Commit c7c1abfd authored by Eyal Birger's avatar Eyal Birger Committed by Steffen Klassert
Browse files

vti: fix ipv4 pmtu check to honor ip header df 



Frag needed should only be sent if the header enables DF.

This fix allows packets larger than MTU to pass the vti interface
and be fragmented after encapsulation, aligning behavior with
non-vti xfrm.

Fixes: d6af1a31 ("vti: Add pmtu handling to vti_xmit.")
Signed-off-by: default avatarEyal Birger <eyal.birger@gmail.com>
Reviewed-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 8fc0e3b6

net/ipv4/ip_vti.c

+4 −2
Original line number Diff line number Diff line
@@ -218,7 +218,7 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev, 
	}



	if (dst->flags & DST_XFRM_QUEUE)

		goto queued;

		goto xmit;



	if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {

		dev->stats.tx_carrier_errors++;
@@ -238,6 +238,8 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev, 
	if (skb->len > mtu) {

		skb_dst_update_pmtu_no_confirm(skb, mtu);

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

			if (!(ip_hdr(skb)->frag_off & htons(IP_DF)))

				goto xmit;

			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,

				  htonl(mtu));

		} else {
@@ -251,7 +253,7 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev, 
		goto tx_error;

	}



queued:

xmit:

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

	skb_dst_set(skb, dst);

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