cmd/web/gethostip.go


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// +build dragonfly freebsd linux nacl netbsd openbsd solaris darwin

package main

import (
	"net"
)

// GetHostIP attempts to guess the IP address of the current machine and
// returns that. Simply bails at the first non sane looking IP and returns it.
// Not ideal but it should work well enough most of the time
func GetHostIP() string {
	iFaces, err := net.Interfaces()
	if err != nil {
		return "127.0.0.1"
	}

	// RFC 3927
	_, ipv4LinkLocal, _ := net.ParseCIDR("169.254.0.0/16")

	for _, iFace := range iFaces {
		addrs, err := iFace.Addrs()
		if err != nil {
			continue
		}

		for _, a := range addrs {
			n, ok := a.(*net.IPNet)
			if !ok {
				continue
			}

			if n.IP.To4() != nil && !n.IP.IsLoopback() && !ipv4LinkLocal.Contains(n.IP.To4()) {
				return n.IP.String()
			}
		}
	}

	return "127.0.0.1"
}