Quelle  scan.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * IEEE 802.15.4 scanning management
 *
 * Copyright (C) 2021 Qorvo US, Inc
 * Authors:
 *   - David Girault <david.girault@qorvo.com>
 *   - Miquel Raynal <miquel.raynal@bootlin.com>
 */

#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <net/mac802154.h>

#include "ieee802154_i.h"
#include "driver-ops.h"
#include "../ieee802154/nl802154.h"

#define IEEE802154_BEACON_MHR_SZ 13
#define IEEE802154_BEACON_PL_SZ 4
#define IEEE802154_MAC_CMD_MHR_SZ 23
#define IEEE802154_MAC_CMD_PL_SZ 1
#define IEEE802154_BEACON_SKB_SZ (IEEE802154_BEACON_MHR_SZ + \
      IEEE802154_BEACON_PL_SZ)
#define IEEE802154_MAC_CMD_SKB_SZ (IEEE802154_MAC_CMD_MHR_SZ + \
       IEEE802154_MAC_CMD_PL_SZ)

/* mac802154_scan_cleanup_locked() must be called upon scan completion or abort.
 * - Completions are asynchronous, not locked by the rtnl and decided by the
 *   scan worker.
 * - Aborts are decided by userspace, and locked by the rtnl.
 *
 * Concurrent modifications to the PHY, the interfaces or the hardware is in
 * general prevented by the rtnl. So in most cases we don't need additional
 * protection.
 *
 * However, the scan worker get's triggered without anybody noticing and thus we
 * must ensure the presence of the devices as well as data consistency:
 * - The sub-interface and device driver module get both their reference
 *   counters incremented whenever we start a scan, so they cannot disappear
 *   during operation.
 * - Data consistency is achieved by the use of rcu protected pointers.
 */
static int mac802154_scan_cleanup_locked(struct ieee802154_local *local,
      struct ieee802154_sub_if_data *sdata,
      bool aborted)
{
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct wpan_phy *wpan_phy = local->phy;
 struct cfg802154_scan_request *request;
 u8 arg;

 /* Prevent any further use of the scan request */
 clear_bit(IEEE802154_IS_SCANNING, &local->ongoing);
 cancel_delayed_work(&local->scan_work);
 request = rcu_replace_pointer(local->scan_req, NULL, 1);
 if (!request)
  return 0;
 kvfree_rcu_mightsleep(request);

 /* Advertize first, while we know the devices cannot be removed */
 if (aborted)
  arg = NL802154_SCAN_DONE_REASON_ABORTED;
 else
  arg = NL802154_SCAN_DONE_REASON_FINISHED;
 nl802154_scan_done(wpan_phy, wpan_dev, arg);

 /* Cleanup software stack */
 ieee802154_mlme_op_post(local);

 /* Set the hardware back in its original state */
 drv_set_channel(local, wpan_phy->current_page,
   wpan_phy->current_channel);
 ieee802154_configure_durations(wpan_phy, wpan_phy->current_page,
           wpan_phy->current_channel);
 drv_stop(local);
 synchronize_net();
 sdata->required_filtering = sdata->iface_default_filtering;
 drv_start(local, sdata->required_filtering, &local->addr_filt);

 return 0;
}

int mac802154_abort_scan_locked(struct ieee802154_local *local,
    struct ieee802154_sub_if_data *sdata)
{
 ASSERT_RTNL();

 if (!mac802154_is_scanning(local))
  return -ESRCH;

 return mac802154_scan_cleanup_locked(local, sdata, true);
}

static unsigned int mac802154_scan_get_channel_time(u8 duration_order,
          u8 symbol_duration)
{
 u64 base_super_frame_duration = (u64)symbol_duration *
  IEEE802154_SUPERFRAME_PERIOD * IEEE802154_SLOT_PERIOD;

 return usecs_to_jiffies(base_super_frame_duration *
    (BIT(duration_order) + 1));
}

static void mac802154_flush_queued_beacons(struct ieee802154_local *local)
{
 struct cfg802154_mac_pkt *mac_pkt, *tmp;

 list_for_each_entry_safe(mac_pkt, tmp, &local->rx_beacon_list, node) {
  list_del(&mac_pkt->node);
  kfree_skb(mac_pkt->skb);
  kfree(mac_pkt);
 }
}

