From:   Felix Fietkau <nbd@nbd.name>
To:     linux-wireless@vger.kernel.org
Cc:     johannes@sipsolutions.net
Subject: [PATCH 4/5] wifi: mac80211: fix receiving A-MSDU frames on mesh interfaces
Date:   Mon, 13 Feb 2023 11:08:54 +0100
Message-Id: <20230213100855.34315-4-nbd@nbd.name>
In-Reply-To: <20230213100855.34315-1-nbd@nbd.name>
References: <20230213100855.34315-1-nbd@nbd.name>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The current mac80211 mesh A-MSDU receive path fails to parse A-MSDU packets
on mesh interfaces, because it assumes that the Mesh Control field is always
directly after the 802.11 header.
802.11-2020 9.3.2.2.2 Figure 9-70 shows that the Mesh Control field is
actually part of the A-MSDU subframe header.
This makes more sense, since it allows packets for multiple different
destinations to be included in the same A-MSDU, as long as RA and TID are
still the same.
Another issue is the fact that the A-MSDU subframe length field was apparently
accidentally defined as little-endian in the standard.

In order to fix this, the mesh forwarding path needs happen at a different
point in the receive path.

ieee80211_data_to_8023_exthdr is changed to ignore the mesh control field
and leave it in after the ethernet header. This also affects the source/dest
MAC address fields, which now in the case of mesh point to the mesh SA/DA.

ieee80211_amsdu_to_8023s is changed to deal with the endian difference and
to add the Mesh Control length to the subframe length, since it's not covered
by the MSDU length field.

With these changes, the mac80211 will get the same packet structure for
converted regular data packets and unpacked A-MSDU subframes.

The mesh forwarding checks are now only performed after the A-MSDU decap.
For locally received packets, the Mesh Control header is stripped away.
For forwarded packets, a new 802.11 header gets added.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 .../wireless/marvell/mwifiex/11n_rxreorder.c  |   2 +-
 include/net/cfg80211.h                        |  27 +-
 net/mac80211/rx.c                             | 350 ++++++++++--------
 net/wireless/util.c                           | 120 +++---
 4 files changed, 297 insertions(+), 202 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/11n_rxreorder.c b/drivers/net/wireless/marvell/mwifiex/11n_rxreorder.c
index a04b66284af4..391793a16adc 100644
--- a/drivers/net/wireless/marvell/mwifiex/11n_rxreorder.c
+++ b/drivers/net/wireless/marvell/mwifiex/11n_rxreorder.c
@@ -33,7 +33,7 @@ static int mwifiex_11n_dispatch_amsdu_pkt(struct mwifiex_private *priv,
 		skb_trim(skb, le16_to_cpu(local_rx_pd->rx_pkt_length));
 
 		ieee80211_amsdu_to_8023s(skb, &list, priv->curr_addr,
-					 priv->wdev.iftype, 0, NULL, NULL);
+					 priv->wdev.iftype, 0, NULL, NULL, false);
 
 		while (!skb_queue_empty(&list)) {
 			struct rx_packet_hdr *rx_hdr;
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 54a77d906b2d..8794016cb134 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -6197,11 +6197,36 @@ static inline int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
  * @extra_headroom: The hardware extra headroom for SKBs in the @list.
  * @check_da: DA to check in the inner ethernet header, or NULL
  * @check_sa: SA to check in the inner ethernet header, or NULL
+ * @mesh_control: A-MSDU subframe header includes the mesh control field
  */
 void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
 			      const u8 *addr, enum nl80211_iftype iftype,
 			      const unsigned int extra_headroom,
-			      const u8 *check_da, const u8 *check_sa);
+			      const u8 *check_da, const u8 *check_sa,
+			      bool mesh_control);
+
+/**
+ * ieee80211_get_8023_tunnel_proto - get RFC1042 or bridge tunnel encap protocol
+ *
+ * Check for RFC1042 or bridge tunnel header and fetch the encapsulated
+ * protocol.
+ *
+ * @hdr: pointer to the MSDU payload
+ * @proto: destination pointer to store the protocol
+ * Return: true if encapsulation was found
+ */
+bool ieee80211_get_8023_tunnel_proto(const void *hdr, __be16 *proto);
+
+/**
+ * ieee80211_strip_8023_mesh_hdr - strip mesh header from converted 802.3 frames
+ *
+ * Strip the mesh header, which was left in by ieee80211_data_to_8023 as part
+ * of the MSDU data. Also move any source/destination addresses from the mesh
+ * header to the ethernet header (if present).
+ *
+ * @skb: The 802.3 frame with embedded mesh header
+ */
+int ieee80211_strip_8023_mesh_hdr(struct sk_buff *skb);
 
