIC endpoint MUST NOT reuse a packet number within the same A QUIC endpoint MUST NOT reuse a packet number within the same
connection (that is, under the same cryptographic keys). If the connection (that is, under the same cryptographic keys). If the
packet number for sending reaches 2^62 - 1, the sender MUST close the packet number for sending reaches 2^62 - 1, the sender MUST close the
connection without sending a CONNECTION_CLOSE frame or any further connection without sending a CONNECTION_CLOSE frame or any further
packets; a server MAY send a Stateless Reset (Section 6.9.4) in packets; a server MAY send a Stateless Reset (Section 6.10.4) in
response to further packets that it receives. response to further packets that it receives.
For the packet header, the number of bits required to represent the In the QUIC long and short packet headers, the number of bits
packet number are reduced by including only the least significant required to represent the packet number are reduced by including only
bits of the packet number. The actual packet number for each packet a variable number of the least significant bits of the packet number.
is reconstructed at the receiver based on the largest packet number One or two of the most significant bits of the first octet determine
received on a successfully authenticated packet. how many bits of the packet number are provided, as shown in Table 2.
A packet number is decoded by finding the packet number value that is +---------------------+----------------+--------------+
closest to the next expected packet. The next expected packet is the | First octet pattern | Encoded Length | Bits Present |
highest received packet number plus one. For example, if the highest +---------------------+----------------+--------------+
| 0b0xxxxxxx | 1 octet | 7 |
| | | |
| 0b10xxxxxx | 2 | 14 |
| | | |
| 0b11xxxxxx | 4 | 30 |
+---------------------+----------------+--------------+
Table 2: Packet Number Encodings for Packet Headers
Note that these encodings are similar to those in Section 7.1, but
use different values.
The encoded packet number is protected as described in Section 5.6
[QUIC-TLS]. Protection of the packet number is removed prior to
recovering the full packet number. The full packet number is
reconstructed at the receiver based on the number of significant bits
present, the content of those bits, and the largest packet number
received on a successfully authenticated packet. Recovering the full
packet number is necessary to successfully remove packet protection.
Once packet number protection is removed, the packet number is
decoded by finding the packet number value that is closest to the
next expected packet. The next expected packet is the highest
received packet number plus one. For example, if the highest
successfully authenticated packet had a packet number of 0xaa82f30e, successfully authenticated packet had a packet number of 0xaa82f30e,
then a packet containing a 16-bit value of 0x1f94 will be decoded as then a packet containing a 14-bit value of 0x1f94 will be decoded as
0xaa831f94. 0xaa831f94.
The sender MUST use a packet number size able to represent more than The sender MUST use a packet number size able to represent more than
twice as large a range than the difference between the largest twice as large a range than the difference between the largest
acknowledged packet and packet number being sent. A peer receiving acknowledged packet and packet number being sent. A peer receiving
the packet will then correctly decode the packet number, unless the the packet will then correctly decode the packet number, unless the
packet is delayed in transit such that it arrives after many higher- packet is delayed in transit such that it arrives after many higher-
numbered packets have been received. An endpoint SHOULD use a large numbered packets have been received. An endpoint SHOULD use a large
enough packet number encoding to allow the packet number to be enough packet number encoding to allow the packet number to be
recovered even if the packet arrives after packets that are sent recovered even if the packet arrives after packets that are sent
afterwards. afterwards.
As a result, the size of the packet number encoding is at least one As a result, the size of the packet number encoding is at least one
more than the base 2 logarithm of the number of contiguous more than the base 2 logarithm of the number of contiguous
unacknowledged packet numbers, including the new packet. unacknowledged packet numbers, including the new packet.
For example, if an endpoint has received an acknowledgment for packet For example, if an endpoint has received an acknowledgment for packet
0x6afa2f, sending a packet with a number of 0x6b4264 requires a 0x6afa2f, sending a packet with a number of 0x6b2d79 requires a
16-bit or larger packet number encoding; whereas a 32-bit packet packet number encoding with 14 bits or more; whereas the 30-bit
number is needed to send a packet with a number of 0x6bc107. packet number encoding is needed to send a packet with a number of
0x6bc107.
A Version Negotiation packet (Section 4.3) does not include a packet A Version Negotiation packet (Section 4.3) does not include a packet
number. The Retry packet (Section 4.4.2) has special rules for number. The Retry packet (Section 4.4.2) has special rules for
populating the packet number field. populating the packet number field.
4.8.1. Initial Packet Number
The initial value for packet number MUST be selected randomly from a
range between 0 and 2^32 - 1025 (inclusive). This value is selected
so that Initial and Handshake packets exercise as many possible
values for the Packet Number field as possible.
Limiting the range allows both for loss of packets and for any
stateless exchanges. Packet numbers are incremented for subsequent
packets, but packet loss and stateless handling can both mean that
the first packet sent by an endpoint isn't necessarily the first
packet received by its peer. The first packet received by a peer
cannot be 2^32 or greater or the recipient will incorrectly assume a
packet number that is 2^32 values lower and discard the packet.
Use of a secure random number generator [RFC4086] is not necessary
for generating the initial packet number, nor is it necessary that
the value be uniformly distributed.
5. Frames and Frame Types 5. Frames and Frame Types
The payload of all packets, after removing packet protection, The payload of all packets, after removing packet protection,
consists of a sequence of frames, as shown in Figure 4. Version consists of a sequence of frames, as shown in Figure 4. Version
Negotiation and Stateless Reset do not contain frames. Negotiation and Stateless Reset do not contain frames.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Frame 1 (*) ... | Frame 1 (*) ...
skipping to change at page 23, line 5 skipping to change at page 23, line 5
6. Life of a Connection 6. Life of a Connection
A QUIC connection is a single conversation between two QUIC A QUIC connection is a single conversation between two QUIC
endpoints. QUIC's connection establishment intertwines version endpoints. QUIC's connection establishment intertwines version
negotiation with the cryptographic and transport handshakes to reduce negotiation with the cryptographic and transport handshakes to reduce
connection establishment latency, as described in Section 6.3. Once connection establishment latency, as described in Section 6.3. Once
established, a connection may migrate to a different IP or port at established, a connection may migrate to a different IP or port at
either endpoint, due to NAT rebinding or mobility, as described in either endpoint, due to NAT rebinding or mobility, as described in
Section 6.8. Finally a connection may be terminated by either Section 6.8. Finally a connection may be terminated by either
endpoint, as described in Section 6.9. endpoint, as described in Section 6.10.
6.1. Matching Packets to Connections 6.1. Matching Packets to Connections
Incoming packets are classified on receipt. Packets can either be Incoming packets are classified on receipt. Packets can either be
associated with an existing connection, or - for servers - associated with an existing connection, or - for servers -
potentially create a new connection. potentially create a new connection.
Hosts try to associate a packet with an existing connection. If the Hosts try to associate a packet with an existing connection. If the
packet has a Destination Connection ID corresponding to an existing packet has a Destination Connection ID corresponding to an existing
connection, QUIC processes that packet accordingly. Note that a connection, QUIC processes that packet accordingly. Note that a
skipping to change at page 24, line 32 skipping to change at page 24, line 32
send a Handshake packet containing a CONNECTION_CLOSE frame with send a Handshake packet containing a CONNECTION_CLOSE frame with
error code SERVER_BUSY. error code SERVER_BUSY.
If the packet is a 0-RTT packet, the server MAY buffer a limited If the packet is a 0-RTT packet, the server MAY buffer a limited
number of these packets in anticipation of a late-arriving Initial number of these packets in anticipation of a late-arriving Initial
Packet. Clients are forbidden from sending Handshake packets prior Packet. Clients are forbidden from sending Handshake packets prior
to receiving a server response, so servers SHOULD ignore any such to receiving a server response, so servers SHOULD ignore any such
packets. packets.
Servers MUST drop incoming packets under all other circumstances. Servers MUST drop incoming packets under all other circumstances.
They SHOULD send a Stateless Reset (Section 6.9.4) if a connection ID They SHOULD send a Stateless Reset (Section 6.10.4) if a connection
is present in the header. ID is present in the header.
6.2. Version Negotiation 6.2. Version Negotiation
Version negotiation ensures that client and server agree to a QUIC Version negotiation ensures that client and server agree to a QUIC
version that is mutually supported. A server sends a Version version that is mutually supported. A server sends a Version
Negotiation packet in response to each packet that might initiate a Negotiation packet in response to each packet that might initiate a
new connection, see Section 6.1 for details. new connection, see Section 6.1 for details.
The size of the first packet sent by a client will determine whether The size of the first packet sent by a client will determine whether
a server sends a Version Negotiation packet. Clients that support a server sends a Version Negotiation packet. Clients that support
skipping to change at page 28, line 10 skipping to change at page 28, line 10
The format of the transport parameters is the TransportParameters The format of the transport parameters is the TransportParameters
struct from Figure 6. This is described using the presentation struct from Figure 6. This is described using the presentation
language from Section 3 of [I-D.ietf-tls-tls13]. language from Section 3 of [I-D.ietf-tls-tls13].
uint32 QuicVersion; uint32 QuicVersion;
enum { enum {
initial_max_stream_data(0), initial_max_stream_data(0),
initial_max_data(1), initial_max_data(1),
initial_max_stream_id_bidi(2), initial_max_bidi_streams(2),
idle_timeout(3), idle_timeout(3),
preferred_address(4),
max_packet_size(5), max_packet_size(5),
stateless_reset_token(6), stateless_reset_token(6),
ack_delay_exponent(7), ack_delay_exponent(7),
initial_max_stream_id_uni(8), initial_max_uni_streams(8),
(65535) (65535)
} TransportParameterId; } TransportParameterId;
struct { struct {
TransportParameterId parameter; TransportParameterId parameter;
opaque value<0..2^16-1>; opaque value<0..2^16-1>;
} TransportParameter; } TransportParameter;
struct { struct {
select (Handshake.msg_type) { select (Handshake.msg_type) {
case client_hello: case client_hello:
QuicVersion initial_version; QuicVersion initial_version;
case encrypted_extensions: case encrypted_extensions:
QuicVersion negotiated_version; QuicVersion negotiated_version;
QuicVersion supported_versions<4..2^8-4>; QuicVersion supported_versions<4..2^8-4>;
}; };
TransportParameter parameters<22..2^16-1>; TransportParameter parameters<22..2^16-1>;
} TransportParameters; } TransportParameters;
struct {
enum { IPv4(4), IPv6(6), (15) } ipVersion;
opaque ipAddress<4..2^8-1>;
uint16 port;
opaque connectionId<0..18>;
opaque statelessResetToken[16];
} PreferredAddress;
Figure 6: Definition of TransportParameters Figure 6: Definition of TransportParameters
The "extension_data" field of the quic_transport_parameters extension The "extension_data" field of the quic_transport_parameters extension
defined in [QUIC-TLS] contains a TransportParameters value. TLS defined in [QUIC-TLS] contains a TransportParameters value. TLS
encoding rules are therefore used to encode the transport parameters. encoding rules are therefore used to encode the transport parameters.
QUIC encodes transport parameters into a sequence of octets, which QUIC encodes transport parameters into a sequence of octets, which
are then included in the cryptographic handshake. Once the handshake are then included in the cryptographic handshake. Once the handshake
completes, the transport parameters declared by the peer are completes, the transport parameters declared by the peer are
available. Each endpoint validates the value provided by its peer. available. Each endpoint validates the value provided by its peer.
