C++ skb_set_tail_pointer函数代码示例

/**
 * SIPC header_create() family functions
 *
 * Create SIPC5 header
 *
 * sipc5_hdr_create_skb()
 *	Create common SIPC5 header
 *
 * sipc5_hdr_create_legacy_rfs()
 *	Create SIPC5 header with IPC4.1 RFS header
 *	Because IMC modem used the 256KB rfs packet and RILD check the full
 *	packet with RFS header len, kernel remove the SIPC5 header and add the
 *	lagacy RFS header.
 *
 * sipc5_hdr_create_multifmt()
 *	TBD
 *
 * sipc5_hdr_create_skb_handover()
 *	Remove the ethernet frame When use `handover' with Network Bridge,
 *	user -> bridge device(rmnet0) -> real rmnet(xxxx_rmnet0) -> here.
 *	bridge device is ethernet device unlike xxxx_rmnet(net device).
 *	We remove the an ethernet header of skb before using skb->len,
 *	because bridge device added an ethernet header to skb.
 *
 * RETURN
 *	Returns the socket buffer that added SIPC5 header.
 *
 **/
static struct sk_buff *sipc5_hdr_create(struct io_device *iod,
				struct sipc_hdr *hdr, struct sk_buff *skb)
{
	struct sipc5_link_hdr *sipc5h;
	struct link_device *ld = get_current_link(iod);

	if (skb->len > 0xFFFF - SIPC5_HDR_LEN_MAX) {
		sipc5h = (struct sipc5_link_hdr *)
					skb_push(skb, SIPC5_HDR_LEN_EXT);
		sipc5h->cfg = SIPC5_HDR_CFG_START | SIPC5_HDR_EXT;
		*((u32 *)&sipc5h->len) = (u32)(skb->len);
	} else {
		sipc5h = (struct sipc5_link_hdr *)
					skb_push(skb, SIPC5_HDR_LEN);
		sipc5h->cfg = SIPC5_HDR_CFG_START;
		sipc5h->len = (u16)(skb->len);
	}
	sipc5h->ch = iod->id;

	/* Should check the alignment for dynamic switch link dev*/
	if (ld->aligned) {
		sipc5h->cfg |= SIPC5_HDR_PAD;
		skb_set_tail_pointer(skb, SIPC_ALIGN(skb->len));
		skb->len = SIPC_ALIGN(skb->len);
	}
	skbpriv(skb)->sipch = (void *)sipc5h;
	return skb;
}

static int
linux_if_rx(struct vr_interface *vif, struct vr_packet *pkt)
{
    int rc;
    struct net_device *dev = (struct net_device *)vif->vif_os;
    struct sk_buff *skb = vp_os_packet(pkt);
    struct vr_ip *ip;
    unsigned short network_off, transport_off, cksum_off = 0;

    skb->data = pkt->vp_head + pkt->vp_data;
    skb->len = pkt_len(pkt);
    skb_set_tail_pointer(skb, pkt_head_len(pkt));

    if (!dev) {
        kfree_skb(skb);
        goto exit_rx;
    }

    (void)__sync_fetch_and_add(&dev->stats.rx_bytes, skb->len);
    (void)__sync_fetch_and_add(&dev->stats.rx_packets, 1);

    /* this is only needed for mirroring */
    if ((pkt->vp_flags & VP_FLAG_FROM_DP) &&
            (pkt->vp_flags & VP_FLAG_CSUM_PARTIAL)) {
    	network_off = pkt_get_network_header_off(pkt);
    	ip = (struct vr_ip *)(pkt_data_at_offset(pkt, network_off));
    	transport_off = network_off + (ip->ip_hl * 4);

        if (ip->ip_proto == VR_IP_PROTO_TCP)
            cksum_off = offsetof(struct vr_tcp, tcp_csum);
        else if (ip->ip_proto == VR_IP_PROTO_UDP)

static struct recv_buf *sd_recv_rxfifo(struct adapter *adapter, u32 size)
{
	u32 readsize, ret;
	u8 *readbuf;
	struct recv_priv *recv_priv;
	struct recv_buf	*recvbuf;


