Commit 6a53fc5a authored by Akihiko Odaki's avatar Akihiko Odaki Committed by Jakub Kicinski
Browse files

tap: Use tun's vnet-related code 



tun and tap implements the same vnet-related features so reuse the code.

Signed-off-by: default avatarAkihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250207-tun-v6-7-fb49cf8b103e@daynix.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 74212f20

drivers/net/tap.c

+16 −136
Original line number Diff line number Diff line
@@ -26,74 +26,9 @@ 
#include <linux/virtio_net.h>

#include <linux/skb_array.h>



#define TAP_IFFEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)



#define TAP_VNET_LE 0x80000000

#define TAP_VNET_BE 0x40000000



#ifdef CONFIG_TUN_VNET_CROSS_LE

static inline bool tap_legacy_is_little_endian(struct tap_queue *q)

{

	return q->flags & TAP_VNET_BE ? false :

		virtio_legacy_is_little_endian();

}



static long tap_get_vnet_be(struct tap_queue *q, int __user *sp)

{

	int s = !!(q->flags & TAP_VNET_BE);



	if (put_user(s, sp))

		return -EFAULT;



	return 0;

}



static long tap_set_vnet_be(struct tap_queue *q, int __user *sp)

{

	int s;



	if (get_user(s, sp))

		return -EFAULT;



	if (s)

		q->flags |= TAP_VNET_BE;

	else

		q->flags &= ~TAP_VNET_BE;



	return 0;

}

#else

static inline bool tap_legacy_is_little_endian(struct tap_queue *q)

{

	return virtio_legacy_is_little_endian();

}



static long tap_get_vnet_be(struct tap_queue *q, int __user *argp)

{

	return -EINVAL;

}

#include "tun_vnet.h"



static long tap_set_vnet_be(struct tap_queue *q, int __user *argp)

{

	return -EINVAL;

}

#endif /* CONFIG_TUN_VNET_CROSS_LE */



static inline bool tap_is_little_endian(struct tap_queue *q)

{

	return q->flags & TAP_VNET_LE ||

		tap_legacy_is_little_endian(q);

}



static inline u16 tap16_to_cpu(struct tap_queue *q, __virtio16 val)

{

	return __virtio16_to_cpu(tap_is_little_endian(q), val);

}



static inline __virtio16 cpu_to_tap16(struct tap_queue *q, u16 val)

{

	return __cpu_to_virtio16(tap_is_little_endian(q), val);

}

#define TAP_IFFEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)



static struct proto tap_proto = {

	.name = "tap",
@@ -655,25 +590,13 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, 
	if (q->flags & IFF_VNET_HDR) {

		vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);



		err = -EINVAL;

		if (len < vnet_hdr_len)

			goto err;

		len -= vnet_hdr_len;



		err = -EFAULT;

		if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from))

		hdr_len = tun_vnet_hdr_get(vnet_hdr_len, q->flags, from, &vnet_hdr);

		if (hdr_len < 0) {

			err = hdr_len;

			goto err;

		iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));

		hdr_len = tap16_to_cpu(q, vnet_hdr.hdr_len);

		if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {

			hdr_len = max(tap16_to_cpu(q, vnet_hdr.csum_start) +

				      tap16_to_cpu(q, vnet_hdr.csum_offset) + 2,

				      hdr_len);

			vnet_hdr.hdr_len = cpu_to_tap16(q, hdr_len);

		}

		err = -EINVAL;

		if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len)

			goto err;



		len -= vnet_hdr_len;

	}



	err = -EINVAL;
@@ -725,8 +648,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, 
	skb->dev = tap->dev;



	if (vnet_hdr_len) {

		err = virtio_net_hdr_to_skb(skb, &vnet_hdr,

					    tap_is_little_endian(q));

		err = tun_vnet_hdr_to_skb(q->flags, skb, &vnet_hdr);

		if (err) {

			rcu_read_unlock();

			drop_reason = SKB_DROP_REASON_DEV_HDR;
@@ -789,23 +711,17 @@ static ssize_t tap_put_user(struct tap_queue *q, 
	int total;



	if (q->flags & IFF_VNET_HDR) {

		int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;

		struct virtio_net_hdr vnet_hdr;



		vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);

		if (iov_iter_count(iter) < vnet_hdr_len)

			return -EINVAL;



		if (virtio_net_hdr_from_skb(skb, &vnet_hdr,

					    tap_is_little_endian(q), true,

					    vlan_hlen))

			BUG();



		if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=

		    sizeof(vnet_hdr))

			return -EFAULT;

		ret = tun_vnet_hdr_from_skb(q->flags, NULL, skb, &vnet_hdr);

		if (ret)

			return ret;



		iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));

		ret = tun_vnet_hdr_put(vnet_hdr_len, iter, &vnet_hdr);

		if (ret)

			return ret;

	}

	total = vnet_hdr_len;

	total += skb->len;
@@ -1064,42 +980,6 @@ static long tap_ioctl(struct file *file, unsigned int cmd, 
		q->sk.sk_sndbuf = s;

		return 0;



	case TUNGETVNETHDRSZ:

		s = q->vnet_hdr_sz;

		if (put_user(s, sp))

			return -EFAULT;

		return 0;



	case TUNSETVNETHDRSZ:

		if (get_user(s, sp))

			return -EFAULT;

		if (s < (int)sizeof(struct virtio_net_hdr))

			return -EINVAL;



		q->vnet_hdr_sz = s;

		return 0;



	case TUNGETVNETLE:

		s = !!(q->flags & TAP_VNET_LE);

		if (put_user(s, sp))

			return -EFAULT;

		return 0;



	case TUNSETVNETLE:

		if (get_user(s, sp))

			return -EFAULT;

		if (s)

			q->flags |= TAP_VNET_LE;

		else

			q->flags &= ~TAP_VNET_LE;

		return 0;



	case TUNGETVNETBE:

		return tap_get_vnet_be(q, sp);



	case TUNSETVNETBE:

		return tap_set_vnet_be(q, sp);



	case TUNSETOFFLOAD:

		/* let the user check for future flags */

		if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
@@ -1143,7 +1023,7 @@ static long tap_ioctl(struct file *file, unsigned int cmd, 
		return ret;



	default:

		return -EINVAL;

		return tun_vnet_ioctl(&q->vnet_hdr_sz, &q->flags, cmd, sp);

	}

}
@@ -1190,7 +1070,7 @@ static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) 
	skb->protocol = eth_hdr(skb)->h_proto;



	if (vnet_hdr_len) {

		err = virtio_net_hdr_to_skb(skb, gso, tap_is_little_endian(q));

		err = tun_vnet_hdr_to_skb(q->flags, skb, gso);

		if (err)

			goto err_kfree;

	}