From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Mon, 23 Mar 2020 19:53:10 +0100
Subject: netfilter: nft_fwd_netdev: allow to redirect to ifb via ingress
Patch-mainline: v5.6
Git-commit: bcfabee1afd99484b6ba067361b8678e28bbc065
References: bsc#1176447

Set skb->tc_redirected to 1, otherwise the ifb driver drops the packet.
Set skb->tc_from_ingress to 1 to reinject the packet back to the ingress
path after leaving the ifb egress path.

This patch inconditionally sets on these two skb fields that are
meaningful to the ifb driver. The existing forward action is guaranteed
to run from ingress path.

Fixes: 39e6dea28adc ("netfilter: nf_tables: add forward expression to the netdev family")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/netfilter/nft_fwd_netdev.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/net/netfilter/nft_fwd_netdev.c
+++ b/net/netfilter/nft_fwd_netdev.c
@@ -28,6 +28,10 @@ static void nft_fwd_netdev_eval(const st
 	struct nft_fwd_netdev *priv = nft_expr_priv(expr);
 	int oif = regs->data[priv->sreg_dev];
 
+	/* These are used by ifb only. */
+	pkt->skb->tc_redirected = 1;
+	pkt->skb->tc_from_ingress = 1;
+
 	nf_fwd_netdev_egress(pkt, oif);
 	regs->verdict.code = NF_STOLEN;
 }