package overlay import ( "fmt" "math" "net" "runtime" "strconv" "github.com/slackhq/nebula/cidr" "github.com/slackhq/nebula/config" "github.com/slackhq/nebula/iputil" ) type Route struct { MTU int Metric int Cidr *net.IPNet Via *iputil.VpnIp } func makeRouteTree(routes []Route, allowMTU bool) (*cidr.Tree4, error) { routeTree := cidr.NewTree4() for _, r := range routes { if !allowMTU && r.MTU > 0 { return nil, fmt.Errorf("route MTU is not supported in %s", runtime.GOOS) } if r.Via != nil { routeTree.AddCIDR(r.Cidr, *r.Via) } } return routeTree, nil } func parseRoutes(c *config.C, network *net.IPNet) ([]Route, error) { var err error r := c.Get("tun.routes") if r == nil { return []Route{}, nil } rawRoutes, ok := r.([]interface{}) if !ok { return nil, fmt.Errorf("tun.routes is not an array") } if len(rawRoutes) < 1 { return []Route{}, nil } routes := make([]Route, len(rawRoutes)) for i, r := range rawRoutes { m, ok := r.(map[interface{}]interface{}) if !ok { return nil, fmt.Errorf("entry %v in tun.routes is invalid", i+1) } rMtu, ok := m["mtu"] if !ok { return nil, fmt.Errorf("entry %v.mtu in tun.routes is not present", i+1) } mtu, ok := rMtu.(int) if !ok { mtu, err = strconv.Atoi(rMtu.(string)) if err != nil { return nil, fmt.Errorf("entry %v.mtu in tun.routes is not an integer: %v", i+1, err) } } if mtu < 500 { return nil, fmt.Errorf("entry %v.mtu in tun.routes is below 500: %v", i+1, mtu) } rRoute, ok := m["route"] if !ok { return nil, fmt.Errorf("entry %v.route in tun.routes is not present", i+1) } r := Route{ MTU: mtu, } _, r.Cidr, err = net.ParseCIDR(fmt.Sprintf("%v", rRoute)) if err != nil { return nil, fmt.Errorf("entry %v.route in tun.routes failed to parse: %v", i+1, err) } if !ipWithin(network, r.Cidr) { return nil, fmt.Errorf( "entry %v.route in tun.routes is not contained within the network attached to the certificate; route: %v, network: %v", i+1, r.Cidr.String(), network.String(), ) } routes[i] = r } return routes, nil } func parseUnsafeRoutes(c *config.C, network *net.IPNet) ([]Route, error) { var err error r := c.Get("tun.unsafe_routes") if r == nil { return []Route{}, nil } rawRoutes, ok := r.([]interface{}) if !ok { return nil, fmt.Errorf("tun.unsafe_routes is not an array") } if len(rawRoutes) < 1 { return []Route{}, nil } routes := make([]Route, len(rawRoutes)) for i, r := range rawRoutes { m, ok := r.(map[interface{}]interface{}) if !ok { return nil, fmt.Errorf("entry %v in tun.unsafe_routes is invalid", i+1) } rMtu, ok := m["mtu"] if !ok { rMtu = c.GetInt("tun.mtu", DefaultMTU) } mtu, ok := rMtu.(int) if !ok { mtu, err = strconv.Atoi(rMtu.(string)) if err != nil { return nil, fmt.Errorf("entry %v.mtu in tun.unsafe_routes is not an integer: %v", i+1, err) } } if mtu < 500 { return nil, fmt.Errorf("entry %v.mtu in tun.unsafe_routes is below 500: %v", i+1, mtu) } rMetric, ok := m["metric"] if !ok { rMetric = 0 } metric, ok := rMetric.(int) if !ok { _, err = strconv.ParseInt(rMetric.(string), 10, 32) if err != nil { return nil, fmt.Errorf("entry %v.metric in tun.unsafe_routes is not an integer: %v", i+1, err) } } if metric < 0 || metric > math.MaxInt32 { return nil, fmt.Errorf("entry %v.metric in tun.unsafe_routes is not in range (0-%d) : %v", i+1, math.MaxInt32, metric) } rVia, ok := m["via"] if !ok { return nil, fmt.Errorf("entry %v.via in tun.unsafe_routes is not present", i+1) } via, ok := rVia.(string) if !ok { return nil, fmt.Errorf("entry %v.via in tun.unsafe_routes is not a string: found %T", i+1, rVia) } nVia := net.ParseIP(via) if nVia == nil { return nil, fmt.Errorf("entry %v.via in tun.unsafe_routes failed to parse address: %v", i+1, via) } rRoute, ok := m["route"] if !ok { return nil, fmt.Errorf("entry %v.route in tun.unsafe_routes is not present", i+1) } viaVpnIp := iputil.Ip2VpnIp(nVia) r := Route{ Via: &viaVpnIp, MTU: mtu, Metric: metric, } _, r.Cidr, err = net.ParseCIDR(fmt.Sprintf("%v", rRoute)) if err != nil { return nil, fmt.Errorf("entry %v.route in tun.unsafe_routes failed to parse: %v", i+1, err) } if ipWithin(network, r.Cidr) { return nil, fmt.Errorf( "entry %v.route in tun.unsafe_routes is contained within the network attached to the certificate; route: %v, network: %v", i+1, r.Cidr.String(), network.String(), ) } routes[i] = r } return routes, nil } func ipWithin(o *net.IPNet, i *net.IPNet) bool { // Make sure o contains the lowest form of i if !o.Contains(i.IP.Mask(i.Mask)) { return false } // Find the max ip in i ip4 := i.IP.To4() if ip4 == nil { return false } last := make(net.IP, len(ip4)) copy(last, ip4) for x := range ip4 { last[x] |= ^i.Mask[x] } // Make sure o contains the max if !o.Contains(last) { return false } return true }