	/*  Patch for some SDIO Host 4 bytes issue */
	/*  ex. RK3188 */
	readsize = RND4(size);

	/* 3 1. alloc recvbuf */
	recv_priv = &adapter->recvpriv;
	recvbuf = rtw_dequeue_recvbuf(&recv_priv->free_recv_buf_queue);
	if (!recvbuf) {
		DBG_871X_LEVEL(_drv_err_, "%s: alloc recvbuf FAIL!\n", __func__);
		return NULL;
	}

	/* 3 2. alloc skb */
	if (!recvbuf->pskb) {
		SIZE_PTR tmpaddr = 0;
		SIZE_PTR alignment = 0;

		recvbuf->pskb = rtw_skb_alloc(MAX_RECVBUF_SZ + RECVBUFF_ALIGN_SZ);

		if (recvbuf->pskb) {
			recvbuf->pskb->dev = adapter->pnetdev;

			tmpaddr = (SIZE_PTR)recvbuf->pskb->data;
			alignment = tmpaddr & (RECVBUFF_ALIGN_SZ-1);
			skb_reserve(recvbuf->pskb, (RECVBUFF_ALIGN_SZ - alignment));
		}

		if (!recvbuf->pskb) {
			DBG_871X("%s: alloc_skb fail! read =%d\n", __func__, readsize);
			return NULL;
		}
	}

	/* 3 3. read data from rxfifo */
	readbuf = recvbuf->pskb->data;
	ret = sdio_read_port(&adapter->iopriv.intf, WLAN_RX0FF_DEVICE_ID, readsize, readbuf);
	if (ret == _FAIL) {
		RT_TRACE(_module_hci_ops_os_c_, _drv_err_, ("%s: read port FAIL!\n", __func__));
		return NULL;
	}


	/* 3 4. init recvbuf */
	recvbuf->len = size;
	recvbuf->phead = recvbuf->pskb->head;
	recvbuf->pdata = recvbuf->pskb->data;
	skb_set_tail_pointer(recvbuf->pskb, size);
	recvbuf->ptail = skb_tail_pointer(recvbuf->pskb);
	recvbuf->pend = skb_end_pointer(recvbuf->pskb);

	return recvbuf;
}

static struct sk_buff *
net1080_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
	struct sk_buff		*skb2;
	struct nc_header	*header = NULL;
	struct nc_trailer	*trailer = NULL;
	int			padlen = sizeof (struct nc_trailer);
	int			len = skb->len;

	if (!((len + padlen + sizeof (struct nc_header)) & 0x01))
		padlen++;
	if (!skb_cloned(skb)) {
		int	headroom = skb_headroom(skb);
		int	tailroom = skb_tailroom(skb);

		if (padlen <= tailroom &&
		    sizeof(struct nc_header) <= headroom)
			/* There's enough head and tail room */
			goto encapsulate;

		if ((sizeof (struct nc_header) + padlen) <
				(headroom + tailroom)) {
			/* There's enough total room, so just readjust */
			skb->data = memmove(skb->head
						+ sizeof (struct nc_header),
					    skb->data, skb->len);
			skb_set_tail_pointer(skb, len);
			goto encapsulate;
		}
	}

	/* Create a new skb to use with the correct size */
	skb2 = skb_copy_expand(skb,
				sizeof (struct nc_header),
				padlen,
				flags);
	dev_kfree_skb_any(skb);
	if (!skb2)
		return skb2;
	skb = skb2;

encapsulate:
	/* header first */
	header = (struct nc_header *) skb_push(skb, sizeof *header);
	header->hdr_len = cpu_to_le16(sizeof (*header));
	header->packet_len = cpu_to_le16(len);
	header->packet_id = cpu_to_le16((u16)dev->xid++);

