1
0
mirror of https://github.com/golang/go synced 2024-10-05 20:41:22 -06:00
go/src/pkg/net/sock_bsd.go
Russ Cox e64f3f211a net: never use backlog > 65535
The system call takes an int, but the kernel stores it in a uint16.
At least one Linux system sets /proc/sys/net/core/somaxconn
to 262144, which ends up being 0 in the uint16. Avoid being tricked.

FreeBSD sources also store the backlog in a uint16.
Assume the problem is systemic and fix it everywhere.

Fixes #5030.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7480046
2013-03-12 01:48:48 -04:00

38 lines
825 B
Go

// 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.
// +build darwin freebsd netbsd openbsd
package net
import (
"runtime"
"syscall"
)
func maxListenerBacklog() int {
var (
n uint32
err error
)
switch runtime.GOOS {
case "darwin", "freebsd":
n, err = syscall.SysctlUint32("kern.ipc.somaxconn")
case "netbsd":
// NOTE: NetBSD has no somaxconn-like kernel state so far
case "openbsd":
n, err = syscall.SysctlUint32("kern.somaxconn")
}
if n == 0 || err != nil {
return syscall.SOMAXCONN
}
// FreeBSD stores the backlog in a uint16, as does Linux.
// Assume the other BSDs do too. Truncate number to avoid wrapping.
// See issue 5030.
if n > 1<<16-1 {
n = 1<<16 - 1
}
return int(n)
}