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From:   Veerendranath Jakkam <vjakkam@codeaurora.org>
To:     johannes@sipsolutions.net
Cc:     linux-wireless@vger.kernel.org
Subject: [PATCH] cfg80211: Enhance the AKM advertizement to support per interface.
Date:   Tue, 24 Dec 2019 00:22:55 +0530
Message-Id: <20191223185255.1009-1-vjakkam@codeaurora.org>
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Sender: linux-wireless-owner@vger.kernel.org
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Commit ab4dfa20534e ("cfg80211: Allow drivers to advertise supported AKM
suites") introduces the support to advertize the AKM support.

This needs an enhancement to advertize the AKM support per interface type,
specifically for the cfg80211-based drivers that implement SME and use
different mechanisms to support the AKM's for each interface type (e.g.,
the support for SAE, OWE AKM's take different paths for such drivers on
STA/AP mode).

User space would like to know if such driver has the implementation for
an AKM on a respective interface type.

This commit aims the same and replaces the earlier mechanism of advertizing
the AKM per wiphy.

User space shall assume that all AKMs for each interface type are
supported, if the driver does not advertize this capability.

Signed-off-by: Veerendranath Jakkam <vjakkam@codeaurora.org>
---
 include/net/cfg80211.h       | 20 +++++++++++++-----
 include/uapi/linux/nl80211.h |  7 ++++++
 net/wireless/nl80211.c       | 41 ++++++++++++++++++++++++++++++++----
 3 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 059524b87c4c..3e92e674a941 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4370,6 +4370,16 @@ struct cfg80211_pmsr_capabilities {
 	} ftm;
 };
 
+/**
+ * struct ieee80211_akm_suites - supported akm suites
+ * @akm_suites: points to an array of supported akm suites
+ * @n_akm_suites: number of supported AKM suites
+ */
+struct ieee80211_akm_suites {
+	const u32 *akm_suites;
+	int n_akm_suites;
+};
+
 /**
  * struct wiphy - wireless hardware description
  * @reg_notifier: the driver's regulatory notification callback,
@@ -4382,8 +4392,6 @@ struct cfg80211_pmsr_capabilities {
  * @signal_type: signal type reported in &struct cfg80211_bss.
  * @cipher_suites: supported cipher suites
  * @n_cipher_suites: number of supported cipher suites
- * @akm_suites: supported AKM suites
- * @n_akm_suites: number of supported AKM suites
  * @retry_short: Retry limit for short frames (dot11ShortRetryLimit)
  * @retry_long: Retry limit for long frames (dot11LongRetryLimit)
  * @frag_threshold: Fragmentation threshold (dot11FragmentationThreshold);
@@ -4543,6 +4551,9 @@ struct cfg80211_pmsr_capabilities {
  *	@support_mbssid must be set for this to have any effect.
  *
  * @pmsr_capa: peer measurement capabilities
+ *
+ * @supported_akm_suites: supported akm suites info per interface, points to an
+ *	array indexed by interface type
  */
 struct wiphy {
 	/* assign these fields before you register the wiphy */
@@ -4587,9 +4598,6 @@ struct wiphy {
 	int n_cipher_suites;
 	const u32 *cipher_suites;
 
-	int n_akm_suites;
-	const u32 *akm_suites;
-
 	u8 retry_short;
 	u8 retry_long;
 	u32 frag_threshold;
@@ -4687,6 +4695,8 @@ struct wiphy {
 
 	const struct cfg80211_pmsr_capabilities *pmsr_capa;
 
+	const struct ieee80211_akm_suites *supported_akm_suites;
+
 	char priv[0] __aligned(NETDEV_ALIGN);
 };
 
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 341e0e8cae46..3b11df917818 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2400,6 +2400,11 @@ enum nl80211_commands {
  * @NL80211_ATTR_VLAN_ID: VLAN ID (1..4094) for the station and VLAN group key
  *	(u16).
  *
+ * @NL80211_ATTR_SUPPORTED_AKM_SUITES: Used for AKM suite capability
+ *	advertisement per interface. This is a nested attribute of
+ *	%NL80211_ATTR_FRAME_TYPE attributes, containing the supported AKM's
+ *	per interface.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2864,6 +2869,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_VLAN_ID,
 
+	NL80211_ATTR_SUPPORTED_AKM_SUITES,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index fa3526592c51..e27f0f9e5848 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -1885,6 +1885,41 @@ static int nl80211_send_pmsr_capa(struct cfg80211_registered_device *rdev,
 	return 0;
 }
 
+static int
+nl80211_send_akm_suites(struct sk_buff *msg,
+			const struct ieee80211_akm_suites *supported_akm_suites)
+{
+	struct nlattr *nl_ftypes, *nl_ifs;
+	enum nl80211_iftype ift;
+	const struct ieee80211_akm_suites *supported_akms;
+
+	if (!supported_akm_suites)
+		return 0;
+
+	nl_ifs = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_AKM_SUITES);
+	if (!nl_ifs)
+		return -ENOBUFS;
+
+	for (ift = 0; ift < NUM_NL80211_IFTYPES; ift++) {
+		nl_ftypes = nla_nest_start(msg, ift);
+		if (!nl_ftypes)
+			return -ENOBUFS;
+
+		supported_akms = &supported_akm_suites[ift];
+		if (supported_akms->akm_suites &&
+		    nla_put(msg, NL80211_ATTR_AKM_SUITES,
+			    sizeof(u32) * supported_akms->n_akm_suites,
+			    supported_akms->akm_suites)) {
+			return -ENOBUFS;
+		}
+		nla_nest_end(msg, nl_ftypes);
+	}
+
+	nla_nest_end(msg, nl_ifs);
+
+	return 0;
+}
+
 struct nl80211_dump_wiphy_state {
 	s64 filter_wiphy;
 	long start;
@@ -2437,10 +2472,8 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		state->split_start++;
 		break;
 	case 15:
-		if (rdev->wiphy.akm_suites &&
-		    nla_put(msg, NL80211_ATTR_AKM_SUITES,
-			    sizeof(u32) * rdev->wiphy.n_akm_suites,
-			    rdev->wiphy.akm_suites))
+		if (nl80211_send_akm_suites(msg,
+					    rdev->wiphy.supported_akm_suites))
 			goto nla_put_failure;
 
 		/* done */
-- 
2.20.1