package networkdriver import ( "encoding/binary" "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 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 = network.IP.To4() firstIP = netIP.Mask(network.Mask) lastIP = net.IPv4(0, 0, 0, 0).To4() ) for i := 0; i < len(lastIP); i++ { lastIP[i] = netIP[i] | ^network.Mask[i] } return firstIP, lastIP } // Given a netmask, calculates the number of available hosts func NetworkSize(mask net.IPMask) int32 { m := net.IPv4Mask(0, 0, 0, 0) for i := 0; i < net.IPv4len; i++ { m[i] = ^mask[i] } return int32(binary.BigEndian.Uint32(m)) + 1 } // Return the IPv4 address of a network interface func GetIfaceAddr(name string) (net.Addr, error) { iface, err := net.InterfaceByName(name) if err != nil { return nil, err } addrs, err := iface.Addrs() if err != nil { return nil, err } var addrs4 []net.Addr for _, addr := range addrs { ip := (addr.(*net.IPNet)).IP if ip4 := ip.To4(); len(ip4) == net.IPv4len { addrs4 = append(addrs4, addr) } } switch { case len(addrs4) == 0: return nil, fmt.Errorf("Interface %v has no IP 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], 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 }