staging: wfx: simplify handling of encrypted frames

We don't want mac80211 try to check MMIC and other security mechanisms.
So, the driver remove all the data related to the encryption (IV, ICV,
MMIC).

However, enabling RX_FLAG_PN_VALIDATED is sufficient for that.

So, drop the useless function wfx_drop_encrypt_data() and enable
RX_FLAG_PN_VALIDATED.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200701150707.222985-11-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/data_rx.c

@@ -13,57 +13,6 @@
 #include "bh.h"
 #include "sta.h"
 
-static int wfx_drop_encrypt_data(struct wfx_dev *wdev,
-				 const struct hif_ind_rx *arg,
-				 struct sk_buff *skb)
-{
-	struct ieee80211_hdr *frame = (struct ieee80211_hdr *)skb->data;
-	size_t hdrlen = ieee80211_hdrlen(frame->frame_control);
-	size_t iv_len, icv_len;
-
-	/* Oops... There is no fast way to ask mac80211 about
-	 * IV/ICV lengths. Even defineas are not exposed.
-	 */
-	switch (arg->rx_flags.encryp) {
-	case HIF_RI_FLAGS_WEP_ENCRYPTED:
-		iv_len = 4 /* WEP_IV_LEN */;
-		icv_len = 4 /* WEP_ICV_LEN */;
-		break;
-	case HIF_RI_FLAGS_TKIP_ENCRYPTED:
-		iv_len = 8 /* TKIP_IV_LEN */;
-		icv_len = 4 /* TKIP_ICV_LEN */
-			+ 8 /*MICHAEL_MIC_LEN*/;
-		break;
-	case HIF_RI_FLAGS_AES_ENCRYPTED:
-		iv_len = 8 /* CCMP_HDR_LEN */;
-		icv_len = 8 /* CCMP_MIC_LEN */;
-		break;
-	case HIF_RI_FLAGS_WAPI_ENCRYPTED:
-		iv_len = 18 /* WAPI_HDR_LEN */;
-		icv_len = 16 /* WAPI_MIC_LEN */;
-		break;
-	default:
-		dev_err(wdev->dev, "unknown encryption type %d\n",
-			arg->rx_flags.encryp);
-		return -EIO;
-	}
-
-	/* Firmware strips ICV in case of MIC failure. */
-	if (arg->status == HIF_STATUS_RX_FAIL_MIC)
-		icv_len = 0;
-
-	if (skb->len < hdrlen + iv_len + icv_len) {
-		dev_warn(wdev->dev, "malformed SDU received\n");
-		return -EIO;
-	}
-
-	/* Remove IV, ICV and MIC */
-	skb_trim(skb, skb->len - icv_len);
-	memmove(skb->data + iv_len, skb->data, hdrlen);
-	skb_pull(skb, iv_len);
-	return 0;
-}
-
 void wfx_rx_cb(struct wfx_vif *wvif,
 	       const struct hif_ind_rx *arg, struct sk_buff *skb)
 {
@@ -103,13 +52,8 @@ void wfx_rx_cb(struct wfx_vif *wvif,
 	hdr->signal = arg->rcpi_rssi / 2 - 110;
 	hdr->antenna = 0;
 
-	if (arg->rx_flags.encryp) {
-		if (wfx_drop_encrypt_data(wvif->wdev, arg, skb))
-			goto drop;
-		hdr->flag |= RX_FLAG_DECRYPTED | RX_FLAG_IV_STRIPPED;
-		if (arg->rx_flags.encryp == HIF_RI_FLAGS_TKIP_ENCRYPTED)
-			hdr->flag |= RX_FLAG_MMIC_STRIPPED;
-	}
+	if (arg->rx_flags.encryp)
+		hdr->flag |= RX_FLAG_DECRYPTED | RX_FLAG_PN_VALIDATED;
 
 	/* Filter block ACK negotiation: fully controlled by firmware */
 	if (ieee80211_is_action(frame->frame_control) &&