kernel-ark/net/nfc/nci/ntf.c
Christophe Ricard 9e87f9a9c4 NFC: nci: Add support for proprietary RF Protocols
In NFC Forum NCI specification, some RF Protocol values are
reserved for proprietary use (from 0x80 to 0xfe).
Some CLF vendor may need to use one value within this range
for specific technology.
Furthermore, some CLF may not becompliant with NFC Froum NCI
specification 2.0 and therefore will not support RF Protocol
value 0x06 for PROTOCOL_T5T as mention in a draft specification
and in a recent push.

Adding get_rf_protocol handle to the nci_ops structure will
help to set the correct technology to target.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-24 02:02:24 +02:00

648 lines
18 KiB
C

/*
* The NFC Controller Interface is the communication protocol between an
* NFC Controller (NFCC) and a Device Host (DH).
*
* Copyright (C) 2014 Marvell International Ltd.
* Copyright (C) 2011 Texas Instruments, Inc.
*
* Written by Ilan Elias <ilane@ti.com>
*
* Acknowledgements:
* This file is based on hci_event.c, which was written
* by Maxim Krasnyansky.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>
#include "../nfc.h"
#include <net/nfc/nci.h>
#include <net/nfc/nci_core.h>
#include <linux/nfc.h>
/* Handle NCI Notification packets */
static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev,
struct sk_buff *skb)
{
struct nci_core_conn_credit_ntf *ntf = (void *) skb->data;
int i;
pr_debug("num_entries %d\n", ntf->num_entries);
if (ntf->num_entries > NCI_MAX_NUM_CONN)
ntf->num_entries = NCI_MAX_NUM_CONN;
/* update the credits */
for (i = 0; i < ntf->num_entries; i++) {
ntf->conn_entries[i].conn_id =
nci_conn_id(&ntf->conn_entries[i].conn_id);
pr_debug("entry[%d]: conn_id %d, credits %d\n",
i, ntf->conn_entries[i].conn_id,
ntf->conn_entries[i].credits);
if (ntf->conn_entries[i].conn_id == NCI_STATIC_RF_CONN_ID) {
/* found static rf connection */
atomic_add(ntf->conn_entries[i].credits,
&ndev->credits_cnt);
}
}
/* trigger the next tx */
if (!skb_queue_empty(&ndev->tx_q))
queue_work(ndev->tx_wq, &ndev->tx_work);
}
static void nci_core_generic_error_ntf_packet(struct nci_dev *ndev,
struct sk_buff *skb)
{
__u8 status = skb->data[0];
pr_debug("status 0x%x\n", status);
if (atomic_read(&ndev->state) == NCI_W4_HOST_SELECT) {
/* Activation failed, so complete the request
(the state remains the same) */
nci_req_complete(ndev, status);
}
}
static void nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev,
struct sk_buff *skb)
{
struct nci_core_intf_error_ntf *ntf = (void *) skb->data;
ntf->conn_id = nci_conn_id(&ntf->conn_id);
pr_debug("status 0x%x, conn_id %d\n", ntf->status, ntf->conn_id);
/* complete the data exchange transaction, if exists */
if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags))
nci_data_exchange_complete(ndev, NULL, -EIO);
}
static __u8 *nci_extract_rf_params_nfca_passive_poll(struct nci_dev *ndev,
struct rf_tech_specific_params_nfca_poll *nfca_poll,
