On 03/26/2013 11:06 PM, Eric Dumazet wrote:
> 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.
Yes, skb_set_partial_csum()
> You should add this code in a helper as well.
Ok
> Because its not clear at this point if csum_start/csum_offset/ip_summed
> are consistent.
Since David has applied the seires, will send patches on top.
Thanks
>
>
>
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