Limit containment

1 files changed, 49 insertions, 0 deletions

diff --git a/nest/limit.h b/nest/limit.h
new file mode 100644
index 00000000..5838ad3b
--- /dev/null
+++ b/nest/limit.h
@@ -0,0 +1,49 @@
+/*
+ *	BIRD Internet Routing Daemon -- Limits
+ *
+ *	(c) 1998--2000 Martin Mares <mj@ucw.cz>
+ *	(c) 2021 Maria Matejka <mq@jmq.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_LIMIT_H_
+#define _BIRD_LIMIT_H_
+
+struct limit {
+  u32 max;
+  u32 count;
+  int (*action)(struct limit *, void *data);
+};
+
+static inline int limit_do_action(struct limit *l, void *data)
+{
+  return l->action ? l->action(l, data) : 1;
+}
+
+static inline int limit_push(struct limit *l, void *data)
+{
+  if ((l->count >= l->max) && limit_do_action(l, data))
+    return 1;
+
+  l->count++;
+  return 0;
+}
+
+static inline void limit_pop(struct limit *l)
+{
+  --l->count;
+}
+
+static inline void limit_reset(struct limit *l)
+{
+  l->count = 0;
+}
+
+static inline void limit_update(struct limit *l, void *data, u32 max)
+{
+  if (l->count > (l->max = max))
+    limit_do_action(l, data);
+}
+
+#endif