❦ 29 mars 2017 22:47 +0200, Vincent Bernat [off-list ref] :

Parsing of neighbor discovery options is done earlier to ignore the
whole packet in case of a malformed option. Moreover, the assumption the
skb was linear is removed and options are extracted with
skb_header_pointer() as well. The check on the source link-layer address
option is also more strict (for Ethernet, we expect the length field to
be 1).

There is some parsing implemented in net/ipv6/ndisc.c, notably
ndisc_parse_options(). I don't know if this is a good idea to reuse
that: it may have the expectation that some IP processing has already
been done (for example, the IPv6 length has already been checked, the
SKB is expected to be linear).
-- 
Watch out for off-by-one errors.
            - The Elements of Programming Style (Kernighan & Plauger)