Go to file
Ido Schimmel 2d300ce0b7 net: fib_rules: Fix iif / oif matching on L3 master device
Before commit 40867d74c3 ("net: Add l3mdev index to flow struct and
avoid oif reset for port devices") it was possible to use FIB rules to
match on a L3 domain. This was done by having a FIB rule match on iif /
oif being a L3 master device. It worked because prior to the FIB rule
lookup the iif / oif fields in the flow structure were reset to the
index of the L3 master device to which the input / output device was
enslaved to.

The above scheme made it impossible to match on the original input /
output device. Therefore, cited commit stopped overwriting the iif / oif
fields in the flow structure and instead stored the index of the
enslaving L3 master device in a new field ('flowi_l3mdev') in the flow
structure.

While the change enabled new use cases, it broke the original use case
of matching on a L3 domain. Fix this by interpreting the iif / oif
matching on a L3 master device as a match against the L3 domain. In
other words, if the iif / oif in the FIB rule points to a L3 master
device, compare the provided index against 'flowi_l3mdev' rather than
'flowi_{i,o}if'.

Before cited commit, a FIB rule that matched on 'iif vrf1' would only
match incoming traffic from devices enslaved to 'vrf1'. With the
proposed change (i.e., comparing against 'flowi_l3mdev'), the rule would
also match traffic originating from a socket bound to 'vrf1'. Avoid that
by adding a new flow flag ('FLOWI_FLAG_L3MDEV_OIF') that indicates if
the L3 domain was derived from the output interface or the input
interface (when not set) and take this flag into account when evaluating
the FIB rule against the flow structure.

Avoid unnecessary checks in the data path by detecting that a rule
matches on a L3 master device when the rule is installed and marking it
as such.

Tested using the following script [1].

Output before 40867d74c3 (v5.4.291):

default dev dummy1 table 100 scope link
default dev dummy1 table 200 scope link

Output after 40867d74c374:

default dev dummy1 table 300 scope link
default dev dummy1 table 300 scope link

Output with this patch:

default dev dummy1 table 100 scope link
default dev dummy1 table 200 scope link

[1]
 #!/bin/bash

 ip link add name vrf1 up type vrf table 10
 ip link add name dummy1 up master vrf1 type dummy

 sysctl -wq net.ipv4.conf.all.forwarding=1
 sysctl -wq net.ipv4.conf.all.rp_filter=0

 ip route add table 100 default dev dummy1
 ip route add table 200 default dev dummy1
 ip route add table 300 default dev dummy1

 ip rule add prio 0 oif vrf1 table 100
 ip rule add prio 1 iif vrf1 table 200
 ip rule add prio 2 table 300

 ip route get 192.0.2.1 oif dummy1 fibmatch
 ip route get 192.0.2.1 iif dummy1 from 198.51.100.1 fibmatch

Fixes: 40867d74c3 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices")
Reported-by: hanhuihui <hanhuihui5@huawei.com>
Closes: https://lore.kernel.org/netdev/ec671c4f821a4d63904d0da15d604b75@huawei.com/
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250414172022.242991-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-15 17:54:56 -07:00
Documentation netlink: specs: ovs_vport: align with C codegen capabilities 2025-04-14 14:05:56 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
arch xen: branch for v6.15-rc2 2025-04-10 07:04:23 -07:00
block treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push fixes reverts the multibuffer hash testing as it is buggy. 2025-04-02 09:14:59 -07:00
drivers eth: bnxt: fix missing ring index trim on error path 2025-04-15 17:38:42 -07:00
fs CRC cleanups for 6.15 2025-04-08 12:09:28 -07:00
include net: fib_rules: Fix iif / oif matching on L3 master device 2025-04-15 17:54:56 -07:00
init Miscellaneous scheduler fixes/updates: 2025-04-06 10:44:58 -07:00
io_uring io_uring/kbuf: reject zero sized provided buffers 2025-04-07 07:51:23 -06:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel Probes fixes for v6.14: 2025-04-08 12:51:34 -07:00
lib CRC cleanups for 6.15 2025-04-08 12:09:28 -07:00
mm Disable SLUB_TINY for build testing 2025-04-06 10:00:04 -07:00
net net: fib_rules: Fix iif / oif matching on L3 master device 2025-04-15 17:54:56 -07:00
rust Kbuild updates for v6.15 2025-04-05 15:46:50 -07:00
samples treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
scripts Disable SLUB_TINY for build testing 2025-04-06 10:00:04 -07:00
security mseal sysmap: kernel config and header change 2025-04-01 15:17:14 -07:00
sound soundwire fix for 6.15-rc1 2025-04-06 12:04:53 -07:00
tools selftests/tc-testing: Add test for echo of big TC filters 2025-04-11 16:33:32 -07:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt ARM: 2025-04-08 13:47:55 -07:00
.clang-format clang-format: Update with v6.11-rc1's `for_each` macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: Create intermediate vmlinux build with relocations preserved 2025-03-17 00:29:50 +09:00
.mailmap mailmap: add an entry for Nicolas Schier 2025-04-01 15:20:45 -07:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Including fixes from netfilter. 2025-04-04 09:15:35 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Just a handful of fixes, notably 2025-04-11 16:38:04 -07:00
Makefile kbuild: Add '-fno-builtin-wcslen' 2025-04-08 12:03:26 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

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 reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.