__u8 *data)
{
nfca_poll->sens_res = __le16_to_cpu(*((__u16 *)data));
data += 2;
nfca_poll->nfcid1_len = min_t(__u8, *data++, NFC_NFCID1_MAXSIZE);
pr_debug("sens_res 0x%x, nfcid1_len %d\n",
nfca_poll->sens_res, nfca_poll->nfcid1_len);
memcpy(nfca_poll->nfcid1, data, nfca_poll->nfcid1_len);
data += nfca_poll->nfcid1_len;
nfca_poll->sel_res_len = *data++;
if (nfca_poll->sel_res_len != 0)
nfca_poll->sel_res = *data++;
pr_debug("sel_res_len %d, sel_res 0x%x\n",
nfca_poll->sel_res_len,
nfca_poll->sel_res);
return data;
}
static __u8 *nci_extract_rf_params_nfcb_passive_poll(struct nci_dev *ndev,
struct rf_tech_specific_params_nfcb_poll *nfcb_poll,
__u8 *data)
{
nfcb_poll->sensb_res_len = min_t(__u8, *data++, NFC_SENSB_RES_MAXSIZE);
pr_debug("sensb_res_len %d\n", nfcb_poll->sensb_res_len);
memcpy(nfcb_poll->sensb_res, data, nfcb_poll->sensb_res_len);
data += nfcb_poll->sensb_res_len;
return data;
}
static __u8 *nci_extract_rf_params_nfcf_passive_poll(struct nci_dev *ndev,
struct rf_tech_specific_params_nfcf_poll *nfcf_poll,
__u8 *data)
{
nfcf_poll->bit_rate = *data++;
nfcf_poll->sensf_res_len = min_t(__u8, *data++, NFC_SENSF_RES_MAXSIZE);
pr_debug("bit_rate %d, sensf_res_len %d\n",
nfcf_poll->bit_rate, nfcf_poll->sensf_res_len);
memcpy(nfcf_poll->sensf_res, data, nfcf_poll->sensf_res_len);
data += nfcf_poll->sensf_res_len;
return data;
}
static __u8 *nci_extract_rf_params_nfcv_passive_poll(struct nci_dev *ndev,
struct rf_tech_specific_params_nfcv_poll *nfcv_poll,
__u8 *data)
{
++data;
nfcv_poll->dsfid = *data++;
memcpy(nfcv_poll->uid, data, NFC_ISO15693_UID_MAXSIZE);
data += NFC_ISO15693_UID_MAXSIZE;
return data;
}
__u32 nci_get_prop_rf_protocol(struct nci_dev *ndev, __u8 rf_protocol)
{
if (ndev->ops->get_rfprotocol)
return ndev->ops->get_rfprotocol(ndev, rf_protocol);
return 0;
}
static int nci_add_new_protocol(struct nci_dev *ndev,
struct nfc_target *target,
__u8 rf_protocol,
__u8 rf_tech_and_mode,
void *params)
{
struct rf_tech_specific_params_nfca_poll *nfca_poll;
struct rf_tech_specific_params_nfcb_poll *nfcb_poll;
struct rf_tech_specific_params_nfcf_poll *nfcf_poll;
struct rf_tech_specific_params_nfcv_poll *nfcv_poll;
__u32 protocol;
if (rf_protocol == NCI_RF_PROTOCOL_T1T)
protocol = NFC_PROTO_JEWEL_MASK;
else if (rf_protocol == NCI_RF_PROTOCOL_T2T)
protocol = NFC_PROTO_MIFARE_MASK;
else if (rf_protocol == NCI_RF_PROTOCOL_ISO_DEP)
if (rf_tech_and_mode == NCI_NFC_A_PASSIVE_POLL_MODE)
protocol = NFC_PROTO_ISO14443_MASK;
else
protocol = NFC_PROTO_ISO14443_B_MASK;
else if (rf_protocol == NCI_RF_PROTOCOL_T3T)
protocol = NFC_PROTO_FELICA_MASK;
else if (rf_protocol == NCI_RF_PROTOCOL_NFC_DEP)
protocol = NFC_PROTO_NFC_DEP_MASK;
else if (rf_protocol == NCI_RF_PROTOCOL_T5T)
protocol = NFC_PROTO_ISO15693_MASK;
else
protocol = nci_get_prop_rf_protocol(ndev, rf_protocol);
if (!(protocol & ndev->poll_prots)) {
pr_err("the target found does not have the desired protocol\n");
return -EPROTO;
