platform,core: merge branch 'th/platform-rt-prefsrc'

https://bugzilla.redhat.com/show_bug.cgi?id=2046293

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1550

21 files changed, 1474 insertions, 630 deletions

diff --git a/.clang-format b/.clang-format
index 4099440415..fb100bb1cd 100644
--- a/.clang-format
+++ b/.clang-format
@@ -120,6 +120,7 @@ ForEachMacros: [
                 'nm_manager_for_each_device',
                 'nm_manager_for_each_device_safe',
                 'nm_platform_iter_obj_for_each',
+                'nm_prioq_for_each',
                 'nmp_cache_iter_for_each',
                 'nmp_cache_iter_for_each_link',
                 'nmp_cache_iter_for_each_reverse',
diff --git a/src/core/devices/nm-device.c b/src/core/devices/nm-device.c
index 939a9b2995..497108b1c1 100644
--- a/src/core/devices/nm-device.c
+++ b/src/core/devices/nm-device.c
@@ -3522,7 +3522,7 @@ _dev_ip_state_check(NMDevice *self, int addr_family)
                                 &s_is_pending,
                                 &s_is_failed);
 
-    has_tna = priv->l3cfg && nm_l3cfg_has_temp_not_available_obj(priv->l3cfg, addr_family);
+    has_tna = priv->l3cfg && nm_l3cfg_has_failedobj_pending(priv->l3cfg, addr_family);
     if (has_tna)
         s_is_pending = TRUE;
 
@@ -3967,9 +3967,7 @@ after_merge_flags:
 }
 
 static gboolean
-_dev_l3_register_l3cds_add_config(NMDevice          *self,
-                                  L3ConfigDataType   l3cd_type,
-                                  NML3CfgConfigFlags flags)
+_dev_l3_register_l3cds_add_config(NMDevice *self, L3ConfigDataType l3cd_type)
 {
     NMDevicePrivate     *priv = NM_DEVICE_GET_PRIVATE(self);
     NML3ConfigMergeFlags merge_flags;
@@ -3992,7 +3990,7 @@ _dev_l3_register_l3cds_add_config(NMDevice          *self,
                                _prop_get_ipvx_dns_priority(self, AF_INET6),
                                acd_defend_type,
                                acd_timeout_msec,
-                               flags,
+                               NM_L3CFG_CONFIG_FLAGS_NONE,
                                merge_flags);
 }
 
@@ -4000,7 +3998,6 @@ static gboolean
 _dev_l3_register_l3cds_set_one_full(NMDevice             *self,
                                     L3ConfigDataType      l3cd_type,
                                     const NML3ConfigData *l3cd,
-                                    NML3CfgConfigFlags    flags,
                                     NMTernary             commit_sync)
 {
     NMDevicePrivate                         *priv     = NM_DEVICE_GET_PRIVATE(self);
@@ -4024,7 +4021,7 @@ _dev_l3_register_l3cds_set_one_full(NMDevice             *self,
 
     if (priv->l3cfg) {
         if (priv->l3cds[l3cd_type].d) {
-            if (_dev_l3_register_l3cds_add_config(self, l3cd_type, flags))
+            if (_dev_l3_register_l3cds_add_config(self, l3cd_type))
                 changed = TRUE;
         }
 
@@ -4048,11 +4045,7 @@ _dev_l3_register_l3cds_set_one(NMDevice             *self,
                                const NML3ConfigData *l3cd,
                                NMTernary             commit_sync)
 {
-    return _dev_l3_register_l3cds_set_one_full(self,
-                                               l3cd_type,
-                                               l3cd,
-                                               NM_L3CFG_CONFIG_FLAGS_NONE,
-                                               commit_sync);
+    return _dev_l3_register_l3cds_set_one_full(self, l3cd_type, l3cd, commit_sync);
 }
 
 static void
@@ -4107,7 +4100,7 @@ _dev_l3_register_l3cds(NMDevice *self,
         }
         if (is_external)
             continue;
-        if (_dev_l3_register_l3cds_add_config(self, i, NM_L3CFG_CONFIG_FLAGS_NONE))
+        if (_dev_l3_register_l3cds_add_config(self, i))
             changed = TRUE;
     }
 
@@ -4261,6 +4254,7 @@ _dev_l3_cfg_notify_cb(NML3Cfg *l3cfg, const NML3ConfigNotifyData *notify_data, N
             _dev_ipshared4_spawn_dnsmasq(self);
             nm_clear_l3cd(&priv->ipshared_data_4.v4.l3cd);
         }
+        _dev_ip_state_check_async(self, AF_UNSPEC);
         _dev_ipmanual_check_ready(self);
         return;
     case NM_L3_CONFIG_NOTIFY_TYPE_IPV4LL_EVENT:
@@ -4270,10 +4264,6 @@ _dev_l3_cfg_notify_cb(NML3Cfg *l3cfg, const NML3ConfigNotifyData *notify_data, N
         return;
     case NM_L3_CONFIG_NOTIFY_TYPE_PLATFORM_CHANGE:
         return;
-    case NM_L3_CONFIG_NOTIFY_TYPE_ROUTES_TEMPORARY_NOT_AVAILABLE_EXPIRED:
-        /* we commit again. This way we try to configure the routes.*/
-        _dev_l3_cfg_commit(self, FALSE);
-        return;
     case NM_L3_CONFIG_NOTIFY_TYPE_PLATFORM_CHANGE_ON_IDLE:
         if (NM_FLAGS_ANY(notify_data->platform_change_on_idle.obj_type_flags,
                          nmp_object_type_to_flags(NMP_OBJECT_TYPE_LINK)
@@ -4305,9 +4295,6 @@ _dev_l3_cfg_notify_cb(NML3Cfg *l3cfg, const NML3ConfigNotifyData *notify_data, N
                  * synchronously to update the current state and schedule a commit. */
                 nm_ndisc_dad_failed(priv->ipac6_data.ndisc, conflicts, TRUE);
             } else if (ready) {
-                if (nm_l3cfg_has_temp_not_available_obj(priv->l3cfg, AF_INET6))
-                    _dev_l3_cfg_commit(self, FALSE);
-
                 nm_clear_l3cd(&priv->ipac6_data.l3cd);
                 _dev_ipac6_set_state(self, NM_DEVICE_IP_STATE_READY);
                 _dev_ip_state_check_async(self, AF_INET6);
@@ -10314,14 +10301,6 @@ _dev_ipmanual_check_ready(NMDevice *self)
             _dev_ipmanual_set_state(self, addr_family, NM_DEVICE_IP_STATE_FAILED);
             _dev_ip_state_check_async(self, AF_UNSPEC);
         } else if (ready) {
-            if (priv->ipmanual_data.state_x[IS_IPv4] != NM_DEVICE_IP_STATE_READY
-                && nm_l3cfg_has_temp_not_available_obj(priv->l3cfg, addr_family)) {
-                /* Addresses with pending ACD/DAD are a possible cause for the
-                 * presence of temporarily-not-available objects. Once all addresses
-                 * are ready, retry to commit those unavailable objects. */
-                _dev_l3_cfg_commit(self, FALSE);
-            }
-
             _dev_ipmanual_set_state(self, addr_family, NM_DEVICE_IP_STATE_READY);
             _dev_ip_state_check_async(self, AF_UNSPEC);
         }
@@ -10487,7 +10466,6 @@ _dev_ipdhcpx_notify(NMDhcpClient *client, const NMDhcpClientNotifyData *notify_d
         _dev_l3_register_l3cds_set_one_full(self,
                                             L3_CONFIG_DATA_TYPE_DHCP_X(IS_IPv4),
                                             notify_data->lease_update.l3cd,
-                                            NM_L3CFG_CONFIG_FLAGS_FORCE_ONCE,
                                             FALSE);
 
         if (notify_data->lease_update.accepted) {
@@ -10708,7 +10686,6 @@ _dev_ipdhcpx_start(NMDevice *self, int addr_family)
         _dev_l3_register_l3cds_set_one_full(self,
                                             L3_CONFIG_DATA_TYPE_DHCP_X(IS_IPv4),
                                             previous_lease,
-                                            NM_L3CFG_CONFIG_FLAGS_FORCE_ONCE,
                                             FALSE);
     }
 
@@ -11641,11 +11618,7 @@ _dev_ipac6_ndisc_config_changed(NMNDisc              *ndisc,
 
     _dev_ipac6_grace_period_start(self, 0, TRUE);
 
-    _dev_l3_register_l3cds_set_one_full(self,
-                                        L3_CONFIG_DATA_TYPE_AC_6,
-                                        l3cd,
-                                        NM_L3CFG_CONFIG_FLAGS_FORCE_ONCE,
-                                        FALSE);
+    _dev_l3_register_l3cds_set_one_full(self, L3_CONFIG_DATA_TYPE_AC_6, l3cd, FALSE);
 
     nm_clear_l3cd(&priv->ipac6_data.l3cd);
     ready = nm_l3cfg_check_ready(priv->l3cfg,
diff --git a/src/core/nm-l3-config-data.c b/src/core/nm-l3-config-data.c
index 17bb9db87d..4a9dd78bcf 100644
--- a/src/core/nm-l3-config-data.c
+++ b/src/core/nm-l3-config-data.c
@@ -2604,7 +2604,6 @@ nm_l3_config_data_add_dependent_device_routes(NML3ConfigData       *self,
                                               int                   addr_family,
                                               guint32               route_table,
                                               guint32               route_metric,
-                                              gboolean              force_commit,
                                               const NML3ConfigData *source)
 {
     const int          IS_IPv4 = NM_IS_IPv4(addr_family);
@@ -2649,7 +2648,6 @@ nm_l3_config_data_add_dependent_device_routes(NML3ConfigData       *self,
                                                                                     self->ifindex,
                                                                                     route_table,
                                                                                     route_metric,
-                                                                                    force_commit,
                                                                                     &r_stack.r4);
             if (r)
                 nm_l3_config_data_add_route(self, addr_family, NULL, r);
@@ -2685,13 +2683,12 @@ nm_l3_config_data_add_dependent_device_routes(NML3ConfigData       *self,
                 }
 
                 rx.r6 = (NMPlatformIP6Route){
-                    .ifindex        = self->ifindex,
-                    .rt_source      = NM_IP_CONFIG_SOURCE_KERNEL,
-                    .table_coerced  = nm_platform_route_table_coerce(route_table),
-                    .metric         = route_metric,
-                    .network        = *a6,
-                    .plen           = plen,
-                    .r_force_commit = force_commit,
+                    .ifindex       = self->ifindex,
+                    .rt_source     = NM_IP_CONFIG_SOURCE_KERNEL,
+                    .table_coerced = nm_platform_route_table_coerce(route_table),
+                    .metric        = route_metric,
+                    .network       = *a6,
+                    .plen          = plen,
                 };
 
                 nm_platform_ip_route_normalize(addr_family, &rx.rx);
@@ -3197,7 +3194,6 @@ nm_l3_config_data_merge(NML3ConfigData       *self,
             NMPlatformIPXAddress       a;
             NML3ConfigMergeHookResult  hook_result = {
                  .ip4acd_not_ready = NM_OPTION_BOOL_DEFAULT,
-                 .force_commit     = NM_OPTION_BOOL_DEFAULT,
             };
 
 #define _ensure_a()                                       \
@@ -3230,12 +3226,6 @@ nm_l3_config_data_merge(NML3ConfigData       *self,
                 a.a4.a_acd_not_ready = (!!hook_result.ip4acd_not_ready);
             }
 
-            if (hook_result.force_commit != NM_OPTION_BOOL_DEFAULT
-                && (!!hook_result.force_commit) != a_src->a_force_commit) {
-                _ensure_a();
-                a.ax.a_force_commit = (!!hook_result.force_commit);
-            }
-
             nm_l3_config_data_add_address_full(self,
                                                addr_family,
                                                a_src == &a.ax ? NULL : obj,
@@ -3255,7 +3245,6 @@ nm_l3_config_data_merge(NML3ConfigData       *self,
                 NMPlatformIPXRoute        r;
                 NML3ConfigMergeHookResult hook_result = {
                     .ip4acd_not_ready = NM_OPTION_BOOL_DEFAULT,
-                    .force_commit     = NM_OPTION_BOOL_DEFAULT,
                 };
 
 #define _ensure_r()                                     \
@@ -3281,12 +3270,6 @@ nm_l3_config_data_merge(NML3ConfigData       *self,
                     r.rx.ifindex = self->ifindex;
                 }
 
-                if (hook_result.force_commit != NM_OPTION_BOOL_DEFAULT
-                    && (!!hook_result.force_commit) != r_src->r_force_commit) {
-                    _ensure_r();
-                    r.rx.r_force_commit = (!!hook_result.force_commit);
-                }
-
                 if (!NM_FLAGS_HAS(merge_flags, NM_L3_CONFIG_MERGE_FLAGS_CLONE)) {
                     if (r_src->table_any) {
                         _ensure_r();
diff --git a/src/core/nm-l3-config-data.h b/src/core/nm-l3-config-data.h
index bfab04d9ce..80abb00d88 100644
--- a/src/core/nm-l3-config-data.h
+++ b/src/core/nm-l3-config-data.h
@@ -137,7 +137,6 @@ NML3ConfigData *nm_l3_config_data_new_from_platform(NMDedupMultiIndex        *mu
 
 typedef struct {
     NMOptionBool ip4acd_not_ready;
-    NMOptionBool force_commit;
 } NML3ConfigMergeHookResult;
 
 typedef gboolean (*NML3ConfigMergeHookAddObj)(const NML3ConfigData      *l3cd,
@@ -164,7 +163,6 @@ void nm_l3_config_data_add_dependent_device_routes(NML3ConfigData       *self,
                                                    int                   addr_family,
                                                    guint32               route_table,
                                                    guint32               route_metric,
-                                                   gboolean              force_commit,
                                                    const NML3ConfigData *source);
 
 /*****************************************************************************/
diff --git a/src/core/nm-l3cfg.c b/src/core/nm-l3cfg.c
index a49654feb5..4a49c4f8d9 100644
--- a/src/core/nm-l3cfg.c
+++ b/src/core/nm-l3cfg.c
@@ -11,6 +11,7 @@
 #include <linux/if_ether.h>
 #include <linux/rtnetlink.h>
 
+#include "libnm-glib-aux/nm-prioq.h"
 #include "libnm-glib-aux/nm-time-utils.h"
 #include "libnm-platform/nm-platform.h"
 #include "libnm-platform/nmp-object.h"
@@ -123,25 +124,34 @@ typedef struct {
 
     CList os_lst;
 
-    /* If we have a timeout pending, we link the instance to
-     * self->priv.p->obj_state_temporary_not_available_lst_head. */
-    CList os_temporary_not_available_lst;
-
     /* If a NMPObject is no longer to be configured (but was configured
      * during a previous commit), then we need to remember it so that the
      * next commit can delete the address/route in kernel. It becomes a zombie. */
     CList os_zombie_lst;
 
-    /* We might want to configure "obj" in platform, but it's currently not possible.
-     * For example, certain IPv6 routes can only be added after the IPv6 address
-     * becomes non-tentative (*sigh*). In such a case, we need to remember that, and
-     * retry later. If this timestamp is set to a non-zero value, then it means
-     * we tried to configure the obj (at that timestamp) and failed, but we are
-     * waiting to retry.
+    /* Used by _handle_routes_failed() mechanism. If "os_plobj" is set, then
+     * this is meaningless but should be set to zero.
+     *
+     * If set to a non-zero value, this means adding the object failed.  Until
+     * "os_failedobj_expiry_msec" we are still waiting whether we would be able to
+     * configure the object. Afterwards, we consider the element failed.
      *
-     * See also self->priv.p->obj_state_temporary_not_available_lst_head
-     * and self->priv.p->obj_state_temporary_not_available_timeout_source. */
-    gint64 os_temporary_not_available_timestamp_msec;
+     * Depending on "os_failedobj_prioq_idx", we are currently waiting whether the
+     * condition can resolve itself or becomes a failure. */
+    gint64 os_failedobj_expiry_msec;
+
+    /* The index into the "priv->failedobj_prioq" queue for objects that are failed.
+     * - this field is meaningless in case "os_plobj" is set (but it should be
+     *   set to NM_PRIOQ_IDX_NULL).
+     * - otherwise, if "os_failedobj_expiry_msec" is 0, no error was detected so
+     *   far. The index should be set to NM_PRIOQ_IDX_NULL.
+     * - otherwise, if the index is NM_PRIOQ_IDX_NULL it means that the object
+     *   is not tracked by the queue, no grace timer is pending, and the object
+     *   is considered failed.
+     * - otherwise, the index is used for tracking the element in the queue.
+     *   It means, we are currently waiting to decide whether this will be a
+     *   failure or not. */
+    guint os_failedobj_prioq_idx;
 
     /* When the obj is a zombie (that means, it was previously configured by NML3Cfg, but
      * now no longer), it needs to be deleted from platform. This ratelimits the time
@@ -206,7 +216,6 @@ typedef struct {
     guint32           acd_timeout_msec_confdata;
     NML3AcdDefendType acd_defend_type_confdata : 3;
     bool              dirty_confdata : 1;
-    gboolean          force_commit_once : 1;
 } L3ConfigData;
 
 struct _NML3CfgBlockHandle {
@@ -241,7 +250,6 @@ typedef struct _NML3CfgPrivate {
 
     CList obj_state_lst_head;
     CList obj_state_zombie_lst_head;
-    CList obj_state_temporary_not_available_lst_head;
 
     GHashTable *acd_ipv4_addresses_on_link;
 
@@ -288,12 +296,22 @@ typedef struct _NML3CfgPrivate {
 
     guint64 pseudo_timestamp_counter;
 
