bpf: BPF-helper for MTU checking add length input

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The FIB lookup example[1] show how the IP-header field tot_len
(iph->tot_len) is used as input to perform the MTU check.

This patch extend the BPF-helper bpf_check_mtu() with the same ability
to provide the length as user parameter input, via mtu_len parameter.

This still needs to be done before the bpf_check_mtu() helper API
becomes frozen.

  [1] samples/bpf/xdp_fwd_kern.c

Fixes: 34b2021cc6 ("bpf: Add BPF-helper for MTU checking")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/161521555850.3515614.6533850861569774444.stgit@firesoul

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Jesper Dangaard Brouer 2021-03-08 15:59:18 +01:00 • committed by Daniel Borkmann

parent e7fb6465d4

commit e5e35e754c

2 changed files with 21 additions and 7 deletions

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include/uapi/linux/bpf.h

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