 /**
  * cfg80211_classify8021d - determine the 802.1p/1d tag for a data frame
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 519bd9daea75..b5ee049e3197 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2720,6 +2720,174 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
 	}
 }
 
+static ieee80211_rx_result
+ieee80211_rx_mesh_data(struct ieee80211_sub_if_data *sdata, struct sta_info *sta,
+		       struct sk_buff *skb)
+{
+#ifdef CONFIG_MAC80211_MESH
+	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+	struct ieee80211_local *local = sdata->local;
+	uint16_t fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_QOS_DATA;
+	struct ieee80211_hdr hdr = {
+		.frame_control = cpu_to_le16(fc)
+	};
+	struct ieee80211_hdr *fwd_hdr;
+	struct ieee80211s_hdr *mesh_hdr;
+	struct ieee80211_tx_info *info;
+	struct sk_buff *fwd_skb;
+	struct ethhdr *eth;
+	bool multicast;
+	int tailroom = 0;
+	int hdrlen, mesh_hdrlen;
+	u8 *qos;
+
+	if (!ieee80211_vif_is_mesh(&sdata->vif))
+		return RX_CONTINUE;
+
+	if (!pskb_may_pull(skb, sizeof(*eth) + 6))
+		return RX_DROP_MONITOR;
+
+	mesh_hdr = (struct ieee80211s_hdr *)(skb->data + sizeof(*eth));
+	mesh_hdrlen = ieee80211_get_mesh_hdrlen(mesh_hdr);
+
+	if (!pskb_may_pull(skb, sizeof(*eth) + mesh_hdrlen))
+		return RX_DROP_MONITOR;
+
+	eth = (struct ethhdr *)skb->data;
+	multicast = is_multicast_ether_addr(eth->h_dest);
+
+	mesh_hdr = (struct ieee80211s_hdr *)(eth + 1);
+	if (!mesh_hdr->ttl)
+		return RX_DROP_MONITOR;
+
+	/* frame is in RMC, don't forward */
+	if (is_multicast_ether_addr(eth->h_dest) &&
+	    mesh_rmc_check(sdata, eth->h_source, mesh_hdr))
+		return RX_DROP_MONITOR;
+
+	/* Frame has reached destination.  Don't forward */
+	if (ether_addr_equal(sdata->vif.addr, eth->h_dest))
+		goto rx_accept;
+
+	if (!ifmsh->mshcfg.dot11MeshForwarding) {
+		if (is_multicast_ether_addr(eth->h_dest))
+			goto rx_accept;
+
+		return RX_DROP_MONITOR;
+	}
+
+	/* forward packet */
+	if (sdata->crypto_tx_tailroom_needed_cnt)
+		tailroom = IEEE80211_ENCRYPT_TAILROOM;
+
+	if (!--mesh_hdr->ttl) {
+		if (multicast)
+			goto rx_accept;
+
+		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_ttl);
+		return RX_DROP_MONITOR;
+	}
+
+	if (mesh_hdr->flags & MESH_FLAGS_AE) {
+		struct mesh_path *mppath;
+		char *proxied_addr;
+
+		if (multicast)
+			proxied_addr = mesh_hdr->eaddr1;
+		else if ((mesh_hdr->flags & MESH_FLAGS_AE) == MESH_FLAGS_AE_A5_A6)
+			/* has_a4 already checked in ieee80211_rx_mesh_check */
+			proxied_addr = mesh_hdr->eaddr2;
+		else
+			return RX_DROP_MONITOR;
+
+		rcu_read_lock();
+		mppath = mpp_path_lookup(sdata, proxied_addr);
+		if (!mppath) {
+			mpp_path_add(sdata, proxied_addr, eth->h_source);
+		} else {
+			spin_lock_bh(&mppath->state_lock);
+			if (!ether_addr_equal(mppath->mpp, eth->h_source))
+				memcpy(mppath->mpp, eth->h_source, ETH_ALEN);
