netdev - [PATCH ipsec] xfrmi: drop ignore_df check before updating pmtu

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Date:   Tue,  4 Aug 2020 11:37:29 +0200
From:   Sabrina Dubroca <sd@...asysnail.net>
To:     netdev@...r.kernel.org
Cc:     steffen.klassert@...unet.com, Sabrina Dubroca <sd@...asysnail.net>,
        Xiumei Mu <xmu@...hat.com>
Subject: [PATCH ipsec] xfrmi: drop ignore_df check before updating pmtu

xfrm interfaces currently test for !skb->ignore_df when deciding
whether to update the pmtu on the skb's dst. Because of this, no pmtu
exception is created when we do something like:

    ping -s 1438 <dest>

By dropping this check, the pmtu exception will be created and the
next ping attempt will work.

Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
Reported-by: Xiumei Mu <xmu@...hat.com>
Signed-off-by: Sabrina Dubroca <sd@...asysnail.net>
---
 net/xfrm/xfrm_interface.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index b615729812e5..ade2eba863b3 100644
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -292,7 +292,7 @@ xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 	}
 
 	mtu = dst_mtu(dst);
-	if (!skb->ignore_df && skb->len > mtu) {
+	if (skb->len > mtu) {
 		skb_dst_update_pmtu_no_confirm(skb, mtu);
 
 		if (skb->protocol == htons(ETH_P_IPV6)) {
-- 
2.27.0