# Re: \[PATCH v6\] bonding support for IPv6 transmit hashing

- From: John Eaglesham \<hidden\>
- Date: 2012-07-03 05:01:21 
- List: netdev
- Page: https://ratatoskr.run/netdev/2012/07/10898753
- Thread: https://ratatoskr.run/netdev/2012/07/10898591/t.md

```text
On 7/2/2012 4:33 PM, Jay Vosburgh wrote:
>> +
>> +		(((hash >> 24) XOR (hash >> 16) XOR (hash >> 8) XOR hash)
>> +			(source MAC XOR destination MAC))
>> +				modulo slave count
>
> 	This seems to be missing an XOR, between the end of "XOR hash)"
> and the start of "(source MAC".
>

You're correct.

>> 	if (skb->protocol == htons(ETH_P_IP)) {
>> +		iph = ip_hdr(skb);
>> 		if (!ip_is_fragment(iph) &&
>> -		    (iph->protocol == IPPROTO_TCP ||
>> -		     iph->protocol == IPPROTO_UDP)) {
>> +			(iph->protocol == IPPROTO_TCP ||
>> +			iph->protocol == IPPROTO_UDP)) {
>
> 	Why did these two lines change?
>

I replaced the mixed tabs and spaces with all tabs when I updated that function, but in retrospect the tabs and spaces were likely intentional. I will revert.

>> +			layer4hdr = (__be16 *)((u32 *)iph + iph->ihl);
>> +			if (iph->ihl * sizeof(u32) + sizeof(__be16) * 2 >
>> +				skb_headlen(skb) - skb_network_offset(skb))
>> +				goto short_header;
>> 			layer4_xor = ntohs((*layer4hdr ^ *(layer4hdr + 1)));
>> +		} else if (skb_network_header_len(skb) < sizeof(struct iphdr)) {
>> +			goto short_header;
>> 		}
>> -		return (layer4_xor ^
>> -			((ntohl(iph->saddr ^ iph->daddr)) & 0xffff)) % count;
>> -
>> +		return (layer4_xor ^ ((ntohl(iph->saddr ^ iph->daddr)) & 0xffff)) % count;
>
> 	This line runs past 80 columns.  There are a few more of these
> further down.
>

I will double-check this.

>> +	} else if (skb->protocol == htons(ETH_P_IPV6)) {
>> +		ipv6h = ipv6_hdr(skb);
>> +		if (ipv6h->nexthdr == IPPROTO_TCP || ipv6h->nexthdr == IPPROTO_UDP) {
>> +			layer4hdr = (__be16 *)((u8 *)ipv6h + sizeof(struct ipv6hdr));
>
> 	Could this be written as
>
> 			layer4hdr = (__be16 *)(ipv6h + 1);
>
> 	instead?
>
> 	-J
>

Yes, I can make that change. Thanks.

John
```