Re: [RFC 1/4] Add usb_get_address and usb_set_address support
From: Oliver Neukum <oneukum@suse.com>
Date: 2019-08-21 09:23:06
Also in:
linux-acpi, linux-usb
Am Dienstag, den 20.08.2019, 22:18 +0000 schrieb Charles.Hyde@dellteam.com:
The core USB driver message.c is missing get/set address functionality
This should go into usbnet. The CDC parser is where it is because it is needed for serial and network devices. As serial devices do not have a MAC, this can go into usbnet.
quoted hunk ↗ jump to hunk
that stops ifconfig from being able to push MAC addresses out to USB based ethernet devices. Without this functionality, some USB devices stop responding to ethernet packets when using ifconfig to change MAC addresses. This has been tested with a Dell Universal Dock D6000. Signed-off-by: Charles Hyde <redacted> Cc: Mario Limonciello <redacted> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-usb@vger.kernel.org --- drivers/usb/core/message.c | 59 ++++++++++++++++++++++++++++++++++++++ include/linux/usb.h | 3 ++ 2 files changed, 62 insertions(+)diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 5adf489428aa..eea775234b09 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c@@ -1085,6 +1085,65 @@ int usb_clear_halt(struct usb_device *dev, int pipe) } EXPORT_SYMBOL_GPL(usb_clear_halt); +/** + * usb_get_address - + * @dev: device whose endpoint is halted
Which endpoint?
+ * @mac: buffer for containing + * Context: !in_interrupt () + * + * This will attempt to get the six byte MAC address from a USB device's + * ethernet controller using GET_NET_ADDRESS command. + * + * This call is synchronous, and may not be used in an interrupt context. + * + * Return: Zero on success, or else the status code returned by the
Well, I am afraid it will return 6 on success.
+ * underlying usb_control_msg() call.
+ */
+int usb_get_address(struct usb_device *dev, unsigned char * mac)
+{
+ int ret = -ENOMEM;Initialization is unnecessary here.
+ unsigned char *tbuf = kmalloc(256, GFP_NOIO);
If you intentionally picked a safety margin of 42 times, this is cool. Otherwise it is a litttle much.
+ + if (!tbuf) + return -ENOMEM; + + ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), + USB_CDC_GET_NET_ADDRESS, + USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE, + 0, USB_REQ_SET_ADDRESS, tbuf, 256, + USB_CTRL_GET_TIMEOUT); + if (ret == 6) + memcpy(mac, tbuf, 6);
You cannot ignore the case of devices sending more or less than 6 bytes. Regards Oliver