drivers/staging/wfx/data_rx.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Datapath implementation.
 *
 * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
 * Copyright (c) 2010, ST-Ericsson
 */
#include <linux/etherdevice.h>
#include <net/mac80211.h>

#include "data_rx.h"
#include "wfx.h"
#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_MICFAILURE)
		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)
{
	struct ieee80211_rx_status *hdr = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *frame = (struct ieee80211_hdr *)skb->data;
	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)skb->data;

	memset(hdr, 0, sizeof(*hdr));

	// FIXME: Why do we drop these frames?
	if (!arg->rcpi_rssi &&
	    (ieee80211_is_probe_resp(frame->frame_control) ||
	     ieee80211_is_beacon(frame->frame_control)))
		goto drop;

	if (arg->status == HIF_STATUS_MICFAILURE)
		hdr->flag |= RX_FLAG_MMIC_ERROR;
	else if (arg->status)
		goto drop;

	if (skb->len < sizeof(struct ieee80211_pspoll)) {
		dev_warn(wvif->wdev->dev, "malformed SDU received\n");
		goto drop;
	}

	hdr->band = NL80211_BAND_2GHZ;
	hdr->freq = ieee80211_channel_to_frequency(arg->channel_number,
						   hdr->band);

	if (arg->rxed_rate >= 14) {
		hdr->encoding = RX_ENC_HT;
		hdr->rate_idx = arg->rxed_rate - 14;
	} else if (arg->rxed_rate >= 4) {
		hdr->rate_idx = arg->rxed_rate - 2;
	} else {
		hdr->rate_idx = arg->rxed_rate;
	}

	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;
	}

	/* Filter block ACK negotiation: fully controlled by firmware */
	if (ieee80211_is_action(frame->frame_control) &&
	    arg->rx_flags.match_uc_addr &&
	    mgmt->u.action.category == WLAN_CATEGORY_BACK)
		goto drop;
	if (ieee80211_is_beacon(frame->frame_control) &&
	    !arg->status && wvif->vif &&
	    ether_addr_equal(ieee80211_get_SA(frame),
			     wvif->vif->bss_conf.bssid)) {
		/* Disable beacon filter once we're associated... */
		if (wvif->disable_beacon_filter &&
		    (wvif->vif->bss_conf.assoc ||
		     wvif->vif->bss_conf.ibss_joined)) {
			wvif->disable_beacon_filter = false;
			schedule_work(&wvif->update_filtering_work);
		}
	}
	ieee80211_rx_irqsafe(wvif->wdev->hw, skb);

	return;

drop:
	dev_kfree_skb(skb);
}