@@ -221,6 +221,11 @@
* interface basis and is computed by
* 'compute_low_priority_metric'.
*
+ * There is one exception to the above. When the Linux kernel
+ * recognizes that the next hop for a route becomes unreachable, it
+ * is automatically purged from the routing table with no
+ * RTM_DELROUTE RTNL notification.
+ *
* Historically, this file started life as "connection.c". However,
* it was renamed to "gateway.c" since its primary focus is gateway
* routes and gateway route management.
@@ -1864,8 +1869,6 @@ done:
* @retval -EPERM If the current process does not have the
* credentials or capabilities to unset, or
* clear, routes.
- * @retval -ESRCH A request was made to unset, or clear a
- * non-existing routing entry.
*
* @sa gateway_config_state_set
* @sa is_gateway_config_state
@@ -1892,8 +1895,27 @@ static int unset_default_gateway_route_common(struct gateway_data *data,
if (is_gateway_config_state_inactive(config))
return -EALREADY;
+ /*
+ * Generally, we mandate that gateway routes follow the documented
+ * lifecycle and state machine, using events and down- and upcalls
+ * to drive the lifecycle.
+ *
+ * There is one exception, however. When the Linux kernel
+ * recognizes that the next hop (that is, the "via" or RTA_GATEWAY
+ * part of the route) for a route becomes unreachable, it is
+ * automatically purged from the routing table with no
+ * RTM_DELROUTE RTNL notification. Consequently, routes so purged
+ * will return -ESRCH when we attempt to delete them here in the
+ * mistaken belief they are still there.
+ *
+ * Map -ESRCH to success such that gateway configuration for such
+ * routes is not indefinitely stuck in the "active" or "added"
+ * states.
+ */
err = cb(data, config);
- if (err < 0)
+ if (err == -ESRCH)
+ err = 0;
+ else if (err < 0)
goto done;
gateway_config_state_set(config,
This maps the error '-ESRCH' in 'unset_default_gateway_route_common' to 0 ("Success"). Generally, we mandate that gateway routes follow the documented lifecycle and finite state machine, using events and down- and upcalls to drive the lifecycle. There is one exception, however. When the Linux kernel recognizes that the next hop (that is, the "via" or RTA_GATEWAY portion of the route) for a route becomes unreachable, it is automatically purged from the routing table with no RTM_DELROUTE RTNL notification. Consequently, routes so purged will return -ESRCH when we attempt to delete them here in the mistaken belief they are still there. By mapping -ESRCH to 0 ("Success") we ensure that gateway configuration for such routes is not indefinitely stuck in the "active" or "added" states but rather is correctly advanced to the "removed" state. --- src/gateway.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-)