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Allow clients on different tethered interfaces to communicate

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Previously, the routing rules were too strict. We should probably also deprecate TrafficRecord.upstream sometime.
This commit is contained in:
Mygod
2019-01-01 12:18:17 +08:00
parent 8e2b27ff8e
commit 68fface4b9
6 changed files with 87 additions and 138 deletions
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87
mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt
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@@ -4,9 +4,14 @@ import android.os.Build
import be.mygod.vpnhotspot.App.Companion.app
import be.mygod.vpnhotspot.R
import be.mygod.vpnhotspot.net.monitor.FallbackUpstreamMonitor
import be.mygod.vpnhotspot.net.monitor.IpNeighbourMonitor
import be.mygod.vpnhotspot.net.monitor.TrafficRecorder
import be.mygod.vpnhotspot.net.monitor.UpstreamMonitor
import be.mygod.vpnhotspot.room.AppDatabase
import be.mygod.vpnhotspot.room.lookup
import be.mygod.vpnhotspot.room.macToLong
import be.mygod.vpnhotspot.util.RootSession
import be.mygod.vpnhotspot.util.computeIfAbsentCompat
import be.mygod.vpnhotspot.widget.SmartSnackbar
import timber.log.Timber
import java.lang.RuntimeException
@@ -18,7 +23,7 @@ import java.util.concurrent.atomic.AtomicLong
*
* Once revert is called, this object no longer serves any purpose.
*/
class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) : IpNeighbourMonitor.Callback {
companion object {
/**
* Since Android 5.0, RULE_PRIORITY_TETHERING = 18000.
@@ -55,9 +60,9 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
}
}
fun RootSession.Transaction.iptablesAdd(content: String, table: String = "filter") =
private fun RootSession.Transaction.iptablesAdd(content: String, table: String = "filter") =
exec("$IPTABLES -t $table -A $content", "$IPTABLES -t $table -D $content", true)
fun RootSession.Transaction.iptablesInsert(content: String, table: String = "filter") =
private fun RootSession.Transaction.iptablesInsert(content: String, table: String = "filter") =
exec("$IPTABLES -t $table -I $content", "$IPTABLES -t $table -D $content", true)
}
@@ -74,6 +79,24 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
private val upstreams = HashSet<String>()
private open inner class Upstream(val priority: Int) : UpstreamMonitor.Callback {
/**
* The only case when upstream is null is on API 23- and we are using system default rules.
*/
inner class Subrouting(priority: Int, val upstream: String? = null) {
val transaction = RootSession.beginTransaction().safeguard {
if (upstream != null) {
exec("ip rule add from all iif $downstream lookup $upstream priority $priority",
// by the time stopScript is called, table entry for upstream may already get removed
"ip rule del from all iif $downstream priority $priority")
}
// note: specifying -i wouldn't work for POSTROUTING
if (hasMasquerade) {
iptablesAdd(if (upstream == null) "vpnhotspot_masquerade -s $hostSubnet -j MASQUERADE" else
"vpnhotspot_masquerade -s $hostSubnet -o $upstream -j MASQUERADE", "nat")
}
}
}
var subrouting: Subrouting? = null
var dns: List<InetAddress> = emptyList()
@@ -83,7 +106,7 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
subrouting != null -> check(subrouting.upstream == ifname)
!upstreams.add(ifname) -> return
else -> this.subrouting = try {
Subrouting(this@Routing, priority, ifname)
Subrouting(priority, ifname)
} catch (e: Exception) {
SmartSnackbar.make(e).show()
Timber.w(e)
@@ -98,9 +121,7 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
val subrouting = subrouting ?: return
// we could be removing fallback subrouting which no collision could ever happen, check before removing
if (subrouting.upstream != null) check(upstreams.remove(subrouting.upstream))
subrouting.close()
TrafficRecorder.update() // record stats before removing rules to prevent stats losing
subrouting.revert()
subrouting.transaction.revert()
this.subrouting = null
dns = emptyList()
updateDnsRoute()
@@ -110,7 +131,7 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
override fun onFallback() = synchronized(this@Routing) {
check(subrouting == null)
subrouting = try {
Subrouting(this@Routing, priority)
Subrouting(priority)
} catch (e: Exception) {
SmartSnackbar.make(e).show()
Timber.w(e)
@@ -121,6 +142,47 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
}
private val upstream = Upstream(RULE_PRIORITY_UPSTREAM)
private inner class Client(private val ip: Inet4Address, mac: String) : AutoCloseable {
private val transaction = RootSession.beginTransaction().safeguard {
val address = ip.hostAddress
iptablesInsert("vpnhotspot_fwd -i $downstream -s $address -j ACCEPT")
iptablesInsert("vpnhotspot_fwd -o $downstream -d $address -m state --state ESTABLISHED,RELATED -j ACCEPT")
}
init {
try {
TrafficRecorder.register(ip, downstream, mac)
} catch (e: Exception) {
close()
throw e
}
}
override fun close() {
TrafficRecorder.unregister(ip, downstream)
transaction.revert()
}
}
private val clients = HashMap<InetAddress, Client>()
override fun onIpNeighbourAvailable(neighbours: List<IpNeighbour>) = synchronized(this) {
val toRemove = HashSet(clients.keys)
for (neighbour in neighbours) {
if (neighbour.dev != downstream || neighbour.ip !is Inet4Address ||
AppDatabase.instance.clientRecordDao.lookup(neighbour.lladdr.macToLong()).blocked) continue
toRemove.remove(neighbour.ip)
try {
clients.computeIfAbsentCompat(neighbour.ip) { Client(neighbour.ip, neighbour.lladdr) }
} catch (e: Exception) {
Timber.w(e)
SmartSnackbar.make(e).show()
}
}
if (toRemove.isNotEmpty()) {
TrafficRecorder.update() // record stats before removing rules to prevent stats losing
for (address in toRemove) clients.remove(address)!!.close()
}
}
fun ipForward() = transaction.exec("echo 1 >/proc/sys/net/ipv4/ip_forward")
fun disableIpv6() = transaction.exec("echo 1 >/proc/sys/net/ipv6/conf/$downstream/disable_ipv6",
@@ -181,22 +243,23 @@ class Routing(val downstream: String, ownerAddress: InterfaceAddress? = null) {
}
fun stop() {
IpNeighbourMonitor.unregisterCallback(this)
FallbackUpstreamMonitor.unregisterCallback(fallbackUpstream)
fallbackUpstream.subrouting?.close()
UpstreamMonitor.unregisterCallback(upstream)
upstream.subrouting?.close()
}
fun commit() {
transaction.commit()
FallbackUpstreamMonitor.registerCallback(fallbackUpstream)
UpstreamMonitor.registerCallback(upstream)
IpNeighbourMonitor.registerCallback(this)
}
fun revert() {
stop()
TrafficRecorder.update() // record stats before exiting to prevent stats losing
fallbackUpstream.subrouting?.revert()
upstream.subrouting?.revert()
clients.forEach { (_, subroute) -> subroute.close() }
fallbackUpstream.subrouting?.transaction?.revert()
upstream.subrouting?.transaction?.revert()
transaction.revert()
}
}