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unsigned 32-bit integer in units of octets. This is equivalent to unsigned 32-bit integer in units of octets. This is equivalent to
sending a MAX_DATA (Section 7.6) for the connection immediately sending a MAX_DATA (Section 7.6) for the connection immediately
after completing the handshake. after completing the handshake.
idle_timeout (0x0003): The idle timeout is a value in seconds that idle_timeout (0x0003): The idle timeout is a value in seconds that
is encoded as an unsigned 16-bit integer. The maximum value is is encoded as an unsigned 16-bit integer. The maximum value is
600 seconds (10 minutes). 600 seconds (10 minutes).
An endpoint MAY use the following transport parameters: An endpoint MAY use the following transport parameters:
initial_max_streams_bidi (0x0002): The initial maximum bidirectional initial_max_bidi_streams (0x0002): The initial maximum bidirectional
streams parameter contains the initial maximum number of streams parameter contains the initial maximum number of
application-owned bidirectional streams the peer may initiate, application-owned bidirectional streams the peer may initiate,
encoded as an unsigned 16-bit integer. If this parameter is encoded as an unsigned 16-bit integer. If this parameter is
absent or zero, application-owned bidirectional streams cannot be absent or zero, application-owned bidirectional streams cannot be
created until a MAX_STREAM_ID frame is sent. Note that a value of created until a MAX_STREAM_ID frame is sent. Note that a value of
0 does not prevent the cryptographic handshake stream (that is, 0 does not prevent the cryptographic handshake stream (that is,
stream 0) from being used. Setting this parameter is equivalent stream 0) from being used. Setting this parameter is equivalent
to sending a MAX_STREAM_ID (Section 7.8) immediately after to sending a MAX_STREAM_ID (Section 7.8) immediately after
completing the handshake containing the corresponding Stream ID. completing the handshake containing the corresponding Stream ID.
For example, a value of 0x05 would be equivalent to receiving a For example, a value of 0x05 would be equivalent to receiving a
MAX_STREAM_ID containing 20 when received by a client or 17 when MAX_STREAM_ID containing 20 when received by a client or 17 when
received by a server. received by a server.
initial_max_stream_id_uni (0x0008): The initial maximum initial_max_uni_streams (0x0008): The initial maximum unidirectional
unidirectional streams parameter contains the initial maximum streams parameter contains the initial maximum number of
number of application-owned unidirectional streams the peer may application-owned unidirectional streams the peer may initiate,
initiate, encoded as an unsigned 16-bit integer. If this encoded as an unsigned 16-bit integer. If this parameter is
parameter is absent or zero, unidirectional streams cannot be absent or zero, unidirectional streams cannot be created until a
created until a MAX_STREAM_ID frame is sent. Setting this MAX_STREAM_ID frame is sent. Setting this parameter is equivalent
parameter is equivalent to sending a MAX_STREAM_ID (Section 7.8) to sending a MAX_STREAM_ID (Section 7.8) immediately after
immediately after completing the handshake containing the completing the handshake containing the corresponding Stream ID.
corresponding Stream ID. For example, a value of 0x05 would be For example, a value of 0x05 would be equivalent to receiving a
equivalent to receiving a MAX_STREAM_ID containing 18 when MAX_STREAM_ID containing 18 when received by a client or 19 when
received by a client or 19 when received by a server. received by a server.
max_packet_size (0x0005): The maximum packet size parameter places a max_packet_size (0x0005): The maximum packet size parameter places a
limit on the size of packets that the endpoint is willing to limit on the size of packets that the endpoint is willing to
receive, encoded as an unsigned 16-bit integer. This indicates receive, encoded as an unsigned 16-bit integer. This indicates
that packets larger than this limit will be dropped. The default that packets larger than this limit will be dropped. The default
for this parameter is the maximum permitted UDP payload of 65527. for this parameter is the maximum permitted UDP payload of 65527.
Values below 1200 are invalid. This limit only applies to Values below 1200 are invalid. This limit only applies to
protected packets (Section 4.5). protected packets (Section 4.5).
ack_delay_exponent (0x0007): An 8-bit unsigned integer value ack_delay_exponent (0x0007): An 8-bit unsigned integer value
indicating an exponent used to decode the ACK Delay field in the indicating an exponent used to decode the ACK Delay field in the
ACK frame, see Section 7.15. If this value is absent, a default ACK frame, see Section 7.15. If this value is absent, a default
value of 3 is assumed (indicating a multiplier of 8). The default value of 3 is assumed (indicating a multiplier of 8). The default
value is also used for ACK frames that are sent in Initial, value is also used for ACK frames that are sent in Initial,
Handshake, and Retry packets. Values above 20 are invalid. Handshake, and Retry packets. Values above 20 are invalid.
A server MAY include the following transport parameters: A server MAY include the following transport parameters:
stateless_reset_token (0x0006): The Stateless Reset Token is used in stateless_reset_token (0x0006): The Stateless Reset Token is used in
verifying a stateless reset, see Section 6.9.4. This parameter is verifying a stateless reset, see Section 6.10.4. This parameter
a sequence of 16 octets. is a sequence of 16 octets.
A client MUST NOT include a stateless reset token. A server MUST preferred_address (0x0004): The server's Preferred Address is used
treat receipt of a stateless_reset_token transport parameter as a to effect a change in server address at the end of the handshake,
connection error of type TRANSPORT_PARAMETER_ERROR. as described in Section 6.9.
A client MUST NOT include a stateless reset token or a preferred
address. A server MUST treat receipt of either transport parameter
as a connection error of type TRANSPORT_PARAMETER_ERROR.
6.4.2. Values of Transport Parameters for 0-RTT 6.4.2. Values of Transport Parameters for 0-RTT
A client that attempts to send 0-RTT data MUST remember the transport A client that attempts to send 0-RTT data MUST remember the transport
parameters used by the server. The transport parameters that the parameters used by the server. The transport parameters that the
server advertises during connection establishment apply to all server advertises during connection establishment apply to all
connections that are resumed using the keying material established connections that are resumed using the keying material established
during that handshake. Remembered transport parameters apply to the during that handshake. Remembered transport parameters apply to the
new connection until the handshake completes and new transport new connection until the handshake completes and new transport
parameters from the server can be provided. parameters from the server can be provided.
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recover the information when accepting 0-RTT data. A server uses the recover the information when accepting 0-RTT data. A server uses the
transport parameters in determining whether to accept 0-RTT data. transport parameters in determining whether to accept 0-RTT data.
A server MAY accept 0-RTT and subsequently provide different values A server MAY accept 0-RTT and subsequently provide different values
for transport parameters for use in the new connection. If 0-RTT for transport parameters for use in the new connection. If 0-RTT
data is accepted by the server, the server MUST NOT reduce any limits data is accepted by the server, the server MUST NOT reduce any limits
or alter any values that might be violated by the client with its or alter any values that might be violated by the client with its
0-RTT data. In particular, a server that accepts 0-RTT data MUST NOT 0-RTT data. In particular, a server that accepts 0-RTT data MUST NOT
set values for initial_max_data or initial_max_stream_data that are set values for initial_max_data or initial_max_stream_data that are
smaller than the remembered value of those parameters. Similarly, a smaller than the remembered value of those parameters. Similarly, a
server MUST NOT reduce the value of initial_max_stream_id_bidi or server MUST NOT reduce the value of initial_max_bidi_streams or
initial_max_stream_id_uni. initial_max_uni_streams.
Omitting or setting a zero value for certain transport parameters can Omitting or setting a zero value for certain transport parameters can
result in 0-RTT data being enabled, but not usable. The following result in 0-RTT data being enabled, but not usable. The following
transport parameters SHOULD be set to non-zero values for 0-RTT: transport parameters SHOULD be set to non-zero values for 0-RTT:
initial_max_stream_id_bidi, initial_max_stream_id_uni, initial_max_bidi_streams, initial_max_uni_streams, initial_max_data,
initial_max_data, initial_max_stream_data. initial_max_stream_data.
The value of the server's previous preferred_address MUST NOT be used
when establishing a new connection; rather, the client should wait to
observe the server's new preferred_address value in the handshake.
A server MUST reject 0-RTT data or even abort a handshake if the A server MUST reject 0-RTT data or even abort a handshake if the
implied values for transport parameters cannot be supported. implied values for transport parameters cannot be supported.
6.4.3. New Transport Parameters 6.4.3. New Transport Parameters
New transport parameters can be used to negotiate new protocol New transport parameters can be used to negotiate new protocol
behavior. An endpoint MUST ignore transport parameters that it does behavior. An endpoint MUST ignore transport parameters that it does
not support. Absence of a transport parameter therefore disables any not support. Absence of a transport parameter therefore disables any
optional protocol feature that is negotiated using the parameter. optional protocol feature that is negotiated using the parameter.
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format of the version fields in transport parameters MUST either be format of the version fields in transport parameters MUST either be
identical across different QUIC versions, or be unambiguously identical across different QUIC versions, or be unambiguously
different to ensure no confusion about their interpretation. One way different to ensure no confusion about their interpretation. One way
that a new format could be introduced is to define a TLS extension that a new format could be introduced is to define a TLS extension
with a different codepoint. with a different codepoint.
6.5. Stateless Retries 6.5. Stateless Retries
A server can process an initial cryptographic handshake messages from A server can process an initial cryptographic handshake messages from
a client without committing any state. This allows a server to a client without committing any state. This allows a server to
perform address validation (Section 6.6, or to defer connection perform address validation (Section 6.6), or to defer connection
establishment costs. establishment costs.
A server that generates a response to an initial packet without A server that generates a response to an initial packet without
retaining connection state MUST use the Retry packet (Section 4.4.2). retaining connection state MUST use the Retry packet (Section 4.4.2).
This packet causes a client to reset its transport state and to This packet causes a client to reset its transport state and to
continue the connection attempt with new connection state while continue the connection attempt with new connection state while
maintaining the state of the cryptographic handshake. maintaining the state of the cryptographic handshake.
A server MUST NOT send multiple Retry packets in response to a client A server MUST NOT send multiple Retry packets in response to a client
handshake packet. Thus, any cryptographic handshake message that is handshake packet. Thus, any cryptographic handshake message that is
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PROTOCOL_VIOLATION error code. PROTOCOL_VIOLATION error code.
6.7. Path Validation 6.7. Path Validation
Path validation is used by an endpoint to verify reachability of a Path validation is used by an endpoint to verify reachability of a
peer over a specific path. That is, it tests reachability between a peer over a specific path. That is, it tests reachability between a
specific local address and a specific peer address, where an address specific local address and a specific peer address, where an address
is the two-tuple of IP address and port. Path validation tests that is the two-tuple of IP address and port. Path validation tests that
packets can be both sent to and received from a peer. packets can be both sent to and received from a peer.
Path validation is used during connection migration (see Section 6.8) Path validation is used during connection migration (see Section 6.8
by the migrating endpoint to verify reachability of a peer from a new and Section 6.9) by the migrating endpoint to verify reachability of
local address. Path validation is also used by the peer to verify a peer from a new local address. Path validation is also used by the
that the migrating endpoint is able to receive packets sent to its peer to verify that the migrating endpoint is able to receive packets
new address. That is, that the packets received from the migrating sent to the its new address. That is, that the packets received from
endpoint do not carry a spoofed source address. the migrating endpoint do not carry a spoofed source address.
