Commit 6b4f92af authored by Stefano Brivio's avatar Stefano Brivio Committed by David S. Miller
Browse files

geneve, vxlan: Don't set exceptions if skb->len < mtu 



We shouldn't abuse exceptions: if the destination MTU is already higher
than what we're transmitting, no exception should be created.

Fixes: 52a589d5 ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff ("vxlan: update skb dst pmtu on tx path")
Signed-off-by: default avatarStefano Brivio <sbrivio@redhat.com>
Reviewed-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7463e4f9

drivers/net/geneve.c

+3 −4
Original line number Diff line number Diff line
@@ -830,8 +830,8 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
	if (IS_ERR(rt))

		return PTR_ERR(rt);



	skb_dst_update_pmtu(skb, dst_mtu(&rt->dst) -

				 GENEVE_IPV4_HLEN - info->options_len);

	skb_tunnel_check_pmtu(skb, &rt->dst,

			      GENEVE_IPV4_HLEN + info->options_len);



	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);

	if (geneve->collect_md) {
@@ -872,8 +872,7 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
	if (IS_ERR(dst))

		return PTR_ERR(dst);



	skb_dst_update_pmtu(skb, dst_mtu(dst) -

				 GENEVE_IPV6_HLEN - info->options_len);

	skb_tunnel_check_pmtu(skb, dst, GENEVE_IPV6_HLEN + info->options_len);



	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);

	if (geneve->collect_md) {

drivers/net/vxlan.c

+2 −2
Original line number Diff line number Diff line
@@ -2194,7 +2194,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, 
		}



		ndst = &rt->dst;

		skb_dst_update_pmtu(skb, dst_mtu(ndst) - VXLAN_HEADROOM);

		skb_tunnel_check_pmtu(skb, ndst, VXLAN_HEADROOM);



		tos = ip_tunnel_ecn_encap(tos, old_iph, skb);

		ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);
@@ -2231,7 +2231,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, 
				goto out_unlock;

		}



		skb_dst_update_pmtu(skb, dst_mtu(ndst) - VXLAN6_HEADROOM);

		skb_tunnel_check_pmtu(skb, ndst, VXLAN6_HEADROOM);



		tos = ip_tunnel_ecn_encap(tos, old_iph, skb);

		ttl = ttl ? : ip6_dst_hoplimit(ndst);

include/net/dst.h

+10 −0
Original line number Diff line number Diff line
@@ -527,4 +527,14 @@ static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu) 
		dst->ops->update_pmtu(dst, NULL, skb, mtu);

}



static inline void skb_tunnel_check_pmtu(struct sk_buff *skb,

					 struct dst_entry *encap_dst,

					 int headroom)

{

	u32 encap_mtu = dst_mtu(encap_dst);



	if (skb->len > encap_mtu - headroom)

		skb_dst_update_pmtu(skb, encap_mtu - headroom);

}



#endif /* _NET_DST_H */

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