mirror of
https://github.com/k3s-io/k3s.git
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83 lines
2.5 KiB
Go
83 lines
2.5 KiB
Go
// Copyright 2015 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package netutil
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import (
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"fmt"
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"os/exec"
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)
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// DropPort drops all tcp packets that are received from the given port and sent to the given port.
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func DropPort(port int) error {
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cmdStr := fmt.Sprintf("sudo iptables -A OUTPUT -p tcp --destination-port %d -j DROP", port)
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if _, err := exec.Command("/bin/sh", "-c", cmdStr).Output(); err != nil {
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return err
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}
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cmdStr = fmt.Sprintf("sudo iptables -A INPUT -p tcp --destination-port %d -j DROP", port)
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_, err := exec.Command("/bin/sh", "-c", cmdStr).Output()
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return err
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}
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// RecoverPort stops dropping tcp packets at given port.
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func RecoverPort(port int) error {
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cmdStr := fmt.Sprintf("sudo iptables -D OUTPUT -p tcp --destination-port %d -j DROP", port)
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if _, err := exec.Command("/bin/sh", "-c", cmdStr).Output(); err != nil {
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return err
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}
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cmdStr = fmt.Sprintf("sudo iptables -D INPUT -p tcp --destination-port %d -j DROP", port)
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_, err := exec.Command("/bin/sh", "-c", cmdStr).Output()
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return err
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}
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// SetLatency adds latency in millisecond scale with random variations.
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func SetLatency(ms, rv int) error {
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ifces, err := GetDefaultInterfaces()
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if err != nil {
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return err
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}
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if rv > ms {
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rv = 1
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}
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for ifce := range ifces {
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cmdStr := fmt.Sprintf("sudo tc qdisc add dev %s root netem delay %dms %dms distribution normal", ifce, ms, rv)
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_, err = exec.Command("/bin/sh", "-c", cmdStr).Output()
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if err != nil {
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// the rule has already been added. Overwrite it.
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cmdStr = fmt.Sprintf("sudo tc qdisc change dev %s root netem delay %dms %dms distribution normal", ifce, ms, rv)
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_, err = exec.Command("/bin/sh", "-c", cmdStr).Output()
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if err != nil {
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return err
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}
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}
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}
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return nil
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}
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// RemoveLatency resets latency configurations.
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func RemoveLatency() error {
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ifces, err := GetDefaultInterfaces()
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if err != nil {
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return err
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}
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for ifce := range ifces {
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_, err = exec.Command("/bin/sh", "-c", fmt.Sprintf("sudo tc qdisc del dev %s root netem", ifce)).Output()
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if err != nil {
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return err
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}
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}
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return nil
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}
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