Path validation can be used at any time by either endpoint. For Path validation can be used at any time by either endpoint. For
instance, an endpoint might check that a peer is still in possession instance, an endpoint might check that a peer is still in possession
of its address after a period of quiescence. of its address after a period of quiescence.
Path validation is not designed as a NAT traversal mechanism. Though Path validation is not designed as a NAT traversal mechanism. Though
the mechanism described here might be effective for the creation of the mechanism described here might be effective for the creation of
NAT bindings that support NAT traversal, the expectation is that one NAT bindings that support NAT traversal, the expectation is that one
or other peer is able to receive packets without first having sent a or other peer is able to receive packets without first having sent a
packet on that path. Effective NAT traversal needs additional packet on that path. Effective NAT traversal needs additional
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QUIC allows connections to survive changes to endpoint addresses QUIC allows connections to survive changes to endpoint addresses
(that is, IP address and/or port), such as those caused by a endpoint (that is, IP address and/or port), such as those caused by a endpoint
migrating to a new network. This section describes the process by migrating to a new network. This section describes the process by
which an endpoint migrates to a new address. which an endpoint migrates to a new address.
An endpoint MUST NOT initiate connection migration before the An endpoint MUST NOT initiate connection migration before the
handshake is finished and the endpoint has 1-RTT keys. handshake is finished and the endpoint has 1-RTT keys.
This document limits migration of connections to new client This document limits migration of connections to new client
addresses. Clients are responsible for initiating all migrations. addresses, except as described in Section 6.9. Clients are
Servers do not send non-probing packets (see Section 6.8.1) toward a responsible for initiating all migrations. Servers do not send non-
client address until it sees a non-probing packet from that address. probing packets (see Section 6.8.1) toward a client address until it
If a client receives packets from an unknown server address, the sees a non-probing packet from that address. If a client receives
client MAY discard these packets. Migrating a connection to a new packets from an unknown server address, the client MAY discard these
server address is left for future work. packets.
6.8.1. Probing a New Path 6.8.1. Probing a New Path
An endpoint MAY probe for peer reachability from a new local address An endpoint MAY probe for peer reachability from a new local address
using path validation Section 6.7 prior to migrating the connection using path validation Section 6.7 prior to migrating the connection
to the new local address. Failure of path validation simply means to the new local address. Failure of path validation simply means
that the new path is not usable for this connection. Failure to that the new path is not usable for this connection. Failure to
validate a path does not cause the connection to end unless there are validate a path does not cause the connection to end unless there are
no valid alternative paths available. no valid alternative paths available.
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a PATH_CHALLENGE is sent, which is disarmed when the corresponding a PATH_CHALLENGE is sent, which is disarmed when the corresponding
PATH_RESPONSE is received. If the alarm fires before the PATH_RESPONSE is received. If the alarm fires before the
PATH_RESPONSE is received, the endpoint might send a new PATH_RESPONSE is received, the endpoint might send a new
PATH_CHALLENGE, and restart the alarm for a longer period of time. PATH_CHALLENGE, and restart the alarm for a longer period of time.
6.8.5. Privacy Implications of Connection Migration 6.8.5. Privacy Implications of Connection Migration
Using a stable connection ID on multiple network paths allows a Using a stable connection ID on multiple network paths allows a
passive observer to correlate activity between those paths. An passive observer to correlate activity between those paths. An
endpoint that moves between networks might not wish to have their endpoint that moves between networks might not wish to have their
activity correlated by any entity other than a server. The activity correlated by any entity other than their peer. The
NEW_CONNECTION_ID message can be sent by both endpoints to provide an NEW_CONNECTION_ID message can be sent to provide an unlinkable
unlinkable connection ID for use in case a peer wishes to explicitly connection ID for use in case a peer wishes to explicitly break
break linkability between two points of network attachment. linkability between two points of network attachment.
An endpoint might need to send packets on multiple networks without
receiving any response from its peer. To ensure that the endpoint is
not linkable across each of these changes, a new connection ID and
packet number gap are needed for each network. To support this, each
endpoint sends multiple NEW_CONNECTION_ID messages. Each
NEW_CONNECTION_ID is marked with a sequence number. Connection IDs
MUST be used in the order in which they are numbered.
An endpoint that does not require the use of a connection ID should An endpoint that does not require the use of a connection ID should
not request that its peer use a connection ID. Such an endpoint does not request that its peer use a connection ID. Such an endpoint does
not need to provide new connection IDs using the NEW_CONNECTION_ID not need to provide new connection IDs using the NEW_CONNECTION_ID
frame. frame.
An endpoint which wishes to break linkability upon changing networks An endpoint might need to send packets on multiple networks without
MUST use the connection ID provided by its peer as well as receiving any response from its peer. To ensure that the endpoint is
incrementing the packet sequence number by an externally not linkable across each of these changes, a new connection ID is
unpredictable value computed as described in Section 6.8.5.1. Packet needed for each network. To support this, multiple NEW_CONNECTION_ID
number gaps are cumulative. An endpoint might skip connection IDs, messages are needed. Each NEW_CONNECTION_ID is marked with a
but it MUST ensure that it applies the associated packet number gaps sequence number. Connection IDs MUST be used in the order in which
for connection IDs that it skips in addition to the packet number gap they are numbered.
associated with the connection ID that it does use.
An endpoint that receives a packet that is marked with a new An endpoint that to break linkability upon changing networks MUST use
connection ID recovers the packet number by adding the cumulative a previously unused connection ID provided by its peer. Protection
packet number gap to its expected packet number. An endpoint MUST of packet numbers ensures that packet numbers cannot be used to
discard packets that contain a smaller gap than it advertised. correlate connections. Other properties of packets, such as timing
and size, might be used to correlate activity, but no explicit
correlation can be used to link activity across paths.
Clients MAY change connection ID at any time based on implementation- Clients MAY change connection ID at any time based on implementation-
specific concerns. For example, after a period of network inactivity specific concerns. For example, after a period of network inactivity
NAT rebinding might occur when the client begins sending data again. NAT rebinding might occur when the client begins sending data again.
A client might wish to reduce linkability by employing a new A client might wish to reduce linkability by employing a new
connection ID and source UDP port when sending traffic after a period connection ID and source UDP port when sending traffic after a period
of inactivity. Changing the UDP port from which it sends packets at of inactivity. Changing the UDP port from which it sends packets at
the same time might cause the packet to appear as a connection the same time might cause the packet to appear as a connection
migration. This ensures that the mechanisms that support migration migration. This ensures that the mechanisms that support migration
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An endpoint that receives a successfully authenticated packet with a An endpoint that receives a successfully authenticated packet with a
previously unused connection ID MUST use the next available previously unused connection ID MUST use the next available
connection ID for any packets it sends to that address. To avoid connection ID for any packets it sends to that address. To avoid
changing connection IDs multiple times when packets arrive out of changing connection IDs multiple times when packets arrive out of
order, endpoints MUST change only in response to a packet that order, endpoints MUST change only in response to a packet that
increases the largest received packet number. Failing to do this increases the largest received packet number. Failing to do this
could allow for use of that connection ID to link activity on new could allow for use of that connection ID to link activity on new
paths. There is no need to move to a new connection ID if the paths. There is no need to move to a new connection ID if the
address of a peer changes without also changing the connection ID. address of a peer changes without also changing the connection ID.
For instance, a server might provide a packet number gap of 7 6.9. Server's Preferred Address
associated with a new connection ID. If the server received packet
10 using the previous connection ID, it should expect packets on the
new connection ID to start at 18. A packet with the new connection
ID and a packet number of 17 is discarded as being in error.
6.8.5.1. Packet Number Gap QUIC allows servers to accept connections on one IP address and
attempt to transfer these connections to a more preferred address
shortly after the handshake. This is particularly useful when
clients initially connect to an address shared by multiple servers
but would prefer to use a unicast address to ensure connection
stability. This section describes the protocol for migrating a
connection to a preferred server address.
In order to avoid linkage, the packet number gap MUST be externally Migrating a connection to a new server address mid-connection is left
indistinguishable from random. The packet number gap for a for future work. If a client receives packets from a new server
connection ID with sequence number is computed by encoding the address not indicated by the preferred_address transport parameter,
sequence number as a 32-bit integer in big-endian format, and then the client SHOULD discard these packets.
computing:
Gap = HKDF-Expand-Label(packet_number_secret, 6.9.1. Communicating A Preferred Address
"QUIC packet sequence gap", sequence, 4)
The output of HKDF-Expand-Label is interpreted as a big-endian A server conveys a preferred address by including the
number. "packet_number_secret" is derived from the TLS key exchange, preferred_address transport parameter in the TLS handshake.
as described in Section 5.6 of [QUIC-TLS].
6.9. Connection Termination Once the handshake is finished, the client SHOULD initiate path
validation (see Section 6.7) of the server's preferred address using
the connection ID provided in the preferred_address transport
parameter.
If path validation succeeds, the client SHOULD immediately begin
sending all future packets to the new server address using the new
connection ID and discontinue use of the old server address. If path
validation fails, the client MUST continue sending all future packets
to the server's original IP address.
6.9.2. Responding to Connection Migration
A server might receive a packet addressed to its preferred IP address
at any time after the handshake is completed. If this packet
contains a PATH_CHALLENGE frame, the server sends a PATH_RESPONSE
frame as per Section 6.7, but the server MUST continue sending all
other packets from its original IP address.
The server SHOULD also initiate path validation of the client using
its preferred address and the address from which it received the
client probe. This helps to guard against spurious migration
initiated by an attacker.
Once the server has completed its path validation and has received a
non-probing packet with a new largest packet number on its preferred
address, the server begins sending to the client exclusively from its
preferred IP address. It SHOULD drop packets for this connection
received on the old IP address, but MAY continue to process delayed
packets.
6.9.3. Interaction of Client Migration and Preferred Address
A client might need to perform a connection migration before it has
migrated to the server's preferred address. In this case, the client
SHOULD perform path validation to both the original and preferred
server address from the client's new address concurrently.
If path validation of the server's preferred address succeeds, the
client MUST abandon validation of the original address and migrate to
using the server's preferred address. If path validation of the
server's preferred address fails, but validation of the server's
original address succeeds, the client MAY migrate to using the
original address from the client's new address.
If the connection to the server's preferred address is not from the
same client address, the server MUST protect against potential
attacks as described in Section 6.8.3.1 and Section 6.8.3.2. In
addition to intentional simultaneous migration, this might also occur
because the client's access network used a different NAT binding for
the server's preferred address.
Servers SHOULD initiate path validation to the client's new address
upon receiving a probe packet from a different address. Servers MUST
NOT send more than a minimum congestion window's worth of non-probing
packets to the new address before path validation is complete.