	/* maybe pad; then trailer */
	if (!((skb->len + sizeof *trailer) & 0x01))
		*skb_put(skb, 1) = PAD_BYTE;
	trailer = (struct nc_trailer *) skb_put(skb, sizeof *trailer);
	put_unaligned(header->packet_id, &trailer->packet_id);
#if 0
	netdev_dbg(dev->net, "frame >tx h %d p %d id %d\n",
		   header->hdr_len, header->packet_len,
		   header->packet_id);
#endif
	return skb;
}

void r8712_recv_indicatepkt(struct _adapter *padapter,
			    union recv_frame *precv_frame)
{
	struct recv_priv *precvpriv;
	struct  __queue	*pfree_recv_queue;
	_pkt *skb;
	struct rx_pkt_attrib *pattrib = &precv_frame->u.hdr.attrib;

	precvpriv = &(padapter->recvpriv);
	pfree_recv_queue = &(precvpriv->free_recv_queue);
	skb = precv_frame->u.hdr.pkt;
	if (skb == NULL)
		goto _recv_indicatepkt_drop;
	skb->data = precv_frame->u.hdr.rx_data;
	skb->len = precv_frame->u.hdr.len;
	skb_set_tail_pointer(skb, skb->len);
	if ((pattrib->tcpchk_valid == 1) && (pattrib->tcp_chkrpt == 1))
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	else
		skb->ip_summed = CHECKSUM_NONE;
	skb->dev = padapter->pnetdev;
	skb->protocol = eth_type_trans(skb, padapter->pnetdev);
	netif_rx(skb);
	precv_frame->u.hdr.pkt = NULL; /* pointers to NULL before
					* r8712_free_recvframe() */
	r8712_free_recvframe(precv_frame, pfree_recv_queue);
	return;
_recv_indicatepkt_drop:
	 /*enqueue back to free_recv_queue*/
	 if (precv_frame)
		r8712_free_recvframe(precv_frame, pfree_recv_queue);
	 precvpriv->rx_drop++;
}

static struct recv_buf* sd_recv_rxfifo(PADAPTER padapter, u32 size)
{
	u32 readsize, ret;
	u8 *preadbuf;
	struct recv_priv *precvpriv;
	struct recv_buf	*precvbuf;


	readsize = size;

	//3 1. alloc recvbuf
	precvpriv = &padapter->recvpriv;
	precvbuf = rtw_dequeue_recvbuf(&precvpriv->free_recv_buf_queue);
	if (precvbuf == NULL) {
		RT_TRACE(_module_hci_ops_os_c_, _drv_err_, ("%s: alloc recvbuf FAIL!\n", __FUNCTION__));
		return NULL;
	}

	//3 2. alloc skb
	if (precvbuf->pskb == NULL) {
		SIZE_PTR tmpaddr=0;
		SIZE_PTR alignment=0;

		precvbuf->pskb = rtw_skb_alloc(MAX_RECVBUF_SZ + RECVBUFF_ALIGN_SZ);

		if(precvbuf->pskb)
		{
			precvbuf->pskb->dev = padapter->pnetdev;

			tmpaddr = (SIZE_PTR)precvbuf->pskb->data;
			alignment = tmpaddr & (RECVBUFF_ALIGN_SZ-1);
			skb_reserve(precvbuf->pskb, (RECVBUFF_ALIGN_SZ - alignment));
		}

		if (precvbuf->pskb == NULL) {
			DBG_871X("%s: alloc_skb fail! read=%d\n", __FUNCTION__, readsize);
			return NULL;
		}
	}

	//3 3. read data from rxfifo
	preadbuf = precvbuf->pskb->data;
//	rtw_read_port(padapter, WLAN_RX0FF_DEVICE_ID, readsize, preadbuf);
	ret = sdio_read_port(&padapter->iopriv.intf, WLAN_RX0FF_DEVICE_ID, readsize, preadbuf);
	if (ret == _FAIL) {
		RT_TRACE(_module_hci_ops_os_c_, _drv_err_, ("%s: read port FAIL!\n", __FUNCTION__));
		return NULL;
	}


