Godeps/_workspace/src/github.com/jackpal/gateway/gateway_darwin.go


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package gateway

import (
    "bytes"
    "io/ioutil"
    "net"
    "os/exec"
)

func DiscoverGateway() (ip net.IP, err error) {
    routeCmd := exec.Command("route", "-n", "get", "0.0.0.0")
    stdOut, err := routeCmd.StdoutPipe()
    if err != nil {
        return
    }
    if err = routeCmd.Start(); err != nil {
        return
    }
    output, err := ioutil.ReadAll(stdOut)
    if err != nil {
        return
    }

    // Darwin route out format is always like this:
    //    route to: default
    // destination: default
    //        mask: default
    //     gateway: 192.168.1.1
    outputLines := bytes.Split(output, []byte("\n"))
    for _, line := range outputLines {
        if bytes.Contains(line, []byte("gateway:")) {
            gatewayFields := bytes.Fields(line)
            ip = net.ParseIP(string(gatewayFields[1]))
            break
        }
    }

    err = routeCmd.Wait()
    return
}