6.10. Connection Termination
Connections should remain open until they become idle for a pre- Connections should remain open until they become idle for a pre-
negotiated period of time. A QUIC connection, once established, can negotiated period of time. A QUIC connection, once established, can
be terminated in one of three ways: be terminated in one of three ways:
o idle timeout (Section 6.9.2) o idle timeout (Section 6.10.2)
o immediate close (Section 6.9.3)
o stateless reset (Section 6.9.4) o immediate close (Section 6.10.3)
6.9.1. Closing and Draining Connection States o stateless reset (Section 6.10.4)
6.10.1. Closing and Draining Connection States
The closing and draining connection states exist to ensure that The closing and draining connection states exist to ensure that
connections close cleanly and that delayed or reordered packets are connections close cleanly and that delayed or reordered packets are
properly discarded. These states SHOULD persist for three times the properly discarded. These states SHOULD persist for three times the
current Retransmission Timeout (RTO) interval as defined in current Retransmission Timeout (RTO) interval as defined in
[QUIC-RECOVERY]. [QUIC-RECOVERY].
An endpoint enters a closing period after initiating an immediate An endpoint enters a closing period after initiating an immediate
close (Section 6.9.3). While closing, an endpoint MUST NOT send close (Section 6.10.3). While closing, an endpoint MUST NOT send
packets unless they contain a CONNECTION_CLOSE or APPLICATION_CLOSE packets unless they contain a CONNECTION_CLOSE or APPLICATION_CLOSE
frame (see Section 6.9.3 for details). frame (see Section 6.10.3 for details).
In the closing state, only a packet containing a closing frame can be In the closing state, only a packet containing a closing frame can be
sent. An endpoint retains only enough information to generate a sent. An endpoint retains only enough information to generate a
packet containing a closing frame and to identify packets as packet containing a closing frame and to identify packets as
belonging to the connection. The connection ID and QUIC version is belonging to the connection. The connection ID and QUIC version is
sufficient information to identify packets for a closing connection; sufficient information to identify packets for a closing connection;
an endpoint can discard all other connection state. An endpoint MAY an endpoint can discard all other connection state. An endpoint MAY
retain packet protection keys for incoming packets to allow it to retain packet protection keys for incoming packets to allow it to
read and process a closing frame. read and process a closing frame.
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an abbreviated draining period which can allow for faster resource an abbreviated draining period which can allow for faster resource
recovery. Servers that retain an open socket for accepting new recovery. Servers that retain an open socket for accepting new
connections SHOULD NOT exit the closing or draining period early. connections SHOULD NOT exit the closing or draining period early.
Once the closing or draining period has ended, an endpoint SHOULD Once the closing or draining period has ended, an endpoint SHOULD
discard all connection state. This results in new packets on the discard all connection state. This results in new packets on the
connection being handled generically. For instance, an endpoint MAY connection being handled generically. For instance, an endpoint MAY
send a stateless reset in response to any further incoming packets. send a stateless reset in response to any further incoming packets.
The draining and closing periods do not apply when a stateless reset The draining and closing periods do not apply when a stateless reset
(Section 6.9.4) is sent. (Section 6.10.4) is sent.
An endpoint is not expected to handle key updates when it is closing An endpoint is not expected to handle key updates when it is closing
or draining. A key update might prevent the endpoint from moving or draining. A key update might prevent the endpoint from moving
from the closing state to draining, but it otherwise has no impact. from the closing state to draining, but it otherwise has no impact.
An endpoint could receive packets from a new source address, An endpoint could receive packets from a new source address,
indicating a client connection migration (Section 6.8), while in the indicating a client connection migration (Section 6.8), while in the
closing period. An endpoint in the closing state MUST strictly limit closing period. An endpoint in the closing state MUST strictly limit
the number of packets it sends to this new address until the address the number of packets it sends to this new address until the address
is validated (see Section 6.7). A server in the closing state MAY is validated (see Section 6.7). A server in the closing state MAY
instead choose to discard packets received from a new source address. instead choose to discard packets received from a new source address.
6.9.2. Idle Timeout 6.10.2. Idle Timeout
A connection that remains idle for longer than the idle timeout (see A connection that remains idle for longer than the idle timeout (see
Section 6.4.1) is closed. A connection enters the draining state Section 6.4.1) is closed. A connection enters the draining state
when the idle timeout expires. when the idle timeout expires.
The time at which an idle timeout takes effect won't be perfectly The time at which an idle timeout takes effect won't be perfectly
synchronized on both endpoints. An endpoint that sends packets near synchronized on both endpoints. An endpoint that sends packets near
the end of an idle period could have those packets discarded if its the end of an idle period could have those packets discarded if its
peer enters the draining state before the packet is received. peer enters the draining state before the packet is received.
6.9.3. Immediate Close 6.10.3. Immediate Close
An endpoint sends a closing frame, either CONNECTION_CLOSE or An endpoint sends a closing frame, either CONNECTION_CLOSE or
APPLICATION_CLOSE, to terminate the connection immediately. Either APPLICATION_CLOSE, to terminate the connection immediately. Either
closing frame causes all streams to immediately become closed; open closing frame causes all streams to immediately become closed; open
streams can be assumed to be implicitly reset. streams can be assumed to be implicitly reset.
After sending a closing frame, endpoints immediately enter the After sending a closing frame, endpoints immediately enter the
closing state. During the closing period, an endpoint that sends a closing state. During the closing period, an endpoint that sends a
closing frame SHOULD respond to any packet that it receives with closing frame SHOULD respond to any packet that it receives with
another packet containing a closing frame. To minimize the state another packet containing a closing frame. To minimize the state
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An immediate close can be used after an application protocol has An immediate close can be used after an application protocol has
arranged to close a connection. This might be after the application arranged to close a connection. This might be after the application
protocols negotiates a graceful shutdown. The application protocol protocols negotiates a graceful shutdown. The application protocol
exchanges whatever messages that are needed to cause both endpoints exchanges whatever messages that are needed to cause both endpoints
to agree to close the connection, after which the application to agree to close the connection, after which the application
requests that the connection be closed. The application protocol can requests that the connection be closed. The application protocol can
use an APPLICATION_CLOSE message with an appropriate error code to use an APPLICATION_CLOSE message with an appropriate error code to
signal closure. signal closure.
6.9.4. Stateless Reset 6.10.4. Stateless Reset
A stateless reset is provided as an option of last resort for a A stateless reset is provided as an option of last resort for a
server that does not have access to the state of a connection. A server that does not have access to the state of a connection. A
server crash or outage might result in clients continuing to send server crash or outage might result in clients continuing to send
data to a server that is unable to properly continue the connection. data to a server that is unable to properly continue the connection.
A server that wishes to communicate a fatal connection error MUST use A server that wishes to communicate a fatal connection error MUST use
a closing frame if it has sufficient state to do so. a closing frame if it has sufficient state to do so.
To support this process, the server sends a stateless_reset_token To support this process, the server sends a stateless_reset_token
value during the handshake in the transport parameters. This value value during the handshake in the transport parameters. This value
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and recovered. In this case, clients will need to rely on other and recovered. In this case, clients will need to rely on other
methods - such as timers - to detect that the connection has methods - such as timers - to detect that the connection has
failed. failed.
o The randomly generated connection ID can be used by entities other o The randomly generated connection ID can be used by entities other
than the client to identify this as a potential stateless reset. than the client to identify this as a potential stateless reset.
A server that occasionally uses different connection IDs might A server that occasionally uses different connection IDs might
introduce some uncertainty about this. introduce some uncertainty about this.
The Packet Number field is set to a randomized value. The server The Packet Number field is set to a randomized value. The server
SHOULD send a packet with a short header and a type of 0x1F. This SHOULD send a packet with a short header and a packet number length
produces the shortest possible packet number encoding, which of 1 octet. Using the shortest possible packet number encoding
minimizes the perceived gap between the last packet that the server minimizes the perceived gap between the last packet that the server
sent and this packet. A server MAY use a different short header sent and this packet. A server MAY indicate a different packet
type, indicating a different packet number length, but a longer number length, but a longer packet number encoding might allow this
packet number encoding might allow this message to be identified as a message to be identified as a stateless reset more easily using
stateless reset more easily using heuristics. heuristics.
After the Packet Number, the server pads the message with an After the Packet Number, the server pads the message with an
arbitrary number of octets containing random values. arbitrary number of octets containing random values.
Finally, the last 16 octets of the packet are set to the value of the Finally, the last 16 octets of the packet are set to the value of the
Stateless Reset Token. Stateless Reset Token.
A stateless reset is not appropriate for signaling error conditions. A stateless reset is not appropriate for signaling error conditions.
An endpoint that wishes to communicate a fatal connection error MUST An endpoint that wishes to communicate a fatal connection error MUST
use a CONNECTION_CLOSE or APPLICATION_CLOSE frame if it has use a CONNECTION_CLOSE or APPLICATION_CLOSE frame if it has
sufficient state to do so. sufficient state to do so.
This stateless reset design is specific to QUIC version 1. A server This stateless reset design is specific to QUIC version 1. A server
that supports multiple versions of QUIC needs to generate a stateless that supports multiple versions of QUIC needs to generate a stateless
reset that will be accepted by clients that support any version that reset that will be accepted by clients that support any version that
the server might support (or might have supported prior to losing the server might support (or might have supported prior to losing
state). Designers of new versions of QUIC need to be aware of this state). Designers of new versions of QUIC need to be aware of this
and either reuse this design, or use a portion of the packet other and either reuse this design, or use a portion of the packet other
than the last 16 octets for carrying data. than the last 16 octets for carrying data.
6.9.4.1. Detecting a Stateless Reset 6.10.4.1. Detecting a Stateless Reset
A client detects a potential stateless reset when a packet with a A client detects a potential stateless reset when a packet with a
short header either cannot be decrypted or is marked as a duplicate short header either cannot be decrypted or is marked as a duplicate
packet. The client then compares the last 16 octets of the packet packet. The client then compares the last 16 octets of the packet
with the Stateless Reset Token provided by the server in its with the Stateless Reset Token provided by the server in its
transport parameters. If these values are identical, the client MUST transport parameters. If these values are identical, the client MUST
enter the draining period and not send any further packets on this enter the draining period and not send any further packets on this
connection. If the comparison fails, the packet can be discarded. connection. If the comparison fails, the packet can be discarded.
6.9.4.2. Calculating a Stateless Reset Token 6.10.4.2. Calculating a Stateless Reset Token
The stateless reset token MUST be difficult to guess. In order to The stateless reset token MUST be difficult to guess. In order to
create a Stateless Reset Token, a server could randomly generate create a Stateless Reset Token, a server could randomly generate
[RFC4086] a secret for every connection that it creates. However, [RFC4086] a secret for every connection that it creates. However,
this presents a coordination problem when there are multiple servers this presents a coordination problem when there are multiple servers
in a cluster or a storage problem for a server that might lose state. in a cluster or a storage problem for a server that might lose state.
Stateless reset specifically exists to handle the case where state is Stateless reset specifically exists to handle the case where state is
lost, so this approach is suboptimal. lost, so this approach is suboptimal.
A single static key can be used across all connections to the same A single static key can be used across all connections to the same
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protection. protection.
7. Frame Types and Formats 7. Frame Types and Formats
As described in Section 5, packets contain one or more frames. This As described in Section 5, packets contain one or more frames. This
section describes the format and semantics of the core QUIC frame section describes the format and semantics of the core QUIC frame
types. types.