	//3 4. init recvbuf
	precvbuf->len = readsize;
	precvbuf->phead = precvbuf->pskb->head;
	precvbuf->pdata = precvbuf->pskb->data;
	skb_set_tail_pointer(precvbuf->pskb, readsize);
	precvbuf->ptail = skb_tail_pointer(precvbuf->pskb);
	precvbuf->pend = skb_end_pointer(precvbuf->pskb);

	return precvbuf;
}

int rtw_recv_indicatepkt(_adapter *padapter, union recv_frame *precv_frame)
{
	struct recv_priv *precvpriv;
	_queue	*pfree_recv_queue;
	_pkt *skb;
	struct rx_pkt_attrib *pattrib = &precv_frame->u.hdr.attrib;

	DBG_COUNTER(padapter->rx_logs.os_indicate);

	precvpriv = &(padapter->recvpriv);
	pfree_recv_queue = &(precvpriv->free_recv_queue);

	skb = precv_frame->u.hdr.pkt;
	if (skb == NULL)
	{
		RT_TRACE(_module_recv_osdep_c_, _drv_err_, ("rtw_recv_indicatepkt():skb ==NULL something wrong!!!!\n"));
		goto _recv_indicatepkt_drop;
	}

	RT_TRACE(_module_recv_osdep_c_, _drv_info_, ("rtw_recv_indicatepkt():skb != NULL !!!\n"));
	RT_TRACE(_module_recv_osdep_c_, _drv_info_, ("rtw_recv_indicatepkt():precv_frame->u.hdr.rx_head =%p  precv_frame->hdr.rx_data =%p\n", precv_frame->u.hdr.rx_head, precv_frame->u.hdr.rx_data));
	RT_TRACE(_module_recv_osdep_c_, _drv_info_, ("precv_frame->hdr.rx_tail =%p precv_frame->u.hdr.rx_end =%p precv_frame->hdr.len =%d \n", precv_frame->u.hdr.rx_tail, precv_frame->u.hdr.rx_end, precv_frame->u.hdr.len));

	skb->data = precv_frame->u.hdr.rx_data;

	skb_set_tail_pointer(skb, precv_frame->u.hdr.len);

	skb->len = precv_frame->u.hdr.len;

	RT_TRACE(_module_recv_osdep_c_, _drv_info_, ("\n skb->head =%p skb->data =%p skb->tail =%p skb->end =%p skb->len =%d\n", skb->head, skb->data, skb_tail_pointer(skb), skb_end_pointer(skb), skb->len));

#ifdef CONFIG_AUTO_AP_MODE
	if (0x8899 == pattrib->eth_type)
	{
		rtw_os_ksocket_send(padapter, precv_frame);

		/* goto _recv_indicatepkt_drop; */
	}
#endif /* CONFIG_AUTO_AP_MODE */

	rtw_os_recv_indicate_pkt(padapter, skb, pattrib);

	precv_frame->u.hdr.pkt = NULL; /*  pointers to NULL before rtw_free_recvframe() */

	rtw_free_recvframe(precv_frame, pfree_recv_queue);

	RT_TRACE(_module_recv_osdep_c_, _drv_info_, ("\n rtw_recv_indicatepkt :after rtw_os_recv_indicate_pkt!!!!\n"));

        return _SUCCESS;

_recv_indicatepkt_drop:

	 /* enqueue back to free_recv_queue */
	 if (precv_frame)
		 rtw_free_recvframe(precv_frame, pfree_recv_queue);

