utils.go 2.5 KB

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  1. package networkdriver
  2. import (
  3. "errors"
  4. "fmt"
  5. "net"
  6. "github.com/docker/libcontainer/netlink"
  7. )
  8. var (
  9. networkGetRoutesFct = netlink.NetworkGetRoutes
  10. ErrNoDefaultRoute = errors.New("no default route")
  11. )
  12. func CheckNameserverOverlaps(nameservers []string, toCheck *net.IPNet) error {
  13. if len(nameservers) > 0 {
  14. for _, ns := range nameservers {
  15. _, nsNetwork, err := net.ParseCIDR(ns)
  16. if err != nil {
  17. return err
  18. }
  19. if NetworkOverlaps(toCheck, nsNetwork) {
  20. return ErrNetworkOverlapsWithNameservers
  21. }
  22. }
  23. }
  24. return nil
  25. }
  26. func CheckRouteOverlaps(toCheck *net.IPNet) error {
  27. networks, err := networkGetRoutesFct()
  28. if err != nil {
  29. return err
  30. }
  31. for _, network := range networks {
  32. if network.IPNet != nil && NetworkOverlaps(toCheck, network.IPNet) {
  33. return ErrNetworkOverlaps
  34. }
  35. }
  36. return nil
  37. }
  38. // Detects overlap between one IPNet and another
  39. func NetworkOverlaps(netX *net.IPNet, netY *net.IPNet) bool {
  40. if firstIP, _ := NetworkRange(netX); netY.Contains(firstIP) {
  41. return true
  42. }
  43. if firstIP, _ := NetworkRange(netY); netX.Contains(firstIP) {
  44. return true
  45. }
  46. return false
  47. }
  48. // Calculates the first and last IP addresses in an IPNet
  49. func NetworkRange(network *net.IPNet) (net.IP, net.IP) {
  50. var netIP net.IP
  51. if network.IP.To4() != nil {
  52. netIP = network.IP.To4()
  53. } else if network.IP.To16() != nil {
  54. netIP = network.IP.To16()
  55. } else {
  56. return nil, nil
  57. }
  58. lastIP := make([]byte, len(netIP), len(netIP))
  59. for i := 0; i < len(netIP); i++ {
  60. lastIP[i] = netIP[i] | ^network.Mask[i]
  61. }
  62. return netIP.Mask(network.Mask), net.IP(lastIP)
  63. }
  64. // Return the IPv4 address of a network interface
  65. func GetIfaceAddr(name string) (net.Addr, error) {
  66. iface, err := net.InterfaceByName(name)
  67. if err != nil {
  68. return nil, err
  69. }
  70. addrs, err := iface.Addrs()
  71. if err != nil {
  72. return nil, err
  73. }
  74. var addrs4 []net.Addr
  75. for _, addr := range addrs {
  76. ip := (addr.(*net.IPNet)).IP
  77. if ip4 := ip.To4(); ip4 != nil {
  78. addrs4 = append(addrs4, addr)
  79. }
  80. }
  81. switch {
  82. case len(addrs4) == 0:
  83. return nil, fmt.Errorf("Interface %v has no IP addresses", name)
  84. case len(addrs4) > 1:
  85. fmt.Printf("Interface %v has more than 1 IPv4 address. Defaulting to using %v\n",
  86. name, (addrs4[0].(*net.IPNet)).IP)
  87. }
  88. return addrs4[0], nil
  89. }
  90. func GetDefaultRouteIface() (*net.Interface, error) {
  91. rs, err := networkGetRoutesFct()
  92. if err != nil {
  93. return nil, fmt.Errorf("unable to get routes: %v", err)
  94. }
  95. for _, r := range rs {
  96. if r.Default {
  97. return r.Iface, nil
  98. }
  99. }
  100. return nil, ErrNoDefaultRoute
  101. }