all: imp code & docs

internal/aghnet/net_freebsd.go

@@ -31,7 +31,6 @@ func ifaceHasStaticIP(ifaceName string) (ok bool, err error) {
 	if err != nil {
 		return false, err
 	}
-
 	defer func() { err = errors.WithDeferred(err, f.Close()) }()
 
 	var r io.Reader
@@ -40,12 +39,12 @@ func ifaceHasStaticIP(ifaceName string) (ok bool, err error) {
 		return false, err
 	}
 
-	return rcconfStaticConfig(r, ifaceName)
+	return rcConfStaticConfig(r, ifaceName)
 }
 
-// rcconfStaticConfig checks if the interface is configured by /etc/rc.conf to
+// rcConfStaticConfig checks if the interface is configured by /etc/rc.conf to
 // have a static IP.
-func rcconfStaticConfig(r io.Reader, ifaceName string) (has bool, err error) {
+func rcConfStaticConfig(r io.Reader, ifaceName string) (has bool, err error) {
 	s := bufio.NewScanner(r)
 	for ifaceLinePref := fmt.Sprintf("ifconfig_%s", ifaceName); s.Scan(); {
 		line := strings.TrimSpace(s.Text())

internal/aghnet/net_freebsd_test.go

@@ -11,7 +11,7 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestRcconfStaticConfig(t *testing.T) {
+func TestRcConfStaticConfig(t *testing.T) {
 	const ifaceName = `em0`
 	const nl = "\n"
 
@@ -51,7 +51,7 @@ func TestRcconfStaticConfig(t *testing.T) {
 	for _, tc := range testCases {
 		r := strings.NewReader(tc.rcconfData)
 		t.Run(tc.name, func(t *testing.T) {
-			has, err := rcconfStaticConfig(r, ifaceName)
+			has, err := rcConfStaticConfig(r, ifaceName)
 			require.NoError(t, err)
 
 			assert.Equal(t, tc.wantHas, has)

internal/dhcpd/server.go

@@ -38,8 +38,8 @@ type V4ServerConf struct {
 
 	GatewayIP  net.IP `yaml:"gateway_ip" json:"gateway_ip"`
 	SubnetMask net.IP `yaml:"subnet_mask" json:"subnet_mask"`
-	// broadcastIP is the broadcasting address specific for the configured
-	// interface.
+	// broadcastIP is the broadcasting address pre-calculated from the
+	// configured gateway IP and subnet mask.
 	broadcastIP net.IP
 
 	// The first & the last IP address for dynamic leases

internal/dhcpd/v4.go

@@ -927,15 +927,23 @@ func (s *v4Server) packetHandler(conn net.PacketConn, peer net.Addr, req *dhcpv4
 		resp.Options.Update(dhcpv4.OptMessageType(dhcpv4.MessageTypeNak))
 	}
 
-	upeer, ok := peer.(*net.UDPAddr)
+	// peer is expected to be of type *net.UDPConn as the server4.NewServer
+	// initializes it.
+	udpPeer, ok := peer.(*net.UDPAddr)
 	if !ok {
 		log.Error("dhcpv4: peer is of unexpected type %T", peer)
 
 		return
 	}
 
-	if upeer.IP.Equal(net.IPv4bcast) {
-		upeer.IP = s.conf.broadcastIP
+	// Despite the fact that server4.NewIPv4UDPConn explicitly sets socket
+	// options to allow broadcasting, it's also binds the connection to the
+	// specified interface.  On FreeBSD conn.WriteTo causes errors while
+	// writing to the addresses that belong to another interface.  So use
+	// the broadcast address specific for the binded interface in case the
+	// server4.Serve method sets it to net.IPv4Bcast.
+	if udpPeer.IP.Equal(net.IPv4bcast) {
+		udpPeer.IP = s.conf.broadcastIP
 	}
 
 	log.Debug("dhcpv4: sending: %s", resp.Summary())