[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <ZuQ5VNo/VUBWbqNl@debian>
Date: Fri, 13 Sep 2024 15:08:36 +0200
From: Guillaume Nault <gnault@...hat.com>
To: Ido Schimmel <idosch@...dia.com>
Cc: netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org,
pabeni@...hat.com, edumazet@...gle.com, dsahern@...nel.org
Subject: Re: [PATCH net-next 0/6] net: fib_rules: Add DSCP selector support
On Wed, Sep 11, 2024 at 12:37:42PM +0300, Ido Schimmel wrote:
> Currently, the kernel rejects IPv4 FIB rules that try to match on the
> upper three DSCP bits:
>
> # ip -4 rule add tos 0x1c table 100
> # ip -4 rule add tos 0x3c table 100
> Error: Invalid tos.
>
> The reason for that is that historically users of the FIB lookup API
> only populated the lower three DSCP bits in the TOS field of the IPv4
> flow key ('flowi4_tos'), which fits the TOS definition from the initial
> IPv4 specification (RFC 791).
>
> This is not very useful nowadays and instead some users want to be able
> to match on the six bits DSCP field, which replaced the TOS and IP
> precedence fields over 25 years ago (RFC 2474). In addition, the current
> behavior differs between IPv4 and IPv6 which does allow users to match
> on the entire DSCP field using the TOS selector.
>
> Recent patchsets made sure that callers of the FIB lookup API now
> populate the entire DSCP field in the IPv4 flow key. Therefore, it is
> now possible to extend FIB rules to match on DSCP.
>
> This is done by adding a new DSCP attribute which is implemented for
> both IPv4 and IPv6 to provide user space programs a consistent behavior
> between both address families.
>
> The behavior of the old TOS selector is unchanged and IPv4 FIB rules
> using it will only match on the lower three DSCP bits. The kernel will
> reject rules that try to use both selectors.
>
> Patch #1 adds the new DSCP attribute but rejects its usage.
>
> Patches #2-#3 implement IPv4 and IPv6 support.
>
> Patch #4 allows user space to use the new attribute.
>
> Patches #5-#6 add selftests.
>
> iproute2 changes can be found here [1].
>
> [1] https://github.com/idosch/iproute2/tree/submit/dscp_rfc_v1
Any reason for always printing numbers in the json output of this
iproute2 RFC? Why can't json users just use the -N parameter?
I haven't checked all the /etc/iproute2/rt_* aliases, but the general
behaviour seems to print the human readable name for both json and
normal outputs, unles -N is given on the command line.
> Ido Schimmel (6):
> net: fib_rules: Add DSCP selector attribute
> ipv4: fib_rules: Add DSCP selector support
> ipv6: fib_rules: Add DSCP selector support
> net: fib_rules: Enable DSCP selector usage
> selftests: fib_rule_tests: Add DSCP selector match tests
> selftests: fib_rule_tests: Add DSCP selector connect tests
>
> include/uapi/linux/fib_rules.h | 1 +
> net/core/fib_rules.c | 4 +-
> net/ipv4/fib_rules.c | 54 ++++++++++-
> net/ipv6/fib6_rules.c | 43 ++++++++-
> tools/testing/selftests/net/fib_rule_tests.sh | 90 +++++++++++++++++++
> 5 files changed, 184 insertions(+), 8 deletions(-)
>
> --
> 2.46.0
>
Powered by blists - more mailing lists