From 17fab002a1c0c946d035802665a77e2983f534a7 Mon Sep 17 00:00:00 2001
From: Igor Putovny <igor.putovny@nic.cz>
Date: Thu, 16 May 2024 13:50:08 +0200
Subject: [PATCH] Backport settle timer from v3

---
 conf/confbase.Y |  3 +++
 lib/birdlib.h   |  3 +++
 lib/settle.h    | 64 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 lib/settle.h

diff --git a/conf/confbase.Y b/conf/confbase.Y
index 1d5738ff0..e81ac2843 100644
--- a/conf/confbase.Y
+++ b/conf/confbase.Y
@@ -22,6 +22,7 @@ CF_HDR
 #include "nest/bfd.h"
 #include "nest/cli.h"
 #include "filter/filter.h"
+#include "lib/settle.h"
 
 /* FIXME: Turn on YYERROR_VERBOSE and work around lots of bison bugs? */
 
@@ -92,6 +93,7 @@ CF_DECLS
   struct proto_spec ps;
   struct channel_limit cl;
   struct timeformat *tf;
+  struct settle_config settle;
   mpls_label_stack *mls;
   struct bytestring *bs;
 }
@@ -110,6 +112,7 @@ CF_DECLS
 
 %type <i> expr bool pxlen4
 %type <time> expr_us time
+%type <settle> settle
 %type <a> ipa
 %type <net> net_ip4_ net_ip4 net_ip6_ net_ip6 net_ip_ net_ip net_or_ipa
 %type <net_ptr> net_ net_any net_vpn4_ net_vpn6_ net_vpn_ net_roa4_ net_roa6_ net_roa_ net_ip6_sadr_ net_mpls_
diff --git a/lib/birdlib.h b/lib/birdlib.h
index 81d4908ac..c1090417a 100644
--- a/lib/birdlib.h
+++ b/lib/birdlib.h
@@ -13,6 +13,9 @@
 
 /* Ugly structure offset handling macros */
 
+#define SAME_TYPE(a, b)	({ int _ = ((a) != (b)); !_; })
+#define TYPE_CAST(from, to, what) ( SAME_TYPE(((from) NULL), (what)), ((to) (what)))
+
 struct align_probe { char x; long int y; };
 
 #define OFFSETOF(s, i) ((size_t) &((s *)0)->i)
diff --git a/lib/settle.h b/lib/settle.h
new file mode 100644
index 000000000..4c92c3cca
--- /dev/null
+++ b/lib/settle.h
@@ -0,0 +1,64 @@
+/*
+ *	BIRD -- Settle timer
+ *
+ *	(c) 2022 Maria Matejka <mq@jmq.cz>
+ *	(c) 2022 CZ.NIC z.s.p.o.
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_SETTLE_H_
+#define _BIRD_SETTLE_H_
+
+#include "lib/birdlib.h"
+#include "lib/timer.h"
+
+struct settle_config {
+  btime min, max;
+};
+
+struct settle {
+  union {
+    /* Timer hook polymorphism. */
+    struct {
+      resource _r;
+      void (*hook)(struct settle *);
+    };
+    timer tm;
+  };
+  struct settle_config cf;
+  btime started;
+};
+
+STATIC_ASSERT(OFFSETOF(struct settle, hook) == OFFSETOF(struct settle, tm) + OFFSETOF(timer, hook));
+
+#define SETTLE_INIT(_cfp, _hook, _data) (struct settle) { .tm = { .data = (_data), .hook = TYPE_CAST(void (*)(struct settle *), void (*)(struct timer *), (_hook)), }, .cf = ({ASSERT_DIE((_cfp)->min <= (_cfp)->max); *(_cfp); }), }
+
+
+static inline void settle_init(struct settle *s, struct settle_config *cf, void (*hook)(struct settle *), void *data)
+{
+  *s = SETTLE_INIT(cf, hook, data);
+}
+
+#define settle_active(s) tm_active(&(s)->tm)
+
+static inline void settle_kick(struct settle *s)
+{
+  if (!tm_active(&s->tm))
+  {
+    s->started = current_time();
+    tm_set(&s->tm, s->started + s->cf.min);
+  }
+  else
+  {
+    btime now = current_time();
+    tm_set(&s->tm, MIN_(now + s->cf.min, s->started + s->cf.max));
+  }
+}
+
+static inline void settle_cancel(struct settle *s)
+{
+  tm_stop(&s->tm);
+}
+
+#endif
-- 
2.47.2