7.1. Variable-Length Integer Encoding 7.1. Variable-Length Integer Encoding
QUIC frames use a common variable-length encoding for all non- QUIC frames commonly use a variable-length encoding for non-negative
negative integer values. This encoding ensures that smaller integer integer values. This encoding ensures that smaller integer values
values need fewer octets to encode. need fewer octets to encode.
The QUIC variable-length integer encoding reserves the two most The QUIC variable-length integer encoding reserves the two most
significant bits of the first octet to encode the base 2 logarithm of significant bits of the first octet to encode the base 2 logarithm of
the integer encoding length in octets. The integer value is encoded the integer encoding length in octets. The integer value is encoded
on the remaining bits, in network byte order. on the remaining bits, in network byte order.
This means that integers are encoded on 1, 2, 4, or 8 octets and can This means that integers are encoded on 1, 2, 4, or 8 octets and can
encode 6, 14, 30, or 62 bit values respectively. Table 4 summarizes encode 6, 14, 30, or 62 bit values respectively. Table 4 summarizes
the encoding properties. the encoding properties.
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application or application protocol wishes to prevent the connection application or application protocol wishes to prevent the connection
from timing out. An application protocol SHOULD provide guidance from timing out. An application protocol SHOULD provide guidance
about the conditions under which generating a PING is recommended. about the conditions under which generating a PING is recommended.
This guidance SHOULD indicate whether it is the client or the server This guidance SHOULD indicate whether it is the client or the server
that is expected to send the PING. Having both endpoints send PING that is expected to send the PING. Having both endpoints send PING
frames without coordination can produce an excessive number of frames without coordination can produce an excessive number of
packets and poor performance. packets and poor performance.
A connection will time out if no packets are sent or received for a A connection will time out if no packets are sent or received for a
period longer than the time specified in the idle_timeout transport period longer than the time specified in the idle_timeout transport
parameter (see Section 6.9). However, state in middleboxes might parameter (see Section 6.10). However, state in middleboxes might
time out earlier than that. Though REQ-5 in [RFC4787] recommends a 2 time out earlier than that. Though REQ-5 in [RFC4787] recommends a 2
minute timeout interval, experience shows that sending packets every minute timeout interval, experience shows that sending packets every
15 to 30 seconds is necessary to prevent the majority of middleboxes 15 to 30 seconds is necessary to prevent the majority of middleboxes
from losing state for UDP flows. from losing state for UDP flows.
7.10. BLOCKED Frame 7.10. BLOCKED Frame
A sender SHOULD send a BLOCKED frame (type=0x08) when it wishes to A sender SHOULD send a BLOCKED frame (type=0x08) when it wishes to
send data, but is unable to due to connection-level flow control (see send data, but is unable to due to connection-level flow control (see
Section 10.2.1). BLOCKED frames can be used as input to tuning of Section 10.2.1). BLOCKED frames can be used as input to tuning of
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Length: An 8-bit unsigned integer containing the length of the Length: An 8-bit unsigned integer containing the length of the
connection ID. Values less than 4 and greater than 18 are invalid connection ID. Values less than 4 and greater than 18 are invalid
and MUST be treated as a connection error of type and MUST be treated as a connection error of type
PROTOCOL_VIOLATION. PROTOCOL_VIOLATION.
Connection ID: A connection ID of the specified length. Connection ID: A connection ID of the specified length.
Stateless Reset Token: A 128-bit value that will be used to for a Stateless Reset Token: A 128-bit value that will be used to for a
stateless reset when the associated connection ID is used (see stateless reset when the associated connection ID is used (see
Section 6.9.4). Section 6.10.4).
An endpoint MUST NOT send this frame if it currently requires that An endpoint MUST NOT send this frame if it currently requires that
its peer send packets with a zero-length Destination Connection ID. its peer send packets with a zero-length Destination Connection ID.
Changing the length of a connection ID to or from zero-length makes Changing the length of a connection ID to or from zero-length makes
it difficult to identify when the value of the connection ID changed. it difficult to identify when the value of the connection ID changed.
An endpoint that is sending packets with a zero-length Destination An endpoint that is sending packets with a zero-length Destination
Connection ID MUST treat receipt of a NEW_CONNECTION_ID frame as a Connection ID MUST treat receipt of a NEW_CONNECTION_ID frame as a
connection error of type PROTOCOL_VIOLATION. connection error of type PROTOCOL_VIOLATION.
7.14. STOP_SENDING Frame 7.14. STOP_SENDING Frame
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Stream ID: A variable-length integer carrying the Stream ID of the Stream ID: A variable-length integer carrying the Stream ID of the
stream being ignored. stream being ignored.
Application Error Code: A 16-bit, application-specified reason the Application Error Code: A 16-bit, application-specified reason the
sender is ignoring the stream (see Section 11.4). sender is ignoring the stream (see Section 11.4).
7.15. ACK Frame 7.15. ACK Frame
Receivers send ACK frames (type=0x0d) to inform senders which packets Receivers send ACK frames (type=0x0d) to inform senders which packets
they have received and processed. A sent packet that has never been they have received and processed. The ACK frame contains any number
acknowledged is missing. The ACK frame contains any number of ACK of ACK blocks. ACK blocks are ranges of acknowledged packets.
blocks. ACK blocks are ranges of acknowledged packets.
Unlike TCP SACKs, QUIC acknowledgements are irrevocable. Once a QUIC acknowledgements are irrevocable. Once acknowledged, a packet
packet has been acknowledged, even if it does not appear in a future remains acknowledged, even if it does not appear in a future ACK
ACK frame, it remains acknowledged. frame. This is unlike TCP SACKs ([RFC2018]).
A client MUST NOT acknowledge Retry packets. Retry packets include A client MUST NOT acknowledge Retry packets. Retry packets include
the packet number from the Initial packet it responds to. Version the packet number from the Initial packet it responds to. Version
Negotiation packets cannot be acknowledged because they do not Negotiation packets cannot be acknowledged because they do not
contain a packet number. Rather than relying on ACK frames, these contain a packet number. Rather than relying on ACK frames, these
packets are implicitly acknowledged by the next Initial packet sent packets are implicitly acknowledged by the next Initial packet sent
by the client. by the client.
An ACK frame is shown below. An ACK frame is shown below.
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when the OFF bit is set to 1. When the Offset field is absent, when the OFF bit is set to 1. When the Offset field is absent,
the offset is 0. the offset is 0.
Length: A variable-length integer specifying the length of the Length: A variable-length integer specifying the length of the
Stream Data field in this STREAM frame. This field is present Stream Data field in this STREAM frame. This field is present
when the LEN bit is set to 1. When the LEN bit is set to 0, the when the LEN bit is set to 1. When the LEN bit is set to 0, the
Stream Data field consumes all the remaining octets in the packet. Stream Data field consumes all the remaining octets in the packet.
Stream Data: The bytes from the designated stream to be delivered. Stream Data: The bytes from the designated stream to be delivered.
A stream frame's Stream Data MUST NOT be empty, unless the offset is When a Stream Data field has a length of 0, the offset in the STREAM
0 or the FIN bit is set. When the FIN flag is sent on an empty frame is the offset of the next byte that would be sent.
STREAM frame, the offset in the STREAM frame is the offset of the
next byte that would be sent.
The first byte in the stream has an offset of 0. The largest offset The first byte in the stream has an offset of 0. The largest offset
delivered on a stream - the sum of the re-constructed offset and data delivered on a stream - the sum of the re-constructed offset and data
length - MUST be less than 2^62. length - MUST be less than 2^62.
Stream multiplexing is achieved by interleaving STREAM frames from Stream multiplexing is achieved by interleaving STREAM frames from
multiple streams into one or more QUIC packets. A single QUIC packet multiple streams into one or more QUIC packets. A single QUIC packet
can include multiple STREAM frames from one or more streams. can include multiple STREAM frames from one or more streams.
Implementation note: One of the benefits of QUIC is avoidance of Implementation note: One of the benefits of QUIC is avoidance of
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acknowledged by the peer (that is, either the "Reset Recvd" or acknowledged by the peer (that is, either the "Reset Recvd" or
"Data Recvd" state is reached on the send stream). The content of "Data Recvd" state is reached on the send stream). The content of
a RST_STREAM frame MUST NOT change when it is sent again. a RST_STREAM frame MUST NOT change when it is sent again.
o Similarly, a request to cancel stream transmission, as encoded in o Similarly, a request to cancel stream transmission, as encoded in
a STOP_SENDING frame, is sent until the receive stream enters a STOP_SENDING frame, is sent until the receive stream enters
either a "Data Recvd" or "Reset Recvd" state, see Section 9.3. either a "Data Recvd" or "Reset Recvd" state, see Section 9.3.
o Connection close signals, including those that use o Connection close signals, including those that use
CONNECTION_CLOSE and APPLICATION_CLOSE frames, are not sent again CONNECTION_CLOSE and APPLICATION_CLOSE frames, are not sent again
when packet loss is detected, but as described in Section 6.9. when packet loss is detected, but as described in Section 6.10.
o The current connection maximum data is sent in MAX_DATA frames. o The current connection maximum data is sent in MAX_DATA frames.
An updated value is sent in a MAX_DATA frame if the packet An updated value is sent in a MAX_DATA frame if the packet
containing the most recently sent MAX_DATA frame is declared lost, containing the most recently sent MAX_DATA frame is declared lost,
or when the endpoint decides to update the limit. Care is or when the endpoint decides to update the limit. Care is
necessary to avoid sending this frame too often as the limit can necessary to avoid sending this frame too often as the limit can
increase frequently and cause an unnecessarily large number of increase frequently and cause an unnecessarily large number of
MAX_DATA frames to be sent. MAX_DATA frames to be sent.
o The current maximum stream data offset is sent in MAX_STREAM_DATA o The current maximum stream data offset is sent in MAX_STREAM_DATA
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limit might exist. limit might exist.
If a QUIC endpoint determines that the PMTU between any pair of local If a QUIC endpoint determines that the PMTU between any pair of local
and remote IP addresses has fallen below 1280 octets, it MUST and remote IP addresses has fallen below 1280 octets, it MUST
immediately cease sending QUIC packets on the affected path. This immediately cease sending QUIC packets on the affected path. This
could result in termination of the connection if an alternative path could result in termination of the connection if an alternative path
cannot be found. cannot be found.
8.4.1. Special Considerations for PMTU Discovery 8.4.1. Special Considerations for PMTU Discovery
Traditional ICMP-based path MTU discovery in IPv4 [RFC1191] is Traditional ICMP-based path MTU discovery in IPv4 [PMTUDv4] is
potentially vulnerable to off-path attacks that successfully guess potentially vulnerable to off-path attacks that successfully guess
the IP/port 4-tuple and reduce the MTU to a bandwidth-inefficient the IP/port 4-tuple and reduce the MTU to a bandwidth-inefficient
value. TCP connections mitigate this risk by using the (at minimum) value. TCP connections mitigate this risk by using the (at minimum)
8 bytes of transport header echoed in the ICMP message to validate 8 bytes of transport header echoed in the ICMP message to validate
the TCP sequence number as valid for the current connection. the TCP sequence number as valid for the current connection.
However, as QUIC operates over UDP, in IPv4 the echoed information However, as QUIC operates over UDP, in IPv4 the echoed information
could consist only of the IP and UDP headers, which usually has could consist only of the IP and UDP headers, which usually has
insufficient entropy to mitigate off-path attacks. insufficient entropy to mitigate off-path attacks.
