otto_l2_nexthop_add() fails when the gateway finds no free L2 slot, or,
where the next hop has to exist already (RTL930x), when the gateway's
address has not been learnt. The route then still forwards, through
the L2 index it held before, or index 0 on its first update.
Let it trap instead. RTL930x behaves as before: the call fails before
it writes nh->port, which stays port_ignore, so no_port already traps
the route. On RTL839x the PIE rule forwards whatever the route says
until the rules can trap, so nothing changes there either.
Not tested on hardware: no failed next hop write was provoked.
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Gennaro Cimmino <gcimmino@rayonra.net>
Link: https://github.com/openwrt/openwrt/pull/25805
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Gennaro Cimmino
011e33d47f