Merge pull request #22199 from yuwata/resolve-reduce-attempts-reading-networkd-link-file

resolve: reduce attempts of reading networkd's link file

src/shared/netif-util.c

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <linux/if.h>
 #include <linux/if_arp.h>
 
 #include "arphrd-util.h"
@@ -11,6 +12,20 @@
 #include "sparse-endian.h"
 #include "strv.h"
 
+bool netif_has_carrier(uint8_t operstate, unsigned flags) {
+        /* see Documentation/networking/operstates.txt in the kernel sources */
+
+        if (operstate == IF_OPER_UP)
+                return true;
+
+        if (operstate != IF_OPER_UNKNOWN)
+                return false;
+
+        /* operstate may not be implemented, so fall back to flags */
+        return FLAGS_SET(flags, IFF_LOWER_UP | IFF_RUNNING) &&
+                !FLAGS_SET(flags, IFF_DORMANT);
+}
+
 int net_get_type_string(sd_device *device, uint16_t iftype, char **ret) {
         const char *t;
         char *p;

src/shared/netif-util.h

@@ -9,6 +9,7 @@
 
 #include "ether-addr-util.h"
 
+bool netif_has_carrier(uint8_t operstate, unsigned flags);
 int net_get_type_string(sd_device *device, uint16_t iftype, char **ret);
 const char *net_get_persistent_name(sd_device *device);
 int net_get_unique_predictable_data(sd_device *device, bool use_sysname, uint64_t *ret);