Refine masquerade rules

mobile/src/main/java/be/mygod/vpnhotspot/LocalOnlyInterfaceManager.kt

@@ -6,10 +6,10 @@ import be.mygod.vpnhotspot.net.Routing
 import be.mygod.vpnhotspot.net.UpstreamMonitor
 import com.crashlytics.android.Crashlytics
 import java.net.InetAddress
+import java.net.InterfaceAddress
 import java.net.SocketException
 
-class LocalOnlyInterfaceManager(val downstream: String, private val owner: InetAddress? = null) :
+class LocalOnlyInterfaceManager(val downstream: String) : UpstreamMonitor.Callback {
-        UpstreamMonitor.Callback {
     private var routing: Routing? = null
     private var dns = emptyList<InetAddress>()
 
@@ -20,7 +20,7 @@ class LocalOnlyInterfaceManager(val downstream: String, private val owner: InetA
 
     override fun onAvailable(ifname: String, dns: List<InetAddress>) {
         val routing = routing
-        initRouting(ifname, if (routing == null) owner else {
+        initRouting(ifname, if (routing == null) null else {
             routing.stop()
             routing.hostAddress
         }, dns)
@@ -37,7 +37,7 @@ class LocalOnlyInterfaceManager(val downstream: String, private val owner: InetA
         initRouting(routing.upstream, routing.hostAddress, dns)
     }
 
-    private fun initRouting(upstream: String? = null, owner: InetAddress? = this.owner,
+    private fun initRouting(upstream: String? = null, owner: InterfaceAddress? = null,
                             dns: List<InetAddress> = this.dns) {
         try {
             val routing = Routing(upstream, downstream, owner)

mobile/src/main/java/be/mygod/vpnhotspot/RepeaterService.kt

@@ -226,15 +226,15 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
         } else if (routingManager != null) {
             this.group = group
             showNotification(group)
-        } else doStart(group, info.groupOwnerAddress)
+        } else doStart(group)
     }
     /**
      * startService Step 3
      */
-    private fun doStart(group: WifiP2pGroup, ownerAddress: InetAddress? = null) {
+    private fun doStart(group: WifiP2pGroup) {
         this.group = group
         check(routingManager == null)
-        routingManager = LocalOnlyInterfaceManager(group.`interface`!!, ownerAddress)
+        routingManager = LocalOnlyInterfaceManager(group.`interface`!!)
         status = Status.ACTIVE
         showNotification(group)
     }

mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt

@@ -5,13 +5,10 @@ import be.mygod.vpnhotspot.App.Companion.app
 import be.mygod.vpnhotspot.R
 import be.mygod.vpnhotspot.util.debugLog
 import be.mygod.vpnhotspot.util.noisySu
-import java.net.Inet4Address
+import java.net.*
-import java.net.InetAddress
-import java.net.NetworkInterface
-import java.net.SocketException
 import java.util.*
 
-class Routing(val upstream: String?, private val downstream: String, ownerAddress: InetAddress? = null) {
+class Routing(val upstream: String?, private val downstream: String, ownerAddress: InterfaceAddress? = null) {
     companion object {
         /**
          * -w <seconds> is not supported on 7.1-.
@@ -37,8 +34,8 @@ class Routing(val upstream: String?, private val downstream: String, ownerAddres
         override val message: String get() = app.getString(R.string.exception_interface_not_found)
     }
 
-    val hostAddress = ownerAddress ?: NetworkInterface.getByName(downstream)?.inetAddresses?.asSequence()
+    val hostAddress = ownerAddress ?: NetworkInterface.getByName(downstream)?.interfaceAddresses?.asSequence()
-            ?.singleOrNull { it is Inet4Address } ?: throw InterfaceNotFoundException()
+            ?.singleOrNull { it.address is Inet4Address } ?: throw InterfaceNotFoundException()
     private val startScript = LinkedList<String>()
     private val stopScript = LinkedList<String>()
     var started = false
@@ -91,15 +88,16 @@ class Routing(val upstream: String?, private val downstream: String, ownerAddres
     }
 
     fun masquerade(strict: Boolean = true): Routing {
+        val hostSubnet = "${hostAddress.address.hostAddress}/${hostAddress.networkPrefixLength}"
         startScript.add("quiet $IPTABLES -t nat -N vpnhotspot_masquerade 2>/dev/null")
         // note: specifying -i wouldn't work for POSTROUTING
         if (strict) {
             check(upstream != null)
-            startScript.add("$IPTABLES -t nat -A vpnhotspot_masquerade -o $upstream -j MASQUERADE")
+            startScript.add("$IPTABLES -t nat -A vpnhotspot_masquerade -s $hostSubnet -o $upstream -j MASQUERADE")
-            stopScript.addFirst("$IPTABLES -t nat -D vpnhotspot_masquerade -o $upstream -j MASQUERADE")
+            stopScript.addFirst("$IPTABLES -t nat -D vpnhotspot_masquerade -s $hostSubnet -o $upstream -j MASQUERADE")
         } else {
-            startScript.add("$IPTABLES -t nat -A vpnhotspot_masquerade -j MASQUERADE")
+            startScript.add("$IPTABLES -t nat -A vpnhotspot_masquerade -s $hostSubnet -j MASQUERADE")
-            stopScript.addFirst("$IPTABLES -t nat -D vpnhotspot_masquerade -j MASQUERADE")
+            stopScript.addFirst("$IPTABLES -t nat -D vpnhotspot_masquerade -s $hostSubnet -j MASQUERADE")
         }
         startScript.add("$IPTABLES -t nat -I POSTROUTING -j vpnhotspot_masquerade")
         stopScript.addFirst("$IPTABLES -t nat -D POSTROUTING -j vpnhotspot_masquerade")
@@ -107,7 +105,7 @@ class Routing(val upstream: String?, private val downstream: String, ownerAddres
     }
 
     fun dnsRedirect(dnses: List<InetAddress>): Routing {
-        val hostAddress = hostAddress.hostAddress
+        val hostAddress = hostAddress.address.hostAddress
         val dns = dnses.firstOrNull { it is Inet4Address }?.hostAddress ?: app.dns
         debugLog("Routing", "Using $dns from ($dnses)")
         startScript.add("$IPTABLES -t nat -A PREROUTING -i $downstream -p tcp -d $hostAddress --dport 53 -j DNAT --to-destination $dns")