On Tue, 2013-03-26 at 14:19 +0800, Jason Wang wrote:
> Set the transport header for 1) some drivers (e.g ixgbe) needs l4 header 2)
> precise packet length estimation (introduced in 1def9238) needs l4 header to
> compute header length.
>
> For the packets with partial checksum, the patch just set the transport header
> to csum_start. Otherwise tries to use skb_flow_dissect() to get l4 offset, if
> it
> fails, just pretend no l4 header.
>
> Cc: Eric Dumazet <eduma...@google.com>
> Signed-off-by: Jason Wang <jasow...@redhat.com>
> ---
> drivers/net/macvtap.c | 9 +++++++++
> 1 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index a449439..acf6450 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -21,6 +21,7 @@
> #include <net/rtnetlink.h>
> #include <net/sock.h>
> #include <linux/virtio_net.h>
> +#include <net/flow_keys.h>
>
> /*
> * A macvtap queue is the central object of this driver, it connects
> @@ -645,6 +646,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q,
> struct msghdr *m,
> int vnet_hdr_len = 0;
> int copylen = 0;
> bool zerocopy = false;
> + struct flow_keys keys;
>
> if (q->flags & IFF_VNET_HDR) {
> vnet_hdr_len = q->vnet_hdr_sz;
> @@ -725,6 +727,13 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q,
> struct msghdr *m,
> goto err_kfree;
> }
>
> + if (skb->ip_summed == CHECKSUM_PARTIAL)
where ip_summed is set to this value ?
> + skb_set_transport_header(skb, skb_checksum_start_offset(skb));
> + else if (skb_flow_dissect(skb, &keys))
> + skb_set_transport_header(skb, keys.thoff);
> + else
> + skb_set_transport_header(skb, ETH_HLEN);
> +
> rcu_read_lock_bh();
> vlan = rcu_dereference_bh(q->vlan);
> /* copy skb_ubuf_info for callback when skb has no error */
This driver has nice helpers.
You should add this code in a helper as well.
Because its not clear at this point if csum_start/csum_offset/ip_summed
are consistent.
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