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From: Louis DeLosSantos <louis.delos.devel@gmail.com>
To: bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: Martin KaFai Lau <martin.lau@linux.dev>,
	 Stanislav Fomichev <sdf@google.com>,
	razor@blackwall.org,  John Fastabend <john.fastabend@gmail.com>,
	Yonghong Song <yhs@meta.com>,
	 Louis DeLosSantos <louis.delos.devel@gmail.com>
Subject: [PATCH v2 0/2] bpf: utilize table ID in bpf_fib_lookup helper
Date: Wed, 31 May 2023 15:38:47 -0400	[thread overview]
Message-ID: <20230505-bpf-add-tbid-fib-lookup-v2-0-0a31c22c748c@gmail.com> (raw)

This patchset adds the ability to specify a table ID to the
`bpf_fib_lookup` BPF helper. 

A new `tbid` field is added to `struct fib_bpf_lookup`.
When the `fib_bpf_lookup` helper is called with the `BPF_FIB_LOOKUP_DIRECT` and 
`BPF_FIB_LOOKUP_TBID' flag the `tbid` field will be interpreted as the table ID 
to use for the fib lookup.

If the `tbid` specifies a table that does not exist the lookup fails

This functionality is useful in containerized environments. 

For instance, if a CNI wants to dictate the next-hop for traffic leaving
a container it can create a container-specific routing table and perform
a fib lookup against this table in a "host-net-namespace-side" TC program.

This functionality also allows `ip rule` like functionality at the TC
layer, allowing an eBPF program to pick a routing table based on some
aspect of the sk_buff.

As a concrete use case, this feature will be used in Cilium's SRv6 L3VPN
When egress traffic leaves a Pod an eBPF program attached by Cilium will
determine which VRF the egress traffic should target, and then perform a
FIB lookup in a specific table representing this VRF's FIB.

The existing `fib_lookup.c` bpf selftest was appended several test cases
to ensure this feature works as expected. 

$ sudo ./test_progs -a "*fib*"

Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Louis DeLosSantos <louis.delos.devel@gmail.com>
Changes in v2:
- Utilize a new flag `BPF_FIB_LOOKUP_TBID` for performing table ID fib
- Update fib lookup selftest to reflect new flag usage.
- Change second commit message subject to `selftests/bpf`.
- Link to v1: https://lore.kernel.org/r/20230505-bpf-add-tbid-fib-lookup-v1-0-fd99f7162e76@gmail.com

Louis DeLosSantos (2):
      bpf: add table ID to bpf_fib_lookup BPF helper
      selftests/bpf: test table ID fib lookup BPF helper

 include/uapi/linux/bpf.h                           | 21 ++++++--
 net/core/filter.c                                  | 14 ++++-
 tools/include/uapi/linux/bpf.h                     | 21 ++++++--
 .../testing/selftests/bpf/prog_tests/fib_lookup.c  | 61 +++++++++++++++++++---
 4 files changed, 102 insertions(+), 15 deletions(-)
base-commit: fbc0b0253001c397a481d258a88ce5f08996574f
change-id: 20230505-bpf-add-tbid-fib-lookup-aa46fa098603

Best regards,
Louis DeLosSantos <louis.delos.devel@gmail.com>

             reply	other threads:[~2023-05-31 19:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-31 19:38 Louis DeLosSantos [this message]
2023-05-31 19:38 ` [PATCH v2 1/2] bpf: add table ID to bpf_fib_lookup BPF helper Louis DeLosSantos
2023-05-31 19:38 ` [PATCH v2 2/2] selftests/bpf: test table ID fib lookup " Louis DeLosSantos
2023-06-01 18:07 ` [PATCH v2 0/2] bpf: utilize table ID in bpf_fib_lookup helper Daniel Borkmann
2023-06-01 18:10 ` patchwork-bot+netdevbpf

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