diff mbox

ip_tunnel: fix ipv4 pmtu check to honor inner ip header df

Message ID 1436171750-6029-1-git-send-email-timo.teras@iki.fi
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Timo Teras July 6, 2015, 8:35 a.m. UTC 
Frag needed should be sent only if the inner header asked
to not fragment. Currently fragmentation is broken if the
tunnel has df set. The tunnel's df needs to be still checked
to update internally the pmtu cache.

This got broken in commit 23a3647bc4f93bac and this fixes
the pmtu check back to the way it was.

Fixes: 23a3647bc4f93bac ("ip_tunnels: Use skb-len to PMTU check.")
Cc: Pravin B Shelar <pshelar@nicira.com>
---
Should go to -stable queues (3.12.y and never).

 net/ipv4/ip_tunnel.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Comments

Pravin B Shelar July 6, 2015, 8:26 p.m. UTC | #1 
On Mon, Jul 6, 2015 at 1:35 AM, Timo Teräs <timo.teras@iki.fi> wrote:
> Frag needed should be sent only if the inner header asked
> to not fragment. Currently fragmentation is broken if the
> tunnel has df set. The tunnel's df needs to be still checked
> to update internally the pmtu cache.
>
> This got broken in commit 23a3647bc4f93bac and this fixes
> the pmtu check back to the way it was.
>
> Fixes: 23a3647bc4f93bac ("ip_tunnels: Use skb-len to PMTU check.")
> Cc: Pravin B Shelar <pshelar@nicira.com>

Patch looks good, But commit msg is missing Signed-off-by: tag.
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diff mbox

Patch

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 0bb8e14..6822572 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -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;
 	}