mirror of https://go.googlesource.com/go
55 lines
993 B
Go
55 lines
993 B
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"internal/syscall/unix"
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"syscall"
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)
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// Linux stores the backlog as:
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//
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// - uint16 in kernel version < 4.1,
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// - uint32 in kernel version >= 4.1
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//
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// Truncate number to avoid wrapping.
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//
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// See issue 5030 and 41470.
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func maxAckBacklog(n int) int {
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major, minor := unix.KernelVersion()
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size := 16
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if major > 4 || (major == 4 && minor >= 1) {
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size = 32
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}
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var max uint = 1<<size - 1
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if uint(n) > max {
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n = int(max)
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}
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return n
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}
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func maxListenerBacklog() int {
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fd, err := open("/proc/sys/net/core/somaxconn")
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if err != nil {
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return syscall.SOMAXCONN
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}
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defer fd.close()
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l, ok := fd.readLine()
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if !ok {
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return syscall.SOMAXCONN
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}
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f := getFields(l)
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n, _, ok := dtoi(f[0])
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if n == 0 || !ok {
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return syscall.SOMAXCONN
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}
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if n > 1<<16-1 {
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return maxAckBacklog(n)
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}
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return n
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}
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