mac80211: add 802.11 encapsulation offloading support

This patch adds a new transmit path for hardware that supports 802.11
encapsulation offloading. In those cases 802.3 frames get passed
directly to the driver allowing the hardware to handle the encapsulation.
Some features such as monitor mode and TKIP would break when encapsulation
offloading is enabled. If any of these get enabled, the code will alwyas
fallback to the normal sw encapsulation data path.

The patch defines a secondary netdev_ops struct that the device gets
assigned if 802.11 encap support is available and enabled. The driver
needs to enable the support on a per vif basis if it finds that all
pre-reqs are meet.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Signed-off-by: John Crispin <john@phrozen.org>
Link: https://lore.kernel.org/r/20191125100438.16539-1-john@phrozen.org
[reword comments, remove SUPPORTS_80211_ENCAP HW flag, minor cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

5 files changed, 324 insertions, 4 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index ad15b3be8bb3..e3cf24cb4615 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -984,6 +984,8 @@ struct ieee80211_sub_if_data {
 	} debugfs;
 #endif
 
+	bool hw_80211_encap;
+
 	/* must be last, dynamically sized area in this! */
 	struct ieee80211_vif vif;
 };
@@ -1762,6 +1764,8 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
 					 struct net_device *dev);
 netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
 				       struct net_device *dev);
+netdev_tx_t ieee80211_subif_start_xmit_8023(struct sk_buff *skb,
+					    struct net_device *dev);
 void __ieee80211_subif_start_xmit(struct sk_buff *skb,
 				  struct net_device *dev,
 				  u32 info_flags,
@@ -1948,6 +1952,11 @@ void __ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
 				 struct sk_buff *skb, int tid,
 				 enum nl80211_band band, u32 txdata_flags);
 
+/* sta_out needs to be checked for ERR_PTR() before using */
+int ieee80211_lookup_ra_sta(struct ieee80211_sub_if_data *sdata,
+			    struct sk_buff *skb,
+			    struct sta_info **sta_out);
+
 static inline void
 ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
 			  struct sk_buff *skb, int tid,
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index af8b09214786..9b833e170c20 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1205,6 +1205,72 @@ static const struct net_device_ops ieee80211_monitorif_ops = {
 	.ndo_get_stats64	= ieee80211_get_stats64,
 };
 
+static const struct net_device_ops ieee80211_dataif_8023_ops = {
+	.ndo_open		= ieee80211_open,
+	.ndo_stop		= ieee80211_stop,
+	.ndo_uninit		= ieee80211_uninit,
+	.ndo_start_xmit		= ieee80211_subif_start_xmit_8023,
+	.ndo_set_rx_mode	= ieee80211_set_multicast_list,
+	.ndo_set_mac_address	= ieee80211_change_mac,
+	.ndo_select_queue	= ieee80211_netdev_select_queue,
+	.ndo_get_stats64	= ieee80211_get_stats64,
+};
+
+static void __ieee80211_set_hw_80211_encap(struct ieee80211_sub_if_data *sdata,
+					   bool enable)
+{
+	sdata->dev->netdev_ops = enable ? &ieee80211_dataif_8023_ops :
+					  &ieee80211_dataif_ops;
+	sdata->hw_80211_encap = enable;
+}
+
+bool ieee80211_set_hw_80211_encap(struct ieee80211_vif *vif, bool enable)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_sub_if_data *iter;
+	struct ieee80211_key *key;
+
+	mutex_lock(&local->iflist_mtx);
+	list_for_each_entry(iter, &local->interfaces, list) {
+		struct ieee80211_sub_if_data *disable = NULL;
+
+		if (vif->type == NL80211_IFTYPE_MONITOR) {
+			disable = iter;
+			__ieee80211_set_hw_80211_encap(iter, false);
+		} else if (iter->vif.type == NL80211_IFTYPE_MONITOR) {
+			disable = sdata;
+			enable = false;
+		}
+		if (disable)
+			sdata_dbg(disable,
+				  "disable hw 80211 encap due to mon co-exist\n");
+	}
+	mutex_unlock(&local->iflist_mtx);
+
+	if (enable == sdata->hw_80211_encap)
+		return enable;
+
+	if (!sdata->dev)
+		return false;
+
+	if (!ieee80211_hw_check(&local->hw, SUPPORTS_TX_FRAG) &&
+	    (local->hw.wiphy->frag_threshold != (u32)-1))
+		enable = false;
+
+	mutex_lock(&sdata->local->key_mtx);
+	list_for_each_entry(key, &sdata->key_list, list) {
+		if (key->conf.cipher == WLAN_CIPHER_SUITE_TKIP)
+			enable = false;
+	}
+	mutex_unlock(&sdata->local->key_mtx);
+
+	__ieee80211_set_hw_80211_encap(sdata, enable);
+
+	return enable;
+}
+EXPORT_SYMBOL(ieee80211_set_hw_80211_encap);
+
 static void ieee80211_if_free(struct net_device *dev)
 {
 	free_percpu(dev->tstats);
@@ -1404,6 +1470,7 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
 	sdata->vif.bss_conf.idle = true;
 