	 DBG_COUNTER(padapter->rx_logs.os_indicate_err);
	 return _FAIL;
}

_pkt *rtw_os_alloc_msdu_pkt(union recv_frame *prframe, u16 nSubframe_Length, u8 *pdata)
{
	u16	eth_type;
	u8	*data_ptr;
	_pkt *sub_skb;
	struct rx_pkt_attrib *pattrib;

	pattrib = &prframe->u.hdr.attrib;

#ifdef CONFIG_SKB_COPY
	sub_skb = rtw_skb_alloc(nSubframe_Length + 12);
	if(sub_skb)
	{
		skb_reserve(sub_skb, 12);
		data_ptr = (u8 *)skb_put(sub_skb, nSubframe_Length);
		_rtw_memcpy(data_ptr, (pdata + ETH_HLEN), nSubframe_Length);
	}
	else
#endif // CONFIG_SKB_COPY
	{
		sub_skb = rtw_skb_clone(prframe->u.hdr.pkt);
		if(sub_skb)
		{
			sub_skb->data = pdata + ETH_HLEN;
			sub_skb->len = nSubframe_Length;
			skb_set_tail_pointer(sub_skb, nSubframe_Length);
		}
		else
		{
			DBG_871X("%s(): rtw_skb_clone() Fail!!!\n",__FUNCTION__);
			return NULL;
		}
	}

	eth_type = RTW_GET_BE16(&sub_skb->data[6]);

	if (sub_skb->len >= 8 &&
		((_rtw_memcmp(sub_skb->data, rtw_rfc1042_header, SNAP_SIZE) &&
		  eth_type != ETH_P_AARP && eth_type != ETH_P_IPX) ||
		 _rtw_memcmp(sub_skb->data, rtw_bridge_tunnel_header, SNAP_SIZE) )) {
		/* remove RFC1042 or Bridge-Tunnel encapsulation and replace EtherType */
		skb_pull(sub_skb, SNAP_SIZE);
		_rtw_memcpy(skb_push(sub_skb, ETH_ALEN), pattrib->src, ETH_ALEN);
		_rtw_memcpy(skb_push(sub_skb, ETH_ALEN), pattrib->dst, ETH_ALEN);
	} else {
		u16 len;
		/* Leave Ethernet header part of hdr and full payload */
		len = htons(sub_skb->len);
		_rtw_memcpy(skb_push(sub_skb, 2), &len, 2);
		_rtw_memcpy(skb_push(sub_skb, ETH_ALEN), pattrib->src, ETH_ALEN);
		_rtw_memcpy(skb_push(sub_skb, ETH_ALEN), pattrib->dst, ETH_ALEN);
	}

	return sub_skb;
}

static struct sk_buff *int51x1_tx_fixup(struct usbnet *dev,
		struct sk_buff *skb, gfp_t flags)
{
	int pack_len = skb->len;
	int pack_with_header_len = pack_len + INT51X1_HEADER_SIZE;
	int headroom = skb_headroom(skb);
	int tailroom = skb_tailroom(skb);
	int need_tail = 0;
	__le16 *len;

	/*                                                              */
	if ((pack_with_header_len) < dev->maxpacket)
		need_tail = dev->maxpacket - pack_with_header_len + 1;
	/*
                                                                    
                                                                     
                                 
  */
	else if (!(pack_with_header_len % dev->maxpacket))
		need_tail = 1;

	if (!skb_cloned(skb) &&
			(headroom + tailroom >= need_tail + INT51X1_HEADER_SIZE)) {
		if (headroom < INT51X1_HEADER_SIZE || tailroom < need_tail) {
			skb->data = memmove(skb->head + INT51X1_HEADER_SIZE,
					skb->data, skb->len);
			skb_set_tail_pointer(skb, skb->len);
		}
	} else {
		struct sk_buff *skb2;

		skb2 = skb_copy_expand(skb,
				INT51X1_HEADER_SIZE,
				need_tail,
				flags);
		dev_kfree_skb_any(skb);
		if (!skb2)
			return NULL;
		skb = skb2;
	}

	pack_len += need_tail;
	pack_len &= 0x07ff;

	len = (__le16 *) __skb_push(skb, INT51X1_HEADER_SIZE);
	*len = cpu_to_le16(pack_len);

	if(need_tail)
		memset(__skb_put(skb, need_tail), 0, need_tail);

	return skb;
}

static struct sk_buff *
rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
	struct rndis_data_hdr	*hdr;
	struct sk_buff		*skb2;
	unsigned		len = skb->len;

	if (likely(!skb_cloned(skb))) {
		int	room = skb_headroom(skb);

