From cff78b77d409445b0490e67bf9329e69e0bbc872 Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Thu, 9 Feb 2023 10:27:57 +0100
Subject: [PATCH] netlink_delinearize: allow postprocessing on concatenated
 elements

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2094887
Upstream Status: nftables commit 0542a431e8dcc

commit 0542a431e8dccfa86fa5b1744f536e61a0b204f3
Author: Florian Westphal <fw@strlen.de>
Date:   Tue Jun 14 21:57:58 2022 +0200

    netlink_delinearize: allow postprocessing on concatenated elements

    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>

Signed-off-by: Phil Sutter <psutter@redhat.com>
---
 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 068c3bb..2f13990 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -2538,16 +2538,21 @@ 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;
 	}
-- 
2.39.1