+			mppath->exp_time = jiffies;
+			spin_unlock_bh(&mppath->state_lock);
+		}
+		rcu_read_unlock();
+	}
+
+	skb_set_queue_mapping(skb, ieee802_1d_to_ac[skb->priority]);
+
+	ieee80211_fill_mesh_addresses(&hdr, &hdr.frame_control,
+				      eth->h_dest, eth->h_source);
+	hdrlen = ieee80211_hdrlen(hdr.frame_control);
+	if (multicast) {
+		int extra_head = sizeof(struct ieee80211_hdr) - sizeof(*eth);
+
+		fwd_skb = skb_copy_expand(skb, local->tx_headroom + extra_head +
+					       IEEE80211_ENCRYPT_HEADROOM,
+					  tailroom, GFP_ATOMIC);
+		if (!fwd_skb)
+			goto rx_accept;
+	} else {
+		fwd_skb = skb;
+		skb = NULL;
+
+		if (skb_cow_head(fwd_skb, hdrlen - sizeof(struct ethhdr)))
+			return RX_DROP_UNUSABLE;
+	}
+
+	fwd_hdr = skb_push(fwd_skb, hdrlen - sizeof(struct ethhdr));
+	memcpy(fwd_hdr, &hdr, hdrlen - 2);
+	qos = ieee80211_get_qos_ctl(fwd_hdr);
+	qos[0] = qos[1] = 0;
+
+	skb_reset_mac_header(fwd_skb);
+	hdrlen += mesh_hdrlen;
+	if (ieee80211_get_8023_tunnel_proto(fwd_skb->data + hdrlen,
+					    &fwd_skb->protocol))
+		hdrlen += ETH_ALEN;
+	else
+		fwd_skb->protocol = htons(fwd_skb->len - hdrlen);
+	skb_set_network_header(fwd_skb, hdrlen);
+
+	info = IEEE80211_SKB_CB(fwd_skb);
+	memset(info, 0, sizeof(*info));
+	info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
+	info->control.vif = &sdata->vif;
+	info->control.jiffies = jiffies;
+	if (multicast) {
+		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_mcast);
+		memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
+		/* update power mode indication when forwarding */
+		ieee80211_mps_set_frame_flags(sdata, NULL, fwd_hdr);
+	} else if (!mesh_nexthop_lookup(sdata, fwd_skb)) {
+		/* mesh power mode flags updated in mesh_nexthop_lookup */
+		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_unicast);
+	} else {
+		/* unable to resolve next hop */
+		if (sta)
+			mesh_path_error_tx(sdata, ifmsh->mshcfg.element_ttl,
+					   hdr.addr3, 0,
+					   WLAN_REASON_MESH_PATH_NOFORWARD,
+					   sta->sta.addr);
+		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_no_route);
+		kfree_skb(fwd_skb);
+		goto rx_accept;
+	}
+
+	IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_frames);
+	fwd_skb->dev = sdata->dev;
+	ieee80211_add_pending_skb(local, fwd_skb);
+
+rx_accept:
+	if (!skb)
+		return RX_QUEUED;
+
+	ieee80211_strip_8023_mesh_hdr(skb);
+#endif
+
+	return RX_CONTINUE;
+}
+
 static ieee80211_rx_result debug_noinline
 __ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx, u8 data_offset)
 {
@@ -2728,8 +2896,10 @@ __ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx, u8 data_offset)
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 	__le16 fc = hdr->frame_control;
 	struct sk_buff_head frame_list;
+	static ieee80211_rx_result res;
 	struct ethhdr ethhdr;
 	const u8 *check_da = ethhdr.h_dest, *check_sa = ethhdr.h_source;
+	bool mesh = false;
 