static void
mac802154_scan_get_next_channel(struct ieee802154_local *local,
    struct cfg802154_scan_request *scan_req,
    u8 *channel)
{
 (*channel)++;
 *channel = find_next_bit((const unsigned long *)&scan_req->channels,
     IEEE802154_MAX_CHANNEL + 1,
     *channel);
}

static int mac802154_scan_find_next_chan(struct ieee802154_local *local,
      struct cfg802154_scan_request *scan_req,
      u8 page, u8 *channel)
{
 mac802154_scan_get_next_channel(local, scan_req, channel);
 if (*channel > IEEE802154_MAX_CHANNEL)
  return -EINVAL;

 return 0;
}

static int mac802154_scan_prepare_beacon_req(struct ieee802154_local *local)
{
 memset(&local->scan_beacon_req, 0, sizeof(local->scan_beacon_req));
 local->scan_beacon_req.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
 local->scan_beacon_req.mhr.fc.dest_addr_mode = IEEE802154_SHORT_ADDRESSING;
 local->scan_beacon_req.mhr.fc.version = IEEE802154_2003_STD;
 local->scan_beacon_req.mhr.fc.source_addr_mode = IEEE802154_NO_ADDRESSING;
 local->scan_beacon_req.mhr.dest.mode = IEEE802154_ADDR_SHORT;
 local->scan_beacon_req.mhr.dest.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
 local->scan_beacon_req.mhr.dest.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
 local->scan_beacon_req.mac_pl.cmd_id = IEEE802154_CMD_BEACON_REQ;

 return 0;
}

static int mac802154_transmit_beacon_req(struct ieee802154_local *local,
      struct ieee802154_sub_if_data *sdata)
{
 struct sk_buff *skb;
 int ret;

 skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ, GFP_KERNEL);
 if (!skb)
  return -ENOBUFS;

 skb->dev = sdata->dev;

 ret = ieee802154_mac_cmd_push(skb, &local->scan_beacon_req, NULL, 0);
 if (ret) {
  kfree_skb(skb);
  return ret;
 }

 return ieee802154_mlme_tx(local, sdata, skb);
}

void mac802154_scan_worker(struct work_struct *work)
{
 struct ieee802154_local *local =
  container_of(work, struct ieee802154_local, scan_work.work);
 struct cfg802154_scan_request *scan_req;
 enum nl802154_scan_types scan_req_type;
 struct ieee802154_sub_if_data *sdata;
 unsigned int scan_duration = 0;
 struct wpan_phy *wpan_phy;
 u8 scan_req_duration;
 u8 page, channel;
 int ret;

 /* Ensure the device receiver is turned off when changing channels
 * because there is no atomic way to change the channel and know on
 * which one a beacon might have been received.
 */
 drv_stop(local);
 synchronize_net();
 mac802154_flush_queued_beacons(local);

 rcu_read_lock();
 scan_req = rcu_dereference(local->scan_req);
 if (unlikely(!scan_req)) {
  rcu_read_unlock();
  return;
 }

 sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(scan_req->wpan_dev);

 /* Wait an arbitrary amount of time in case we cannot use the device */
 if (local->suspended || !ieee802154_sdata_running(sdata)) {
  rcu_read_unlock();
  queue_delayed_work(local->mac_wq, &local->scan_work,
       msecs_to_jiffies(1000));
  return;
 }

 wpan_phy = scan_req->wpan_phy;
 scan_req_type = scan_req->type;
 scan_req_duration = scan_req->duration;

 /* Look for the next valid chan */
 page = local->scan_page;
 channel = local->scan_channel;
 do {
  ret = mac802154_scan_find_next_chan(local, scan_req, page, &channel);
  if (ret) {
   rcu_read_unlock();
   goto end_scan;
  }
 } while (!ieee802154_chan_is_valid(scan_req->wpan_phy, page, channel));

 rcu_read_unlock();

