internal/clientinfo: add NDP discovery

internal/clientinfo/ndp_linux.go

@@ -0,0 +1,24 @@
+package clientinfo
+
+import (
+	"github.com/vishvananda/netlink"
+
+	"github.com/Control-D-Inc/ctrld"
+)
+
+// scan populates NDP table using information from system mappings.
+func (nd *ndpDiscover) scan() {
+	neighs, err := netlink.NeighList(0, netlink.FAMILY_V6)
+	if err != nil {
+		ctrld.ProxyLogger.Load().Warn().Err(err).Msg("could not get neigh list")
+		return
+	}
+
+	for _, n := range neighs {
+		ip := n.IP.String()
+		mac := n.HardwareAddr.String()
+		nd.mac.Store(ip, mac)
+		nd.ip.Store(mac, ip)
+	}
+
+}