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From:   John Crispin <john@phrozen.org>
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org, John Crispin <john@phrozen.org>,
        Shashidhar Lakkavalli <slakkavalli@datto.com>
Subject: [PATCH V2 2/2] mac80211: add ADDBA_EXT responder support
Date:   Wed, 19 Jun 2019 07:30:20 +0200
Message-Id: <20190619053020.17121-3-john@phrozen.org>
In-Reply-To: <20190619053020.17121-1-john@phrozen.org>
References: <20190619053020.17121-1-john@phrozen.org>
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HE allows peers to negotiate the aggregation fragmentation level to be used
during transmission. The level can be 1-3. The Ext element is added behind
the ADDBA request inside the action frame. The responder will then reply
with the same level or a lower one if the requested one is not supported.
This patch only handles the responder part.

Signed-off-by: Shashidhar Lakkavalli <slakkavalli@datto.com>
Signed-off-by: John Crispin <john@phrozen.org>
---
 include/linux/ieee80211.h  |  3 ++
 net/mac80211/agg-rx.c      | 71 +++++++++++++++++++++++++++++++++-----
 net/mac80211/ht.c          |  2 +-
 net/mac80211/ieee80211_i.h |  3 +-
 4 files changed, 68 insertions(+), 11 deletions(-)

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index cf6b69bcbc52..a611f489e3cc 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -984,6 +984,8 @@ struct ieee80211_mgmt {
 					__le16 capab;
 					__le16 timeout;
 					__le16 start_seq_num;
+					/* followed by BA Extension */
+					u8 variable[0];
 				} __packed addba_req;
 				struct{
 					u8 action_code;
@@ -1742,6 +1744,7 @@ int ieee80211_get_vht_max_nss(struct ieee80211_vht_cap *cap,
 #define IEEE80211_HE_MAC_CAP0_DYNAMIC_FRAG_LEVEL_2		0x10
 #define IEEE80211_HE_MAC_CAP0_DYNAMIC_FRAG_LEVEL_3		0x18
 #define IEEE80211_HE_MAC_CAP0_DYNAMIC_FRAG_MASK			0x18
+#define IEEE80211_HE_MAC_CAP0_DYNAMIC_FRAG_SHIFT		3
 #define IEEE80211_HE_MAC_CAP0_MAX_NUM_FRAG_MSDU_1		0x00
 #define IEEE80211_HE_MAC_CAP0_MAX_NUM_FRAG_MSDU_2		0x20
 #define IEEE80211_HE_MAC_CAP0_MAX_NUM_FRAG_MSDU_4		0x40
diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index 6a4f154c99f6..e550c9029e74 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -181,17 +181,53 @@ static void sta_rx_agg_reorder_timer_expired(struct timer_list *t)
 	rcu_read_unlock();
 }
 
-static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *da, u16 tid,
+static void ieee80211_add_addbaext(struct ieee80211_sub_if_data *sdata,
+				   struct sk_buff *skb,
+				   const struct ieee80211_addba_ext_ie *req)
+{
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_addba_ext_ie *resp;
+	const struct ieee80211_sta_he_cap *he_cap;
+	u8 frag_level, cap_frag_level;
+	u8 *pos;
+
+	sband = ieee80211_get_sband(sdata);
+	he_cap = ieee80211_get_he_iftype_cap(sband, sdata->vif.type);
+	if (!he_cap)
+		return;
+
+	pos = skb_put_zero(skb, 2 + sizeof(struct ieee80211_addba_ext_ie));
+	*pos++ = WLAN_EID_ADDBA_EXT;
+	*pos++ = sizeof(struct ieee80211_addba_ext_ie);
+	resp = (struct ieee80211_addba_ext_ie *)pos;
+	resp->data = req->data & IEEE80211_ADDBA_EXT_NO_FRAG;
+
+	frag_level = (req->data & IEEE80211_ADDBA_EXT_FRAG_LEVEL_MASK) >>
+		     IEEE80211_ADDBA_EXT_FRAG_LEVEL_SHIFT;
+	cap_frag_level = (he_cap->he_cap_elem.mac_cap_info[0] &
+			  IEEE80211_HE_MAC_CAP0_DYNAMIC_FRAG_MASK) >>
+			 IEEE80211_HE_MAC_CAP0_DYNAMIC_FRAG_SHIFT;
+	if (frag_level > cap_frag_level)
+		frag_level = cap_frag_level;
+	resp->data |= (frag_level << IEEE80211_ADDBA_EXT_FRAG_LEVEL_SHIFT) &
+		      IEEE80211_ADDBA_EXT_FRAG_LEVEL_MASK;
+}
+
+static void ieee80211_send_addba_resp(struct sta_info *sta, u8 *da, u16 tid,
 				      u8 dialog_token, u16 status, u16 policy,
-				      u16 buf_size, u16 timeout)
+				      u16 buf_size, u16 timeout,
+				      const struct ieee80211_addba_ext_ie *addbaext)
 {
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	struct ieee80211_local *local = sdata->local;
 	struct sk_buff *skb;
 	struct ieee80211_mgmt *mgmt;
 	bool amsdu = ieee80211_hw_check(&local->hw, SUPPORTS_AMSDU_IN_AMPDU);
 	u16 capab;
 