}
if (rf_tech_and_mode == NCI_NFC_A_PASSIVE_POLL_MODE) {
nfca_poll = (struct rf_tech_specific_params_nfca_poll *)params;
target->sens_res = nfca_poll->sens_res;
target->sel_res = nfca_poll->sel_res;
target->nfcid1_len = nfca_poll->nfcid1_len;
if (target->nfcid1_len > 0) {
memcpy(target->nfcid1, nfca_poll->nfcid1,
target->nfcid1_len);
}
} else if (rf_tech_and_mode == NCI_NFC_B_PASSIVE_POLL_MODE) {
nfcb_poll = (struct rf_tech_specific_params_nfcb_poll *)params;
target->sensb_res_len = nfcb_poll->sensb_res_len;
if (target->sensb_res_len > 0) {
memcpy(target->sensb_res, nfcb_poll->sensb_res,
target->sensb_res_len);
}
} else if (rf_tech_and_mode == NCI_NFC_F_PASSIVE_POLL_MODE) {
nfcf_poll = (struct rf_tech_specific_params_nfcf_poll *)params;
target->sensf_res_len = nfcf_poll->sensf_res_len;
if (target->sensf_res_len > 0) {
memcpy(target->sensf_res, nfcf_poll->sensf_res,
target->sensf_res_len);
}
} else if (rf_tech_and_mode == NCI_NFC_V_PASSIVE_POLL_MODE) {
nfcv_poll = (struct rf_tech_specific_params_nfcv_poll *)params;
target->is_iso15693 = 1;
target->iso15693_dsfid = nfcv_poll->dsfid;
memcpy(target->iso15693_uid, nfcv_poll->uid, NFC_ISO15693_UID_MAXSIZE);
} else {
pr_err("unsupported rf_tech_and_mode 0x%x\n", rf_tech_and_mode);
return -EPROTO;
}
target->supported_protocols |= protocol;
pr_debug("protocol 0x%x\n", protocol);
return 0;
}
static void nci_add_new_target(struct nci_dev *ndev,
struct nci_rf_discover_ntf *ntf)
{
struct nfc_target *target;
int i, rc;
for (i = 0; i < ndev->n_targets; i++) {
target = &ndev->targets[i];
if (target->logical_idx == ntf->rf_discovery_id) {
/* This target already exists, add the new protocol */
nci_add_new_protocol(ndev, target, ntf->rf_protocol,
ntf->rf_tech_and_mode,
&ntf->rf_tech_specific_params);
return;
}
}
/* This is a new target, check if we've enough room */
if (ndev->n_targets == NCI_MAX_DISCOVERED_TARGETS) {
pr_debug("not enough room, ignoring new target...\n");
return;
}
target = &ndev->targets[ndev->n_targets];
rc = nci_add_new_protocol(ndev, target, ntf->rf_protocol,
ntf->rf_tech_and_mode,
&ntf->rf_tech_specific_params);
if (!rc) {
target->logical_idx = ntf->rf_discovery_id;
ndev->n_targets++;
pr_debug("logical idx %d, n_targets %d\n", target->logical_idx,
ndev->n_targets);
}
}
void nci_clear_target_list(struct nci_dev *ndev)
{
memset(ndev->targets, 0,
(sizeof(struct nfc_target)*NCI_MAX_DISCOVERED_TARGETS));
ndev->n_targets = 0;
}
static void nci_rf_discover_ntf_packet(struct nci_dev *ndev,
struct sk_buff *skb)
{
struct nci_rf_discover_ntf ntf;
__u8 *data = skb->data;
bool add_target = true;
ntf.rf_discovery_id = *data++;
ntf.rf_protocol = *data++;
ntf.rf_tech_and_mode = *data++;
ntf.rf_tech_specific_params_len = *data++;
pr_debug("rf_discovery_id %d\n", ntf.rf_discovery_id);
pr_debug("rf_protocol 0x%x\n", ntf.rf_protocol);
pr_debug("rf_tech_and_mode 0x%x\n", ntf.rf_tech_and_mode);
pr_debug("rf_tech_specific_params_len %d\n",
