diff options
Diffstat (limited to 'net/mac802154/scan.c')
-rw-r--r-- | net/mac802154/scan.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/net/mac802154/scan.c b/net/mac802154/scan.c new file mode 100644 index 000000000000..56056b9c93c1 --- /dev/null +++ b/net/mac802154/scan.c @@ -0,0 +1,288 @@ +// 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" + +/* 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; + kfree_rcu(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; +} + +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; + 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_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; + } + + 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; + + /* TODO: support other scanning type */ + if (request->type != NL802154_SCAN_PASSIVE) + 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); + + 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; +} |