[PATCH v13] gro: fix reordering of packets in GRO layer
胡嘉瑜
hujiayu.hu at foxmail.com
Tue Jan 16 15:28:16 CET 2024
在 2024/1/9 上午12:04, Kumara Parameshwaran 写道:
> In the current implementation when a packet is received with
> special TCP flag(s) set, only that packet is delivered out of order.
> There could be already coalesced packets in the GRO table
> belonging to the same flow but not delivered.
> This fix makes sure that the entire segment is delivered with the
> special flag(s) set which is how the Linux GRO is also implemented
>
> Signed-off-by: Kumara Parameshwaran <kumaraparamesh92 at gmail.com>
> ---
> If the received packet is not a pure ACK packet, we check if
> there are any previous packets in the flow, if present we indulge
> the received packet also in the coalescing logic and update the flags
> of the last recived packet to the entire segment which would avoid
> re-ordering.
>
> Lets say a case where P1(PSH), P2(ACK), P3(ACK) are received in burst mode,
> P1 contains PSH flag and since it does not contain any prior packets in the flow
> we copy it to unprocess_packets and P2(ACK) and P3(ACK) are merged together.
> In the existing case the P2,P3 would be delivered as single segment first and the
> unprocess_packets will be copied later which will cause reordering. With the patch
> copy the unprocess packets first and then the packets from the GRO table.
>
> Testing done
> The csum test-pmd was modified to support the following
> GET request of 10MB from client to server via test-pmd (static arp entries added in client
> and server). Enable GRO and TSO in test-pmd where the packets recived from the client mac
> would be sent to server mac and vice versa.
> In above testing, without the patch the client observerd re-ordering of 25 packets
> and with the patch there were no packet re-ordering observerd.
>
> v2:
> Fix warnings in commit and comment.
> Do not consider packet as candidate to merge if it contains SYN/RST flag.
>
> v3:
> Fix warnings.
>
> v4:
> Rebase with master.
>
> v5:
> Adding co-author email
> v6:
> Address review comments from the maintainer to restructure the code
> and handle only special flags PSH,FIN
>
> v7:
> Fix warnings and errors
>
> v8:
> Fix warnings and errors
>
> v9:
> Fix commit message
>
> v10:
> Update tcp header flags and address review comments
>
> v11:
> Fix warnings
>
> v12:
> Fix nit review comments
>
> v13:
> Fix warnings
>
> lib/gro/gro_tcp.h | 9 +++++++++
> lib/gro/gro_tcp4.c | 36 +++++++++++++++++++++++++++---------
> lib/gro/gro_tcp_internal.h | 2 +-
> lib/gro/gro_vxlan_tcp4.c | 5 +++--
> 4 files changed, 40 insertions(+), 12 deletions(-)
>
Reviewed-by: Jiayu Hu <hujiayu.hu at foxmail.com>
Thanks,
Jiayu
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