[PATCH v3 0/3] net: stmmac: L3/L4 filter bug fixes

[PATCH v3 0/3] net: stmmac: L3/L4 filter bug fixes

[muhammad.nazim.amirul.nazle.asmade]

From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>

This series fixes three bugs in the stmmac L3/L4 TC flower filter
implementation for the XGMAC2 core. All three patches target net.

The L3/L4 filter match count statistics patch (originally patch 4/4)
has been split out and will be sent separately against net-next per
Andrew Lunn's review of v1.

Patch 1 fixes a register corruption bug in the L4 filter port configuration.
The XGMAC_L4_ADDR register holds both source and destination port match
values in a single register. The original code overwrites the entire register
when setting either field, silently erasing the other. This is fixed by
using a read-modify-write sequence.

Patch 2 fixes the basic flow match parser to properly reject unsupported
offload requests with -EOPNOTSUPP instead of silently accepting them.
Unsupported cases include partial protocol masks, non-IPv4 network proto,
and non-TCP/UDP transport proto. Extack messages are now included so users
know exactly which part of the match is unsupported. The -EOPNOTSUPP is
also now returned directly instead of using break, which was silently
discarding the error on FLOW_CLS_REPLACE operations.

Patch 3 fixes a stale action bug on filter deletion. When a filter entry
with a drop action is deleted, the action field was not reset, causing
it to persist and potentially affect subsequent filter configurations.

All three patches fix the original L3/L4 filter implementation introduced in
425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower").

Changes in v3:
- Patch 2: add extack messages to each -EOPNOTSUPP return (Jakub Kicinski)
- Patch 2: return -EOPNOTSUPP directly instead of break to avoid silently
  reporting success on unsupported FLOW_CLS_REPLACE (Sashiko review)

Changes in v2:
- Split patch 4/4 (ethtool stats) out to net-next per Andrew Lunn's review

Nazim Amirul (3):
  net: stmmac: xgmac: fix l4 filter port overwrite on register update
  net: stmmac: fix l3l4 filter rejecting unsupported offload requests
  net: stmmac: reset residual action in L3L4 filters on delete

 .../ethernet/stmicro/stmmac/dwxgmac2_core.c   | 28 +++++++++++--------
 .../net/ethernet/stmicro/stmmac/stmmac_tc.c   | 35 +++++++++++++++++++
 2 files changed, 49 insertions(+), 12 deletions(-)

-- 
2.43.7

[PATCH v2 1/3] net: stmmac: xgmac: fix l4 filter port overwrite on register update

[muhammad.nazim.amirul.nazle.asmade]

From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>

The XGMAC_L4_ADDR register holds both source and destination port
match values. The current implementation overwrites the entire register
when configuring either port, so setting one silently erases the other.

Fix this by reading the register first, then masking and updating only
the relevant field before writing back.

Fixes: 425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower")
Signed-off-by: Rohan G Thomas <rohan.g.thomas@altera.com>
Signed-off-by: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
---
 .../ethernet/stmicro/stmmac/dwxgmac2_core.c   | 28 +++++++++++--------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index f02b434bbd50..52054f31376d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -1370,36 +1370,40 @@ static int dwxgmac2_config_l4_filter(struct mac_device_info *hw, u32 filter_no,
 		value &= ~XGMAC_L4PEN0;
 	}
 
-	value &= ~(XGMAC_L4SPM0 | XGMAC_L4SPIM0);
-	value &= ~(XGMAC_L4DPM0 | XGMAC_L4DPIM0);
 	if (sa) {
 		value |= XGMAC_L4SPM0;
 		if (inv)
 			value |= XGMAC_L4SPIM0;
+		else
+			value &= ~XGMAC_L4SPIM0;
 	} else {
 		value |= XGMAC_L4DPM0;
 		if (inv)
 			value |= XGMAC_L4DPIM0;
+		else
+			value &= ~XGMAC_L4DPIM0;
 	}
 
 	ret = dwxgmac2_filter_write(hw, filter_no, XGMAC_L3L4_CTRL, value);
 	if (ret)
 		return ret;
 
-	if (sa) {
-		value = FIELD_PREP(XGMAC_L4SP0, match);
+	ret = dwxgmac2_filter_read(hw, filter_no, XGMAC_L4_ADDR, &value);
+	if (ret)
+		return ret;
 
-		ret = dwxgmac2_filter_write(hw, filter_no, XGMAC_L4_ADDR, value);
-		if (ret)
-			return ret;
+	if (sa) {
+		value &= ~XGMAC_L4SP0;
+		value |= FIELD_PREP(XGMAC_L4SP0, match);
 	} else {
-		value = FIELD_PREP(XGMAC_L4DP0, match);
-
-		ret = dwxgmac2_filter_write(hw, filter_no, XGMAC_L4_ADDR, value);
-		if (ret)
-			return ret;
+		value &= ~XGMAC_L4DP0;
+		value |= FIELD_PREP(XGMAC_L4DP0, match);
 	}
 
+	ret = dwxgmac2_filter_write(hw, filter_no, XGMAC_L4_ADDR, value);
+	if (ret)
+		return ret;
+
 	if (!en)
 		return dwxgmac2_filter_write(hw, filter_no, XGMAC_L3L4_CTRL, 0);
 
-- 
2.43.7

[PATCH v3 2/3] net: stmmac: fix l3l4 filter rejecting unsupported offload requests

[muhammad.nazim.amirul.nazle.asmade]

From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>

The basic flow parser in tc_add_basic_flow() does not validate match
keys before proceeding. Unsupported offload configurations such as
partial protocol masks, non-IPv4 network proto, or non-TCP/UDP transport
proto are silently accepted instead of returning -EOPNOTSUPP.

