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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 13:14:23 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 13:14:23 +0000
commit73df946d56c74384511a194dd01dbe099584fd1a (patch)
treefd0bcea490dd81327ddfbb31e215439672c9a068 /src/net/sock_linux.go
parentInitial commit. (diff)
downloadgolang-1.16-upstream.tar.xz
golang-1.16-upstream.zip
Adding upstream version 1.16.10.upstream/1.16.10upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/net/sock_linux.go')
-rw-r--r--src/net/sock_linux.go86
1 files changed, 86 insertions, 0 deletions
diff --git a/src/net/sock_linux.go b/src/net/sock_linux.go
new file mode 100644
index 0000000..9f62ed3
--- /dev/null
+++ b/src/net/sock_linux.go
@@ -0,0 +1,86 @@
+// 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.
+
+package net
+
+import "syscall"
+
+func kernelVersion() (major int, minor int) {
+ var uname syscall.Utsname
+ if err := syscall.Uname(&uname); err != nil {
+ return
+ }
+
+ rl := uname.Release
+ var values [2]int
+ vi := 0
+ value := 0
+ for _, c := range rl {
+ if c >= '0' && c <= '9' {
+ value = (value * 10) + int(c-'0')
+ } else {
+ // Note that we're assuming N.N.N here. If we see anything else we are likely to
+ // mis-parse it.
+ values[vi] = value
+ vi++
+ if vi >= len(values) {
+ break
+ }
+ value = 0
+ }
+ }
+ switch vi {
+ case 0:
+ return 0, 0
+ case 1:
+ return values[0], 0
+ case 2:
+ return values[0], values[1]
+ }
+ return
+}
+
+// Linux stores the backlog as:
+//
+// - uint16 in kernel version < 4.1,
+// - uint32 in kernel version >= 4.1
+//
+// Truncate number to avoid wrapping.
+//
+// See issue 5030 and 41470.
+func maxAckBacklog(n int) int {
+ major, minor := kernelVersion()
+ size := 16
+ if major > 4 || (major == 4 && minor >= 1) {
+ size = 32
+ }
+
+ var max uint = 1<<size - 1
+ if uint(n) > max {
+ n = int(max)
+ }
+ return n
+}
+
+func maxListenerBacklog() int {
+ fd, err := open("/proc/sys/net/core/somaxconn")
+ if err != nil {
+ return syscall.SOMAXCONN
+ }
+ defer fd.close()
+ l, ok := fd.readLine()
+ if !ok {
+ return syscall.SOMAXCONN
+ }
+ f := getFields(l)
+ n, _, ok := dtoi(f[0])
+ if n == 0 || !ok {
+ return syscall.SOMAXCONN
+ }
+
+ if n > 1<<16-1 {
+ return maxAckBacklog(n)
+ }
+ return n
+}