Hello,

On Tue, 28 Aug 2012, Jesper Dangaard Brouer wrote:

On Mon, 2012-08-27 at 18:20 +0300, Julian Anastasov wrote:

quoted

quoted

@@ -956,8 +963,11 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 
 	/* MTU checking: Special for tunnel mode */
-	if (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr) &&

I guess:
 ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr)
Is the same as:
 skb->len

	I think so. You can think of this in different way:
all transmitters are called from same place, there is no
difference in the packets we see. When we can use
__mtu_check_toobig_v6 for other methods relying on skb->len
being correct, we can do the same for tunnels, only that
tunnels have lower MTU, that is the only difference.

quoted

quoted

-	    !skb_is_gso(skb)) {
+	if ((!IP6CB(skb)->frag_max_size &&
+	     (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr) &&
+	      !skb_is_gso(skb)))
+	    || IP6CB(skb)->frag_max_size + sizeof(struct ipv6hdr) > mtu) {

quoted

	mtu is already reduced with the new outer header size,
may be we can just call __mtu_check_toobig_v6 with mtu?

To Julian, is the extra sizeof(struct ipv6hdr) addition to
frag_max_size, wrong? (as the mtu is already reduced)

	Yes, sizeof(struct ipv6hdr) is needed only together
with payload_len because payload_len does not include the
first header.

If above statements hold, I think we can simply use
__mtu_check_toobig_v6() also for the tunnel case :-)

	Yep

--Jesper

Regards

--
Julian Anastasov [off-list ref]