net: add NDOs for configuring hardware timestamping

Current hardware timestamping API for NICs requires implementing
.ndo_eth_ioctl() for SIOCGHWTSTAMP and SIOCSHWTSTAMP.

That API has some boilerplate such as request parameter translation
between user and kernel address spaces, handling possible translation
failures correctly, etc. Since it is the same all across the board, it
would be desirable to handle it through generic code.

Here we introduce .ndo_hwtstamp_get() and .ndo_hwtstamp_set(), which
implement that boilerplate and allow drivers to just act upon requests.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Maxim Georgiev <glipus@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://lore.kernel.org/r/20230801142824.1772134-2-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 44 insertions, 2 deletions

diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 3730945ee294..10c0e173b38b 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -254,11 +254,32 @@ static int dev_eth_ioctl(struct net_device *dev,
 
 static int dev_get_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 {
-	return dev_eth_ioctl(dev, ifr, SIOCGHWTSTAMP);
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct kernel_hwtstamp_config kernel_cfg = {};
+	struct hwtstamp_config cfg;
+	int err;
+
+	if (!ops->ndo_hwtstamp_get)
+		return dev_eth_ioctl(dev, ifr, SIOCGHWTSTAMP); /* legacy */
+
+	if (!netif_device_present(dev))
+		return -ENODEV;
+
+	err = ops->ndo_hwtstamp_get(dev, &kernel_cfg);
+	if (err)
+		return err;
+
+	hwtstamp_config_from_kernel(&cfg, &kernel_cfg);
+
+	if (copy_to_user(ifr->ifr_data, &cfg, sizeof(cfg)))
+		return -EFAULT;
+
+	return 0;
 }
 
 static int dev_set_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 {
+	const struct net_device_ops *ops = dev->netdev_ops;
 	struct kernel_hwtstamp_config kernel_cfg;
 	struct netlink_ext_ack extack = {};
 	struct hwtstamp_config cfg;
@@ -280,7 +301,28 @@ static int dev_set_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 		return err;
 	}
 
-	return dev_eth_ioctl(dev, ifr, SIOCSHWTSTAMP);
+	if (!ops->ndo_hwtstamp_set)
+		return dev_eth_ioctl(dev, ifr, SIOCSHWTSTAMP); /* legacy */
+
+	if (!netif_device_present(dev))
+		return -ENODEV;
+
+	err = ops->ndo_hwtstamp_set(dev, &kernel_cfg, &extack);
+	if (err) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
+		return err;
+	}
+
+	/* The driver may have modified the configuration, so copy the
+	 * updated version of it back to user space
+	 */
+	hwtstamp_config_from_kernel(&cfg, &kernel_cfg);
+
+	if (copy_to_user(ifr->ifr_data, &cfg, sizeof(cfg)))
+		return -EFAULT;
+
+	return 0;
 }
 
 static int dev_siocbond(struct net_device *dev,