 	if (unlikely(ieee80211_has_a4(hdr->frame_control))) {
 		check_da = NULL;
@@ -2746,6 +2916,8 @@ __ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx, u8 data_offset)
 			break;
 		case NL80211_IFTYPE_MESH_POINT:
 			check_sa = NULL;
+			check_da = NULL;
+			mesh = true;
 			break;
 		default:
 			break;
@@ -2763,17 +2935,29 @@ __ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx, u8 data_offset)
 	ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
 				 rx->sdata->vif.type,
 				 rx->local->hw.extra_tx_headroom,
-				 check_da, check_sa);
+				 check_da, check_sa, mesh);
 
 	while (!skb_queue_empty(&frame_list)) {
 		rx->skb = __skb_dequeue(&frame_list);
 
-		if (!ieee80211_frame_allowed(rx, fc)) {
-			dev_kfree_skb(rx->skb);
+		res = ieee80211_rx_mesh_data(rx->sdata, rx->sta, rx->skb);
+		switch (res) {
+		case RX_QUEUED:
 			continue;
+		case RX_CONTINUE:
+			break;
+		default:
+			goto free;
 		}
 
+		if (!ieee80211_frame_allowed(rx, fc))
+			goto free;
+
 		ieee80211_deliver_skb(rx);
+		continue;
+
+free:
+		dev_kfree_skb(rx->skb);
 	}
 
 	return RX_QUEUED;
@@ -2806,6 +2990,8 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
 			if (!rx->sdata->u.mgd.use_4addr)
 				return RX_DROP_UNUSABLE;
 			break;
+		case NL80211_IFTYPE_MESH_POINT:
+			break;
 		default:
 			return RX_DROP_UNUSABLE;
 		}
@@ -2834,155 +3020,6 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
 	return __ieee80211_rx_h_amsdu(rx, 0);
 }
 
