lkml.org 
[lkml]   [2024]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH net v4 1/2] net: gro: fix udp bad offset in socket lookup by adding {inner_}network_offset to napi_gro_cb
Richard Gobert wrote:
> Commits a602456 ("udp: Add GRO functions to UDP socket") and 57c67ff ("udp:
> additional GRO support") introduce incorrect usage of {ip,ipv6}_hdr in the
> complete phase of gro. The functions always return skb->network_header,
> which in the case of encapsulated packets at the gro complete phase, is
> always set to the innermost L3 of the packet. That means that calling
> {ip,ipv6}_hdr for skbs which completed the GRO receive phase (both in
> gro_list and *_gro_complete) when parsing an encapsulated packet's _outer_
> L3/L4 may return an unexpected value.
>
> This incorrect usage leads to a bug in GRO's UDP socket lookup.
> udp{4,6}_lib_lookup_skb functions use ip_hdr/ipv6_hdr respectively. These
> *_hdr functions return network_header which will point to the innermost L3,
> resulting in the wrong offset being used in __udp{4,6}_lib_lookup with
> encapsulated packets.
>
> This patch adds network_offset and inner_network_offset to napi_gro_cb, and
> makes sure both are set correctly.
>
> To fix the issue, network_offsets union is used inside napi_gro_cb, in
> which both the outer and the inner network offsets are saved.
>
> Reproduction example:
>
> Endpoint configuration example (fou + local address bind)
>
> # ip fou add port 6666 ipproto 4
> # ip link add name tun1 type ipip remote 2.2.2.1 local 2.2.2.2 encap fou encap-dport 5555 encap-sport 6666 mode ipip
> # ip link set tun1 up
> # ip a add 1.1.1.2/24 dev tun1
>
> Netperf TCP_STREAM result on net-next before patch is applied:
>
> net-next main, GRO enabled:
> $ netperf -H 1.1.1.2 -t TCP_STREAM -l 5
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 131072 16384 16384 5.28 2.37
>
> net-next main, GRO disabled:
> $ netperf -H 1.1.1.2 -t TCP_STREAM -l 5
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 131072 16384 16384 5.01 2745.06
>
> patch applied, GRO enabled:
> $ netperf -H 1.1.1.2 -t TCP_STREAM -l 5
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 131072 16384 16384 5.01 2877.38
>
> Fixes: 57c67ff4bd92 ("udp: additional GRO support")
> Signed-off-by: Richard Gobert <richardbgobert@gmail.com>

Reviewed-by: Willem de Bruijn <willemb@google.com>

\
 
 \ /
  Last update: 2024-05-27 18:09    [W:0.043 / U:0.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site