[PATCH RESEND wireless-next 03/18] wifi: nl80211: Add kernel interfaces for Seamless Mobility Domain setup

[Pooventhiran G]

From: Aditya Sathish <asathish@xxxxxxxxxxxxxxxx>

An AP MLD managed by an SMD-ME must advertise its SMD parameters in
Beacon and Probe Response frames so that an SMD-capable non-AP MLD can
negotiate SMD during association and may choose to later perform SMD BSS
Transition. Add nl80211 kernel interfaces for userspace to configure
these parameters in nl80211_start_ap() so that the driver and lower
layers can be configured with appropriate parameters.

Signed-off-by: Aditya Sathish <asathish@xxxxxxxxxxxxxxxx>
Co-developed-by: Rohan Dutta <drohan@xxxxxxxxxxxxxxxx>
Signed-off-by: Rohan Dutta <drohan@xxxxxxxxxxxxxxxx>
Signed-off-by: Pooventhiran G <pooventhiran.g@xxxxxxxxxxxxxxxx>
---
 include/linux/ieee80211-uhr.h |  4 ++
 include/uapi/linux/nl80211.h  | 95 +++++++++++++++++++++++++++++++++++++++++++
 net/wireless/nl80211.c        | 17 ++++++++
 3 files changed, 116 insertions(+)

diff --git a/include/linux/ieee80211-uhr.h b/include/linux/ieee80211-uhr.h
index 19e9260d0db8..c3f87d4c8bec 100644
--- a/include/linux/ieee80211-uhr.h
+++ b/include/linux/ieee80211-uhr.h
@@ -589,6 +589,10 @@ ieee80211_uhr_dbe_cap(const struct ieee80211_uhr_cap *cap)
 #define IEEE80211_SMD_INFO_CAPA_TYPE			0x10
 #define IEEE80211_SMD_INFO_CAPA_PTK_PER_AP_MLD		0x20
 
+/* IEEE P802.11bn/D2.0, Aug 2026, subclause 9.4.2.363 */
+#define IEEE80211_SMD_INFO_PREP_TIMEOUT_MIN		2 /* in 64 TUs */
+#define IEEE80211_SMD_INFO_NUM_PREP_AP_MAX		7
+
 struct ieee80211_smd_info {
 	u8 id[ETH_ALEN];
 	u8 capa;
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index d9ce185b0ef1..f5c8dbe5f26a 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -3185,6 +3185,12 @@ enum nl80211_commands {
  *	The aggregated message always precedes the per-link messages for the
  *	same station within a dump sequence.
  *
+ * @NL80211_ATTR_SMD_PARAMS: Nested attribute to indicate support for Seamless
+ *	Mobility Domain (SMD); it contains parameters to define capabilities of
+ *	an AP managed by an SMD-ME. Valid if the driver supports
+ *	%NL80211_EXT_FEATURE_SMD.
+ *	Used with %NL80211_CMD_START_AP. See &enum nl80211_smd_params_attrs.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3785,6 +3791,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_STA_DUMP_LINK_STATS,
 
+	NL80211_ATTR_SMD_PARAMS,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -9118,4 +9126,91 @@ enum nl80211_nan_peer_map_attrs {
 
