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: 52a589d51f ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff44 ("vxlan: update skb dst pmtu on tx path")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stefano Brivio 2018-10-12 23:53:59 +02:00 committed by David S. Miller
parent 7463e4f9b9
commit 6b4f92af3d
3 changed files with 15 additions and 6 deletions

View file

@ -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) {

View file

@ -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);

View file

@ -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 */