generic: ipeth: fix iOS 14 tethering

This fixes tethering with devices using iOS 14. Prior to this patch,
connections to remote endpoints were not possible while data transfers
between the OpenWrt device and the iOS endpoints worked fine.

Signed-off-by: David Bauer <mail@david-bauer.net>
(cherry picked from commit f64496f30f)
This commit is contained in:
David Bauer 2020-11-29 19:14:05 +01:00
parent bdc2f19f9d
commit d0b8be75ff

View File

@ -0,0 +1,44 @@
From: Yves-Alexis Perez <corsac@corsac.net>
Subject: [PATCH] usbnet: ipheth: fix connectivity with iOS 14
Date: Thu, 19 Nov 2020 18:24:39 +0100
Archived-At: <https://lore.kernel.org/stable/20201119172439.94988-1-corsac@corsac.net/>
List-Post: <mailto:stable@vger.kernel.org>
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@bitfactor.fi>
Signed-off-by: Yves-Alexis Perez <corsac@corsac.net>
Link: https://lore.kernel.org/linux-usb/CAAn0qaXmysJ9vx3ZEMkViv_B19ju-_ExN8Yn_uSefxpjS6g4Lw@mail.gmail.com/
Link: https://github.com/libimobiledevice/libimobiledevice/issues/1038
Cc: stable@vger.kernel.org
---
drivers/net/usb/ipheth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -70,7 +70,7 @@
#define IPHETH_USBINTF_SUBCLASS 253
#define IPHETH_USBINTF_PROTO 1
-#define IPHETH_BUF_SIZE 1516
+#define IPHETH_BUF_SIZE 1514
#define IPHETH_IP_ALIGN 2 /* padding at front of URB */
#define IPHETH_TX_TIMEOUT (5 * HZ)