 	sdata->noack_map = 0;
+	sdata->hw_80211_encap = false;
 
 	/* only monitor/p2p-device differ */
 	if (sdata->dev) {
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 0f889b919b06..9a3a6b95fa27 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -177,6 +177,13 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 		}
 	}
 
+	/* TKIP countermeasures don't work in encap offload mode */
+	if (key->conf.cipher == WLAN_CIPHER_SUITE_TKIP &&
+	    sdata->hw_80211_encap) {
+		sdata_dbg(sdata, "TKIP is not allowed in hw 80211 encap mode\n");
+		return -EINVAL;
+	}
+
 	ret = drv_set_key(key->local, SET_KEY, sdata,
 			  sta ? &sta->sta : NULL, &key->conf);
 
@@ -203,6 +210,10 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 			  key->conf.keyidx,
 			  sta ? sta->sta.addr : bcast_addr, ret);
 
+	/* cannot do software crypto with encapsulation offload */
+	if (sdata->hw_80211_encap)
+		return -EINVAL;
+
  out_unsupported:
 	switch (key->conf.cipher) {
 	case WLAN_CIPHER_SUITE_WEP40:
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index b720feaf9a74..0344b82a34f5 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -1198,6 +1198,77 @@ void ieee80211_tx_rate_update(struct ieee80211_hw *hw,
 }
 EXPORT_SYMBOL(ieee80211_tx_rate_update);
 
+void ieee80211_tx_status_8023(struct ieee80211_hw *hw,
+			      struct ieee80211_vif *vif,
+			      struct sk_buff *skb)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct sta_info *sta;
+	int retry_count;
+	int rates_idx;
+	bool acked;
+
+	sdata = vif_to_sdata(vif);
+
+	acked = info->flags & IEEE80211_TX_STAT_ACK;
+	rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
+
+	rcu_read_lock();
+
+	if (ieee80211_lookup_ra_sta(sdata, skb, &sta))
+		goto counters_update;
+
+	if (IS_ERR(sta))
+		goto counters_update;
+
+	if (!acked)
+		sta->status_stats.retry_failed++;
+
+	if (rates_idx != -1)
+		sta->tx_stats.last_rate = info->status.rates[rates_idx];
+
+	sta->status_stats.retry_count += retry_count;
+
+	if (ieee80211_hw_check(hw, REPORTS_TX_ACK_STATUS)) {
+		if (acked && vif->type == NL80211_IFTYPE_STATION)
+			ieee80211_sta_reset_conn_monitor(sdata);
+
+		sta->status_stats.last_ack = jiffies;
+		if (info->flags & IEEE80211_TX_STAT_ACK) {
+			if (sta->status_stats.lost_packets)
+				sta->status_stats.lost_packets = 0;
+
+			if (test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH))
+				sta->status_stats.last_tdls_pkt_time = jiffies;
+		} else {
+			ieee80211_lost_packet(sta, info);
+		}
+	}
+
+counters_update:
+	rcu_read_unlock();
+	ieee80211_led_tx(local);
+
+	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
+	    !(info->flags & IEEE80211_TX_STAT_NOACK_TRANSMITTED))
+		goto skip_stats_update;
+
+	I802_DEBUG_INC(local->dot11TransmittedFrameCount);
+	if (is_multicast_ether_addr(skb->data))
+		I802_DEBUG_INC(local->dot11MulticastTransmittedFrameCount);
+	if (retry_count > 0)
+		I802_DEBUG_INC(local->dot11RetryCount);
+	if (retry_count > 1)
+		I802_DEBUG_INC(local->dot11MultipleRetryCount);
+
+skip_stats_update:
+	ieee80211_report_used_skb(local, skb, false);
+	dev_kfree_skb(skb);
+}
+EXPORT_SYMBOL(ieee80211_tx_status_8023);
+
 void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
 {
 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index b696b9136f4c..b31b5078f656 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1250,7 +1250,8 @@ static struct txq_info *ieee80211_get_txq(struct ieee80211_local *local,
 	    (info->control.flags & IEEE80211_TX_CTRL_PS_RESPONSE))
 		return NULL;
 
