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Paolo Abeni 18f25dc399 udp: skip L4 aggregation for UDP tunnel packets
If NETIF_F_GRO_FRAGLIST or NETIF_F_GRO_UDP_FWD are enabled, and there
are UDP tunnels available in the system, udp_gro_receive() could end-up
doing L4 aggregation (either SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST) at
the outer UDP tunnel level for packets effectively carrying and UDP
tunnel header.

That could cause inner protocol corruption. If e.g. the relevant
packets carry a vxlan header, different vxlan ids will be ignored/
aggregated to the same GSO packet. Inner headers will be ignored, too,
so that e.g. TCP over vxlan push packets will be held in the GRO
engine till the next flush, etc.

Just skip the SKB_GSO_UDP_L4 and SKB_GSO_FRAGLIST code path if the
current packet could land in a UDP tunnel, and let udp_gro_receive()
do GRO via udp_sk(sk)->gro_receive.

The check implemented in this patch is broader than what is strictly
needed, as the existing UDP tunnel could be e.g. configured on top of
a different device: we could end-up skipping GRO at-all for some packets.

Anyhow, that is a very thin corner case and covering it will add quite
a bit of complexity.

v1 -> v2:
 - hopefully clarify the commit message

Fixes: 9fd1ff5d2a ("udp: Support UDP fraglist GRO/GSO.")
Fixes: 36707061d6 ("udp: allow forwarding of plain (non-fraglisted) UDP GRO packets")
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-30 17:06:49 -07:00
Documentation net: add sysctl for enabling RFC 8335 PROBE messages 2021-03-30 13:29:39 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
arch mips/sgi-ip27: Delete obsolete TODO file 2021-03-30 16:54:49 -07:00
block block: Discard page cache of zone reset target range 2021-03-11 11:49:25 -07:00
certs certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID 2021-01-21 16:16:10 +00:00
crypto crypto: mips/poly1305 - enable for all MIPS processors 2021-03-08 11:52:17 +01:00
drivers ppp: deflate: Remove useless call "zlib_inflateEnd" 2021-03-30 16:59:30 -07:00
fs fs/jffs2: Delete obsolete TODO file 2021-03-30 16:54:49 -07:00
include udp: fixup csum for GSO receive slow path 2021-03-30 17:06:49 -07:00
init Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-03-25 15:31:22 -07:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel sysctl: add proc_dou8vec_minmax() 2021-03-25 17:39:33 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-03-25 15:31:22 -07:00
mm Merge branch 'akpm' (patches from Andrew) 2021-03-25 11:43:43 -07:00
net udp: skip L4 aggregation for UDP tunnel packets 2021-03-30 17:06:49 -07:00
samples Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-03-25 16:30:46 -07:00
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security Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-03-25 15:31:22 -07:00
sound sound fixes for 5.12-rc4 2021-03-19 09:53:32 -07:00
tools selftests: mlxsw: Test vetoing of double sampling 2021-03-29 13:37:26 -07:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM: x86/mmu: Consider the hva in mmu_notifier retry 2021-02-22 13:16:53 -05:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2021-03-25 11:43:43 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Update MCAN MMIO device driver maintainer 2021-03-30 09:31:54 +02:00
Makefile Linux 5.12-rc4 2021-03-21 14:56:43 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
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the problems which may result by upgrading your kernel.