A Path Layer for the Internet

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1 A Path Layer for the Internet Enabling Network Operations on Encrypted Traffic Mirja Kühlewind, Tobias Bühler, Brian Trammell, ETH Zürich Stephan Neuhaus, Roman Müntener, Zürich Univ. of Applied Sciences and Gorry Fairhurst, Univ. of Aberdeen IEEE/IFIP Conf. on Network and Service Management Tokyo, 28 November 2017 measurement architecture experimentation This project has received funding from the European Union s Horizon 2020 research and innovation programme under grant agreement No The opinions expressed and arguments employed reflect only the authors' view. The European Commission is not responsible for any use that may be made of that information.. Supported by the Swiss State Secretariat for Education, Research and Innovation under contract number The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.

2 Increasing Deployment of Encryption architecture 2

3 Increasing Deployment of Encryption architecture % of Mozilla pageloads using TLS 2

4 Increasing Deployment of Encryption architecture % of Mozilla pageloads using TLS 2

5 Increasing Deployment of Encryption architecture % of Mozilla pageloads using TLS No management function that needs cleartext access to application headers/payload will work on the new Internet. 2

6 Protocol Stack Encryption QUIC share of egress traffic at Google (MAPRG, IETF99) QUIC: new, UDP-encapsulated transport, optimized for HTTP/2 Developed/deployed by Google, 7% of Internet traffic end Under standardization in the IETF, expected deployments QUIC encrypts everything not needed to establish communication and forward packets. Nothing that uses TCP headers will work on the new Internet, either. 3

7 Protocol Stack Encryption QUIC share of egress traffic at Google (MAPRG, IETF99) QUIC: new, UDP-encapsulated transport, optimized for HTTP/2 Developed/deployed by Google, 7% of Internet traffic end Under standardization in the IETF, expected deployments QUIC encrypts everything not needed to establish communication and forward packets. Nothing that uses TCP headers will work on the new Internet, either. 3

8 Explicit Cooperation The cleartext party is over, and DPI is dead. Encryption for privacy, security, and protocol evolvability. A third way: replace use of cleartext by in-network functions with endpoint-controlled signaling. Explicit cooperation based on declarative, advisory signals requiring no trust between endpoints and path can reduce disruption driven by increased encryption. 4

9 Introducing the Path Layer The boundary between network (hop-by-hop, stateless) and transport (end-to-end, stateful) blurred by in-network state. Approach: add a layer to the stack to support these functions and use crypto to reinforce the boundary. Application (higher-level semantics) Transport (end to end streams/messages) Network (hop by hop forwarding) Link (medium access) 5

10 Introducing the Path Layer The boundary between network (hop-by-hop, stateless) and transport (end-to-end, stateful) blurred by in-network state. Approach: add a layer to the stack to support these functions and use crypto to reinforce the boundary. Path Application (higher-level semantics) Transport (end to end streams/messages) Integrity and Confidentiality Protection (Privacy, Security, and Evolvability) Path Communication (Explicit Cooperation with On-Path Devices) UDP Encapsulation (NAT/middlebox Compatibility) Network (hop by hop forwarding) Link (medium access) 5

11 Path Layer Principles An endpoint should be able to explicitly expose signals to be used by onpath devices. Everything not intended for use by the path should be encrypted. An endpoint should be able to request signals from devices on the path. An on-path device should not be able to forge, change, or remove a signal sent by an endpoint. The endpoint should control signaling between endpoints and the path, or from one on-path device to another. It should be possible for an endpoint to request and receive signals from a previously unknown on-path device. The mechanism should present no significant surface for amplification attacks. 6

12 Applications of the Path Layer Transport-Independent On-Path State Latency Measurement Loss and Congestion Measurement Path Trace Accumulation Loss/Latency Tradeoff Path MTU Discovery }Today's talk Generic mechanism allows for future extensibility 7

