@@ -587,7 +587,8 @@ int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
EXPORT_SYMBOL(ip_tunnel_encap);
static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
- struct rtable *rt, __be16 df)
+ struct rtable *rt, __be16 df,
+ const struct iphdr *inner_iph)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
int pkt_size = skb->len - tunnel->hlen - dev->hard_header_len;
@@ -604,7 +605,8 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
if (skb->protocol == htons(ETH_P_IP)) {
if (!skb_is_gso(skb) &&
- (df & htons(IP_DF)) && mtu < pkt_size) {
+ (inner_iph->frag_off & htons(IP_DF)) &&
+ mtu < pkt_size) {
memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
return -E2BIG;
@@ -738,7 +740,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
goto tx_error;
}
- if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off)) {
+ if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off, inner_iph)) {
ip_rt_put(rt);
goto tx_error;
}
This is a note to let you know that I have just added a patch titled ip_tunnel: fix ipv4 pmtu check to honor inner ip header df to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt5. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 1ac842056de79f4ebdfcb734e1af942dceaf9da6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Timo=20Ter=C3=A4s?= <timo.teras@iki.fi> Date: Tue, 7 Jul 2015 08:34:13 +0300 Subject: ip_tunnel: fix ipv4 pmtu check to honor inner ip header df MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit fc24f2b2094366da8786f59f2606307e934cea17 upstream. Frag needed should be sent only if the inner header asked to not fragment. Currently fragmentation is broken if the tunnel has df set, but df was not asked in the original packet. The tunnel's df needs to be still checked to update internally the pmtu cache. Commit 23a3647bc4f93bac broke it, and this commit fixes the ipv4 df check back to the way it was. Fixes: 23a3647bc4f93bac ("ip_tunnels: Use skb-len to PMTU check.") Cc: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Timo Teräs <timo.teras@iki.fi> Acked-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- net/ipv4/ip_tunnel.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) -- 1.9.1