xref: /wlan-driver/qcacld-3.0/core/dp/txrx/ol_txrx_encap.c (revision 5113495b16420b49004c444715d2daae2066e7dc)

/*
 * Copyright (c) 2012-2017, 2019 The Linux Foundation. All rights reserved.
 *
 * Permission to use, copy, modify, and/or distribute this software for
 * any purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
 * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/**
 * @file ol_txrx_encap.c
 * @brief Provide functions to encap/decap on txrx frames.
 * @details
 *  This file contains functions for data frame encap/decap:
 *  ol_tx_encap: encap outgoing data frames.
 *  ol_rx_decap: decap incoming data frames.
 */
#ifdef QCA_SUPPORT_SW_TXRX_ENCAP

#include <qdf_nbuf.h>           /* qdf_nbuf_t, etc. */
#include <cds_ieee80211_common.h>   /* ieee80211_frame */
#include <ol_txrx_internal.h>   /* TXRX_ASSERT1 */
#include <ol_txrx_encap.h>      /* struct ol_rx_decap_info_t */

static inline A_STATUS
ol_tx_copy_native_wifi_header(qdf_nbuf_t msdu,
			      uint8_t *hdsize, uint8_t *localbuf)
{
	struct ieee80211_frame *wh =
		(struct ieee80211_frame *)qdf_nbuf_data(msdu);
	if ((wh->i_fc[1] &
	     IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS) {
		*hdsize = sizeof(struct ieee80211_frame_addr4);
	} else {
		*hdsize = sizeof(struct ieee80211_frame);
	}
	if (qdf_nbuf_len(msdu) < *hdsize)
		return A_ERROR;

	qdf_mem_copy(localbuf, wh, *hdsize);
	return A_OK;
}

static inline A_STATUS
ol_tx_encap_from_native_wifi(struct ol_txrx_vdev_t *vdev,
			     struct ol_tx_desc_t *tx_desc,
			     qdf_nbuf_t msdu,
			     struct ol_txrx_msdu_info_t *tx_msdu_info)
{
	uint8_t localbuf[sizeof(struct ieee80211_qosframe_htc_addr4)];
	struct ieee80211_frame *wh;
	uint8_t hdsize, new_hdsize;
	struct ieee80211_qoscntl *qos_cntl;
	struct ol_txrx_peer_t *peer;

	if (tx_msdu_info->htt.info.frame_type != htt_frm_type_data)
		return A_OK;

	peer = tx_msdu_info->peer;
	/*
	 * for unicast,the peer should not be NULL.
	 * for multicast, the peer is AP.
	 */
	if (tx_msdu_info->htt.info.is_unicast && peer->qos_capable) {
		if (A_OK !=
		    ol_tx_copy_native_wifi_header(msdu, &hdsize, localbuf))
			return A_ERROR;
		wh = (struct ieee80211_frame *)localbuf;

		/*add qos cntl */
		qos_cntl = (struct ieee80211_qoscntl *)(localbuf + hdsize);
		qos_cntl->i_qos[0] =
			tx_msdu_info->htt.info.ext_tid & IEEE80211_QOS_TID;

#ifdef NEVERDEFINED
		if (wmmParam[ac].wmep_noackPolicy)
			qos_cntl->i_qos[0] |= 1 << IEEE80211_QOS_ACKPOLICY_S;
#endif

		qos_cntl->i_qos[1] = 0;
		wh->i_fc[0] |= QDF_IEEE80211_FC0_SUBTYPE_QOS;
		/* count for qos field */
		new_hdsize =
			hdsize + sizeof(struct ieee80211_qosframe) -
			sizeof(struct ieee80211_frame);