-    GSource *obj_state_temporary_not_available_timeout_source;
+    NMPrioq  failedobj_prioq;
+    GSource *failedobj_timeout_source;
+    gint64   failedobj_timeout_expiry_msec;
 
     NML3CfgCommitType commit_on_idle_type;
 
     gint8 commit_reentrant_count;
 
+    union {
+        struct {
+            gint8 commit_reentrant_count_ip_address_sync_6;
+            gint8 commit_reentrant_count_ip_address_sync_4;
+        };
+        gint8 commit_reentrant_count_ip_address_sync_x[2];
+    };
+
     /* The value that was set before we touched the sysctl (this only is
      * meaningful if "ip6_privacy_set" is true. At the end, we want to restore
      * this value. */
@@ -340,6 +358,9 @@ G_DEFINE_TYPE(NML3Cfg, nm_l3cfg, G_TYPE_OBJECT)
 
 #define _MPTCP_TAG(self, IS_IPv4) ((gconstpointer) (&(((const char *) (self))[2 + (!(IS_IPv4))])))
 
+#define _NETNS_WATCHER_IP_ADDR_TAG(self, addr_family) \
+    ((gconstpointer) & (((char *) self)[1 + NM_IS_IPv4(addr_family)]))
+
 /*****************************************************************************/
 
 #define _NMLOG_DOMAIN      LOGD_CORE
@@ -410,8 +431,6 @@ static NM_UTILS_ENUM2STR_DEFINE(
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_PLATFORM_CHANGE_ON_IDLE, "platform-change-on-idle"),
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_PRE_COMMIT, "pre-commit"),
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_POST_COMMIT, "post-commit"),
-    NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_ROUTES_TEMPORARY_NOT_AVAILABLE_EXPIRED,
-                      "routes-temporary-not-available-expired"),
     NM_UTILS_ENUM2STR_IGNORE(_NM_L3_CONFIG_NOTIFY_TYPE_NUM), );
 
 static NM_UTILS_ENUM2STR_DEFINE(_l3_acd_defend_type_to_string,
@@ -754,51 +773,51 @@ _nm_n_acd_data_probe_new(NML3Cfg *self, in_addr_t addr, guint32 timeout_msec, gp
 
 /*****************************************************************************/
 
-#define nm_assert_obj_state(self, obj_state)                                                      \
-    G_STMT_START                                                                                  \
-    {                                                                                             \
-        if (NM_MORE_ASSERTS > 0) {                                                                \
-            const NML3Cfg      *_self      = (self);                                              \
-            const ObjStateData *_obj_state = (obj_state);                                         \
-                                                                                                  \
-            nm_assert(_obj_state);                                                                \
-            nm_assert(NM_IN_SET(NMP_OBJECT_GET_TYPE(_obj_state->obj),                             \
-                                NMP_OBJECT_TYPE_IP4_ADDRESS,                                      \
-                                NMP_OBJECT_TYPE_IP6_ADDRESS,                                      \
-                                NMP_OBJECT_TYPE_IP4_ROUTE,                                        \
-                                NMP_OBJECT_TYPE_IP6_ROUTE));                                      \
-            nm_assert(!_obj_state->os_plobj || _obj_state->os_was_in_platform);                   \
-            nm_assert((_obj_state->os_temporary_not_available_timestamp_msec == 0)                \
-                      == c_list_is_empty(&_obj_state->os_temporary_not_available_lst));           \
-            if (_self) {                                                                          \
-                if (c_list_is_empty(&_obj_state->os_zombie_lst)) {                                \
-                    nm_assert(_self->priv.p->combined_l3cd_commited);                             \
-                                                                                                  \
-                    if (NM_MORE_ASSERTS > 5) {                                                    \
-                        nm_assert(c_list_contains(&_self->priv.p->obj_state_lst_head,             \
-                                                  &_obj_state->os_lst));                          \
-                        nm_assert((_obj_state->os_temporary_not_available_timestamp_msec == 0)    \
-                                  || c_list_contains(                                             \
-                                      &_self->priv.p->obj_state_temporary_not_available_lst_head, \
-                                      &_obj_state->os_temporary_not_available_lst));              \
-                        nm_assert(_obj_state->os_plobj                                            \
-                                  == nm_platform_lookup_obj(_self->priv.platform,                 \
-                                                            NMP_CACHE_ID_TYPE_OBJECT_TYPE,        \
-                                                            _obj_state->obj));                    \
-                        nm_assert(                                                                \
-                            c_list_is_empty(&obj_state->os_zombie_lst)                            \
-                                ? (_obj_state->obj                                                \
-                                   == nm_dedup_multi_entry_get_obj(nm_l3_config_data_lookup_obj(  \
-                                       _self->priv.p->combined_l3cd_commited,                     \
-                                       _obj_state->obj)))                                         \
-                                : (!nm_l3_config_data_lookup_obj(                                 \
-                                    _self->priv.p->combined_l3cd_commited,                        \
-                                    _obj_state->obj)));                                           \
-                    }                                                                             \
-                }                                                                                 \
-            }                                                                                     \
-        }                                                                                         \
-    }                                                                                             \
+#define nm_assert_obj_state(self, obj_state)                                                     \
+    G_STMT_START                                                                                 \
+    {                                                                                            \
+        if (NM_MORE_ASSERTS > 0) {                                                               \
+            const NML3Cfg      *_self      = (self);                                             \
+            const ObjStateData *_obj_state = (obj_state);                                        \
+                                                                                                 \
+            nm_assert(_obj_state);                                                               \
+            nm_assert(NM_IN_SET(NMP_OBJECT_GET_TYPE(_obj_state->obj),                            \
+                                NMP_OBJECT_TYPE_IP4_ADDRESS,                                     \
+                                NMP_OBJECT_TYPE_IP6_ADDRESS,                                     \
+                                NMP_OBJECT_TYPE_IP4_ROUTE,                                       \
+                                NMP_OBJECT_TYPE_IP6_ROUTE));                                     \
+            nm_assert(!_obj_state->os_plobj || _obj_state->os_was_in_platform);                  \
+            nm_assert(_obj_state->os_failedobj_expiry_msec != 0                                  \
+                      || _obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);               \
+            nm_assert(_obj_state->os_failedobj_expiry_msec == 0 || !_obj_state->os_plobj);       \
+            nm_assert(_obj_state->os_failedobj_expiry_msec == 0                                  \
+                      || c_list_is_empty(&_obj_state->os_zombie_lst));                           \
+            nm_assert(_obj_state->os_failedobj_expiry_msec == 0 || _obj_state->obj);             \
+            if (_self) {                                                                         \
+                if (c_list_is_empty(&_obj_state->os_zombie_lst)) {                               \
+                    nm_assert(_self->priv.p->combined_l3cd_commited);                            \
+                                                                                                 \
+                    if (NM_MORE_ASSERTS > 5) {                                                   \
+                        nm_assert(c_list_contains(&_self->priv.p->obj_state_lst_head,            \
+                                                  &_obj_state->os_lst));                         \
+                        nm_assert(_obj_state->os_plobj                                           \
+                                  == nm_platform_lookup_obj(_self->priv.platform,                \
+                                                            NMP_CACHE_ID_TYPE_OBJECT_TYPE,       \
+                                                            _obj_state->obj));                   \
+                        nm_assert(                                                               \
+                            c_list_is_empty(&obj_state->os_zombie_lst)                           \
+                                ? (_obj_state->obj                                               \
+                                   == nm_dedup_multi_entry_get_obj(nm_l3_config_data_lookup_obj( \
+                                       _self->priv.p->combined_l3cd_commited,                    \
+                                       _obj_state->obj)))                                        \
+                                : (!nm_l3_config_data_lookup_obj(                                \
+                                    _self->priv.p->combined_l3cd_commited,                       \
+                                    _obj_state->obj)));                                          \
+                    }                                                                            \
+                }                                                                                \
+            }                                                                                    \
+        }                                                                                        \
+    }                                                                                            \
     G_STMT_END
 
 static ObjStateData *
@@ -808,13 +827,14 @@ _obj_state_data_new(const NMPObject *obj, const NMPObject *plobj)
 
     obj_state  = g_slice_new(ObjStateData);
     *obj_state = (ObjStateData){
-        .obj                            = nmp_object_ref(obj),
-        .os_plobj                       = nmp_object_ref(plobj),
-        .os_was_in_platform             = !!plobj,
-        .os_nm_configured               = FALSE,
-        .os_dirty                       = FALSE,
-        .os_temporary_not_available_lst = C_LIST_INIT(obj_state->os_temporary_not_available_lst),
-        .os_zombie_lst                  = C_LIST_INIT(obj_state->os_zombie_lst),
+        .obj                      = nmp_object_ref(obj),
+        .os_plobj                 = nmp_object_ref(plobj),
+        .os_was_in_platform       = !!plobj,
+        .os_nm_configured         = FALSE,
+        .os_dirty                 = FALSE,
+        .os_failedobj_expiry_msec = 0,
+        .os_failedobj_prioq_idx   = NM_PRIOQ_IDX_NULL,
+        .os_zombie_lst            = C_LIST_INIT(obj_state->os_zombie_lst),
     };
     return obj_state;
 }
@@ -824,9 +844,10 @@ _obj_state_data_free(gpointer data)
 {
     ObjStateData *obj_state = data;
 
+    nm_assert(obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);
+
     c_list_unlink_stale(&obj_state->os_lst);
     c_list_unlink_stale(&obj_state->os_zombie_lst);
-    c_list_unlink_stale(&obj_state->os_temporary_not_available_lst);
     nmp_object_unref(obj_state->obj);
     nmp_object_unref(obj_state->os_plobj);
     nm_g_slice_free(obj_state);
@@ -864,15 +885,17 @@ _obj_state_data_to_string(const ObjStateData *obj_state, char *buf, gsize buf_si
     } else if (obj_state->os_was_in_platform)
         nm_strbuf_append_str(&buf, &buf_size, ", was-in-platform");
 
-    if (obj_state->os_temporary_not_available_timestamp_msec > 0) {
+    if (obj_state->os_failedobj_expiry_msec > 0) {
         nm_utils_get_monotonic_timestamp_msec_cached(&now_msec);
-        nm_strbuf_append(
-            &buf,
-            &buf_size,
-            ", temporary-not-available-since=%" G_GINT64_FORMAT ".%03d",
-            (now_msec - obj_state->os_temporary_not_available_timestamp_msec) / 1000,
-            (int) ((now_msec - obj_state->os_temporary_not_available_timestamp_msec) % 1000));
-    }
+        nm_strbuf_append(&buf,
+                         &buf_size,
+                         ", %s-since=%" G_GINT64_FORMAT ".%03d",
+                         (obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL) ? "failed"
+                                                                                  : "failed-wait",
+                         (obj_state->os_failedobj_expiry_msec - now_msec) / 1000,
+                         (int) ((obj_state->os_failedobj_expiry_msec - now_msec) % 1000));
+    } else
+        nm_assert(obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);
 
     return buf0;
 }
@@ -934,6 +957,7 @@ _obj_states_externally_removed_track(NML3Cfg *self, const NMPObject *obj, gboole
 
     if (!in_platform && !c_list_is_empty(&obj_state->os_zombie_lst)) {
         /* this is a zombie. We can forget about it.*/
+        nm_assert(obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);
         nm_clear_nmp_object(&obj_state->os_plobj);
         c_list_unlink(&obj_state->os_zombie_lst);
         _LOGD("obj-state: zombie gone (untrack): %s",
@@ -949,8 +973,23 @@ _obj_states_externally_removed_track(NML3Cfg *self, const NMPObject *obj, gboole
     if (in_platform) {
         nmp_object_ref_set(&obj_state->os_plobj, obj);
         obj_state->os_was_in_platform = TRUE;
-        _LOGD("obj-state: appeared in platform: %s",
-              _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)));
+        if (obj_state->os_failedobj_expiry_msec != 0) {
+            obj_state->os_failedobj_expiry_msec = 0;
+            if (obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL) {
+                _LOGT("obj-state: failed-obj: object now configured after failed earlier: %s",
+                      _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)));
+            } else {
+                nm_prioq_remove(&self->priv.p->failedobj_prioq,
+                                obj_state,
+                                &obj_state->os_failedobj_prioq_idx);
+                _LOGT("obj-state: failed-obj: object now configured after waiting: %s",
+                      _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)));
+            }
+        } else {
+            _LOGD("obj-state: appeared in platform: %s",
+                  _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)));
+        }
+        nm_assert(obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);
         goto out;
     }
 
@@ -1039,6 +1078,7 @@ _obj_states_update_all(NML3Cfg *self)
                 continue;
 
             if (obj_state->os_plobj && obj_state->os_nm_configured) {
+                nm_assert(obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);
                 c_list_link_tail(&self->priv.p->obj_state_zombie_lst_head,
                                  &obj_state->os_zombie_lst);
                 obj_state->os_zombie_count = ZOMBIE_COUNT_START;
@@ -1049,6 +1089,9 @@ _obj_states_update_all(NML3Cfg *self)
 
             _LOGD("obj-state: untrack: %s",
                   _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)));
+            nm_prioq_remove(&self->priv.p->failedobj_prioq,
+                            obj_state,
+                            &obj_state->os_failedobj_prioq_idx);
             g_hash_table_iter_remove(&h_iter);
         }
     }
@@ -1086,16 +1129,32 @@ _obj_states_sync_filter(NML3Cfg *self, const NMPObject *obj, NML3CfgCommitType c
         return TRUE;
     }
 
-    if (obj_state->os_temporary_not_available_timestamp_msec > 0) {
-        /* we currently try to configure this address (but failed earlier).
-         * Definitely retry. */
-        return TRUE;
-    }
-
-    if (!obj_state->os_plobj && commit_type != NM_L3_CFG_COMMIT_TYPE_REAPPLY
-        && !nmp_object_get_force_commit(obj))
-        return FALSE;
-
+    /* One goal would be that we don't forcefully re-add routes which were
+     * externally removed (e.g. by the user via `ip route del`).
+     *
+     * However,
+     *
+     *  - some routes get automatically deleted by kernel (for example,
+     *  when we have an IPv4 route with RTA_PREFSRC set and the referenced
+     *  IPv4 address gets removed). The absence of such a route does not
+     *  mean that the user doesn't want the route there. It means, kernel
+     *  removed it because of some consistency check, but we want it back.
+     *  - a route with a non-zero gateway requires that the gateway is
+     *  directly reachable via an onlink route. The rules for this are
+     *  complex, but kernel will reject adding a route which has such a
+     *  gateway. If the user manually removed the needed onlink route, the
+     *  gateway route cannot be added in kernel ("Nexthop has invalid
+     *  gateway"). To handle that is a nightmare, so we always ensure that
+     *  the onlink route is there.
+     *  - a route with RTA_PREFSRC requires that such an address is
+     *  configured otherwise kernel rejects adding the route with "Invalid
+     *  prefsrc address"/"Invalid source address".  Removing an address can
+     *  thus prevent adding the route, which is a problem for us.
+     *
+     * So the goal is not tenable and causes problems. NetworkManager will
+     * try hard to re-add routes and address that it thinks should be
+     * present. If you externally remove them, then you are starting a
+     * fight where NetworkManager tries to re-add them on every commit. */
     return TRUE;
 }
 
@@ -1246,6 +1305,7 @@ _obj_state_zombie_lst_get_prune_lists(NML3Cfg    *self,
         if (--obj_state->os_zombie_count == 0) {
             _LOGD("obj-state: prune zombie (untrack): %s",
                   _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)));
+            nm_assert(obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);
             g_hash_table_remove(self->priv.p->obj_state_hash, obj_state);
             continue;
         }
@@ -1280,6 +1340,7 @@ _obj_state_zombie_lst_prune_all(NML3Cfg *self, int addr_family)
         if (--obj_state->os_zombie_count == 0) {
             _LOGD("obj-state: zombie pruned during reapply (untrack): %s",
                   _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)));
+            nm_assert(obj_state->os_failedobj_prioq_idx == NM_PRIOQ_IDX_NULL);
             g_hash_table_remove(self->priv.p->obj_state_hash, obj_state);
             continue;
         }
@@ -3017,16 +3078,14 @@ nm_l3cfg_get_acd_addr_info(NML3Cfg *self, in_addr_t addr)
 /*****************************************************************************/
 
 gboolean
-nm_l3cfg_has_temp_not_available_obj(NML3Cfg *self, int addr_family)
+nm_l3cfg_has_failedobj_pending(NML3Cfg *self, int addr_family)
 {
     ObjStateData *obj_state;
 
     nm_assert(NM_IS_L3CFG(self));
     nm_assert_addr_family(addr_family);
 