 /* Bypass the stack on purpose when changing the channel */
 rtnl_lock();
 ret = drv_set_channel(local, page, channel);
 rtnl_unlock();
 if (ret) {
  dev_err(&sdata->dev->dev,
   "Channel change failure during scan, aborting (%d)\n", ret);
  goto end_scan;
 }

 local->scan_page = page;
 local->scan_channel = channel;

 rtnl_lock();
 ret = drv_start(local, IEEE802154_FILTERING_3_SCAN, &local->addr_filt);
 rtnl_unlock();
 if (ret) {
  dev_err(&sdata->dev->dev,
   "Restarting failure after channel change, aborting (%d)\n", ret);
  goto end_scan;
 }

 if (scan_req_type == NL802154_SCAN_ACTIVE) {
  ret = mac802154_transmit_beacon_req(local, sdata);
  if (ret)
   dev_err(&sdata->dev->dev,
    "Error when transmitting beacon request (%d)\n", ret);
 }

 ieee802154_configure_durations(wpan_phy, page, channel);
 scan_duration = mac802154_scan_get_channel_time(scan_req_duration,
       wpan_phy->symbol_duration);
 dev_dbg(&sdata->dev->dev,
  "Scan page %u channel %u for %ums\n",
  page, channel, jiffies_to_msecs(scan_duration));
 queue_delayed_work(local->mac_wq, &local->scan_work, scan_duration);
 return;

end_scan:
 rtnl_lock();
 mac802154_scan_cleanup_locked(local, sdata, false);
 rtnl_unlock();
}

int mac802154_trigger_scan_locked(struct ieee802154_sub_if_data *sdata,
      struct cfg802154_scan_request *request)
{
 struct ieee802154_local *local = sdata->local;

 ASSERT_RTNL();

 if (mac802154_is_scanning(local))
  return -EBUSY;

 if (request->type != NL802154_SCAN_PASSIVE &&
     request->type != NL802154_SCAN_ACTIVE)
  return -EOPNOTSUPP;

 /* Store scanning parameters */
 rcu_assign_pointer(local->scan_req, request);

 /* Software scanning requires to set promiscuous mode, so we need to
 * pause the Tx queue during the entire operation.
 */
 ieee802154_mlme_op_pre(local);

 sdata->required_filtering = IEEE802154_FILTERING_3_SCAN;
 local->scan_page = request->page;
 local->scan_channel = -1;
 set_bit(IEEE802154_IS_SCANNING, &local->ongoing);
 if (request->type == NL802154_SCAN_ACTIVE)
  mac802154_scan_prepare_beacon_req(local);

 nl802154_scan_started(request->wpan_phy, request->wpan_dev);

 queue_delayed_work(local->mac_wq, &local->scan_work, 0);

 return 0;
}

int mac802154_process_beacon(struct ieee802154_local *local,
        struct sk_buff *skb,
        u8 page, u8 channel)
{
 struct ieee802154_beacon_hdr *bh = (void *)skb->data;
 struct ieee802154_addr *src = &mac_cb(skb)->source;
 struct cfg802154_scan_request *scan_req;
 struct ieee802154_coord_desc desc;

 if (skb->len != sizeof(*bh))
  return -EINVAL;

 if (unlikely(src->mode == IEEE802154_ADDR_NONE))
  return -EINVAL;

 dev_dbg(&skb->dev->dev,
  "BEACON received on page %u channel %u\n",
  page, channel);

 memcpy(&desc.addr, src, sizeof(desc.addr));
 desc.page = page;
 desc.channel = channel;
 desc.link_quality = mac_cb(skb)->lqi;
 desc.superframe_spec = get_unaligned_le16(skb->data);
 desc.gts_permit = bh->gts_permit;

 trace_802154_scan_event(&desc);

 rcu_read_lock();
 scan_req = rcu_dereference(local->scan_req);
 if (likely(scan_req))
  nl802154_scan_event(scan_req->wpan_phy, scan_req->wpan_dev, &desc);
 rcu_read_unlock();

 return 0;
}

static int mac802154_transmit_beacon(struct ieee802154_local *local,
         struct wpan_dev *wpan_dev)
{
 struct cfg802154_beacon_request *beacon_req;
 struct ieee802154_sub_if_data *sdata;
 struct sk_buff *skb;
 int ret;

