Merge e177fdb1cd into 951173ba19

This commit fixes jetkvm/kvm#12 by disabling the udhcpc client when the
link goes down, it then removes all the active IPv4 addresses from the
deivce.

Once the link comes back up, it re-activates the udhcpc client so it can
fetch a new IPv4 address for the device.

This doesn't make any changes to the IPv6 side of things yet.

config.go

@@ -22,7 +22,8 @@ type Config struct {
 	LocalAuthToken       string            `json:"local_auth_token"`
 	LocalAuthMode        string            `json:"localAuthMode"` //TODO: fix it with migration
 	WakeOnLanDevices     []WakeOnLanDevice `json:"wake_on_lan_devices"`
-	DisplayMaxBrightness int               `json:"display_max_brightness"`
+	EdidString        string            `json:"hdmi_edid_string"`
+  DisplayMaxBrightness int               `json:"display_max_brightness"`
 	DisplayDimAfterSec   int               `json:"display_dim_after_sec"`
 	DisplayOffAfterSec   int               `json:"display_off_after_sec"`
 }

jsonrpc.go

@@ -189,6 +189,12 @@ func rpcSetEDID(edid string) error {
 	if err != nil {
 		return err
 	}
+
+	// Save EDID to config, allowing it to be restored on reboot.
+	LoadConfig()
+	config.EdidString = edid
+	SaveConfig()
+
 	return nil
 }
 

native.go

@@ -152,6 +152,9 @@ func handleCtrlClient(conn net.Conn) {
 
 	ctrlSocketConn = conn
 
+	// Restore HDMI EDID if applicable
+	go restoreHdmiEdid()
+
 	readBuf := make([]byte, 4096)
 	for {
 		n, err := conn.Read(readBuf)
@@ -304,3 +307,16 @@ func ensureBinaryUpdated(destPath string) error {
 
 	return nil
 }
+
+// Restore the HDMI EDID value from the config.
+// Called after successful connection to jetkvm_native.
+func restoreHdmiEdid() {
+	LoadConfig()
+	if config.EdidString != "" {
+		logger.Infof("Restoring HDMI EDID to %v", config.EdidString)
+		_, err := CallCtrlAction("set_edid", map[string]interface{}{"edid": config.EdidString})
+		if err != nil {
+			logger.Errorf("Failed to restore HDMI EDID: %v", err)
+		}
+	}
+}

network.go

@@ -6,12 +6,15 @@ import (
 	"golang.org/x/net/ipv4"
 	"golang.org/x/net/ipv6"
 	"net"
+	"os/exec"
 	"time"
 
 	"github.com/vishvananda/netlink"
 	"github.com/vishvananda/netlink/nl"
 )
 
+var mDNSConn *mdns.Conn
+
 var networkState struct {
 	Up   bool
 	IPv4 string
@@ -25,6 +28,23 @@ type LocalIpInfo struct {
 	MAC  string
 }
 
+// setDhcpClientState sends signals to udhcpc to change it's current mode
+// of operation. Setting active to true will force udhcpc to renew the DHCP lease.
+// Setting active to false will put udhcpc into idle mode.
+func setDhcpClientState(active bool) {
+	var signal string;
+	if active {
+		signal = "-SIGUSR1"
+	} else {
+		signal = "-SIGUSR2"
+	}
+
+	cmd := exec.Command("/usr/bin/killall", signal, "udhcpc");
+	if err := cmd.Run(); err != nil {
+		fmt.Printf("network: setDhcpClientState: failed to change udhcpc state: %s\n", err)
+	}
+}
+
 func checkNetworkState() {
 	iface, err := netlink.LinkByName("eth0")
 	if err != nil {
@@ -47,22 +67,52 @@ func checkNetworkState() {
 		fmt.Printf("failed to get addresses for eth0: %v\n", err)
 	}
 
+	// If the link is going down, put udhcpc into idle mode.
+	// If the link is coming back up, activate udhcpc and force it to renew the lease.
+	if newState.Up != networkState.Up {
+		setDhcpClientState(newState.Up)
+	}
+
 	for _, addr := range addrs {
 		if addr.IP.To4() != nil {
-			newState.IPv4 = addr.IP.String()
+			if !newState.Up && networkState.Up {
+				// If the network is going down, remove all IPv4 addresses from the interface.
+				fmt.Printf("network: state transitioned to down, removing IPv4 address %s\n", addr.IP.String())
+				err := netlink.AddrDel(iface, &addr)
+				if err != nil {
+					fmt.Printf("network: failed to delete %s", addr.IP.String())
+				}
+
+				newState.IPv4 = "..."
+			} else {
+				newState.IPv4 = addr.IP.String()
+			}
 		} else if addr.IP.To16() != nil && newState.IPv6 == "" {
 			newState.IPv6 = addr.IP.String()
 		}
 	}
 
 	if newState != networkState {
-		networkState = newState
 		fmt.Println("network state changed")
+		//restart MDNS
+		startMDNS()
+		networkState = newState
 		requestDisplayUpdate()
 	}
 }
 
 func startMDNS() error {
+	//If server was previously running, stop it
+	if mDNSConn != nil {
+		fmt.Printf("Stopping mDNS server\n")
+		err := mDNSConn.Close()
+		if err != nil {
+			fmt.Printf("failed to stop mDNS server: %v\n", err)
+		}
+	}
+
+	//Start a new server
+	fmt.Printf("Starting mDNS server on jetkvm.local\n")
 	addr4, err := net.ResolveUDPAddr("udp4", mdns.DefaultAddressIPv4)
 	if err != nil {
 		return err
@@ -83,10 +133,11 @@ func startMDNS() error {
 		return err
 	}
 
-	_, err = mdns.Server(ipv4.NewPacketConn(l4), ipv6.NewPacketConn(l6), &mdns.Config{
+	mDNSConn, err = mdns.Server(ipv4.NewPacketConn(l4), ipv6.NewPacketConn(l6), &mdns.Config{
 		LocalNames: []string{"jetkvm.local"}, //TODO: make it configurable
 	})
 	if err != nil {
+		mDNSConn = nil
 		return err
 	}
 	//defer server.Close()
@@ -122,7 +173,6 @@ func init() {
 			}
 		}
 	}()
-	fmt.Println("Starting mDNS server")
 	err := startMDNS()
 	if err != nil {
 		fmt.Println("failed to run mDNS: %v", err)