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package libvirt
import (
"fmt"
"io/ioutil"
"math/rand"
"net"
"net/http"
"os"
"path"
"time"
)
const (
maxIfaceNum = 100
)
// RandomMACAddress returns a randomized MAC address
func RandomMACAddress() (string, error) {
buf := make([]byte, 6)
_, err := rand.Read(buf)
if err != nil {
return "", err
}
// set local bit and unicast
buf[0] = (buf[0] | 2) & 0xfe
// Set the local bit
buf[0] |= 2
// avoid libvirt-reserved addresses
if buf[0] == 0xfe {
buf[0] = 0xee
}
return fmt.Sprintf("%02x:%02x:%02x:%02x:%02x:%02x",
buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]), nil
}
// RandomPort returns a random port
func RandomPort() int {
const minPort = 1024
const maxPort = 65535
rand.Seed(time.Now().Unix())
return rand.Intn(maxPort-minPort) + minPort
}
// FreeNetworkInterface returns a free network interface
func FreeNetworkInterface(basename string) (string, error) {
for i := 0; i < maxIfaceNum; i++ {
ifaceName := fmt.Sprintf("%s%d", basename, i)
_, err := net.InterfaceByName(ifaceName)
if err != nil {
return ifaceName, nil
}
}
return "", fmt.Errorf("could not obtain a free network interface")
}
// NetworkRange calculates the first and last IP addresses in an IPNet
func NetworkRange(network *net.IPNet) (net.IP, net.IP) {
netIP := network.IP.To4()
lastIP := net.IPv4(0, 0, 0, 0).To4()
if netIP == nil {
netIP = network.IP.To16()
lastIP = net.IPv6zero.To16()
}
firstIP := netIP.Mask(network.Mask)
for i := 0; i < len(lastIP); i++ {
lastIP[i] = netIP[i] | ^network.Mask[i]
}
return firstIP, lastIP
}
// a HTTP server that serves files in a directory, used mostly for testing
type fileWebServer struct {
Dir string
Port int
URL string
server *http.Server
}
func (fws *fileWebServer) Start() error {
dir, err := ioutil.TempDir(fws.Dir, "")
if err != nil {
return err
}
fws.Dir = dir
fws.Port = RandomPort()
fws.URL = fmt.Sprintf("http://127.0.0.1:%d", fws.Port)
handler := http.NewServeMux()
handler.Handle("/", http.FileServer(http.Dir(dir)))
fws.server = &http.Server{Addr: fmt.Sprintf(":%d", fws.Port), Handler: handler}
ln, err := net.Listen("tcp", fws.server.Addr)
if err != nil {
return err
}
go fws.server.Serve(ln)
return nil
}
// Adds a file (with some content) in the directory served by the fileWebServer
func (fws *fileWebServer) AddFile(content []byte) (string, *os.File, error) {
tmpfile, err := ioutil.TempFile(fws.Dir, "file-")
if err != nil {
return "", nil, err
}
if len(content) > 0 {
if _, err := tmpfile.Write(content); err != nil {
return "", nil, err
}
}
return fmt.Sprintf("%s/%s", fws.URL, path.Base(tmpfile.Name())), tmpfile, nil
}
func (fws *fileWebServer) Stop() {
os.RemoveAll(fws.Dir)
}
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