l3cfg: emit signal when NML3ConfigData changes

src/core/nm-l3cfg.c

@@ -302,6 +302,7 @@ static NM_UTILS_ENUM2STR_DEFINE(
     NML3ConfigNotifyType,
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_ACD_EVENT, "acd-event"),
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_IPV4LL_EVENT, "ipv4ll-event"),
+    NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_L3CD_CHANGED, "l3cd-changed"),
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_PLATFORM_CHANGE, "platform-change"),
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_PLATFORM_CHANGE_ON_IDLE, "platform-change-on-idle"),
     NM_UTILS_ENUM2STR(NM_L3_CONFIG_NOTIFY_TYPE_POST_COMMIT, "post-commit"),
@@ -348,6 +349,7 @@ _l3_config_notify_data_to_string(const NML3ConfigNotifyData *notify_data,
 {
     char      sbuf_addr[NM_UTILS_INET_ADDRSTRLEN];
     char      sbuf100[100];
+    char      sbufobf[NM_HASH_OBFUSCATE_PTR_STR_BUF_SIZE];
     char *    s = sbuf;
     gsize     l = sbuf_size;
     in_addr_t addr4;
@@ -359,6 +361,19 @@ _l3_config_notify_data_to_string(const NML3ConfigNotifyData *notify_data,
     nm_utils_strbuf_seek_end(&s, &l);
 
     switch (notify_data->notify_type) {
+    case NM_L3_CONFIG_NOTIFY_TYPE_L3CD_CHANGED:
+        nm_utils_strbuf_append(
+            &s,
+            &l,
+            ", l3cd-old=%s",
+            NM_HASH_OBFUSCATE_PTR_STR(notify_data->l3cd_changed.l3cd_old, sbufobf));
+        nm_utils_strbuf_append(
+            &s,
+            &l,
+            ", l3cd-new=%s",
+            NM_HASH_OBFUSCATE_PTR_STR(notify_data->l3cd_changed.l3cd_new, sbufobf));
+        nm_utils_strbuf_append(&s, &l, ", commited=%d", notify_data->l3cd_changed.commited);
+        break;
     case NM_L3_CONFIG_NOTIFY_TYPE_ACD_EVENT:
         nm_utils_strbuf_append(&s,
                                &l,
@@ -424,6 +439,23 @@ _nm_l3cfg_emit_signal_notify_simple(NML3Cfg *self, NML3ConfigNotifyType notify_t
     _nm_l3cfg_emit_signal_notify(self, &notify_data);
 }
 
+static void
+_nm_l3cfg_emit_signal_notify_l3cd_changed(NML3Cfg *             self,
+                                          const NML3ConfigData *l3cd_old,
+                                          const NML3ConfigData *l3cd_new,
+                                          gboolean              commited)
+{
+    NML3ConfigNotifyData notify_data;
+
+    notify_data.notify_type  = NM_L3_CONFIG_NOTIFY_TYPE_L3CD_CHANGED;
+    notify_data.l3cd_changed = (typeof(notify_data.l3cd_changed)){
+        .l3cd_old = l3cd_old,
+        .l3cd_new = l3cd_new,
+        .commited = commited,
+    };
+    _nm_l3cfg_emit_signal_notify(self, &notify_data);
+}
+
 /*****************************************************************************/
 
 static void
@@ -3009,6 +3041,12 @@ _l3cfg_update_combined_config(NML3Cfg *              self,
     l3cd_old                           = g_steal_pointer(&self->priv.p->combined_l3cd_merged);
     self->priv.p->combined_l3cd_merged = nm_l3_config_data_seal(g_steal_pointer(&l3cd));
     merged_changed                     = TRUE;
+
+    _nm_l3cfg_emit_signal_notify_l3cd_changed(self,
+                                              l3cd_old,
+                                              self->priv.p->combined_l3cd_merged,
+                                              FALSE);
+
     if (!to_commit) {
         NM_SET_OUT(out_old, g_steal_pointer(&l3cd_old));
         NM_SET_OUT(out_changed_combined_l3cd, TRUE);
@@ -3020,6 +3058,12 @@ out:
         self->priv.p->combined_l3cd_commited =
             nm_l3_config_data_ref(self->priv.p->combined_l3cd_merged);
         commited_changed = TRUE;
+
+        _nm_l3cfg_emit_signal_notify_l3cd_changed(self,
+                                                  l3cd_commited_old,
+                                                  self->priv.p->combined_l3cd_commited,
+                                                  TRUE);
+
         NM_SET_OUT(out_old, g_steal_pointer(&l3cd_commited_old));
         NM_SET_OUT(out_changed_combined_l3cd, TRUE);
     }

src/core/nm-l3cfg.h

@@ -88,6 +88,12 @@ nm_l3_acd_addr_info_find_track_info(const NML3AcdAddrInfo *addr_info,
 }
 
 typedef enum {
+    /* emitted when the merged/commited NML3ConfigData instance changes.
+     * Note that this gets emitted "under unsafe circumstances". That means,
+     * you should not perform complex operations inside this callback,
+     * 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,
@@ -117,6 +123,12 @@ struct _NML3IPv4LL;
 typedef struct {
     NML3ConfigNotifyType notify_type;
     union {
+        struct {
+            const NML3ConfigData *l3cd_old;
+            const NML3ConfigData *l3cd_new;
+            bool                  commited;
+        } l3cd_changed;
+
         struct {
             NML3AcdAddrInfo info;
         } acd_event;

src/core/tests/test-l3cfg.c

@@ -187,6 +187,12 @@ _test_l3cfg_signal_notify(NML3Cfg *                   l3cfg,
             nm_assert(NM_IS_L3_CONFIG_DATA(ti->l3cd));
             nm_assert(ti->tag);
         }
+    } else if (notify_data->notify_type == NM_L3_CONFIG_NOTIFY_TYPE_L3CD_CHANGED) {
+        g_assert(!notify_data->l3cd_changed.l3cd_old
+                 || NM_IS_L3_CONFIG_DATA(notify_data->l3cd_changed.l3cd_old));
+        g_assert(!notify_data->l3cd_changed.l3cd_new
+                 || NM_IS_L3_CONFIG_DATA(notify_data->l3cd_changed.l3cd_new));
+        return;
     }
 
     switch (tdata->notify_type) {