nat: avoid division by zero

Return error instead of dividing by zero.

Type: fix
Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: I9f6a942e87ab87e8f1921e744ec1add45884e74a

diff --git a/src/plugins/nat/nat_det.c b/src/plugins/nat/nat_det.c
index cad0d2a..65a669b 100644 (file)
--- a/src/plugins/nat/nat_det.c
+++ b/src/plugins/nat/nat_det.c
@@ -82,13 +82,20 @@ snat_det_add_map (snat_main_t * sm, ip4_address_t * in_addr, u8 in_plen,
          num_sessions = num_sessions * 1000 - 1;
        }
 
+      u32 sharing_ratio = (1 << (32 - in_plen)) / (1 << (32 - out_plen));
+      if (!sharing_ratio)
+       {
+         // avoid division by zero
+         return VNET_API_ERROR_INVALID_VALUE;
+       }
+
       pool_get (sm->det_maps, det_map);
       clib_memset (det_map, 0, sizeof (*det_map));
       det_map->in_addr.as_u32 = in_cmp.as_u32;
       det_map->in_plen = in_plen;
       det_map->out_addr.as_u32 = out_cmp.as_u32;
       det_map->out_plen = out_plen;
-      det_map->sharing_ratio = (1 << (32 - in_plen)) / (1 << (32 - out_plen));
+      det_map->sharing_ratio = sharing_ratio;
       det_map->ports_per_host = (65535 - 1023) / det_map->sharing_ratio;
 
       vec_validate_init_empty (det_map->sessions, num_sessions,