NE: Simplify DNS resolution

Signed-off-by: Roopesh Chander <roop@roopc.net>

2 files changed, 6 insertions, 23 deletions

diff --git a/WireGuard/WireGuardNetworkExtension/DNSResolver.swift b/WireGuard/WireGuardNetworkExtension/DNSResolver.swift
index 32cbf78..3929862 100644
--- a/WireGuard/WireGuardNetworkExtension/DNSResolver.swift
+++ b/WireGuard/WireGuardNetworkExtension/DNSResolver.swift
@@ -4,10 +4,6 @@
 import Network
 import Foundation
 
-enum DNSResolverError: Error {
-    case dnsResolutionFailed(hostnames: [String])
-}
-
 class DNSResolver {
 
     static func isAllEndpointsAlreadyResolved(endpoints: [Endpoint?]) -> Bool {
@@ -20,7 +16,7 @@ class DNSResolver {
         return true
     }
 
-    static func resolveSync(endpoints: [Endpoint?]) throws -> [Endpoint?] {
+    static func resolveSync(endpoints: [Endpoint?]) -> [Endpoint?]? {
         let dispatchGroup = DispatchGroup()
 
         if isAllEndpointsAlreadyResolved(endpoints: endpoints) {
@@ -56,7 +52,8 @@ class DNSResolver {
             }
         }
         if !hostnamesWithDnsResolutionFailure.isEmpty {
-            throw DNSResolverError.dnsResolutionFailed(hostnames: hostnamesWithDnsResolutionFailure)
+            wg_log(.error, message: "DNS resolution failed for the following hostnames: \(hostnamesWithDnsResolutionFailure.joined(separator: ", "))")
+            return nil
         }
         return resolvedEndpoints
     }
diff --git a/WireGuard/WireGuardNetworkExtension/PacketTunnelProvider.swift b/WireGuard/WireGuardNetworkExtension/PacketTunnelProvider.swift
index 8d71f0b..c418ebc 100644
--- a/WireGuard/WireGuardNetworkExtension/PacketTunnelProvider.swift
+++ b/WireGuard/WireGuardNetworkExtension/PacketTunnelProvider.swift
@@ -58,11 +58,9 @@ class PacketTunnelProvider: NEPacketTunnelProvider {
         errorNotifier.tunnelName = tunnelName
 
         let endpoints = tunnelConfiguration.peers.map { $0.endpoint }
-        guard let resolvedEndpoints = resolveDomainNames(endpoints: endpoints) else {
-            wg_log(.error, staticMessage: "Starting tunnel failed: DNS resolution failure")
-            let dnsError = PacketTunnelProviderError.dnsResolutionFailure
-            errorNotifier.notify(dnsError)
-            startTunnelCompletionHandler(dnsError)
+        guard let resolvedEndpoints = DNSResolver.resolveSync(endpoints: endpoints) else {
+            errorNotifier.notify(PacketTunnelProviderError.dnsResolutionFailure)
+            startTunnelCompletionHandler(PacketTunnelProviderError.dnsResolutionFailure)
             return
         }
         assert(endpoints.count == resolvedEndpoints.count)
@@ -167,18 +165,6 @@ class PacketTunnelProvider: NEPacketTunnelProvider {
         }
     }
 
-    private func resolveDomainNames(endpoints: [Endpoint?]) -> [Endpoint?]? {
-        do {
-            return try DNSResolver.resolveSync(endpoints: endpoints)
-        } catch DNSResolverError.dnsResolutionFailed(let hostnames) {
-            wg_log(.error, message: "DNS resolution failed for the following hostnames: \(hostnames.joined(separator: ", "))")
-        } catch {
-            // There can be no other errors from DNSResolver.resolveSync()
-            fatalError()
-        }
-        return nil
-    }
-
     private func connect(interfaceName: String, settings: String, fileDescriptor: Int32) -> Int32 {
         return withStringsAsGoStrings(interfaceName, settings) { return wgTurnOn($0.0, $0.1, fileDescriptor) }
     }