From f33d9e2b48a34e1558b67a473a1fc1d6e793f93c Mon Sep 17 00:00:00 2001
From: Yves-Alexis Perez <corsac@corsac.net>
Date: Thu, 19 Nov 2020 18:24:39 +0100
Subject: [PATCH] usbnet: ipheth: fix connectivity with iOS 14
Git-commit: f33d9e2b48a34e1558b67a473a1fc1d6e793f93c
Patch-mainline: v5.10-rc6
References: git-fixes
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 no 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
Link: https://lore.kernel.org/r/20201119172439.94988-1-corsac@corsac.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/net/usb/ipheth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c
index b09b45382faf..207e59e74935 100644
--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -59,7 +59,7 @@
#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)
--
2.26.2