From 6d87cf4be7536433d263609828414e687e1d4f08 Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Fri, 1 Oct 2021 14:11:13 +0200
Subject: [PATCH] Kernel routes are flushed on shutdown by kernel scan, not by
 table scan

---
 sysdep/unix/krt.c | 31 ++++++++++++++-----------------
 sysdep/unix/krt.h |  1 +
 2 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/sysdep/unix/krt.c b/sysdep/unix/krt.c
index b98e7ec0..32bfe7fc 100644
--- a/sysdep/unix/krt.c
+++ b/sysdep/unix/krt.c
@@ -542,23 +542,6 @@ krt_is_installed(struct krt_proto *p, net *n)
   return n->routes && bmap_test(&p->p.main_channel->export_map, n->routes->rte.id);
 }
 
-static void
-krt_flush_routes(struct krt_proto *p)
-{
-  struct rtable *t = p->p.main_channel->table;
-
-  KRT_TRACE(p, D_EVENTS, "Flushing kernel routes");
-  FIB_WALK(&t->fib, net, n)
-    {
-      if (krt_is_installed(p, n))
-	{
-	  /* FIXME: this does not work if gw is changed in export filter */
-	  krt_replace_rte(p, n->n.addr, NULL, &n->routes->rte);
-	}
-    }
-  FIB_WALK_END;
-}
-
 static struct rte *
 krt_export_net(struct krt_proto *p, net *net)
 {
@@ -637,6 +620,9 @@ krt_got_route(struct krt_proto *p, rte *e, s8 src)
 #endif
   /* The rest is for KRT_SRC_BIRD (or KRT_SRC_UNKNOWN) */
 
+  /* Deleting all routes if flush is requested */
+  if (p->flush_routes)
+    goto delete;
 
   /* We wait for the initial feed to have correct installed state */
   if (!p->ready)
@@ -729,6 +715,17 @@ krt_prune(struct krt_proto *p)
     p->initialized = 1;
 }
 
+static void
+krt_flush_routes(struct krt_proto *p)
+{
+  KRT_TRACE(p, D_EVENTS, "Flushing kernel routes");
+  p->flush_routes = 1;
+  krt_init_scan(p);
+  krt_do_scan(p);
+  /* No prune! */
+  p->flush_routes = 0;
+}
+
 void
 krt_got_route_async(struct krt_proto *p, rte *e, int new, s8 src)
 {
diff --git a/sysdep/unix/krt.h b/sysdep/unix/krt.h
index cd4bd07d..f6ad6fde 100644
--- a/sysdep/unix/krt.h
+++ b/sysdep/unix/krt.h
@@ -66,6 +66,7 @@ struct krt_proto {
   byte ready;			/* Initial feed has been finished */
   byte initialized;		/* First scan has been finished */
   byte reload;			/* Next scan is doing reload */
+  byte flush_routes;		/* Scanning to flush */
 };
 
 extern pool *krt_pool;