platform: allow injecting the list of addresses to prune

Follow the pattern of nm_platform_ip_route_sync(), which also accepts
the list of addresses that are potential candidates for removal.

This allows the caller to carefully construct the list of addresses
which are possibly removed, so that sync (possibly) only adds new
addresses.

2 files changed, 53 insertions, 13 deletions

diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 4415aa84c1..25fa732cb1 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -3794,7 +3794,16 @@ ip6_address_scope_cmp (gconstpointer p_a, gconstpointer p_b, gpointer increasing
  *   telling which addresses were successfully added.
  *   Addresses are removed by unrefing the instance via nmp_object_unref()
  *   and leaving a NULL tombstone.
- * @full_sync: Also remove link-local and temporary addresses (IPv6 only).
+ * @addresses_prune: (allow-none): the list of addresses to delete.
+ *   If platform has such an address configured, it will be deleted
+ *   at the beginning of the sync. Note that the array will be modified
+ *   by the function.
+ *   Note that the addresses must be properly sorted, by their priority.
+ *   Create this list with nm_platform_ip_address_get_prune_list() which
+ *   gets the sorting right.
+ * @full_sync: Also remove temporary addresses (IPv6 only).
+ *   In general, only addresses from @addresses_prune will be removed. Setting
+ *   this to FALSE (for IPv6) limits that some addresses won't be removed.
  *
  * A convenience function to synchronize addresses for a specific interface
  * with the least possible disturbance. It simply removes addresses that are
@@ -3807,14 +3816,14 @@ nm_platform_ip_address_sync (NMPlatform *self,
                              int addr_family,
                              int ifindex,
                              GPtrArray *known_addresses,
+                             GPtrArray *addresses_prune,
                              gboolean full_sync)
 {
 	const gint32 now = nm_utils_get_monotonic_timestamp_sec ();
 	const gboolean IS_IPv4 = NM_IS_IPv4 (addr_family);
-	gs_unref_ptrarray GPtrArray *plat_addresses = NULL;
 	gs_unref_hashtable GHashTable *known_addresses_idx = NULL;
+	GPtrArray *plat_addresses;
 	GHashTable *known_subnets = NULL;
-	NMPLookup lookup;
 	guint32 ifa_flags;
 	guint i_plat;
 	guint i_know;
@@ -3835,15 +3844,11 @@ nm_platform_ip_address_sync (NMPlatform *self,
 	if (!_addr_array_clean_expired (addr_family, ifindex, known_addresses, now, &known_addresses_idx))
 		known_addresses = NULL;
 
-	/* @plat_addresses is in decreasing priority order (highest priority addresses first), contrary to
+	/* @plat_addresses must be sorted in decreasing priority order (highest priority addresses first), contrary to
 	 * @known_addresses which is in increasing priority order (lowest priority addresses first). */
-	plat_addresses = nm_platform_lookup_clone (self,
-	                                           nmp_lookup_init_object (&lookup,
-	                                                                   NMP_OBJECT_TYPE_IP_ADDRESS (IS_IPv4),
-	                                                                   ifindex),
-	                                           NULL, NULL);
+	plat_addresses = addresses_prune;
 
-	if (plat_addresses) {
+	if (nm_g_ptr_array_len (plat_addresses) > 0) {
 		/* Delete unknown addresses */
 		if (IS_IPv4) {
 			GHashTable *plat_subnets;
@@ -4155,6 +4160,21 @@ _err_inval_due_to_ipv6_tentative_pref_src (NMPlatform *self, const NMPObject *ob
 }
 
 GPtrArray *
+nm_platform_ip_address_get_prune_list (NMPlatform *self,
+                                       int addr_family,
+                                       int ifindex)
+{
+	NMPLookup lookup;
+
+	return nm_platform_lookup_clone (self,
+	                                 nmp_lookup_init_object (&lookup,
+	                                                         NMP_OBJECT_TYPE_IP_ADDRESS (NM_IS_IPv4 (addr_family)),
+	                                                         ifindex),
+	                                 NULL,
+	                                 NULL);
+}
+
+GPtrArray *
 nm_platform_ip_route_get_prune_list (NMPlatform *self,
                                      int addr_family,
                                      int ifindex,
diff --git a/src/platform/nm-platform.h b/src/platform/nm-platform.h
index 8247814140..a571960c03 100644
--- a/src/platform/nm-platform.h
+++ b/src/platform/nm-platform.h
@@ -1840,18 +1840,38 @@ gboolean nm_platform_ip6_address_add (NMPlatform *self,
 gboolean nm_platform_ip4_address_delete (NMPlatform *self, int ifindex, in_addr_t address, guint8 plen, in_addr_t peer_address);
 gboolean nm_platform_ip6_address_delete (NMPlatform *self, int ifindex, struct in6_addr address, guint8 plen);
 
-gboolean nm_platform_ip_address_sync (NMPlatform *self, int addr_family, int ifindex, GPtrArray *known_addresses, gboolean full_sync);
+gboolean nm_platform_ip_address_sync (NMPlatform *self,
+                                      int addr_family,
+                                      int ifindex,
+                                      GPtrArray *known_addresses,
+                                      GPtrArray *addresses_prune,
+                                      gboolean full_sync);
+
+GPtrArray *nm_platform_ip_address_get_prune_list (NMPlatform *self,
+                                                 int addr_family,
+                                                 int ifindex);
+
+static inline gboolean
+_nm_platform_ip_address_sync (NMPlatform *self, int addr_family, int ifindex, GPtrArray *known_addresses, gboolean full_sync)
+{
+	gs_unref_ptrarray GPtrArray *addresses_prune = NULL;
+
+	addresses_prune = nm_platform_ip_address_get_prune_list (self,
+	                                                         addr_family,
+	                                                         ifindex);
+	return nm_platform_ip_address_sync (self, addr_family, ifindex, known_addresses, addresses_prune, TRUE);
+}
 
 static inline gboolean
 nm_platform_ip4_address_sync (NMPlatform *self, int ifindex, GPtrArray *known_addresses)
 {
-	return nm_platform_ip_address_sync (self, AF_INET, ifindex, known_addresses, TRUE);
+	return _nm_platform_ip_address_sync (self, AF_INET, ifindex, known_addresses, TRUE);
 }
 
 static inline gboolean
 nm_platform_ip6_address_sync (NMPlatform *self, int ifindex, GPtrArray *known_addresses, gboolean full_sync)
 {
-	return nm_platform_ip_address_sync (self, AF_INET6, ifindex, known_addresses, full_sync);
+	return _nm_platform_ip_address_sync (self, AF_INET6, ifindex, known_addresses, full_sync);
 }
 
 gboolean nm_platform_ip_address_flush (NMPlatform *self,