New function IsNetworkErrorFatal to invalidate connections on fatal network errors. Use connection.Expires field to trigger removal of inactive connections after a while.

Network Detection.go

@@ -6,7 +6,10 @@ Author:     Peter Kleissner
 
 package core
 
-import "net"
+import (
+	"net"
+	"strings"
+)
 
 // FindInterfaceByIP finds an interface based on the IP. The IP must be available at the interface.
 func FindInterfaceByIP(ip net.IP) (iface *net.Interface, ipnet *net.IPNet) {
@@ -69,3 +72,18 @@ func IsIPv4(IP net.IP) bool {
 func IsIPv6(IP net.IP) bool {
 	return IP.To4() == nil && IP.To16() != nil
 }
+
+// IsNetworkErrorFatal checks if a network error indicates a broken connection.
+// Not every network error indicates a broken connection. This function prevents from over-dropping connections.
+func IsNetworkErrorFatal(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// Windows: A common error when the network adapter is disabled is "wsasendto: The requested address is not valid in its context".
+	if strings.Contains(err.Error(), "requested address is not valid in its context") {
+		return true
+	}
+
+	return false
+}