mt76: reverse the first fragmented frame to 802.11

The HW can apply header translation to first fragmented frame, and
ramaining fragmented frame can only keep 802.11 format. Check and
reverse the first fragmented frame to  802.11 format to make sure
them can be defragmented by mac80211.

Signed-off-by: Xing Song <xing.song@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

1 files changed, 87 insertions, 3 deletions

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index db3302b1576a..d7ab41773035 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -395,6 +395,82 @@ mt7921_mac_assoc_rssi(struct mt7921_dev *dev, struct sk_buff *skb)
 		mt7921_mac_rssi_iter, skb);
 }
 
+/* The HW does not translate the mac header to 802.3 for mesh point */
+static int mt7921_reverse_frag0_hdr_trans(struct sk_buff *skb, u16 hdr_gap)
+{
+	struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
+	struct mt7921_sta *msta = (struct mt7921_sta *)status->wcid;
+	struct ieee80211_sta *sta;
+	struct ieee80211_vif *vif;
+	struct ieee80211_hdr hdr;
+	struct ethhdr eth_hdr;
+	__le32 *rxd = (__le32 *)skb->data;
+	__le32 qos_ctrl, ht_ctrl;
+
+	if (FIELD_GET(MT_RXD3_NORMAL_ADDR_TYPE, le32_to_cpu(rxd[3])) !=
+	    MT_RXD3_NORMAL_U2M)
+		return -EINVAL;
+
+	if (!(le32_to_cpu(rxd[1]) & MT_RXD1_NORMAL_GROUP_4))
+		return -EINVAL;
+
+	if (!msta || !msta->vif)
+		return -EINVAL;
+
+	sta = container_of((void *)msta, struct ieee80211_sta, drv_priv);
+	vif = container_of((void *)msta->vif, struct ieee80211_vif, drv_priv);
+
+	/* store the info from RXD and ethhdr to avoid being overridden */
+	memcpy(&eth_hdr, skb->data + hdr_gap, sizeof(eth_hdr));
+	hdr.frame_control = FIELD_GET(MT_RXD6_FRAME_CONTROL, rxd[6]);
+	hdr.seq_ctrl = FIELD_GET(MT_RXD8_SEQ_CTRL, rxd[8]);
+	qos_ctrl = FIELD_GET(MT_RXD8_QOS_CTL, rxd[8]);
+	ht_ctrl = FIELD_GET(MT_RXD9_HT_CONTROL, rxd[9]);
+
+	hdr.duration_id = 0;
+	ether_addr_copy(hdr.addr1, vif->addr);
+	ether_addr_copy(hdr.addr2, sta->addr);
+	switch (le16_to_cpu(hdr.frame_control) &
+		(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
+	case 0:
+		ether_addr_copy(hdr.addr3, vif->bss_conf.bssid);
+		break;
+	case IEEE80211_FCTL_FROMDS:
+		ether_addr_copy(hdr.addr3, eth_hdr.h_source);
+		break;
+	case IEEE80211_FCTL_TODS:
+		ether_addr_copy(hdr.addr3, eth_hdr.h_dest);
+		break;
+	case IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS:
+		ether_addr_copy(hdr.addr3, eth_hdr.h_dest);
+		ether_addr_copy(hdr.addr4, eth_hdr.h_source);
+		break;
+	default:
+		break;
+	}
+
+	skb_pull(skb, hdr_gap + sizeof(struct ethhdr) - 2);
+	if (eth_hdr.h_proto == htons(ETH_P_AARP) ||
+	    eth_hdr.h_proto == htons(ETH_P_IPX))
+		ether_addr_copy(skb_push(skb, ETH_ALEN), bridge_tunnel_header);
+	else if (eth_hdr.h_proto >= htons(ETH_P_802_3_MIN))
+		ether_addr_copy(skb_push(skb, ETH_ALEN), rfc1042_header);
+	else
+		skb_pull(skb, 2);
+
+	if (ieee80211_has_order(hdr.frame_control))
+		memcpy(skb_push(skb, 2), &ht_ctrl, 2);
+	if (ieee80211_is_data_qos(hdr.frame_control))
+		memcpy(skb_push(skb, 2), &qos_ctrl, 2);
+	if (ieee80211_has_a4(hdr.frame_control))
+		memcpy(skb_push(skb, sizeof(hdr)), &hdr, sizeof(hdr));
+	else
+		memcpy(skb_push(skb, sizeof(hdr) - 6), &hdr, sizeof(hdr) - 6);
+
+	status->flag &= ~(RX_FLAG_RADIOTAP_HE | RX_FLAG_RADIOTAP_HE_MU);
+	return 0;
+}
+
 static int
 mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
 {
@@ -402,6 +478,7 @@ mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
 	struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
 	bool hdr_trans, unicast, insert_ccmp_hdr = false;
 	u8 chfreq, qos_ctl = 0, remove_pad, amsdu_info;
+	u16 hdr_gap;
 	__le32 *rxv = NULL, *rxd = (__le32 *)skb->data;
 	struct mt76_phy *mphy = &dev->mt76.phy;
 	struct mt7921_phy *phy = &dev->phy;
@@ -668,14 +745,21 @@ mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
 		}
 	}
 
-	skb_pull(skb, (u8 *)rxd - skb->data + 2 * remove_pad);
-
 	amsdu_info = FIELD_GET(MT_RXD4_NORMAL_PAYLOAD_FORMAT, rxd4);
 	status->amsdu = !!amsdu_info;
 	if (status->amsdu) {
 		status->first_amsdu = amsdu_info == MT_RXD4_FIRST_AMSDU_FRAME;
 		status->last_amsdu = amsdu_info == MT_RXD4_LAST_AMSDU_FRAME;
-		if (!hdr_trans) {
+	}
+
+	hdr_gap = (u8 *)rxd - skb->data + 2 * remove_pad;
+	if (hdr_trans && ieee80211_has_morefrags(fc)) {
+		if (mt7921_reverse_frag0_hdr_trans(skb, hdr_gap))
+			return -EINVAL;
+		hdr_trans = false;
+	} else {
+		skb_pull(skb, hdr_gap);
+		if (!hdr_trans && status->amsdu) {
 			memmove(skb->data + 2, skb->data,
 				ieee80211_get_hdrlen_from_skb(skb));
 			skb_pull(skb, 2);