 /* Update the sequence number */
 local->beacon.mhr.seq = atomic_inc_return(&wpan_dev->bsn) & 0xFF;

 skb = alloc_skb(IEEE802154_BEACON_SKB_SZ, GFP_KERNEL);
 if (!skb)
  return -ENOBUFS;

 rcu_read_lock();
 beacon_req = rcu_dereference(local->beacon_req);
 if (unlikely(!beacon_req)) {
  rcu_read_unlock();
  kfree_skb(skb);
  return -EINVAL;
 }

 sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(beacon_req->wpan_dev);
 skb->dev = sdata->dev;

 rcu_read_unlock();

 ret = ieee802154_beacon_push(skb, &local->beacon);
 if (ret) {
  kfree_skb(skb);
  return ret;
 }

 /* Using the MLME transmission helper for sending beacons is a bit
 * overkill because we do not really care about the final outcome.
 *
 * Even though, going through the whole net stack with a regular
 * dev_queue_xmit() is not relevant either because we want beacons to be
 * sent "now" rather than go through the whole net stack scheduling
 * (qdisc & co).
 *
 * Finally, using ieee802154_subif_start_xmit() would only be an option
 * if we had a generic transmit helper which would acquire the
 * HARD_TX_LOCK() to prevent buffer handling conflicts with regular
 * packets.
 *
 * So for now we keep it simple and send beacons with our MLME helper,
 * even if it stops the ieee802154 queue entirely during these
 * transmissions, wich anyway does not have a huge impact on the
 * performances given the current design of the stack.
 */
 return ieee802154_mlme_tx(local, sdata, skb);
}

void mac802154_beacon_worker(struct work_struct *work)
{
 struct ieee802154_local *local =
  container_of(work, struct ieee802154_local, beacon_work.work);
 struct cfg802154_beacon_request *beacon_req;
 struct ieee802154_sub_if_data *sdata;
 struct wpan_dev *wpan_dev;
 u8 interval;
 int ret;

 rcu_read_lock();
 beacon_req = rcu_dereference(local->beacon_req);
 if (unlikely(!beacon_req)) {
  rcu_read_unlock();
  return;
 }

 sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(beacon_req->wpan_dev);

 /* Wait an arbitrary amount of time in case we cannot use the device */
 if (local->suspended || !ieee802154_sdata_running(sdata)) {
  rcu_read_unlock();
  queue_delayed_work(local->mac_wq, &local->beacon_work,
       msecs_to_jiffies(1000));
  return;
 }

 wpan_dev = beacon_req->wpan_dev;
 interval = beacon_req->interval;

 rcu_read_unlock();

 dev_dbg(&sdata->dev->dev, "Sending beacon\n");
 ret = mac802154_transmit_beacon(local, wpan_dev);
 if (ret)
  dev_err(&sdata->dev->dev,
   "Beacon could not be transmitted (%d)\n", ret);

 if (interval < IEEE802154_ACTIVE_SCAN_DURATION)
  queue_delayed_work(local->mac_wq, &local->beacon_work,
       local->beacon_interval);
}

int mac802154_stop_beacons_locked(struct ieee802154_local *local,
      struct ieee802154_sub_if_data *sdata)
{
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct cfg802154_beacon_request *request;

 ASSERT_RTNL();

 if (!mac802154_is_beaconing(local))
  return -ESRCH;

 clear_bit(IEEE802154_IS_BEACONING, &local->ongoing);
 cancel_delayed_work(&local->beacon_work);
 request = rcu_replace_pointer(local->beacon_req, NULL, 1);
 if (!request)
  return 0;
 kvfree_rcu_mightsleep(request);

 nl802154_beaconing_done(wpan_dev);

 return 0;
}

int mac802154_send_beacons_locked(struct ieee802154_sub_if_data *sdata,
      struct cfg802154_beacon_request *request)
{
 struct ieee802154_local *local = sdata->local;
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;

 ASSERT_RTNL();

 if (mac802154_is_beaconing(local))
  mac802154_stop_beacons_locked(local, sdata);

