Refactor Merkle sync into bounded bidirectional rounds with atomic member updates

src/chat/chat_sync.c

@@ -602,6 +602,10 @@ static void cs_on_conn_down(struct ETCP_CONN* conn, int event, void* arg) { (voi
 static void cs_on_conn_status(struct ETCP_CONN* conn, int status, void* arg) {
     switch (status) {
     case ETCP_CONN_STATUS_UP:   cs_on_conn_up(conn, ETCP_CBK_EVENT_UP, arg); break;
+    case ETCP_CONN_STATUS_REINIT:
+        cs_on_conn_down(conn, ETCP_CBK_EVENT_DOWN, arg);
+        cs_on_conn_up(conn, ETCP_CBK_EVENT_UP, arg);
+        break;
     case ETCP_CONN_STATUS_DOWN:
     case ETCP_CONN_STATUS_DELETE: cs_on_conn_down(conn, ETCP_CBK_EVENT_DOWN, arg); break;
     default: break;
@@ -683,6 +687,11 @@ int chat_sync_init(struct UTUN_INSTANCE* inst) {
     cs->initialized = 1;
     inst->chat_sync = cs;
 
+    if (member_sync_init(inst) < 0) {
+        DEBUG_ERROR(DEBUG_CATEGORY_MEMBER_SYNC, "%s: member synchronization initialization failed", CS_ID);
+        inst->chat_sync = NULL; u_free(cs); return -1;
+    }
+
     etcp_bind(inst, ETCP_RT_ID_CHAT_SYNC, chat_sync_recv_cb);
     etcp_add_conn_status_cbk(inst, cs_on_conn_status, cs);
 
@@ -693,7 +702,6 @@ int chat_sync_init(struct UTUN_INSTANCE* inst) {
     cs->info_req_timer = NULL;
     cs->join_timer = NULL;
 
-    member_sync_init(inst);
     member_sync_add_apply_cbk(inst, cs_on_member_applied, cs);
     utun_add_peer_sleep_cbk(inst, cs_on_peer_sleep, cs);
     chat_admin_init(inst);