dhcpsvc: imp code, docs

internal/dhcpsvc/interface.go

@@ -13,7 +13,8 @@ import (
 type macKey any
 
 // macToKey converts mac into macKey, which is used as the key for the lease
-// maps.
+// maps.  mac must be a valid hardware address of length 6, 8, or 20 bytes, see
+// [netutil.ValidateMAC].
 func macToKey(mac net.HardwareAddr) (key macKey) {
 	switch len(mac) {
 	case 6:

internal/dhcpsvc/server.go

@@ -105,8 +105,8 @@ func newInterfaces(
 	// TODO(e.burkov):  Add validations scoped to the network interfaces set.
 	v4 = make(dhcpInterfacesV4, 0, len(ifaces))
 	v6 = make(dhcpInterfacesV6, 0, len(ifaces))
-	var errs []error
 
+	var errs []error
 	mapsutil.SortedRange(ifaces, func(name string, iface *InterfaceConfig) (cont bool) {
 		var i4 *dhcpInterfaceV4
 		i4, err = newDHCPInterfaceV4(ctx, l, name, iface.IPv4)
@@ -216,7 +216,7 @@ func (srv *DHCPServer) resetLeases() {
 		iface.common.reset()
 	}
 	for _, iface := range srv.interfaces6 {
-		iface.netInterface.reset()
+		iface.common.reset()
 	}
 	srv.leases.clear()
 }

internal/dhcpsvc/v6.go

@@ -64,8 +64,9 @@ func (c *IPv6Config) validate() (err error) {
 
 // dhcpInterfaceV6 is a DHCP interface for IPv6 address family.
 type dhcpInterfaceV6 struct {
-	// netInterface is a network interface handled by DHCP.
-	netInterface *netInterface
+	// common is the common part of any network interface within the DHCP
+	// server.
+	common *netInterface
 
 	// rangeStart is the first IP address in the range.
 	rangeStart netip.Addr
@@ -106,7 +107,7 @@ func newDHCPInterfaceV6(
 
 	i = &dhcpInterfaceV6{
 		rangeStart:   conf.RangeStart,
-		netInterface: newNetInterface(name, l, conf.LeaseDuration),
+		common:       newNetInterface(name, l, conf.LeaseDuration),
 		raSLAACOnly:  conf.RASLAACOnly,
 		raAllowSLAAC: conf.RAAllowSLAAC,
 	}
@@ -137,7 +138,7 @@ func (ifaces dhcpInterfacesV6) find(ip netip.Addr) (iface6 *netInterface, ok boo
 		return nil, false
 	}
 
-	return ifaces[i].netInterface, true
+	return ifaces[i].common, true
 }
 
 // options returns the implicit and explicit options for the interface.  The two