To avoid unexpected IOT issues, only enable EMLSR for APs that advertise
a vendor IE whose OUI is on an allowlist. The emlsr_ap_gating and
emlsr_oui module parameters disable or extend it.

Signed-off-by: Emery Hsin <emery.hsin@mediatek.com>
---
 .../net/wireless/mediatek/mt76/mt7925/mcu.c   | 76 ++++++++++++++++++-
 1 file changed, 75 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
index 1d59c02645c6..8323c821d4d8 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
@@ -20,6 +20,75 @@ static bool mt7925_vif_is_nan(struct ieee80211_vif *vif)
 	       vif->type == NL80211_IFTYPE_NAN_DATA;
 }
 
+/* Only APs advertising a vendor IE with one of these OUIs may use EMLSR. */
+static bool mt7925_emlsr_ap_gating = true;
+module_param_named(emlsr_ap_gating, mt7925_emlsr_ap_gating, bool, 0644);
+MODULE_PARM_DESC(emlsr_ap_gating,
+		 "gate EMLSR by the AP OUI allowlist (default on; set 0 to allow all)");
+
+static u32 mt7925_emlsr_oui_allowlist_extra[8];
+static unsigned int mt7925_emlsr_oui_num;
+module_param_array_named(emlsr_oui, mt7925_emlsr_oui_allowlist_extra, uint,
+			 &mt7925_emlsr_oui_num, 0644);
+MODULE_PARM_DESC(emlsr_oui,
+		 "extra EMLSR-permitted AP OUIs, e.g. 0x000ce7,0x00037f");
+
+static const u32 mt7925_emlsr_oui_allowlist_default[] = {
+	0x000ce7, 0x000a00, 0x0017a5, 0x000c43, 0x00620b, 0x5c6f69,
+	0xbc97e1, 0x001be9, 0x0005b5, 0x8c8474, 0x1423f3, 0x405b7f,
+	0xd404e6, 0xe03e44, 0x6c92cf, 0x043201, 0x70b7e4, 0x1423f2,
+	0x4857d2, 0x9c2183, 0x84160c, 0xe43d1a, 0x000db6, 0x000af7,
+	0xd40129, 0x6c8375, 0xb02628, 0x001018, 0x18c086, 0x38bab0,
+};
+
+static bool mt7925_emlsr_oui_match(const struct cfg80211_bss_ies *ies,
+				   const u32 *oui, unsigned int num)
+{
+	unsigned int i;
+
+	/* oui_type -1 matches any vendor-specific type */
+	for (i = 0; i < num; i++) {
+		if (cfg80211_find_vendor_ie(oui[i], -1, ies->data, ies->len))
+			return true;
+	}
+
+	return false;
+}
+
+/* Return true if EMLSR is permitted for the associated AP. */
+static bool mt7925_emlsr_oui_allowed(struct wiphy *wiphy,
+				     struct ieee80211_channel *chan,
+				     const u8 *bssid)
+{
+	const struct cfg80211_bss_ies *ies;
+	struct cfg80211_bss *bss;
+	bool allowed = false;
+
+	if (!mt7925_emlsr_ap_gating)
+		return true;
+
+	/* a NULL chan matches the BSS on any channel */
+	bss = cfg80211_get_bss(wiphy, chan, bssid, NULL, 0,
+			       IEEE80211_BSS_TYPE_ESS, IEEE80211_PRIVACY_ANY);
+	if (!bss)
+		return false;
+
+	rcu_read_lock();
+	ies = rcu_dereference(bss->beacon_ies);
+	if (!ies)
+		ies = rcu_dereference(bss->ies);
+	if (ies)
+		allowed = mt7925_emlsr_oui_match(ies, mt7925_emlsr_oui_allowlist_default,
+						 ARRAY_SIZE(mt7925_emlsr_oui_allowlist_default)) ||
+			  mt7925_emlsr_oui_match(ies, mt7925_emlsr_oui_allowlist_extra,
+						 mt7925_emlsr_oui_num);
+	rcu_read_unlock();
+
+	cfg80211_put_bss(wiphy, bss);
+
+	return allowed;
+}
+
 int mt7925_mcu_parse_response(struct mt76_dev *mdev, int cmd,
 			      struct sk_buff *skb, int seq)
 {
@@ -3056,6 +3125,7 @@ mt7925_mcu_bss_mld_tlv(struct sk_buff *skb,
 	struct bss_mld_tlv *mld;
 	struct tlv *tlv;
 	bool is_mld;
+	bool is_supported_ap = false;
 
 	is_mld = ieee80211_vif_is_mld(link_conf->vif) ||
 		 (hweight16(mvif->valid_links) > 1);
@@ -3070,8 +3140,12 @@ mt7925_mcu_bss_mld_tlv(struct sk_buff *skb,
 	mld->remap_idx = 0xff;
 
 	if (phy->chip_cap & BIT(MT792x_CHIP_CAP_MLO_EML_EN)) {
+		is_supported_ap = mt7925_emlsr_oui_allowed(phy->mt76->hw->wiphy,
+							   link_conf->chanreq.oper.chan,
+							   link_conf->bssid);
 		mld->eml_enable = !!(link_conf->vif->cfg.eml_cap &
-				     IEEE80211_EML_CAP_EMLSR_SUPP);
+				     IEEE80211_EML_CAP_EMLSR_SUPP) &&
+				  is_supported_ap;
 	} else {
 		mld->eml_enable = 0;
 	}
-- 
2.45.2