From e092341df3e6420e4aac2cda37f4936226f5d00c Mon Sep 17 00:00:00 2001
From: "Ondrej Zajicek (work)" <santiago@crfreenet.org>
Date: Fri, 10 May 2019 14:51:33 +0200
Subject: [PATCH] Nest: Handle unresolvable routes as invalid

Handle unresolvable routes (recursive routes that cannot be resolved) as
invalid, i.e. deprioritize tham and do not allow them for propagation.
Such route now shows as 'unresolvable' instead of 'unreachable'.
---
 nest/route.h    | 10 ++++++++--
 nest/rt-attr.c  |  1 +
 nest/rt-show.c  |  5 ++++-
 nest/rt-table.c |  2 +-
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/nest/route.h b/nest/route.h
index c7c44ecc..2256b671 100644
--- a/nest/route.h
+++ b/nest/route.h
@@ -270,8 +270,10 @@ typedef struct rte {
 #define REF_STALE	4		/* Route is stale in a refresh cycle */
 #define REF_DISCARD	8		/* Route is scheduled for discard */
 
+static inline int rte_is_resolvable(rte *r);
+
 /* Route is valid for propagation (may depend on other flags in the future), accepts NULL */
-static inline int rte_is_valid(rte *r) { return r && !(r->flags & REF_FILTERED); }
+static inline int rte_is_valid(rte *r) { return r && !(r->flags & REF_FILTERED) && rte_is_resolvable(r); }
 
 /* Route just has REF_FILTERED flag */
 static inline int rte_is_filtered(rte *r) { return !!(r->flags & REF_FILTERED); }
@@ -451,7 +453,8 @@ typedef struct rta {
 #define RTD_BLACKHOLE 2			/* Silently drop packets */
 #define RTD_UNREACHABLE 3		/* Reject as unreachable */
 #define RTD_PROHIBIT 4			/* Administratively prohibited */
-#define RTD_MAX 5
+#define RTD_UNRESOLVABLE 5		/* Recursive route is unresolvable */
+#define RTD_MAX 6
 
 					/* Flags for net->n.flags, used by kernel syncer */
 #define KRF_INSTALLED 0x80		/* This route should be installed in the kernel */
@@ -472,6 +475,9 @@ static inline const char *rta_dest_name(uint n)
 static inline int rte_is_reachable(rte *r)
 { return r->attrs->dest == RTD_UNICAST; }
 
+static inline int rte_is_resolvable(rte *r)
+{ return r->attrs->dest != RTD_UNRESOLVABLE; }
+
 
 /*
  *	Extended Route Attributes
diff --git a/nest/rt-attr.c b/nest/rt-attr.c
index d0d11617..3cbd25b0 100644
--- a/nest/rt-attr.c
+++ b/nest/rt-attr.c
@@ -64,6 +64,7 @@ const char * rta_dest_names[RTD_MAX] = {
   [RTD_BLACKHOLE]	= "blackhole",
   [RTD_UNREACHABLE]	= "unreachable",
   [RTD_PROHIBIT]	= "prohibited",
+  [RTD_UNRESOLVABLE]	= "unresolvable",
 };
 
 pool *rta_pool;
diff --git a/nest/rt-show.c b/nest/rt-show.c
index 1f1b73d2..f3706d78 100644
--- a/nest/rt-show.c
+++ b/nest/rt-show.c
@@ -34,7 +34,7 @@ rt_show_rte(struct cli *c, byte *ia, rte *e, struct rt_show_data *d, ea_list *tm
   byte from[IPA_MAX_TEXT_LENGTH+8];
   byte tm[TM_DATETIME_BUFFER_SIZE], info[256];
   rta *a = e->attrs;
-  int primary = (e->net->routes == e);
+  int primary = (e->net->routes == e) && rte_is_valid(e);
   int sync_error = (e->net->n.flags & KRF_SYNC_ERROR);
   void (*get_route_info)(struct rte *, byte *buf, struct ea_list *attrs);
   struct nexthop *nh;
@@ -139,6 +139,9 @@ rt_show_net(struct cli *c, net *n, struct rt_show_data *d)
 	}
       else if (d->export_mode)
 	{
+	  if (!rte_is_valid(e))
+	    goto skip;
+
 	  struct proto *ep = ec->proto;
 	  int ic = ep->import_control ? ep->import_control(ep, &e, &tmpa, c->show_pool) : 0;
 
diff --git a/nest/rt-table.c b/nest/rt-table.c
index efc1f1d7..03d63154 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -2609,7 +2609,7 @@ rt_update_hostentry(rtable *tab, struct hostentry *he)
 
   /* Reset the hostentry */
   he->src = NULL;
-  he->dest = RTD_UNREACHABLE;
+  he->dest = RTD_UNRESOLVABLE;
   he->nexthop_linkable = 0;
   he->igp_metric = 0;