On Thu, Dec 12, 2013 at 05:38:59PM +0900, Simon Horman wrote:
> If VLAN acceleration is used when the kernel receives a packet
> then the outer-most VLAN tag will not be present in the packet
> when it is received by netdev-linux. Rather, it will be present
> in auxdata.
>
> This patch uses recvmsg() instead of recv() to read auxdata for
> each packet and if the vlan_tid is set then it is added to the packet.
>
> Adding the vlan_tid makes use of headroom available
> in the buffer parameter of rx_recv.
>
> Signed-off-by: Simon Horman <ho...@verge.net.au>
> @@ -803,7 +811,7 @@ netdev_linux_rx_construct(struct netdev_rx *rx_)
> memset(&sll, 0, sizeof sll);
> sll.sll_family = AF_PACKET;
> sll.sll_ifindex = ifindex;
> - sll.sll_protocol = (OVS_FORCE unsigned short int) htons(ETH_P_ALL);
> + sll.sll_protocol = htons(ETH_P_ALL);
I was surprised that this didn't raise a sparse warning, but it doesn't.
Great.
In netdev_linux_rx_recv_sock(), I think we might want to
ofpbuf_reserve() VLAN_HEADER_LEN bytes at the beginning, to ensure that
there is headroom to insert a VLAN header. On the other hand, that
would mean that we lose four bytes of tailroom that are important if the
VLAN header is actually embedded in the packet. I think that means that
we should advise callers to supply 4 bytes of space beyond what they
think they need.
I don't think the cast here, or in netdev_linux_rx_recv(), is necessary:
> + } else if ((size_t)retval > size) {
> + errno = EMSGSIZE;
> + return -1;
> + }
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