Add validation to return -EOPNOTSUPP early for:
- No network or transport proto present in the key
- Partial protocol mask (only full mask supported)
- Network proto is not IPv4
- Transport proto is not TCP or UDP

Each rejection includes an extack message so the user knows which part
of the match is unsupported.

Also propagate -EOPNOTSUPP from tc_add_basic_flow() in tc_add_flow()
by returning it directly rather than using break. The break was silently
discarding the error for FLOW_CLS_REPLACE operations where entry->in_use
is already true, causing tc_add_flow() to return 0 (success) for
unsupported replace requests.

Fixes: 425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower")
Signed-off-by: Rohan G Thomas <rohan.g.thomas@altera.com>
Signed-off-by: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
---
Changes in v3:
- Add extack messages to each -EOPNOTSUPP return so users know which
  part of the match is unsupported (Jakub Kicinski)
- Return -EOPNOTSUPP directly instead of break to avoid silently
  reporting success on unsupported FLOW_CLS_REPLACE (Sashiko review)
- Patches 1/3 and 3/3 are unchanged from v2

Changes in v2:
- No changes

---
 .../net/ethernet/stmicro/stmmac/stmmac_tc.c   | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index d78652718599..14cabe76e53e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -446,6 +446,7 @@ static int tc_parse_flow_actions(struct stmmac_priv *priv,
 }
 
 #define ETHER_TYPE_FULL_MASK	cpu_to_be16(~0)
+#define IP_PROTO_FULL_MASK	0xFF
 
 static int tc_add_basic_flow(struct stmmac_priv *priv,
 			     struct flow_cls_offload *cls,
@@ -461,6 +462,33 @@ static int tc_add_basic_flow(struct stmmac_priv *priv,
 
 	flow_rule_match_basic(rule, &match);
 
+	/* Both network proto and transport proto not present in the key */
+	if (!match.mask || !(match.mask->n_proto || match.mask->ip_proto)) {
+		NL_SET_ERR_MSG_MOD(cls->common.extack,
+				   "filter must specify network or transport protocol");
+		return -EOPNOTSUPP;
+	}
+
+	/* If the proto is present in the key and is not full mask */
+	if ((match.mask->n_proto && match.mask->n_proto != ETHER_TYPE_FULL_MASK) ||
+	    (match.mask->ip_proto && match.mask->ip_proto != IP_PROTO_FULL_MASK)) {
+		NL_SET_ERR_MSG_MOD(cls->common.extack,
+				   "only full protocol mask is supported");
+		return -EOPNOTSUPP;
+	}
+
+	/* Network proto is present in the key and is not IPv4 */
+	if (match.mask->n_proto && match.key->n_proto != cpu_to_be16(ETH_P_IP)) {
+		NL_SET_ERR_MSG_MOD(cls->common.extack,
+				   "only IPv4 network protocol is supported");
+		return -EOPNOTSUPP;
+	}
+
+	/* Transport proto is present in the key and is not TCP or UDP */
+	if (match.mask->ip_proto &&
+	    match.key->ip_proto != IPPROTO_TCP &&
+	    match.key->ip_proto != IPPROTO_UDP) {
+		NL_SET_ERR_MSG_MOD(cls->common.extack,
+				   "only TCP and UDP transport protocols are supported");
+		return -EOPNOTSUPP;
+	}
+
 	entry->ip_proto = match.key->ip_proto;
 	return 0;
 }
@@ -598,11 +626,7 @@ static int tc_add_flow(struct stmmac_priv *priv,
 		ret = tc_flow_parsers[i].fn(priv, cls, entry);
 		if (!ret)
 			entry->in_use = true;
-		else if (ret == -EOPNOTSUPP)
-			/* The basic flow parser will return EOPNOTSUPP, if a
-			 * requested offload not fully supported by the hw. And
-			 * in that case fail early.
-			 */
-			break;
+		else if (ret == -EOPNOTSUPP)
+			return ret;
 	}
 
 	if (!entry->in_use)
-- 
2.43.7

[PATCH v2 3/3] net: stmmac: reset residual action in L3L4 filters on delete

[muhammad.nazim.amirul.nazle.asmade]

From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>

When deleting an L3/L4 flower filter entry, the action field is not
reset. If a filter was previously configured with a drop action, that
action may persist and affect subsequent filter configurations
unintentionally.

Clear the action field when the filter entry is deleted.

