CDC-NCM: add support for Apple's private interface

Available on iOS/iPadOS >= 17, where this new interface is used by
developer tools using the new RemoteXPC protocol.

This private interface lacks a status endpoint, presumably because there
isn't a physical cable that can be unplugged, nor any speed changes to
be notified about.

Note that NCM interfaces are not exposed until a mode switch is
requested, which macOS does automatically.

The mode switch can be performed like this:

        uint8_t status;
        libusb_control_transfer(device_handle,
                LIBUSB_RECIPIENT_DEVICE | LIBUSB_REQUEST_TYPE_VENDOR |
                LIBUSB_ENDPOINT_IN,
                82, /* bRequest */
                0,  /* wValue   */
                3,  /* wIndex   */
                &status,
                sizeof(status),
                0);

Newer versions of usbmuxd do this automatically.

Co-developed-by: Håvard Sørbø <havard@hsorbo.no>
Signed-off-by: Håvard Sørbø <havard@hsorbo.no>
Signed-off-by: Ole André Vadla Ravnås <oleavr@frida.re>
Link: https://lore.kernel.org/r/20240607074117.31322-1-oleavr@frida.re
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index bf76ecccc2e6aed74473f85b372949e4c5708f0b..d5c47a2a62dcc36391809f93b2774a5af732709d 100644 (file)
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -933,7 +933,8 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
 
        cdc_ncm_find_endpoints(dev, ctx->data);
        cdc_ncm_find_endpoints(dev, ctx->control);
-       if (!dev->in || !dev->out || !dev->status) {
+       if (!dev->in || !dev->out ||
+           (!dev->status && dev->driver_info->flags & FLAG_LINK_INTR)) {
                dev_dbg(&intf->dev, "failed to collect endpoints\n");
                goto error2;
        }
@@ -1925,6 +1926,34 @@ static const struct driver_info cdc_ncm_zlp_info = {
        .set_rx_mode = usbnet_cdc_update_filter,
 };
 
+/* Same as cdc_ncm_info, but with FLAG_SEND_ZLP */
+static const struct driver_info apple_tethering_interface_info = {
+       .description = "CDC NCM (Apple Tethering)",
+       .flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
+                       | FLAG_LINK_INTR | FLAG_ETHER | FLAG_SEND_ZLP,
+       .bind = cdc_ncm_bind,
+       .unbind = cdc_ncm_unbind,
+       .manage_power = usbnet_manage_power,
+       .status = cdc_ncm_status,
+       .rx_fixup = cdc_ncm_rx_fixup,
+       .tx_fixup = cdc_ncm_tx_fixup,
+       .set_rx_mode = usbnet_cdc_update_filter,
+};
+
+/* Same as apple_tethering_interface_info, but without FLAG_LINK_INTR */
+static const struct driver_info apple_private_interface_info = {
+       .description = "CDC NCM (Apple Private)",
+       .flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
+                       | FLAG_ETHER | FLAG_SEND_ZLP,
+       .bind = cdc_ncm_bind,
+       .unbind = cdc_ncm_unbind,
+       .manage_power = usbnet_manage_power,
+       .status = cdc_ncm_status,
+       .rx_fixup = cdc_ncm_rx_fixup,
+       .tx_fixup = cdc_ncm_tx_fixup,
+       .set_rx_mode = usbnet_cdc_update_filter,
+};
+
 /* Same as cdc_ncm_info, but with FLAG_WWAN */
 static const struct driver_info wwan_info = {
        .description = "Mobile Broadband Network Device",
@@ -1954,6 +1983,22 @@ static const struct driver_info wwan_noarp_info = {
 };
 
 static const struct usb_device_id cdc_devs[] = {
+       /* iPhone */
+       { USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x12a8, 2),
+               .driver_info = (unsigned long)&apple_tethering_interface_info,
+       },
+       { USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x12a8, 4),
+               .driver_info = (unsigned long)&apple_private_interface_info,
+       },
+
+       /* iPad */
+       { USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x12ab, 2),
+               .driver_info = (unsigned long)&apple_tethering_interface_info,
+       },
+       { USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x12ab, 4),
+               .driver_info = (unsigned long)&apple_private_interface_info,
+       },
+
        /* Ericsson MBM devices like F5521gw */
        { .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
                | USB_DEVICE_ID_MATCH_VENDOR,