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Commit e6fd07c8 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

tun: unbreak truncated packet signalling 



Commit 6680ec68
(tuntap: hardware vlan tx support) breaks the truncated packet signal by nev
return a length greater than iov length in tun_put_user(). This patch fixes
by always return the length of packet plus possible vlan header. Caller can
detect the truncated packet by comparing the return value and the size of io
length.

Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1598f7cb

drivers/net/tun.c

+9 −7
Original line number Diff line number Diff line
@@ -1184,7 +1184,7 @@ static ssize_t tun_put_user(struct tun_struct *tun, 
{

	struct tun_pi pi = { 0, skb->protocol };

	ssize_t total = 0;

	int vlan_offset = 0;

	int vlan_offset = 0, copied;



	if (!(tun->flags & TUN_NO_PI)) {

		if ((len -= sizeof(pi)) < 0)
@@ -1248,6 +1248,8 @@ static ssize_t tun_put_user(struct tun_struct *tun, 
		total += tun->vnet_hdr_sz;

	}



	copied = total;

	total += skb->len;

	if (!vlan_tx_tag_present(skb)) {

		len = min_t(int, skb->len, len);

	} else {
@@ -1262,24 +1264,24 @@ static ssize_t tun_put_user(struct tun_struct *tun, 


		vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);

		len = min_t(int, skb->len + VLAN_HLEN, len);

		total += VLAN_HLEN;



		copy = min_t(int, vlan_offset, len);

		ret = skb_copy_datagram_const_iovec(skb, 0, iv, total, copy);

		ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);

		len -= copy;

		total += copy;

		copied += copy;

		if (ret || !len)

			goto done;



		copy = min_t(int, sizeof(veth), len);

		ret = memcpy_toiovecend(iv, (void *)&veth, total, copy);

		ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);

		len -= copy;

		total += copy;

		copied += copy;

		if (ret || !len)

			goto done;

	}



	skb_copy_datagram_const_iovec(skb, vlan_offset, iv, total, len);

	total += len;

	skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);



done:

	tun->dev->stats.tx_packets++;