-#ifdef CONFIG_MAC80211_MESH
-static ieee80211_rx_result
-ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
-{
-	struct ieee80211_hdr *fwd_hdr, *hdr;
-	struct ieee80211_tx_info *info;
-	struct ieee80211s_hdr *mesh_hdr;
-	struct sk_buff *skb = rx->skb, *fwd_skb;
-	struct ieee80211_local *local = rx->local;
-	struct ieee80211_sub_if_data *sdata = rx->sdata;
-	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
-	u16 ac, q, hdrlen;
-	int tailroom = 0;
-
-	hdr = (struct ieee80211_hdr *) skb->data;
-	hdrlen = ieee80211_hdrlen(hdr->frame_control);
-
-	/* make sure fixed part of mesh header is there, also checks skb len */
-	if (!pskb_may_pull(rx->skb, hdrlen + 6))
-		return RX_DROP_MONITOR;
-
-	mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
-
-	/* make sure full mesh header is there, also checks skb len */
-	if (!pskb_may_pull(rx->skb,
-			   hdrlen + ieee80211_get_mesh_hdrlen(mesh_hdr)))
-		return RX_DROP_MONITOR;
-
-	/* reload pointers */
-	hdr = (struct ieee80211_hdr *) skb->data;
-	mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
-
-	if (ieee80211_drop_unencrypted(rx, hdr->frame_control)) {
-		int offset = hdrlen + ieee80211_get_mesh_hdrlen(mesh_hdr) +
-			     sizeof(rfc1042_header);
-		__be16 ethertype;
-
-		if (!ether_addr_equal(hdr->addr1, rx->sdata->vif.addr) ||
-		    skb_copy_bits(rx->skb, offset, &ethertype, 2) != 0 ||
-		    ethertype != rx->sdata->control_port_protocol)
-			return RX_DROP_MONITOR;
-	}
-
-	/* frame is in RMC, don't forward */
-	if (ieee80211_is_data(hdr->frame_control) &&
-	    is_multicast_ether_addr(hdr->addr1) &&
-	    mesh_rmc_check(rx->sdata, hdr->addr3, mesh_hdr))
-		return RX_DROP_MONITOR;
-
-	if (!ieee80211_is_data(hdr->frame_control))
-		return RX_CONTINUE;
-
-	if (!mesh_hdr->ttl)
-		return RX_DROP_MONITOR;
-
-	if (mesh_hdr->flags & MESH_FLAGS_AE) {
-		struct mesh_path *mppath;
-		char *proxied_addr;
-		char *mpp_addr;
-
-		if (is_multicast_ether_addr(hdr->addr1)) {
-			mpp_addr = hdr->addr3;
-			proxied_addr = mesh_hdr->eaddr1;
-		} else if ((mesh_hdr->flags & MESH_FLAGS_AE) ==
-			    MESH_FLAGS_AE_A5_A6) {
-			/* has_a4 already checked in ieee80211_rx_mesh_check */
-			mpp_addr = hdr->addr4;
-			proxied_addr = mesh_hdr->eaddr2;
-		} else {
-			return RX_DROP_MONITOR;
-		}
-
-		rcu_read_lock();
-		mppath = mpp_path_lookup(sdata, proxied_addr);
-		if (!mppath) {
-			mpp_path_add(sdata, proxied_addr, mpp_addr);
-		} else {
-			spin_lock_bh(&mppath->state_lock);
-			if (!ether_addr_equal(mppath->mpp, mpp_addr))
-				memcpy(mppath->mpp, mpp_addr, ETH_ALEN);
-			mppath->exp_time = jiffies;
-			spin_unlock_bh(&mppath->state_lock);
-		}
-		rcu_read_unlock();
-	}
-
-	/* Frame has reached destination.  Don't forward */
-	if (!is_multicast_ether_addr(hdr->addr1) &&
-	    ether_addr_equal(sdata->vif.addr, hdr->addr3))
-		return RX_CONTINUE;
-
-	ac = ieee802_1d_to_ac[skb->priority];
-	skb_set_queue_mapping(skb, ac);
-
-	if (!--mesh_hdr->ttl) {
-		if (!is_multicast_ether_addr(hdr->addr1))
-			IEEE80211_IFSTA_MESH_CTR_INC(ifmsh,
-						     dropped_frames_ttl);
-		goto out;
-	}
-
-	if (!ifmsh->mshcfg.dot11MeshForwarding)
-		goto out;
-
-	if (sdata->crypto_tx_tailroom_needed_cnt)
-		tailroom = IEEE80211_ENCRYPT_TAILROOM;
-
-	fwd_skb = skb_copy_expand(skb, local->tx_headroom +
-				       IEEE80211_ENCRYPT_HEADROOM,
-				  tailroom, GFP_ATOMIC);
-	if (!fwd_skb)
-		goto out;
-
-	fwd_skb->dev = sdata->dev;
-	fwd_hdr =  (struct ieee80211_hdr *) fwd_skb->data;
-	fwd_hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_RETRY);
-	info = IEEE80211_SKB_CB(fwd_skb);
-	memset(info, 0, sizeof(*info));
-	info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
-	info->control.vif = &rx->sdata->vif;
-	info->control.jiffies = jiffies;
-	if (is_multicast_ether_addr(fwd_hdr->addr1)) {
-		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_mcast);
-		memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
-		/* update power mode indication when forwarding */
-		ieee80211_mps_set_frame_flags(sdata, NULL, fwd_hdr);
-	} else if (!mesh_nexthop_lookup(sdata, fwd_skb)) {
-		/* mesh power mode flags updated in mesh_nexthop_lookup */
-		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_unicast);
-	} else {
-		/* unable to resolve next hop */
-		mesh_path_error_tx(sdata, ifmsh->mshcfg.element_ttl,
-				   fwd_hdr->addr3, 0,
-				   WLAN_REASON_MESH_PATH_NOFORWARD,
-				   fwd_hdr->addr2);
-		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_no_route);
-		kfree_skb(fwd_skb);
-		return RX_DROP_MONITOR;
-	}
-
-	IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_frames);
-	ieee80211_add_pending_skb(local, fwd_skb);
- out:
-	if (is_multicast_ether_addr(hdr->addr1))
-		return RX_CONTINUE;
-	return RX_DROP_MONITOR;
-}
-#endif
-
 static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
 {
@@ -2991,6 +3028,7 @@ ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
 	struct net_device *dev = sdata->dev;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 	__le16 fc = hdr->frame_control;
+	static ieee80211_rx_result res;
 	bool port_control;
 	int err;
 
