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net.go
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net.go
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// Copyright 2017 Istio 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 proxy
import (
"context"
"net"
"time"
)
// Network-related utility functions
const (
waitInterval = 100 * time.Millisecond
waitTimeout = 2 * time.Minute
)
// GetPrivateIPs blocks until private IP addresses are available, or a timeout is reached.
func GetPrivateIPs(ctx context.Context) ([]string, bool) {
if _, ok := ctx.Deadline(); !ok {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, waitTimeout)
defer cancel()
}
for {
select {
case <-ctx.Done():
return getPrivateIPsIfAvailable()
default:
addr, ok := getPrivateIPsIfAvailable()
if ok {
return addr, true
}
time.Sleep(waitInterval)
}
}
}
// Returns all the private IP addresses
func getPrivateIPsIfAvailable() ([]string, bool) {
ok := true
ipAddresses := make([]string, 0)
ifaces, _ := net.Interfaces()
for _, iface := range ifaces {
if iface.Flags&net.FlagUp == 0 {
continue // interface down
}
if iface.Flags&net.FlagLoopback != 0 {
continue // loopback interface
}
addrs, _ := iface.Addrs()
for _, addr := range addrs {
var ip net.IP
switch v := addr.(type) {
case *net.IPNet:
ip = v.IP
case *net.IPAddr:
ip = v.IP
}
if ip == nil || ip.IsLoopback() {
continue
}
if ip.IsUnspecified() {
ok = false
continue
}
ipAddresses = append(ipAddresses, ip.String())
}
}
return ipAddresses, ok
}