network: introduce a tiny wrapper for manager_udev_process_link()

Preparation for later commits.

src/network/networkd-link.c

@@ -1488,21 +1488,13 @@ static int link_check_initialized(Link *link) {
         return link_initialized(link, device);
 }
 
-int manager_udev_process_link(sd_device_monitor *monitor, sd_device *device, void *userdata) {
-        sd_device_action_t action;
-        Manager *m = userdata;
-        Link *link = NULL;
+int manager_udev_process_link(Manager *m, sd_device *device, sd_device_action_t action) {
         int r, ifindex;
+        Link *link;
 
         assert(m);
         assert(device);
 
-        r = sd_device_get_action(device, &action);
-        if (r < 0) {
-                log_device_debug_errno(device, r, "Failed to get udev action, ignoring device: %m");
-                return 0;
-        }
-
         /* Ignore the "remove" uevent — let's remove a device only if rtnetlink says so. All other uevents
          * are "positive" events in some form, i.e. inform us about a changed or new network interface, that
          * still exists — and we are interested in that. */
@@ -1510,25 +1502,20 @@ int manager_udev_process_link(sd_device_monitor *monitor, sd_device *device, voi
                 return 0;
 
         r = sd_device_get_ifindex(device, &ifindex);
-        if (r < 0) {
-                log_device_debug_errno(device, r, "Ignoring udev %s event for device without ifindex or with invalid ifindex: %m",
-                                       device_action_to_string(action));
-                return 0;
-        }
+        if (r < 0)
+                return log_device_debug_errno(device, r, "Failed to get ifindex: %m");
 
         r = device_is_renaming(device);
-        if (r < 0) {
-                log_device_debug_errno(device, r, "Failed to determine the device is renamed or not, ignoring '%s' uevent: %m",
-                                       device_action_to_string(action));
-                return 0;
-        }
+        if (r < 0)
+                return log_device_debug_errno(device, r, "Failed to determine if the device is renaming or not: %m");
         if (r > 0) {
-                log_device_debug(device, "Interface is under renaming, wait for the interface to be renamed.");
+                log_device_debug(device, "Device is renaming, waiting for the interface to be renamed.");
                 return 0;
         }
 
         r = link_get_by_index(m, ifindex, &link);
         if (r < 0) {
+                /* This error is not critical, as the corresponding rtnl message may be received later. */
                 log_device_debug_errno(device, r, "Failed to get link from ifindex %i, ignoring: %m", ifindex);
                 return 0;
         }

src/network/networkd-link.h

@@ -235,7 +235,7 @@ LinkState link_state_from_string(const char *s) _pure_;
 int link_reconfigure(Link *link, bool force);
 int link_reconfigure_after_sleep(Link *link);
 
-int manager_udev_process_link(sd_device_monitor *monitor, sd_device *device, void *userdata);
+int manager_udev_process_link(Manager *m, sd_device *device, sd_device_action_t action);
 int manager_rtnl_process_link(sd_netlink *rtnl, sd_netlink_message *message, Manager *m);
 
 int link_flags_to_string_alloc(uint32_t flags, char **ret);

src/network/networkd-manager.c

@@ -18,6 +18,8 @@
 #include "bus-util.h"
 #include "conf-parser.h"
 #include "def.h"
+#include "device-private.h"
+#include "device-util.h"
 #include "dns-domain.h"
 #include "fd-util.h"
 #include "fileio.h"
@@ -168,6 +170,35 @@ static int manager_connect_bus(Manager *m) {
         return 0;
 }
 
+static int manager_process_uevent(sd_device_monitor *monitor, sd_device *device, void *userdata) {
+        Manager *m = ASSERT_PTR(userdata);
+        sd_device_action_t action;
+        const char *s;
+        int r;
+
+        assert(device);
+
+        r = sd_device_get_action(device, &action);
+        if (r < 0)
+                return log_device_warning_errno(device, r, "Failed to get udev action, ignoring: %m");
+
+        r = sd_device_get_subsystem(device, &s);
+        if (r < 0)
+                return log_device_warning_errno(device, r, "Failed to get subsystem, ignoring: %m");
+
+        if (streq(s, "net"))
+                r = manager_udev_process_link(m, device, action);
+        else {
+                log_device_debug(device, "Received device with unexpected subsystem \"%s\", ignoring.", s);
+                return 0;
+        }
+        if (r < 0)
+                log_device_warning_errno(device, r, "Failed to process \"%s\" uevent, ignoring: %m",
+                                         device_action_to_string(action));
+
+        return 0;
+}
+
 static int manager_connect_udev(Manager *m) {
         int r;
 
@@ -186,13 +217,13 @@ static int manager_connect_udev(Manager *m) {
 
         r = sd_device_monitor_filter_add_match_subsystem_devtype(m->device_monitor, "net", NULL);
         if (r < 0)
-                return log_error_errno(r, "Could not add device monitor filter: %m");
+                return log_error_errno(r, "Could not add device monitor filter for net subsystem: %m");
 
         r = sd_device_monitor_attach_event(m->device_monitor, m->event);
         if (r < 0)
                 return log_error_errno(r, "Failed to attach event to device monitor: %m");
 
-        r = sd_device_monitor_start(m->device_monitor, manager_udev_process_link, m);
+        r = sd_device_monitor_start(m->device_monitor, manager_process_uevent, m);
         if (r < 0)
                 return log_error_errno(r, "Failed to start device monitor: %m");