4.4-stable review patch. If anyone has any objections, please let me know.
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From: Alexey Kodanev alexey.kodanev@oracle.com
[ Upstream commit 9f2895461439fda2801a7906fb4c5fb3dbb37a0a ]
Before the commit d6990976af7c ("vti6: fix PMTU caching and reporting on xmit") '!skb->ignore_df' check was always true because the function skb_scrub_packet() was called before it, resetting ignore_df to zero.
In the commit, skb_scrub_packet() was moved below, and now this check can be false for the packet, e.g. when sending it in the two fragments, this prevents successful PMTU updates in such case. The next attempts to send the packet lead to the same tx error. Moreover, vti6 initial MTU value relies on PMTU adjustments.
This issue can be reproduced with the following LTP test script: udp_ipsec_vti.sh -6 -p ah -m tunnel -s 2000
Fixes: ccd740cbc6e0 ("vti6: Add pmtu handling to vti6_xmit.") Signed-off-by: Alexey Kodanev alexey.kodanev@oracle.com Acked-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ip6_vti.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -470,7 +470,7 @@ vti6_xmit(struct sk_buff *skb, struct ne }
mtu = dst_mtu(dst); - if (!skb->ignore_df && skb->len > mtu) { + if (skb->len > mtu) { skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu);
if (skb->protocol == htons(ETH_P_IPV6)) {