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>

1 files changed, 166 insertions, 4 deletions

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;