/
sysctl_linux.go
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/
sysctl_linux.go
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//go:build linux
// +build linux
// Copyright 2020 Antrea Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package sysctl
import (
"os"
"path"
"strconv"
"strings"
"k8s.io/klog/v2"
)
const (
sysctlNet = "/proc/sys/net"
)
// GetSysctlNet returns the value for sysctl net.* settings
func GetSysctlNet(sysctl string) (int, error) {
data, err := os.ReadFile(path.Join(sysctlNet, sysctl))
if err != nil {
return -1, err
}
val, err := strconv.Atoi(strings.Trim(string(data), " \n"))
if err != nil {
return -1, err
}
return val, nil
}
// SetSysctlNet sets the specified sysctl net.* parameter to the new value.
func SetSysctlNet(sysctl string, newVal int) error {
// #nosec G306: provided permissions match /proc/sys file permissions
return os.WriteFile(path.Join(sysctlNet, sysctl), []byte(strconv.Itoa(newVal)), 0640)
}
// EnsureSysctlNetValue checks if the specified sysctl net.* parameter is already set to the
// provided value, and if not, it makes it so.
func EnsureSysctlNetValue(sysctl string, value int) error {
val, err := GetSysctlNet(sysctl)
if err != nil {
// If permission error, please provide access to sysctl setting
klog.Errorf("Error when getting %s: %v", sysctl, err)
return err
} else if val != value {
err = SetSysctlNet(sysctl, value)
if err != nil {
// If permission error, please provide access to sysctl setting
klog.Errorf("Error when setting %s: %v", sysctl, err)
return err
}
}
return nil
}