@@ -3017,6 +3055,10 @@ ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
 	if (unlikely(err))
 		return RX_DROP_UNUSABLE;
 
+	res = ieee80211_rx_mesh_data(rx->sdata, rx->sta, rx->skb);
+	if (res != RX_CONTINUE)
+		return res;
+
 	if (!ieee80211_frame_allowed(rx, fc))
 		return RX_DROP_MONITOR;
 
@@ -3987,10 +4029,6 @@ static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx,
 		CALL_RXH(ieee80211_rx_h_defragment);
 		CALL_RXH(ieee80211_rx_h_michael_mic_verify);
 		/* must be after MMIC verify so header is counted in MPDU mic */
-#ifdef CONFIG_MAC80211_MESH
-		if (ieee80211_vif_is_mesh(&rx->sdata->vif))
-			CALL_RXH(ieee80211_rx_h_mesh_fwding);
-#endif
 		CALL_RXH(ieee80211_rx_h_amsdu);
 		CALL_RXH(ieee80211_rx_h_data);
 
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 4498807b8b70..954dd0f311b9 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -542,7 +542,7 @@ unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 }
 EXPORT_SYMBOL(ieee80211_get_mesh_hdrlen);
 
-static bool ieee80211_get_8023_tunnel_proto(const void *hdr, __be16 *proto)
+bool ieee80211_get_8023_tunnel_proto(const void *hdr, __be16 *proto)
 {
 	const __be16 *hdr_proto = hdr + ETH_ALEN;
 
@@ -556,6 +556,49 @@ static bool ieee80211_get_8023_tunnel_proto(const void *hdr, __be16 *proto)
 
 	return true;
 }
+EXPORT_SYMBOL(ieee80211_get_8023_tunnel_proto);
+
+int ieee80211_strip_8023_mesh_hdr(struct sk_buff *skb)
+{
+	const void *mesh_addr;
+	struct {
+		struct ethhdr eth;
+		u8 flags;
+	} payload;
+	int hdrlen;
+	int ret;
+
+	ret = skb_copy_bits(skb, 0, &payload, sizeof(payload));
+	if (ret)
+		return ret;
+
+	hdrlen = sizeof(payload.eth) + __ieee80211_get_mesh_hdrlen(payload.flags);
+
+	if (likely(pskb_may_pull(skb, hdrlen + 8) &&
+		   ieee80211_get_8023_tunnel_proto(skb->data + hdrlen,
+						   &payload.eth.h_proto)))
+		hdrlen += ETH_ALEN + 2;
+	else if (!pskb_may_pull(skb, hdrlen))
+		return -EINVAL;
+
+	mesh_addr = skb->data + sizeof(payload.eth) + ETH_ALEN;
+	switch (payload.flags & MESH_FLAGS_AE) {
+	case MESH_FLAGS_AE_A4:
+		memcpy(&payload.eth.h_source, mesh_addr, ETH_ALEN);
+		break;
+	case MESH_FLAGS_AE_A5_A6:
+		memcpy(&payload.eth.h_dest, mesh_addr, 2 * ETH_ALEN);
+		break;
+	default:
+		break;
+	}
+
+	pskb_pull(skb, hdrlen - sizeof(payload.eth));
+	memcpy(skb->data, &payload.eth, sizeof(payload.eth));
+
+	return 0;
+}
+EXPORT_SYMBOL(ieee80211_strip_8023_mesh_hdr);
 
