[PATCH nft v2 1/8] netlink_delinearize: allow postprocessing on concatenated elements

[Florian Westphal <fw@strlen.de>]

Currently there is no case where the individual expressions inside a
mapped concatenation need to be munged.

However, to support proper delinearization for an input like
'rule netdev nt nc set update ether saddr . vlan id timeout 5s @macset'

we need to allow this.

Right now, this gets listed as:

update @macset { @ll,48,48 . @ll,112,16 & 0xfff timeout 5s }

because the ethernet protocol is replaced by vlan beforehand,
so we fail to map @ll,48,48 to a vlan protocol.

Likewise, we can't map the vlan info either because we cannot
cope with the 'and' operation properly, nor is it removed.

Prepare for this by deleting and re-adding so that we do not
corrupt the linked list.

After this, the list can be safely changed and a followup patch
can start to delete/reallocate expressions.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 v2: no changes
 src/netlink_delinearize.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 3bdd98d47eb0..3835b3e522b9 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -2539,16 +2539,21 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
 		unsigned int type = expr->dtype->type, ntype = 0;
 		int off = expr->dtype->subtypes;
 		const struct datatype *dtype;
+		LIST_HEAD(tmp);
+		struct expr *n;
 
-		list_for_each_entry(i, &expr->expressions, list) {
+		list_for_each_entry_safe(i, n, &expr->expressions, list) {
 			if (type) {
 				dtype = concat_subtype_lookup(type, --off);
 				expr_set_type(i, dtype, dtype->byteorder);
 			}
+			list_del(&i->list);
 			expr_postprocess(ctx, &i);
+			list_add_tail(&i->list, &tmp);
 
 			ntype = concat_subtype_add(ntype, i->dtype->type);
 		}
+		list_splice(&tmp, &expr->expressions);
 		datatype_set(expr, concat_type_alloc(ntype));
 		break;
 	}
-- 
2.35.1