This is a note to let you know that I've just added the patch titled
ip_tunnel: don't force DF when MTU is locked
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ip_tunnel-don-t-force-df-when-mtu-is-locked.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Nov 21 12:16:27 CET 2018
From: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Date: Fri, 16 Nov 2018 16:58:19 +0100
Subject: ip_tunnel: don't force DF when MTU is locked
From: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
[ Upstream commit 16f7eb2b77b55da816c4e207f3f9440a8cafc00a ]
The various types of tunnels running over IPv4 can ask to set the DF
bit to do PMTU discovery. However, PMTU discovery is subject to the
threshold set by the net.ipv4.route.min_pmtu sysctl, and is also
disabled on routes with "mtu lock". In those cases, we shouldn't set
the DF bit.
This patch makes setting the DF bit conditional on the route's MTU
locking state.
This issue seems to be older than git history.
Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Reviewed-by: Stefano Brivio <sbrivio@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/ip_tunnel_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -80,7 +80,7 @@ void iptunnel_xmit(struct sock *sk, stru
iph->version = 4;
iph->ihl = sizeof(struct iphdr) >> 2;
- iph->frag_off = df;
+ iph->frag_off = ip_mtu_locked(&rt->dst) ? 0 : df;
iph->protocol = proto;
iph->tos = tos;
iph->daddr = dst;
Patches currently in stable-queue which might be from sd@xxxxxxxxxxxxxxx are
queue-4.19/ip_tunnel-don-t-force-df-when-mtu-is-locked.patch
