Ensure hosts results are used

Fixes #2412.
shadowsocks · Jan 19, 2020 · ef1bd7d · ef1bd7d
1 parent e9dc275
commit ef1bd7d
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Showing 3 changed files with 24 additions and 22 deletions.
diff --git a/core/src/main/java/com/github/shadowsocks/bg/ProxyInstance.kt b/core/src/main/java/com/github/shadowsocks/bg/ProxyInstance.kt
@@ -38,9 +38,7 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import java.io.File
 import java.io.IOException
-import java.net.HttpURLConnection
-import java.net.URL
-import java.net.UnknownHostException
+import java.net.*
 import java.security.MessageDigest
 
 /**
@@ -87,16 +85,24 @@ class ProxyInstance(val profile: Profile, private val route: String = profile.ro
 
         // it's hard to resolve DNS on a specific interface so we'll do it here
         if (profile.host.parseNumericAddress() == null) {
-            // if fails/null, use IPv4 only, otherwise pick a random IPv4/IPv6 address
-            val network = service.getActiveNetwork() ?: throw UnknownHostException()
-            val hasIpv4 = DnsResolverCompat.haveIpv4(network)
-            val hasIpv6 = DnsResolverCompat.haveIpv6(network)
-            if (!hasIpv4 && !hasIpv6) throw UnknownHostException()
-            profile.host = (hosts.resolve(profile.host, hasIpv6).firstOrNull() ?: try {
-                service.resolver(profile.host).firstOrNull()
-            } catch (_: IOException) {
-                null
-            })?.hostAddress ?: throw UnknownHostException()
+            profile.host = hosts.resolve(profile.host).run {
+                if (isEmpty()) try {
+                    service.resolver(profile.host).firstOrNull()
+                } catch (_: IOException) {
+                    null
+                } else {
+                    val network = service.getActiveNetwork() ?: throw UnknownHostException()
+                    val hasIpv4 = DnsResolverCompat.haveIpv4(network)
+                    val hasIpv6 = DnsResolverCompat.haveIpv6(network)
+                    firstOrNull {
+                        when (it) {
+                            is Inet4Address -> hasIpv4
+                            is Inet6Address -> hasIpv6
+                            else -> error(it)
+                        }
+                    }
+                }
+            }?.hostAddress ?: throw UnknownHostException()
         }
     }
 

diff --git a/core/src/main/java/com/github/shadowsocks/net/HostsFile.kt b/core/src/main/java/com/github/shadowsocks/net/HostsFile.kt
@@ -21,8 +21,6 @@
 package com.github.shadowsocks.net
 
 import com.github.shadowsocks.utils.parseNumericAddress
-import java.net.Inet4Address
-import java.net.Inet6Address
 import java.net.InetAddress
 
 class HostsFile(input: String = "") {
@@ -36,9 +34,5 @@ class HostsFile(input: String = "") {
     }
 
     val configuredHostnames get() = map.size
-    fun resolve(hostname: String, isIpv6: Boolean): List<InetAddress> {
-        return (map[hostname] ?: return emptyList()).run {
-            if (isIpv6) filterIsInstance<Inet6Address>() else filterIsInstance<Inet4Address>()
-        }.shuffled()
-    }
+    fun resolve(hostname: String) = map[hostname]?.shuffled() ?: emptyList()
 }
diff --git a/core/src/main/java/com/github/shadowsocks/net/LocalDnsServer.kt b/core/src/main/java/com/github/shadowsocks/net/LocalDnsServer.kt
@@ -124,10 +124,12 @@ class LocalDnsServer(private val localResolver: suspend (String) -> Array<InetAd
                     else -> return@supervisorScope remote.await()
                 }
                 val host = question.name.canonicalize().toString(true)
-                val hostsResults = hosts.resolve(host, isIpv6)
+                val hostsResults = hosts.resolve(host)
                 if (hostsResults.isNotEmpty()) {
                     remote.cancel()
-                    return@supervisorScope cookDnsResponse(request, hostsResults)
+                    return@supervisorScope cookDnsResponse(request, hostsResults.run {
+                        if (isIpv6) filterIsInstance<Inet6Address>() else filterIsInstance<Inet4Address>()
+                    })
                 }
                 val acl = acl?.await() ?: return@supervisorScope remote.await()
                 val useLocal = when (acl.shouldBypass(host)) {