optimize: merging concatenation is unsupported

Existing concatenation cannot be merge at this stage, skip them
otherwise this assertion is hit:

 nft: optimize.c:434: rule_build_stmt_matrix_stmts: Assertion `k >= 0' failed

Extend existing test to cover this.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/optimize.c b/src/optimize.c
index 2340ef46..419a37f2 100644
--- a/src/optimize.c
+++ b/src/optimize.c
@@ -352,6 +352,10 @@ static int rule_collect_stmts(struct optimize_ctx *ctx, struct rule *rule)
 				clone->ops = &unsupported_stmt_ops;
 				break;
 			}
+			if (stmt->expr->left->etype == EXPR_CONCAT) {
+				clone->ops = &unsupported_stmt_ops;
+				break;
+			}
 		case STMT_VERDICT:
 			clone->expr = expr_get(stmt->expr);
 			break;