sock v0.2.0 — Linux socket options and UDP batch operations

[hayabusa-cloud]

Introduction

• sock provides zero-overhead, non-blocking socket primitives for high-performance network programming in Go. Built on top of zcall for direct syscall access, sock delivers TCP, UDP, SCTP, and Unix domain socket support with semantic error handling and adaptive I/O patterns.

• The package implements the Strike-Spin-Adapt model for I/O operations: direct syscalls for immediate completion, spin-waiting for short delays, and adaptive backoff for longer waits. All operations are non-blocking by default, returning iox.ErrWouldBlock when data is not immediately available.

• sock supports Linux-specific optimizations including zero-copy sends (SO_ZEROCOPY), TCP Fast Open, UDP segmentation offload (GSO/GRO), and batch message operations (sendmmsg/recvmmsg).

Usage

// TCP server with adaptive accept
ln, _ := sock.ListenTCP4(&sock.TCPAddr{IP: net.IPv4(0, 0, 0, 0), Port: 8080})
ln.SetDeadline(time.Now().Add(30 * time.Second))
conn, _ := ln.Accept()

// UDP batch operations
msgs := []sock.UDPMessage{
    {Addr: addr1, Buffers: [][]byte{data1}},
    {Addr: addr2, Buffers: [][]byte{data2}},
}
n, _ := conn.SendMessages(msgs)

// Socket options
sock.SetTCPUserTimeout(conn.FD(), 30000)
sock.SetBusyPoll(conn.FD(), 50)

Highlights

This release adds Linux-specific socket options for performance tuning and introduces UDP batch operations for high-throughput packet processing. Bug fixes improve abstract Unix socket handling and EINTR resilience.

What's Changed

Bug Fixes

• Abstract socket decoding: Correctly decode abstract Unix socket names using kernel-provided addrlen
• EINTR handling: Retry accept operations interrupted by signals
• SCTP resolution: Correct SCTP address resolution for IPv4/IPv6

Features

• Linux socket options: Add TCP_USER_TIMEOUT, TCP_NOTSENT_LOWAT, SO_BUSY_POLL, UDP GSO/GRO
• UDP batch operations: Add SendMessages/RecvMessages for sendmmsg/recvmmsg syscalls

Improvements

• Dependencies: Update iofd to v0.3.2, zcall to v0.2.2

Compatibility

• Go: 1.25+
• Platforms: Linux (amd64, arm64, riscv64, loong64)

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This discussion was created from the release sock v0.2.0 — Linux socket options and UDP batch operations.