Fixes: 425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower")
Signed-off-by: Rohan G Thomas <rohan.g.thomas@altera.com>
Signed-off-by: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 869f84756ca5..4f9758eeb86f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -653,6 +653,7 @@ static int tc_del_flow(struct stmmac_priv *priv,
 	entry->in_use = false;
 	entry->cookie = 0;
 	entry->is_l4 = false;
+	entry->action = 0;
 	return ret;
 }
 
-- 
2.43.7

Re: [PATCH v3 0/3] net: stmmac: L3/L4 filter bug fixes

[Maxime Chevallier]

Hi Nazim,

On 6/16/26 06:26, muhammad.nazim.amirul.nazle.asmade@altera.com wrote:
> From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
> 
> This series fixes three bugs in the stmmac L3/L4 TC flower filter
> implementation for the XGMAC2 core. All three patches target net.
> 
> The L3/L4 filter match count statistics patch (originally patch 4/4)
> has been split out and will be sent separately against net-next per
> Andrew Lunn's review of v1.
> 
> Patch 1 fixes a register corruption bug in the L4 filter port configuration.
> The XGMAC_L4_ADDR register holds both source and destination port match
> values in a single register. The original code overwrites the entire register
> when setting either field, silently erasing the other. This is fixed by
> using a read-modify-write sequence.
> 
> Patch 2 fixes the basic flow match parser to properly reject unsupported
> offload requests with -EOPNOTSUPP instead of silently accepting them.
> Unsupported cases include partial protocol masks, non-IPv4 network proto,
> and non-TCP/UDP transport proto. Extack messages are now included so users
> know exactly which part of the match is unsupported. The -EOPNOTSUPP is
> also now returned directly instead of using break, which was silently
> discarding the error on FLOW_CLS_REPLACE operations.
> 
> Patch 3 fixes a stale action bug on filter deletion. When a filter entry
> with a drop action is deleted, the action field was not reset, causing
> it to persist and potentially affect subsequent filter configurations.
> 
> All three patches fix the original L3/L4 filter implementation introduced in
> 425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower").
> 
> Changes in v3:
> - Patch 2: add extack messages to each -EOPNOTSUPP return (Jakub Kicinski)
> - Patch 2: return -EOPNOTSUPP directly instead of break to avoid silently
>   reporting success on unsupported FLOW_CLS_REPLACE (Sashiko review)

Please take a look at this page prior to reposting :

https://netdev.bots.linux.dev/net-next.html

There's also an announcement made on the netdev@ list when net-next
opens/closes.

You can't submit new series that target net-next during the merge window,
this revision will have to wait 2 weeks.

Maxime

Re: [PATCH v3 0/3] net: stmmac: L3/L4 filter bug fixes

[Nazle Asmade, Muhammad Nazim Amirul]

On 16/6/2026 2:06 pm, Maxime Chevallier wrote:
> Hi Nazim,
>
> On 6/16/26 06:26, muhammad.nazim.amirul.nazle.asmade@altera.com wrote:
>> From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
>>
>> This series fixes three bugs in the stmmac L3/L4 TC flower filter
>> implementation for the XGMAC2 core. All three patches target net.
>>
>> The L3/L4 filter match count statistics patch (originally patch 4/4)
>> has been split out and will be sent separately against net-next per
>> Andrew Lunn's review of v1.
>>
>> Patch 1 fixes a register corruption bug in the L4 filter port configuration.
>> The XGMAC_L4_ADDR register holds both source and destination port match
>> values in a single register. The original code overwrites the entire register
>> when setting either field, silently erasing the other. This is fixed by
>> using a read-modify-write sequence.
>>
>> Patch 2 fixes the basic flow match parser to properly reject unsupported
>> offload requests with -EOPNOTSUPP instead of silently accepting them.
>> Unsupported cases include partial protocol masks, non-IPv4 network proto,
>> and non-TCP/UDP transport proto. Extack messages are now included so users
>> know exactly which part of the match is unsupported. The -EOPNOTSUPP is
>> also now returned directly instead of using break, which was silently
>> discarding the error on FLOW_CLS_REPLACE operations.
>>
>> Patch 3 fixes a stale action bug on filter deletion. When a filter entry
>> with a drop action is deleted, the action field was not reset, causing
>> it to persist and potentially affect subsequent filter configurations.
>>
>> All three patches fix the original L3/L4 filter implementation introduced in
>> 425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower").
>>
>> Changes in v3:
>> - Patch 2: add extack messages to each -EOPNOTSUPP return (Jakub Kicinski)
>> - Patch 2: return -EOPNOTSUPP directly instead of break to avoid silently
>>    reporting success on unsupported FLOW_CLS_REPLACE (Sashiko review)
>
> Please take a look at this page prior to reposting :
>
> https://netdev.bots.linux.dev/net-next.html
>
> There's also an announcement made on the netdev@ list when net-next
> opens/closes.
>
> You can't submit new series that target net-next during the merge window,
> this revision will have to wait 2 weeks.
>
> Maxime
>
Ah I see, Thanks Maxime :)