Implement the core hooks in order to provide the softMAC layer support
for scan requests and aborts.
Changing the channels is prohibited during the scan.
As transceiver enter in a promiscuous mode during scans, they might stop
checking frame validity so we ensure this gets done at mac level.
The implementation uses a workqueue triggered at a certain interval
depending on the symbol duration for the current channel and the
duration order provided.
Received beacons during a passive scanning procedure are processed and
either registered in the list of known PANs or the existing entry gets
updated accordingly.
Active scanning is not supported yet.
Co-developed-by: David Girault <david.girault@xxxxxxxxx>
Signed-off-by: David Girault <david.girault@xxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
---
include/linux/ieee802154.h | 4 +
include/net/mac802154.h | 14 ++
net/mac802154/Makefile | 2 +-
net/mac802154/cfg.c | 39 ++++++
net/mac802154/ieee802154_i.h | 22 +++
net/mac802154/main.c | 2 +-
net/mac802154/rx.c | 21 ++-
net/mac802154/scan.c | 259 +++++++++++++++++++++++++++++++++++
net/mac802154/tx.c | 3 +
net/mac802154/util.c | 26 ++++
10 files changed, 385 insertions(+), 7 deletions(-)
create mode 100644 net/mac802154/scan.c
diff --git a/include/linux/ieee802154.h b/include/linux/ieee802154.h
index 41178c87c43c..57bf5317338e 100644
--- a/include/linux/ieee802154.h
+++ b/include/linux/ieee802154.h
@@ -47,6 +47,10 @@
/* Duration in superframe order */
#define IEEE802154_MAX_SCAN_DURATION 14
#define IEEE802154_ACTIVE_SCAN_DURATION 15
+/* Superframe duration in slots */
+#define IEEE802154_SUPERFRAME_PERIOD 16
+/* Various periods expressed in symbols */
+#define IEEE802154_SLOT_PERIOD 60
#define IEEE802154_LIFS_PERIOD 40
#define IEEE802154_SIFS_PERIOD 12
#define IEEE802154_MAX_SIFS_FRAME_SIZE 18
diff --git a/include/net/mac802154.h b/include/net/mac802154.h
index 13798867b8d3..a2eec8786628 100644
--- a/include/net/mac802154.h
+++ b/include/net/mac802154.h
@@ -471,4 +471,18 @@ void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb,
void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb,
bool ifs_handling);
+/**
+ * ieee802154_queue_delayed_work - add work onto the mac802154 workqueue
+ *
+ * Drivers and mac802154 use this to queue delayed work onto the mac802154
+ * workqueue.
+ *
+ * @hw: the hardware struct for the interface we are adding work for
+ * @dwork: delayable work to queue onto the mac802154 workqueue
+ * @delay: number of jiffies to wait before queueing
+ */
+void ieee802154_queue_delayed_work(struct ieee802154_hw *hw,
+ struct delayed_work *dwork,
+ unsigned long delay);
+
#endif /* NET_MAC802154_H */
diff --git a/net/mac802154/Makefile b/net/mac802154/Makefile
index 4059295fdbf8..43d1347b37ee 100644
--- a/net/mac802154/Makefile
+++ b/net/mac802154/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_MAC802154) += mac802154.o
mac802154-objs := main.o rx.o tx.o mac_cmd.o mib.o \
- iface.o llsec.o util.o cfg.o trace.o
+ iface.o llsec.o util.o cfg.o scan.o trace.o
CFLAGS_trace.o := -I$(src)
diff --git a/net/mac802154/cfg.c b/net/mac802154/cfg.c
index e2900c9b788c..958b609b8c1b 100644
--- a/net/mac802154/cfg.c
+++ b/net/mac802154/cfg.c
@@ -117,6 +117,10 @@ ieee802154_set_channel(struct wpan_phy *wpan_phy, u8 page, u8 channel)
wpan_phy->current_channel == channel)
