bpf: Add mtu checking to FIB forwarding helper

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Add check that egress MTU can handle packet to be forwarded. If
the MTU is less than the packet length, return 0 meaning the
packet is expected to continue up the stack for help - eg.,
fragmenting the packet or sending an ICMP.

The XDP path needs to leverage the FIB entry for an MTU on the
route spec or an exception entry for a given destination. The
skb path lets is_skb_forwardable decide if the packet can be
sent.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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David Ahern 2018-05-21 09:08:15 -07:00 • committed by Daniel Borkmann

parent 901731b882

commit 4f74fede40

1 changed files with 35 additions and 7 deletions

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net/core/filter.c

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