Rework some things into packages (#489)

cidr/tree6.go

@@ -0,0 +1,185 @@
+package cidr
+
+import (
+	"net"
+
+	"github.com/slackhq/nebula/iputil"
+)
+
+const startbit6 = uint64(1 << 63)
+
+type Tree6 struct {
+	root4 *Node
+	root6 *Node
+}
+
+func NewTree6() *Tree6 {
+	tree := new(Tree6)
+	tree.root4 = &Node{}
+	tree.root6 = &Node{}
+	return tree
+}
+
+func (tree *Tree6) AddCIDR(cidr *net.IPNet, val interface{}) {
+	var node, next *Node
+
+	cidrIP, ipv4 := isIPV4(cidr.IP)
+	if ipv4 {
+		node = tree.root4
+		next = tree.root4
+
+	} else {
+		node = tree.root6
+		next = tree.root6
+	}
+
+	for i := 0; i < len(cidrIP); i += 4 {
+		ip := iputil.Ip2VpnIp(cidrIP[i : i+4])
+		mask := iputil.Ip2VpnIp(cidr.Mask[i : i+4])
+		bit := startbit
+
+		// Find our last ancestor in the tree
+		for bit&mask != 0 {
+			if ip&bit != 0 {
+				next = node.right
+			} else {
+				next = node.left
+			}
+
+			if next == nil {
+				break
+			}
+
+			bit = bit >> 1
+			node = next
+		}
+
+		// Build up the rest of the tree we don't already have
+		for bit&mask != 0 {
+			next = &Node{}
+			next.parent = node
+
+			if ip&bit != 0 {
+				node.right = next
+			} else {
+				node.left = next
+			}
+
+			bit >>= 1
+			node = next
+		}
+	}
+
+	// Final node marks our cidr, set the value
+	node.value = val
+}
+
+// Finds the most specific match
+func (tree *Tree6) MostSpecificContains(ip net.IP) (value interface{}) {
+	var node *Node
+
+	wholeIP, ipv4 := isIPV4(ip)
+	if ipv4 {
+		node = tree.root4
+	} else {
+		node = tree.root6
+	}
+
+	for i := 0; i < len(wholeIP); i += 4 {
+		ip := iputil.Ip2VpnIp(wholeIP[i : i+4])
+		bit := startbit
+
+		for node != nil {
+			if node.value != nil {
+				value = node.value
+			}
+
+			if bit == 0 {
+				break
+			}
+
+			if ip&bit != 0 {
+				node = node.right
+			} else {
+				node = node.left
+			}
+
+			bit >>= 1
+		}
+	}
+
+	return value
+}
+
+func (tree *Tree6) MostSpecificContainsIpV4(ip iputil.VpnIp) (value interface{}) {
+	bit := startbit
+	node := tree.root4
+
+	for node != nil {
+		if node.value != nil {
+			value = node.value
+		}
+
+		if ip&bit != 0 {
+			node = node.right
+		} else {
+			node = node.left
+		}
+
+		bit >>= 1
+	}
+
+	return value
+}
+
+func (tree *Tree6) MostSpecificContainsIpV6(hi, lo uint64) (value interface{}) {
+	ip := hi
+	node := tree.root6
+
+	for i := 0; i < 2; i++ {
+		bit := startbit6
+
+		for node != nil {
+			if node.value != nil {
+				value = node.value
+			}
+
+			if bit == 0 {
+				break
+			}
+
+			if ip&bit != 0 {
+				node = node.right
+			} else {
+				node = node.left
+			}
+
+			bit >>= 1
+		}
+
+		ip = lo
+	}
+
+	return value
+}
+
+func isIPV4(ip net.IP) (net.IP, bool) {
+	if len(ip) == net.IPv4len {
+		return ip, true
+	}
+
+	if len(ip) == net.IPv6len && isZeros(ip[0:10]) && ip[10] == 0xff && ip[11] == 0xff {
+		return ip[12:16], true
+	}
+
+	return ip, false
+}
+
+func isZeros(p net.IP) bool {
+	for i := 0; i < len(p); i++ {
+		if p[i] != 0 {
+			return false
+		}
+	}
+	return true
+}