if cfg.Idle == 0 {
		cfg.Idle = defaultTCPKeepAliveIdle
	}
	if cfg.Interval == 0 {
		cfg.Interval = defaultTCPKeepAliveInterval
	}
	if cfg.Count == 0 {
		cfg.Count = defaultTCPKeepAliveCount
	}

	if cfg.Idle == -1 {
		cfg.Idle = oldCfg.Idle
	}
	// Check out the comment on KeepAliveConfig and the illumos code:

	ver := un.Version[:]
	if runtime.GOOS == "illumos" {
		// Illumos distributions use different formats without a parsable
		// and unified pattern for the Version field while Release level
		// string is guaranteed to be in x.y or x.y.z format regardless of
		// whether the kernel is Solaris or illumos.
		ver = un.Release[:]
	}

	parseNext := func() (n int) {
		for i, c := range ver {

	// being used is extremely unlikely.
	pid := math.MaxInt32
	if runtime.GOOS == "solaris" || runtime.GOOS == "illumos" {
		// Solaris/Illumos have a lower limit, above which wait returns
		// EINVAL (see waitid in usr/src/uts/common/os/exit.c in
		// illumos). This is configurable via sysconf(_SC_MAXPID), but
		// we'll just take the default.
		pid = 30000-1
	}

	p, err := FindProcess(pid)

//   - android: see linux
//   - darwin: https://github.com/apple/darwin-xnu/blob/main/bsd/man/man2/open.2
//   - hurd: who knows if it works at all (https://www.gnu.org/software/hurd/open_issues/open_symlink.html)
//   - illumos: https://illumos.org/man/2/open
//   - ios: see darwin
//   - linux: https://man7.org/linux/man-pages/man2/openat.2.html
//   - openbsd: https://man.openbsd.org/open.2

// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build aix || dragonfly || freebsd || illumos || linux || netbsd

package net

import (
	"syscall"
	"testing"
)

const (
	syscall_TCP_KEEPIDLE  = syscall.TCP_KEEPIDLE
	syscall_TCP_KEEPCNT   = syscall.TCP_KEEPCNT
	syscall_TCP_KEEPINTVL = syscall.TCP_KEEPINTVL
)

	{"android", "arm64"},
	{"darwin", "amd64"},
	{"darwin", "arm64"},
	{"dragonfly", "amd64"},
	{"freebsd", "386"},
	{"freebsd", "amd64"},
	{"freebsd", "arm"},
	{"freebsd", "arm64"},
	{"freebsd", "riscv64"},
	{"illumos", "amd64"},
	{"ios", "amd64"},
	{"ios", "arm64"},
	{"js", "wasm"},
	{"linux", "386"},
	{"linux", "amd64"},
	{"linux", "arm"},
	{"linux", "arm64"},
	{"linux", "loong64"},
	{"linux", "mips"},

#if defined(__GLIBC__) || (defined(__sun) && !defined(__illumos__))
	// pthread_getattr_np is a GNU extension supported in glibc.
	// Solaris is not glibc but does support pthread_getattr_np
	// (and the fallback doesn't work...). Illumos does not.
	pthread_getattr_np(pthread_self(), &attr);  // GNU extension
	pthread_attr_getstack(&attr, &addr, &size); // low address
#elif defined(__illumos__)
	pthread_attr_get_np(pthread_self(), &attr);

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build aix || dragonfly || freebsd || illumos || linux || netbsd

package net

import (
	"runtime"
	"syscall"
	"time"
)

func setKeepAliveIdle(fd *netFD, d time.Duration) error {
	if d == 0 {
		d = defaultTCPKeepAliveIdle
	} else if d < 0 {
		return nil
	}

// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build aix || darwin || dragonfly || freebsd || illumos || linux || netbsd || windows

package net

import "time"

var testConfigs = []KeepAliveConfig{
	{
		Enable:   true,
		Idle:     5 * time.Second,
		Interval: 3 * time.Second,
		Count:    10,
	},
	{

// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build (!windows && !solaris) || illumos

package net

import "syscall"

// SetKeepAliveConfig configures keep-alive messages sent by the operating system.
func (c *TCPConn) SetKeepAliveConfig(config KeepAliveConfig) error {
	if !c.ok() {
		return syscall.EINVAL
	}