mac80211: add an optimization for fast-rx support

Signed-off-by: Felix Fietkau <[email protected]>

package/kernel/mac80211/patches/335-mac80211-support-A-MSDU-in-fast-rx.patch

@@ -0,0 +1,207 @@
+From: Felix Fietkau <[email protected]>
+Date: Mon, 26 Feb 2018 22:09:29 +0100
+Subject: [PATCH] mac80211: support A-MSDU in fast-rx
+
+Only works if the IV was stripped from packets. Create a smaller
+variant of ieee80211_rx_h_amsdu, which bypasses checks already done
+within the fast-rx context.
+
+Signed-off-by: Felix Fietkau <[email protected]>
+---
+
+--- a/net/mac80211/rx.c
++++ b/net/mac80211/rx.c
+@@ -2358,39 +2358,17 @@ ieee80211_deliver_skb(struct ieee80211_r
+ }
+ 
+ static ieee80211_rx_result debug_noinline
+-ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
++__ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
+ {
+ 	struct net_device *dev = rx->sdata->dev;
+ 	struct sk_buff *skb = rx->skb;
+ 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+ 	__le16 fc = hdr->frame_control;
+ 	struct sk_buff_head frame_list;
+-	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
+ 	struct ethhdr ethhdr;
+ 	const u8 *check_da = ethhdr.h_dest, *check_sa = ethhdr.h_source;
+ 
+-	if (unlikely(!ieee80211_is_data(fc)))
+-		return RX_CONTINUE;
+-
+-	if (unlikely(!ieee80211_is_data_present(fc)))
+-		return RX_DROP_MONITOR;
+-
+-	if (!(status->rx_flags & IEEE80211_RX_AMSDU))
+-		return RX_CONTINUE;
+-
+ 	if (unlikely(ieee80211_has_a4(hdr->frame_control))) {
+-		switch (rx->sdata->vif.type) {
+-		case NL80211_IFTYPE_AP_VLAN:
+-			if (!rx->sdata->u.vlan.sta)
+-				return RX_DROP_UNUSABLE;
+-			break;
+-		case NL80211_IFTYPE_STATION:
+-			if (!rx->sdata->u.mgd.use_4addr)
+-				return RX_DROP_UNUSABLE;
+-			break;
+-		default:
+-			return RX_DROP_UNUSABLE;
+-		}
+ 		check_da = NULL;
+ 		check_sa = NULL;
+ 	} else switch (rx->sdata->vif.type) {
+@@ -2410,9 +2388,6 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx
+ 			break;
+ 	}
+ 
+-	if (is_multicast_ether_addr(hdr->addr1))
+-		return RX_DROP_UNUSABLE;
+-
+ 	skb->dev = dev;
+ 	__skb_queue_head_init(&frame_list);
+ 
+@@ -2440,6 +2415,44 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx
+ 	return RX_QUEUED;
+ }
+ 
++static ieee80211_rx_result debug_noinline
++ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
++{
++	struct sk_buff *skb = rx->skb;
++	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
++	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
++	__le16 fc = hdr->frame_control;
++
++	if (!(status->rx_flags & IEEE80211_RX_AMSDU))
++		return RX_CONTINUE;
++
++	if (unlikely(!ieee80211_is_data(fc)))
++		return RX_CONTINUE;
++
++	if (unlikely(!ieee80211_is_data_present(fc)))
++		return RX_DROP_MONITOR;
++
++	if (unlikely(ieee80211_has_a4(hdr->frame_control))) {
++		switch (rx->sdata->vif.type) {
++		case NL80211_IFTYPE_AP_VLAN:
++			if (!rx->sdata->u.vlan.sta)
++				return RX_DROP_UNUSABLE;
++			break;
++		case NL80211_IFTYPE_STATION:
++			if (!rx->sdata->u.mgd.use_4addr)
++				return RX_DROP_UNUSABLE;
++			break;
++		default:
++			return RX_DROP_UNUSABLE;
++		}
++	}
++
++	if (is_multicast_ether_addr(hdr->addr1))
++		return RX_DROP_UNUSABLE;
++
++	return __ieee80211_rx_h_amsdu(rx);
++}
++
+ #ifdef CPTCFG_MAC80211_MESH
+ static ieee80211_rx_result
+ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
+@@ -3899,6 +3912,7 @@ static bool ieee80211_invoke_fast_rx(str
+ 		u8 sa[ETH_ALEN];
+ 	} addrs __aligned(2);
+ 	struct ieee80211_sta_rx_stats *stats = &sta->rx_stats;
++	int res;
+ 
+ 	if (fast_rx->uses_rss)
+ 		stats = this_cpu_ptr(sta->pcpu_rx_stats);
+@@ -3920,10 +3934,6 @@ static bool ieee80211_invoke_fast_rx(str
+ 	    (status->flag & FAST_RX_CRYPT_FLAGS) != FAST_RX_CRYPT_FLAGS)
+ 		return false;
+ 
+-	/* we don't deal with A-MSDU deaggregation here */
+-	if (status->rx_flags & IEEE80211_RX_AMSDU)
+-		return false;
+-
+ 	if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
+ 		return false;
+ 
+@@ -3951,25 +3961,31 @@ static bool ieee80211_invoke_fast_rx(str
+ 	 * and strip the IV/MIC if necessary
+ 	 */
+ 	if (fast_rx->key && !(status->flag & RX_FLAG_IV_STRIPPED)) {
++		if (status->rx_flags & IEEE80211_RX_AMSDU)
++			return false;
++
+ 		/* GCMP header length is the same */
+ 		snap_offs += IEEE80211_CCMP_HDR_LEN;
+ 	}
+ 
+-	if (!pskb_may_pull(skb, snap_offs + sizeof(*payload)))
+-		goto drop;
+-	payload = (void *)(skb->data + snap_offs);
++	if (!(status->rx_flags & IEEE80211_RX_AMSDU)) {
++		if (!pskb_may_pull(skb, snap_offs + sizeof(*payload)))
++			goto drop;
+ 
+-	if (!ether_addr_equal(payload->snap, fast_rx->rfc1042_hdr))
+-		return false;
++		payload = (void *)(skb->data + snap_offs);
+ 
+-	/* Don't handle these here since they require special code.
+-	 * Accept AARP and IPX even though they should come with a
+-	 * bridge-tunnel header - but if we get them this way then
+-	 * there's little point in discarding them.
+-	 */
+-	if (unlikely(payload->proto == cpu_to_be16(ETH_P_TDLS) ||
+-		     payload->proto == fast_rx->control_port_protocol))
+-		return false;
++		if (!ether_addr_equal(payload->snap, fast_rx->rfc1042_hdr))
++			return false;
++
++		/* Don't handle these here since they require special code.
++		 * Accept AARP and IPX even though they should come with a
++		 * bridge-tunnel header - but if we get them this way then
++		 * there's little point in discarding them.
++		 */
++		if (unlikely(payload->proto == cpu_to_be16(ETH_P_TDLS) ||
++			     payload->proto == fast_rx->control_port_protocol))
++			return false;
++	}
+ 
+ 	/* after this point, don't punt to the slowpath! */
+ 
+@@ -3983,12 +3999,6 @@ static bool ieee80211_invoke_fast_rx(str
+ 	}
+ 
+ 	/* statistics part of ieee80211_rx_h_sta_process() */
+-	stats->last_rx = jiffies;
+-	stats->last_rate = sta_stats_encode_rate(status);
+-
+-	stats->fragments++;
+-	stats->packets++;
+-
+ 	if (!(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
+ 		stats->last_signal = status->signal;
+ 		if (!fast_rx->uses_rss)
+@@ -4017,6 +4027,20 @@ static bool ieee80211_invoke_fast_rx(str
+ 	if (rx->key && !ieee80211_has_protected(hdr->frame_control))
+ 		goto drop;
+ 
++	if (status->rx_flags & IEEE80211_RX_AMSDU) {
++		res = __ieee80211_rx_h_amsdu(rx);
++		if (res != RX_QUEUED)
++			goto drop;
++
++		return true;
++	}
++
++	stats->last_rx = jiffies;
++	stats->last_rate = sta_stats_encode_rate(status);
++
++	stats->fragments++;
++	stats->packets++;
++
+ 	/* do the header conversion - first grab the addresses */
+ 	ether_addr_copy(addrs.da, skb->data + fast_rx->da_offs);
+ 	ether_addr_copy(addrs.sa, skb->data + fast_rx->sa_offs);