		/* enough head room as-is? */
		if (unlikely((sizeof *hdr) <= room))
			goto fill;

		/* enough room, but needs to be readjusted? */
		room += skb_tailroom(skb);
		if (likely((sizeof *hdr) <= room)) {
			skb->data = memmove(skb->head + sizeof *hdr,
					    skb->data, len);
			skb_set_tail_pointer(skb, len);
			goto fill;
		}
	}

	/* create a new skb, with the correct size (and tailpad) */
	skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
	dev_kfree_skb_any(skb);
	if (unlikely(!skb2))
		return skb2;
	skb = skb2;

	/* fill out the RNDIS header.  we won't bother trying to batch
	 * packets; Linux minimizes wasted bandwidth through tx queues.
	 */
fill:
	hdr = (void *) __skb_push(skb, sizeof *hdr);
	memset(hdr, 0, sizeof *hdr);
	hdr->msg_type = RNDIS_MSG_PACKET;
	hdr->msg_len = cpu_to_le32(skb->len);
	hdr->data_offset = ccpu2(sizeof(*hdr) - 8);
	hdr->data_len = cpu_to_le32(len);

	/* FIXME make the last packet always be short ... */
	return skb;
}

int rtw_recv_monitor(_adapter *padapter, union recv_frame *precv_frame)
{
	int ret = _FAIL;
	struct recv_priv *precvpriv;
	_queue	*pfree_recv_queue;
	_pkt *skb;
	struct mlme_priv *pmlmepriv = &padapter->mlmepriv;
	struct rx_pkt_attrib *pattrib;

	if (NULL == precv_frame)
		goto _recv_drop;

	pattrib = &precv_frame->u.hdr.attrib;
	precvpriv = &(padapter->recvpriv);
	pfree_recv_queue = &(precvpriv->free_recv_queue);

	skb = precv_frame->u.hdr.pkt;
	if (skb == NULL) {
		DBG_871X("%s :skb==NULL something wrong!!!!\n", __func__);
		goto _recv_drop;
	}

	skb->data = precv_frame->u.hdr.rx_data;
	skb_set_tail_pointer(skb, precv_frame->u.hdr.len);
	skb->len = precv_frame->u.hdr.len;
	skb->ip_summed = CHECKSUM_NONE;
	skb->pkt_type = PACKET_OTHERHOST;
	skb->protocol = htons(0x0019); /* ETH_P_80211_RAW */

	rtw_netif_rx(padapter->pnetdev, skb);

	/* pointers to NULL before rtw_free_recvframe() */
	precv_frame->u.hdr.pkt = NULL;

	ret = _SUCCESS;

_recv_drop:

	/* enqueue back to free_recv_queue */
	if (precv_frame)
		rtw_free_recvframe(precv_frame, pfree_recv_queue);

	return ret;

}

static struct sk_buff *
genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
	int 	padlen;
	int	length = skb->len;
	int	headroom = skb_headroom(skb);
	int	tailroom = skb_tailroom(skb);
	__le32	*packet_count;
	__le32	*packet_len;

	// FIXME:  magic numbers, bleech
	padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;

	if ((!skb_cloned(skb))
			&& ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
		if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
			skb->data = memmove(skb->head + (4 + 4*1),
					     skb->data, skb->len);
			skb_set_tail_pointer(skb, skb->len);
		}
	} else {
		struct sk_buff	*skb2;
		skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
		dev_kfree_skb_any(skb);
		skb = skb2;
		if (!skb)
			return NULL;
	}