13 Sender to Path Signaling sender on-path receiver 8

14 Sender to Path Signaling application transport path type value encrypt MAC IP sender on-path receiver 8

15 Sender to Path Signaling application transport path type value encrypt MAC IP sender on-path receiver signal type := value 8

16 Sender to Path Signaling application transport path type value encrypt MAC IP sender on-path receiver 8

17 Sender to Path Signaling application transport path type value encrypt MAC IP sender on-path receiver signal type == value 8

18 Sender to Path Signaling application transport path type value encrypt MAC IP sender on-path receiver 8

19 Sender to Path Signaling application transport path type value encrypt MAC IP sender on-path receiver MAC OK 8

20 Sender to Path Signaling application transport path type value encrypt MAC IP sender on-path receiver 8

21 Basic PLUS Header UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum 8 12 PLUS Magic 0xd8007ff Connection and Association Token (CAT) L R S Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

22 Basic PLUS Header Recognize 31 PLUS packets 0 on path UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum 8 12 PLUS Magic 0xd8007ff Connection and Association Token (CAT) L R S Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

23 Basic PLUS Header UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum 8 Connection 12 state establishment setup PLUS Magic 0xd8007ff Connection and Association Token (CAT) L R S Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

24 Basic PLUS Header UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum 8 PLUS Magic 0xd8007ff L R S 0 12 Connection and Association Token (CAT) Explicit stop signal teardown 20 Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

25 Basic PLUS Header UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum 8 12 PLUS Magic 0xd8007ff Connection and Association Token (CAT) L R S Loss 28 and latency measurement Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

26 Basic PLUS Header 31 Transport prefers 0 0 UDP Source Port loss to latency UDP Destination Port 4 UDP Length UDP Checksum 8 12 PLUS Magic 0xd8007ff Connection and Association Token (CAT) L R S Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

27 Basic PLUS Header Transport is reordering-tolerant 0 0 UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum 8 12 PLUS Magic 0xd8007ff Connection and Association Token (CAT) L R S Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

28 Basic PLUS Header UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum 8 12 PLUS Magic 0xd8007ff Connection and Association Token (CAT) L R S Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted 9

29 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

30 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

31 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

32 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

33 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

34 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

35 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

36 Transport-Independent On-Path State architecture packet a b zero uniflow stopping timeout idle timeout b a CATb = CATb stopping associating y x Sy=1 PSEy = PSNx stopwait associated timeout associated a b CATa = CATb PSEa = PSNb x y Sx = 1 10

37 Latency Measurement Sender Receiver PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

38 Latency Measurement Sender Receiver PSN n PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

39 Latency Measurement Sender Receiver PSN n RTT PSN q PSE n PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

40 Latency Measurement Sender Receiver PSN n RTT delay PSN q PSE n PSN n+1 PSE q PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

41 Latency Measurement Sender Receiver PSN n RTT delay PSN q PSE n PSN n+1 PSE q Observer PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

42 Latency Measurement Sender Receiver PSN n RTT delay PSN q PSE n RTTfwd PSN n+1 PSE q Observer PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

43 Latency Measurement Sender Receiver PSN n RTT delay PSN q PSE n RTTfwd PSN n+1 PSE q RTTrev Observer PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

44 Latency Measurement Sender Receiver PSN n RTT RTTfwd PSN q PSE n RTTest delay PSN n+1 PSE q RTTrev = RTTfwd + RTTrev Observer PSN/PSE are explicit measurement signals replacing TCP SEQ/ACK + TSOPT 11

45 Path to Receiver Signaling with Feedback sender on-path receiver 12

46 Path to Receiver Signaling with Feedback application transport path type value encrypt partial MAC IP sender on-path receiver 12

47 Path to Receiver Signaling with Feedback application transport path type value encrypt partial MAC IP sender on-path receiver signal type := value 12

48 Path to Receiver Signaling with Feedback application transport path type value encrypt partial MAC IP sender on-path receiver 12

49 Path to Receiver Signaling with Feedback application transport path type value encrypt partial MAC IP sender on-path receiver signal type := value 12

