platform: fix IPv6 address sync after for link local addresses

Since commit 78ed0a4a23f2e08cf5f3a4c75c67eba877c66494 (device: add
IPv6 link local address via merge-and-apply) we handle also IPv6 link
local addresses like regular addresses. That is, we also add them during
merge-and-apply and sync them via nm_platform_ip6_address_sync().

ip6-address-sync loops over the platform addresses, to find which
addresses shall be deleted, and which shall be deleted in order to
fix the address order/priority. At that point, we must not ignore
link-local addresses anymore, but handle them too.

Otherwise, during each resync we have link local addresses, and
platform-sync thinks that the address order is wrong. That wrongly
leads to remove most addresses and re-adding them.

Fixes: 78ed0a4a23f2e08cf5f3a4c75c67eba877c66494

1 files changed, 6 insertions, 4 deletions

diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 976039def4..a5e2477a97 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -3652,8 +3652,11 @@ nm_platform_ip6_address_sync (NMPlatform *self,
 		 * If we don't find a matching valid address in @known_addresses, we will delete
 		 * plat_addr.
 		 *
-		 * Certain addresses, like link-local or temporary addresses, are ignored by this function
-		 * if not run with full_sync.
+		 * Certain addresses, like temporary addresses, are ignored by this function
+		 * if not run with full_sync. These addresses are usually not managed by NetworkManager
+		 * directly, or at least, they are not managed via nm_platform_ip6_address_sync().
+		 * Only in full_sync mode, we really want to get rid of them (usually, when we take
+		 * the interface down).
 		 *
 		 * Note that we mark handled addresses by setting it to %NULL in @plat_addresses array. */
 		for (i_plat = 0; i_plat < plat_addresses->len; i_plat++) {
@@ -3661,8 +3664,7 @@ nm_platform_ip6_address_sync (NMPlatform *self,
 			const NMPObject *know_obj;
 			const NMPlatformIP6Address *plat_addr = NMP_OBJECT_CAST_IP6_ADDRESS (plat_obj);
 
-			if (   NM_FLAGS_HAS (plat_addr->n_ifa_flags, IFA_F_TEMPORARY)
-			    || IN6_IS_ADDR_LINKLOCAL (&plat_addr->address)) {
+			if (NM_FLAGS_HAS (plat_addr->n_ifa_flags, IFA_F_TEMPORARY)) {
 				if (!full_sync) {
 					/* just mark as handled, without actually deleting the address. */
 					goto clear_and_next;