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Commit 274038f8 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by David S. Miller
Browse files

tun: Report "persist" flag to userspace 



The TUN_PERSIST flag is not reported at all -- both TUNGETIFF, and sysfs
"flags" attribute skip one. Knowing whether a device is persistent or not
is critical for checkpoint-restore, thus I propose to add the read-only
IFF_PERSIST one for this.

Setting this new IFF_PERSIST is hardly possible, as TUNSETIFF doesn't check
for unknown flags being zero and thus there can be trash.

Signed-off-by: default avatarPavel Emelyanov <xemul@parallels.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7c0cadc6

drivers/net/tun.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -1530,6 +1530,9 @@ static int tun_flags(struct tun_struct *tun) 
	if (tun->flags & TUN_TAP_MQ)

	if (tun->flags & TUN_TAP_MQ)

		flags |= IFF_MULTI_QUEUE;

		flags |= IFF_MULTI_QUEUE;





	if (tun->flags & TUN_PERSIST)

		flags |= IFF_PERSIST;



	return flags;

	return flags;

}

}

include/uapi/linux/if_tun.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -68,6 +68,8 @@ 
#define IFF_MULTI_QUEUE 0x0100

#define IFF_MULTI_QUEUE 0x0100

#define IFF_ATTACH_QUEUE 0x0200

#define IFF_ATTACH_QUEUE 0x0200

#define IFF_DETACH_QUEUE 0x0400

#define IFF_DETACH_QUEUE 0x0400

/* read-only flag */

#define IFF_PERSIST	0x0800





/* Features for GSO (TUNSETOFFLOAD). */

/* Features for GSO (TUNSETOFFLOAD). */

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

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