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Commit d6af1a31 authored by Steffen Klassert's avatar Steffen Klassert
Browse files

vti: Add pmtu handling to vti_xmit. 



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

Reported-by: default avatarMark McKinstry <Mark.McKinstry@alliedtelesis.co.nz>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 215276c0

net/ipv4/ip_vti.c

+18 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev, 
	struct dst_entry *dst = skb_dst(skb);

	struct net_device *tdev;	/* Device to other host */

	int err;

	int mtu;



	if (!dst) {

		dev->stats.tx_carrier_errors++;
@@ -192,6 +193,23 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev, 
			tunnel->err_count = 0;

	}



	mtu = dst_mtu(dst);

	if (skb->len > mtu) {

		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);

		if (skb->protocol == htons(ETH_P_IP)) {

			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,

				  htonl(mtu));

		} else {

			if (mtu < IPV6_MIN_MTU)

				mtu = IPV6_MIN_MTU;



			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

		}



		dst_release(dst);

		goto tx_error;

	}



	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));

	skb_dst_set(skb, dst);

	skb->dev = skb_dst(skb)->dev;