Switch most everything to netip in prep for ipv6 in the overlay (#1173)

calculated_remote.go

@@ -1,41 +1,36 @@
 package nebula
 
 import (
+	"encoding/binary"
 	"fmt"
 	"math"
 	"net"
+	"net/netip"
 	"strconv"
 
-	"github.com/slackhq/nebula/cidr"
+	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
-	"github.com/slackhq/nebula/iputil"
 )
 
 // This allows us to "guess" what the remote might be for a host while we wait
 // for the lighthouse response. See "lighthouse.calculated_remotes" in the
 // example config file.
 type calculatedRemote struct {
-	ipNet  net.IPNet
-	maskIP iputil.VpnIp
-	mask   iputil.VpnIp
-	port   uint32
+	ipNet netip.Prefix
+	mask  netip.Prefix
+	port  uint32
 }
 
-func newCalculatedRemote(ipNet *net.IPNet, port int) (*calculatedRemote, error) {
-	// Ensure this is an IPv4 mask that we expect
-	ones, bits := ipNet.Mask.Size()
-	if ones == 0 || bits != 32 {
-		return nil, fmt.Errorf("invalid mask: %v", ipNet)
-	}
+func newCalculatedRemote(maskCidr netip.Prefix, port int) (*calculatedRemote, error) {
+	masked := maskCidr.Masked()
 	if port < 0 || port > math.MaxUint16 {
 		return nil, fmt.Errorf("invalid port: %d", port)
 	}
 
 	return &calculatedRemote{
-		ipNet:  *ipNet,
-		maskIP: iputil.Ip2VpnIp(ipNet.IP),
-		mask:   iputil.Ip2VpnIp(ipNet.Mask),
-		port:   uint32(port),
+		ipNet: maskCidr,
+		mask:  masked,
+		port:  uint32(port),
 	}, nil
 }
 
@@ -43,21 +38,41 @@ func (c *calculatedRemote) String() string {
 	return fmt.Sprintf("CalculatedRemote(mask=%v port=%d)", c.ipNet, c.port)
 }
 
-func (c *calculatedRemote) Apply(ip iputil.VpnIp) *Ip4AndPort {
+func (c *calculatedRemote) Apply(ip netip.Addr) *Ip4AndPort {
 	// Combine the masked bytes of the "mask" IP with the unmasked bytes
 	// of the overlay IP
-	masked := (c.maskIP & c.mask) | (ip & ^c.mask)
-
-	return &Ip4AndPort{Ip: uint32(masked), Port: c.port}
+	if c.ipNet.Addr().Is4() {
+		return c.apply4(ip)
+	}
+	return c.apply6(ip)
 }
 
-func NewCalculatedRemotesFromConfig(c *config.C, k string) (*cidr.Tree4[[]*calculatedRemote], error) {
+func (c *calculatedRemote) apply4(ip netip.Addr) *Ip4AndPort {
+	//TODO: IPV6-WORK this can be less crappy
+	maskb := net.CIDRMask(c.mask.Bits(), c.mask.Addr().BitLen())
+	mask := binary.BigEndian.Uint32(maskb[:])
+
+	b := c.mask.Addr().As4()
+	maskIp := binary.BigEndian.Uint32(b[:])
+
+	b = ip.As4()
+	intIp := binary.BigEndian.Uint32(b[:])
+
+	return &Ip4AndPort{(maskIp & mask) | (intIp & ^mask), c.port}
+}
+
+func (c *calculatedRemote) apply6(ip netip.Addr) *Ip4AndPort {
+	//TODO: IPV6-WORK
+	panic("Can not calculate ipv6 remote addresses")
+}
+
+func NewCalculatedRemotesFromConfig(c *config.C, k string) (*bart.Table[[]*calculatedRemote], error) {
 	value := c.Get(k)
 	if value == nil {
 		return nil, nil
 	}
 
-	calculatedRemotes := cidr.NewTree4[[]*calculatedRemote]()
+	calculatedRemotes := new(bart.Table[[]*calculatedRemote])
 
 	rawMap, ok := value.(map[any]any)
 	if !ok {
@@ -69,17 +84,18 @@ func NewCalculatedRemotesFromConfig(c *config.C, k string) (*cidr.Tree4[[]*calcu
 			return nil, fmt.Errorf("config `%s` has invalid key (type %T): %v", k, rawKey, rawKey)
 		}
 
-		_, ipNet, err := net.ParseCIDR(rawCIDR)
+		cidr, err := netip.ParsePrefix(rawCIDR)
 		if err != nil {
 			return nil, fmt.Errorf("config `%s` has invalid CIDR: %s", k, rawCIDR)
 		}
 
+		//TODO: IPV6-WORK this does not verify that rawValue contains the same bits as cidr here
 		entry, err := newCalculatedRemotesListFromConfig(rawValue)
 		if err != nil {
 			return nil, fmt.Errorf("config '%s.%s': %w", k, rawCIDR, err)
 		}
 
-		calculatedRemotes.AddCIDR(ipNet, entry)
+		calculatedRemotes.Insert(cidr, entry)
 	}
 
 	return calculatedRemotes, nil
@@ -117,7 +133,7 @@ func newCalculatedRemotesEntryFromConfig(raw any) (*calculatedRemote, error) {
 	if !ok {
 		return nil, fmt.Errorf("invalid mask (type %T): %v", rawValue, rawValue)
 	}
-	_, ipNet, err := net.ParseCIDR(rawMask)
+	maskCidr, err := netip.ParsePrefix(rawMask)
 	if err != nil {
 		return nil, fmt.Errorf("invalid mask: %s", rawMask)
 	}
@@ -139,5 +155,5 @@ func newCalculatedRemotesEntryFromConfig(raw any) (*calculatedRemote, error) {
 		return nil, fmt.Errorf("invalid port (type %T): %v", rawValue, rawValue)
 	}
 
-	return newCalculatedRemote(ipNet, port)
+	return newCalculatedRemote(maskCidr, port)
 }