rib: fix traversal with /32 route

[ upstream commit 1b984e9 ]

If a /32 route is entered in the RIB the code to traverse
will not see end of the tree. This is due to trying
to do a negative shift which is an undefined in C.

Fix by checking for max depth as is already done in rib6.

Fixes: 5a5793a ("rib: add RIB library")

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>

lib/rib/rte_rib.c

@@ -73,6 +73,8 @@ is_covered(uint32_t ip1, uint32_t ip2, uint8_t depth)
 static inline struct rte_rib_node *
 get_nxt_node(struct rte_rib_node *node, uint32_t ip)
 {
+	if (node->depth == RIB_MAXDEPTH)
+		return NULL;
 	return (ip & (1 << (31 - node->depth))) ? node->right : node->left;
 }