50 Path to Receiver Signaling with Feedback application transport path type value encrypt partial MAC IP sender on-path receiver 12

51 Path to Receiver Signaling with Feedback application transport path type value encrypt partial MAC IP sender on-path receiver signal type == value MAC OK 12

52 Path to Receiver Signaling with Feedback application transport fb type=value encrypt path IP sender on-path receiver 12

53 Path to Receiver Signaling with Feedback application transport fb type=value encrypt path IP sender on-path receiver 12

54 Extended PLUS Header UDP Source Port UDP Destination Port 4 UDP Length UDP Checksum PLUS Magic 0xd8007ff Connection and Association Token (CAT) Packet Serial Number (PSN) Packet Serial Echo (PSE) L R S 1 28 PCF Type PCF Len II PCF Value (varlen) Encrypted 13

55 Extended PLUS Header Extensible 12 signal type UDP Source Port UDP Length PLUS Magic 0xd8007ff UDP Destination Port UDP Checksum Connection and Association Token (CAT) 28 PCF Type PCF Len II Packet Serial Number (PSN) Packet Serial Echo (PSE) Encrypted PCF Value (varlen) L R S 1 13

56 Extended PLUS Header Extensible 12 signal type UDP Source Port UDP Length UDP Destination Port UDP Checksum PLUS Magic 0xd8007ff TLV supports Connection unknown signal and Association Token (CAT) handling Packet Serial Number (PSN) 28 PCF Type PCF Len II Packet Serial Echo (PSE) Encrypted PCF Value (varlen) L R S 1 13

57 Extended PLUS Header Extensible 12 signal type UDP Source Port UDP Destination Port Integrity Indicator UDP Length specifies UDP Checksum which portion of the PLUS Magic 0xd8007ff PCF Value is covered L R Sby 1 the TLV supports partial MAC Connection unknown signal and Association Token (CAT) handling Packet Serial Number (PSN) 28 PCF Type PCF Len II Packet Serial Echo (PSE) Encrypted PCF Value (varlen) 13

58 Extended PLUS Header Extensible 12 signal type UDP Source Port UDP Destination Port Integrity Indicator UDP Length specifies UDP Checksum which portion of the PLUS Magic 0xd8007ff PCF Value is covered L R Sby 1 the TLV supports partial MAC Connection unknown signal and Association Token (CAT) handling Variable-length value, Packet Serial Number (PSN) semantics defined by Packet Serial Echo (PSE) signal type 28 PCF Type PCF Len II Encrypted PCF Value (varlen) 13

59 Loss and Congestion Measurement PSN is serial, so sequence gaps can be used to estimate one-point upstream loss and loss between two points. Full-path loss requires signaling using extended header: PCF type: 1 len:[2,4,8,16] II: 11(full) Cumulative Loss Count (uint[8,16,32,64]) Cumulative ECE Count (uint[8,16,32,64]) Feed-forward of cumulative loss and ECE seen by sender allows accurate counting anywhere along the path. Sender-side sampling allows efficiency tradeoff. 14

60 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. 15

61 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. 15

62 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. Red path:

63 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. Red path:

64 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. Red path: 1207 Orange path:

65 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. Red path: 1207 Orange path:

66 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. Red path: 1207 Orange path: 238 Green path:

67 Path Tracing sender receiver Each PLUS-aware hop XORs random value per node to PCF type 4 value. Value at receiver indicates which path was taken without identifying path. Red path: 1207 Orange path: 238 Green path:

68 Transport interfaces to PLUS: pilot implementation work under QUIC architecture handshake handshake security (TLS+QUIC packet protection) verify error packet protected packet + pseudoheader packet transport layer (QUIC) receive signal path layer (PLUS) UDP/IP (via socket) feedback request security (TLS+QUIC packet protection) packet + pseudoheader (AD) protected packet packet transport layer (QUIC) send signal path layer (PLUS) UDP/IP (via socket) MTU (a) receiver-side interfaces (b) sender-side interfaces 16

