Netdev Archive on
help / color / mirror / Atom feed
From: Vladimir Oltean <>
To:, Jakub Kicinski <>,
	"David S. Miller" <>
Cc: Andrew Lunn <>,
	Florian Fainelli <>,
	Vivien Didelot <>
Subject: [PATCH net 4/6] net: dsa: sja1105: ignore the FDB entry for unknown multicast when adding a new address
Date: Fri, 30 Jul 2021 20:18:13 +0300	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Currently, when sja1105pqrs_fdb_add() is called for a host-joined IPv6
MDB entry such as 33:33:00:00:00:6a, the search for that address will
return the FDB entry for SJA1105_UNKNOWN_MULTICAST, which has a
destination MAC of 01:00:00:00:00:00 and a mask of 01:00:00:00:00:00.
It returns that entry because, well, it matches, in the sense that
unknown multicast is supposed by design to match it...

But the issue is that we then proceed to overwrite this entry with the
one for our precise host-joined multicast address, and the unknown
multicast entry is no longer there - unknown multicast is now flooded to
the same group of ports as broadcast, which does not look up the FDB.

To solve this problem, we should ignore searches that return the unknown
multicast address as the match, and treat them as "no match" which will
result in the entry being installed to hardware.

For this to work properly, we need to put the result of the FDB search
in a temporary variable in order to avoid overwriting the l2_lookup
entry we want to program. The l2_lookup entry returned by the search
might not have the same set of DESTPORTS and not even the same MACADDR
as the entry we're trying to add.

Fixes: 4d9423549501 ("net: dsa: sja1105: offload bridge port flags to device")
Signed-off-by: Vladimir Oltean <>
 drivers/net/dsa/sja1105/sja1105_main.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index 5a4c7789ca43..5d8739b30d8c 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -1456,14 +1456,19 @@ int sja1105pqrs_fdb_add(struct dsa_switch *ds, int port,
 	l2_lookup.destports = BIT(port);
+	tmp = l2_lookup;
 	rc = sja1105_dynamic_config_read(priv, BLK_IDX_L2_LOOKUP,
-					 SJA1105_SEARCH, &l2_lookup);
-	if (rc == 0) {
+					 SJA1105_SEARCH, &tmp);
+	if (rc == 0 && tmp.index != SJA1105_MAX_L2_LOOKUP_COUNT - 1) {
 		/* Found a static entry and this port is already in the entry's
 		 * port mask => job done
-		if ((l2_lookup.destports & BIT(port)) && l2_lookup.lockeds)
+		if ((tmp.destports & BIT(port)) && tmp.lockeds)
 			return 0;
+		l2_lookup = tmp;
 		/* l2_lookup.index is populated by the switch in case it
 		 * found something.

  parent reply	other threads:[~2021-07-30 17:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 17:18 [PATCH net 0/6] FDB fixes for NXP SJA1105 Vladimir Oltean
2021-07-30 17:18 ` [PATCH net 1/6] net: dsa: sja1105: fix static FDB writes for SJA1110 Vladimir Oltean
2021-07-30 17:18 ` [PATCH net 2/6] net: dsa: sja1105: overwrite dynamic FDB entries with static ones in .port_fdb_add Vladimir Oltean
2021-07-30 17:18 ` [PATCH net 3/6] net: dsa: sja1105: invalidate dynamic FDB entries learned concurrently with statically added ones Vladimir Oltean
2021-07-30 17:18 ` Vladimir Oltean [this message]
2021-07-30 17:18 ` [PATCH net 5/6] net: dsa: sja1105: be stateless with FDB entries on SJA1105P/Q/R/S/SJA1110 too Vladimir Oltean
2021-07-30 17:18 ` [PATCH net 6/6] net: dsa: sja1105: match FDB entries regardless of inner/outer VLAN tag Vladimir Oltean
2021-08-02 13:30 ` [PATCH net 0/6] FDB fixes for NXP SJA1105 patchwork-bot+netdevbpf

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).