f036e68212
The TOS value that is returned to user space in the route get reply is
the one with which the lookup was performed ('fl4->flowi4_tos'). This is
fine when the matched route is configured with a TOS as it would not
match if its TOS value did not match the one with which the lookup was
performed.
However, matching on TOS is only performed when the route's TOS is not
zero. It is therefore possible to have the kernel incorrectly return a
non-zero TOS:
# ip link add name dummy1 up type dummy
# ip address add 192.0.2.1/24 dev dummy1
# ip route get fibmatch 192.0.2.2 tos 0xfc
192.0.2.0/24 tos 0x1c dev dummy1 proto kernel scope link src 192.0.2.1
Fix by instead returning the DSCP field from the FIB result structure
which was populated during the route lookup.
Output after the patch:
# ip link add name dummy1 up type dummy
# ip address add 192.0.2.1/24 dev dummy1
# ip route get fibmatch 192.0.2.2 tos 0xfc
192.0.2.0/24 dev dummy1 proto kernel scope link src 192.0.2.1
Extend the existing selftests to not only verify that the correct route
is returned, but that it is also returned with correct "tos" value (or
without it).
Fixes: b61798130f1b ("net: ipv4: RTM_GETROUTE: return matched fib result when requested")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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.