ipaddress: Simplify vf_info parsing

Commit 7b8179c780a1a ("iproute2: Add new command to ip link to
enable/disable VF spoof check") tried to add support for
IFLA_VF_SPOOFCHK in a backwards-compatible manner, but aparently overdid
it: parse_rtattr_nested() handles missing attributes perfectly fine in
that it will leave the relevant field unassigned so calling code can
just compare against NULL. There is no need to layback from the previous
(IFLA_VF_TX_RATE) attribute to the next to check if IFLA_VF_SPOOFCHK is
present or not. To the contrary, it establishes a potentially incorrect
assumption of these two attributes directly following each other which
may not be the case (although up to now, kernel aligns them this way).

This patch cleans up the code to adhere to the common way of checking
for attribute existence. It has been tested to return correct results
regardless of whether the kernel exports IFLA_VF_SPOOFCHK or not.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Greg Rose <grose@lightfleet.com>
1 file changed