-    c_list_for_each_entry (obj_state,
-                           &self->priv.p->obj_state_temporary_not_available_lst_head,
-                           os_temporary_not_available_lst) {
+    nm_prioq_for_each (&self->priv.p->failedobj_prioq, obj_state) {
         if (NMP_OBJECT_GET_ADDR_FAMILY(obj_state->obj) == addr_family)
             return TRUE;
     }
@@ -3413,8 +3472,7 @@ nm_l3cfg_add_config(NML3Cfg              *self,
             .acd_timeout_msec_confdata = acd_timeout_msec,
             .priority_confdata         = priority,
             .pseudo_timestamp_confdata = ++self->priv.p->pseudo_timestamp_counter,
-            .force_commit_once = NM_FLAGS_HAS(config_flags, NM_L3CFG_CONFIG_FLAGS_FORCE_ONCE),
-            .dirty_confdata    = FALSE,
+            .dirty_confdata            = FALSE,
         };
         changed = TRUE;
     } else {
@@ -3611,7 +3669,6 @@ typedef struct {
     NML3Cfg      *self;
     gconstpointer tag;
     bool          to_commit;
-    bool          force_commit_once;
 } L3ConfigMergeHookAddObjData;
 
 static gboolean
@@ -3629,9 +3686,6 @@ _l3_hook_add_obj_cb(const NML3ConfigData      *l3cd,
     nm_assert(obj);
     nm_assert(hook_result);
     nm_assert(hook_result->ip4acd_not_ready == NM_OPTION_BOOL_DEFAULT);
-    nm_assert(hook_result->force_commit == NM_OPTION_BOOL_DEFAULT);
-
-    hook_result->force_commit = hook_data->force_commit_once;
 
     switch (NMP_OBJECT_GET_TYPE(obj)) {
     case NMP_OBJECT_TYPE_IP4_ADDRESS:
@@ -3787,8 +3841,7 @@ _l3cfg_update_combined_config(NML3Cfg               *self,
             if (NM_FLAGS_HAS(l3cd_data->config_flags, NM_L3CFG_CONFIG_FLAGS_ONLY_FOR_ACD))
                 continue;
 
-            hook_data.tag               = l3cd_data->tag_confdata;
-            hook_data.force_commit_once = l3cd_data->force_commit_once;
+            hook_data.tag = l3cd_data->tag_confdata;
 
             nm_l3_config_data_merge(l3cd,
                                     l3cd_data->l3cd,
@@ -3846,7 +3899,6 @@ _l3cfg_update_combined_config(NML3Cfg               *self,
                     IS_IPv4 ? AF_INET : AF_INET6,
                     l3cd_data->default_route_table_x[IS_IPv4],
                     l3cd_data->default_route_metric_x[IS_IPv4],
-                    l3cd_data->force_commit_once,
                     l3cd_data->l3cd);
             }
         }
@@ -3921,79 +3973,91 @@ out:
 /*****************************************************************************/
 
 static gboolean
-_routes_temporary_not_available_timeout(gpointer user_data)
+_failedobj_timeout_cb(gpointer user_data)
 {
-    NML3Cfg      *self = NM_L3CFG(user_data);
-    ObjStateData *obj_state;
-    gint64        now_msec;
-    gint64        expiry_msec;
+    NML3Cfg *self = NM_L3CFG(user_data);
 
-    nm_clear_g_source_inst(&self->priv.p->obj_state_temporary_not_available_timeout_source);
+    _LOGT("obj-state: failed-obj: handle timeout");
 
-    obj_state = c_list_first_entry(&self->priv.p->obj_state_temporary_not_available_lst_head,
-                                   ObjStateData,
-                                   os_temporary_not_available_lst);
+    nm_clear_g_source_inst(&self->priv.p->failedobj_timeout_source);
 
-    if (!obj_state)
-        return G_SOURCE_CONTINUE;
+    nm_l3cfg_commit_on_idle_schedule(self, NM_L3_CFG_COMMIT_TYPE_AUTO);
+
+    return G_SOURCE_CONTINUE;
+}
 
-    now_msec = nm_utils_get_monotonic_timestamp_msec();
+static void
+_failedobj_reschedule(NML3Cfg *self, gint64 now_msec)
+{
+    char          sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+    ObjStateData *obj_state;
 
-    expiry_msec = obj_state->os_temporary_not_available_timestamp_msec
-                  + ROUTES_TEMPORARY_NOT_AVAILABLE_MAX_AGE_MSEC;
+    nm_utils_get_monotonic_timestamp_msec_cached(&now_msec);
 
-    if (now_msec < expiry_msec) {
-        /* the timeout is not yet reached. Restart the timer... */
-        self->priv.p->obj_state_temporary_not_available_timeout_source =
-            nm_g_timeout_add_source(expiry_msec - now_msec,
-                                    _routes_temporary_not_available_timeout,
-                                    self);
-        return G_SOURCE_CONTINUE;
+again:
+    obj_state = nm_prioq_peek(&self->priv.p->failedobj_prioq);
+
+    if (obj_state && obj_state->os_failedobj_expiry_msec <= now_msec) {
+        /* The object is already expired... */
+
+        /* we shouldn't have a "os_plobj", because if we had, we should have
+         * removed "obj_state" from the queue. */
+        nm_assert(!obj_state->os_plobj);
+
+        /* we need to have an "obj", otherwise the "obj_state" instance
+         * shouldn't exist (as it also has not "os_plobj"). */
+        nm_assert(obj_state->obj);
+
+        /* It seems that nm_platform_ip_route_sync() signaled success and did
+         * not report the route as missing. Regardless, it is still not
+         * configured and the timeout expired. */
+        nm_prioq_remove(&self->priv.p->failedobj_prioq,
+                        obj_state,
+                        &obj_state->os_failedobj_prioq_idx);
+        _LOGW(
+            "missing IPv%c route: %s",
+            nm_utils_addr_family_to_char(NMP_OBJECT_GET_TYPE(obj_state->obj)),
+            nmp_object_to_string(obj_state->obj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
+        goto again;
     }
 
-    /* One (or several) routes expired. We emit a signal, but we don't schedule it again.
-     * We expect the callers to commit again, which will one last time try to configure
-     * the route. If that again fails, we detect the timeout, log a warning and don't
-     * track the object as not temporary-not-available anymore. */
-    _nm_l3cfg_emit_signal_notify_simple(
-        self,
-        NM_L3_CONFIG_NOTIFY_TYPE_ROUTES_TEMPORARY_NOT_AVAILABLE_EXPIRED);
-    return G_SOURCE_CONTINUE;
+    if (!obj_state) {
+        if (nm_clear_g_source_inst(&self->priv.p->failedobj_timeout_source))
+            _LOGT("obj-state: failed-obj: cancel timeout");
+        return;
+    }
+
+    if (nm_g_timeout_reschedule(&self->priv.p->failedobj_timeout_source,
+                                &self->priv.p->failedobj_timeout_expiry_msec,
+                                obj_state->os_failedobj_expiry_msec,
+                                _failedobj_timeout_cb,
+                                self)) {
+        _LOGT(
+            "obj-state: failed-obj: schedule timeout in %" G_GINT64_FORMAT " msec",
+            NM_MAX((gint64) 0,
+                   obj_state->os_failedobj_expiry_msec - nm_utils_get_monotonic_timestamp_msec()));
+    }
 }
 
-static gboolean
-_routes_temporary_not_available_update(NML3Cfg   *self,
-                                       int        addr_family,
-                                       GPtrArray *routes_temporary_not_available_arr)
+static void
+_failedobj_handle_routes(NML3Cfg *self, int addr_family, GPtrArray *routes_failed)
 {
-    ObjStateData   *obj_state;
-    ObjStateData   *obj_state_safe;
-    gint64          now_msec;
-    gboolean        prune_all = FALSE;
-    gboolean        success   = TRUE;
-    guint           i;
-    const NMPClass *klass;
-
-    klass    = nmp_class_from_type(NMP_OBJECT_TYPE_IP_ROUTE(NM_IS_IPv4(addr_family)));
-    now_msec = nm_utils_get_monotonic_timestamp_msec();
-
-    if (nm_g_ptr_array_len(routes_temporary_not_available_arr) <= 0) {
-        prune_all = TRUE;
-        goto out_prune;
-    }
+    const gint64  now_msec = nm_utils_get_monotonic_timestamp_msec();
+    char          sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+    ObjStateData *obj_state;
+    guint         i;
 
-    c_list_for_each_entry (obj_state,
-                           &self->priv.p->obj_state_temporary_not_available_lst_head,
-                           os_temporary_not_available_lst) {
-        if (NMP_OBJECT_GET_CLASS(obj_state->obj) == klass) {
-            nm_assert(obj_state->os_temporary_not_available_timestamp_msec > 0);
-            obj_state->os_tna_dirty = TRUE;
-        }
-    }
+    if (!routes_failed)
+        return;
 
-    for (i = 0; i < routes_temporary_not_available_arr->len; i++) {
-        const NMPObject *o = routes_temporary_not_available_arr->pdata[i];
-        char             sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+    for (i = 0; i < routes_failed->len; i++) {
+        const NMPObject          *o                    = routes_failed->pdata[i];
+        const NMPlatformIPXRoute *rt                   = NMP_OBJECT_CAST_IPX_ROUTE(o);
+        gboolean                  just_started_to_fail = FALSE;
+        gboolean                  just_failed          = FALSE;
+        gboolean                  arm_timer            = FALSE;
+        int                       grace_timeout_msec;
+        gint64                    grace_expiry_mesc;
 
         nm_assert(NMP_OBJECT_GET_TYPE(o) == NMP_OBJECT_TYPE_IP_ROUTE(NM_IS_IPv4(addr_family)));
 
@@ -4005,70 +4069,83 @@ _routes_temporary_not_available_update(NML3Cfg   *self,
             continue;
         }
 
-        if (obj_state->os_temporary_not_available_timestamp_msec > 0) {
-            nm_assert(obj_state->os_temporary_not_available_timestamp_msec > 0
-                      && obj_state->os_temporary_not_available_timestamp_msec <= now_msec);
-
-            if (!obj_state->os_tna_dirty) {
-                /* Odd, this only can happen if routes_temporary_not_available_arr contains duplicates.
-                 * It should not. */
-                nm_assert_not_reached();
-                continue;
-            }
-
-            if (now_msec > obj_state->os_temporary_not_available_timestamp_msec
-                               + ROUTES_TEMPORARY_NOT_AVAILABLE_MAX_AGE_MSEC) {
-                /* Timeout. Could not add this address.
-                 *
-                 * For now, keep it obj_state->os_tna_dirty and prune it below. */
-                _LOGW("failure to add IPv%c route: %s",
-                      nm_utils_addr_family_to_char(addr_family),
-                      nmp_object_to_string(o, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
-                success = FALSE;
-                continue;
-            }
-
-            obj_state->os_tna_dirty = FALSE;
+        if (obj_state->os_plobj) {
+            /* This object is apparently present in platform. Not sure what this failure report
+             * is about. Probably some harmless glitch. Ignore. */
             continue;
         }
 
-        _LOGT("(temporarily) unable to add IPv%c route: %s",
-              nm_utils_addr_family_to_char(addr_family),
-              nmp_object_to_string(o, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
+        /* This route failed, but why? That determines the grace time that we
+         * give before considering it bad. */
+        if (!nm_ip_addr_is_null(addr_family,
+                                nm_platform_ip_route_get_pref_src(addr_family, &rt->rx))) {
+            /* This route has a pref_src. A common cause for being unable to
+             * configure such routes, is that the referenced IP address is not
+             * configured/ready (yet). Give a longer timeout to this case. */
+            grace_timeout_msec = 10000;
+        } else {
+            /* Other route don't have any grace time. There is no retry/wait,
+             * they are a failure right away. */
+            grace_timeout_msec = 0;
+        }
 
-        obj_state->os_tna_dirty                              = FALSE;
-        obj_state->os_temporary_not_available_timestamp_msec = now_msec;
-        c_list_link_tail(&self->priv.p->obj_state_temporary_not_available_lst_head,
-                         &obj_state->os_temporary_not_available_lst);
-    }
+        grace_expiry_mesc = now_msec + grace_timeout_msec;
 
-out_prune:
-    c_list_for_each_entry_safe (obj_state,
-                                obj_state_safe,
-                                &self->priv.p->obj_state_temporary_not_available_lst_head,
-                                os_temporary_not_available_lst) {
-        if (prune_all || obj_state->os_tna_dirty) {
-            if (NMP_OBJECT_GET_CLASS(obj_state->obj) == klass) {
-                obj_state->os_temporary_not_available_timestamp_msec = 0;
-                c_list_unlink(&obj_state->os_temporary_not_available_lst);
+        if (obj_state->os_failedobj_expiry_msec == 0) {
+            /* This is a new failure that we didn't see before... */
+            obj_state->os_failedobj_expiry_msec = grace_expiry_mesc;
+            if (grace_timeout_msec == 0)
+                just_failed = TRUE;
+            else {
+                arm_timer            = TRUE;
+                just_started_to_fail = TRUE;
+            }
+        } else {
+            if (obj_state->os_failedobj_expiry_msec > grace_expiry_mesc) {
+                /* Shorten the grace timeout. We anyway rearm below... */
+                obj_state->os_failedobj_expiry_msec = grace_expiry_mesc;
             }
+            if (obj_state->os_failedobj_expiry_msec <= now_msec) {
+                /* The grace period is (already) expired. */
+                if (obj_state->os_failedobj_prioq_idx != NM_PRIOQ_IDX_NULL) {
+                    /* We are still tracking the element. It just is about to become failed. */
+                    just_failed = TRUE;
+                }
+            } else
+                arm_timer = TRUE;
         }
-    }
 
-    nm_clear_g_source_inst(&self->priv.p->obj_state_temporary_not_available_timeout_source);
-
-    obj_state = c_list_first_entry(&self->priv.p->obj_state_temporary_not_available_lst_head,
-                                   ObjStateData,
-                                   os_temporary_not_available_lst);
-    if (obj_state) {
-        self->priv.p->obj_state_temporary_not_available_timeout_source =
-            nm_g_timeout_add_source((obj_state->os_temporary_not_available_timestamp_msec
-                                     + ROUTES_TEMPORARY_NOT_AVAILABLE_MAX_AGE_MSEC - now_msec),
-                                    _routes_temporary_not_available_timeout,
-                                    self);
+        nm_prioq_update(&self->priv.p->failedobj_prioq,
+                        obj_state,
+                        &obj_state->os_failedobj_prioq_idx,
+                        arm_timer);
+
+        if (just_failed) {
+            _LOGW("unable to configure IPv%c route: %s",
+                  nm_utils_addr_family_to_char(addr_family),
+                  nmp_object_to_string(o, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
+        } else if (just_started_to_fail) {
+            _LOGT("obj-state: failed-obj: unable to configure %s. Wait for %d msec",
+                  _obj_state_data_to_string(obj_state, sbuf, sizeof(sbuf)),
+                  grace_timeout_msec);
+        }
     }
+}
 
-    return success;
+static int
+_failedobj_prioq_cmp(gconstpointer a, gconstpointer b)
+{
+    const ObjStateData *object_state_a = a;
+    const ObjStateData *object_state_b = b;
+
+    nm_assert(object_state_a);
+    nm_assert(object_state_a->os_failedobj_expiry_msec > 0);
+    nm_assert(object_state_b);
+    nm_assert(object_state_b->os_failedobj_expiry_msec > 0);
+
+    NM_CMP_SELF(object_state_a, object_state_b);
+    NM_CMP_FIELD(object_state_a, object_state_b, os_failedobj_expiry_msec);
+    return 0;
 }
 
 /*****************************************************************************/
@@ -4391,6 +4468,147 @@ _rp_filter_update(NML3Cfg *self, gboolean reapply)
 