		/*add ht control field if needed */

		/* copy new hd to bd */
		qdf_mem_copy((void *)
			     htt_tx_desc_mpdu_header(tx_desc->htt_tx_desc,
						     new_hdsize), localbuf,
			     new_hdsize);
		qdf_nbuf_pull_head(msdu, hdsize);
		tx_msdu_info->htt.info.l3_hdr_offset = new_hdsize;
		tx_desc->orig_l2_hdr_bytes = hdsize;
	}
	/* Set Protected Frame bit in MAC header */
	if (vdev->pdev->sw_pf_proc_enable
	    && tx_msdu_info->htt.action.do_encrypt) {
		if (tx_desc->orig_l2_hdr_bytes) {
			wh = (struct ieee80211_frame *)
			     htt_tx_desc_mpdu_header(tx_desc->htt_tx_desc,
						     tx_msdu_info->htt.info.
						     l3_hdr_offset);
		} else {
			if (A_OK !=
			    ol_tx_copy_native_wifi_header(msdu, &hdsize,
							  localbuf))
				return A_ERROR;
			wh = (struct ieee80211_frame *)
			     htt_tx_desc_mpdu_header(tx_desc->htt_tx_desc,
						     hdsize);
			qdf_mem_copy((void *)wh, localbuf, hdsize);
			qdf_nbuf_pull_head(msdu, hdsize);
			tx_msdu_info->htt.info.l3_hdr_offset = hdsize;
			tx_desc->orig_l2_hdr_bytes = hdsize;
		}
		wh->i_fc[1] |= IEEE80211_FC1_WEP;
	}
	return A_OK;
}

static inline A_STATUS
ol_tx_encap_from_8023(struct ol_txrx_vdev_t *vdev,
		      struct ol_tx_desc_t *tx_desc,
		      qdf_nbuf_t msdu, struct ol_txrx_msdu_info_t *tx_msdu_info)
{
	uint8_t localbuf[sizeof(struct ieee80211_qosframe_htc_addr4)
			 + sizeof(struct llc_snap_hdr_t)];
	struct llc_snap_hdr_t *llc_hdr;
	struct ethernet_hdr_t *eth_hdr;
	struct ieee80211_frame *wh;
	uint8_t hdsize, new_l2_hdsize, new_hdsize;
	struct ieee80211_qoscntl *qos_cntl;
	const uint8_t ethernet_II_llc_snap_header_prefix[] = {
		0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
	struct ol_txrx_peer_t *peer;
	uint16_t ether_type;

	if (tx_msdu_info->htt.info.frame_type != htt_frm_type_data)
		return A_OK;

	/*
	 * for unicast,the peer should not be NULL.
	 * for multicast, the peer is AP.
	 */
	peer = tx_msdu_info->peer;

	eth_hdr = (struct ethernet_hdr_t *)qdf_nbuf_data(msdu);
	hdsize = sizeof(struct ethernet_hdr_t);
	wh = (struct ieee80211_frame *)localbuf;
	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_DATA;
	*(uint16_t *) wh->i_dur = 0;
	new_hdsize = 0;

	switch (vdev->opmode) {
	case wlan_op_mode_ap:
		/* DA , BSSID , SA */
		qdf_mem_copy(wh->i_addr1, eth_hdr->dest_addr,
			     QDF_MAC_ADDR_SIZE);
		qdf_mem_copy(wh->i_addr2, &vdev->mac_addr.raw,
			     QDF_MAC_ADDR_SIZE);
		qdf_mem_copy(wh->i_addr3, eth_hdr->src_addr,
			     QDF_MAC_ADDR_SIZE);
		wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
		new_hdsize = sizeof(struct ieee80211_frame);
		break;
	case wlan_op_mode_ibss:
		/* DA, SA, BSSID */
		qdf_mem_copy(wh->i_addr1, eth_hdr->dest_addr,
			     QDF_MAC_ADDR_SIZE);
		qdf_mem_copy(wh->i_addr2, eth_hdr->src_addr,
			     QDF_MAC_ADDR_SIZE);
		/* need to check the bssid behaviour for IBSS vdev */
		qdf_mem_copy(wh->i_addr3, &vdev->mac_addr.raw,
			     QDF_MAC_ADDR_SIZE);
		wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
		new_hdsize = sizeof(struct ieee80211_frame);
		break;
	case wlan_op_mode_sta:
		/* BSSID, SA , DA */
		qdf_mem_copy(wh->i_addr1, &peer->mac_addr.raw,
			     QDF_MAC_ADDR_SIZE);
		qdf_mem_copy(wh->i_addr2, eth_hdr->src_addr,
			     QDF_MAC_ADDR_SIZE);
		qdf_mem_copy(wh->i_addr3, eth_hdr->dest_addr,
			     QDF_MAC_ADDR_SIZE);
		wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
		new_hdsize = sizeof(struct ieee80211_frame);
		break;
	case wlan_op_mode_monitor:
	default:
		return A_ERROR;
	}
	/*add qos cntl */
	if (tx_msdu_info->htt.info.is_unicast && peer->qos_capable) {
		qos_cntl = (struct ieee80211_qoscntl *)(localbuf + new_hdsize);
		qos_cntl->i_qos[0] =
			tx_msdu_info->htt.info.ext_tid & IEEE80211_QOS_TID;
		wh->i_fc[0] |= QDF_IEEE80211_FC0_SUBTYPE_QOS;
#ifdef NEVERDEFINED
		if (wmmParam[ac].wmep_noackPolicy)
			qos_cntl->i_qos[0] |= 1 << IEEE80211_QOS_ACKPOLICY_S;
#endif
		qos_cntl->i_qos[1] = 0;
		new_hdsize += sizeof(struct ieee80211_qoscntl);

