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Commit 88255375 authored by Michał Mirosław's avatar Michał Mirosław Committed by David S. Miller
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net: tun: convert to hw_features 



This changes offload setting behaviour to what I think is correct:
 - offloads set via ethtool mean what admin wants to use (by default
   he wants 'em all)
 - offloads set via ioctl() mean what userspace is expecting to get
   (this limits which admin wishes are granted)
 - TUN_NOCHECKSUM is ignored, as it might cause broken packets when
   forwarded (ip_summed == CHECKSUM_UNNECESSARY means that checksum
   was verified, not that it can be ignored)

If TUN_NOCHECKSUM is implemented, it should set skb->csum_* and
skb->ip_summed (= CHECKSUM_PARTIAL) for known protocols and let others
be verified by kernel when necessary.

TUN_NOCHECKSUM handling was introduced by commit
f43798c2:

    tun: Allow GSO using virtio_net_hdr

Signed-off-by: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 47103041

drivers/net/tun.c

+25 −38
Original line number Diff line number Diff line
@@ -123,6 +123,9 @@ struct tun_struct { 
	gid_t			group;



	struct net_device	*dev;

	u32			set_features;

#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \

			  NETIF_F_TSO6|NETIF_F_UFO)

	struct fasync_struct	*fasync;



	struct tap_filter       txflt;
@@ -451,12 +454,20 @@ tun_net_change_mtu(struct net_device *dev, int new_mtu) 
	return 0;

}



static u32 tun_net_fix_features(struct net_device *dev, u32 features)

{

	struct tun_struct *tun = netdev_priv(dev);



	return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);

}



static const struct net_device_ops tun_netdev_ops = {

	.ndo_uninit		= tun_net_uninit,

	.ndo_open		= tun_net_open,

	.ndo_stop		= tun_net_close,

	.ndo_start_xmit		= tun_net_xmit,

	.ndo_change_mtu		= tun_net_change_mtu,

	.ndo_fix_features	= tun_net_fix_features,

};



static const struct net_device_ops tap_netdev_ops = {
@@ -465,6 +476,7 @@ static const struct net_device_ops tap_netdev_ops = { 
	.ndo_stop		= tun_net_close,

	.ndo_start_xmit		= tun_net_xmit,

	.ndo_change_mtu		= tun_net_change_mtu,

	.ndo_fix_features	= tun_net_fix_features,

	.ndo_set_multicast_list	= tun_net_mclist,

	.ndo_set_mac_address	= eth_mac_addr,

	.ndo_validate_addr	= eth_validate_addr,
@@ -628,8 +640,7 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, 
			kfree_skb(skb);

			return -EINVAL;

		}

	} else if (tun->flags & TUN_NOCHECKSUM)

		skb->ip_summed = CHECKSUM_UNNECESSARY;

	}



	switch (tun->flags & TUN_TYPE_MASK) {

	case TUN_TUN_DEV:
@@ -1094,6 +1105,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 
				goto err_free_sk;

		}



		dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |

			TUN_USER_FEATURES;

		dev->features = dev->hw_features;



		err = register_netdevice(tun->dev);

		if (err < 0)

			goto err_free_sk;
@@ -1158,18 +1173,12 @@ static int tun_get_iff(struct net *net, struct tun_struct *tun, 


/* This is like a cut-down ethtool ops, except done via tun fd so no

 * privs required. */

static int set_offload(struct net_device *dev, unsigned long arg)

static int set_offload(struct tun_struct *tun, unsigned long arg)

{

	u32 old_features, features;



	old_features = dev->features;

	/* Unset features, set them as we chew on the arg. */

	features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST

				    |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6

				    |NETIF_F_UFO));

	u32 features = 0;



	if (arg & TUN_F_CSUM) {

		features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;

		features |= NETIF_F_HW_CSUM;

		arg &= ~TUN_F_CSUM;



		if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
@@ -1195,9 +1204,8 @@ static int set_offload(struct net_device *dev, unsigned long arg) 
	if (arg)

		return -EINVAL;



	dev->features = features;

	if (old_features != dev->features)

		netdev_features_change(dev);

	tun->set_features = features;

	netdev_update_features(tun->dev);



	return 0;

}
@@ -1262,12 +1270,9 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 


	case TUNSETNOCSUM:

		/* Disable/Enable checksum */

		if (arg)

			tun->flags |= TUN_NOCHECKSUM;

		else

			tun->flags &= ~TUN_NOCHECKSUM;



		tun_debug(KERN_INFO, tun, "checksum %s\n",

		/* [unimplemented] */

		tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",

			  arg ? "disabled" : "enabled");

		break;
@@ -1316,7 +1321,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 
		break;

#endif

	case TUNSETOFFLOAD:

		ret = set_offload(tun->dev, arg);

		ret = set_offload(tun, arg);

		break;



	case TUNSETTXFILTER:
@@ -1595,30 +1600,12 @@ static void tun_set_msglevel(struct net_device *dev, u32 value) 
#endif

}



static u32 tun_get_rx_csum(struct net_device *dev)

{

	struct tun_struct *tun = netdev_priv(dev);

	return (tun->flags & TUN_NOCHECKSUM) == 0;

}



static int tun_set_rx_csum(struct net_device *dev, u32 data)

{

	struct tun_struct *tun = netdev_priv(dev);

	if (data)

		tun->flags &= ~TUN_NOCHECKSUM;

	else

		tun->flags |= TUN_NOCHECKSUM;

	return 0;

}



static const struct ethtool_ops tun_ethtool_ops = {

	.get_settings	= tun_get_settings,

	.get_drvinfo	= tun_get_drvinfo,

	.get_msglevel	= tun_get_msglevel,

	.set_msglevel	= tun_set_msglevel,

	.get_link	= ethtool_op_get_link,

	.get_rx_csum	= tun_get_rx_csum,

	.set_rx_csum	= tun_set_rx_csum

};