From e89707e601c7882e6bc9fe4d1312cc585e545543 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Mon, 4 Nov 2019 21:28:53 -0800
Subject: [PATCH] Don't send a STUN request when a VPN is connected

---
 Limelight/Network/MDNSManager.m | 44 +++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/Limelight/Network/MDNSManager.m b/Limelight/Network/MDNSManager.m
index 0d072d5..67facc9 100644
--- a/Limelight/Network/MDNSManager.m
+++ b/Limelight/Network/MDNSManager.m
@@ -163,6 +163,20 @@ static NSString* NV_SERVICE_TYPE = @"_nvstream._tcp";
     return nil;
 }
 
+- (BOOL)isActiveNetworkVPN {
+    NSDictionary *dict = CFBridgingRelease(CFNetworkCopySystemProxySettings());
+    NSArray *keys = [dict[@"__SCOPED__"] allKeys];
+    for (NSString *key in keys) {
+        if ([key containsString:@"tap"] ||
+            [key containsString:@"tun"] ||
+            [key containsString:@"ppp"] ||
+            [key containsString:@"ipsec"]) {
+            return YES;
+        }
+    }
+    return NO;
+}
+
 - (void)netServiceDidResolveAddress:(NSNetService *)service {
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
         NSArray<NSData*>* addresses = [service addresses];
@@ -180,19 +194,23 @@ static NSString* NV_SERVICE_TYPE = @"_nvstream._tcp";
                 continue;
             }
             
-            // Since we discovered this host over IPv4 mDNS, we know we're on the same network
-            // as the PC and we can use our current WAN address as a likely candidate
-            // for our PC's external address.
-            struct in_addr wanAddr;
-            int err = LiFindExternalAddressIP4("stun.moonlight-stream.org", 3478, &wanAddr.s_addr);
-            if (err == 0) {
-                char addrStr[INET_ADDRSTRLEN];
-                inet_ntop(AF_INET, &wanAddr, addrStr, sizeof(addrStr));
-                host.externalAddress = [NSString stringWithFormat: @"%s", addrStr];
-                Log(LOG_I, @"External IPv4 address (STUN): %@ -> %@", [service hostName], host.externalAddress);
-            }
-            else {
-                Log(LOG_E, @"STUN failed to get WAN address: %d", err);
+            // Don't send a STUN request if we're connected to a VPN. We'll likely get the VPN
+            // gateway's external address rather than the external address of the LAN.
+            if (![self isActiveNetworkVPN]) {
+                // Since we discovered this host over IPv4 mDNS, we know we're on the same network
+                // as the PC and we can use our current WAN address as a likely candidate
+                // for our PC's external address.
+                struct in_addr wanAddr;
+                int err = LiFindExternalAddressIP4("stun.moonlight-stream.org", 3478, &wanAddr.s_addr);
+                if (err == 0) {
+                    char addrStr[INET_ADDRSTRLEN];
+                    inet_ntop(AF_INET, &wanAddr, addrStr, sizeof(addrStr));
+                    host.externalAddress = [NSString stringWithFormat: @"%s", addrStr];
+                    Log(LOG_I, @"External IPv4 address (STUN): %@ -> %@", [service hostName], host.externalAddress);
+                }
+                else {
+                    Log(LOG_E, @"STUN failed to get WAN address: %d", err);
+                }
             }
             
             host.localAddress = [MDNSManager sockAddrToString:addrData];