		/*add ht control field if needed */
	}
	/* Set Protected Frame bit in MAC header */
	if (vdev->pdev->sw_pf_proc_enable
	    && tx_msdu_info->htt.action.do_encrypt) {
		wh->i_fc[1] |= IEEE80211_FC1_WEP;
	}
	new_l2_hdsize = new_hdsize;
	/* add llc snap if needed */
	if (vdev->pdev->sw_tx_llc_proc_enable) {
		llc_hdr = (struct llc_snap_hdr_t *)(localbuf + new_hdsize);
		ether_type =
			(eth_hdr->ethertype[0] << 8) | (eth_hdr->ethertype[1]);
		if (ether_type >= ETH_P_802_3_MIN) {
			qdf_mem_copy(llc_hdr,
				     ethernet_II_llc_snap_header_prefix,
				     sizeof
				     (ethernet_II_llc_snap_header_prefix));
			if (ether_type == ETHERTYPE_AARP
			    || ether_type == ETHERTYPE_IPX) {
				llc_hdr->org_code[2] = BTEP_SNAP_ORGCODE_2;
				/* 0xf8; bridge tunnel header */
			}
			llc_hdr->ethertype[0] = eth_hdr->ethertype[0];
			llc_hdr->ethertype[1] = eth_hdr->ethertype[1];
			new_hdsize += sizeof(struct llc_snap_hdr_t);
		} else {
			/*
			 * llc ready, and it's in payload pdu,
			 * do we need to move to BD pdu?
			 */
		}
	}
	qdf_mem_copy((void *)
		     htt_tx_desc_mpdu_header(tx_desc->htt_tx_desc,
					     new_l2_hdsize), localbuf,
		     new_hdsize);
	qdf_nbuf_pull_head(msdu, hdsize);
	tx_msdu_info->htt.info.l3_hdr_offset = new_l2_hdsize;
	tx_desc->orig_l2_hdr_bytes = hdsize;
	return A_OK;
}

A_STATUS
ol_tx_encap(struct ol_txrx_vdev_t *vdev,
	    struct ol_tx_desc_t *tx_desc,
	    qdf_nbuf_t msdu, struct ol_txrx_msdu_info_t *msdu_info)
{
	struct ol_txrx_pdev_t *pdev = vdev->pdev;

	if (pdev->frame_format == wlan_frm_fmt_native_wifi) {
		return ol_tx_encap_from_native_wifi(vdev, tx_desc, msdu,
						    msdu_info);
	} else if (pdev->frame_format == wlan_frm_fmt_802_3) {
		return ol_tx_encap_from_8023(vdev, tx_desc, msdu, msdu_info);
	}

	/* todo for other types */
	return A_ERROR;
}

static inline void
ol_rx_decap_to_native_wifi(struct ol_txrx_vdev_t *vdev,
			   qdf_nbuf_t msdu,
			   struct ol_rx_decap_info_t *info,
			   struct ethernet_hdr_t *ethr_hdr)
{
	struct ieee80211_frame_addr4 *wh;
	uint16_t hdsize;

