github.com/s1s1ty/go@v0.0.0-20180207192209-104445e3140f/src/net/sock_linux.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package net
     6  
     7  import "syscall"
     8  
     9  func maxListenerBacklog() int {
    10  	fd, err := open("/proc/sys/net/core/somaxconn")
    11  	if err != nil {
    12  		return syscall.SOMAXCONN
    13  	}
    14  	defer fd.close()
    15  	l, ok := fd.readLine()
    16  	if !ok {
    17  		return syscall.SOMAXCONN
    18  	}
    19  	f := getFields(l)
    20  	n, _, ok := dtoi(f[0])
    21  	if n == 0 || !ok {
    22  		return syscall.SOMAXCONN
    23  	}
    24  	// Linux stores the backlog in a uint16.
    25  	// Truncate number to avoid wrapping.
    26  	// See issue 5030.
    27  	if n > 1<<16-1 {
    28  		n = 1<<16 - 1
    29  	}
    30  	return n
    31  }