go.etcd.io/etcd@v3.3.27+incompatible/pkg/netutil/isolate_linux.go (about)

     1  // Copyright 2015 The etcd Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package netutil
    16  
    17  import (
    18  	"fmt"
    19  	"os/exec"
    20  )
    21  
    22  // DropPort drops all tcp packets that are received from the given port and sent to the given port.
    23  func DropPort(port int) error {
    24  	cmdStr := fmt.Sprintf("sudo iptables -A OUTPUT -p tcp --destination-port %d -j DROP", port)
    25  	if _, err := exec.Command("/bin/sh", "-c", cmdStr).Output(); err != nil {
    26  		return err
    27  	}
    28  	cmdStr = fmt.Sprintf("sudo iptables -A INPUT -p tcp --destination-port %d -j DROP", port)
    29  	_, err := exec.Command("/bin/sh", "-c", cmdStr).Output()
    30  	return err
    31  }
    32  
    33  // RecoverPort stops dropping tcp packets at given port.
    34  func RecoverPort(port int) error {
    35  	cmdStr := fmt.Sprintf("sudo iptables -D OUTPUT -p tcp --destination-port %d -j DROP", port)
    36  	if _, err := exec.Command("/bin/sh", "-c", cmdStr).Output(); err != nil {
    37  		return err
    38  	}
    39  	cmdStr = fmt.Sprintf("sudo iptables -D INPUT -p tcp --destination-port %d -j DROP", port)
    40  	_, err := exec.Command("/bin/sh", "-c", cmdStr).Output()
    41  	return err
    42  }
    43  
    44  // SetLatency adds latency in millisecond scale with random variations.
    45  func SetLatency(ms, rv int) error {
    46  	ifces, err := GetDefaultInterfaces()
    47  	if err != nil {
    48  		return err
    49  	}
    50  
    51  	if rv > ms {
    52  		rv = 1
    53  	}
    54  	for ifce := range ifces {
    55  		cmdStr := fmt.Sprintf("sudo tc qdisc add dev %s root netem delay %dms %dms distribution normal", ifce, ms, rv)
    56  		_, err = exec.Command("/bin/sh", "-c", cmdStr).Output()
    57  		if err != nil {
    58  			// the rule has already been added. Overwrite it.
    59  			cmdStr = fmt.Sprintf("sudo tc qdisc change dev %s root netem delay %dms %dms distribution normal", ifce, ms, rv)
    60  			_, err = exec.Command("/bin/sh", "-c", cmdStr).Output()
    61  			if err != nil {
    62  				return err
    63  			}
    64  		}
    65  	}
    66  	return nil
    67  }
    68  
    69  // RemoveLatency resets latency configurations.
    70  func RemoveLatency() error {
    71  	ifces, err := GetDefaultInterfaces()
    72  	if err != nil {
    73  		return err
    74  	}
    75  	for ifce := range ifces {
    76  		_, err = exec.Command("/bin/sh", "-c", fmt.Sprintf("sudo tc qdisc del dev %s root netem", ifce)).Output()
    77  		if err != nil {
    78  			return err
    79  		}
    80  	}
    81  	return nil
    82  }