return 0;
+ /* Refuse to change channels during a scanning operation */
+ if (mac802154_scan_is_ongoing(local))
+ return -EBUSY;
+
ret = drv_set_channel(local, page, channel);
if (!ret) {
wpan_phy->current_page = page;
@@ -264,6 +268,39 @@ ieee802154_set_ackreq_default(struct wpan_phy *wpan_phy,
return 0;
}
+static int mac802154_trigger_scan(struct wpan_phy *wpan_phy,
+ struct cfg802154_scan_request *req)
+{
+ struct ieee802154_local *local = wpan_phy_priv(wpan_phy);
+ struct ieee802154_sub_if_data *sdata;
+ int ret;
+
+ sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(req->wpan_dev);
+
+ ASSERT_RTNL();
+
+ mutex_lock(&local->scan_lock);
+ ret = mac802154_trigger_scan_locked(sdata, req);
+ mutex_unlock(&local->scan_lock);
+
+ return ret;
+}
+
+static int mac802154_abort_scan(struct wpan_phy *wpan_phy,
+ struct wpan_dev *wpan_dev)
+{
+ struct ieee802154_local *local = wpan_phy_priv(wpan_phy);
+ int ret;
+
+ ASSERT_RTNL();
+
+ mutex_lock(&local->scan_lock);
+ ret = mac802154_abort_scan_locked(local);
+ mutex_unlock(&local->scan_lock);
+
+ return ret;
+}
+
#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
static void
ieee802154_get_llsec_table(struct wpan_phy *wpan_phy,
@@ -471,6 +508,8 @@ const struct cfg802154_ops mac802154_config_ops = {
.set_max_frame_retries = ieee802154_set_max_frame_retries,
.set_lbt_mode = ieee802154_set_lbt_mode,
.set_ackreq_default = ieee802154_set_ackreq_default,
+ .trigger_scan = mac802154_trigger_scan,
+ .abort_scan = mac802154_abort_scan,
#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
.get_llsec_table = ieee802154_get_llsec_table,
.lock_llsec_table = ieee802154_lock_llsec_table,
diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index 40195e2a6f1e..f7562f4cacdf 100644
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -48,6 +48,15 @@ struct ieee802154_local {
struct hrtimer ifs_timer;
+ /* Scanning */
+ struct mutex scan_lock;
+ atomic_t scanning;
+ __le64 scan_addr;
+ int scan_channel_idx;
+ struct cfg802154_scan_request __rcu *scan_req;
+ struct ieee802154_sub_if_data __rcu *scan_sdata;
+ struct delayed_work scan_work;
+
bool started;
bool suspended;
@@ -197,6 +206,19 @@ static inline bool mac802154_queue_is_stopped(struct ieee802154_local *local)
return atomic_read(&local->phy->hold_txs);
}
+/* scanning handling */
+void mac802154_scan_work(struct work_struct *work);
+int mac802154_trigger_scan_locked(struct ieee802154_sub_if_data *sdata,
+ struct cfg802154_scan_request *request);
+int mac802154_abort_scan_locked(struct ieee802154_local *local);
+int mac802154_scan_process_beacon(struct ieee802154_local *local,
+ struct sk_buff *skb);
+
+static inline bool mac802154_scan_is_ongoing(struct ieee802154_local *local)
+{
+ return atomic_read(&local->scanning);
+}
+
/* interface handling */
int ieee802154_iface_init(void);
void ieee802154_iface_exit(void);
diff --git a/net/mac802154/main.c b/net/mac802154/main.c
index 43fd4cc13b66..bd453b1c0223 100644
--- a/net/mac802154/main.c
+++ b/net/mac802154/main.c
@@ -90,6 +90,7 @@ ieee802154_alloc_hw(size_t priv_data_len, const struct ieee802154_ops *ops)
INIT_LIST_HEAD(&local->interfaces);
mutex_init(&local->iflist_mtx);
+ mutex_init(&local->scan_lock);
tasklet_setup(&local->tasklet, ieee802154_tasklet_handler);
@@ -97,7 +98,6 @@ ieee802154_alloc_hw(size_t priv_data_len, const struct ieee802154_ops *ops)