	/*
	 * we need to remove Qos control field and HT control.
	 * MSFT: http://msdn.microsoft.com/en-us/library/windows/
	 * hardware/ff552608(v=vs.85).aspx
	 */
	wh = (struct ieee80211_frame_addr4 *)info->hdr;
	if ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) ==
	    IEEE80211_FC1_DIR_DSTODS)
		hdsize = sizeof(struct ieee80211_frame_addr4);
	else
		hdsize = sizeof(struct ieee80211_frame);

	wh = (struct ieee80211_frame_addr4 *)qdf_nbuf_push_head(msdu, hdsize);
	TXRX_ASSERT2(wh);
	TXRX_ASSERT2(hdsize <= info->hdr_len);
	qdf_mem_copy((uint8_t *) wh, info->hdr, hdsize);

	/* amsdu subfrm handling if ethr_hdr is not NULL  */
	if (ethr_hdr) {
		switch (wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) {
		case IEEE80211_FC1_DIR_NODS:
			qdf_mem_copy(wh->i_addr1, ethr_hdr->dest_addr,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(wh->i_addr2, ethr_hdr->src_addr,
				     QDF_MAC_ADDR_SIZE);
			break;
		case IEEE80211_FC1_DIR_TODS:
			qdf_mem_copy(wh->i_addr2, ethr_hdr->src_addr,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(wh->i_addr3, ethr_hdr->dest_addr,
				     QDF_MAC_ADDR_SIZE);
			break;
		case IEEE80211_FC1_DIR_FROMDS:
			qdf_mem_copy(wh->i_addr1, ethr_hdr->dest_addr,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(wh->i_addr3, ethr_hdr->src_addr,
				     QDF_MAC_ADDR_SIZE);
			break;
		case IEEE80211_FC1_DIR_DSTODS:
			qdf_mem_copy(wh->i_addr3, ethr_hdr->dest_addr,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(wh->i_addr4, ethr_hdr->src_addr,
				     QDF_MAC_ADDR_SIZE);
			break;
		}
	}
	if (IEEE80211_QOS_HAS_SEQ(wh)) {
		if (wh->i_fc[1] & IEEE80211_FC1_ORDER)
			wh->i_fc[1] &= ~IEEE80211_FC1_ORDER;
		wh->i_fc[0] &= ~QDF_IEEE80211_FC0_SUBTYPE_QOS;
	}
}

static inline void
ol_rx_decap_to_8023(struct ol_txrx_vdev_t *vdev,
		    qdf_nbuf_t msdu,
		    struct ol_rx_decap_info_t *info,
		    struct ethernet_hdr_t *ethr_hdr)
{
	struct llc_snap_hdr_t *llc_hdr;
	uint16_t ether_type;
	uint16_t l2_hdr_space;
	struct ieee80211_frame_addr4 *wh;
	uint8_t local_buf[ETHERNET_HDR_LEN];
	uint8_t *buf;

	/*
	 * populate Ethernet header,
	 * if ethr_hdr is null, rx frame is 802.11 format(HW ft disabled)
	 * if ethr_hdr is not null, rx frame is "subfrm of amsdu".
	 */
	buf = (uint8_t *) qdf_nbuf_data(msdu);
	llc_hdr = (struct llc_snap_hdr_t *)buf;
	ether_type = (llc_hdr->ethertype[0] << 8) | llc_hdr->ethertype[1];
	/* do llc remove if needed */
	l2_hdr_space = 0;
	if (IS_SNAP(llc_hdr)) {
		if (IS_BTEP(llc_hdr)) {
			/* remove llc */
			l2_hdr_space += sizeof(struct llc_snap_hdr_t);
			llc_hdr = NULL;
		} else if (IS_RFC1042(llc_hdr)) {
			if (!(ether_type == ETHERTYPE_AARP ||
			      ether_type == ETHERTYPE_IPX)) {
				/* remove llc */
				l2_hdr_space += sizeof(struct llc_snap_hdr_t);
				llc_hdr = NULL;
			}
		}
	}
	if (l2_hdr_space > ETHERNET_HDR_LEN)
		buf = qdf_nbuf_pull_head(msdu, l2_hdr_space - ETHERNET_HDR_LEN);
	else if (l2_hdr_space < ETHERNET_HDR_LEN)
		buf = qdf_nbuf_push_head(msdu, ETHERNET_HDR_LEN - l2_hdr_space);

