brianhansonxyz/vpnhotspotmod
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Make DHCP workaround global

Browse Source
This commit is contained in:
Mygod
2019-02-01 16:55:38 +08:00
parent 6a7a16a0c7
commit a71a3b3bb0
6 changed files with 45 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
mobile/src/main/java/be/mygod/vpnhotspot/net/DhcpWorkaround.kt Normal file
View File

@@ -0,0 +1,41 @@
package be.mygod.vpnhotspot.net
import android.content.SharedPreferences
import be.mygod.vpnhotspot.App.Companion.app
import be.mygod.vpnhotspot.util.RootSession
import be.mygod.vpnhotspot.widget.SmartSnackbar
import timber.log.Timber
/**
* Assuming RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL = 11000.
* Normally this is used to forward packets from remote to local, but it works anyways.
* It just needs to be before RULE_PRIORITY_SECURE_VPN = 12000.
* It would be great if we can gain better understanding into why this is only needed on some of the devices but not
* others.
*
* Source: https://android.googlesource.com/platform/system/netd/+/b9baf26/server/RouteController.cpp#57
*/
object DhcpWorkaround : SharedPreferences.OnSharedPreferenceChangeListener {
private const val KEY_ENABLED = "service.dhcpWorkaround"
init {
app.pref.registerOnSharedPreferenceChangeListener(this)
}
val shouldEnable get() = app.pref.getBoolean(KEY_ENABLED, false)
fun enable(enabled: Boolean) {
val action = if (enabled) "add" else "del"
try {
RootSession.use { it.exec("ip rule $action iif lo uidrange 0-0 lookup local_network priority 11000") }
} catch (e: RootSession.UnexpectedOutputException) {
if (e.result.code == 2 && e.result.out.isEmpty() &&
e.result.err.joinToString("\n") == "RTNETLINK answers: File exists") return
Timber.w(e)
SmartSnackbar.make(e).show()
}
}
override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences?, key: String?) {
if (key == KEY_ENABLED) enable(shouldEnable)
}
}

20
mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt
View File

@@ -14,7 +14,6 @@ import be.mygod.vpnhotspot.widget.SmartSnackbar
import kotlinx.coroutines.runBlocking
import timber.log.Timber
import java.net.*
import java.util.concurrent.atomic.AtomicLong
/**
* A transaction wrapper that helps set up routing environment.
@@ -32,8 +31,6 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) :
private const val RULE_PRIORITY_UPSTREAM = 17800
private const val RULE_PRIORITY_UPSTREAM_FALLBACK = 17900
private val dhcpWorkaroundCounter = AtomicLong()
/**
* -w <seconds> is not supported on 7.1-.
* Fortunately there also isn't a time limit for starting a foreground service back in 7.1-.
@@ -55,7 +52,6 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) :
it.execQuiet("$IPTABLES -t nat -X vpnhotspot_masquerade")
it.execQuiet("while ip rule del priority $RULE_PRIORITY_UPSTREAM; do done")
it.execQuiet("while ip rule del priority $RULE_PRIORITY_UPSTREAM_FALLBACK; do done")
it.execQuiet("while ip rule del iif lo uidrange 0-0 lookup local_network priority 11000; do done")
}
}
@@ -253,22 +249,6 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) :
}
}
/**
* Similarly, assuming RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL = 11000.
* Normally this is used to forward packets from remote to local, but it works anyways. It just needs to be before
* RULE_PRIORITY_SECURE_VPN = 12000. It would be great if we can gain better understanding into why this is only
* needed on some of the devices but not others.
*
* Source: https://android.googlesource.com/platform/system/netd/+/b9baf26/server/RouteController.cpp#57
*/
fun dhcpWorkaround() {
// workaround for adding multiple exact same rules
// if somebody decides to do this 1000 times to break this, god bless you
val priority = 11000 + dhcpWorkaroundCounter.getAndAdd(1) % 1000
transaction.exec("ip rule add iif lo uidrange 0-0 lookup local_network priority $priority",
"ip rule del iif lo uidrange 0-0 lookup local_network priority $priority")
}
fun stop() {
IpNeighbourMonitor.unregisterCallback(this)
FallbackUpstreamMonitor.unregisterCallback(fallbackUpstream)