 int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
 				  const u8 *addr, enum nl80211_iftype iftype,
@@ -568,7 +611,6 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
 	} payload;
 	struct ethhdr tmp;
 	u16 hdrlen;
-	u8 mesh_flags = 0;
 
 	if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
 		return -1;
@@ -589,12 +631,6 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
 	memcpy(tmp.h_dest, ieee80211_get_DA(hdr), ETH_ALEN);
 	memcpy(tmp.h_source, ieee80211_get_SA(hdr), ETH_ALEN);
 
-	if (iftype == NL80211_IFTYPE_MESH_POINT &&
-	    skb_copy_bits(skb, hdrlen, &mesh_flags, 1) < 0)
-		return -1;
-
-	mesh_flags &= MESH_FLAGS_AE;
-
 	switch (hdr->frame_control &
 		cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
 	case cpu_to_le16(IEEE80211_FCTL_TODS):
@@ -608,17 +644,6 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
 			     iftype != NL80211_IFTYPE_AP_VLAN &&
 			     iftype != NL80211_IFTYPE_STATION))
 			return -1;
-		if (iftype == NL80211_IFTYPE_MESH_POINT) {
-			if (mesh_flags == MESH_FLAGS_AE_A4)
-				return -1;
-			if (mesh_flags == MESH_FLAGS_AE_A5_A6 &&
-			    skb_copy_bits(skb, hdrlen +
-					  offsetof(struct ieee80211s_hdr, eaddr1),
-					  tmp.h_dest, 2 * ETH_ALEN) < 0)
-				return -1;
-
-			hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
-		}
 		break;
 	case cpu_to_le16(IEEE80211_FCTL_FROMDS):
 		if ((iftype != NL80211_IFTYPE_STATION &&
@@ -627,16 +652,6 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
 		    (is_multicast_ether_addr(tmp.h_dest) &&
 		     ether_addr_equal(tmp.h_source, addr)))
 			return -1;
-		if (iftype == NL80211_IFTYPE_MESH_POINT) {
-			if (mesh_flags == MESH_FLAGS_AE_A5_A6)
-				return -1;
-			if (mesh_flags == MESH_FLAGS_AE_A4 &&
-			    skb_copy_bits(skb, hdrlen +
-					  offsetof(struct ieee80211s_hdr, eaddr1),
-					  tmp.h_source, ETH_ALEN) < 0)
-				return -1;
-			hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
-		}
 		break;
 	case cpu_to_le16(0):
 		if (iftype != NL80211_IFTYPE_ADHOC &&
@@ -646,7 +661,7 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr,
 		break;
 	}
 
-	if (likely(!is_amsdu &&
+	if (likely(!is_amsdu && iftype != NL80211_IFTYPE_MESH_POINT &&
 		   skb_copy_bits(skb, hdrlen, &payload, sizeof(payload)) == 0 &&
 		   ieee80211_get_8023_tunnel_proto(&payload, &tmp.h_proto))) {
 		/* remove RFC1042 or Bridge-Tunnel encapsulation */
@@ -722,7 +737,8 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct sk_buff *frame,
 
 static struct sk_buff *
 __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
-		       int offset, int len, bool reuse_frag)
+		       int offset, int len, bool reuse_frag,
+		       int min_len)
 {
 	struct sk_buff *frame;
 	int cur_len = len;
@@ -736,7 +752,7 @@ __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
 	 * in the stack later.
 	 */
 	if (reuse_frag)
-		cur_len = min_t(int, len, 32);
+		cur_len = min_t(int, len, min_len);
 
 	/*
 	 * Allocate and reserve two bytes more for payload
@@ -746,6 +762,7 @@ __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
 	if (!frame)
 		return NULL;
 