 /*****************************************************************************/
 
+static void
+_routes_watch_ip_addrs_cb(NMNetns                       *netns,
+                          NMNetnsWatcherType             watcher_type,
+                          const NMNetnsWatcherData      *watcher_data,
+                          gconstpointer                  tag,
+                          const NMNetnsWatcherEventData *event_data,
+                          gpointer                       user_data)
+{
+    const int IS_IPv4 = NM_IS_IPv4(watcher_data->ip_addr.addr.addr_family);
+    NML3Cfg  *self    = user_data;
+    char      sbuf[NM_INET_ADDRSTRLEN];
+
+    if (NMP_OBJECT_CAST_IP_ADDRESS(event_data->ip_addr.obj)->ifindex == self->priv.ifindex) {
+        if (self->priv.p->commit_reentrant_count_ip_address_sync_x[IS_IPv4] > 0) {
+            /* We are currently commiting IP addresses on this very interface.
+             * We can ignore the event. Also, because we will sync the routes
+             * immediately after already.  So even if somebody externally added
+             * the address just this very moment, we would still do the commit
+             * at the right time to ensure our routes are there. */
+            return;
+        }
+    }
+
+    if (event_data->ip_addr.change_type == NM_PLATFORM_SIGNAL_REMOVED)
+        return;
+
+    _LOGT("watched ip-address %s changed. Schedule an idle commit",
+          nm_inet_ntop(watcher_data->ip_addr.addr.addr_family,
+                       &watcher_data->ip_addr.addr.addr,
+                       sbuf));
+    nm_l3cfg_commit_on_idle_schedule(self, NM_L3_CFG_COMMIT_TYPE_AUTO);
+}
+
+static void
+_routes_watch_ip_addrs(NML3Cfg *self, int addr_family, GPtrArray *addresses, GPtrArray *routes)
+{
+    gconstpointer const TAG          = _NETNS_WATCHER_IP_ADDR_TAG(self, addr_family);
+    NMNetnsWatcherData  watcher_data = {
+         .ip_addr =
+            {
+                 .addr =
+                    {
+                         .addr_family = addr_family,
+                    },
+            },
+    };
+    guint i;
+    guint j;
+
+    /* IP routes that have a pref_src, can only be configured in kernel if that
+     * address exists (and is non-tentative, in case of IPv6).  That address
+     * might be on another interface. So we actually watch all other
+     * interfaces.
+     *
+     * Note that while we track failure to configure routes via "failedobj"
+     * mechanism, we eagerly register watchers, even if the route is already
+     * successfully configured or if the route is to be configure the first
+     * time.  Maybe that could be improved, but
+     * - watchers should be cheap unless they notify the event.
+     * - upon change we do an async commit, which is maybe not entirely cheap
+     *   but cheap enough. More importantly, committing is something that
+     *   *always* should be permissible -- because NML3Cfg has multiple,
+     *   independent users, that don't know about each other and which
+     *   independently are allowed to issue a commit when they think something
+     *   relevant changed. If there are really too many, unnecessary commits,
+     *   then the cause needs to be understood and addressed explicitly. */
+
+    if (!routes)
+        goto out;
+
+    for (i = 0; i < routes->len; i++) {
+        const NMPlatformIPRoute *rt = NMP_OBJECT_CAST_IP_ROUTE(routes->pdata[i]);
+        gconstpointer            pref_src;
+
+        nm_assert(NMP_OBJECT_GET_ADDR_FAMILY(routes->pdata[i]) == addr_family);
+
+        pref_src = nm_platform_ip_route_get_pref_src(addr_family, rt);
+
+        if (nm_ip_addr_is_null(addr_family, pref_src))
+            continue;
+
+        if (NM_IS_IPv4(addr_family)) {
+            if (addresses) {
+                /* This nested loop makes the whole operation O(n*m). We still
+                 * do it that way, because it's probably faster to just iterate
+                 * over the few addresses instead of building a lookup index to
+                 * get it in O(n+m). */
+                for (j = 0; j < addresses->len; j++) {
+                    const NMPlatformIPAddress *a = NMP_OBJECT_CAST_IP_ADDRESS(addresses->pdata[j]);
+
+                    nm_assert(NMP_OBJECT_GET_ADDR_FAMILY(addresses->pdata[j]) == addr_family);
+
+                    if (nm_ip_addr_equal(addr_family, pref_src, a->address_ptr)) {
+                        /* We optimize for the case where the required address
+                         * is about be configured in the same commit. That is a
+                         * common case, because our DHCP routes have prefsrc
+                         * set, and we commonly have the respective IP address
+                         * ready.  Otherwise, the very common DHCP case would
+                         * also require the overhead of registering a watcher
+                         * (every time).
+                         */
+                        goto next;
+                    }
+                }
+            }
+        } else {
+            /* For IPv6, the prefsrc address must also be non-tentative (or
+             * IFA_F_OPTIMISTIC).  So by only looking at the addresses we are
+             * about to configure, it's not clear whether we will be able to
+             * configure the route too.
+             *
+             * Maybe we could check current platform, whether the address
+             * exists there as non-tentative, but that seems fragile.
+             *
+             * Maybe we should only register watchers, after we encountered a
+             * failure to configure a route, but that seems complicated (and
+             * has the potential to be wrong).
+             *
+             * The overhead for always watching the IPv6 address should be
+             * acceptably small. So just do that.
+             */
+        }
+
+        nm_assert(watcher_data.ip_addr.addr.addr_family == addr_family);
+        nm_ip_addr_set(addr_family, &watcher_data.ip_addr.addr.addr, pref_src);
+
+        nm_netns_watcher_add(self->priv.netns,
+                             NM_NETNS_WATCHER_TYPE_IP_ADDR,
+                             &watcher_data,
+                             TAG,
+                             _routes_watch_ip_addrs_cb,
+                             self);
+next:
+        (void) 0;
+    }
+
+out:
+    nm_netns_watcher_remove_all(self->priv.netns, TAG, FALSE);
+}
+/*****************************************************************************/
+
 static gboolean
 _global_tracker_mptcp_untrack(NML3Cfg *self, int addr_family)
 {
@@ -4576,24 +4794,22 @@ _l3_commit_mptcp(NML3Cfg *self, NML3CfgCommitType commit_type)
     _rp_filter_update(self, reapply);
 }
 
-static gboolean
+static void
 _l3_commit_one(NML3Cfg              *self,
                int                   addr_family,
                NML3CfgCommitType     commit_type,
                gboolean              changed_combined_l3cd,
                const NML3ConfigData *l3cd_old)
 {
-    const int                    IS_IPv4                            = NM_IS_IPv4(addr_family);
-    gs_unref_ptrarray GPtrArray *addresses                          = NULL;
-    gs_unref_ptrarray GPtrArray *routes                             = NULL;
-    gs_unref_ptrarray GPtrArray *routes_nodev                       = NULL;
-    gs_unref_ptrarray GPtrArray *addresses_prune                    = NULL;
-    gs_unref_ptrarray GPtrArray *routes_prune                       = NULL;
-    gs_unref_ptrarray GPtrArray *routes_temporary_not_available_arr = NULL;
+    const int                    IS_IPv4         = NM_IS_IPv4(addr_family);
+    gs_unref_ptrarray GPtrArray *addresses       = NULL;
+    gs_unref_ptrarray GPtrArray *routes          = NULL;
+    gs_unref_ptrarray GPtrArray *routes_nodev    = NULL;
+    gs_unref_ptrarray GPtrArray *addresses_prune = NULL;
+    gs_unref_ptrarray GPtrArray *routes_prune    = NULL;
+    gs_unref_ptrarray GPtrArray *routes_failed   = NULL;
     NMIPRouteTableSyncMode       route_table_sync;
-    gboolean                     final_failure_for_temporary_not_available = FALSE;
     char                         sbuf_commit_type[50];
-    gboolean                     success = TRUE;
     guint                        i;
 
     nm_assert(NM_IS_L3CFG(self));
@@ -4689,9 +4905,14 @@ _l3_commit_one(NML3Cfg              *self,
             }
         }
     }
+
+    _routes_watch_ip_addrs(self, addr_family, addresses, routes);
+
     /* FIXME(l3cfg): need to honor and set nm_l3_config_data_get_ndisc_*(). */
     /* FIXME(l3cfg): need to honor and set nm_l3_config_data_get_mtu(). */
 
+    self->priv.p->commit_reentrant_count_ip_address_sync_x[IS_IPv4]++;
+
     nm_platform_ip_address_sync(self->priv.platform,
                                 addr_family,
                                 self->priv.ifindex,
@@ -4701,26 +4922,18 @@ _l3_commit_one(NML3Cfg              *self,
                                     ? NMP_IP_ADDRESS_SYNC_FLAGS_NONE
                                     : NMP_IP_ADDRESS_SYNC_FLAGS_WITH_NOPREFIXROUTE);
 
-    _nodev_routes_sync(self, addr_family, commit_type, routes_nodev);
-
-    if (!nm_platform_ip_route_sync(self->priv.platform,
-                                   addr_family,
-                                   self->priv.ifindex,
-                                   routes,
-                                   routes_prune,
-                                   &routes_temporary_not_available_arr))
-        success = FALSE;
+    self->priv.p->commit_reentrant_count_ip_address_sync_x[IS_IPv4]--;
 
-    final_failure_for_temporary_not_available = FALSE;
-    if (!_routes_temporary_not_available_update(self,
-                                                addr_family,
-                                                routes_temporary_not_available_arr))
-        final_failure_for_temporary_not_available = TRUE;
+    _nodev_routes_sync(self, addr_family, commit_type, routes_nodev);
 
-    /* FIXME(l3cfg) */
-    (void) final_failure_for_temporary_not_available;
+    nm_platform_ip_route_sync(self->priv.platform,
+                              addr_family,
+                              self->priv.ifindex,
+                              routes,
+                              routes_prune,
+                              &routes_failed);
 
-    return success;
+    _failedobj_handle_routes(self, addr_family, routes_failed);
 }
 
 static void
@@ -4733,7 +4946,6 @@ _l3_commit(NML3Cfg *self, NML3CfgCommitType commit_type, gboolean is_idle)
     gboolean                                 is_sticky_update      = FALSE;
     char                                     sbuf_ct[30];
     gboolean                                 changed_combined_l3cd;
-    guint                                    i;
 
     g_return_if_fail(NM_IS_L3CFG(self));
     nm_assert(NM_IN_SET(commit_type,
@@ -4794,19 +5006,12 @@ _l3_commit(NML3Cfg *self, NML3CfgCommitType commit_type, gboolean is_idle)
     _l3_commit_one(self, AF_INET, commit_type, changed_combined_l3cd, l3cd_old);
     _l3_commit_one(self, AF_INET6, commit_type, changed_combined_l3cd, l3cd_old);
 
+    _failedobj_reschedule(self, 0);
+
     _l3_commit_mptcp(self, commit_type);
 
     _l3_acd_data_process_changes(self);
 
-    if (self->priv.p->l3_config_datas) {
-        for (i = 0; i < self->priv.p->l3_config_datas->len; i++) {
-            L3ConfigData *l3_config_data = _l3_config_datas_at(self->priv.p->l3_config_datas, i);
-
-            if (l3_config_data->force_commit_once)
-                l3_config_data->force_commit_once = FALSE;
-        }
-    }
-
     nm_assert(self->priv.p->commit_reentrant_count == 1);
     self->priv.p->commit_reentrant_count--;
 
@@ -5164,7 +5369,6 @@ nm_l3cfg_init(NML3Cfg *self)
     c_list_init(&self->priv.p->acd_event_notify_lst_head);
     c_list_init(&self->priv.p->commit_type_lst_head);
     c_list_init(&self->priv.p->obj_state_lst_head);
-    c_list_init(&self->priv.p->obj_state_temporary_not_available_lst_head);
     c_list_init(&self->priv.p->obj_state_zombie_lst_head);
     c_list_init(&self->priv.p->blocked_lst_head_4);
     c_list_init(&self->priv.p->blocked_lst_head_6);
@@ -5176,6 +5380,8 @@ nm_l3cfg_init(NML3Cfg *self)
                                                          nmp_object_indirect_id_equal,
                                                          _obj_state_data_free,
                                                          NULL);
+
+    nm_prioq_init(&self->priv.p->failedobj_prioq, _failedobj_prioq_cmp);
 }
 
 static void
@@ -5214,6 +5420,18 @@ finalize(GObject *object)
     NML3Cfg *self = NM_L3CFG(object);
     gboolean changed;
 
+    if (self->priv.netns) {
+        nm_netns_watcher_remove_all(self->priv.netns,
+                                    _NETNS_WATCHER_IP_ADDR_TAG(self, AF_INET),
+                                    TRUE);
+        nm_netns_watcher_remove_all(self->priv.netns,
+                                    _NETNS_WATCHER_IP_ADDR_TAG(self, AF_INET6),
+                                    TRUE);
+    }
+
+    nm_prioq_destroy(&self->priv.p->failedobj_prioq);
+    nm_clear_g_source_inst(&self->priv.p->failedobj_timeout_source);
+
     nm_assert(c_list_is_empty(&self->internal_netns.signal_pending_lst));
     nm_assert(c_list_is_empty(&self->internal_netns.ecmp_track_ifindex_lst_head));
 
@@ -5241,11 +5459,8 @@ finalize(GObject *object)
     nm_clear_g_source_inst(&self->priv.p->nacd_instance_ensure_retry);
     nm_clear_g_source_inst(&self->priv.p->nacd_event_down_source);
 
-    nm_clear_g_source_inst(&self->priv.p->obj_state_temporary_not_available_timeout_source);
-
     nm_clear_pointer(&self->priv.p->obj_state_hash, g_hash_table_destroy);
     nm_assert(c_list_is_empty(&self->priv.p->obj_state_lst_head));
-    nm_assert(c_list_is_empty(&self->priv.p->obj_state_temporary_not_available_lst_head));
     nm_assert(c_list_is_empty(&self->priv.p->obj_state_zombie_lst_head));
 
     if (_nodev_routes_untrack(self, AF_INET))
diff --git a/src/core/nm-l3cfg.h b/src/core/nm-l3cfg.h
index 9d622b4a01..5ee201e7a2 100644
--- a/src/core/nm-l3cfg.h
+++ b/src/core/nm-l3cfg.h
@@ -55,15 +55,11 @@ typedef enum _nm_packed {
  *   "don't change" behavior. At least once. If the address/route
  *   is still not (no longer) configured on the subsequent
  *   commit, it's not getting added again.
- * @NM_L3CFG_CONFIG_FLAGS_FORCE_ONCE: if set, objects in the
- *   NML3ConfigData are committed to platform even if they were
- *   removed externally.
  */
 typedef enum _nm_packed {
     NM_L3CFG_CONFIG_FLAGS_NONE               = 0,
     NM_L3CFG_CONFIG_FLAGS_ONLY_FOR_ACD       = (1LL << 0),
     NM_L3CFG_CONFIG_FLAGS_ASSUME_CONFIG_ONCE = (1LL << 1),
-    NM_L3CFG_CONFIG_FLAGS_FORCE_ONCE         = (1LL << 2),
 } NML3CfgConfigFlags;
 
 typedef enum _nm_packed {
@@ -132,8 +128,6 @@ typedef enum {
      * and neither should you call into NML3Cfg again (reentrancy). */
     NM_L3_CONFIG_NOTIFY_TYPE_L3CD_CHANGED,
 
-    NM_L3_CONFIG_NOTIFY_TYPE_ROUTES_TEMPORARY_NOT_AVAILABLE_EXPIRED,
-
     NM_L3_CONFIG_NOTIFY_TYPE_ACD_EVENT,
 
     /* emitted before the merged l3cd is committed to platform.
@@ -412,7 +406,7 @@ gboolean nm_l3cfg_check_ready(NML3Cfg               *self,
                               NML3CfgCheckReadyFlags flags,
                               GArray               **conflicts);
 
-gboolean nm_l3cfg_has_temp_not_available_obj(NML3Cfg *self, int addr_family);
+gboolean nm_l3cfg_has_failedobj_pending(NML3Cfg *self, int addr_family);
 
 /*****************************************************************************/
 
diff --git a/src/core/nm-netns.c b/src/core/nm-netns.c
index 88a4d66001..ad156f99ed 100644
--- a/src/core/nm-netns.c
+++ b/src/core/nm-netns.c
@@ -22,6 +22,44 @@
 
 /*****************************************************************************/
 
+typedef struct {
+    gconstpointer tag;
+    CList         watcher_by_tag_lst_head;
+} WatcherByTag;
+
+typedef struct {
+    NMIPAddrTyped addr;
+    CList         watcher_ip_addr_lst_head;
+} WatcherDataIPAddr;
+
+struct _NMNetnsWatcherHandle {
+    NMNetnsWatcherType     watcher_type;
+    NMNetnsWatcherData     watcher_data;
+    gconstpointer          tag;
+    NMNetnsWatcherCallback callback;
+    gpointer               callback_user_data;
+
+    /* This is linked to "WatcherByTag.watcher_by_tag_lst_head" in
+     * "priv->watcher_by_tag_idx". */
+    CList watcher_tag_lst;
+
+    /* The registration data, which depends on the "watcher_type". */
+    union {
+        struct {
+            CList watcher_ip_addr_lst;
+        } ip_addr;
+    } reg_data;
+
+    /* nm_netns_watcher_add() will mark the handle as non-dirty, while
+     * nm_netns_watcher_remove_all() can delete only dirty handles (while
+     * leaving non-dirty handles alive, but marking them as dirty).
+     *
+     * That allows a pattern where you just add the new handles that you want
+     * now, and then call nm_netns_watcher_remove_all() to remove those that
+     * should no longer be present. */
+    bool watcher_dirty : 1;
+};
+
 NM_GOBJECT_PROPERTIES_DEFINE_BASE(PROP_PLATFORM, );
 
 typedef struct {
@@ -33,8 +71,20 @@ typedef struct {
     GHashTable       *shared_ips;
     GHashTable       *ecmp_track_by_obj;
     GHashTable       *ecmp_track_by_ecmpid;
-    CList             l3cfg_signal_pending_lst_head;
-    GSource          *signal_pending_idle_source;
+
+    /* Indexes the watcher handles. */
+    GHashTable *watcher_idx;
+
+    /* An index of WatcherByTag. It allows to lookup watcher handles by tag.
+     * Handles without tag are not indexed. */
+    GHashTable *watcher_by_tag_idx;
+
+    /* Index for WatcherDataIPAddr instances. Allows to lookup all subscribers
+     * by IP address. */
+    GHashTable *watcher_ip_data_idx;
+
+    CList    l3cfg_signal_pending_lst_head;
+    GSource *signal_pending_idle_source;
 } NMNetnsPrivate;
 
 struct _NMNetns {
@@ -87,6 +137,24 @@ NM_DEFINE_SINGLETON_GETTER(NMNetns, nm_netns_get, NM_TYPE_NETNS);
 
 /*****************************************************************************/
 
+static WatcherDataIPAddr             *
+_watcher_ip_data_lookup(NMNetns *self, int addr_family, gconstpointer addr);
+static void _watcher_handle_notify(NMNetns                       *self,
+                                   NMNetnsWatcherHandle          *handle,
+                                   const NMNetnsWatcherEventData *event_data);
+static const char *
+_watcher_handle_to_string(const NMNetnsWatcherHandle *handle, char *buf, gsize buf_size);
+
+/*****************************************************************************/
+
+static gboolean
+NM_NETNS_WATCHER_TYPE_VALID(NMNetnsWatcherType watcher_type)
+{
+    return NM_IN_SET(watcher_type, NM_NETNS_WATCHER_TYPE_IP_ADDR);
+}
+
+/*****************************************************************************/
+
 typedef struct {
     const NMPObject *representative_obj;
     const NMPObject *merged_obj;
@@ -437,7 +505,7 @@ _platform_signal_cb(NMPlatform   *platform,
 
     l3cfg = nm_netns_l3cfg_get(self, ifindex);
     if (!l3cfg)
-        return;
+        goto notify_watcher;
 
     l3cfg->internal_netns.signal_pending_obj_type_flags |= nmp_object_type_to_flags(obj_type);
 