 /* Store beaconing parameters */
 rcu_assign_pointer(local->beacon_req, request);

 set_bit(IEEE802154_IS_BEACONING, &local->ongoing);

 memset(&local->beacon, 0, sizeof(local->beacon));
 local->beacon.mhr.fc.type = IEEE802154_FC_TYPE_BEACON;
 local->beacon.mhr.fc.security_enabled = 0;
 local->beacon.mhr.fc.frame_pending = 0;
 local->beacon.mhr.fc.ack_request = 0;
 local->beacon.mhr.fc.intra_pan = 0;
 local->beacon.mhr.fc.dest_addr_mode = IEEE802154_NO_ADDRESSING;
 local->beacon.mhr.fc.version = IEEE802154_2003_STD;
 local->beacon.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
 atomic_set(&request->wpan_dev->bsn, -1);
 local->beacon.mhr.source.mode = IEEE802154_ADDR_LONG;
 local->beacon.mhr.source.pan_id = request->wpan_dev->pan_id;
 local->beacon.mhr.source.extended_addr = request->wpan_dev->extended_addr;
 local->beacon.mac_pl.beacon_order = request->interval;
 if (request->interval <= IEEE802154_MAX_SCAN_DURATION)
  local->beacon.mac_pl.superframe_order = request->interval;
 local->beacon.mac_pl.final_cap_slot = 0xf;
 local->beacon.mac_pl.battery_life_ext = 0;
 local->beacon.mac_pl.pan_coordinator = !wpan_dev->parent;
 local->beacon.mac_pl.assoc_permit = 1;

 if (request->interval == IEEE802154_ACTIVE_SCAN_DURATION)
  return 0;

 /* Start the beacon work */
 local->beacon_interval =
  mac802154_scan_get_channel_time(request->interval,
      request->wpan_phy->symbol_duration);
 queue_delayed_work(local->mac_wq, &local->beacon_work, 0);

 return 0;
}

int mac802154_perform_association(struct ieee802154_sub_if_data *sdata,
      struct ieee802154_pan_device *coord,
      __le16 *short_addr)
{
 u64 ceaddr = swab64((__force u64)coord->extended_addr);
 struct ieee802154_association_req_frame frame = {};
 struct ieee802154_local *local = sdata->local;
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct sk_buff *skb;
 int ret;

 frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
 frame.mhr.fc.security_enabled = 0;
 frame.mhr.fc.frame_pending = 0;
 frame.mhr.fc.ack_request = 1; /* We always expect an ack here */
 frame.mhr.fc.intra_pan = 0;
 frame.mhr.fc.dest_addr_mode = (coord->mode == IEEE802154_ADDR_LONG) ?
  IEEE802154_EXTENDED_ADDRESSING : IEEE802154_SHORT_ADDRESSING;
 frame.mhr.fc.version = IEEE802154_2003_STD;
 frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
 frame.mhr.source.mode = IEEE802154_ADDR_LONG;
 frame.mhr.source.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
 frame.mhr.source.extended_addr = wpan_dev->extended_addr;
 frame.mhr.dest.mode = coord->mode;
 frame.mhr.dest.pan_id = coord->pan_id;
 if (coord->mode == IEEE802154_ADDR_LONG)
  frame.mhr.dest.extended_addr = coord->extended_addr;
 else
  frame.mhr.dest.short_addr = coord->short_addr;
 frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
 frame.mac_pl.cmd_id = IEEE802154_CMD_ASSOCIATION_REQ;
 frame.assoc_req_pl.device_type = 1;
 frame.assoc_req_pl.power_source = 1;
 frame.assoc_req_pl.rx_on_when_idle = 1;
 frame.assoc_req_pl.alloc_addr = 1;

 skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(frame.assoc_req_pl),
   GFP_KERNEL);
 if (!skb)
  return -ENOBUFS;

 skb->dev = sdata->dev;

 ret = ieee802154_mac_cmd_push(skb, &frame, &frame.assoc_req_pl,
          sizeof(frame.assoc_req_pl));
 if (ret) {
  kfree_skb(skb);
  return ret;
 }

 local->assoc_dev = coord;
 reinit_completion(&local->assoc_done);
 set_bit(IEEE802154_IS_ASSOCIATING, &local->ongoing);

 ret = ieee802154_mlme_tx_one_locked(local, sdata, skb);
 if (ret) {
  if (ret > 0)
   ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
  dev_warn(&sdata->dev->dev,
    "No ASSOC REQ ACK received from %8phC\n", &ceaddr);
  goto clear_assoc;
 }