	/* normal msdu(non-subfrm of A-MSDU) if ethr_hdr is null */
	if (!ethr_hdr) {
		/*
		 * mpdu hdr should be present in info,
		 * re-create ethr_hdr based on mpdu hdr
		 */
		TXRX_ASSERT2(info->hdr_len != 0);
		wh = (struct ieee80211_frame_addr4 *)info->hdr;
		ethr_hdr = (struct ethernet_hdr_t *)local_buf;
		switch (wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) {
		case IEEE80211_FC1_DIR_NODS:
			qdf_mem_copy(ethr_hdr->dest_addr, wh->i_addr1,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(ethr_hdr->src_addr, wh->i_addr2,
				     QDF_MAC_ADDR_SIZE);
			break;
		case IEEE80211_FC1_DIR_TODS:
			qdf_mem_copy(ethr_hdr->dest_addr, wh->i_addr3,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(ethr_hdr->src_addr, wh->i_addr2,
				     QDF_MAC_ADDR_SIZE);
			break;
		case IEEE80211_FC1_DIR_FROMDS:
			qdf_mem_copy(ethr_hdr->dest_addr, wh->i_addr1,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(ethr_hdr->src_addr, wh->i_addr3,
				     QDF_MAC_ADDR_SIZE);
			break;
		case IEEE80211_FC1_DIR_DSTODS:
			qdf_mem_copy(ethr_hdr->dest_addr, wh->i_addr3,
				     QDF_MAC_ADDR_SIZE);
			qdf_mem_copy(ethr_hdr->src_addr, wh->i_addr4,
				     QDF_MAC_ADDR_SIZE);
			break;
		}
	}
	if (!llc_hdr) {
		ethr_hdr->ethertype[0] = (ether_type >> 8) & 0xff;
		ethr_hdr->ethertype[1] = (ether_type) & 0xff;
	} else {
		uint32_t pktlen =
			qdf_nbuf_len(msdu) - sizeof(ethr_hdr->ethertype);
		TXRX_ASSERT2(pktlen <= ETHERNET_MTU);
		ether_type = (uint16_t) pktlen;
		ether_type = qdf_nbuf_len(msdu) - sizeof(struct ethernet_hdr_t);
		ethr_hdr->ethertype[0] = (ether_type >> 8) & 0xff;
		ethr_hdr->ethertype[1] = (ether_type) & 0xff;
	}
	qdf_mem_copy(buf, ethr_hdr, ETHERNET_HDR_LEN);
}

static inline A_STATUS
ol_rx_decap_subfrm_amsdu(struct ol_txrx_vdev_t *vdev,
			 qdf_nbuf_t msdu, struct ol_rx_decap_info_t *info)
{
	struct ol_txrx_pdev_t *pdev = vdev->pdev;
	uint8_t *subfrm_hdr;
	uint8_t localbuf[ETHERNET_HDR_LEN];
	struct ethernet_hdr_t *ether_hdr = (struct ethernet_hdr_t *)localbuf;

	subfrm_hdr = (uint8_t *) qdf_nbuf_data(msdu);
	if (pdev->frame_format == wlan_frm_fmt_native_wifi) {
		/* decap to native wifi */
		qdf_mem_copy(ether_hdr, subfrm_hdr, ETHERNET_HDR_LEN);
		qdf_nbuf_pull_head(msdu, ETHERNET_HDR_LEN);
		ol_rx_decap_to_native_wifi(vdev, msdu, info, ether_hdr);
	} else if (pdev->frame_format == wlan_frm_fmt_802_3) {
		if (pdev->sw_rx_llc_proc_enable) {
			/* remove llc snap hdr if it's necessary according to
			 * 802.11 table P-3
			 */
			qdf_mem_copy(ether_hdr, subfrm_hdr, ETHERNET_HDR_LEN);
			qdf_nbuf_pull_head(msdu, ETHERNET_HDR_LEN);
			ol_rx_decap_to_8023(vdev, msdu, info, ether_hdr);
		} else {
			/* subfrm of A-MSDU is already in 802.3 format.
			 * if target HW or FW has done LLC rmv process,
			 * we do nothing here.
			 */
		}
	} else {
		/* todo for othertype */
	}
	return A_OK;

