Merge branch 'net-stmmac-l3-l4-filter-bug-fixes'

Nazim Amirul says:

====================
net: stmmac: L3/L4 filter bug fixes

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").
====================

Link: https://patch.msgid.link/20260714023716.29865-1-muhammad.nazim.amirul.nazle.asmade@altera.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

2 files changed, 51 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);
 
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 +462,37 @@ 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;
 }
@@ -598,6 +630,8 @@ 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)
+			return ret;
 	}
 
 	if (!entry->in_use)
@@ -627,6 +661,7 @@ 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;
 }