@@ -450,6 +518,55 @@ _platform_signal_cb(NMPlatform   *platform,
     }
 
     _nm_l3cfg_notify_platform_change(l3cfg, change_type, NMP_OBJECT_UP_CAST(platform_object));
+
+notify_watcher:
+    switch (obj_type) {
+    case NMP_OBJECT_TYPE_IP4_ADDRESS:
+    case NMP_OBJECT_TYPE_IP6_ADDRESS:
+    {
+        NMNetnsWatcherHandle *handle;
+        NMNetnsWatcherHandle *handle_safe;
+        WatcherDataIPAddr    *data;
+
+        data =
+            _watcher_ip_data_lookup(self,
+                                    obj_type == NMP_OBJECT_TYPE_IP4_ADDRESS ? AF_INET : AF_INET6,
+                                    ((const NMPlatformIPAddress *) platform_object)->address_ptr);
+
+        if (data) {
+            const NMNetnsWatcherEventData event_data = {
+                .ip_addr =
+                    {
+                        .change_type = change_type,
+                        .obj         = NMP_OBJECT_UP_CAST(platform_object),
+                    },
+            };
+            char sbuf[500];
+
+            c_list_for_each_entry_safe (handle,
+                                        handle_safe,
+                                        &data->watcher_ip_addr_lst_head,
+                                        reg_data.ip_addr.watcher_ip_addr_lst) {
+                _LOGT("netns-watcher: %s %s",
+                      "notify",
+                      _watcher_handle_to_string(handle, sbuf, sizeof(sbuf)));
+
+                /* Note that we dispatch these events directly from the platform event
+                 * and while iterating over "data".
+                 *
+                 * From the callback, it's probably a bad idea to do anything in platform
+                 * that might change anything (emit new signals) or to nm_netns_watcher_remove*()
+                 * any other watcher.
+                 *
+                 * The callee needs to be careful. */
+                _watcher_handle_notify(self, handle, &event_data);
+            }
+        }
+        break;
+    }
+    default:
+        break;
+    }
 }
 
 /*****************************************************************************/
@@ -823,6 +940,460 @@ nm_netns_ip_route_ecmp_commit(NMNetns    *self,
 /*****************************************************************************/
 
 static void
+_watcher_data_set(NMNetnsWatcherData       *dst,
+                  NMNetnsWatcherType        watcher_type,
+                  const NMNetnsWatcherData *src)
+{
+    nm_assert(dst);
+    nm_assert(src);
+
+    switch (watcher_type) {
+    case NM_NETNS_WATCHER_TYPE_IP_ADDR:
+        dst->ip_addr = src->ip_addr;
+        return;
+    }
+    nm_assert_not_reached();
+}
+
+static void
+_watcher_data_hash(NMHashState *h, NMNetnsWatcherType watcher_type, const NMNetnsWatcherData *data)
+{
+    nm_assert(h);
+    nm_assert(NM_NETNS_WATCHER_TYPE_VALID(watcher_type));
+    nm_assert(data);
+
+    switch (watcher_type) {
+    case NM_NETNS_WATCHER_TYPE_IP_ADDR:
+        nm_ip_addr_typed_hash_update(h, &data->ip_addr.addr);
+        return;
+    }
+    nm_assert_not_reached();
+}
+
+static gboolean
+_watcher_data_equal(NMNetnsWatcherType        watcher_type,
+                    const NMNetnsWatcherData *a,
+                    const NMNetnsWatcherData *b)
+{
+    nm_assert(NM_NETNS_WATCHER_TYPE_VALID(watcher_type));
+    nm_assert(a);
+    nm_assert(b);
+
+    switch (watcher_type) {
+    case NM_NETNS_WATCHER_TYPE_IP_ADDR:
+        return nm_ip_addr_typed_equal(&a->ip_addr.addr, &b->ip_addr.addr);
+    }
+    return nm_assert_unreachable_val(FALSE);
+}
+
+static void
+_watcher_by_tag_destroy(WatcherByTag *watcher_by_tag)
+{
+    c_list_unlink_stale(&watcher_by_tag->watcher_by_tag_lst_head);
+    nm_g_slice_free(watcher_by_tag);
+}
+
+static void
+_watcher_handle_init(NMNetnsWatcherHandle     *handle,
+                     NMNetnsWatcherType        watcher_type,
+                     const NMNetnsWatcherData *watcher_data,
+                     gconstpointer             tag)
+{
+    nm_assert(handle);
+    nm_assert(NM_NETNS_WATCHER_TYPE_VALID(watcher_type));
+
+    *handle = (NMNetnsWatcherHandle){
+        .watcher_type    = watcher_type,
+        .tag             = tag,
+        .watcher_tag_lst = C_LIST_INIT(handle->watcher_tag_lst),
+    };
+    _watcher_data_set(&handle->watcher_data, watcher_type, watcher_data);
+}
+
+static guint
+_watcher_handle_hash(gconstpointer data)
+{
+    const NMNetnsWatcherHandle *watcher = data;
+    NMHashState                 h;
+
+    nm_assert(watcher);
+    nm_assert(watcher->tag);
+
+    nm_hash_init(&h, 2696278447u);
+    nm_hash_update_vals(&h, watcher->tag, watcher->watcher_type);
+    _watcher_data_hash(&h, watcher->watcher_type, &watcher->watcher_data);
+    return nm_hash_complete(&h);
+}
+
+static gboolean
+_watcher_handle_equal(gconstpointer a, gconstpointer b)
+{
+    const NMNetnsWatcherHandle *ha = a;
+    const NMNetnsWatcherHandle *hb = b;
+
+    nm_assert(ha);
+    nm_assert(hb);
+    nm_assert(ha->tag);
+    nm_assert(hb->tag);
+
+    if (ha == hb)
+        return TRUE;
+
+    return (ha->tag == hb->tag) && (ha->watcher_type == hb->watcher_type)
+           && _watcher_data_equal(ha->watcher_type, &ha->watcher_data, &hb->watcher_data);
+}
+
+static const char *
+_watcher_handle_to_string(const NMNetnsWatcherHandle *handle, char *buf, gsize buf_size)
+{
+    const char *buf0 = buf;
+    char        sbuf[NM_INET_ADDRSTRLEN];
+
+    nm_strbuf_append(&buf,
+                     &buf_size,
+                     "h:" NM_HASH_OBFUSCATE_PTR_FMT "[",
+                     NM_HASH_OBFUSCATE_PTR(handle));
+
+    if (handle->tag) {
+        nm_strbuf_append(&buf,
+                         &buf_size,
+                         "tag:" NM_HASH_OBFUSCATE_PTR_FMT ",",
+                         NM_HASH_OBFUSCATE_PTR(handle->tag));
+    }
+
+    switch (handle->watcher_type) {
+    case NM_NETNS_WATCHER_TYPE_IP_ADDR:
+        nm_strbuf_append_str(&buf, &buf_size, "ip-addr:");
+        nm_strbuf_append_str(&buf,
+                             &buf_size,
+                             nm_inet_ntop(handle->watcher_data.ip_addr.addr.addr_family,
+                                          &handle->watcher_data.ip_addr.addr.addr,
+                                          sbuf));
+        goto out;
+    }
+    nm_assert_not_reached();
+    nm_strbuf_append_str(&buf, &buf_size, "unknown");
+
+out:
+    nm_strbuf_append_c(&buf, &buf_size, ']');
+    return buf0;
+}
+
+static void
+_watcher_handle_notify(NMNetns                       *self,
+                       NMNetnsWatcherHandle          *handle,
+                       const NMNetnsWatcherEventData *event_data)
+{
+    nm_assert(NM_IS_NETNS(self));
+    nm_assert(handle);
+    nm_assert(handle->callback);
+
+    handle->callback(self,
+                     handle->watcher_type,
+                     &handle->watcher_data,
+                     handle->tag,
+                     event_data,
+                     handle->callback_user_data);
+}
+
+static WatcherDataIPAddr *
+_watcher_ip_data_lookup(NMNetns *self, int addr_family, gconstpointer addr)
+{
+    WatcherDataIPAddr needle;
+
+    needle.addr.addr_family = addr_family;
+    nm_ip_addr_set(addr_family, &needle.addr.addr, addr);
+    return g_hash_table_lookup(NM_NETNS_GET_PRIVATE(self)->watcher_ip_data_idx, &needle);
+}
+
+static WatcherDataIPAddr *
+_watcher_ip_data_lookup_addr(NMNetns *self, const NMIPAddrTyped *addr)
+{
+    return _watcher_ip_data_lookup(self, addr->addr_family, &addr->addr);
+}
+
+static guint
+_watcher_ip_data_hash(gconstpointer _data)
+{
+    const WatcherDataIPAddr *data = _data;
+    NMHashState              h;
+
+    nm_assert(data);
+
+    nm_hash_init(&h, 3152126191u);
+    nm_ip_addr_typed_hash_update(&h, &data->addr);
+    return nm_hash_complete(&h);
+}
+
+static gboolean
+_watcher_ip_data_equal(gconstpointer a, gconstpointer b)
+{
+    const WatcherDataIPAddr *data_a = a;
+    const WatcherDataIPAddr *data_b = b;
+
+    nm_assert(data_a);
+    nm_assert(data_b);
+
+    return nm_ip_addr_typed_equal(&data_a->addr, &data_b->addr);
+}
+
+static NMNetnsWatcherHandle *
+_watcher_lookup_handle(NMNetns                  *self,
+                       NMNetnsWatcherType        watcher_type,
+                       const NMNetnsWatcherData *watcher_data,
+                       gconstpointer             tag)
+{
+    NMNetnsWatcherHandle handle_needle;
+
+    nm_assert(NM_IS_NETNS(self));
+    nm_assert(tag);
+
+    _watcher_handle_init(&handle_needle, watcher_type, watcher_data, tag);
+    return g_hash_table_lookup(NM_NETNS_GET_PRIVATE(self)->watcher_idx, &handle_needle);
+}
+
+static void
+_watcher_register_handle(NMNetns *self, NMNetnsWatcherHandle *handle)
+{
+    NMNetnsPrivate *priv = NM_NETNS_GET_PRIVATE(self);
+
+    switch (handle->watcher_type) {
+    case NM_NETNS_WATCHER_TYPE_IP_ADDR:
+    {
+        WatcherDataIPAddr *data;
+
+        data = _watcher_ip_data_lookup_addr(self, &handle->watcher_data.ip_addr.addr);
+        if (!data) {
+            data  = g_slice_new(WatcherDataIPAddr);
+            *data = (WatcherDataIPAddr){
+                .addr                     = handle->watcher_data.ip_addr.addr,
+                .watcher_ip_addr_lst_head = C_LIST_INIT(data->watcher_ip_addr_lst_head),
+            };
+            if (!g_hash_table_add(priv->watcher_ip_data_idx, data))
+                nm_assert_not_reached();
+        }
+
+        c_list_link_tail(&data->watcher_ip_addr_lst_head,
+                         &handle->reg_data.ip_addr.watcher_ip_addr_lst);
+        return;
+    }
+    }
+    nm_assert_not_reached();
+}
+
+static void
+_watcher_unregister_handle(NMNetns *self, NMNetnsWatcherHandle *handle)
+{
+    NMNetnsPrivate *priv = NM_NETNS_GET_PRIVATE(self);
+
+    switch (handle->watcher_type) {
+    case NM_NETNS_WATCHER_TYPE_IP_ADDR:
+    {
+        gboolean is_last;
+
+        nm_assert(({
+            WatcherDataIPAddr *d;
+
+            d = _watcher_ip_data_lookup_addr(self, &handle->watcher_data.ip_addr.addr);
+            d &&c_list_contains(&d->watcher_ip_addr_lst_head,
+                                &handle->reg_data.ip_addr.watcher_ip_addr_lst);
+        }));
+
+        is_last = c_list_is_empty_or_single(&handle->reg_data.ip_addr.watcher_ip_addr_lst);
+
+        c_list_unlink(&handle->reg_data.ip_addr.watcher_ip_addr_lst);
+
+        if (is_last) {
+            WatcherDataIPAddr *data;
+
+            data = _watcher_ip_data_lookup_addr(self, &handle->watcher_data.ip_addr.addr);
+            nm_assert(data);
+            nm_assert(c_list_is_empty(&data->watcher_ip_addr_lst_head));
+
+            if (!g_hash_table_remove(priv->watcher_ip_data_idx, data))
+                nm_assert_not_reached();
+
+            nm_g_slice_free(data);
+        }
+        return;
+    }
+    }
+    nm_assert_not_reached();
+}
+
+void
+nm_netns_watcher_add(NMNetns                  *self,
+                     NMNetnsWatcherType        watcher_type,
+                     const NMNetnsWatcherData *watcher_data,
+                     gconstpointer             tag,
+                     NMNetnsWatcherCallback    callback,
+                     gpointer                  user_data)
+{
+    NMNetnsPrivate       *priv;
+    NMNetnsWatcherHandle *handle;
+    gboolean              is_new = FALSE;
+    char                  sbuf[500];
+
+    g_return_if_fail(NM_IS_NETNS(self));
+    g_return_if_fail(NM_NETNS_WATCHER_TYPE_VALID(watcher_type));
+    g_return_if_fail(callback);
+    g_return_if_fail(tag);
+
+    priv = NM_NETNS_GET_PRIVATE(self);
+
+    handle = _watcher_lookup_handle(self, watcher_type, watcher_data, tag);
+
+    if (!handle) {
+        WatcherByTag *watcher_by_tag;
+
+        if (G_UNLIKELY(g_hash_table_size(priv->watcher_idx) == 0))
+            g_object_ref(self);
+
+        handle = g_slice_new(NMNetnsWatcherHandle);
+        _watcher_handle_init(handle, watcher_type, watcher_data, tag);
+
+        if (!g_hash_table_add(priv->watcher_idx, handle))
+            nm_assert_not_reached();
+
+        watcher_by_tag = g_hash_table_lookup(priv->watcher_by_tag_idx, &tag);
+
+        if (!watcher_by_tag) {
+            watcher_by_tag  = g_slice_new(WatcherByTag);
+            *watcher_by_tag = (WatcherByTag){
+                .tag                     = tag,
+                .watcher_by_tag_lst_head = C_LIST_INIT(watcher_by_tag->watcher_by_tag_lst_head),
+            };
+            g_hash_table_add(priv->watcher_by_tag_idx, watcher_by_tag);
+        }
+
+        c_list_link_tail(&watcher_by_tag->watcher_by_tag_lst_head, &handle->watcher_tag_lst);
+
+        is_new = TRUE;
+    } else {
+        /* Handles are deduplicated/shared. Hence it is error prone (and likely
+         * a bug) to provide different callback/user_data. Such usage is
+         * rejected here.
+         *
+         * This could be made to work, for example by now allowing handles to
+         * be merged or simply requiring the caller to be careful to not get
+         * this wrong. But that is currently not implemented nor needed.
+         */
+        nm_assert(!tag
+                  || (handle->callback == callback && handle->callback_user_data == user_data));
+    }
+
+    if (_LOGT_ENABLED()
+        && (is_new || handle->callback != callback || handle->callback_user_data != user_data)) {
+        _LOGT("netns-watcher: %s %s",
+              is_new ? "register" : "update",
+              _watcher_handle_to_string(handle, sbuf, sizeof(sbuf)));
+    }
+
+    handle->callback           = callback;
+    handle->callback_user_data = user_data;
+    handle->watcher_dirty      = FALSE;
+
+    if (is_new)
+        _watcher_register_handle(self, handle);
+
+    /* We cannot return a handle here, because handles are deduplicated via the priv->watchers_idx dictionary.
+     * The usage pattern is to use nm_netns_watcher_remove_all(), and not remove them one by one.
+     * As nm_netns_watcher_add() can return the same handle more than once, the user
+     * wouldn't know when it's safe to call nm_netns_watcher_remove_handle().
+     *
+     * This could be extended by adding a ref-count to the handles. But that is not
+     * used currently, so it's not possible to remove watcher by their handle. */
+}
+
+static void
+nm_netns_watcher_remove_handle(NMNetns *self, NMNetnsWatcherHandle *handle)
+{
+    NMNetnsPrivate *priv;
+    char            sbuf[500];
+
+    g_return_if_fail(NM_IS_NETNS(self));
+    g_return_if_fail(handle);
+    nm_assert(handle->tag);
+
+    priv = NM_NETNS_GET_PRIVATE(self);
+
+    nm_assert(g_hash_table_lookup(priv->watcher_idx, handle) == handle);
+
+    _LOGT("netns-watcher: %s %s",
+          "unregister",
+          _watcher_handle_to_string(handle, sbuf, sizeof(sbuf)));
+
+    _watcher_unregister_handle(self, handle);
+
+    if (!g_hash_table_remove(priv->watcher_idx, handle))
+        nm_assert_not_reached();
+
+    if (c_list_is_empty_or_single(&handle->watcher_tag_lst)) {
+        if (!g_hash_table_remove(priv->watcher_by_tag_idx, &handle->tag))
+            nm_assert_not_reached();
+    }
+
+    c_list_unlink_stale(&handle->watcher_tag_lst);
+    nm_g_slice_free(handle);
+
+    if (G_UNLIKELY(g_hash_table_size(priv->watcher_idx) == 0))
+        g_object_unref(self);
+}
+
+void
+nm_netns_watcher_remove_all(NMNetns *self, gconstpointer tag, gboolean all)
+{
+    NMNetnsPrivate       *priv;
+    WatcherByTag         *watcher_by_tag;
+    NMNetnsWatcherHandle *handle;
+    NMNetnsWatcherHandle *handle_safe;
+
+    g_return_if_fail(NM_IS_NETNS(self));
+
+    /* remove-all only works with handles that have a tag associated.
+     * Since NMNetns can have multiple users that are unknown to each
+     * other, it makes no sense to have a remove-all function which
+     * would remove all of them. */
+    g_return_if_fail(tag);
+
+    priv = NM_NETNS_GET_PRIVATE(self);
+
+    watcher_by_tag = g_hash_table_lookup(priv->watcher_by_tag_idx, &tag);
+    if (!watcher_by_tag)
+        return;
+
+    c_list_for_each_entry_safe (handle,
+                                handle_safe,
+                                &watcher_by_tag->watcher_by_tag_lst_head,
+                                watcher_tag_lst) {
+        gboolean is_last;
+
+        if (!all && !handle->watcher_dirty) {
+            /* Survivors are marked as dirty. This enables a pattern where you
+             * call nm_netns_watcher_add() on the elements you care about
+             * (which clears the dirty flag), and then remove all dirty ones
+             * with nm_netns_watcher_remove_all() (which marks the remaining
+             * handles as dirty for the next time). */
+            handle->watcher_dirty = TRUE;
+            continue;
+        }
+
+        is_last = c_list_is_empty_or_single(&watcher_by_tag->watcher_by_tag_lst_head);
+        nm_netns_watcher_remove_handle(self, handle);
+
+        if (is_last) {
+            /* Removing the last handle destroys the "watcher_by_tag" and may even
+             * destroy "self". We must not touch those pointers hereafter.
+             *
+             * If you ever *not* return here, make sure to handle that! */
+            return;
+        }
+    }
+}
+
+/*****************************************************************************/
+
+static void
 set_property(GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
 {
     NMNetns        *self = NM_NETNS(object);
@@ -850,6 +1421,7 @@ nm_netns_init(NMNetns *self)
     NMNetnsPrivate *priv = NM_NETNS_GET_PRIVATE(self);
 
     priv->_self_signal_user_data = self;
+
     c_list_init(&priv->l3cfg_signal_pending_lst_head);
 
