Re: [PATCH] usbnet: ipheth: fix connectivity with iOS 14

From: Jakub Kicinski
Date: Sat Nov 21 2020 - 17:03:14 EST


On Thu, 19 Nov 2020 18:24:39 +0100 Yves-Alexis Perez wrote:
> Starting with iOS 14 released in September 2020, connectivity using the
> personal hotspot USB tethering function of iOS devices is broken.
>
> Communication between the host and the device (for example ICMP traffic
> or DNS resolution using the DNS service running in the device itself)
> works fine, but communication to endpoints further away doesn't work.
>
> Investigation on the matter shows that UDP and ICMP traffic from the
> tethered host is reaching the Internet at all. For TCP traffic there are
> exchanges between tethered host and server but packets are modified in
> transit leading to impossible communication.
>
> After some trials Matti Vuorela discovered that reducing the URB buffer
> size by two bytes restored the previous behavior. While a better
> solution might exist to fix the issue, since the protocol is not
> publicly documented and considering the small size of the fix, let's do
> that.
>
> Tested-by: Matti Vuorela <matti.vuorela@xxxxxxxxxxxx>
> Signed-off-by: Yves-Alexis Perez <corsac@xxxxxxxxxx>
> Link: https://lore.kernel.org/linux-usb/CAAn0qaXmysJ9vx3ZEMkViv_B19ju-_ExN8Yn_uSefxpjS6g4Lw@xxxxxxxxxxxxxx/
> Link: https://github.com/libimobiledevice/libimobiledevice/issues/1038

Applied to net with the typo fixed, thanks!