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Commit 5228ddc9 authored by Rusty Russell's avatar Rusty Russell Committed by David S. Miller
Browse files

tun: TUNSETFEATURES to set gso features. 



ethtool is useful for setting (some) device fields, but it's
root-only.  Finer feature control is available through a tun-specific
ioctl.

(Includes Mark McLoughlin <markmc@redhat.com>'s fix to hold rtnl sem).

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Acked-by: default avatarMax Krasnyansky <maxk@qualcomm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 07240fd0

drivers/net/tun.c

+49 −0
Original line number Diff line number Diff line
@@ -611,6 +611,46 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) 
	return err;

}



/* 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)

{

	unsigned int 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));



	if (arg & TUN_F_CSUM) {

		features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;

		arg &= ~TUN_F_CSUM;



		if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {

			if (arg & TUN_F_TSO_ECN) {

				features |= NETIF_F_TSO_ECN;

				arg &= ~TUN_F_TSO_ECN;

			}

			if (arg & TUN_F_TSO4)

				features |= NETIF_F_TSO;

			if (arg & TUN_F_TSO6)

				features |= NETIF_F_TSO6;

			arg &= ~(TUN_F_TSO4|TUN_F_TSO6);

		}

	}



	/* This gives the user a way to test for new features in future by

	 * trying to set them. */

	if (arg)

		return -EINVAL;



	dev->features = features;

	if (old_features != dev->features)

		netdev_features_change(dev);



	return 0;

}



static int tun_chr_ioctl(struct inode *inode, struct file *file,

			 unsigned int cmd, unsigned long arg)

{
@@ -715,6 +755,15 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file, 
		break;

#endif



	case TUNSETOFFLOAD:

	{

		int ret;

		rtnl_lock();

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

		rtnl_unlock();

		return ret;

	}



	case SIOCGIFFLAGS:

		ifr.ifr_flags = tun->if_flags;

		if (copy_to_user( argp, &ifr, sizeof ifr))

include/linux/if_tun.h

+7 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#define TUNSETLINK    _IOW('T', 205, int)

#define TUNSETGROUP   _IOW('T', 206, int)

#define TUNGETFEATURES _IOR('T', 207, unsigned int)

#define TUNSETOFFLOAD _IOW('T', 208, unsigned int)



/* TUNSETIFF ifr flags */

#define IFF_TUN		0x0001
@@ -48,6 +49,12 @@ 
#define IFF_NO_PI	0x1000

#define IFF_ONE_QUEUE	0x2000



/* Features for GSO (TUNSETOFFLOAD). */

#define TUN_F_CSUM	0x01	/* You can hand me unchecksummed packets. */

#define TUN_F_TSO4	0x02	/* I can handle TSO for IPv4 packets */

#define TUN_F_TSO6	0x04	/* I can handle TSO for IPv6 packets */

#define TUN_F_TSO_ECN	0x08	/* I can handle TSO with ECN bits. */



struct tun_pi {

	unsigned short flags;

	__be16 proto;