lib/route: allow rtnl_neigh_get_ext_flags to fail

Make rtnl_neigh_get_ext_flags return -NLE_NOATTR when the flags are not present (so the user can know when the kernel didn't send those flags). The absence of the attribute does not however imply that the kernel lacks support for the ext flags.
thom311 · Sep 13, 2024 · d9332d6 · d9332d6
1 parent c238ca1
commit d9332d6
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/include/netlink/route/neighbour.h b/include/netlink/route/neighbour.h
@@ -62,7 +62,8 @@ extern void rtnl_neigh_set_ext_flags(struct rtnl_neigh *,
  uint32_t);
 extern void rtnl_neigh_unset_ext_flags(struct rtnl_neigh *,
  uint32_t);
-extern uint32_t rtnl_neigh_get_ext_flags(struct rtnl_neigh *);
+extern int rtnl_neigh_get_ext_flags(struct rtnl_neigh *,
+ uint32_t *);
 
 extern void rtnl_neigh_set_ifindex(struct rtnl_neigh *,
  int);

diff --git a/lib/route/neigh.c b/lib/route/neigh.c
@@ -1037,9 +1037,13 @@ void rtnl_neigh_set_ext_flags(struct rtnl_neigh *neigh, uint32_t ext_flags)
  neigh->ce_mask |= NEIGH_ATTR_EXT_FLAGS;
 }
 
-uint32_t rtnl_neigh_get_ext_flags(struct rtnl_neigh *neigh)
+int rtnl_neigh_get_ext_flags(struct rtnl_neigh *neigh, uint32_t *out_val)
 {
- return neigh->n_ext_flags;
+ if (!(neigh->ce_mask & NEIGH_ATTR_EXT_FLAGS))
+ return -NLE_NOATTR;
+
+ *out_val = neigh->n_ext_flags;
+ return NLE_SUCCESS;
 }
 
 void rtnl_neigh_unset_ext_flags(struct rtnl_neigh *neigh, uint32_t ext_flags)