tun: Fix csum_start with VLAN acceleration
When VLAN acceleration is in use on the xmit path, we end up
setting csum_start to the wrong place. The result is that the
whoever ends up doing the checksum setting will corrupt the packet
instead of writing the checksum to the expected location, usually
this means writing the checksum with an offset of -4.
This patch fixes this by adjusting csum_start when VLAN acceleration
is detected.
Fixes: 6680ec68eff4 ("tuntap: hardware vlan tx support")
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 7302398..57e6bf7 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1235,6 +1235,10 @@
struct tun_pi pi = { 0, skb->protocol };
ssize_t total = 0;
int vlan_offset = 0, copied;
+ int vlan_hlen = 0;
+
+ if (vlan_tx_tag_present(skb))
+ vlan_hlen = VLAN_HLEN;
if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) < 0)
@@ -1284,7 +1288,8 @@
if (skb->ip_summed == CHECKSUM_PARTIAL) {
gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
- gso.csum_start = skb_checksum_start_offset(skb);
+ gso.csum_start = skb_checksum_start_offset(skb) +
+ vlan_hlen;
gso.csum_offset = skb->csum_offset;
} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
@@ -1297,10 +1302,9 @@
}
copied = total;
- total += skb->len;
- if (!vlan_tx_tag_present(skb)) {
- len = min_t(int, skb->len, len);
- } else {
+ len = min_t(int, skb->len + vlan_hlen, len);
+ total += skb->len + vlan_hlen;
+ if (vlan_hlen) {
int copy, ret;
struct {
__be16 h_vlan_proto;
@@ -1311,8 +1315,6 @@
veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
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, copied, copy);