[dpdk-dev] [PATCH v2] gso: fix pyld_unit_size issue for udp gso
Hu, Jiayu
jiayu.hu at intel.com
Thu Sep 17 04:16:05 CEST 2020
Acked-by: Jiayu Hu <jiayu.hu at intel.com>
> -----Original Message-----
> From: yang_y_yi at 163.com <yang_y_yi at 163.com>
> Sent: Thursday, September 17, 2020 10:13 AM
> To: dev at dpdk.org
> Cc: Hu, Jiayu <jiayu.hu at intel.com>; thomas at monjalon.net;
> yangyi01 at inspur.com; yang_y_yi at 163.com
> Subject: [PATCH v2] gso: fix pyld_unit_size issue for udp gso
>
> From: Yi Yang <yangyi01 at inspur.com>
>
> Fragment offset of IPv4 header is measured in units of
> 8 bytes. Fragment offset of UDP fragments will be wrong
> after GSO if pyld_unit_size isn't multiple of 8. Say
> pyld_unit_size is 1500, fragment offset of the second
> UDP fragment will be 187 (i.e. 1500 / 8), which means 1496,
> and it will result in 4-byte data loss (1500 - 1496 = 4).
> So UDP GRO will reassemble out a wrong packet.
>
> Fixes: b166d4f30b66 ("gso: support UDP/IPv4 fragmentation")
>
> Signed-off-by: Yi Yang <yangyi01 at inspur.com>
> ---
> lib/librte_gso/gso_udp4.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_gso/gso_udp4.c b/lib/librte_gso/gso_udp4.c
> index 21fea09..6fa68f2 100644
> --- a/lib/librte_gso/gso_udp4.c
> +++ b/lib/librte_gso/gso_udp4.c
> @@ -69,7 +69,10 @@
> return 1;
> }
>
> - pyld_unit_size = gso_size - hdr_offset;
> + /* pyld_unit_size must be a multiple of 8 because frag_off
> + * uses 8 bytes as unit.
> + */
> + pyld_unit_size = (gso_size - hdr_offset) & ~7U;
>
> /* Segment the payload */
> ret = gso_do_segment(pkt, hdr_offset, pyld_unit_size, direct_pool,
> --
> 1.8.3.1
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