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Date: Thu, 4 Oct 2012 09:43:33 -0700 From: Stephen Hemminger <shemminger@...tta.com> To: Jesse Gross <jesse@...ira.com> Cc: davem@...emloft.net, netdev@...r.kernel.org Subject: Re: [RFC] vxlan: use ether header as fallback hash On Thu, 4 Oct 2012 09:27:14 -0700 Jesse Gross <jesse@...ira.com> wrote: > On Wed, Oct 3, 2012 at 9:39 PM, Stephen Hemminger <shemminger@...tta.com> wrote: > > VXLAN bases source UDP port based on flow to help the > > receiver to be able to load balance based on outer header > > contents. > > > > This patches changes the algorithm to better handle packets > > that can not be categorized by the rxhash() function. > > It adds a fallback to use jhash on the Ether header. > > > > It also fixes a bug where the old code could assign 0 as a port > > value. > > > > > > Signed-off-by: Stephen Hemminger <shemminger@...tta.com> > > > > --- > > RFC for now, compile tested only > > > > --- a/drivers/net/vxlan.c 2012-10-03 21:25:43.747968165 -0700 > > +++ b/drivers/net/vxlan.c 2012-10-03 21:36:10.213805422 -0700 > > @@ -622,12 +622,30 @@ static inline u8 vxlan_ecn_encap(u8 tos, > > return INET_ECN_encapsulate(tos, inner); > > } > > > > +/* Compute hash to use for source port > > + * first choice to use L4 flow hash since it will spread > > + * better and maybe available from hardware > > + * secondary choice is to use jhash on the Ethernet header > > + * Always returns non-zero value > > + */ > > +static u16 vxlan_flow_hash(struct sk_buff *skb) > > +{ > > + u16 hash = skb_get_rxhash(skb); > > + > > + if (!hash) > > + hash = jhash(skb->data, 3, skb->protocol); > > Shouldn't this be jhash2 for words? No. for a couple of reasons. First, the ethernet header may not be aligned. Second we want to get source/destination and type. The source/destination is 12 bytes (3 words) and the ether type is already in skb->protocol. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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