From b7aaae7513a29e4082fc5e607ea514387a066408 Mon Sep 17 00:00:00 2001
From: Roopesh Chander <roop@roopc.net>
Date: Mon, 29 Oct 2018 06:00:31 +0530
Subject: [PATCH] VPN: If we don't have to make a DNS request, we shouldn't
 enter that status

Signed-off-by: Roopesh Chander <roop@roopc.net>
---
 WireGuard/WireGuard/VPN/DNSResolver.swift    | 14 +++++++
 WireGuard/WireGuard/VPN/TunnelsManager.swift | 42 ++++++++++++++------
 2 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/WireGuard/WireGuard/VPN/DNSResolver.swift b/WireGuard/WireGuard/VPN/DNSResolver.swift
index c047966..c7cf6c5 100644
--- a/WireGuard/WireGuard/VPN/DNSResolver.swift
+++ b/WireGuard/WireGuard/VPN/DNSResolver.swift
@@ -16,6 +16,20 @@ class DNSResolver {
         self.dispatchGroup = DispatchGroup()
     }
 
+    func resolveWithoutNetworkRequests() -> [Endpoint?]? {
+        var resolvedEndpoints: [Endpoint?] = Array<Endpoint?>(repeating: nil, count: endpoints.count)
+        for (i, endpoint) in self.endpoints.enumerated() {
+            guard let endpoint = endpoint else { continue }
+            if let resolvedEndpointStringInCache = DNSResolver.cache.object(forKey: endpoint.stringRepresentation() as NSString),
+                let resolvedEndpointInCache = Endpoint(from: resolvedEndpointStringInCache as String) {
+                resolvedEndpoints[i] = resolvedEndpointInCache
+            } else {
+                return nil
+            }
+        }
+        return resolvedEndpoints
+    }
+
     func resolve(completionHandler: @escaping ([Endpoint?]?) -> Void) {
         let endpoints = self.endpoints
         let dispatchGroup = self.dispatchGroup
diff --git a/WireGuard/WireGuard/VPN/TunnelsManager.swift b/WireGuard/WireGuard/VPN/TunnelsManager.swift
index 76d5c05..1210d7e 100644
--- a/WireGuard/WireGuard/VPN/TunnelsManager.swift
+++ b/WireGuard/WireGuard/VPN/TunnelsManager.swift
@@ -261,19 +261,9 @@ class TunnelContainer: NSObject {
         let endpoints = tunnelConfiguration.peers.map { $0.endpoint }
         let dnsResolver = DNSResolver(endpoints: endpoints)
         assert(self.dnsResolver == nil)
-        self.dnsResolver = dnsResolver
-        status = .resolvingEndpointDomains
-        dnsResolver.resolve { [weak self] endpoints in
-            guard let s = self else { return }
-            assert(s.status == .resolvingEndpointDomains)
-            s.dnsResolver = nil
-            guard let endpoints = endpoints else {
-                completionHandler(TunnelsManagerError.dnsResolutionFailed)
-                s.status = .inactive
-                return
-            }
-            s.tunnelProvider.loadFromPreferences { [weak s] (error) in
-                guard let s = s else { return }
+        if let endpoints = dnsResolver.resolveWithoutNetworkRequests() {
+            self.tunnelProvider.loadFromPreferences { [weak self] (error) in
+                guard let s = self else { return }
                 s.startObservingTunnelStatus()
                 let session = (s.tunnelProvider.connection as! NETunnelProviderSession)
                 do {
@@ -285,6 +275,32 @@ class TunnelContainer: NSObject {
                     completionHandler(error)
                 }
             }
+        } else {
+            self.dnsResolver = dnsResolver
+            status = .resolvingEndpointDomains
+            dnsResolver.resolve { [weak self] endpoints in
+                guard let s = self else { return }
+                assert(s.status == .resolvingEndpointDomains)
+                s.dnsResolver = nil
+                guard let endpoints = endpoints else {
+                    completionHandler(TunnelsManagerError.dnsResolutionFailed)
+                    s.status = .inactive
+                    return
+                }
+                s.tunnelProvider.loadFromPreferences { [weak s] (error) in
+                    guard let s = s else { return }
+                    s.startObservingTunnelStatus()
+                    let session = (s.tunnelProvider.connection as! NETunnelProviderSession)
+                    do {
+                        let tunnelOptions = PacketTunnelOptionsGenerator.generateOptions(
+                            from: tunnelConfiguration, withResolvedEndpoints: endpoints)
+                        try session.startTunnel(options: tunnelOptions)
+                    } catch (let error) {
+                        os_log("Failed to activate tunnel: %{public}@", log: OSLog.default, type: .debug, "\(error)")
+                        completionHandler(error)
+                    }
+                }
+            }
         }
     }