ntf.rf_tech_specific_params_len);
if (ntf.rf_tech_specific_params_len > 0) {
switch (ntf.rf_tech_and_mode) {
case NCI_NFC_A_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfca_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfca_poll), data);
break;
case NCI_NFC_B_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfcb_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfcb_poll), data);
break;
case NCI_NFC_F_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfcf_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfcf_poll), data);
break;
case NCI_NFC_V_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfcv_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfcv_poll), data);
break;
default:
pr_err("unsupported rf_tech_and_mode 0x%x\n",
ntf.rf_tech_and_mode);
data += ntf.rf_tech_specific_params_len;
add_target = false;
}
}
ntf.ntf_type = *data++;
pr_debug("ntf_type %d\n", ntf.ntf_type);
if (add_target == true)
nci_add_new_target(ndev, &ntf);
if (ntf.ntf_type == NCI_DISCOVER_NTF_TYPE_MORE) {
atomic_set(&ndev->state, NCI_W4_ALL_DISCOVERIES);
} else {
atomic_set(&ndev->state, NCI_W4_HOST_SELECT);
nfc_targets_found(ndev->nfc_dev, ndev->targets,
ndev->n_targets);
}
}
static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev,
struct nci_rf_intf_activated_ntf *ntf, __u8 *data)
{
struct activation_params_nfca_poll_iso_dep *nfca_poll;
struct activation_params_nfcb_poll_iso_dep *nfcb_poll;
switch (ntf->activation_rf_tech_and_mode) {
case NCI_NFC_A_PASSIVE_POLL_MODE:
nfca_poll = &ntf->activation_params.nfca_poll_iso_dep;
nfca_poll->rats_res_len = min_t(__u8, *data++, 20);
pr_debug("rats_res_len %d\n", nfca_poll->rats_res_len);
if (nfca_poll->rats_res_len > 0) {
memcpy(nfca_poll->rats_res,
data, nfca_poll->rats_res_len);
}
break;
case NCI_NFC_B_PASSIVE_POLL_MODE:
nfcb_poll = &ntf->activation_params.nfcb_poll_iso_dep;
nfcb_poll->attrib_res_len = min_t(__u8, *data++, 50);
pr_debug("attrib_res_len %d\n", nfcb_poll->attrib_res_len);
if (nfcb_poll->attrib_res_len > 0) {
memcpy(nfcb_poll->attrib_res,
data, nfcb_poll->attrib_res_len);
}
break;
default:
pr_err("unsupported activation_rf_tech_and_mode 0x%x\n",
ntf->activation_rf_tech_and_mode);
return NCI_STATUS_RF_PROTOCOL_ERROR;
}
return NCI_STATUS_OK;
}
static int nci_extract_activation_params_nfc_dep(struct nci_dev *ndev,
struct nci_rf_intf_activated_ntf *ntf, __u8 *data)
{
struct activation_params_poll_nfc_dep *poll;
switch (ntf->activation_rf_tech_and_mode) {
case NCI_NFC_A_PASSIVE_POLL_MODE:
case NCI_NFC_F_PASSIVE_POLL_MODE:
poll = &ntf->activation_params.poll_nfc_dep;
poll->atr_res_len = min_t(__u8, *data++, 63);
pr_debug("atr_res_len %d\n", poll->atr_res_len);
if (poll->atr_res_len > 0)
memcpy(poll->atr_res, data, poll->atr_res_len);
break;
default:
pr_err("unsupported activation_rf_tech_and_mode 0x%x\n",
ntf->activation_rf_tech_and_mode);
return NCI_STATUS_RF_PROTOCOL_ERROR;
}
return NCI_STATUS_OK;
}