     G_STATIC_ASSERT_EXPR(G_STRUCT_OFFSET(EcmpTrackObj, obj) == 0);
@@ -859,6 +1431,14 @@ nm_netns_init(NMNetns *self)
                                                        _ecmp_routes_by_ecmpid_equal,
                                                        _ecmp_routes_by_ecmpid_free,
                                                        NULL);
+
+    priv->watcher_idx = g_hash_table_new(_watcher_handle_hash, _watcher_handle_equal);
+    G_STATIC_ASSERT_EXPR(G_STRUCT_OFFSET(WatcherByTag, tag) == 0);
+    priv->watcher_by_tag_idx  = g_hash_table_new_full(nm_pdirect_hash,
+                                                     nm_pdirect_equal,
+                                                     (GDestroyNotify) _watcher_by_tag_destroy,
+                                                     NULL);
+    priv->watcher_ip_data_idx = g_hash_table_new(_watcher_ip_data_hash, _watcher_ip_data_equal);
 }
 
 static void
@@ -937,10 +1517,17 @@ dispose(GObject *object)
     nm_assert(nm_g_hash_table_size(priv->l3cfgs) == 0);
     nm_assert(c_list_is_empty(&priv->l3cfg_signal_pending_lst_head));
     nm_assert(!priv->shared_ips);
+    nm_assert(nm_g_hash_table_size(priv->watcher_idx) == 0);
+    nm_assert(nm_g_hash_table_size(priv->watcher_by_tag_idx) == 0);
+    nm_assert(nm_g_hash_table_size(priv->watcher_ip_data_idx) == 0);
 
     nm_clear_pointer(&priv->ecmp_track_by_obj, g_hash_table_destroy);
     nm_clear_pointer(&priv->ecmp_track_by_ecmpid, g_hash_table_destroy);
 
+    nm_clear_pointer(&priv->watcher_idx, g_hash_table_destroy);
+    nm_clear_pointer(&priv->watcher_by_tag_idx, g_hash_table_destroy);
+    nm_clear_pointer(&priv->watcher_ip_data_idx, g_hash_table_destroy);
+
     nm_clear_g_source_inst(&priv->signal_pending_idle_source);
 
     if (priv->platform)
diff --git a/src/core/nm-netns.h b/src/core/nm-netns.h
index 84a78f8363..7725ae79b4 100644
--- a/src/core/nm-netns.h
+++ b/src/core/nm-netns.h
@@ -59,4 +59,46 @@ void nm_netns_ip_route_ecmp_commit(NMNetns    *self,
                                    GPtrArray **routes,
                                    gboolean    is_reapply);
 
+/*****************************************************************************/
+
+typedef enum {
+    NM_NETNS_WATCHER_TYPE_IP_ADDR,
+} NMNetnsWatcherType;
+
+typedef struct {
+    union {
+        struct {
+            NMIPAddrTyped addr;
+        } ip_addr;
+    };
+} NMNetnsWatcherData;
+
+typedef struct {
+    union {
+        struct {
+            const NMPObject           *obj;
+            NMPlatformSignalChangeType change_type;
+        } ip_addr;
+    };
+} NMNetnsWatcherEventData;
+
+typedef struct _NMNetnsWatcherHandle NMNetnsWatcherHandle;
+
+typedef void (*NMNetnsWatcherCallback)(NMNetns                       *self,
+                                       NMNetnsWatcherType             watcher_type,
+                                       const NMNetnsWatcherData      *watcher_data,
+                                       gconstpointer                  tag,
+                                       const NMNetnsWatcherEventData *event_data,
+                                       gpointer                       user_data);
+
+void nm_netns_watcher_add(NMNetns                  *self,
+                          NMNetnsWatcherType        watcher_type,
+                          const NMNetnsWatcherData *watcher_data,
+                          gconstpointer             tag,
+                          NMNetnsWatcherCallback    callback,
+                          gpointer                  user_data);
+
+void
+nm_netns_watcher_remove_all(NMNetns *self, gconstpointer tag, gboolean all /* or only dirty */);
+
 #endif /* __NM_NETNS_H__ */
diff --git a/src/libnm-glib-aux/nm-inet-utils.h b/src/libnm-glib-aux/nm-inet-utils.h
index 40ba60c653..087a8af179 100644
--- a/src/libnm-glib-aux/nm-inet-utils.h
+++ b/src/libnm-glib-aux/nm-inet-utils.h
@@ -3,6 +3,8 @@
 #ifndef __NM_INET_UTILS_H__
 #define __NM_INET_UTILS_H__
 
+#include "libnm-std-aux/unaligned-fundamental.h"
+
 typedef union _NMIPAddr {
     guint8          addr_ptr[sizeof(struct in6_addr)];
     in_addr_t       addr4;
@@ -15,6 +17,11 @@ typedef union _NMIPAddr {
     NMEtherAddr _ether_addr;
 } NMIPAddr;
 
+typedef struct _NMIPAddrTyped {
+    NMIPAddr addr;
+    gint8    addr_family;
+} NMIPAddrTyped;
+
 #define NM_IP_ADDR_INIT   \
     {                     \
         .addr_ptr = { 0 } \
@@ -85,14 +92,15 @@ nm_ip_addr_set(int addr_family, gpointer dst, gconstpointer src)
 static inline gboolean
 nm_ip_addr_is_null(int addr_family, gconstpointer addr)
 {
-    NMIPAddr a;
+    struct in6_addr a6;
 
-    nm_ip_addr_set(addr_family, &a, addr);
+    nm_assert(addr);
 
     if (NM_IS_IPv4(addr_family))
-        return a.addr4 == 0;
+        return unaligned_read_ne32(addr) == 0;
 
-    return IN6_IS_ADDR_UNSPECIFIED(&a.addr6);
+    memcpy(&a6, addr, sizeof(struct in6_addr));
+    return IN6_IS_ADDR_UNSPECIFIED(&a6);
 }
 
 static inline NMIPAddr
@@ -138,6 +146,30 @@ nm_ip_addr_from_packed_array(int addr_family, gconstpointer ipaddr_arr, gsize id
 
 /*****************************************************************************/
 
+static inline int
+nm_ip_addr_typed_cmp(const NMIPAddrTyped *a, const NMIPAddrTyped *b)
+{
+    NM_CMP_SELF(a, b);
+    NM_CMP_FIELD(a, b, addr_family);
+    NM_CMP_DIRECT_MEMCMP(&a->addr, &b->addr, nm_utils_addr_family_to_size(a->addr_family));
+    return 0;
+}
+
+static inline gboolean
+nm_ip_addr_typed_equal(const NMIPAddrTyped *a, const NMIPAddrTyped *b)
+{
+    return nm_ip_addr_typed_cmp(a, b) == 0;
+}
+
+static inline void
+nm_ip_addr_typed_hash_update(NMHashState *h, const NMIPAddrTyped *addr)
+{
+    nm_hash_update_vals(h, addr->addr_family);
+    nm_hash_update_mem(h, &addr->addr, nm_utils_addr_family_to_size(addr->addr_family));
+}
+
+/*****************************************************************************/
+
 static inline guint32
 nm_ip4_addr_netmask_to_prefix(in_addr_t subnetmask)
 {
diff --git a/src/libnm-glib-aux/nm-prioq.c b/src/libnm-glib-aux/nm-prioq.c
index 3448dcd969..897d65dd51 100644
--- a/src/libnm-glib-aux/nm-prioq.c
+++ b/src/libnm-glib-aux/nm-prioq.c
@@ -21,10 +21,36 @@
 
 /*****************************************************************************/
 
-struct _NMPrioqItem {
+typedef struct _NMPrioqItem {
     void     *data;
     unsigned *idx;
-};
+} PrioqItem;
+
+/*****************************************************************************/
+
+#define _nm_assert_q(q)                                         \
+    G_STMT_START                                                \
+    {                                                           \
+        const NMPrioq *const _q2 = (q);                         \
+                                                                \
+        nm_assert(_q2);                                         \
+        nm_assert(_q2->_priv.n_items == 0 || _q2->_priv.items); \
+        nm_assert(_q2->_priv.compare_func);                     \
+    }                                                           \
+    G_STMT_END
+
+#define _nm_assert_item(q, item)                                \
+    G_STMT_START                                                \
+    {                                                           \
+        const NMPrioq *const   _q    = (q);                     \
+        const PrioqItem *const _item = (item);                  \
+                                                                \
+        _nm_assert_q(_q);                                       \
+                                                                \
+        nm_assert(_item >= _q->_priv.items);                    \
+        nm_assert(_item < &_q->_priv.items[_q->_priv.n_items]); \
+    }                                                           \
+    G_STMT_END
 
 /*****************************************************************************/
 
@@ -72,6 +98,15 @@ nm_prioq_destroy(NMPrioq *q)
     if (!q || !q->_priv.compare_func)
         return;
 
+    _nm_assert_q(q);
+
+    while (q->_priv.n_items > 0) {
+        PrioqItem *i = &q->_priv.items[--q->_priv.n_items];
+
+        if (i->idx)
+            *i->idx = NM_PRIOQ_IDX_NULL;
+    }
+
     free(q->_priv.items);
     q->_priv.compare_func = NULL;
 }
@@ -81,8 +116,7 @@ nm_prioq_destroy(NMPrioq *q)
 static int
 compare(NMPrioq *q, unsigned a, unsigned b)
 {
-    nm_assert(q);
-    nm_assert(q->_priv.compare_func);
+    _nm_assert_q(q);
     nm_assert(a != b);
     nm_assert(a < q->_priv.n_items);
     nm_assert(b < q->_priv.n_items);
@@ -99,15 +133,13 @@ compare(NMPrioq *q, unsigned a, unsigned b)
 static void
 swap(NMPrioq *q, unsigned j, unsigned k)
 {
-    nm_assert(q);
+    _nm_assert_q(q);
     nm_assert(j < q->_priv.n_items);
     nm_assert(k < q->_priv.n_items);
-
     nm_assert(!q->_priv.items[j].idx || *(q->_priv.items[j].idx) == j);
     nm_assert(!q->_priv.items[k].idx || *(q->_priv.items[k].idx) == k);
 
-    NM_SWAP(&q->_priv.items[j].data, &q->_priv.items[k].data);
-    NM_SWAP(&q->_priv.items[j].idx, &q->_priv.items[k].idx);
+    NM_SWAP(&q->_priv.items[j], &q->_priv.items[k]);
 
     if (q->_priv.items[j].idx)
         *q->_priv.items[j].idx = j;
@@ -119,7 +151,7 @@ swap(NMPrioq *q, unsigned j, unsigned k)
 static unsigned
 shuffle_up(NMPrioq *q, unsigned idx)
 {
-    nm_assert(q);
+    _nm_assert_q(q);
     nm_assert(idx < q->_priv.n_items);
 
     while (idx > 0) {
@@ -140,7 +172,7 @@ shuffle_up(NMPrioq *q, unsigned idx)
 static unsigned
 shuffle_down(NMPrioq *q, unsigned idx)
 {
-    nm_assert(q);
+    _nm_assert_q(q);
 
     for (;;) {
         unsigned j;
@@ -184,19 +216,21 @@ nm_prioq_put(NMPrioq *q, void *data, unsigned *idx)
 {
     unsigned k;
 
-    nm_assert(q);
+    _nm_assert_q(q);
+    nm_assert(q->_priv.n_items < G_MAXUINT);
 
-    if (q->_priv.n_items >= q->_priv.n_allocated) {
+    if (G_UNLIKELY(q->_priv.n_items >= q->_priv.n_allocated)) {
         q->_priv.n_allocated = NM_MAX((q->_priv.n_items + 1u) * 2u, 16u);
-        q->_priv.items       = g_renew(struct _NMPrioqItem, q->_priv.items, q->_priv.n_allocated);
+        q->_priv.items       = g_renew(PrioqItem, q->_priv.items, q->_priv.n_allocated);
     }
 
     k = q->_priv.n_items++;
 
-    q->_priv.items[k] = (struct _NMPrioqItem){
+    q->_priv.items[k] = (PrioqItem){
         .data = data,
         .idx  = idx,
     };
+
     if (idx)
         *idx = k;
 
@@ -204,71 +238,88 @@ nm_prioq_put(NMPrioq *q, void *data, unsigned *idx)
 }
 
 static void
-remove_item(NMPrioq *q, struct _NMPrioqItem *i)
+remove_item(NMPrioq *q, PrioqItem *i)
 {
-    struct _NMPrioqItem *l;
-    unsigned             k;
+    PrioqItem *l;
+    unsigned   k;
 
-    nm_assert(q);
-    nm_assert(i);
-    nm_assert(q->_priv.n_items > 0);
-    nm_assert(i >= q->_priv.items);
-    nm_assert(i < &q->_priv.items[q->_priv.n_items]);
+    _nm_assert_item(q, i);
+
+    if (i->idx)
+        *i->idx = NM_PRIOQ_IDX_NULL;
+
+    q->_priv.n_items--;
 
-    l = &q->_priv.items[q->_priv.n_items - 1u];
+    l = &q->_priv.items[q->_priv.n_items];
 
     if (i == l) {
-        /* Last entry, let's just remove it */
-        q->_priv.n_items--;
+        /* Last entry, nothing to do. */
         return;
     }
 
-    /* Not last entry, let's replace the last entry with
-     * this one, and reshuffle */
+    /* Not last entry, let's replace this entry with the last one, and
+     * reshuffle */
+
     k = i - q->_priv.items;
 
     *i = *l;
+
     if (i->idx)
         *i->idx = k;
-    q->_priv.n_items--;
 
     k = shuffle_down(q, k);
     shuffle_up(q, k);
 }
 
-_nm_pure static struct _NMPrioqItem *
+static PrioqItem *
 find_item(NMPrioq *q, void *data, unsigned *idx)
 {
-    struct _NMPrioqItem *i;
-
-    nm_assert(q);
+    PrioqItem *i;
 
-    if (q->_priv.n_items <= 0)
-        return NULL;
+    _nm_assert_q(q);
 
-    if (idx) {
-        if (*idx == NM_PRIOQ_IDX_NULL || *idx >= q->_priv.n_items)
-            return NULL;
-
-        i = &q->_priv.items[*idx];
-        if (i->data == data)
-            return i;
-    } else {
+    if (G_UNLIKELY(!idx)) {
+        /* We allow using NMPrioq without "idx". In that case, it does a linear
+         * search for the data. */
         for (i = q->_priv.items; i < &q->_priv.items[q->_priv.n_items]; i++) {
             if (i->data == data)
                 return i;
         }
+        return NULL;
     }
 
-    return NULL;
+    /* If the user however provides an "idx" pointer, then we assert that it is
+     * consistent. That is, if data is not in the queue, then we require that
+     * "*idx" is NM_PRIOQ_IDX_NULL, and otherwise we require that we really
+     * find "data" at index "*idx".
+     *
+     * This means, when the user calls nm_prioq_{remove,update,reshuffle}()
+     * with an "idx", then they must make sure that the index is consistent.
+     * Usually this means they are required to initialize the index to
+     * NM_PRIOQ_IDX_NULL while the data is not in the heap.
+     *
+     * This is done to assert more, and requires a stricter usage of the API
+     * (in the hope to find misuses of the index). */
+
+    if (*idx >= q->_priv.n_items) {
+        nm_assert(*idx == NM_PRIOQ_IDX_NULL);
+        return NULL;
+    }
+
+    i = &q->_priv.items[*idx];
+
+    if (i->data != data)
+        return nm_assert_unreachable_val(NULL);
+
+    return i;
 }
 
 gboolean
 nm_prioq_remove(NMPrioq *q, void *data, unsigned *idx)
 {
-    struct _NMPrioqItem *i;
+    PrioqItem *i;
 
-    nm_assert(q);
+    _nm_assert_q(q);
 
     i = find_item(q, data, idx);
     if (!i)
@@ -278,28 +329,60 @@ nm_prioq_remove(NMPrioq *q, void *data, unsigned *idx)
     return TRUE;
 }
 
