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* [PATCH net] net: dsa: tag_rtl4_a: Fix egress tags
@ 2021-08-28 23:56 Linus Walleij
  2021-08-30  7:29 ` Vladimir Oltean
  0 siblings, 1 reply; 10+ messages in thread
From: Linus Walleij @ 2021-08-28 23:56 UTC (permalink / raw)
  To: Andrew Lunn, Vivien Didelot, Florian Fainelli, Vladimir Oltean,
	David S . Miller, Jakub Kicinski
  Cc: netdev, Linus Walleij, DENG Qingfang, Mauri Sandberg

I noticed that only port 0 worked on the RTL8366RB since we
started to use custom tags.

It turns out that the format of egress custom tags is actually
different from ingress custom tags. While the lower bits just
contain the port number in ingress tags, egress tags need to
indicate destination port by setting the bit for the
corresponding port.

It was working on port 0 because port 0 added 0x00 as port
number in the lower bits, and if you do this the packet gets
broadcasted to all ports, including the intended port.
Ooops.

Fix this and all ports work again.

Tested on the D-Link DIR-685 by sending traffic to each of
the ports in turn. It works.

Fixes: 86dd9868b878 ("net: dsa: tag_rtl4_a: Support also egress tags")
Cc: DENG Qingfang <dqfext@gmail.com>
Cc: Mauri Sandberg <sandberg@mailfence.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 net/dsa/tag_rtl4_a.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c
index 57c46b4ab2b3..042a6cb7704a 100644
--- a/net/dsa/tag_rtl4_a.c
+++ b/net/dsa/tag_rtl4_a.c
@@ -54,9 +54,10 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
 	p = (__be16 *)tag;
 	*p = htons(RTL4_A_ETHERTYPE);
 
-	out = (RTL4_A_PROTOCOL_RTL8366RB << 12) | (2 << 8);
-	/* The lower bits is the port number */
-	out |= (u8)dp->index;
+	out = (RTL4_A_PROTOCOL_RTL8366RB << RTL4_A_PROTOCOL_SHIFT);
+	/* The lower bits indicate the port number */
+	out |= BIT(dp->index);
+
 	p = (__be16 *)(tag + 2);
 	*p = htons(out);
 
-- 
2.31.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH net] net: dsa: tag_rtl4_a: fix egress tags
@ 2021-02-28 17:08 DENG Qingfang
  2021-02-28 17:54 ` Florian Fainelli
  2021-03-01 13:58 ` Linus Walleij
  0 siblings, 2 replies; 10+ messages in thread
From: DENG Qingfang @ 2021-02-28 17:08 UTC (permalink / raw)
  To: Andrew Lunn, Vivien Didelot, Florian Fainelli, Vladimir Oltean,
	David S. Miller, Jakub Kicinski, netdev, linux-kernel
  Cc: Linus Walleij

Commit 86dd9868b878 has several issues, but was accepted too soon
before anyone could take a look.

- Double free. dsa_slave_xmit() will free the skb if the xmit function
  returns NULL, but the skb is already freed by eth_skb_pad(). Use
  __skb_put_padto() to avoid that.
- Unnecessary allocation. It has been done by DSA core since commit
  a3b0b6479700.
- A u16 pointer points to skb data. It should be __be16 for network
  byte order.
- Typo in comments. "numer" -> "number".

Fixes: 86dd9868b878 ("net: dsa: tag_rtl4_a: Support also egress tags")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
---
 net/dsa/tag_rtl4_a.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c
index c17d39b4a1a0..e9176475bac8 100644
--- a/net/dsa/tag_rtl4_a.c
+++ b/net/dsa/tag_rtl4_a.c
@@ -35,14 +35,12 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
 				      struct net_device *dev)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
+	__be16 *p;
 	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)
+	if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false)))
 		return NULL;
 
 	netdev_dbg(dev, "add realtek tag to package to port %d\n",
@@ -53,13 +51,13 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
 	tag = skb->data + 2 * ETH_ALEN;
 
 	/* Set Ethertype */
-	p = (u16 *)tag;
+	p = (__be16 *)tag;
 	*p = htons(RTL4_A_ETHERTYPE);
 
 	out = (RTL4_A_PROTOCOL_RTL8366RB << 12) | (2 << 8);
-	/* The lower bits is the port numer */
+	/* The lower bits is the port number */
 	out |= (u8)dp->index;
-	p = (u16 *)(tag + 2);
+	p = (__be16 *)(tag + 2);
 	*p = htons(out);
 
 	return skb;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2021-08-31 19:06 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-28 23:56 [PATCH net] net: dsa: tag_rtl4_a: Fix egress tags Linus Walleij
2021-08-30  7:29 ` Vladimir Oltean
2021-08-30 21:56   ` Linus Walleij
2021-08-30 22:20     ` Vladimir Oltean
2021-08-31 18:35       ` Linus Walleij
2021-08-31 19:05         ` Vladimir Oltean
  -- strict thread matches above, loose matches on Subject: below --
2021-02-28 17:08 [PATCH net] net: dsa: tag_rtl4_a: fix " DENG Qingfang
2021-02-28 17:54 ` Florian Fainelli
2021-03-01 13:58 ` Linus Walleij
2021-03-01 14:01   ` Vladimir Oltean

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