static void nci_target_auto_activated(struct nci_dev *ndev,
struct nci_rf_intf_activated_ntf *ntf)
{
struct nfc_target *target;
int rc;
target = &ndev->targets[ndev->n_targets];
rc = nci_add_new_protocol(ndev, target, ntf->rf_protocol,
ntf->activation_rf_tech_and_mode,
&ntf->rf_tech_specific_params);
if (rc)
return;
target->logical_idx = ntf->rf_discovery_id;
ndev->n_targets++;
pr_debug("logical idx %d, n_targets %d\n",
target->logical_idx, ndev->n_targets);
nfc_targets_found(ndev->nfc_dev, ndev->targets, ndev->n_targets);
}
static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev,
struct sk_buff *skb)
{
struct nci_rf_intf_activated_ntf ntf;
__u8 *data = skb->data;
int err = NCI_STATUS_OK;
ntf.rf_discovery_id = *data++;
ntf.rf_interface = *data++;
ntf.rf_protocol = *data++;
ntf.activation_rf_tech_and_mode = *data++;
ntf.max_data_pkt_payload_size = *data++;
ntf.initial_num_credits = *data++;
ntf.rf_tech_specific_params_len = *data++;
pr_debug("rf_discovery_id %d\n", ntf.rf_discovery_id);
pr_debug("rf_interface 0x%x\n", ntf.rf_interface);
pr_debug("rf_protocol 0x%x\n", ntf.rf_protocol);
pr_debug("activation_rf_tech_and_mode 0x%x\n",
ntf.activation_rf_tech_and_mode);
pr_debug("max_data_pkt_payload_size 0x%x\n",
ntf.max_data_pkt_payload_size);
pr_debug("initial_num_credits 0x%x\n",
ntf.initial_num_credits);
pr_debug("rf_tech_specific_params_len %d\n",
ntf.rf_tech_specific_params_len);
if (ntf.rf_tech_specific_params_len > 0) {
switch (ntf.activation_rf_tech_and_mode) {
case NCI_NFC_A_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfca_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfca_poll), data);
break;
case NCI_NFC_B_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfcb_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfcb_poll), data);
break;
case NCI_NFC_F_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfcf_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfcf_poll), data);
break;
case NCI_NFC_V_PASSIVE_POLL_MODE:
data = nci_extract_rf_params_nfcv_passive_poll(ndev,
&(ntf.rf_tech_specific_params.nfcv_poll), data);
break;
default:
pr_err("unsupported activation_rf_tech_and_mode 0x%x\n",
ntf.activation_rf_tech_and_mode);
err = NCI_STATUS_RF_PROTOCOL_ERROR;
goto exit;
}
}
ntf.data_exch_rf_tech_and_mode = *data++;
ntf.data_exch_tx_bit_rate = *data++;
ntf.data_exch_rx_bit_rate = *data++;
ntf.activation_params_len = *data++;
pr_debug("data_exch_rf_tech_and_mode 0x%x\n",
ntf.data_exch_rf_tech_and_mode);
pr_debug("data_exch_tx_bit_rate 0x%x\n", ntf.data_exch_tx_bit_rate);
pr_debug("data_exch_rx_bit_rate 0x%x\n", ntf.data_exch_rx_bit_rate);
pr_debug("activation_params_len %d\n", ntf.activation_params_len);
if (ntf.activation_params_len > 0) {
switch (ntf.rf_interface) {
case NCI_RF_INTERFACE_ISO_DEP:
err = nci_extract_activation_params_iso_dep(ndev,
&ntf, data);
break;
case NCI_RF_INTERFACE_NFC_DEP:
err = nci_extract_activation_params_nfc_dep(ndev,
&ntf, data);
break;