 #define NL80211_NAN_SCHED_NOT_AVAIL_SLOT 0xff
 
+/**
+ * enum nl80211_smd_type - Type of the SMD
+ *
+ * @NL80211_SMD_TYPE_PER_AP_MLD_MAC_SAP: Separate MAC SAP is used per AP MLD.
+ * @NL80211_SMD_TYPE_PER_SMD_MAC_SAP: one MAC SAP is used in the SMD.
+ * @NUM_NL80211_SMD_TYPES: internal.
+ * @NL80211_SMD_TYPE_MAX: Max type of the SMD.
+ *
+ * This value represents the data path models between the non-AP MLD and DS.
+ * DS mapping for the non-AP MLD is updated if
+ * %NL80211_SMD_TYPE_PER_AP_MLD_MAC_SAP is used.
+ *
+ * All AP MLDs within an SMD shall indicate the same SMD type (refer
+ * IEEE P802.11bn/D2.0, Aug 2026, subclause 37.16.1.2).
+ */
+enum nl80211_smd_type {
+	NL80211_SMD_TYPE_PER_AP_MLD_MAC_SAP,
+	NL80211_SMD_TYPE_PER_SMD_MAC_SAP,
+
+	NUM_NL80211_SMD_TYPES,
+	NL80211_SMD_TYPE_MAX = NUM_NL80211_SMD_TYPES - 1,
+};
+
+/**
+ * enum nl80211_smd_ptk_mode - PTK Mode used in the SMD
+ *
+ * @NL80211_SMD_PTK_MODE_PER_SMD_PTK: one PTK is used by all AP MLDs in the SMD.
+ * @NL80211_SMD_PTK_MODE_PER_AP_MLD_PTK: Separate PTK is used per AP MLD.
+ * @NUM_NL80211_SMD_PTK_MODES: internal.
+ * @NL80211_SMD_PTK_MODE_MAX: Max type of PTK mode.
+ *
+ * This value represents the security mode of the SMD that dictates the PTK used
+ * in current and target AP MLDs to protect communications with the non-AP MLD
+ * (refer IEEE P802.11bn/D2.0, Aug 2026, subclause 37.16.1.3.2)
+ */
+enum nl80211_smd_ptk_mode {
+	NL80211_SMD_PTK_MODE_PER_SMD_PTK,
+	NL80211_SMD_PTK_MODE_PER_AP_MLD_PTK,
+
+	NUM_NL80211_SMD_PTK_MODES,
+	NL80211_SMD_PTK_MODE_MAX = NUM_NL80211_SMD_PTK_MODES - 1,
+};
+
+/**
+ * enum nl80211_smd_params_attrs - SMD Domain parameters
+ *
+ * @NL80211_SMD_PARAMS_ATTR_UNSPEC: Invalid attribute.
+ * @NL80211_SMD_PARAMS_ATTR_IDENTIFIER: Required (binary) attribute of ETH_ALEN
+ *	bytes used to define the unique identifier for the SMD.
+ * @NL80211_SMD_PARAMS_ATTR_TIMEOUT: Required (u16) attribute to define the SMD
+ *	Preparation timeout (in 64 TUs, values 0 and 1 are reserved) for
+ *	the target AP MLD.
+ * @NL80211_SMD_PARAMS_ATTR_DL_DATA_FORWARDING: Flag attribute to indicate that
+ *	the device supports forwarding of buffered DL data packets.
+ * @NL80211_SMD_PARAMS_ATTR_MAX_PEER_APMLDS: Required (u8) attribute to define
+ *	the maximum number of AP MLDs a non-AP MLD can prepare with. Value is
+ *	the maximum number of AP MLDs - 1. A value of 0 means that the non-AP
+ *	MLD can prepare with 1 AP MLD.
+ * @NL80211_SMD_PARAMS_ATTR_TYPE: Required (u8) attribute to indicate the
+ *	SMD Type (&enum nl80211_smd_type).
+ * @NL80211_SMD_PARAMS_ATTR_PTK_MODE: Required (u8) attribute to indicate the
+ *	PTK mode used for protection (&enum nl80211_smd_ptk_mode).
+ * @NL80211_SMD_PARAMS_ATTR_NEIGHBOR_PROBING: Flag attribute to indicate that
+ *	the device supports UHR Neighboring AP Probing.
+ * @__NL80211_SMD_PARAMS_ATTR_LAST: Last attribute, used internally.
+ * @NL80211_SMD_PARAMS_ATTR_MAX: Max attribute.
+ *
+ * Nested attributes carried in %NL80211_ATTR_SMD_PARAMS to define
+ * device capabilities that is part of an SMD (refer IEEE P802.11bn/D2.0,
+ * Aug 2026, subclause 9.4.2.363, Figure 9-aa43 and Figure 9-aa44).
+ *
+ */
+enum nl80211_smd_params_attrs {
+	NL80211_SMD_PARAMS_ATTR_UNSPEC,
+	NL80211_SMD_PARAMS_ATTR_IDENTIFIER,
+	NL80211_SMD_PARAMS_ATTR_TIMEOUT,
+	NL80211_SMD_PARAMS_ATTR_DL_DATA_FORWARDING,
+	NL80211_SMD_PARAMS_ATTR_MAX_PEER_APMLDS,
+	NL80211_SMD_PARAMS_ATTR_TYPE,
+	NL80211_SMD_PARAMS_ATTR_PTK_MODE,
+	NL80211_SMD_PARAMS_ATTR_NEIGHBOR_PROBING,
+
+	/* keep last */
+	__NL80211_SMD_PARAMS_ATTR_LAST,
+	NL80211_SMD_PARAMS_ATTR_MAX = __NL80211_SMD_PARAMS_ATTR_LAST - 1
+};
+
 #endif /* __LINUX_NL80211_H */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index e585da1d79c9..22d71f32815f 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -689,6 +689,21 @@ nl80211_nan_conf_policy[NL80211_NAN_CONF_ATTR_MAX + 1] = {
 	[NL80211_NAN_CONF_NOTIFY_DW] = { .type = NLA_FLAG },
 };
 
+static const struct nla_policy
+nl80211_smd_params_policy[NL80211_SMD_PARAMS_ATTR_MAX + 1] = {
+	[NL80211_SMD_PARAMS_ATTR_IDENTIFIER] = NLA_POLICY_ETH_ADDR,
+	[NL80211_SMD_PARAMS_ATTR_TIMEOUT] =
+		NLA_POLICY_MIN(NLA_U16, IEEE80211_SMD_INFO_PREP_TIMEOUT_MIN),
+	[NL80211_SMD_PARAMS_ATTR_DL_DATA_FORWARDING] = { .type = NLA_FLAG },
+	[NL80211_SMD_PARAMS_ATTR_MAX_PEER_APMLDS] =
+		NLA_POLICY_MAX(NLA_U8, IEEE80211_SMD_INFO_NUM_PREP_AP_MAX),
+	[NL80211_SMD_PARAMS_ATTR_TYPE] =
+		NLA_POLICY_MAX(NLA_U8, NL80211_SMD_TYPE_MAX),
+	[NL80211_SMD_PARAMS_ATTR_PTK_MODE] =
+		NLA_POLICY_MAX(NLA_U8, NL80211_SMD_PTK_MODE_MAX),
+	[NL80211_SMD_PARAMS_ATTR_NEIGHBOR_PROBING] = { .type = NLA_FLAG },
+};
+
 static const struct netlink_range_validation nl80211_punct_bitmap_range = {
 	.min = 0,
 	.max = 0xffff,
@@ -1097,6 +1112,8 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_NPCA_PUNCT_BITMAP] =
 		NLA_POLICY_FULL_RANGE(NLA_U32, &nl80211_punct_bitmap_range),
 	[NL80211_ATTR_STA_DUMP_LINK_STATS] = { .type = NLA_FLAG },
+	[NL80211_ATTR_SMD_PARAMS] =
+		NLA_POLICY_NESTED(nl80211_smd_params_policy),
 };
 
 /* policy for the key attributes */

-- 
2.34.1