evaluate: throw distinct error if map exists but contains no objects

nft would throw misleading error in case map exists but doesn't contain
expected objects.

nft add rule filter in ct helper set tcp dport map @foo
Error: Expression is not a map
add rule filter in ct helper set tcp dport map @foo
                                               ^^^^
nft list table filter
table ip filter {
        map foo {
                type inet_service : ifname
        }
...

clarify this.

Reported-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/src/evaluate.c b/src/evaluate.c
index 195508236e1e6a2a5b458f431f03ac11497443da..c8010852eecb2f349f739e0465e31c9e47d9fef5 100644 (file)
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -2806,10 +2806,12 @@ static int stmt_evaluate_objref_map(struct eval_ctx *ctx, struct stmt *stmt)
        case EXPR_SYMBOL:
                if (expr_evaluate(ctx, &map->mappings) < 0)
                        return -1;
-               if (map->mappings->ops->type != EXPR_SET_REF ||
-                   !(map->mappings->set->flags & NFT_SET_OBJECT))
+               if (map->mappings->ops->type != EXPR_SET_REF)
                        return expr_error(ctx->msgs, map->mappings,
                                          "Expression is not a map");
+               if (!(map->mappings->set->flags & NFT_SET_OBJECT))
+                       return expr_error(ctx->msgs, map->mappings,
+                                         "Expression is not a map with objects");
                break;
        default:
                BUG("invalid mapping expression %s\n",