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>

2 files changed, 89 insertions, 3 deletions

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index 423f69015e3e..bd361c19557d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -249,6 +249,82 @@ static void mt7615_mac_fill_tm_rx(struct mt7615_phy *phy, __le32 *rxv)
 #endif
 }
 
+/* The HW does not translate the mac header to 802.3 for mesh point */
+static int mt7615_reverse_frag0_hdr_trans(struct sk_buff *skb, u16 hdr_gap)
+{
+	struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
+	struct mt7615_sta *msta = (struct mt7615_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_RXD1_NORMAL_ADDR_TYPE, le32_to_cpu(rxd[1])) !=
+	    MT_RXD1_NORMAL_U2M)
+		return -EINVAL;
+
+	if (!(le32_to_cpu(rxd[0]) & MT_RXD0_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_RXD4_FRAME_CONTROL, rxd[4]);
+	hdr.seq_ctrl = FIELD_GET(MT_RXD6_SEQ_CTRL, rxd[6]);
+	qos_ctrl = FIELD_GET(MT_RXD6_QOS_CTL, rxd[6]);
+	ht_ctrl = FIELD_GET(MT_RXD7_HT_CONTROL, rxd[7]);
+
+	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 mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
 {
 	struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
@@ -263,6 +339,7 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
 	u32 rxd2 = le32_to_cpu(rxd[2]);
 	u32 csum_mask = MT_RXD0_NORMAL_IP_SUM | MT_RXD0_NORMAL_UDP_TCP_SUM;
 	bool unicast, hdr_trans, remove_pad, insert_ccmp_hdr = false;
+	u16 hdr_gap;
 	int phy_idx;
 	int i, idx;
 	u8 chfreq, amsdu_info, qos_ctl = 0;
@@ -503,14 +580,21 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
 			return -EINVAL;
 	}
 
-	skb_pull(skb, (u8 *)rxd - skb->data + 2 * remove_pad);
-
 	amsdu_info = FIELD_GET(MT_RXD1_NORMAL_PAYLOAD_FORMAT, rxd1);
 	status->amsdu = !!amsdu_info;
 	if (status->amsdu) {
 		status->first_amsdu = amsdu_info == MT_RXD1_FIRST_AMSDU_FRAME;
 		status->last_amsdu = amsdu_info == MT_RXD1_LAST_AMSDU_FRAME;
-		if (!hdr_trans) {
+	}
+
+	hdr_gap = (u8 *)rxd - skb->data + 2 * remove_pad;
+	if (hdr_trans && ieee80211_has_morefrags(fc)) {
+		if (mt7615_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);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.h b/drivers/net/wireless/mediatek/mt76/mt7615/mac.h
index 46f283eb8d0f..e241c613091c 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.h
@@ -86,6 +86,8 @@ enum rx_pkt_type {
 #define MT_RXD6_SEQ_CTRL		GENMASK(15, 0)
 #define MT_RXD6_QOS_CTL			GENMASK(31, 16)
 
+#define MT_RXD7_HT_CONTROL		GENMASK(31, 0)
+
 #define MT_RXV1_ACID_DET_H		BIT(31)
 #define MT_RXV1_ACID_DET_L		BIT(30)
 #define MT_RXV1_VHTA2_B8_B3		GENMASK(29, 24)