Subject: Re: [BUG] sky2 broken for Yukon PCI-E Gigabit Ethernet Controller 11ab:4362 (rev 19)

From: Patrick McHardy <[email-masked]>
Date: Fri, 27 Jan 2006 16:28:25 +0100

Herbert Xu wrote:
> On Fri, Jan 27, 2006 at 07:07:34AM +0100, Knut Petersen wrote:
> 
>>Well, there are no problems if SuSEfirewall2 is disabled. But have a look
>>at the loaded modules:
>>
>>ipt_MASQUERADE          3968  1
>>pppoe                  15360  2
>>pppox                   4616  1 pppoe
> 
> 
> OK, although we can't rule out sky2/netfilter from the enquiry, I've
> identified two bugs in ppp/pppoe that may be responsible for what you
> are seeing.  So please try the following patch and let us know if the
> problem still exists (or deteriorates/improves).
> 
> [PPP]: Fixed hardware RX checksum handling
> 
> When we pull the PPP protocol off the skb, we forgot to update the
> hardware RX checksum.  This may lead to messages such as
> 
> 	dsl0: hw csum failure.
> 
> Similarly, we need to clear the hardware checksum flag when we use
> the existing packet to store the decompressed result.

We had a couple of reports of incorrect hardware checksums with
PPPoE. KdF, can you test Herbert's patch (attached again to this
mail) please?
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -1610,6 +1610,8 @@ ppp_receive_nonmp_frame(struct ppp *ppp,
 		}
 		else if (!pskb_may_pull(skb, skb->len))
 			goto err;
+		else
+			skb->ip_summed = CHECKSUM_NONE;
 
 		len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
 		if (len <= 0) {
@@ -1690,6 +1692,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp,
 			kfree_skb(skb);
 		} else {
 			skb_pull(skb, 2);	/* chop off protocol */
+			skb_postpull_rcsum(skb, skb->data - 2, 2);
 			skb->dev = ppp->dev;
 			skb->protocol = htons(npindex_to_ethertype[npi]);
 			skb->mac.raw = skb->data;