+static void
+reshuffle_item(NMPrioq *q, PrioqItem *i)
+{
+    unsigned k;
+
+    _nm_assert_item(q, i);
+
+    k = i - q->_priv.items;
+    k = shuffle_down(q, k);
+    shuffle_up(q, k);
+}
+
 gboolean
 nm_prioq_reshuffle(NMPrioq *q, void *data, unsigned *idx)
 {
-    struct _NMPrioqItem *i;
-    unsigned             k;
+    PrioqItem *i;
 
-    nm_assert(q);
+    _nm_assert_q(q);
 
     i = find_item(q, data, idx);
     if (!i)
         return FALSE;
 
-    k = i - q->_priv.items;
-    k = shuffle_down(q, k);
-    shuffle_up(q, k);
+    reshuffle_item(q, i);
     return TRUE;
 }
 
+void
+nm_prioq_update(NMPrioq *q, void *data, unsigned *idx, bool queued /* or else remove */)
+{
+    PrioqItem *i;
+
+    _nm_assert_q(q);
+
+    i = find_item(q, data, idx);
+
+    if (!i) {
+        if (queued)
+            nm_prioq_put(q, data, idx);
+        return;
+    }
+
+    if (!queued) {
+        remove_item(q, i);
+        return;
+    }
+
+    reshuffle_item(q, i);
+}
+
 void *
 nm_prioq_peek_by_index(NMPrioq *q, unsigned idx)
 {
-    nm_assert(q);
+    _nm_assert_q(q);
 
     if (idx >= q->_priv.n_items)
         return NULL;
@@ -312,7 +395,7 @@ nm_prioq_pop(NMPrioq *q)
 {
     void *data;
 
-    nm_assert(q);
+    _nm_assert_q(q);
 
     if (q->_priv.n_items <= 0)
         return NULL;
diff --git a/src/libnm-glib-aux/nm-prioq.h b/src/libnm-glib-aux/nm-prioq.h
index 918c644724..51e5b059fb 100644
--- a/src/libnm-glib-aux/nm-prioq.h
+++ b/src/libnm-glib-aux/nm-prioq.h
@@ -43,6 +43,8 @@ void     nm_prioq_put(NMPrioq *q, void *data, unsigned *idx);
 gboolean nm_prioq_remove(NMPrioq *q, void *data, unsigned *idx);
 gboolean nm_prioq_reshuffle(NMPrioq *q, void *data, unsigned *idx);
 
+void nm_prioq_update(NMPrioq *q, void *data, unsigned *idx, bool queued /* or else remove */);
+
 void *nm_prioq_peek_by_index(NMPrioq *q, unsigned idx) _nm_pure;
 
 static inline void *
@@ -53,7 +55,7 @@ nm_prioq_peek(NMPrioq *q)
 
 void *nm_prioq_pop(NMPrioq *q);
 
-#define NM_PRIOQ_FOREACH_ITEM(q, p) for (unsigned _i = 0; (p = nm_prioq_peek_by_index(q, _i)); _i++)
+#define nm_prioq_for_each(q, p) for (unsigned _i = 0; (p = nm_prioq_peek_by_index((q), _i)); _i++)
 
 _nm_pure static inline unsigned
 nm_prioq_size(NMPrioq *q)
diff --git a/src/libnm-glib-aux/nm-shared-utils.c b/src/libnm-glib-aux/nm-shared-utils.c
index c71d3dc190..8b255101b3 100644
--- a/src/libnm-glib-aux/nm-shared-utils.c
+++ b/src/libnm-glib-aux/nm-shared-utils.c
@@ -20,6 +20,7 @@
 
 #include "c-list/src/c-list.h"
 #include "nm-errno.h"
+#include "nm-time-utils.h"
 #include "nm-str-buf.h"
 #include "nm-time-utils.h"
 
@@ -4840,6 +4841,50 @@ nm_g_child_watch_source_new(GPid            pid,
     return source;
 }
 
+gboolean
+nm_g_timeout_reschedule(GSource   **src,
+                        gint64     *p_expiry_msec,
+                        gint64      expiry_msec,
+                        GSourceFunc func,
+                        gpointer    user_data)
+{
+    gint64 now_msec;
+    gint64 timeout_msec;
+
+    /* (Re-)Schedules a timeout at "expiry_msec" (in
+     * nm_utils_get_monotonic_timestamp_msec() scale).
+     *
+     * If a source is already scheduled in "*src" and "*p_expiry_msec" is
+     * identical to "expiry_msec", then we assume the timer is already ticking,
+     * and nothing is rescheduled.
+     *
+     * Otherwise, "*src" gets cancelled (if any), a new timer is scheduled
+     * (assigned to "*src") and the new expiry is written to "*p_expiry_msec".
+     */
+
+    nm_assert(src);
+    nm_assert(p_expiry_msec);
+
+    if (*src) {
+        if (*p_expiry_msec == expiry_msec) {
+            /* already scheduled with same expiry. */
+            return FALSE;
+        }
+        nm_clear_g_source_inst(src);
+    }
+
+    now_msec = nm_utils_get_monotonic_timestamp_msec();
+
+    if (expiry_msec <= now_msec)
+        timeout_msec = 0;
+    else
+        timeout_msec = NM_MIN(expiry_msec - now_msec, (gint64) G_MAXUINT);
+
+    *p_expiry_msec = expiry_msec;
+    *src           = nm_g_timeout_add_source(timeout_msec, func, user_data);
+    return TRUE;
+}
+
 /*****************************************************************************/
 
 #define _CTX_LOG(fmt, ...)                                                                       \
diff --git a/src/libnm-glib-aux/nm-shared-utils.h b/src/libnm-glib-aux/nm-shared-utils.h
index 05d96cbd7e..d9f1d7b008 100644
--- a/src/libnm-glib-aux/nm-shared-utils.h
+++ b/src/libnm-glib-aux/nm-shared-utils.h
@@ -1543,6 +1543,12 @@ nm_g_timeout_add_source(guint timeout_msec, GSourceFunc func, gpointer user_data
         NULL);
 }
 
+gboolean nm_g_timeout_reschedule(GSource   **src,
+                                 gint64     *p_expiry_msec,
+                                 gint64      expiry_msec,
+                                 GSourceFunc func,
+                                 gpointer    user_data);
+
 static inline GSource *
 nm_g_timeout_add_seconds_source(guint timeout_sec, GSourceFunc func, gpointer user_data)
 {
diff --git a/src/libnm-glib-aux/tests/test-shared-general.c b/src/libnm-glib-aux/tests/test-shared-general.c
index 3eaca5474a..563c370243 100644
--- a/src/libnm-glib-aux/tests/test-shared-general.c
+++ b/src/libnm-glib-aux/tests/test-shared-general.c
@@ -2348,7 +2348,7 @@ test_garray(void)
 static int
 _prioq_cmp(gconstpointer a, gconstpointer b)
 {
-    NM_CMP_DIRECT(GPOINTER_TO_UINT(a), GPOINTER_TO_UINT(b));
+    NM_CMP_DIRECT(*((const guint32 *) a), *((const guint32 *) b));
     return 0;
 }
 
@@ -2362,11 +2362,12 @@ static void
 test_nm_prioq(void)
 {
     nm_auto_prioq NMPrioq q = NM_PRIOQ_ZERO;
-    gpointer              data[200];
-    gpointer              data_pop[200];
+    guint32               data[200];
+    const guint32        *data_pop[200];
     guint                 data_idx[G_N_ELEMENTS(data)];
     guint                 i;
     guint                 n;
+    guint                 m;
     gpointer              p;
 
     if (nmtst_get_rand_one_case_in(10))
@@ -2379,37 +2380,67 @@ test_nm_prioq(void)
 
     g_assert(nm_prioq_size(&q) == 0);
 
-    if (nmtst_get_rand_one_case_in(10))
+    if (nmtst_get_rand_one_case_in(100))
         return;
 
     for (i = 0; i < G_N_ELEMENTS(data); i++) {
-        data[i]     = GUINT_TO_POINTER((nmtst_get_rand_uint32() % G_N_ELEMENTS(data)) + 1u);
+        data[i]     = nmtst_get_rand_uint32() % G_N_ELEMENTS(data);
         data_idx[i] = NM_PRIOQ_IDX_NULL;
     }
 
-    nm_prioq_put(&q, data[0], NULL);
+    nm_prioq_put(&q, &data[0], NULL);
     g_assert(nm_prioq_size(&q) == 1);
 
     p = nm_prioq_pop(&q);
-    g_assert(p == data[0]);
+    g_assert(p == &data[0]);
     g_assert(nm_prioq_size(&q) == 0);
 
     g_assert(!nm_prioq_pop(&q));
 
     n = nmtst_get_rand_uint32() % G_N_ELEMENTS(data);
     for (i = 0; i < n; i++)
-        nm_prioq_put(&q, data[i], &data_idx[i]);
+        nm_prioq_put(&q, &data[i], &data_idx[i]);
 
-    g_assert_cmpint(nm_prioq_size(&q), ==, n);
+    m = n;
+    for (i = 0; i < n; i++) {
+        if (!nmtst_get_rand_bool())
+            continue;
 
-    if (nmtst_get_rand_one_case_in(10))
+        data[i] = nmtst_get_rand_uint32() % G_N_ELEMENTS(data);
+        switch (nmtst_get_rand_uint32() % 4) {
+        case 0:
+            nm_prioq_reshuffle(&q, &data[i], &data_idx[i]);
+            break;
+        case 1:
+            nm_prioq_remove(&q, &data[i], nmtst_get_rand_bool() ? &data_idx[i] : NULL);
+            m--;
+            break;
+        case 2:
+            nm_prioq_update(&q, &data[i], &data_idx[i], TRUE);
+            break;
+        case 3:
+            nm_prioq_update(&q, &data[i], nmtst_get_rand_bool() ? &data_idx[i] : NULL, FALSE);
+            m--;
+            break;
+        }
+    }
+
+    g_assert_cmpint(nm_prioq_size(&q), ==, m);
+
+    if (nmtst_get_rand_one_case_in(50))
         return;
 
-    for (i = 0; i < n; i++) {
+    for (i = 0; i < m; i++) {
         data_pop[i] = nm_prioq_pop(&q);
         g_assert(data_pop[i]);
-        if (i > 0)
+        g_assert_cmpint(*data_pop[i], >=, 0);
+        g_assert_cmpint(*data_pop[i], <, G_N_ELEMENTS(data));
+        g_assert(data_pop[i] >= &data[0]);
+        g_assert(data_pop[i] < &data[n]);
+        if (i > 0) {
             g_assert(_prioq_cmp(data_pop[i - 1], data_pop[i]) <= 0);
+            g_assert_cmpint(*data_pop[i - 1], <=, *data_pop[i]);
+        }
     }
 
     g_assert(!nm_prioq_pop(&q));
diff --git a/src/libnm-lldp/nm-lldp-neighbor.c b/src/libnm-lldp/nm-lldp-neighbor.c
index f1e2d42eb0..a2a9695e85 100644
--- a/src/libnm-lldp/nm-lldp-neighbor.c
+++ b/src/libnm-lldp/nm-lldp-neighbor.c
@@ -735,6 +735,7 @@ nm_lldp_neighbor_new(size_t raw_size)
 
     n->raw_size  = raw_size;
     n->ref_count = 1;
+    n->prioq_idx = NM_PRIOQ_IDX_NULL;
     return n;
 }
 
diff --git a/src/libnm-platform/nm-linux-platform.c b/src/libnm-platform/nm-linux-platform.c
index c75fb3bf81..b6c2902d20 100644
--- a/src/libnm-platform/nm-linux-platform.c
+++ b/src/libnm-platform/nm-linux-platform.c
@@ -8149,6 +8149,7 @@ do_add_addrroute(NMPlatform      *platform,
             do_request_one_type_by_needle_object(platform, obj_id);
     }
 
+    NM_SET_OUT(out_extack_msg, g_steal_pointer(&extack_msg));
     return wait_for_nl_response_to_nmerr(seq_result);
 }
 
diff --git a/src/libnm-platform/nm-platform.c b/src/libnm-platform/nm-platform.c
index eddbaba376..deaf72acab 100644
--- a/src/libnm-platform/nm-platform.c
+++ b/src/libnm-platform/nm-platform.c
@@ -4593,53 +4593,6 @@ nm_platform_ip_address_flush(NMPlatform *self, int addr_family, int ifindex)
 
 /*****************************************************************************/
 
-static gboolean
-_route_is_temporary_not_available(NMPlatform      *self,
-                                  int              err,
-                                  const NMPObject *obj,
-                                  const char     **out_err_reason)
-{
-    const NMPlatformIPXRoute   *rx;
-    const NMPlatformIP6Address *a;
-
-    nm_assert(NM_IS_PLATFORM(self));
-    nm_assert(NMP_OBJECT_IS_VALID(obj));
-
-    if (err != -EINVAL)
-        return FALSE;
-
-    rx = NMP_OBJECT_CAST_IPX_ROUTE(obj);
-
-    if (rx->rx.rt_source != NM_IP_CONFIG_SOURCE_USER) {
-        /* we only allow this workaround for routes added manually by the user. */
-        return FALSE;
-    }
-
-    if (NMP_OBJECT_GET_TYPE(obj) == NMP_OBJECT_TYPE_IP4_ROUTE) {
-        return FALSE;
-    } else {
-        const NMPlatformIP6Route *r = &rx->r6;
-
-        /* trying to add an IPv6 route with pref-src fails, if the address is
-         * still tentative (rh#1452684). We need to hack around that.
-         *
-         * Detect it, by guessing whether that's the case. */
-
-        if (IN6_IS_ADDR_UNSPECIFIED(&r->pref_src))
-            return FALSE;
-
-        a = nm_platform_ip6_address_get(self, r->ifindex, &r->pref_src);
-        if (!a)
-            return FALSE;
-        if (!NM_FLAGS_HAS(a->n_ifa_flags, IFA_F_TENTATIVE)
-            || NM_FLAGS_HAS(a->n_ifa_flags, IFA_F_DADFAILED))
-            return FALSE;
-
-        *out_err_reason = "tentative IPv6 src address not ready";
-        return TRUE;
-    }
-}
-
 static guint
 _ipv6_temporary_addr_prefixes_keep_hash(gconstpointer ptr)
 {
@@ -4968,8 +4921,8 @@ nm_platform_ip_route_get_prune_list(NMPlatform            *self,
  *   at the end of the operation. Note that if @routes contains
  *   the same route, then it will not be deleted. @routes overrules
  *   @routes_prune list.
- * @out_temporary_not_available: (allow-none) (out): routes that could
- *   currently not be synced. The caller shall keep them and try later again.
+ * @out_routes_failed: (allow-none) (out): routes that could
+ *   not be synced/added.
  *
  * Returns: %TRUE on success.
  */
@@ -4979,7 +4932,7 @@ nm_platform_ip_route_sync(NMPlatform *self,
                           int         ifindex,
                           GPtrArray  *routes,
                           GPtrArray  *routes_prune,
-                          GPtrArray **out_temporary_not_available)
+                          GPtrArray **out_routes_failed)
 {
     const int                      IS_IPv4 = NM_IS_IPv4(addr_family);
     const NMPlatformVTableRoute   *vt;
@@ -4999,9 +4952,7 @@ nm_platform_ip_route_sync(NMPlatform *self,
 
     for (i_type = 0; routes && i_type < 2; i_type++) {
         for (i = 0; i < routes->len; i++) {
-            gs_free char *extack_msg          = NULL;
-            gboolean      gateway_route_added = FALSE;
-            int           r2;
+            gs_free char *extack_msg = NULL;
             int           r;
 
             conf_o = routes->pdata[i];
@@ -5058,147 +5009,59 @@ nm_platform_ip_route_sync(NMPlatform *self,
                 }
             }
 