-	if (unlikely(!ieee80211_is_data_present(hdr->frame_control))) {
+	if (!(info->control.flags & IEEE80211_TX_CTRL_HW_80211_ENCAP) &&
+	    unlikely(!ieee80211_is_data_present(hdr->frame_control))) {
 		if ((!ieee80211_is_mgmt(hdr->frame_control) ||
 		     ieee80211_is_bufferable_mmpdu(hdr->frame_control) ||
 		     vif->type == NL80211_IFTYPE_STATION) &&
@@ -2351,9 +2352,9 @@ static inline bool ieee80211_is_tdls_setup(struct sk_buff *skb)
 	       skb->data[14] == WLAN_TDLS_SNAP_RFTYPE;
 }
 
-static int ieee80211_lookup_ra_sta(struct ieee80211_sub_if_data *sdata,
-				   struct sk_buff *skb,
-				   struct sta_info **sta_out)
+int ieee80211_lookup_ra_sta(struct ieee80211_sub_if_data *sdata,
+			    struct sk_buff *skb,
+			    struct sta_info **sta_out)
 {
 	struct sta_info *sta;
 
@@ -3607,6 +3608,9 @@ begin:
 	else
 		info->flags &= ~IEEE80211_TX_CTL_AMPDU;
 
+	if (info->control.flags & IEEE80211_TX_CTRL_HW_80211_ENCAP)
+		goto encap_out;
+
 	if (info->control.flags & IEEE80211_TX_CTRL_FAST_XMIT) {
 		struct sta_info *sta = container_of(txq->sta, struct sta_info,
 						    sta);
@@ -3666,6 +3670,7 @@ begin:
 		break;
 	}
 
+encap_out:
 	IEEE80211_SKB_CB(skb)->control.vif = vif;
 
 	if (local->airtime_flags & AIRTIME_USE_AQL) {
@@ -4097,6 +4102,153 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
 	return NETDEV_TX_OK;
 }
 
