From 35e10ea8e6b6759c21df044eae0092b42f7c09c0 Mon Sep 17 00:00:00 2001
From: abraunegg <alex.braunegg@gmail.com>
Date: Fri, 10 Oct 2025 13:55:31 +1100
Subject: [PATCH] Fix Bug #3463: Force DNS Timeout when forcing a libcurl fresh
 connection (#3468)

* Force DNS Timeout when forcing a libcurl fresh connection which will force DNS resolution as stale cache internally in curl is not being released
* Fix that 'online' state is correctly set if Internet access is not available at startup when using --monitor
---
 src/main.d     |  5 ++---
 src/onedrive.d | 17 +++++++++++++++--
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/main.d b/src/main.d
index ad041957..3e1876f2 100644
--- a/src/main.d
+++ b/src/main.d
@@ -575,9 +575,8 @@ int main(string[] cliArgs) {
 			addLogEntry();
 			addLogEntry("Unable to reach the Microsoft OneDrive API service at this point in time, re-trying network tests based on applicable intervals");
 			addLogEntry();
-			if (!retryInternetConnectivityTest(appConfig)) {
-				return EXIT_FAILURE;
-			}
+			// Run the re-try of Internet connectivity test
+			online = retryInternetConnectivityTest(appConfig);
 		}
 	}
 	
diff --git a/src/onedrive.d b/src/onedrive.d
index 65919ce8..08ef7caa 100644
--- a/src/onedrive.d
+++ b/src/onedrive.d
@@ -1752,8 +1752,7 @@ class OneDriveApi {
 							addLogEntry("Internet connectivity to Microsoft OneDrive service has been restored");
 						}
 						// unset the fresh connect option as this then creates performance issues if left enabled
-						if (debugLogging) {addLogEntry("Unsetting libcurl to use a fresh connection as this causes a performance impact if left enabled", ["debug"]);}
-						curlEngine.http.handle.set(CurlOption.fresh_connect,0);
+						unsetFreshConnectOption();
 					}
 					
 					// On successful processing, break out of the loop
@@ -2095,6 +2094,20 @@ class OneDriveApi {
 	private void setFreshConnectOption() {
 		if (debugLogging) {addLogEntry("Configuring libcurl to use a fresh connection for re-try", ["debug"]);}
 		curlEngine.http.handle.set(CurlOption.fresh_connect,1);
+		// Set libcurl dns_cache_timeout timeout
+		// https://curl.se/libcurl/c/CURLOPT_DNS_CACHE_TIMEOUT.html
+		// https://dlang.org/library/std/net/curl/http.dns_timeout.html
+		curlEngine.http.dnsTimeout = (dur!"seconds"(0));
+	}
+	
+	// Unset the libcurl fresh connection options and reset libcurl DNS Cache Timeout
+	private void unsetFreshConnectOption() {
+		if (debugLogging) {addLogEntry("Unsetting libcurl to use a fresh connection as this causes a performance impact if left enabled", ["debug"]);}
+		curlEngine.http.handle.set(CurlOption.fresh_connect,0);
+		// Reset libcurl dns_cache_timeout timeout
+		// https://curl.se/libcurl/c/CURLOPT_DNS_CACHE_TIMEOUT.html
+		// https://dlang.org/library/std/net/curl/http.dns_timeout.html
+		curlEngine.http.dnsTimeout = (dur!"seconds"(appConfig.getValueLong("dns_timeout")));
 	}
 	
 	// Generate a HTTP 'reason' based on the HTTP 'code'