From: Herbert Xu <[EMAIL PROTECTED]>
Date: Tue, 18 Jul 2006 23:04:04 +1000
> Actually, I plan to differentiate between RX CHECKSUM_HW and TX
> CHECKSUM_HW. Now that we have things like Xen it is possible for
> RX packets to have patial checksums too.
>
> When this is done loopback can send TX CH
On Tue, Jul 18, 2006 at 04:54:39PM +0400, Alexey Kuznetsov wrote:
>
> I preferred optimistic approach: if the checksum comes out correct,
> we do not really care, how device calculated it. Probably, it calculated
> checksum over wrong data, but got a good checksum. So what? It is
> not a crypto dig
Hello!
> The whole point of CHECKSUM_UNNECESSARY is that the hardware parses
> the protocol header for us. So in this case it must calculate the
> checksum for only the first 8 bytes of the payload.
I remember this place, I stalled there for a minute ages ago.
He is right in his doubts, the pla
On Tue, Jul 18, 2006 at 09:09:34AM +0800, Wei Yongjun wrote:
>
> And in my test, UDP under IPv4 maybe do that.
> My UDP packet is:
>
> packet1:
> ___
> | Source Port | Dest Port |
> |_|_|
> | Length =
On Monday 17 July 2006 08:17, Herbert Xu wrote:
> Wei Yongjun <[EMAIL PROTECTED]> wrote:
> > So if I want to trim a skb, I think I must do a checksum even if
the
> > skb->ip_summed is CHECKSUM_UNNECESSARY.
>
> Nope. CHECKSUM_UNNECESSARY means that the hardware has already
> verified the checksum
Wei Yongjun <[EMAIL PROTECTED]> wrote:
>
> So if I want to trim a skb, I think I must do a checksum even if the
> skb->ip_summed is CHECKSUM_UNNECESSARY.
Nope. CHECKSUM_UNNECESSARY means that the hardware has already
verified the checksum to be correct for the given protocol.
Trimming a packet d
Since network device can auto calculate and verify the checksum of a
packet, for example: some e1000 interface. Different device will set
different value of skb->ip_summed.
a) If device do nothing to checksum, skb->ip_summed would be set to
CHECKSUM_NONE.
b) If device can only calculate a che