69 Transport interfaces to PLUS: pilot implementation work under QUIC architecture handshake handshake security (TLS+QUIC packet protection) verify error packet protected packet + pseudoheader packet transport layer (QUIC) receive signal path layer (PLUS) UDP/IP (via socket) feedback request security (TLS+QUIC packet protection) packet + pseudoheader (AD) protected packet packet transport layer (QUIC) send signal path layer (PLUS) UDP/IP (via socket) MTU (a) receiver-side interfaces (b) sender-side interfaces 16

70 Transport interfaces to PLUS: pilot implementation work under QUIC architecture handshake handshake security (TLS+QUIC packet protection) verify error packet protected packet + pseudoheader packet transport layer (QUIC) receive signal path layer (PLUS) UDP/IP (via socket) feedback request security (TLS+QUIC packet protection) packet + pseudoheader (AD) protected packet packet transport layer (QUIC) send signal path layer (PLUS) UDP/IP (via socket) MTU (a) receiver-side interfaces (b) sender-side interfaces 16

71 Transport interfaces to PLUS: pilot implementation work under QUIC architecture handshake handshake security (TLS+QUIC packet protection) verify error packet protected packet + pseudoheader packet transport layer (QUIC) receive signal path layer (PLUS) UDP/IP (via socket) feedback request security (TLS+QUIC packet protection) packet + pseudoheader (AD) protected packet packet transport layer (QUIC) send signal path layer (PLUS) UDP/IP (via socket) MTU (a) receiver-side interfaces (b) sender-side interfaces 16

72 Transport interfaces to PLUS: pilot implementation work under QUIC architecture handshake handshake security (TLS+QUIC packet protection) verify error packet protected packet + pseudoheader packet transport layer (QUIC) receive signal path layer (PLUS) UDP/IP (via socket) feedback request security (TLS+QUIC packet protection) packet + pseudoheader (AD) protected packet packet transport layer (QUIC) send signal path layer (PLUS) UDP/IP (via socket) MTU (a) receiver-side interfaces (b) sender-side interfaces 16

73 Transport interfaces to PLUS: pilot implementation work under QUIC architecture handshake handshake security (TLS+QUIC packet protection) verify error packet protected packet + pseudoheader packet transport layer (QUIC) receive signal path layer (PLUS) UDP/IP (via socket) feedback request security (TLS+QUIC packet protection) packet + pseudoheader (AD) protected packet packet transport layer (QUIC) send signal path layer (PLUS) UDP/IP (via socket) MTU (a) receiver-side interfaces (b) sender-side interfaces 16

74 Building PLUS-aware middleboxes with fd.io VPP fd.io VPP: framework for building userspace network devices on any DPDK platform, using packet vectors for scalability. PLUS middlebox support implemented as VPP nodes Core node handles state machine and basic header flags One extension node per PCF type Modifications to UDP logic to recognize PLUS magic DPDK input IPv4 input IPv4 lookup IPv4 local IPv4/UDP lookup PLUS basic header PCF additional nodes output 17

75 PLUS and QUIC Both PLUS and QUIC propose encryption and UDP encapsulation to enable transport evolution. PLUS proposes additional explicit signaling to replace information that encryption removes. Declarative and advisory, but better than inference. Many basic PLUS features appear in QUIC in diminished form: QUIC's PN is a PSN, but without echo QUIC's CID is a CAT, but not on every packet Additional QUIC features proposed based on PLUS experience: No PSE, but latency spin bit proposed to replace it for passive RTT 18

76 Conclusions Adding a path layer to the Internet architecture to enable explicit cooperation between endpoints and middleboxes can support transport protocol evolution while replacing manageability and measurability lost through encryption. PLUS provides a testbed for experimenting with explicit cooperation approaches. 19

The Impact of Transport Header Encryption on Operation and Evolution of the Internet

The Impact of Transport Header Encryption on Operation and Evolution of the Internet draft-fairhurst-tsvwg-transport-encrypt Gorry Fairhurst University of Aberdeen (MAMI) Colin Perkins University of Glasgow