 ret = wait_for_completion_killable_timeout(&local->assoc_done, 10 * HZ);
 if (ret <= 0) {
  dev_warn(&sdata->dev->dev,
    "No ASSOC RESP received from %8phC\n", &ceaddr);
  ret = -ETIMEDOUT;
  goto clear_assoc;
 }

 if (local->assoc_status != IEEE802154_ASSOCIATION_SUCCESSFUL) {
  if (local->assoc_status == IEEE802154_PAN_AT_CAPACITY)
   ret = -ERANGE;
  else
   ret = -EPERM;

  dev_warn(&sdata->dev->dev,
    "Negative ASSOC RESP received from %8phC: %s\n", &ceaddr,
    local->assoc_status == IEEE802154_PAN_AT_CAPACITY ?
    "PAN at capacity" : "access denied");
 }

 ret = 0;
 *short_addr = local->assoc_addr;

clear_assoc:
 clear_bit(IEEE802154_IS_ASSOCIATING, &local->ongoing);
 local->assoc_dev = NULL;

 return ret;
}

int mac802154_process_association_resp(struct ieee802154_sub_if_data *sdata,
           struct sk_buff *skb)
{
 struct ieee802154_addr *src = &mac_cb(skb)->source;
 struct ieee802154_addr *dest = &mac_cb(skb)->dest;
 u64 deaddr = swab64((__force u64)dest->extended_addr);
 struct ieee802154_local *local = sdata->local;
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct ieee802154_assoc_resp_pl resp_pl = {};

 if (skb->len != sizeof(resp_pl))
  return -EINVAL;

 if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING ||
       dest->mode != IEEE802154_EXTENDED_ADDRESSING))
  return -EINVAL;

 if (unlikely(dest->extended_addr != wpan_dev->extended_addr ||
       src->extended_addr != local->assoc_dev->extended_addr))
  return -ENODEV;

 memcpy(&resp_pl, skb->data, sizeof(resp_pl));
 local->assoc_addr = resp_pl.short_addr;
 local->assoc_status = resp_pl.status;

 dev_dbg(&skb->dev->dev,
  "ASSOC RESP 0x%x received from %8phC, getting short address %04x\n",
  local->assoc_status, &deaddr, local->assoc_addr);

 complete(&local->assoc_done);

 return 0;
}

int mac802154_send_disassociation_notif(struct ieee802154_sub_if_data *sdata,
     struct ieee802154_pan_device *target,
     u8 reason)
{
 struct ieee802154_disassociation_notif_frame frame = {};
 u64 teaddr = swab64((__force u64)target->extended_addr);
 struct ieee802154_local *local = sdata->local;
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct sk_buff *skb;
 int ret;

 frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
 frame.mhr.fc.security_enabled = 0;
 frame.mhr.fc.frame_pending = 0;
 frame.mhr.fc.ack_request = 1;
 frame.mhr.fc.intra_pan = 1;
 frame.mhr.fc.dest_addr_mode = (target->mode == IEEE802154_ADDR_LONG) ?
  IEEE802154_EXTENDED_ADDRESSING : IEEE802154_SHORT_ADDRESSING;
 frame.mhr.fc.version = IEEE802154_2003_STD;
 frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
 frame.mhr.source.mode = IEEE802154_ADDR_LONG;
 frame.mhr.source.pan_id = wpan_dev->pan_id;
 frame.mhr.source.extended_addr = wpan_dev->extended_addr;
 frame.mhr.dest.mode = target->mode;
 frame.mhr.dest.pan_id = wpan_dev->pan_id;
 if (target->mode == IEEE802154_ADDR_LONG)
  frame.mhr.dest.extended_addr = target->extended_addr;
 else
  frame.mhr.dest.short_addr = target->short_addr;
 frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
 frame.mac_pl.cmd_id = IEEE802154_CMD_DISASSOCIATION_NOTIFY;
 frame.disassoc_pl = reason;

 skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(frame.disassoc_pl),
   GFP_KERNEL);
 if (!skb)
  return -ENOBUFS;

 skb->dev = sdata->dev;

 ret = ieee802154_mac_cmd_push(skb, &frame, &frame.disassoc_pl,
          sizeof(frame.disassoc_pl));
 if (ret) {
  kfree_skb(skb);
  return ret;
 }

