diff mbox

vti6: Add pmtu handling to vti6_xmit.

Message ID 20150529182709.2147.78230.stgit@ahduyck-vm-fedora22
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Alexander Duyck May 29, 2015, 6:28 p.m. UTC 
From: Steffen Klassert <steffen.klassert@secunet.com>

We currently rely on the PMTU discovery of xfrm.
However if a packet is localy sent, the PMTU mechanism
of xfrm tries to to local socket notification what
might not work for applications like ping that don't
check for this. So add pmtu handling to vti6_xmit to
report MTU changes immediately.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---

So this version is slightly modified to cover the IPv4 case in addition to
the IPv6 case.  With this patch I was able to run netperf over either an
IPv4 or IPv6 address routed over the ip6_vti tunnel.

 net/ipv6/ip6_vti.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

David Miller June 1, 2015, 11:04 p.m. UTC | #1 
From: Alexander Duyck <alexander.h.duyck@redhat.com>
Date: Fri, 29 May 2015 11:28:26 -0700

> From: Steffen Klassert <steffen.klassert@secunet.com>
> 
> We currently rely on the PMTU discovery of xfrm.
> However if a packet is localy sent, the PMTU mechanism
> of xfrm tries to to local socket notification what
> might not work for applications like ping that don't
> check for this. So add pmtu handling to vti6_xmit to
> report MTU changes immediately.
> 
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>

Applied, thanks Andrew.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index d25209657edc..3b5c1ea50d2f 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -435,6 +435,7 @@  vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 	struct net_device *tdev;
 	struct xfrm_state *x;
 	int err = -1;
+	int mtu;
 
 	if (!dst)
 		goto tx_err_link_failure;
@@ -468,6 +469,19 @@  vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 	skb_dst_set(skb, dst);
 	skb->dev = skb_dst(skb)->dev;
 
+	mtu = dst_mtu(dst);
+	if (!skb->ignore_df && skb->len > mtu) {
+		skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu);
+
+		if (skb->protocol == htons(ETH_P_IPV6))
+			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+		else
+			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+				  htonl(mtu));
+
+		return -EMSGSIZE;
+	}
+
 	err = dst_output(skb);
 	if (net_xmit_eval(err) == 0) {
 		struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats);