package networkdriver import ( "errors" "fmt" "net" "github.com/docker/libcontainer/netlink" ) var ( networkGetRoutesFct = netlink.NetworkGetRoutes ErrNoDefaultRoute = errors.New("no default route") ) func CheckNameserverOverlaps(nameservers []string, toCheck *net.IPNet) error { if len(nameservers) > 0 { for _, ns := range nameservers { _, nsNetwork, err := net.ParseCIDR(ns) if err != nil { return err } if NetworkOverlaps(toCheck, nsNetwork) { return ErrNetworkOverlapsWithNameservers } } } return nil } func CheckRouteOverlaps(toCheck *net.IPNet) error { networks, err := networkGetRoutesFct() if err != nil { return err } for _, network := range networks { if network.IPNet != nil && NetworkOverlaps(toCheck, network.IPNet) { return ErrNetworkOverlaps } } return nil } // Detects overlap between one IPNet and another func NetworkOverlaps(netX *net.IPNet, netY *net.IPNet) bool { if len(netX.IP) == len(netY.IP) { if firstIP, _ := NetworkRange(netX); netY.Contains(firstIP) { return true } if firstIP, _ := NetworkRange(netY); netX.Contains(firstIP) { return true } } return false } // Calculates the first and last IP addresses in an IPNet func NetworkRange(network *net.IPNet) (net.IP, net.IP) { var netIP net.IP if network.IP.To4() != nil { netIP = network.IP.To4() } else if network.IP.To16() != nil { netIP = network.IP.To16() } else { return nil, nil } lastIP := make([]byte, len(netIP), len(netIP)) for i := 0; i < len(netIP); i++ { lastIP[i] = netIP[i] | ^network.Mask[i] } return netIP.Mask(network.Mask), net.IP(lastIP) } // Return the first IPv4 address and slice of IPv6 addresses for the specified network interface func GetIfaceAddr(name string) (net.Addr, []net.Addr, error) { iface, err := net.InterfaceByName(name) if err != nil { return nil, nil, err } addrs, err := iface.Addrs() if err != nil { return nil, nil, err } var addrs4 []net.Addr var addrs6 []net.Addr for _, addr := range addrs { ip := (addr.(*net.IPNet)).IP if ip4 := ip.To4(); ip4 != nil { addrs4 = append(addrs4, addr) } else if ip6 := ip.To16(); len(ip6) == net.IPv6len { addrs6 = append(addrs6, addr) } } switch { case len(addrs4) == 0: return nil, nil, fmt.Errorf("Interface %v has no IPv4 addresses", name) case len(addrs4) > 1: fmt.Printf("Interface %v has more than 1 IPv4 address. Defaulting to using %v\n", name, (addrs4[0].(*net.IPNet)).IP) } return addrs4[0], addrs6, nil } func GetDefaultRouteIface() (*net.Interface, error) { rs, err := networkGetRoutesFct() if err != nil { return nil, fmt.Errorf("unable to get routes: %v", err) } for _, r := range rs { if r.Default { return r.Iface, nil } } return nil, ErrNoDefaultRoute }