 ret = ieee802154_mlme_tx_one_locked(local, sdata, skb);
 if (ret) {
  dev_warn(&sdata->dev->dev,
    "No DISASSOC ACK received from %8phC\n", &teaddr);
  if (ret > 0)
   ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
  return ret;
 }

 dev_dbg(&sdata->dev->dev, "DISASSOC ACK received from %8phC\n", &teaddr);
 return 0;
}

static int
mac802154_send_association_resp_locked(struct ieee802154_sub_if_data *sdata,
           struct ieee802154_pan_device *target,
           struct ieee802154_assoc_resp_pl *assoc_resp_pl)
{
 u64 teaddr = swab64((__force u64)target->extended_addr);
 struct ieee802154_association_resp_frame frame = {};
 struct ieee802154_local *local = sdata->local;
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct sk_buff *skb;
 int ret;

 frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
 frame.mhr.fc.security_enabled = 0;
 frame.mhr.fc.frame_pending = 0;
 frame.mhr.fc.ack_request = 1; /* We always expect an ack here */
 frame.mhr.fc.intra_pan = 1;
 frame.mhr.fc.dest_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
 frame.mhr.fc.version = IEEE802154_2003_STD;
 frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
 frame.mhr.source.mode = IEEE802154_ADDR_LONG;
 frame.mhr.source.extended_addr = wpan_dev->extended_addr;
 frame.mhr.dest.mode = IEEE802154_ADDR_LONG;
 frame.mhr.dest.pan_id = wpan_dev->pan_id;
 frame.mhr.dest.extended_addr = target->extended_addr;
 frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
 frame.mac_pl.cmd_id = IEEE802154_CMD_ASSOCIATION_RESP;

 skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(*assoc_resp_pl),
   GFP_KERNEL);
 if (!skb)
  return -ENOBUFS;

 skb->dev = sdata->dev;

 ret = ieee802154_mac_cmd_push(skb, &frame, assoc_resp_pl,
          sizeof(*assoc_resp_pl));
 if (ret) {
  kfree_skb(skb);
  return ret;
 }

 ret = ieee802154_mlme_tx_locked(local, sdata, skb);
 if (ret) {
  dev_warn(&sdata->dev->dev,
    "No ASSOC RESP ACK received from %8phC\n", &teaddr);
  if (ret > 0)
   ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
  return ret;
 }

 return 0;
}

int mac802154_process_association_req(struct ieee802154_sub_if_data *sdata,
          struct sk_buff *skb)
{
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct ieee802154_addr *src = &mac_cb(skb)->source;
 struct ieee802154_addr *dest = &mac_cb(skb)->dest;
 struct ieee802154_assoc_resp_pl assoc_resp_pl = {};
 struct ieee802154_assoc_req_pl assoc_req_pl;
 struct ieee802154_pan_device *child, *exchild;
 struct ieee802154_addr tmp = {};
 u64 ceaddr;
 int ret;

 if (skb->len != sizeof(assoc_req_pl))
  return -EINVAL;

 if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING))
  return -EINVAL;

 if (unlikely(dest->pan_id != wpan_dev->pan_id))
  return -ENODEV;

 if (dest->mode == IEEE802154_EXTENDED_ADDRESSING &&
     unlikely(dest->extended_addr != wpan_dev->extended_addr))
  return -ENODEV;
 else if (dest->mode == IEEE802154_SHORT_ADDRESSING &&
   unlikely(dest->short_addr != wpan_dev->short_addr))
  return -ENODEV;

 if (wpan_dev->parent) {
  dev_dbg(&sdata->dev->dev,
   "Ignoring ASSOC REQ, not the PAN coordinator\n");
  return -ENODEV;
 }

 mutex_lock(&wpan_dev->association_lock);

 memcpy(&assoc_req_pl, skb->data, sizeof(assoc_req_pl));
 if (assoc_req_pl.assoc_type) {
  dev_err(&skb->dev->dev, "Fast associations not supported yet\n");
  ret = -EOPNOTSUPP;
  goto unlock;
 }

 child = kzalloc(sizeof(*child), GFP_KERNEL);
 if (!child) {
  ret = -ENOMEM;
  goto unlock;
 }

 child->extended_addr = src->extended_addr;
 child->mode = IEEE802154_EXTENDED_ADDRESSING;
 ceaddr = swab64((__force u64)child->extended_addr);