-sync_route_add:
             r = nm_platform_ip_route_add(self,
                                          NMP_NLM_FLAG_APPEND
                                              | NMP_NLM_FLAG_SUPPRESS_NETLINK_FAILURE,
                                          conf_o,
                                          &extack_msg);
-            if (r < 0) {
-                const char *err_reason = NULL;
-
-                if (r == -EEXIST) {
-                    /* Don't fail for EEXIST. It's not clear that the existing route
-                     * is identical to the one that we were about to add. However,
-                     * above we should have deleted conflicting (non-identical) routes. */
-                    if (_LOGD_ENABLED()) {
-                        plat_entry =
-                            nm_platform_lookup_entry(self, NMP_CACHE_ID_TYPE_OBJECT_TYPE, conf_o);
-                        if (!plat_entry) {
-                            _LOG3D("route-sync: adding route %s failed with EEXIST, however we "
-                                   "cannot find such a route",
-                                   nmp_object_to_string(conf_o,
-                                                        NMP_OBJECT_TO_STRING_PUBLIC,
-                                                        sbuf1,
-                                                        sizeof(sbuf1)));
-                        } else if (vt->route_cmp(NMP_OBJECT_CAST_IPX_ROUTE(conf_o),
-                                                 NMP_OBJECT_CAST_IPX_ROUTE(plat_entry->obj),
-                                                 NM_PLATFORM_IP_ROUTE_CMP_TYPE_SEMANTICALLY)
-                                   != 0) {
-                            _LOG3D("route-sync: adding route %s failed due to existing "
-                                   "(different!) route %s",
-                                   nmp_object_to_string(conf_o,
-                                                        NMP_OBJECT_TO_STRING_PUBLIC,
-                                                        sbuf1,
-                                                        sizeof(sbuf1)),
-                                   nmp_object_to_string(plat_entry->obj,
-                                                        NMP_OBJECT_TO_STRING_PUBLIC,
-                                                        sbuf2,
-                                                        sizeof(sbuf2)));
-                        }
-                    }
-                } else if (NMP_OBJECT_CAST_IP_ROUTE(conf_o)->rt_source < NM_IP_CONFIG_SOURCE_USER) {
-                    _LOG3D("route-sync: ignore failure to add IPv%c route: %s: %s",
-                           vt->is_ip4 ? '4' : '6',
-                           nmp_object_to_string(conf_o,
-                                                NMP_OBJECT_TO_STRING_PUBLIC,
-                                                sbuf1,
-                                                sizeof(sbuf1)),
-                           nm_strerror(r));
-                } else if (out_temporary_not_available
-                           && _route_is_temporary_not_available(self, r, conf_o, &err_reason)) {
-                    _LOG3D("route-sync: ignore temporary failure to add route (%s, %s): %s",
-                           nm_strerror(r),
-                           err_reason,
-                           nmp_object_to_string(conf_o,
-                                                NMP_OBJECT_TO_STRING_PUBLIC,
-                                                sbuf1,
-                                                sizeof(sbuf1)));
-                    if (!*out_temporary_not_available)
-                        *out_temporary_not_available =
-                            g_ptr_array_new_full(0, (GDestroyNotify) nmp_object_unref);
-                    g_ptr_array_add(*out_temporary_not_available,
-                                    (gpointer) nmp_object_ref(conf_o));
-                } else if (!gateway_route_added
-                           && ((r == -ENETUNREACH && vt->is_ip4
-                                && !!NMP_OBJECT_CAST_IP4_ROUTE(conf_o)->gateway)
-                               || (r == -EHOSTUNREACH && !vt->is_ip4
-                                   && !IN6_IS_ADDR_UNSPECIFIED(
-                                       &NMP_OBJECT_CAST_IP6_ROUTE(conf_o)->gateway)))) {
-                    NMPObject oo;
-
-                    if (vt->is_ip4) {
-                        const NMPlatformIP4Route *rt = NMP_OBJECT_CAST_IP4_ROUTE(conf_o);
-
-                        nmp_object_stackinit(
-                            &oo,
-                            NMP_OBJECT_TYPE_IP4_ROUTE,
-                            &((NMPlatformIP4Route){
-                                .ifindex       = rt->ifindex,
-                                .network       = rt->gateway,
-                                .plen          = 32,
-                                .metric        = nm_platform_ip4_route_get_effective_metric(rt),
-                                .rt_source     = rt->rt_source,
-                                .table_coerced = nm_platform_ip_route_get_effective_table(
-                                    NM_PLATFORM_IP_ROUTE_CAST(rt)),
-                            }));
-                    } else {
-                        const NMPlatformIP6Route *rt = NMP_OBJECT_CAST_IP6_ROUTE(conf_o);
-
-                        nmp_object_stackinit(
-                            &oo,
-                            NMP_OBJECT_TYPE_IP6_ROUTE,
-                            &((NMPlatformIP6Route){
-                                .ifindex       = rt->ifindex,
-                                .network       = rt->gateway,
-                                .plen          = 128,
-                                .metric        = nm_platform_ip6_route_get_effective_metric(rt),
-                                .rt_source     = rt->rt_source,
-                                .table_coerced = nm_platform_ip_route_get_effective_table(
-                                    NM_PLATFORM_IP_ROUTE_CAST(rt)),
-                            }));
-                    }
-
-                    _LOG3D("route-sync: failure to add IPv%c route: %s: %s; try adding direct "
-                           "route to gateway %s",
-                           vt->is_ip4 ? '4' : '6',
-                           nmp_object_to_string(conf_o,
-                                                NMP_OBJECT_TO_STRING_PUBLIC,
-                                                sbuf1,
-                                                sizeof(sbuf1)),
-                           nm_strerror(r),
-                           nmp_object_to_string(&oo,
-                                                NMP_OBJECT_TO_STRING_PUBLIC,
-                                                sbuf2,
-                                                sizeof(sbuf2)));
-
-                    r2 = nm_platform_ip_route_add(self,
-                                                  NMP_NLM_FLAG_APPEND
-                                                      | NMP_NLM_FLAG_SUPPRESS_NETLINK_FAILURE,
-                                                  &oo,
-                                                  NULL);
-
-                    if (r2 < 0) {
-                        _LOG3D("route-sync: failure to add gateway IPv%c route: %s: %s",
-                               vt->is_ip4 ? '4' : '6',
+            if (r == 0) {
+                /* success */
+            } else if (r == -EEXIST) {
+                /* Don't fail for EEXIST. It's not clear that the existing route
+                 * is identical to the one that we were about to add. However,
+                 * above we should have deleted conflicting (non-identical) routes. */
+                if (_LOGD_ENABLED()) {
+                    plat_entry =
+                        nm_platform_lookup_entry(self, NMP_CACHE_ID_TYPE_OBJECT_TYPE, conf_o);
+                    if (!plat_entry) {
+                        _LOG3D("route-sync: adding route %s failed with EEXIST, however we "
+                               "cannot find such a route",
+                               nmp_object_to_string(conf_o,
+                                                    NMP_OBJECT_TO_STRING_PUBLIC,
+                                                    sbuf1,
+                                                    sizeof(sbuf1)));
+                    } else if (vt->route_cmp(NMP_OBJECT_CAST_IPX_ROUTE(conf_o),
+                                             NMP_OBJECT_CAST_IPX_ROUTE(plat_entry->obj),
+                                             NM_PLATFORM_IP_ROUTE_CMP_TYPE_SEMANTICALLY)
+                               != 0) {
+                        _LOG3D("route-sync: adding route %s failed due to existing "
+                               "(different!) route %s",
                                nmp_object_to_string(conf_o,
                                                     NMP_OBJECT_TO_STRING_PUBLIC,
                                                     sbuf1,
                                                     sizeof(sbuf1)),
-                               nm_strerror(r2));
+                               nmp_object_to_string(plat_entry->obj,
+                                                    NMP_OBJECT_TO_STRING_PUBLIC,
+                                                    sbuf2,
+                                                    sizeof(sbuf2)));
                     }
+                }
+            } else {
+                _LOG3D(
+                    "route-sync: failure to add IPv%c route: %s: %s%s%s%s",
+                    vt->is_ip4 ? '4' : '6',
+                    nmp_object_to_string(conf_o, NMP_OBJECT_TO_STRING_PUBLIC, sbuf1, sizeof(sbuf1)),
+                    nm_strerror(r),
+                    NM_PRINT_FMT_QUOTED(extack_msg, " (", extack_msg, ")", ""));
 
-                    gateway_route_added = TRUE;
-                    goto sync_route_add;
-                } else {
-                    _LOG3W("route-sync: failure to add IPv%c route: %s: %s",
-                           vt->is_ip4 ? '4' : '6',
-                           nmp_object_to_string(conf_o,
-                                                NMP_OBJECT_TO_STRING_PUBLIC,
-                                                sbuf1,
-                                                sizeof(sbuf1)),
-                           nm_strerror(r));
-                    success = FALSE;
+                success = FALSE;
+
+                if (out_routes_failed) {
+                    if (!*out_routes_failed) {
+                        *out_routes_failed =
+                            g_ptr_array_new_with_free_func((GDestroyNotify) nmp_object_unref);
+                    }
+                    g_ptr_array_add(*out_routes_failed, (gpointer) nmp_object_ref(conf_o));
                 }
             }
         }
@@ -5346,7 +5209,7 @@ _ip_route_add(NMPlatform *self, NMPNlmFlags flags, NMPObject *obj_stack, char **
     char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     int  ifindex;
 
-    _CHECK_SELF(self, klass, FALSE);
+    _CHECK_SELF(self, klass, -NME_BUG);
 
     /* The caller already ensures that this is a stack allocated copy, that
      * - stays alive for the duration of the call.
@@ -7037,7 +6900,6 @@ nm_platform_ip4_route_to_string_full(const NMPlatformIP4Route     *route,
         "%s"         /* rto_min */
         "%s"         /* quickack */
         "%s"         /* mtu */
-        "%s"         /* r_force_commit */
         "",
         nm_net_aux_rtnl_rtntype_n2a_maybe_buf(nm_platform_route_type_uncoerce(route->type_coerced),
                                               str_type),
@@ -7104,8 +6966,7 @@ nm_platform_ip4_route_to_string_full(const NMPlatformIP4Route     *route,
                                                        " mtu %s%" G_GUINT32_FORMAT,
                                                        route->lock_mtu ? "lock " : "",
                                                        route->mtu)
-                                      : "",
-        route->r_force_commit ? " force-commit" : "");
+                                      : "");
 
     if ((n_nexthops == 1 && route->ifindex > 0) || n_nexthops == 0) {
         /* A plain single hop route. Nothing extra to remark. */
@@ -7225,7 +7086,6 @@ nm_platform_ip6_route_to_string(const NMPlatformIP6Route *route, char *buf, gsiz
         "%s"         /* quickack */
         "%s"         /* mtu */
         "%s"         /* pref */
-        "%s"         /* r_force_commit */
         "",
         nm_net_aux_rtnl_rtntype_n2a_maybe_buf(nm_platform_route_type_uncoerce(route->type_coerced),
                                               str_type),
@@ -7292,8 +7152,7 @@ nm_platform_ip6_route_to_string(const NMPlatformIP6Route *route, char *buf, gsiz
             str_pref,
             " pref %s",
             nm_icmpv6_router_pref_to_string(route->rt_pref, str_pref2, sizeof(str_pref2)))
-                       : "",
-        route->r_force_commit ? " force-commit" : "");
+                       : "");
 
     return buf;
 }
@@ -8680,8 +8539,7 @@ nm_platform_ip4_route_hash_update(const NMPlatformIP4Route *obj,
                                                   obj->lock_initcwnd,
                                                   obj->lock_initrwnd,
                                                   obj->lock_mtu,
-                                                  obj->lock_mss,
-                                                  obj->r_force_commit));
+                                                  obj->lock_mss));
         break;
     }
 }
@@ -8824,8 +8682,6 @@ nm_platform_ip4_route_cmp(const NMPlatformIP4Route *a,
         NM_CMP_FIELD(a, b, initrwnd);
         NM_CMP_FIELD(a, b, mtu);
         NM_CMP_FIELD(a, b, rto_min);
-        if (cmp_type == NM_PLATFORM_IP_ROUTE_CMP_TYPE_FULL)
-            NM_CMP_FIELD_UNSAFE(a, b, r_force_commit);
         break;
     }
     return 0;
@@ -8925,8 +8781,7 @@ nm_platform_ip6_route_hash_update(const NMPlatformIP6Route *obj,
                                                   obj->lock_initcwnd,
                                                   obj->lock_initrwnd,
                                                   obj->lock_mtu,
-                                                  obj->lock_mss,
-                                                  obj->r_force_commit),
+                                                  obj->lock_mss),
                             obj->window,
                             obj->cwnd,
                             obj->initcwnd,
@@ -9016,8 +8871,6 @@ nm_platform_ip6_route_cmp(const NMPlatformIP6Route *a,
             NM_CMP_DIRECT(_route_pref_normalize(a->rt_pref), _route_pref_normalize(b->rt_pref));
         else
             NM_CMP_FIELD(a, b, rt_pref);
-        if (cmp_type == NM_PLATFORM_IP_ROUTE_CMP_TYPE_FULL)
-            NM_CMP_FIELD_UNSAFE(a, b, r_force_commit);
         break;
     }
     return 0;
@@ -9339,7 +9192,6 @@ nm_platform_ip4_address_generate_device_route(const NMPlatformIP4Address *addr,
                                               int                         ifindex,
                                               guint32                     route_table,
                                               guint32                     route_metric,
-                                              gboolean                    force_commit,
                                               NMPlatformIP4Route         *dst)
 {
     in_addr_t network_4;
@@ -9369,15 +9221,14 @@ nm_platform_ip4_address_generate_device_route(const NMPlatformIP4Address *addr,
     }
 
     *dst = (NMPlatformIP4Route){
-        .ifindex        = ifindex,
-        .rt_source      = NM_IP_CONFIG_SOURCE_KERNEL,
-        .network        = network_4,
-        .plen           = addr->plen,
-        .pref_src       = addr->address,
-        .table_coerced  = nm_platform_route_table_coerce(route_table),
-        .metric         = route_metric,
-        .scope_inv      = nm_platform_route_scope_inv(NM_RT_SCOPE_LINK),
-        .r_force_commit = force_commit,
+        .ifindex       = ifindex,
+        .rt_source     = NM_IP_CONFIG_SOURCE_KERNEL,
+        .network       = network_4,
+        .plen          = addr->plen,
+        .pref_src      = addr->address,
+        .table_coerced = nm_platform_route_table_coerce(route_table),
+        .metric        = route_metric,
+        .scope_inv     = nm_platform_route_scope_inv(NM_RT_SCOPE_LINK),
     };
 
     nm_platform_ip_route_normalize(AF_INET, (NMPlatformIPRoute *) dst);
diff --git a/src/libnm-platform/nm-platform.h b/src/libnm-platform/nm-platform.h
index 08a7716e39..86e01d63de 100644
--- a/src/libnm-platform/nm-platform.h
+++ b/src/libnm-platform/nm-platform.h
@@ -243,13 +243,6 @@ typedef enum {
 
 guint _nm_platform_signal_id_get(NMPlatformSignalIdType signal_type);
 
-typedef enum {
-    NM_PLATFORM_SIGNAL_NONE,
-    NM_PLATFORM_SIGNAL_ADDED,
-    NM_PLATFORM_SIGNAL_CHANGED,
-    NM_PLATFORM_SIGNAL_REMOVED,
-} NMPlatformSignalChangeType;
-
 /* Default value for adding an IPv4 route. This is also what iproute2 does.
  * Note that contrary to IPv6, you can add routes with metric 0 and it is even
  * the default.
@@ -2306,6 +2299,19 @@ nm_platform_ip_route_get_gateway(int addr_family, const NMPlatformIPRoute *route
     return &((NMPlatformIP6Route *) route)->gateway;
 }
 
+static inline gconstpointer
+nm_platform_ip_route_get_pref_src(int addr_family, const NMPlatformIPRoute *route)
+{
+    nm_assert_addr_family(addr_family);
+
+    if (!route)
+        return NULL;
+
+    if (NM_IS_IPv4(addr_family))
+        return &((NMPlatformIP4Route *) route)->pref_src;
+    return &((NMPlatformIP6Route *) route)->pref_src;
+}
+
 int nm_platform_ip_route_add(NMPlatform      *self,
                              NMPNlmFlags      flags,
                              const NMPObject *route,
@@ -2326,7 +2332,7 @@ gboolean nm_platform_ip_route_sync(NMPlatform *self,
                                    int         ifindex,
                                    GPtrArray  *routes,
                                    GPtrArray  *routes_prune,
-                                   GPtrArray **out_temporary_not_available);
+                                   GPtrArray **out_routes_failed);
 
 gboolean nm_platform_ip_route_flush(NMPlatform *self, int addr_family, int ifindex);
 
diff --git a/src/libnm-platform/nmp-base.h b/src/libnm-platform/nmp-base.h
index 80d254b261..4802b03553 100644
--- a/src/libnm-platform/nmp-base.h
+++ b/src/libnm-platform/nmp-base.h
@@ -28,6 +28,15 @@
 /*****************************************************************************/
 
 typedef enum {
+    NM_PLATFORM_SIGNAL_NONE,
+    NM_PLATFORM_SIGNAL_ADDED,
+    NM_PLATFORM_SIGNAL_CHANGED,
+    NM_PLATFORM_SIGNAL_REMOVED,
+} NMPlatformSignalChangeType;
+
+/*****************************************************************************/
+
+typedef enum {
     NM_PLATFORM_LINK_DUPLEX_UNKNOWN,
     NM_PLATFORM_LINK_DUPLEX_HALF,
     NM_PLATFORM_LINK_DUPLEX_FULL,
diff --git a/src/libnm-platform/nmp-object.h b/src/libnm-platform/nmp-object.h
index 0d5f84b310..408f0318cb 100644
--- a/src/libnm-platform/nmp-object.h
+++ b/src/libnm-platform/nmp-object.h
@@ -1183,21 +1183,6 @@ nm_platform_lookup_object_by_addr_family(NMPlatform   *platform,
 
 /*****************************************************************************/
 
-static inline gboolean
-nmp_object_get_force_commit(const NMPObject *obj)
-{
-    switch (NMP_OBJECT_GET_TYPE(obj)) {
-    case NMP_OBJECT_TYPE_IP4_ADDRESS:
-    case NMP_OBJECT_TYPE_IP6_ADDRESS:
-        return NMP_OBJECT_CAST_IP_ADDRESS(obj)->a_force_commit;
-    case NMP_OBJECT_TYPE_IP4_ROUTE:
-    case NMP_OBJECT_TYPE_IP6_ROUTE:
-        return NMP_OBJECT_CAST_IP_ROUTE(obj)->r_force_commit;
-    default:
-        return nm_assert_unreachable_val(FALSE);
-    }
-}
-
 static inline const char *
 nmp_object_link_get_ifname(const NMPObject *obj)
 {
diff --git a/src/libnm-platform/nmp-plobj.h b/src/libnm-platform/nmp-plobj.h
index e149150d29..833167f678 100644
--- a/src/libnm-platform/nmp-plobj.h
+++ b/src/libnm-platform/nmp-plobj.h
@@ -255,7 +255,6 @@ NMPlatformIP4Route *nm_platform_ip4_address_generate_device_route(const NMPlatfo
                                                                   int                 ifindex,
                                                                   guint32             route_table,
                                                                   guint32             route_metric,
-                                                                  gboolean            force_commit,
                                                                   NMPlatformIP4Route *dst);
 
 typedef enum {