+static bool ieee80211_tx_8023(struct ieee80211_sub_if_data *sdata,
+			      struct sk_buff *skb, int led_len,
+			      struct sta_info *sta,
+			      bool txpending)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_tx_control control = {};
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_sta *pubsta = NULL;
+	unsigned long flags;
+	int q = info->hw_queue;
+
+	if (ieee80211_queue_skb(local, sdata, sta, skb))
+		return true;
+
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+
+	if (local->queue_stop_reasons[q] ||
+	    (!txpending && !skb_queue_empty(&local->pending[q]))) {
+		if (txpending)
+			skb_queue_head(&local->pending[q], skb);
+		else
+			skb_queue_tail(&local->pending[q], skb);
+
+		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+
+		return false;
+	}
+
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+
+	if (sta && sta->uploaded)
+		pubsta = &sta->sta;
+
+	control.sta = pubsta;
+
+	drv_tx(local, &control, skb);
+
+	return true;
+}
+
+static void ieee80211_8023_xmit(struct ieee80211_sub_if_data *sdata,
+				struct net_device *dev, struct sta_info *sta,
+				struct sk_buff *skb)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ethhdr *ehdr = (struct ethhdr *)skb->data;
+	struct ieee80211_local *local = sdata->local;
+	bool authorized = false;
+	bool multicast;
+	unsigned char *ra = ehdr->h_dest;
+
+	if (IS_ERR(sta) || (sta && !sta->uploaded))
+		sta = NULL;
+
+	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
+	    (!sta || !test_sta_flag(sta, WLAN_STA_TDLS_PEER)))
+		ra = sdata->u.mgd.bssid;
+
+	if (!is_valid_ether_addr(ra))
+		goto out_free;
+
+	multicast = is_multicast_ether_addr(ra);
+
+	if (sta)
+		authorized = test_sta_flag(sta, WLAN_STA_AUTHORIZED);
+
+	if (!multicast && !authorized &&
+	    (ehdr->h_proto != sdata->control_port_protocol ||
+	     !ether_addr_equal(sdata->vif.addr, ehdr->h_source)))
+		goto out_free;
+
+	if (multicast && sdata->vif.type == NL80211_IFTYPE_AP &&
+	    !atomic_read(&sdata->u.ap.num_mcast_sta))
+		goto out_free;
+
+	if (unlikely(test_bit(SCAN_SW_SCANNING, &local->scanning)) &&
+	    test_bit(SDATA_STATE_OFFCHANNEL, &sdata->state))
+		goto out_free;
+
+	if (unlikely(!multicast && skb->sk &&
+		     skb_shinfo(skb)->tx_flags & SKBTX_WIFI_STATUS))
+		ieee80211_store_ack_skb(local, skb, &info->flags);
+
+	memset(info, 0, sizeof(*info));
+
+	if (unlikely(sdata->control_port_protocol == ehdr->h_proto)) {
+		if (sdata->control_port_no_encrypt)
+			info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
+		info->control.flags |= IEEE80211_TX_CTRL_PORT_CTRL_PROTO;
+	}
+
+	if (multicast)
+		info->flags |= IEEE80211_TX_CTL_NO_ACK;
+
+	info->hw_queue = sdata->vif.hw_queue[skb_get_queue_mapping(skb)];
+
+	ieee80211_tx_stats(dev, skb->len);
+
+	if (sta) {
+		sta->tx_stats.bytes[skb_get_queue_mapping(skb)] += skb->len;
+		sta->tx_stats.packets[skb_get_queue_mapping(skb)]++;
+	}
+
+	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+		sdata = container_of(sdata->bss,
+				     struct ieee80211_sub_if_data, u.ap);
+
+	info->control.flags |= IEEE80211_TX_CTRL_HW_80211_ENCAP;
+	info->control.vif = &sdata->vif;
+
+	ieee80211_tx_8023(sdata, skb, skb->len, sta, false);
+
+	return;
+
+out_free:
+	kfree_skb(skb);
+}
+
+netdev_tx_t ieee80211_subif_start_xmit_8023(struct sk_buff *skb,
+					    struct net_device *dev)
+{
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	struct sta_info *sta;
+
+	if (WARN_ON(!sdata->hw_80211_encap)) {
+		kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
+	if (unlikely(skb->len < ETH_HLEN)) {
+		kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
+	rcu_read_lock();
+
+	if (ieee80211_lookup_ra_sta(sdata, skb, &sta))
+		kfree_skb(skb);
+	else
+		ieee80211_8023_xmit(sdata, dev, sta, skb);
+
+	rcu_read_unlock();
+
+	return NETDEV_TX_OK;
+}
+
 struct sk_buff *
 ieee80211_build_data_template(struct ieee80211_sub_if_data *sdata,
 			      struct sk_buff *skb, u32 info_flags)
@@ -4175,6 +4327,16 @@ static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
 		}
 		info->band = chanctx_conf->def.chan->band;
 		result = ieee80211_tx(sdata, NULL, skb, true, 0);
+	} else if (info->control.flags & IEEE80211_TX_CTRL_HW_80211_ENCAP) {
+		if (ieee80211_lookup_ra_sta(sdata, skb, &sta)) {
+			dev_kfree_skb(skb);
+			return true;
+		}
+
+		if (IS_ERR(sta) || (sta && !sta->uploaded))
+			sta = NULL;
+
+		result = ieee80211_tx_8023(sdata, skb, skb->len, sta, true);
 	} else {
 		struct sk_buff_head skbs;