traefik/vendor/github.com/uber/jaeger-client-go/utils/localip.go

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2018-01-10 16:48:04 +00:00
// Copyright (c) 2016 Uber Technologies, Inc.
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package utils
import (
"errors"
"net"
)
// This code is borrowed from https://github.com/uber/tchannel-go/blob/dev/localip.go
// scoreAddr scores how likely the given addr is to be a remote address and returns the
// IP to use when listening. Any address which receives a negative score should not be used.
// Scores are calculated as:
// -1 for any unknown IP addresses.
// +300 for IPv4 addresses
// +100 for non-local addresses, extra +100 for "up" interaces.
func scoreAddr(iface net.Interface, addr net.Addr) (int, net.IP) {
var ip net.IP
if netAddr, ok := addr.(*net.IPNet); ok {
ip = netAddr.IP
} else if netIP, ok := addr.(*net.IPAddr); ok {
ip = netIP.IP
} else {
return -1, nil
}
var score int
if ip.To4() != nil {
score += 300
}
if iface.Flags&net.FlagLoopback == 0 && !ip.IsLoopback() {
score += 100
if iface.Flags&net.FlagUp != 0 {
score += 100
}
}
return score, ip
}
// HostIP tries to find an IP that can be used by other machines to reach this machine.
func HostIP() (net.IP, error) {
interfaces, err := net.Interfaces()
if err != nil {
return nil, err
}
bestScore := -1
var bestIP net.IP
// Select the highest scoring IP as the best IP.
for _, iface := range interfaces {
addrs, err := iface.Addrs()
if err != nil {
// Skip this interface if there is an error.
continue
}
for _, addr := range addrs {
score, ip := scoreAddr(iface, addr)
if score > bestScore {
bestScore = score
bestIP = ip
}
}
}
if bestScore == -1 {
return nil, errors.New("no addresses to listen on")
}
return bestIP, nil
}