fib: do not dump no-longer valid adjacencies

In some cases, we can refer to no-longer adjacencies (eg. in traces). Do
not dump them in this case as they are probably incorrect (memory can be
reused).

Type: fix

Change-Id: Ib653ba066bb6595ec6ec37d313a3124bce0eeed3
Signed-off-by: Benoît Ganne <bganne@cisco.com>
(cherry picked from commit 138c37af5291e2045075052a4db036be03be4a85)

3 files changed, 17 insertions, 2 deletions

diff --git a/src/vnet/adj/adj.c b/src/vnet/adj/adj.c
index bafa33618cb..0966d97cc6d 100644
--- a/src/vnet/adj/adj.c
+++ b/src/vnet/adj/adj.c
@@ -139,6 +139,10 @@ format_ip_adjacency (u8 * s, va_list * args)
 
     adj_index = va_arg (*args, u32);
     fiaf = va_arg (*args, format_ip_adjacency_flags_t);
+
+    if (!adj_is_valid(adj_index))
+      return format(s, "<invalid adjacency>");
+
     adj = adj_get(adj_index);
 
     switch (adj->lookup_next_index)
diff --git a/src/vnet/adj/adj.h b/src/vnet/adj/adj.h
index fb3dc368db0..4c38b041b61 100644
--- a/src/vnet/adj/adj.h
+++ b/src/vnet/adj/adj.h
@@ -432,7 +432,13 @@ extern int adj_per_adj_counters;
 static inline ip_adjacency_t *
 adj_get (adj_index_t adj_index)
 {
-    return (vec_elt_at_index(adj_pool, adj_index));
+    return (pool_elt_at_index(adj_pool, adj_index));
+}
+
+static inline int
+adj_is_valid(adj_index_t adj_index)
+{
+  return !(pool_is_free_index(adj_pool, adj_index));
 }
 
 /**
diff --git a/src/vnet/adj/adj_mcast.c b/src/vnet/adj/adj_mcast.c
index 4454afec630..c94d28e8713 100644
--- a/src/vnet/adj/adj_mcast.c
+++ b/src/vnet/adj/adj_mcast.c
@@ -329,7 +329,12 @@ format_adj_mcast (u8* s, va_list *ap)
 {
     index_t index = va_arg(*ap, index_t);
     CLIB_UNUSED(u32 indent) = va_arg(*ap, u32);
-    ip_adjacency_t * adj = adj_get(index);
+    ip_adjacency_t * adj;
+
+    if (!adj_is_valid(index))
+      return format(s, "<invalid adjacency>");
+
+    adj = adj_get(index);
 
     s = format(s, "%U-mcast: ",
                format_fib_protocol, adj->ia_nh_proto);