Cryptographic Hashing in P4 Data Planes Dominik Scholz , Andreas - - PowerPoint PPT Presentation

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Cryptographic Hashing in P4 Data Planes Dominik Scholz , Andreas - - PowerPoint PPT Presentation

Mar 03, 2023 31 likes •184 views

Chair of Network Architectures and Services Department of Informatics Technical University of Munich Cryptographic Hashing in P4 Data Planes Dominik Scholz , Andreas Oeldemann, Fabien Geyer, Sebastian Gallenmller, Henning Stubbe, Thomas Wild,

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Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Cryptographic Hashing in P4 Data Planes

Dominik Scholz, Andreas Oeldemann, Fabien Geyer, Sebastian Gallenmüller, Henning Stubbe, Thomas Wild, Andreas Herkersdorf, Georg Carle Chair of Network Architectures and Services Department of Informatics Technical University of Munich

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Motivation

Manifold P4 Applications and Programs Imagine long list of P4 programs here → Few programs that require cryptographic functionality

Image from https://bit.ly/2LHVmDZ

P4 is of high interest to industry, e.g. avionics

  • Rapid prototyping
  • Program verification
  • . . .

Requires guarantees: e.g. authentication of switches

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 2

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Motivation

Cryptographic Properties and Functions

Cryptographic properties commonly found in network applications and protocols

  • Confidentiality
  • Authenticity (data/message integrity)
  • Authentication (data origin authentication)

Cryptographic functions

  • Encryption
  • Hash functions

→ in this work we focus on cryptographic hash functions

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 3

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Motivation

Use cases for cryptographic hash functions

Data structures

  • Hash maps
  • Bloom-Filter

But: cryptographic functions not required e.g. Bloom-Filter: linear-independent hashes suffice

Authenticity/Authentication

  • Message Authentication Codes
  • Client puzzles (TCP SYN cookies)

Cryptographic functions required

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 4

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Outline

Problem Statement Choice of Hash Function P4 Targets and Hash Integration Performance Results Conclusion

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 5

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Problem Statement

Feasibility of cryptographic hashing in programmable data planes

  • Hash with cryptographic properties
  • Hash of complete packet content
  • Ideally achieving 10 GbE line-rate
  • Software and hardware P4 targets

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 6

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Choice of Hash Function

Cryptography vs. Performance

Cryptographic (hash) functions are

  • Slow ↔ line-rate
  • Complex ↔ resource consumption on target

Pseudo-cryptographic SipHash

  • Optimized for small inputs
  • Optimized for performance in software

Benchmarks on software system

Hash Cycles Fixed cycles Cycles algorithm per B per packet for 64 B CRC32 0.32 0.00 10.79 Checksum 0.44 0.00 30.06 SipHash-2-4 1.06 56.40 121.10 BLAKE2b 3.14 35.85 232.77 HMAC-SHA256 5.57 959.69 1462.13

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 7

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Available P4 Targets

. . . that can be extended with cryptographic hashing

  • Software: t4p4s (P4ELTE), based on DPDK
  • Network Processing Unit: Netronome Agilio SmartNIC (NFP-4000)
  • FPGA: NetFPGA SUME (P4→NetFPGA)
  • ASIC: none that we are aware of

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 8

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P4 Hash Integration

t4p4s

  • Trivial: link library, add extern
  • Added SipHash-2-4 and HMAC-SHA512 (openssl)

NFP-4000

  • Crypto security accelerator (SHA1): not available on our card
  • Integrated SipHash-2-4 as extern in variation of C

NetFPGA SUME

  • Externs implemented in Verilog/VHDL
  • Integrated SipHash-2-4 and SHA3-512
  • Problem:
  • Data passed between P4 program and extern is a single data word
  • SDNet limit: 600 B input width
  • No timing closure due to resource congestion

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 9

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P4 Hash Integration

NetFPGA

Alternative P4 architecture model Limitations

  • All packets are always hashed
  • Hash outcome not usable in P4
  • Alternatives:
  • Hashing before P4 pipeline
  • Second P4 pipeline after hashing core
  • Traffic manager
  • SHA3-512 core uses 125 MHz → clock domain crossing

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 10

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Measurement Results

Setup

DuT LoadGen

◭ ◮ ◭ ◮

  • Load Generator
  • CBR traffic of constant packet size
  • Precise latency measurements
  • Device-under-Test (DuT)
  • Intel Xeon E5-2620 with Intel X540 NIC
  • Netronome NFP-4000 SmartNIC
  • NetFPGA SUME
  • P4 program
  • L2 forwarder
  • Hashes complete packets

Disclaimer

  • Open-source implementations
  • Non-commercial IP cores
  • Not optimized integration → proof-of-concept
  • Take performance figures with grain of salt

→ conservative numbers

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 11

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Measurement Results

Achievable Throughput

64 96 128 512 1024 1500 20 40 60 80 100 Packet Size [B] Throughput [%] t4p4s SipHash t4p4s HMAC SHA512 NetFPGA SipHash NetFPGA SHA3-512 NFP-4000 SipHash

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 12

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Measurement Results

Latency

NetFPGA

64 300 600 900 1,200 1,518 2 4 6 Packet Size [B] Latency [µs]

Baseline SHA3-512 SipHash-2-4

NFP-4000

100 101 102 103 104 50 100 Latency [log µs] Percentage

Baseline NFP-4000 5 % 80 % SipHash-2-4 NFP-4000 5 % 80 %

Stable latency: no long-tail

t4p4s

Typical behavior of software system/DPDK: long-tail

100 101 102 103 104 50 100 Latency [log µs] Percentage

Baseline DPDK 5 % 80 % SipHash DPDK 5 % 80 % Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 13

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Measurement Results

Resource Utilization

Does the program fit on the target?

  • t4p4s: trivial
  • NFP-4000: no restrictions enountered
  • NetFPGA:

LUTs Registers BRAM Abs. % Abs. %

  • Abs. [kB]

% Baseline 64,533 14.90 109,783 12.67 16,362 30.92 SipHash-2-4 66,380 15.32 114,282 13.19 17,460 32.99 SHA3-512 73,449 16.95 118,689 13.70 17,460 32.99

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 14

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Conclusion

The current use of hash functions in P4 programs

  • Data structures might be vulnerable to attacks (hash collisions)
  • Lack of programs/protocols requiring authentication and integrity

→ Cryptographic hash functions increase applicability of P4

Cryptographic hashing is target, algorithm and use-case dependent

  • Line-rate possible on hardware targets
  • Integration for instance by adjusting P4 architecture model
  • Algorithms might be better on one target than another

→ no one-size-fits-all solution → P4 specification should recommend family of hash functions, including cryptographic ones

Scholz, Oeldemann, Geyer, Gallenmüller, Stubbe, Wild, Herkersdorf, Carle — Cryptographic Hashing in P4 Data Planes 15