linux.git/net/ipv6/ip6_offload.c, branch v6.9

net: gro: fix udp bad offset in socket lookup by adding {inner_}network_offset to napi_gro_cb

2024-05-02T09:02:48+00:00

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: a6024562ffd7 ("udp: Add GRO functions to UDP socket")
Signed-off-by: Richard Gobert 
Reviewed-by: Eric Dumazet 
Reviewed-by: Willem de Bruijn 
Signed-off-by: Paolo Abeni

net: move ip_packet_offload and ipv6_packet_offload to net_hotdata

2024-03-08T05:12:42+00:00

These structures are used in GRO and GSO paths.

v2: ipv6_packet_offload definition depends on CONFIG_INET

Signed-off-by: Eric Dumazet 
Acked-by: Soheil Hassas Yeganeh 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20240306160031.874438-7-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: gro: parse ipv6 ext headers without frag0 invalidation

2024-01-05T16:11:49+00:00

The existing code always pulls the IPv6 header and sets the transport
offset initially. Then optionally again pulls any extension headers in
ipv6_gso_pull_exthdrs and sets the transport offset again on return from
that call. skb->data is set at the start of the first extension header
before calling ipv6_gso_pull_exthdrs, and must disable the frag0
optimization because that function uses pskb_may_pull/pskb_pull instead of
skb_gro_ helpers. It sets the GRO offset to the TCP header with
skb_gro_pull and sets the transport header. Then returns skb->data to its
position before this block.

This commit introduces a new helper function - ipv6_gro_pull_exthdrs -
which is used in ipv6_gro_receive to pull ipv6 ext headers instead of
ipv6_gso_pull_exthdrs. Thus, there is no modification of skb->data, all
operations use skb_gro_* helpers, and the frag0 fast path can be taken for
IPv6 packets with ext headers.

Signed-off-by: Richard Gobert 
Reviewed-by: Willem de Bruijn 
Reviewed-by: David Ahern 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/504130f6-b56c-4dcc-882c-97942c59f5b7@gmail.com
Signed-off-by: Jakub Kicinski

net: gso: add HBH extension header offload support

2024-01-05T16:11:49+00:00

This commit adds net_offload to IPv6 Hop-by-Hop extension headers (as it
is done for routing and dstopts) since it is supported in GSO and GRO.
This allows to remove specific HBH conditionals in GSO and GRO when
pulling and parsing an incoming packet.

Signed-off-by: Richard Gobert 
Reviewed-by: Willem de Bruijn 
Reviewed-by: David Ahern 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/d4f8825a-1d55-4b12-9d67-a254dbbfa6ae@gmail.com
Signed-off-by: Jakub Kicinski

net: move gso declarations and functions to their own files

2023-06-10T07:11:41+00:00

Move declarations into include/net/gso.h and code into net/core/gso.c

Signed-off-by: Eric Dumazet 
Cc: Stanislav Fomichev 
Reviewed-by: Simon Horman 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20230608191738.3947077-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver

2022-12-12T23:41:44+00:00

IPv6/TCP and GRO stacks can build big TCP packets with an added
temporary Hop By Hop header.

Is GSO is not involved, then the temporary header needs to be removed in
the driver. This patch provides a generic helper for drivers that need
to modify their headers in place.

Tested:
Compiled and ran with ethtool -K eth1 tso off
Could send Big TCP packets

Signed-off-by: Coco Li 
Link: https://lore.kernel.org/r/20221210041646.3587757-1-lixiaoyan@google.com
Signed-off-by: Jakub Kicinski

net-next: skbuff: refactor pskb_pull

2022-09-30T11:31:46+00:00

pskb_may_pull already contains all of the checks performed by
pskb_pull.
Use pskb_may_pull for validation in pskb_pull, eliminating the
duplication and making __pskb_pull obsolete.
Replace __pskb_pull with pskb_pull where applicable.

Signed-off-by: Richard Gobert 
Signed-off-by: David S. Miller

net-next: gro: Fix use of skb_gro_header_slow

2022-09-20T09:47:25+00:00

In the cited commit, the function ipv6_gro_receive was accidentally
changed to use skb_gro_header_slow, without attempting the fast path.
Fix it.

Fixes: 35ffb6654729 ("net: gro: skb_gro_header helper function")
Signed-off-by: Richard Gobert 
Link: https://lore.kernel.org/r/20220911184835.GA105063@debian
Signed-off-by: Paolo Abeni

net: gro: skb_gro_header helper function

2022-08-25T08:33:21+00:00

Introduce a simple helper function to replace a common pattern.
When accessing the GRO header, we fetch the pointer from frag0,
then test its validity and fetch it from the skb when necessary.

This leads to the pattern
skb_gro_header_fast -> skb_gro_header_hard -> skb_gro_header_slow
recurring many times throughout GRO code.

This patch replaces these patterns with a single inlined function
call, improving code readability.

Signed-off-by: Richard Gobert 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20220823071034.GA56142@debian
Signed-off-by: Paolo Abeni

ipv6/gro: insert temporary HBH/jumbo header

2022-05-16T09:18:56+00:00

Following patch will add GRO_IPV6_MAX_SIZE, allowing gro to build
BIG TCP ipv6 packets (bigger than 64K).

This patch changes ipv6_gro_complete() to insert a HBH/jumbo header
so that resulting packet can go through IPv6/TCP stacks.

Signed-off-by: Eric Dumazet 
Acked-by: Alexander Duyck 
Signed-off-by: David S. Miller