nft_dup_ipv4
struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
.size = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv4)),