As a result, endpoints that implement PMTUD in IPv4 SHOULD take steps As a result, endpoints that implement PMTUD in IPv4 SHOULD take steps
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o Store additional information from the IP or UDP headers from DF o Store additional information from the IP or UDP headers from DF
packets (for example, the IP ID or UDP checksum) to further packets (for example, the IP ID or UDP checksum) to further
authenticate incoming Datagram Too Big messages. authenticate incoming Datagram Too Big messages.
o Any reduction in PMTU due to a report contained in an ICMP packet o Any reduction in PMTU due to a report contained in an ICMP packet
is provisional until QUIC's loss detection algorithm determines is provisional until QUIC's loss detection algorithm determines
that the packet is actually lost. that the packet is actually lost.
8.4.2. Special Considerations for Packetization Layer PMTU Discovery 8.4.2. Special Considerations for Packetization Layer PMTU Discovery
The PADDING frame provides a useful option for PMTU probe packets The PADDING frame provides a useful option for PMTU probe packets.
that does not exist in other transports. PADDING frames generate PADDING frames generate acknowledgements, but they need not be
acknowledgements, but their content need not be delivered reliably. delivered reliably. As a result, the loss of PADDING frames in probe
PADDING frames may delay the delivery of application data, as they packets does not require delay-inducing retransmission. However,
consume the congestion window. However, by definition their likely PADDING frames do consume congestion window, which may delay the
loss in a probe packet does not require delay-inducing retransmission transmission of subsequent application data.
of application data.
When implementing the algorithm in Section 7.2 of [RFC4821], the When implementing the algorithm in Section 7.2 of [PLPMTUD], the
initial value of search_low SHOULD be consistent with the IPv6 initial value of search_low SHOULD be consistent with the IPv6
minimum packet size. Paths that do not support this size cannot minimum packet size. Paths that do not support this size cannot
deliver Initial packets, and therefore are not QUIC-compliant. deliver Initial packets, and therefore are not QUIC-compliant.
Section 7.3 of [RFC4821] discusses tradeoffs between small and large Section 7.3 of [PLPMTUD] discusses tradeoffs between small and large
increases in the size of probe packets. As QUIC probe packets need increases in the size of probe packets. As QUIC probe packets need
not contain application data, aggressive increases in probe size not contain application data, aggressive increases in probe size
carry fewer consequences. carry fewer consequences.
9. Streams: QUIC's Data Structuring Abstraction 9. Streams: QUIC's Data Structuring Abstraction
Streams in QUIC provide a lightweight, ordered byte-stream Streams in QUIC provide a lightweight, ordered byte-stream
abstraction. abstraction.
There are two basic types of stream in QUIC. Unidirectional streams There are two basic types of stream in QUIC. Unidirectional streams
skipping to change at page 80, line 22 skipping to change at page 82, line 19
encapsulating data on a stream until the stream is terminated in that encapsulating data on a stream until the stream is terminated in that
direction. Streams are an ordered byte-stream abstraction, and they direction. Streams are an ordered byte-stream abstraction, and they
have no other structure within them. STREAM frame boundaries are not have no other structure within them. STREAM frame boundaries are not
expected to be preserved in retransmissions from the sender or during expected to be preserved in retransmissions from the sender or during
delivery to the application at the receiver. delivery to the application at the receiver.
When new data is to be sent on a stream, a sender MUST set the When new data is to be sent on a stream, a sender MUST set the
encapsulating STREAM frame's offset field to the stream offset of the encapsulating STREAM frame's offset field to the stream offset of the
first byte of this new data. The first octet of data on a stream has first byte of this new data. The first octet of data on a stream has
an offset of 0. An endpoint is expected to send every stream octet. an offset of 0. An endpoint is expected to send every stream octet.
The largest offset delivered on a stream MUST be less than 2^62. A The largest offset delivered on a stream MUST be less than 2^62.
receiver MUST ensure that received stream data is delivered to the
application as an ordered byte-stream. Data received out of order QUIC makes no specific allowances for partial reliability or delivery
MUST be buffered for later delivery, as long as it is not in of stream data out of order. Endpoints MUST be able to deliver
violation of the receiver's flow control limits. stream data to an application as an ordered byte-stream. Delivering
an ordered byte-stream requires that an endpoint buffer any data that
is received out of order, up to the advertised flow control limit.
An endpoint could receive the same octets multiple times; octets that
have already been received can be discarded. The value for a given
octet MUST NOT change if it is sent multiple times; an endpoint MAY
treat receipt of a changed octet as a connection error of type
PROTOCOL_VIOLATION.
An endpoint MUST NOT send data on any stream without ensuring that it An endpoint MUST NOT send data on any stream without ensuring that it
is within the data limits set by its peer. The cryptographic is within the data limits set by its peer. The cryptographic
handshake stream, Stream 0, is exempt from the connection-level data handshake stream, Stream 0, is exempt from the connection-level data
limits established by MAX_DATA. Data on stream 0 other than the limits established by MAX_DATA. Data on stream 0 other than the
initial cryptographic handshake message is still subject to stream- initial cryptographic handshake message is still subject to stream-
level data limits and MAX_STREAM_DATA. This message is exempt from level data limits and MAX_STREAM_DATA. This message is exempt from
flow control because it needs to be sent in a single packet flow control because it needs to be sent in a single packet
regardless of the server's flow control state. This rule applies regardless of the server's flow control state. This rule applies
even for 0-RTT handshakes where the remembered value of even for 0-RTT handshakes where the remembered value of
skipping to change at page 86, line 12 skipping to change at page 88, line 12
error to its peer. Both transport-level and application-level errors error to its peer. Both transport-level and application-level errors
can affect an entire connection (see Section 11.1), while only can affect an entire connection (see Section 11.1), while only
application-level errors can be isolated to a single stream (see application-level errors can be isolated to a single stream (see
Section 11.2). Section 11.2).
The most appropriate error code (Section 11.3) SHOULD be included in The most appropriate error code (Section 11.3) SHOULD be included in
the frame that signals the error. Where this specification the frame that signals the error. Where this specification
identifies error conditions, it also identifies the error code that identifies error conditions, it also identifies the error code that
is used. is used.
A stateless reset (Section 6.9.4) is not suitable for any error that A stateless reset (Section 6.10.4) is not suitable for any error that
can be signaled with a CONNECTION_CLOSE, APPLICATION_CLOSE, or can be signaled with a CONNECTION_CLOSE, APPLICATION_CLOSE, or
RST_STREAM frame. A stateless reset MUST NOT be used by an endpoint RST_STREAM frame. A stateless reset MUST NOT be used by an endpoint
that has the state necessary to send a frame on the connection. that has the state necessary to send a frame on the connection.
11.1. Connection Errors 11.1. Connection Errors
Errors that result in the connection being unusable, such as an Errors that result in the connection being unusable, such as an
obvious violation of protocol semantics or corruption of state that obvious violation of protocol semantics or corruption of state that
affects an entire connection, MUST be signaled using a affects an entire connection, MUST be signaled using a
CONNECTION_CLOSE or APPLICATION_CLOSE frame (Section 7.4, CONNECTION_CLOSE or APPLICATION_CLOSE frame (Section 7.4,
skipping to change at page 86, line 43 skipping to change at page 88, line 43
packet that is lost. An endpoint SHOULD be prepared to retransmit a packet that is lost. An endpoint SHOULD be prepared to retransmit a
packet containing either frame type if it receives more packets on a packet containing either frame type if it receives more packets on a
terminated connection. Limiting the number of retransmissions and terminated connection. Limiting the number of retransmissions and
the time over which this final packet is sent limits the effort the time over which this final packet is sent limits the effort
expended on terminated connections. expended on terminated connections.
An endpoint that chooses not to retransmit packets containing An endpoint that chooses not to retransmit packets containing
CONNECTION_CLOSE or APPLICATION_CLOSE risks a peer missing the first CONNECTION_CLOSE or APPLICATION_CLOSE risks a peer missing the first
such packet. The only mechanism available to an endpoint that such packet. The only mechanism available to an endpoint that
continues to receive data for a terminated connection is to use the continues to receive data for a terminated connection is to use the
stateless reset process (Section 6.9.4). stateless reset process (Section 6.10.4).
An endpoint that receives an invalid CONNECTION_CLOSE or An endpoint that receives an invalid CONNECTION_CLOSE or
APPLICATION_CLOSE frame MUST NOT signal the existence of the error to APPLICATION_CLOSE frame MUST NOT signal the existence of the error to
its peer. its peer.
11.2. Stream Errors 11.2. Stream Errors
If an application-level error affects a single stream, but otherwise If an application-level error affects a single stream, but otherwise
leaves the connection in a recoverable state, the endpoint can send a leaves the connection in a recoverable state, the endpoint can send a
RST_STREAM frame (Section 7.3) with an appropriate error code to RST_STREAM frame (Section 7.3) with an appropriate error code to
skipping to change at page 89, line 11 skipping to change at page 91, line 11
the management of application error codes are left to application the management of application error codes are left to application
protocols. Application protocol error codes are used for the protocols. Application protocol error codes are used for the
RST_STREAM (Section 7.3) and APPLICATION_CLOSE (Section 7.5) frames. RST_STREAM (Section 7.3) and APPLICATION_CLOSE (Section 7.5) frames.
There is no restriction on the use of the 16-bit error code space for There is no restriction on the use of the 16-bit error code space for
application protocols. However, QUIC reserves the error code with a application protocols. However, QUIC reserves the error code with a
value of 0 to mean STOPPING. The application error code of STOPPING value of 0 to mean STOPPING. The application error code of STOPPING
(0) is used by the transport to cancel a stream in response to (0) is used by the transport to cancel a stream in response to
receipt of a STOP_SENDING frame. receipt of a STOP_SENDING frame.
12. Security and Privacy Considerations 12. Security Considerations
12.1. Spoofed ACK Attack 12.1. Spoofed ACK Attack
An attacker might be able to receive an address validation token An attacker might be able to receive an address validation token
(Section 6.6) from the server and then release the IP address it used (Section 6.6) from the server and then release the IP address it used
to acquire that token. The attacker may, in the future, spoof this to acquire that token. The attacker may, in the future, spoof this
same address (which now presumably addresses a different endpoint), same address (which now presumably addresses a different endpoint),
and initiate a 0-RTT connection with a server on the victim's behalf. and initiate a 0-RTT connection with a server on the victim's behalf.
The attacker can then spoof ACK frames to the server which cause the The attacker can then spoof ACK frames to the server which cause the
server to send excessive amounts of data toward the new owner of the server to send excessive amounts of data toward the new owner of the
skipping to change at page 89, line 49 skipping to change at page 91, line 49
forward secure key, the attacker will not be able to generate forward secure key, the attacker will not be able to generate
forward-secure protected packets with ACK frames. forward-secure protected packets with ACK frames.