-	skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
+	skb = dev_alloc_skb(sizeof(*mgmt) +
+		    (addbaext ? 2 + sizeof(struct ieee80211_addba_ext_ie) : 0) +
+		    local->hw.extra_tx_headroom);
 	if (!skb)
 		return;
 
@@ -225,13 +261,17 @@ static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *d
 	mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
 	mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);
 
+	if (sta->sta.he_cap.has_he && addbaext)
+		ieee80211_add_addbaext(sdata, skb, addbaext);
+
 	ieee80211_tx_skb(sdata, skb);
 }
 
 void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 				      u8 dialog_token, u16 timeout,
 				      u16 start_seq_num, u16 ba_policy, u16 tid,
-				      u16 buf_size, bool tx, bool auto_seq)
+				      u16 buf_size, bool tx, bool auto_seq,
+				      const struct ieee80211_addba_ext_ie *addbaext)
 {
 	struct ieee80211_local *local = sta->sdata->local;
 	struct tid_ampdu_rx *tid_agg_rx;
@@ -413,21 +453,22 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 	}
 
 	if (tx)
-		ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
+		ieee80211_send_addba_resp(sta, sta->sta.addr, tid,
 					  dialog_token, status, 1, buf_size,
-					  timeout);
+					  timeout, addbaext);
 }
 
 static void __ieee80211_start_rx_ba_session(struct sta_info *sta,
 					    u8 dialog_token, u16 timeout,
 					    u16 start_seq_num, u16 ba_policy,
 					    u16 tid, u16 buf_size, bool tx,
-					    bool auto_seq)
+					    bool auto_seq,
+					    const struct ieee80211_addba_ext_ie *addbaext)
 {
 	mutex_lock(&sta->ampdu_mlme.mtx);
 	___ieee80211_start_rx_ba_session(sta, dialog_token, timeout,
 					 start_seq_num, ba_policy, tid,
-					 buf_size, tx, auto_seq);
+					 buf_size, tx, auto_seq, addbaext);
 	mutex_unlock(&sta->ampdu_mlme.mtx);
 }
 
@@ -437,7 +478,9 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 				     size_t len)
 {
 	u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num;
+	struct ieee802_11_elems elems;
 	u8 dialog_token;
+	int ies_len;
 
 	/* extract session parameters from addba request frame */
 	dialog_token = mgmt->u.action.u.addba_req.dialog_token;
@@ -450,9 +493,19 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 
+	ies_len = len - offsetof(struct ieee80211_mgmt,
+				 u.action.u.addba_req.variable);
+	if (ies_len) {
+		ieee802_11_parse_elems(mgmt->u.action.u.addba_req.variable,
+				ies_len, true, &elems, mgmt->bssid, NULL);
+		if (elems.parse_error)
+			return;
+	}
+
 	__ieee80211_start_rx_ba_session(sta, dialog_token, timeout,
 					start_seq_num, ba_policy, tid,
-					buf_size, true, false);
+					buf_size, true, false,
+					elems.addba_ext_ie);
 }
 
 void ieee80211_manage_rx_ba_offl(struct ieee80211_vif *vif,
diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index c62101857b9b..3ea08e7ba0d1 100644
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c
@@ -362,7 +362,7 @@ void ieee80211_ba_session_work(struct work_struct *work)
 				       sta->ampdu_mlme.tid_rx_manage_offl))
 			___ieee80211_start_rx_ba_session(sta, 0, 0, 0, 1, tid,
 							 IEEE80211_MAX_AMPDU_BUF_HT,
-							 false, true);
+							 false, true, NULL);
 
 		if (test_and_clear_bit(tid + IEEE80211_NUM_TIDS,
 				       sta->ampdu_mlme.tid_rx_manage_offl))
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index acbf5384ad15..4b94c24b7524 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1814,7 +1814,8 @@ void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
 				      u8 dialog_token, u16 timeout,
 				      u16 start_seq_num, u16 ba_policy, u16 tid,
-				      u16 buf_size, bool tx, bool auto_seq);
+				      u16 buf_size, bool tx, bool auto_seq,
+				      const struct ieee80211_addba_ext_ie *addbaext);
 void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta,
 					 enum ieee80211_agg_stop_reason reason);
 void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,
-- 
2.20.1