[PATCH nft 4/7] evaluate: simplify sets as set elems evaluation

[Pablo Neira Ayuso <pablo@netfilter.org>]

After normalizing set element representation for EXPR_MAPPING, it is
possible to simplify:

  a6b75b837f5e ("evaluate: set: Allow for set elems to be sets")

Extend tests/shell coverage to exercise merging nested sets.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/evaluate.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/src/evaluate.c b/src/evaluate.c
index 0b7508a18ede..85c446a124ee 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -2090,27 +2090,17 @@ static int expr_evaluate_set(struct eval_ctx *ctx, struct expr **expr)
 			return expr_error(ctx->msgs, i,
 					  "Set reference cannot be part of another set");
 
-		if (elem->etype == EXPR_SET_ELEM &&
-		    elem->key->etype == EXPR_SET) {
-			struct expr *new = expr_get(elem->key);
-
-			expr_set(set)->set_flags |= expr_set(elem->key)->set_flags;
-			list_replace(&i->list, &new->list);
-			expr_free(i);
-			i = new;
-			elem = i;
-		}
-
 		if (!expr_is_constant(i))
 			return expr_error(ctx->msgs, i,
 					  "Set member is not constant");
 
-		if (i->etype == EXPR_SET) {
+		if (i->etype == EXPR_SET_ELEM &&
+		    i->key->etype == EXPR_SET) {
 			/* Merge recursive set definitions */
-			list_splice_tail_init(&expr_set(i)->expressions, &i->list);
+			list_splice_tail_init(&expr_set(i->key)->expressions, &i->list);
 			list_del(&i->list);
-			expr_set(set)->size      += expr_set(i)->size - 1;
-			expr_set(set)->set_flags |= expr_set(i)->set_flags;
+			expr_set(set)->size      += expr_set(i->key)->size - 1;
+			expr_set(set)->set_flags |= expr_set(i->key)->set_flags;
 			expr_free(i);
 		} else if (!expr_is_singleton(i)) {
 			expr_set(set)->set_flags |= NFT_SET_INTERVAL;
-- 
2.30.2