Commits
Bjørn Mork committed 5b8f15f78e6
net: cdc_mbim: handle IPv6 Neigbor Solicitations MBIM is a point-to-point protocol transporting raw IP packets with no L2 headers. Only IPv4 and IPv6 are supported. ARP in particular is not, which is quite logical given the lack of L2 headers. The driver still emulates an ethernet interface, dropping all unsupported protocols, and avoiding neigbour resolving by setting the IFF_NOARP flag. The MBIM specification does not explicitly forbid IPv6 Neighbor Discovery, and it seems the other OS support will respond to Neighbor Solicitations on MBIM links. There are therefore buggy devices out there, which despite the pointlessness, still require Neighbor Discovery for IPv6 over MBIM. This is incompatible with the IFF_NOARP flag which disables both ARP and ND. We cannot support ARP in any case, so we have to keep that flag. This patch implements a workaround for the buggy devices, letting the driver respond directly to Neighbor Solicitations from the device. This is not optimal, but will have minimal effect on any sane device. Cc: Greg Suarez <gsuarez@smithmicro.com> Reported-and-tested-by: Thomas Schäfer <tschaefer@t-online.de> Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>