network: unref existing sd_ipv4acd object when not necessary

On reconfiguring an interface, the new setting may not enable IPv4ACD
for an existing address anymore. Hence, we need to unref it. Otherwise,
newly requested addresses may never be ready for (re-)configuring.

diff --git a/src/network/networkd-ipv4acd.c b/src/network/networkd-ipv4acd.c
index f55e998f233766b013bbf153ff8db47caf63bbcd..a6335754448ada7d477a1aa6947bdb788fa5dbb8 100644 (file)
--- a/src/network/networkd-ipv4acd.c
+++ b/src/network/networkd-ipv4acd.c
@@ -39,6 +39,26 @@ bool link_ipv4acd_supported(Link *link) {
         return true;
 }
 
+static bool address_ipv4acd_enabled(Address *address) {
+        assert(address);
+        assert(address->link);
+
+        if (address->family != AF_INET)
+                return false;
+
+        if (!FLAGS_SET(address->duplicate_address_detection, ADDRESS_FAMILY_IPV4))
+                return false;
+
+        /* Currently, only static and DHCP4 addresses are supported. */
+        if (!IN_SET(address->source, NETWORK_CONFIG_SOURCE_STATIC, NETWORK_CONFIG_SOURCE_DHCP4))
+                return false;
+
+        if (!link_ipv4acd_supported(address->link))
+                return false;
+
+        return true;
+}
+
 bool ipv4acd_bound(const Address *address) {
         assert(address);
 
@@ -188,17 +208,11 @@ int ipv4acd_configure(Address *address) {
 
         link = ASSERT_PTR(address->link);
 
-        if (address->family != AF_INET)
-                return 0;
-
-        if (!FLAGS_SET(address->duplicate_address_detection, ADDRESS_FAMILY_IPV4))
-                return 0;
-
-        if (!link_ipv4acd_supported(link))
+        if (!address_ipv4acd_enabled(address)) {
+                address->acd = sd_ipv4acd_unref(address->acd);
+                address->acd_bound = false;
                 return 0;
-
-        /* Currently, only static and DHCP4 addresses are supported. */
-        assert(IN_SET(address->source, NETWORK_CONFIG_SOURCE_STATIC, NETWORK_CONFIG_SOURCE_DHCP4));
+        }
 
         if (address->acd)
                 return address_ipv4acd_start(address);