Bug 1678614 - Don't try to resolve the host name again when trr mode is trr only r=necko-reviewers,dragana

Differential Revision: https://phabricator.services.mozilla.com/D98024

netwerk/base/nsSocketTransport2.cpp

@@ -1944,13 +1944,19 @@ bool nsSocketTransport::RecoverFromError() {
               mNetAddr.inet6.ip.u64[1] == 0))) {
           SOCKET_LOG(("  TRR returned 0.0.0.0 and there are no other IPs"));
         } else if (trrEnabled) {
-          // Drop state to closed.  This will trigger a new round of
-          // DNS resolving. Bypass the cache this time since the
-          // cached data came from TRR and failed already!
-          SOCKET_LOG(("  failed to connect with TRR enabled, try w/o\n"));
-          mState = STATE_CLOSED;
-          mConnectionFlags |= DISABLE_TRR | BYPASS_CACHE | REFRESH_CACHE;
-          tryAgain = true;
+          nsCOMPtr<nsIDNSService> dns = do_GetService(kDNSServiceCID);
+          uint32_t trrMode = 0;
+          // If current trr mode is trr only, we should not retry.
+          if (dns && NS_SUCCEEDED(dns->GetCurrentTrrMode(&trrMode)) &&
+              trrMode != 3) {
+            // Drop state to closed.  This will trigger a new round of
+            // DNS resolving. Bypass the cache this time since the
+            // cached data came from TRR and failed already!
+            SOCKET_LOG(("  failed to connect with TRR enabled, try w/o\n"));
+            mState = STATE_CLOSED;
+            mConnectionFlags |= DISABLE_TRR | BYPASS_CACHE | REFRESH_CACHE;
+            tryAgain = true;
+          }
         }
       }
     }