	// attach the packet count to the header
	packet_count = (__le32 *) skb_push(skb, (4 + 4*1));
	packet_len = packet_count + 1;

	*packet_count = cpu_to_le32(1);
	*packet_len = cpu_to_le32(length);

	// add padding byte
	if ((skb->len % dev->maxpacket) == 0)
		skb_put(skb, 1);

	return skb;
}

struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
			     struct cfpkt *addpkt,
			     u16 expectlen)
{
	struct sk_buff *dst = pkt_to_skb(dstpkt);
	struct sk_buff *add = pkt_to_skb(addpkt);
	u16 addlen = skb_headlen(add);
	u16 neededtailspace;
	struct sk_buff *tmp;
	u16 dstlen;
	u16 createlen;
	if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
		cfpkt_destroy(addpkt);
		return dstpkt;
	}
	if (expectlen > addlen)
		neededtailspace = expectlen;
	else
		neededtailspace = addlen;

	if (dst->tail + neededtailspace > dst->end) {
		/* Create a dumplicate of 'dst' with more tail space */
		struct cfpkt *tmppkt;
		dstlen = skb_headlen(dst);
		createlen = dstlen + neededtailspace;
		tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
		if (tmppkt == NULL)
			return NULL;
		tmp = pkt_to_skb(tmppkt);
		skb_set_tail_pointer(tmp, dstlen);
		tmp->len = dstlen;
		memcpy(tmp->data, dst->data, dstlen);
		cfpkt_destroy(dstpkt);
		dst = tmp;
	}
	memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
	cfpkt_destroy(addpkt);
	dst->tail += addlen;
	dst->len += addlen;
	return skb_to_pkt(dst);
}

static struct sk_buff *sipc5_hdr_create_ipcloopback(struct io_device *iod,
				struct sipc_hdr *hdr, struct sk_buff *skb)
{
	struct sipc5_link_hdr *sipc5h;
	struct link_device *ld = get_current_link(iod);

	sipc5h = (struct sipc5_link_hdr *)
				skb_push(skb, SIPC5_HDR_LEN);
	sipc5h->cfg = SIPC5_HDR_CFG_START;
	sipc5h->len = (u16)(skb->len);

	mif_info("send ipcloopback data: %d\n", skb->len);
	sipc5h->ch = SIPC5_CH_ID_FMT_0;

	/* Should check the alignment for dynamic switch link dev*/
	if (ld->aligned) {
		sipc5h->cfg |= SIPC5_HDR_PAD;
		skb_set_tail_pointer(skb, SIPC_ALIGN(skb->len));
		skb->len = SIPC_ALIGN(skb->len);
	}
	skbpriv(skb)->sipch = (void *)sipc5h;
	return skb;
}

struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
{
	struct sk_buff *skb2;
	struct sk_buff *skb = pkt_to_skb(pkt);
	struct cfpkt *tmppkt;
	u8 *split = skb->data + pos;
	u16 len2nd = skb_tail_pointer(skb) - split;

	if (unlikely(is_erronous(pkt)))
		return NULL;

	if (skb->data + pos > skb_tail_pointer(skb)) {
		PKT_ERROR(pkt, "trying to split beyond end of packet\n");
		return NULL;
	}

	/* Create a new packet for the second part of the data */
	tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
				  PKT_PREFIX);
	if (tmppkt == NULL)
		return NULL;
	skb2 = pkt_to_skb(tmppkt);


	if (skb2 == NULL)
		return NULL;

	/* Reduce the length of the original packet */
	skb_set_tail_pointer(skb, pos);
	skb->len = pos;

	memcpy(skb2->data, split, len2nd);
	skb2->tail += len2nd;
	skb2->len += len2nd;
	skb2->priority = skb->priority;
	return skb_to_pkt(skb2);
}