From: Linus Walleij <linus.walleij@xxxxxxxxxx>
commit 86dd9868b8788a9063893a97649594af93cd5aa6 upstream.
Support also transmitting frames using the custom "8899 A"
4 byte tag.
Qingfang came up with the solution: we need to pad the
ethernet frame to 60 bytes using eth_skb_pad(), then the
switch will happily accept frames with custom tags.
Cc: Mauri Sandberg <sandberg@xxxxxxxxxxxxx>
Reported-by: DENG Qingfang <dqfext@xxxxxxxxx>
Fixes: efd7fe68f0c6 ("net: dsa: tag_rtl4_a: Implement Realtek 4 byte A tag")
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/dsa/tag_rtl4_a.c | 43 +++++++++++++++++++++++++++++--------------
1 file changed, 29 insertions(+), 14 deletions(-)
--- a/net/dsa/tag_rtl4_a.c
+++ b/net/dsa/tag_rtl4_a.c
@@ -12,9 +12,7 @@
*
* The 2 bytes tag form a 16 bit big endian word. The exact
* meaning has been guessed from packet dumps from ingress
- * frames, as no working egress traffic has been available
- * we do not know the format of the egress tags or if they
- * are even supported.
+ * frames.
*/
#include <linux/etherdevice.h>
@@ -36,17 +34,34 @@
static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
struct net_device *dev)
{
- /*
- * Just let it pass thru, we don't know if it is possible
- * to tag a frame with the 0x8899 ethertype and direct it
- * to a specific port, all attempts at reverse-engineering have
- * ended up with the frames getting dropped.
- *
- * The VLAN set-up needs to restrict the frames to the right port.
- *
- * If you have documentation on the tagging format for RTL8366RB
- * (tag type A) then please contribute.
- */
+ struct dsa_port *dp = dsa_slave_to_port(dev);
+ u8 *tag;
+ u16 *p;
+ u16 out;
+
+ /* Pad out to at least 60 bytes */
+ if (unlikely(eth_skb_pad(skb)))
+ return NULL;
+ if (skb_cow_head(skb, RTL4_A_HDR_LEN) < 0)
+ return NULL;
+
+ netdev_dbg(dev, "add realtek tag to package to port %d\n",
+ dp->index);
+ skb_push(skb, RTL4_A_HDR_LEN);
+
+ memmove(skb->data, skb->data + RTL4_A_HDR_LEN, 2 * ETH_ALEN);
+ tag = skb->data + 2 * ETH_ALEN;
+
+ /* Set Ethertype */
+ p = (u16 *)tag;
+ *p = htons(RTL4_A_ETHERTYPE);
+
+ out = (RTL4_A_PROTOCOL_RTL8366RB << 12) | (2 << 8);
+ /* The lower bits is the port numer */
+ out |= (u8)dp->index;
+ p = (u16 *)(tag + 2);
+ *p = htons(out);
+
return skb;
}
