Group net package

2018-01-20 18:37:45 -08:00
parent 610c6403ea
commit 2108c635ce
8 changed files with 23 additions and 11 deletions
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt
@@ -0,0 +1,89 @@
+package be.mygod.vpnhotspot.net
+
+import android.os.Build
+import be.mygod.vpnhotspot.App.Companion.app
+import be.mygod.vpnhotspot.R
+import be.mygod.vpnhotspot.noisySu
+import java.io.IOException
+import java.net.Inet4Address
+import java.net.InetAddress
+import java.net.NetworkInterface
+import java.util.*
+
+class Routing(private val upstream: String, val downstream: String, ownerAddress: InetAddress? = null) {
+    companion object {
+        /**
+         * -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-.
+         *
+         * Source: https://android.googlesource.com/platform/external/iptables/+/android-5.0.0_r1/iptables/iptables.c#1574
+         */
+        private val IPTABLES = if (Build.VERSION.SDK_INT >= 26) "iptables -w 1" else "iptables -w"
+
+        fun clean() = noisySu(
+                "$IPTABLES -t nat -F PREROUTING",
+                "quiet while $IPTABLES -D FORWARD -j vpnhotspot_fwd; do done",
+                "$IPTABLES -F vpnhotspot_fwd",
+                "$IPTABLES -X vpnhotspot_fwd",
+                "quiet while ip rule del priority 17900; do done")
+    }
+
+    class InterfaceNotFoundException : IOException() {
+        override val message: String get() = app.getString(R.string.exception_interface_not_found)
+    }
+
+    val hostAddress = ownerAddress ?: NetworkInterface.getByName(downstream)?.inetAddresses?.asSequence()
+            ?.singleOrNull { it is Inet4Address } ?: throw InterfaceNotFoundException()
+    private val startScript = LinkedList<String>()
+    private val stopScript = LinkedList<String>()
+    var started = false
+
+    fun ipForward(): Routing {
+        startScript.add("echo 1 >/proc/sys/net/ipv4/ip_forward")
+        return this
+    }
+
+    /**
+     * Since Android 5.0, RULE_PRIORITY_TETHERING = 18000.
+     * This also works for Wi-Fi direct where there's no rule at 18000.
+     *
+     * Source: https://android.googlesource.com/platform/system/netd/+/b9baf26/server/RouteController.cpp#65
+     */
+    fun rule(): Routing {
+        startScript.add("ip rule add from all iif $downstream lookup $upstream priority 17900")
+        // by the time stopScript is called, table entry for upstream may already get removed
+        stopScript.addFirst("ip rule del from all iif $downstream priority 17900")
+        return this
+    }
+
+    fun forward(): Routing {
+        startScript.add("quiet $IPTABLES -N vpnhotspot_fwd 2>/dev/null")
+        startScript.add("$IPTABLES -A vpnhotspot_fwd -i $upstream -o $downstream -m state --state ESTABLISHED,RELATED -j ACCEPT")
+        startScript.add("$IPTABLES -A vpnhotspot_fwd -i $downstream -o $upstream -j ACCEPT")
+        startScript.add("$IPTABLES -I FORWARD -j vpnhotspot_fwd")
+        stopScript.addFirst("$IPTABLES -D vpnhotspot_fwd -i $upstream -o $downstream -m state --state ESTABLISHED,RELATED -j ACCEPT")
+        stopScript.addFirst("$IPTABLES -D vpnhotspot_fwd -i $downstream -o $upstream -j ACCEPT")
+        stopScript.addFirst("$IPTABLES -D FORWARD -j vpnhotspot_fwd")
+        return this
+    }
+
+    fun dnsRedirect(dns: String): Routing {
+        val hostAddress = hostAddress.hostAddress
+        startScript.add("$IPTABLES -t nat -A PREROUTING -i $downstream -p tcp -d $hostAddress --dport 53 -j DNAT --to-destination $dns")
+        startScript.add("$IPTABLES -t nat -A PREROUTING -i $downstream -p udp -d $hostAddress --dport 53 -j DNAT --to-destination $dns")
+        stopScript.addFirst("$IPTABLES -t nat -D PREROUTING -i $downstream -p tcp -d $hostAddress --dport 53 -j DNAT --to-destination $dns")
+        stopScript.addFirst("$IPTABLES -t nat -D PREROUTING -i $downstream -p udp -d $hostAddress --dport 53 -j DNAT --to-destination $dns")
+        return this
+    }
+
+    fun start(): Boolean {
+        if (started) return true
+        started = true
+        return noisySu(startScript)
+    }
+    fun stop(): Boolean {
+        if (!started) return true
+        started = false
+        return noisySu(stopScript)
+    }
+}