From e85d792218765c0fe62e7affa81adf4a697da057 Mon Sep 17 00:00:00 2001
From: Mygod <contact-github@mygod.be>
Date: Thu, 4 Oct 2018 16:34:40 +0800
Subject: [PATCH] Refine IpNeighbour parsing

---
 .../be/mygod/vpnhotspot/net/IpNeighbour.kt    | 25 +++++++++----------
 .../net/monitor/IpNeighbourMonitor.kt         |  6 ++---
 .../java/be/mygod/vpnhotspot/util/Utils.kt    |  6 -----
 3 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/net/IpNeighbour.kt b/mobile/src/main/java/be/mygod/vpnhotspot/net/IpNeighbour.kt
index 57877e3d..15a48bb6 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/IpNeighbour.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/IpNeighbour.kt
@@ -1,6 +1,6 @@
 package be.mygod.vpnhotspot.net
 
-import be.mygod.vpnhotspot.util.parseNumericAddressNoThrow
+import be.mygod.vpnhotspot.util.parseNumericAddress
 import timber.log.Timber
 import java.io.File
 import java.io.IOException
@@ -18,23 +18,19 @@ data class IpNeighbour(val ip: InetAddress, val dev: String, val lladdr: String,
          *   https://people.cs.clemson.edu/~westall/853/notes/arpstate.pdf
          * Assumptions: IP addr (key) always present, RTM_GETNEIGH is never used and show_stats = 0
          */
-        private val parser = ("^(Deleted )?(.+?) (dev (.+?) )?(lladdr (.+?))?( router)?( proxy)?" +
+        private val parser = ("^(Deleted )?([^ ]+?) (dev ([^ ]+?) )?(lladdr (.[^ ]+?))?( router)?( proxy)?" +
                 "( ([INCOMPLET,RAHBSDYF]+))?\$").toRegex()
         private fun checkLladdrNotLoopback(lladdr: String) = if (lladdr == "00:00:00:00:00:00") "" else lladdr
 
         fun parse(line: String): IpNeighbour? {
-            val match = parser.matchEntire(line)
-            if (match == null) {
-                if (line.isNotEmpty()) Timber.w(line)
-                return null
-            }
-            val ip = parseNumericAddressNoThrow(match.groupValues[2]) ?: return null
+            val match = parser.matchEntire(line)!!
+            val ip = parseNumericAddress(match.groupValues[2])
             val dev = match.groupValues[4]
             var lladdr = checkLladdrNotLoopback(match.groupValues[6])
             // use ARP as fallback
             if (dev.isNotEmpty() && lladdr.isEmpty()) lladdr = checkLladdrNotLoopback(arp()
                     .asSequence()
-                    .filter { parseNumericAddressNoThrow(it[ARP_IP_ADDRESS]) == ip && it[ARP_DEVICE] == dev }
+                    .filter { parseNumericAddress(it[ARP_IP_ADDRESS]) == ip && it[ARP_DEVICE] == dev }
                     .map { it[ARP_HW_ADDRESS] }
                     .singleOrNull() ?: "")
             val state = if (match.groupValues[1].isNotEmpty() || lladdr.isEmpty()) State.DELETING else
@@ -43,13 +39,16 @@ data class IpNeighbour(val ip: InetAddress, val dev: String, val lladdr: String,
                     "REACHABLE", "DELAY", "STALE", "PROBE", "PERMANENT" -> State.VALID
                     "FAILED" -> State.FAILED
                     "NOARP" -> return null  // skip
-                    else -> {
-                        Timber.w("Unknown state encountered: ${match.groupValues[10]}")
-                        return null
-                    }
+                    else -> throw IllegalArgumentException("Unknown state encountered: ${match.groupValues[10]}")
                 }
             return IpNeighbour(ip, dev, lladdr, state)
         }
+        fun parseNoThrow(line: String): IpNeighbour? = try {
+            parse(line)
+        } catch (e: Exception) {
+            Timber.w(IllegalArgumentException("Unable to parse line: $line", e))
+            null
+        }
 
         private val spaces = " +".toPattern()
         private val mac = "^([0-9a-f]{2}:){5}[0-9a-f]{2}$".toPattern()
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/IpNeighbourMonitor.kt b/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/IpNeighbourMonitor.kt
index 427668fb..f284b640 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/IpNeighbourMonitor.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/IpNeighbourMonitor.kt
@@ -1,7 +1,6 @@
 package be.mygod.vpnhotspot.net.monitor
 
 import be.mygod.vpnhotspot.App.Companion.app
-import be.mygod.vpnhotspot.debugLog
 import be.mygod.vpnhotspot.net.IpNeighbour
 import java.net.InetAddress
 
@@ -39,8 +38,7 @@ class IpNeighbourMonitor private constructor() : IpMonitor() {
 
     override fun processLine(line: String) {
         synchronized(neighbours) {
-            val neighbour = IpNeighbour.parse(line) ?: return
-            debugLog(javaClass.simpleName, line)
+            val neighbour = IpNeighbour.parseNoThrow(line) ?: return
             val changed = if (neighbour.state == IpNeighbour.State.DELETING)
                 neighbours.remove(neighbour.ip) != null
             else neighbours.put(neighbour.ip, neighbour) != neighbour
@@ -52,7 +50,7 @@ class IpNeighbourMonitor private constructor() : IpMonitor() {
         synchronized(neighbours) {
             neighbours.clear()
             neighbours.putAll(lines
-                    .map(IpNeighbour.Companion::parse)
+                    .map(IpNeighbour.Companion::parseNoThrow)
                     .filterNotNull()
                     .filter { it.state != IpNeighbour.State.DELETING }  // skip entries without lladdr
                     .associateBy { it.ip })
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/util/Utils.kt b/mobile/src/main/java/be/mygod/vpnhotspot/util/Utils.kt
index d6634603..391f3faf 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/util/Utils.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/util/Utils.kt
@@ -57,17 +57,11 @@ fun NetworkInterface.formatAddresses() =
                 .joinToString("\n")
 
 private val parseNumericAddress by lazy {
-    // parseNumericAddressNoThrow is in dark grey list unfortunately
     InetAddress::class.java.getDeclaredMethod("parseNumericAddress", String::class.java).apply {
         isAccessible = true
     }
 }
 fun parseNumericAddress(address: String) = parseNumericAddress.invoke(null, address) as InetAddress
-fun parseNumericAddressNoThrow(address: String): InetAddress? = try {
-    parseNumericAddress(address)
-} catch (_: IllegalArgumentException) {
-    null
-}
 
 /**
  * Wrapper for kotlin.concurrent.thread that silences uncaught exceptions.