case NCI_RF_INTERFACE_FRAME:
/* no activation params */
break;
default:
pr_err("unsupported rf_interface 0x%x\n",
ntf.rf_interface);
err = NCI_STATUS_RF_PROTOCOL_ERROR;
break;
}
}
exit:
if (err == NCI_STATUS_OK) {
ndev->max_data_pkt_payload_size = ntf.max_data_pkt_payload_size;
ndev->initial_num_credits = ntf.initial_num_credits;
/* set the available credits to initial value */
atomic_set(&ndev->credits_cnt, ndev->initial_num_credits);
/* store general bytes to be reported later in dep_link_up */
if (ntf.rf_interface == NCI_RF_INTERFACE_NFC_DEP) {
ndev->remote_gb_len = 0;
if (ntf.activation_params_len > 0) {
/* ATR_RES general bytes at offset 15 */
ndev->remote_gb_len = min_t(__u8,
(ntf.activation_params
.poll_nfc_dep.atr_res_len
- NFC_ATR_RES_GT_OFFSET),
NFC_MAX_GT_LEN);
memcpy(ndev->remote_gb,
(ntf.activation_params.poll_nfc_dep
.atr_res + NFC_ATR_RES_GT_OFFSET),
ndev->remote_gb_len);
}
}
}
if (atomic_read(&ndev->state) == NCI_DISCOVERY) {
/* A single target was found and activated automatically */
atomic_set(&ndev->state, NCI_POLL_ACTIVE);
if (err == NCI_STATUS_OK)
nci_target_auto_activated(ndev, &ntf);
} else { /* ndev->state == NCI_W4_HOST_SELECT */
/* A selected target was activated, so complete the request */
atomic_set(&ndev->state, NCI_POLL_ACTIVE);
nci_req_complete(ndev, err);
}
}
static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev,
struct sk_buff *skb)
{
struct nci_rf_deactivate_ntf *ntf = (void *) skb->data;
pr_debug("entry, type 0x%x, reason 0x%x\n", ntf->type, ntf->reason);
/* drop tx data queue */
skb_queue_purge(&ndev->tx_q);
/* drop partial rx data packet */
if (ndev->rx_data_reassembly) {
kfree_skb(ndev->rx_data_reassembly);
ndev->rx_data_reassembly = NULL;
}
/* complete the data exchange transaction, if exists */
if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags))
nci_data_exchange_complete(ndev, NULL, -EIO);
nci_clear_target_list(ndev);
atomic_set(&ndev->state, NCI_IDLE);
nci_req_complete(ndev, NCI_STATUS_OK);
}
void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb)
{
__u16 ntf_opcode = nci_opcode(skb->data);
pr_debug("NCI RX: MT=ntf, PBF=%d, GID=0x%x, OID=0x%x, plen=%d\n",
nci_pbf(skb->data),
nci_opcode_gid(ntf_opcode),
nci_opcode_oid(ntf_opcode),
nci_plen(skb->data));
/* strip the nci control header */
skb_pull(skb, NCI_CTRL_HDR_SIZE);
switch (ntf_opcode) {
case NCI_OP_CORE_CONN_CREDITS_NTF:
nci_core_conn_credits_ntf_packet(ndev, skb);
break;
case NCI_OP_CORE_GENERIC_ERROR_NTF:
nci_core_generic_error_ntf_packet(ndev, skb);
break;
case NCI_OP_CORE_INTF_ERROR_NTF:
nci_core_conn_intf_error_ntf_packet(ndev, skb);
break;
case NCI_OP_RF_DISCOVER_NTF:
nci_rf_discover_ntf_packet(ndev, skb);
break;
case NCI_OP_RF_INTF_ACTIVATED_NTF:
nci_rf_intf_activated_ntf_packet(ndev, skb);
break;
case NCI_OP_RF_DEACTIVATE_NTF:
nci_rf_deactivate_ntf_packet(ndev, skb);
break;
default:
pr_err("unknown ntf opcode 0x%x\n", ntf_opcode);
break;
}
kfree_skb(skb);
}