+	frame->priority = skb->priority;
 	skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2);
 	skb_copy_bits(skb, offset, skb_put(frame, cur_len), cur_len);
 
@@ -762,23 +779,37 @@ __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
 void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
 			      const u8 *addr, enum nl80211_iftype iftype,
 			      const unsigned int extra_headroom,
-			      const u8 *check_da, const u8 *check_sa)
+			      const u8 *check_da, const u8 *check_sa,
+			      bool mesh_control)
 {
 	unsigned int hlen = ALIGN(extra_headroom, 4);
 	struct sk_buff *frame = NULL;
 	int offset = 0, remaining;
-	struct ethhdr eth;
+	struct {
+		struct ethhdr eth;
+		uint8_t flags;
+	} hdr;
 	bool reuse_frag = skb->head_frag && !skb_has_frag_list(skb);
 	bool reuse_skb = false;
 	bool last = false;
+	int copy_len = sizeof(hdr.eth);
+
+	if (iftype == NL80211_IFTYPE_MESH_POINT)
+		copy_len = sizeof(hdr);
 
 	while (!last) {
 		unsigned int subframe_len;
-		int len;
+		int len, mesh_len = 0;
 		u8 padding;
 
-		skb_copy_bits(skb, offset, &eth, sizeof(eth));
-		len = ntohs(eth.h_proto);
+		skb_copy_bits(skb, offset, &hdr, copy_len);
+		if (iftype == NL80211_IFTYPE_MESH_POINT)
+			mesh_len = __ieee80211_get_mesh_hdrlen(hdr.flags);
+		if (mesh_control)
+			len = le16_to_cpu(*(__le16 *)&hdr.eth.h_proto) + mesh_len;
+		else
+			len = ntohs(hdr.eth.h_proto);
+
 		subframe_len = sizeof(struct ethhdr) + len;
 		padding = (4 - subframe_len) & 0x3;
 
@@ -787,16 +818,16 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
 		if (subframe_len > remaining)
 			goto purge;
 		/* mitigate A-MSDU aggregation injection attacks */
-		if (ether_addr_equal(eth.h_dest, rfc1042_header))
+		if (ether_addr_equal(hdr.eth.h_dest, rfc1042_header))
 			goto purge;
 
 		offset += sizeof(struct ethhdr);
 		last = remaining <= subframe_len + padding;
 
 		/* FIXME: should we really accept multicast DA? */
-		if ((check_da && !is_multicast_ether_addr(eth.h_dest) &&
-		     !ether_addr_equal(check_da, eth.h_dest)) ||
-		    (check_sa && !ether_addr_equal(check_sa, eth.h_source))) {
+		if ((check_da && !is_multicast_ether_addr(hdr.eth.h_dest) &&
+		     !ether_addr_equal(check_da, hdr.eth.h_dest)) ||
+		    (check_sa && !ether_addr_equal(check_sa, hdr.eth.h_source))) {
 			offset += len + padding;
 			continue;
 		}
@@ -808,7 +839,7 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
 			reuse_skb = true;
 		} else {
 			frame = __ieee80211_amsdu_copy(skb, hlen, offset, len,
-						       reuse_frag);
+						       reuse_frag, 32 + mesh_len);
 			if (!frame)
 				goto purge;
 
@@ -819,10 +850,11 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
 		frame->dev = skb->dev;
 		frame->priority = skb->priority;
 
-		if (likely(ieee80211_get_8023_tunnel_proto(frame->data, &eth.h_proto)))
+		if (likely(iftype != NL80211_IFTYPE_MESH_POINT &&
+			   ieee80211_get_8023_tunnel_proto(frame->data, &hdr.eth.h_proto)))
 			skb_pull(frame, ETH_ALEN + 2);
 
-		memcpy(skb_push(frame, sizeof(eth)), &eth, sizeof(eth));
+		memcpy(skb_push(frame, sizeof(hdr.eth)), &hdr.eth, sizeof(hdr.eth));
 		__skb_queue_tail(list, frame);
 	}
 
-- 
2.39.0