 if (wpan_dev->nchildren >= wpan_dev->max_associations) {
  if (!wpan_dev->max_associations)
   assoc_resp_pl.status = IEEE802154_PAN_ACCESS_DENIED;
  else
   assoc_resp_pl.status = IEEE802154_PAN_AT_CAPACITY;
  assoc_resp_pl.short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_BROADCAST);
  dev_dbg(&sdata->dev->dev,
   "Refusing ASSOC REQ from child %8phC, %s\n", &ceaddr,
   assoc_resp_pl.status == IEEE802154_PAN_ACCESS_DENIED ?
   "access denied" : "too many children");
 } else {
  assoc_resp_pl.status = IEEE802154_ASSOCIATION_SUCCESSFUL;
  if (assoc_req_pl.alloc_addr) {
   assoc_resp_pl.short_addr = cfg802154_get_free_short_addr(wpan_dev);
   child->mode = IEEE802154_SHORT_ADDRESSING;
  } else {
   assoc_resp_pl.short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
  }
  child->short_addr = assoc_resp_pl.short_addr;
  dev_dbg(&sdata->dev->dev,
   "Accepting ASSOC REQ from child %8phC, providing short address 0x%04x\n",
   &ceaddr, le16_to_cpu(child->short_addr));
 }

 ret = mac802154_send_association_resp_locked(sdata, child, &assoc_resp_pl);
 if (ret || assoc_resp_pl.status != IEEE802154_ASSOCIATION_SUCCESSFUL) {
  kfree(child);
  goto unlock;
 }

 dev_dbg(&sdata->dev->dev,
  "Successful association with new child %8phC\n", &ceaddr);

 /* Ensure this child is not already associated (might happen due to
 * retransmissions), in this case drop the ex structure.
 */
 tmp.mode = child->mode;
 tmp.extended_addr = child->extended_addr;
 exchild = cfg802154_device_is_child(wpan_dev, &tmp);
 if (exchild) {
  dev_dbg(&sdata->dev->dev,
   "Child %8phC was already known\n", &ceaddr);
  list_del(&exchild->node);
 }

 list_add(&child->node, &wpan_dev->children);
 wpan_dev->nchildren++;

unlock:
 mutex_unlock(&wpan_dev->association_lock);
 return ret;
}

int mac802154_process_disassociation_notif(struct ieee802154_sub_if_data *sdata,
        struct sk_buff *skb)
{
 struct ieee802154_addr *src = &mac_cb(skb)->source;
 struct ieee802154_addr *dest = &mac_cb(skb)->dest;
 struct wpan_dev *wpan_dev = &sdata->wpan_dev;
 struct ieee802154_pan_device *child;
 struct ieee802154_addr target;
 bool parent;
 u64 teaddr;

 if (skb->len != sizeof(u8))
  return -EINVAL;

 if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING))
  return -EINVAL;

 if (dest->mode == IEEE802154_EXTENDED_ADDRESSING &&
     unlikely(dest->extended_addr != wpan_dev->extended_addr))
  return -ENODEV;
 else if (dest->mode == IEEE802154_SHORT_ADDRESSING &&
   unlikely(dest->short_addr != wpan_dev->short_addr))
  return -ENODEV;

 if (dest->pan_id != wpan_dev->pan_id)
  return -ENODEV;

 target.mode = IEEE802154_EXTENDED_ADDRESSING;
 target.extended_addr = src->extended_addr;
 teaddr = swab64((__force u64)target.extended_addr);
 dev_dbg(&skb->dev->dev, "Processing DISASSOC NOTIF from %8phC\n", &teaddr);

 mutex_lock(&wpan_dev->association_lock);
 parent = cfg802154_device_is_parent(wpan_dev, &target);
 if (!parent)
  child = cfg802154_device_is_child(wpan_dev, &target);
 if (!parent && !child) {
  mutex_unlock(&wpan_dev->association_lock);
  return -EINVAL;
 }

 if (parent) {
  kfree(wpan_dev->parent);
  wpan_dev->parent = NULL;
 } else {
  list_del(&child->node);
  kfree(child);
  wpan_dev->nchildren--;
 }

 mutex_unlock(&wpan_dev->association_lock);

 return 0;
}