brcmfmac: support 4-way handshake offloading for WPA/WPA2-PSK in AP mode

Firmware may have authenticator code built-in. This is detected by the
driver and indicated in the wiphy features flags. User space can use
this flag to determine whether or not to provide the pre-shared key
material in the nl80211 start AP command to offload the 4-way handshake
in AP mode.
Signed-off-by: Chung-Hsien Hsu <stanley.hsu@cypress.com>
Signed-off-by: Chi-Hsien Lin <chi-hsien.lin@cypress.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200817073316.33402-3-stanley.hsu@cypress.com

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c

@@ -4679,6 +4679,8 @@ brcmf_cfg80211_start_ap(struct wiphy *wiphy, struct net_device *ndev,
 	struct brcmf_cfg80211_info *cfg = wiphy_to_cfg(wiphy);
 	struct brcmf_if *ifp = netdev_priv(ndev);
 	struct brcmf_pub *drvr = cfg->pub;
+	struct brcmf_cfg80211_profile *profile = &ifp->vif->profile;
+	struct cfg80211_crypto_settings *crypto = &settings->crypto;
 	const struct brcmf_tlv *ssid_ie;
 	const struct brcmf_tlv *country_ie;
 	struct brcmf_ssid_le ssid_le;
@@ -4818,6 +4820,17 @@ brcmf_cfg80211_start_ap(struct wiphy *wiphy, struct net_device *ndev,
 			goto exit;
 		}
 
+		if (crypto->psk) {
+			brcmf_dbg(INFO, "using PSK offload\n");
+			profile->use_fwauth |= BIT(BRCMF_PROFILE_FWAUTH_PSK);
+			err = brcmf_set_pmk(ifp, crypto->psk,
+					    BRCMF_WSEC_MAX_PSK_LEN);
+			if (err < 0)
+				goto exit;
+		}
+		if (profile->use_fwauth == 0)
+			profile->use_fwauth = BIT(BRCMF_PROFILE_FWAUTH_NONE);
+
 		err = brcmf_parse_configure_security(ifp, settings,
 						     NL80211_IFTYPE_AP);
 		if (err < 0) {
@@ -4904,6 +4917,7 @@ static int brcmf_cfg80211_stop_ap(struct wiphy *wiphy, struct net_device *ndev)
 	struct brcmf_cfg80211_info *cfg = wiphy_to_cfg(wiphy);
 	struct brcmf_if *ifp = netdev_priv(ndev);
 	struct brcmf_pub *drvr = cfg->pub;
+	struct brcmf_cfg80211_profile *profile = &ifp->vif->profile;
 	s32 err;
 	struct brcmf_fil_bss_enable_le bss_enable;
 	struct brcmf_join_params join_params;
@@ -4915,6 +4929,12 @@ static int brcmf_cfg80211_stop_ap(struct wiphy *wiphy, struct net_device *ndev)
 		/* first to make sure they get processed by fw. */
 		msleep(400);
 
+		if (profile->use_fwauth != BIT(BRCMF_PROFILE_FWAUTH_NONE)) {
+			if (profile->use_fwauth & BIT(BRCMF_PROFILE_FWAUTH_PSK))
+				brcmf_set_pmk(ifp, NULL, 0);
+			profile->use_fwauth = BIT(BRCMF_PROFILE_FWAUTH_NONE);
+		}
+
 		if (ifp->vif->mbss) {
 			err = brcmf_fil_cmd_int_set(ifp, BRCMF_C_DOWN, 1);
 			return err;
@@ -7063,6 +7083,9 @@ static int brcmf_setup_wiphy(struct wiphy *wiphy, struct brcmf_if *ifp)
 			wiphy_ext_feature_set(wiphy,
 					      NL80211_EXT_FEATURE_SAE_OFFLOAD);
 	}
+	if (brcmf_feat_is_enabled(ifp, BRCMF_FEAT_FWAUTH))
+		wiphy_ext_feature_set(wiphy,
+				      NL80211_EXT_FEATURE_4WAY_HANDSHAKE_AP_PSK);
 	wiphy->mgmt_stypes = brcmf_txrx_stypes;
 	wiphy->max_remain_on_channel_duration = 5000;
 	if (brcmf_feat_is_enabled(ifp, BRCMF_FEAT_PNO)) {

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.h

@@ -128,6 +128,17 @@ enum brcmf_profile_fwsup {
 	BRCMF_PROFILE_FWSUP_SAE
 };
 
+/**
+ * enum brcmf_profile_fwauth - firmware authenticator profile
+ *
+ * @BRCMF_PROFILE_FWAUTH_NONE: no firmware authenticator
+ * @BRCMF_PROFILE_FWAUTH_PSK: authenticator for WPA/WPA2-PSK
+ */
+enum brcmf_profile_fwauth {
+	BRCMF_PROFILE_FWAUTH_NONE,
+	BRCMF_PROFILE_FWAUTH_PSK
+};
+
 /**
  * struct brcmf_cfg80211_profile - profile information.
  *
@@ -140,6 +151,7 @@ struct brcmf_cfg80211_profile {
 	struct brcmf_cfg80211_security sec;
 	struct brcmf_wsec_key key[BRCMF_MAX_DEFAULT_KEYS];
 	enum brcmf_profile_fwsup use_fwsup;
+	u16 use_fwauth;
 	bool is_ft;
 };
 

drivers/net/wireless/broadcom/brcm80211/brcmfmac/feature.c

@@ -42,6 +42,7 @@ static const struct brcmf_feat_fwcap brcmf_fwcap_map[] = {
 	{ BRCMF_FEAT_MONITOR_FMT_RADIOTAP, "rtap" },
 	{ BRCMF_FEAT_DOT11H, "802.11h" },
 	{ BRCMF_FEAT_SAE, "sae" },
+	{ BRCMF_FEAT_FWAUTH, "idauth" },
 };
 
 #ifdef DEBUG

drivers/net/wireless/broadcom/brcm80211/brcmfmac/feature.h

@@ -28,6 +28,7 @@
  * MONITOR_FMT_HW_RX_HDR: firmware provides monitor packets with hw/ucode header
  * DOT11H: firmware supports 802.11h
  * SAE: simultaneous authentication of equals
+ * FWAUTH: Firmware authenticator
  */
 #define BRCMF_FEAT_LIST \
 	BRCMF_FEAT_DEF(MBSS) \
@@ -49,7 +50,8 @@
 	BRCMF_FEAT_DEF(MONITOR_FMT_RADIOTAP) \
 	BRCMF_FEAT_DEF(MONITOR_FMT_HW_RX_HDR) \
 	BRCMF_FEAT_DEF(DOT11H) \
-	BRCMF_FEAT_DEF(SAE)
+	BRCMF_FEAT_DEF(SAE) \
+	BRCMF_FEAT_DEF(FWAUTH)
 
 /*
  * Quirks: