src: allow anon set concatenation with ether and vlan

vlan id uses integer type (which has a length of 0).

Using it was possible, but listing would assert:
python: mergesort.c:24: concat_expr_msort_value: Assertion `ilen > 0' failed.

There are two reasons for this.
First reason is that the udata/typeof information lacks the 'vlan id'
part, because internally this is 'payload . binop(payload AND mask)'.

binop lacks an udata store.  It makes little sense to store it,
'typeof' keyword expects normal match syntax.

So, when storing udata, store the left hand side of the binary
operation, i.e. the load of the 2-byte key.

With that resolved, delinerization could work, but concat_elem_expr()
would splice 12 bits off the elements value, but it should be 16 (on
a byte boundary).

Signed-off-by: Florian Westphal <fw@strlen.de>

2 files changed, 22 insertions, 5 deletions

diff --git a/src/expression.c b/src/expression.c
index deb649e1..7390089c 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -879,17 +879,30 @@ static void concat_expr_print(const struct expr *expr, struct output_ctx *octx)
 #define NFTNL_UDATA_SET_KEY_CONCAT_SUB_DATA 1
 #define NFTNL_UDATA_SET_KEY_CONCAT_SUB_MAX  2
 
+static struct expr *expr_build_udata_recurse(struct expr *e)
+{
+	switch (e->etype) {
+	case EXPR_BINOP:
+		return e->left;
+	default:
+		break;
+	}
+
+	return e;
+}
+
 static int concat_expr_build_udata(struct nftnl_udata_buf *udbuf,
 				    const struct expr *concat_expr)
 {
 	struct nftnl_udata *nest;
+	struct expr *expr, *tmp;
 	unsigned int i = 0;
-	struct expr *expr;
 
-	list_for_each_entry(expr, &concat_expr->expressions, list) {
+	list_for_each_entry_safe(expr, tmp, &concat_expr->expressions, list) {
 		struct nftnl_udata *nest_expr;
 		int err;
 
+		expr = expr_build_udata_recurse(expr);
 		if (!expr_ops(expr)->build_udata || i >= NFT_REG32_SIZE)
 			return -1;
 
diff --git a/src/netlink.c b/src/netlink.c
index 89d864ed..799cf9b8 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -1114,17 +1114,21 @@ static struct expr *concat_elem_expr(struct expr *key,
 				     struct expr *data, int *off)
 {
 	const struct datatype *subtype;
+	unsigned int sub_length;
 	struct expr *expr;
 
 	if (key) {
 		(*off)--;
-		expr = constant_expr_splice(data, key->len);
+		sub_length = round_up(key->len, BITS_PER_BYTE);
+
+		expr = constant_expr_splice(data, sub_length);
 		expr->dtype = datatype_get(key->dtype);
 		expr->byteorder = key->byteorder;
 		expr->len = key->len;
 	} else {
 		subtype = concat_subtype_lookup(dtype->type, --(*off));
-		expr = constant_expr_splice(data, subtype->size);
+		sub_length = round_up(subtype->size, BITS_PER_BYTE);
+		expr = constant_expr_splice(data, sub_length);
 		expr->dtype = subtype;
 		expr->byteorder = subtype->byteorder;
 	}
@@ -1136,7 +1140,7 @@ static struct expr *concat_elem_expr(struct expr *key,
 	    expr->dtype->basetype->type == TYPE_BITMASK)
 		expr = bitmask_expr_to_binops(expr);
 
-	data->len -= netlink_padding_len(expr->len);
+	data->len -= netlink_padding_len(sub_length);
 
 	return expr;
 }