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What is nova-net?

A general-purpose reliable UDP networking library. C99 handles the hot path (serialization, send/recv, ack processing, crypto). Haskell handles the protocol logic (connection state machines, congestion control, replication). Successor to gbnet-hs.

• C99 hot path — packet serialization, CRC32C (hardware-accelerated), ChaCha20-Poly1305 AEAD, ring buffers, fragmentation, message batching. Zero heap allocation on the hot path.
• Haskell protocol brain — connection state machines, handshake orchestration, congestion control, replication. Pure, testable, correct-by-construction.
• Unsafe FFI boundary — flat scalar arguments, no Storable marshalling. Just a function pointer jump.
• Any platform — C99 core compiles everywhere. Link from Haskell, Swift, Kotlin, Python, Zig, anything.
• Effect abstraction — MonadNetwork typeclass enables pure deterministic testing with no real sockets.
• Zero external crypto deps — ChaCha20-Poly1305 implemented from scratch (RFC 8439). CRC32C with SSE4.2/ARMv8 hardware acceleration and software fallback.

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Architecture

┌─────────────────────────────────────────────┐
│           User Application                  │
├─────────────────────────────────────────────┤
│  Haskell Protocol Brain (38 modules)        │
│  Peer, Connection, Channel, Reliability,    │
│  Congestion, Handshake, Migration,          │
│  Replication, TestNet, Simulator            │
├─────────────────────────────────────────────┤
│  FFI Boundary (unsafe ccall, flat args)     │
│  NovaNet.FFI.{Packet,CRC32C,Seq,...}        │
├─────────────────────────────────────────────┤
│  C99 Hot Path (13 modules)                  │
│  nn_packet  nn_crc32c  nn_seq  nn_rtt       │
│  nn_fragment  nn_batch  nn_crypto           │
│  nn_bandwidth  nn_congestion                │
│  nn_ack_process  nn_siphash  nn_random      │
│  nn_wire  nn_ffi                            │
└─────────────────────────────────────────────┘

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C99 Modules

Module	Purpose
nn_wire.h	Little-endian helpers, byte swap, buffer bounds (header-only)
nn_packet	9-byte packet header (68-bit wire format, 8 packet types)
nn_crc32c	CRC32C integrity — SSE4.2, ARMv8 CRC hardware accel, software fallback
nn_seq	Sequence numbers (wraparound-safe), 256-entry ring buffers, ACK bitfield, loss window
nn_rtt	Jacobson/Karels RTT estimation (RFC 6298)
nn_ack_process	ACK bitfield processing against sent buffer and loss window
nn_congestion	Dual-layer: AIMD bandwidth + CWND packet window
nn_fragment	Fragment header (6 bytes LE), message splitting
nn_batch	Message batching/unbatching (count + length-prefixed)
nn_crypto	ChaCha20-Poly1305 AEAD (RFC 8439, from scratch, constant-time tag comparison)
nn_bandwidth	Sliding window bandwidth tracker
nn_siphash	SipHash-2-4 for HMAC cookies
nn_random	OS CSPRNG (getentropy/arc4random_buf/BCryptGenRandom)
nn_ffi	Flat-argument FFI entry points for Haskell

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Features

• 68-bit packet headers (4-bit type + 16-bit seq + 16-bit ack + 32-bit ack bitfield)
• 5 delivery modes (Unreliable, UnreliableSequenced, ReliableUnordered, ReliableOrdered, ReliableSequenced)
• Dual-layer congestion control (binary mode + TCP New Reno window)
• ChaCha20-Poly1305 AEAD encryption with anti-replay nonce tracking
• Hardware-accelerated CRC32C (SSE4.2 on x86, ARMv8 CRC on aarch64)
• Jacobson/Karels RTT estimation with adaptive retransmit
• Large message fragmentation and reassembly
• Connection migration
• Delta compression, interest filtering, priority accumulation, snapshot interpolation
• All multi-byte wire fields are little-endian

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Status

Feature complete. Builds clean with -Werror on Linux, macOS, and Windows.

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Build & Test

Requires GHCup with GHC >= 9.8.

cabal build                              # Build library
cabal test                               # Run all tests
cabal build --ghc-options="-Werror"      # Warnings as errors
cabal bench                              # Run benchmarks

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Contributing

cabal test && cabal build --ghc-options="-Werror"

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_{BSD-3-Clause · Novavero AI}