12.2. Optimistic ACK Attack 12.2. Optimistic ACK Attack
An endpoint that acknowledges packets it has not received might cause An endpoint that acknowledges packets it has not received might cause
a congestion controller to permit sending at rates beyond what the a congestion controller to permit sending at rates beyond what the
network supports. An endpoint MAY skip packet numbers when sending network supports. An endpoint MAY skip packet numbers when sending
packets to detect this behavior. An endpoint can then immediately packets to detect this behavior. An endpoint can then immediately
close the connection with a connection error of type close the connection with a connection error of type
PROTOCOL_VIOLATION (see Section 6.9.3). PROTOCOL_VIOLATION (see Section 6.10.3).
12.3. Slowloris Attacks 12.3. Slowloris Attacks
The attacks commonly known as Slowloris [SLOWLORIS] try to keep many The attacks commonly known as Slowloris [SLOWLORIS] try to keep many
connections to the target endpoint open and hold them open as long as connections to the target endpoint open and hold them open as long as
possible. These attacks can be executed against a QUIC endpoint by possible. These attacks can be executed against a QUIC endpoint by
generating the minimum amount of activity necessary to avoid being generating the minimum amount of activity necessary to avoid being
closed for inactivity. This might involve sending small amounts of closed for inactivity. This might involve sending small amounts of
data, gradually opening flow control windows in order to control the data, gradually opening flow control windows in order to control the
sender rate, or manufacturing ACK frames that simulate a high loss sender rate, or manufacturing ACK frames that simulate a high loss
skipping to change at page 92, line 5 skipping to change at page 94, line 5
the value. the value.
The nominated expert(s) verify that a specification exists and is The nominated expert(s) verify that a specification exists and is
readily accessible. The expert(s) are encouraged to be biased readily accessible. The expert(s) are encouraged to be biased
towards approving registrations unless they are abusive, frivolous, towards approving registrations unless they are abusive, frivolous,
or actively harmful (not merely aesthetically displeasing, or or actively harmful (not merely aesthetically displeasing, or
architecturally dubious). architecturally dubious).
The initial contents of this registry are shown in Table 7. The initial contents of this registry are shown in Table 7.
+--------+----------------------------+---------------+ +--------+--------------------------+---------------+
| Value | Parameter Name | Specification | | Value | Parameter Name | Specification |
+--------+----------------------------+---------------+ +--------+--------------------------+---------------+
| 0x0000 | initial_max_stream_data | Section 6.4.1 | | 0x0000 | initial_max_stream_data | Section 6.4.1 |
| | | | | | | |
| 0x0001 | initial_max_data | Section 6.4.1 | | 0x0001 | initial_max_data | Section 6.4.1 |
| | | | | | | |
| 0x0002 | initial_max_stream_id_bidi | Section 6.4.1 | | 0x0002 | initial_max_bidi_streams | Section 6.4.1 |
| | | | | | | |
| 0x0003 | idle_timeout | Section 6.4.1 | | 0x0003 | idle_timeout | Section 6.4.1 |
| | | | | | | |
| 0x0005 | max_packet_size | Section 6.4.1 | | 0x0004 | preferred_address | Section 6.4.1 |
| | | | | | | |
| 0x0006 | stateless_reset_token | Section 6.4.1 | | 0x0005 | max_packet_size | Section 6.4.1 |
| | | | | | | |
| 0x0007 | ack_delay_exponent | Section 6.4.1 | | 0x0006 | stateless_reset_token | Section 6.4.1 |
| | | | | | | |
| 0x0008 | initial_max_stream_id_uni | Section 6.4.1 | | 0x0007 | ack_delay_exponent | Section 6.4.1 |
+--------+----------------------------+---------------+ | | | |
| 0x0008 | initial_max_uni_streams | Section 6.4.1 |
+--------+--------------------------+---------------+
Table 7: Initial QUIC Transport Parameters Entries Table 7: Initial QUIC Transport Parameters Entries
13.2. QUIC Transport Error Codes Registry 13.2. QUIC Transport Error Codes Registry
IANA [SHALL add/has added] a registry for "QUIC Transport Error IANA [SHALL add/has added] a registry for "QUIC Transport Error
Codes" under a "QUIC Protocol" heading. Codes" under a "QUIC Protocol" heading.
The "QUIC Transport Error Codes" registry governs a 16-bit space. The "QUIC Transport Error Codes" registry governs a 16-bit space.
This space is split into two spaces that are governed by different This space is split into two spaces that are governed by different
skipping to change at page 94, line 38 skipping to change at page 96, line 38
DOI 10.17487/RFC1191, November 1990, DOI 10.17487/RFC1191, November 1990,
<https://www.rfc-editor.org/info/rfc1191>. <https://www.rfc-editor.org/info/rfc1191>.
[PMTUDv6] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., [PMTUDv6] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed.,
"Path MTU Discovery for IP version 6", STD 87, RFC 8201, "Path MTU Discovery for IP version 6", STD 87, RFC 8201,
DOI 10.17487/RFC8201, July 2017, DOI 10.17487/RFC8201, July 2017,
<https://www.rfc-editor.org/info/rfc8201>. <https://www.rfc-editor.org/info/rfc8201>.
[QUIC-RECOVERY] [QUIC-RECOVERY]
Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection
and Congestion Control", draft-ietf-quic-recovery-10 (work and Congestion Control", draft-ietf-quic-recovery-12 (work
in progress), April 2018. in progress), May 2018.
[QUIC-TLS] [QUIC-TLS]
Thomson, M., Ed. and S. Turner, Ed., "Using Transport Thomson, M., Ed. and S. Turner, Ed., "Using Transport
Layer Security (TLS) to Secure QUIC", draft-ietf-quic- Layer Security (TLS) to Secure QUIC", draft-ietf-quic-
tls-10 (work in progress), April 2018. tls-12 (work in progress), May 2018.
[RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191,
DOI 10.17487/RFC1191, November 1990,
<https://www.rfc-editor.org/info/rfc1191>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
2003, <https://www.rfc-editor.org/info/rfc3629>. 2003, <https://www.rfc-editor.org/info/rfc3629>.
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086, "Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005, DOI 10.17487/RFC4086, June 2005,
<https://www.rfc-editor.org/info/rfc4086>. <https://www.rfc-editor.org/info/rfc4086>.
[RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU
Discovery", RFC 4821, DOI 10.17487/RFC4821, March 2007,
<https://www.rfc-editor.org/info/rfc4821>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
14.2. Informative References 14.2. Informative References
skipping to change at page 95, line 45 skipping to change at page 97, line 36
Roskind, J., "QUIC: Multiplexed Transport Over UDP", Roskind, J., "QUIC: Multiplexed Transport Over UDP",
December 2013, <https://goo.gl/dMVtFi>. December 2013, <https://goo.gl/dMVtFi>.
[HTTP2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext [HTTP2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Transfer Protocol Version 2 (HTTP/2)", RFC 7540, Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
DOI 10.17487/RFC7540, May 2015, DOI 10.17487/RFC7540, May 2015,
<https://www.rfc-editor.org/info/rfc7540>. <https://www.rfc-editor.org/info/rfc7540>.
[QUIC-INVARIANTS] [QUIC-INVARIANTS]
Thomson, M., "Version-Independent Properties of QUIC", Thomson, M., "Version-Independent Properties of QUIC",
draft-ietf-quic-invariants-01 (work in progress), April draft-ietf-quic-invariants-01 (work in progress), May
2018. 2018.
[RFC2018] Mathis, M., Mahdavi, J., Floyd, S., and A. Romanow, "TCP
Selective Acknowledgment Options", RFC 2018,
DOI 10.17487/RFC2018, October 1996,
<https://www.rfc-editor.org/info/rfc2018>.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104, Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997, DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/info/rfc2104>. <https://www.rfc-editor.org/info/rfc2104>.
[RFC2360] Scott, G., "Guide for Internet Standards Writers", BCP 22, [RFC2360] Scott, G., "Guide for Internet Standards Writers", BCP 22,
RFC 2360, DOI 10.17487/RFC2360, June 1998, RFC 2360, DOI 10.17487/RFC2360, June 1998,
<https://www.rfc-editor.org/info/rfc2360>. <https://www.rfc-editor.org/info/rfc2360>.
[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address [RFC4787] Audet, F., Ed. and C. Jennings, "Network Address
skipping to change at page 96, line 33 skipping to change at page 98, line 29
[SLOWLORIS] [SLOWLORIS]
RSnake Hansen, R., "Welcome to Slowloris...", June 2009, RSnake Hansen, R., "Welcome to Slowloris...", June 2009,
<https://web.archive.org/web/20150315054838/ <https://web.archive.org/web/20150315054838/
http://ha.ckers.org/slowloris/>. http://ha.ckers.org/slowloris/>.
[SST] Ford, B., "Structured streams", ACM SIGCOMM Computer [SST] Ford, B., "Structured streams", ACM SIGCOMM Computer
Communication Review Vol. 37, pp. 361, Communication Review Vol. 37, pp. 361,
DOI 10.1145/1282427.1282421, October 2007. DOI 10.1145/1282427.1282421, October 2007.
14.3. URIs
[1] https://mailarchive.ietf.org/arch/search/?email_list=quic
[2] https://github.com/quicwg
[3] https://github.com/quicwg/base-drafts/labels/-transport
[4] https://github.com/quicwg/base-drafts/wiki/QUIC-Versions
Appendix A. Contributors Appendix A. Contributors
The original authors of this specification were Ryan Hamilton, Jana The original authors of this specification were Ryan Hamilton, Jana
Iyengar, Ian Swett, and Alyssa Wilk. Iyengar, Ian Swett, and Alyssa Wilk.
The original design and rationale behind this protocol draw The original design and rationale behind this protocol draw
significantly from work by Jim Roskind [EARLY-DESIGN]. In significantly from work by Jim Roskind [EARLY-DESIGN]. In
alphabetical order, the contributors to the pre-IETF QUIC project at alphabetical order, the contributors to the pre-IETF QUIC project at
Google are: Britt Cyr, Jeremy Dorfman, Ryan Hamilton, Jana Iyengar, Google are: Britt Cyr, Jeremy Dorfman, Ryan Hamilton, Jana Iyengar,
Fedor Kouranov, Charles Krasic, Jo Kulik, Adam Langley, Jim Roskind, Fedor Kouranov, Charles Krasic, Jo Kulik, Adam Langley, Jim Roskind,
skipping to change at page 97, line 25 skipping to change at page 99, line 12
discussions and public ones on the quic@ietf.org and proto- discussions and public ones on the quic@ietf.org and proto-
quic@chromium.org mailing lists. Our thanks to all. quic@chromium.org mailing lists. Our thanks to all.
Appendix C. Change Log Appendix C. Change Log
*RFC Editor's Note:* Please remove this section prior to *RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document. publication of a final version of this document.
Issue and pull request numbers are listed with a leading octothorp. Issue and pull request numbers are listed with a leading octothorp.