}

static inline A_STATUS
ol_rx_decap_msdu(struct ol_txrx_vdev_t *vdev,
		 qdf_nbuf_t msdu, struct ol_rx_decap_info_t *info)
{
	struct ol_txrx_pdev_t *pdev = vdev->pdev;
	struct ieee80211_frame *wh;

	wh = (struct ieee80211_frame *)qdf_nbuf_data(msdu);

	if (pdev->frame_format == wlan_frm_fmt_native_wifi) {
		/* Decap to native wifi because according to MSFT(
		 * MSFT: http://msdn.microsoft.com/en-us/library/windows/
		 * hardware/ff552608(v=vs.85).aspx),
		 * we need to remove Qos and HTC field before indicate to OS.
		 */
		if (IEEE80211_QOS_HAS_SEQ(wh)) {
			info->hdr_len = ol_txrx_ieee80211_hdrsize(wh);
			TXRX_ASSERT2(info->hdr_len <= sizeof(info->hdr));
			qdf_mem_copy(info->hdr, /* use info->hdr as temp buf. */
				     wh, info->hdr_len);
			qdf_nbuf_pull_head(msdu, info->hdr_len);
			ol_rx_decap_to_native_wifi(vdev, msdu, info, NULL);
			/*                           802.11 hdr^  eth_hdr^ */
		}
	} else if (pdev->frame_format == wlan_frm_fmt_802_3) {
		if (pdev->sw_rx_llc_proc_enable) {
			info->hdr_len = ol_txrx_ieee80211_hdrsize(wh);
			TXRX_ASSERT2(info->hdr_len <= sizeof(info->hdr));
			qdf_mem_copy(info->hdr, /* use info->hdr as temp buf. */
				     wh, info->hdr_len);
			qdf_nbuf_pull_head(msdu, info->hdr_len);
			/* remove llc snap hdr if it's necessary according to
			 * 802.11 table P-3
			 */
			ol_rx_decap_to_8023(vdev, msdu, info,   /* 802.11 hdr */
					    NULL);      /* ethernet hdr */
		} else {
			/* Subfrm of A-MSDU is already in 802.3 format.
			 * And if target HW or FW has done LLC rmv process (
			 * sw_rx_lc_proc_enable == 0), we do nothing here.
			 */
		}
	} else {
		/* todo for othertype */
	}
	return A_OK;

}

A_STATUS
ol_rx_decap(struct ol_txrx_vdev_t *vdev,
	    struct ol_txrx_peer_t *peer,
	    qdf_nbuf_t msdu, struct ol_rx_decap_info_t *info)
{
	A_STATUS status;
	uint8_t *mpdu_hdr;

	if (!info->is_subfrm) {
		if (info->is_msdu_cmpl_mpdu && !info->is_first_subfrm) {
			/* It's normal MSDU. */
		} else {
			/*
			 * It's a first subfrm of A-MSDU and
			 * may also be the last subfrm of A-MSDU
			 */
			info->is_subfrm = 1;
			info->hdr_len = 0;
			if (vdev->pdev->sw_subfrm_hdr_recovery_enable) {
				/* we save the first subfrm mpdu hdr for
				 * subsequent subfrm 802.11 header recovery
				 * in certain chip(such as Riva).
				 */
				mpdu_hdr = qdf_nbuf_data(msdu);
				info->hdr_len =
					ol_txrx_ieee80211_hdrsize(mpdu_hdr);
				TXRX_ASSERT2(info->hdr_len <=
					     sizeof(info->hdr));
				qdf_mem_copy(info->hdr, mpdu_hdr,
					     info->hdr_len);
				qdf_nbuf_pull_head(msdu, info->hdr_len);
			}
		}
	}

	if (info->is_subfrm && vdev->pdev->sw_subfrm_hdr_recovery_enable) {
		/*
		 * This case is enabled for some HWs (such as Riva). The HW
		 * de-aggregate doesn't have capability to generate 802.11
		 * header for non-first subframe of A-MSDU. That means sw needs
		 * to cache the first subfrm mpdu header to generate the
		 * subsequent subfrm's 802.11 header.
		 */
		TXRX_ASSERT2(info->hdr_len != 0);
		status = ol_rx_decap_subfrm_amsdu(vdev, msdu, info);
	} else {
		status = ol_rx_decap_msdu(vdev, msdu, info);
	}

	if (info->is_msdu_cmpl_mpdu)
		info->is_subfrm = info->is_first_subfrm = info->hdr_len = 0;

	return status;
}
#endif