C.1. Since draft-ietf-quic-transport-10 C.1. Since draft-ietf-quic-transport-11
o Enable server to transition connections to a preferred address
(#560, #1251)
o Packet numbers are encrypted (#1174, #1043, #1048, #1034, #850,
#990, #734, #1079)
o Packet numbers use a variable-length encoding (#989, #1334)
o STREAM frames can now be empty (#1350)
C.2. Since draft-ietf-quic-transport-10
o Swap payload length and packed number fields in long header o Swap payload length and packed number fields in long header
(#1294) (#1294)
o Clarified that CONNECTION_CLOSE is allowed in Handshake packet o Clarified that CONNECTION_CLOSE is allowed in Handshake packet
(#1274) (#1274)
o Spin bit reserved (#1283) o Spin bit reserved (#1283)
o Coalescing multiple QUIC packets in a UDP datagram (#1262, #1285) o Coalescing multiple QUIC packets in a UDP datagram (#1262, #1285)
skipping to change at page 98, line 12 skipping to change at page 100, line 12
o STOP_SENDING is now prohibited before streams are used (#1050) o STOP_SENDING is now prohibited before streams are used (#1050)
o Recommend including ACK in Retry packets and allow PADDING (#1067, o Recommend including ACK in Retry packets and allow PADDING (#1067,
#882) #882)
o Endpoints now become closing after an idle timeout (#1178, #1179) o Endpoints now become closing after an idle timeout (#1178, #1179)
o Remove implication that Version Negotiation is sent when a packet o Remove implication that Version Negotiation is sent when a packet
of the wrong version is received (#1197) of the wrong version is received (#1197)
C.2. Since draft-ietf-quic-transport-09 C.3. Since draft-ietf-quic-transport-09
o Added PATH_CHALLENGE and PATH_RESPONSE frames to replace PING with o Added PATH_CHALLENGE and PATH_RESPONSE frames to replace PING with
Data and PONG frame. Changed ACK frame type from 0x0e to 0x0d. Data and PONG frame. Changed ACK frame type from 0x0e to 0x0d.
(#1091, #725, #1086) (#1091, #725, #1086)
o A server can now only send 3 packets without validating the client o A server can now only send 3 packets without validating the client
address (#38, #1090) address (#38, #1090)
o Delivery order of stream data is no longer strongly specified o Delivery order of stream data is no longer strongly specified
(#252, #1070) (#252, #1070)
skipping to change at page 98, line 39 skipping to change at page 100, line 39
o Improved retransmission rules for all frame types: information is o Improved retransmission rules for all frame types: information is
retransmitted, not packets or frames (#463, #765, #1095, #1053) retransmitted, not packets or frames (#463, #765, #1095, #1053)
o Added an error code for server busy signals (#1137) o Added an error code for server busy signals (#1137)
o Endpoints now set the connection ID that their peer uses. o Endpoints now set the connection ID that their peer uses.
Connection IDs are variable length. Removed the Connection IDs are variable length. Removed the
omit_connection_id transport parameter and the corresponding short omit_connection_id transport parameter and the corresponding short
header flag. (#1089, #1052, #1146, #821, #745, #821, #1166, #1151) header flag. (#1089, #1052, #1146, #821, #745, #821, #1166, #1151)
C.3. Since draft-ietf-quic-transport-08 C.4. Since draft-ietf-quic-transport-08
o Clarified requirements for BLOCKED usage (#65, #924) o Clarified requirements for BLOCKED usage (#65, #924)
o BLOCKED frame now includes reason for blocking (#452, #924, #927, o BLOCKED frame now includes reason for blocking (#452, #924, #927,
#928) #928)
o GAP limitation in ACK Frame (#613) o GAP limitation in ACK Frame (#613)
o Improved PMTUD description (#614, #1036) o Improved PMTUD description (#614, #1036)
skipping to change at page 99, line 19 skipping to change at page 101, line 19
o Stateless reset clarified as version-specific (#930, #986) o Stateless reset clarified as version-specific (#930, #986)
o initial_max_stream_id_x transport parameters are optional (#970, o initial_max_stream_id_x transport parameters are optional (#970,
#971) #971)
o Ack Delay assumes a default value during the handshake (#1007, o Ack Delay assumes a default value during the handshake (#1007,
#1009) #1009)
o Removed transport parameters from NewSessionTicket (#1015) o Removed transport parameters from NewSessionTicket (#1015)
C.4. Since draft-ietf-quic-transport-07 C.5. Since draft-ietf-quic-transport-07
o The long header now has version before packet number (#926, #939) o The long header now has version before packet number (#926, #939)
o Rename and consolidate packet types (#846, #822, #847) o Rename and consolidate packet types (#846, #822, #847)
o Packet types are assigned new codepoints and the Connection ID o Packet types are assigned new codepoints and the Connection ID
Flag is inverted (#426, #956) Flag is inverted (#426, #956)
o Removed type for Version Negotiation and use Version 0 (#963, o Removed type for Version Negotiation and use Version 0 (#963,
#968) #968)
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o Address validation for connection migration (#161, #732, #878) o Address validation for connection migration (#161, #732, #878)
o Clearly defined retransmission rules for BLOCKED (#452, #65, #924) o Clearly defined retransmission rules for BLOCKED (#452, #65, #924)
o negotiated_version is sent in server transport parameters (#710, o negotiated_version is sent in server transport parameters (#710,
#959) #959)
o Increased the range over which packet numbers are randomized o Increased the range over which packet numbers are randomized
(#864, #850, #964) (#864, #850, #964)
C.5. Since draft-ietf-quic-transport-06 C.6. Since draft-ietf-quic-transport-06
o Replaced FNV-1a with AES-GCM for all "Cleartext" packets (#554) o Replaced FNV-1a with AES-GCM for all "Cleartext" packets (#554)
o Split error code space between application and transport (#485) o Split error code space between application and transport (#485)
o Stateless reset token moved to end (#820) o Stateless reset token moved to end (#820)
o 1-RTT-protected long header types removed (#848) o 1-RTT-protected long header types removed (#848)
o No acknowledgments during draining period (#852) o No acknowledgments during draining period (#852)
o Remove "application close" as a separate close type (#854) o Remove "application close" as a separate close type (#854)
o Remove timestamps from the ACK frame (#841) o Remove timestamps from the ACK frame (#841)
o Require transport parameters to only appear once (#792) o Require transport parameters to only appear once (#792)
C.6. Since draft-ietf-quic-transport-05 C.7. Since draft-ietf-quic-transport-05
o Stateless token is server-only (#726) o Stateless token is server-only (#726)
o Refactor section on connection termination (#733, #748, #328, o Refactor section on connection termination (#733, #748, #328,
#177) #177)
o Limit size of Version Negotiation packet (#585) o Limit size of Version Negotiation packet (#585)
o Clarify when and what to ack (#736) o Clarify when and what to ack (#736)
o Renamed STREAM_ID_NEEDED to STREAM_ID_BLOCKED o Renamed STREAM_ID_NEEDED to STREAM_ID_BLOCKED
o Clarify Keep-alive requirements (#729) o Clarify Keep-alive requirements (#729)
C.7. Since draft-ietf-quic-transport-04 C.8. Since draft-ietf-quic-transport-04
o Introduce STOP_SENDING frame, RST_STREAM only resets in one o Introduce STOP_SENDING frame, RST_STREAM only resets in one
direction (#165) direction (#165)
o Removed GOAWAY; application protocols are responsible for graceful o Removed GOAWAY; application protocols are responsible for graceful
shutdown (#696) shutdown (#696)
o Reduced the number of error codes (#96, #177, #184, #211) o Reduced the number of error codes (#96, #177, #184, #211)
o Version validation fields can't move or change (#121) o Version validation fields can't move or change (#121)
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o Increased the maximum length of the Largest Acknowledged field in o Increased the maximum length of the Largest Acknowledged field in
ACK frames to 64 bits (#629) ACK frames to 64 bits (#629)
o truncate_connection_id is renamed to omit_connection_id (#659) o truncate_connection_id is renamed to omit_connection_id (#659)
o CONNECTION_CLOSE terminates the connection like TCP RST (#330, o CONNECTION_CLOSE terminates the connection like TCP RST (#330,
#328) #328)
o Update labels used in HKDF-Expand-Label to match TLS 1.3 (#642) o Update labels used in HKDF-Expand-Label to match TLS 1.3 (#642)
C.8. Since draft-ietf-quic-transport-03 C.9. Since draft-ietf-quic-transport-03
o Change STREAM and RST_STREAM layout o Change STREAM and RST_STREAM layout
o Add MAX_STREAM_ID settings o Add MAX_STREAM_ID settings
C.9. Since draft-ietf-quic-transport-02 C.10. Since draft-ietf-quic-transport-02
o The size of the initial packet payload has a fixed minimum (#267, o The size of the initial packet payload has a fixed minimum (#267,
#472) #472)
o Define when Version Negotiation packets are ignored (#284, #294, o Define when Version Negotiation packets are ignored (#284, #294,
#241, #143, #474) #241, #143, #474)
o The 64-bit FNV-1a algorithm is used for integrity protection of o The 64-bit FNV-1a algorithm is used for integrity protection of
unprotected packets (#167, #480, #481, #517) unprotected packets (#167, #480, #481, #517)
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linkability (#232, #491, #496) linkability (#232, #491, #496)
o Transport parameters for 0-RTT are retained from a previous o Transport parameters for 0-RTT are retained from a previous
connection (#405, #513, #512) connection (#405, #513, #512)
* A client in 0-RTT no longer required to reset excess streams * A client in 0-RTT no longer required to reset excess streams
(#425, #479) (#425, #479)
o Expanded security considerations (#440, #444, #445, #448) o Expanded security considerations (#440, #444, #445, #448)
C.10. Since draft-ietf-quic-transport-01 C.11. Since draft-ietf-quic-transport-01
o Defined short and long packet headers (#40, #148, #361) o Defined short and long packet headers (#40, #148, #361)
o Defined a versioning scheme and stable fields (#51, #361) o Defined a versioning scheme and stable fields (#51, #361)
o Define reserved version values for "greasing" negotiation (#112, o Define reserved version values for "greasing" negotiation (#112,
#278) #278)
o The initial packet number is randomized (#35, #283) o The initial packet number is randomized (#35, #283)
skipping to change at page 104, line 36 skipping to change at page 106, line 36
o Remove error code and reason phrase from GOAWAY (#352, #355) o Remove error code and reason phrase from GOAWAY (#352, #355)
o GOAWAY includes a final stream number for both directions (#347) o GOAWAY includes a final stream number for both directions (#347)
o Error codes for RST_STREAM and CONNECTION_CLOSE are now at a o Error codes for RST_STREAM and CONNECTION_CLOSE are now at a
consistent offset (#249) consistent offset (#249)
o Defined priority as the responsibility of the application protocol o Defined priority as the responsibility of the application protocol
(#104, #303) (#104, #303)
C.11. Since draft-ietf-quic-transport-00 C.12. Since draft-ietf-quic-transport-00
o Replaced DIVERSIFICATION_NONCE flag with KEY_PHASE flag o Replaced DIVERSIFICATION_NONCE flag with KEY_PHASE flag
o Defined versioning o Defined versioning
o Reworked description of packet and frame layout o Reworked description of packet and frame layout
o Error code space is divided into regions for each component o Error code space is divided into regions for each component
o Use big endian for all numeric values o Use big endian for all numeric values
C.12. Since draft-hamilton-quic-transport-protocol-01 C.13. Since draft-hamilton-quic-transport-protocol-01
o Adopted as base for draft-ietf-quic-tls o Adopted as base for draft-ietf-quic-tls
o Updated authors/editors list o Updated authors/editors list
o Added IANA Considerations section o Added IANA Considerations section
o Moved Contributors and Acknowledgments to appendices o Moved Contributors and Acknowledgments to appendices
Authors' Addresses Authors' Addresses
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