INIT_WORK(&local->sync_tx_work, ieee802154_xmit_sync_worker);
INIT_DELAYED_WORK(&local->scan_work, mac802154_scan_work);
- INIT_DELAYED_WORK(&local->beacons_work, mac802154_beacons_work);
/* init supported flags with 802.15.4 default ranges */
phy->supported.max_minbe = 8;
diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index b8ce84618a55..f2f3eca9bc20 100644
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -94,10 +94,15 @@ ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata,
switch (mac_cb(skb)->type) {
case IEEE802154_FC_TYPE_BEACON:
- case IEEE802154_FC_TYPE_ACK:
+ if (mac802154_scan_is_ongoing(sdata->local)) {
+ rc = mac802154_scan_process_beacon(sdata->local, skb);
+ if (!rc)
+ goto success;
+ }
+ goto fail;
case IEEE802154_FC_TYPE_MAC_CMD:
+ case IEEE802154_FC_TYPE_ACK:
goto fail;
-
case IEEE802154_FC_TYPE_DATA:
return ieee802154_deliver_skb(skb);
default:
@@ -109,6 +114,10 @@ ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata,
fail:
kfree_skb(skb);
return NET_RX_DROP;
+
+success:
+ kfree_skb(skb);
+ return NET_RX_SUCCESS;
}
static void
@@ -268,10 +277,12 @@ void ieee802154_rx(struct ieee802154_local *local, struct sk_buff *skb)
ieee802154_monitors_rx(local, skb);
- /* Check if transceiver doesn't validate the checksum.
- * If not we validate the checksum here.
+ /* Check if the transceiver doesn't validate the checksum, or if the
+ * check might have been disabled like during a scan. In these cases,
+ * we validate the checksum here.
*/
- if (local->hw.flags & IEEE802154_HW_RX_DROP_BAD_CKSUM) {
+ if (local->hw.flags & IEEE802154_HW_RX_DROP_BAD_CKSUM ||
+ mac802154_scan_is_ongoing(local)) {
crc = crc_ccitt(0, skb->data, skb->len);
if (crc) {
rcu_read_unlock();
diff --git a/net/mac802154/scan.c b/net/mac802154/scan.c
new file mode 100644
index 000000000000..3129cc95157a
--- /dev/null
+++ b/net/mac802154/scan.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * IEEE 802.15.4 scanning management
+ *
+ * Copyright (C) Qorvo, 2021
+ * Authors:
+ * - David Girault <david.girault@xxxxxxxxx>
+ * - Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
+ */
+
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/rtnetlink.h>
+#include <net/mac802154.h>
+
+#include "ieee802154_i.h"
+#include "driver-ops.h"
+#include "../ieee802154/nl802154.h"
+
+static bool mac802154_check_promiscuous(struct ieee802154_local *local)
+{
+ struct ieee802154_sub_if_data *sdata;
+ bool promiscuous_on = false;
+
+ /* Check if one subif is already in promiscuous mode. Since the list is
+ * protected by its own mutex, take it here to ensure no modification
+ * occurs during the check.
+ */
+ mutex_lock(&local->iflist_mtx);
+ list_for_each_entry(sdata, &local->interfaces, list) {
+ if (ieee802154_sdata_running(sdata) &&
+ sdata->wpan_dev.promiscuous_mode) {
+ /* At least one is in promiscuous mode */
+ promiscuous_on = true;
+ break;
+ }
+ }
+ mutex_unlock(&local->iflist_mtx);
+ return promiscuous_on;
+}
+
+static int mac802154_set_promiscuous_mode(struct ieee802154_local *local,
+ bool state)
+{
+ bool promiscuous_on = mac802154_check_promiscuous(local);
+ int ret;
+
+ if ((state && promiscuous_on) || (!state && !promiscuous_on))
+ return 0;
+
+ ret = drv_set_promiscuous_mode(local, state);
+ if (ret)
+ pr_err("Failed to %s promiscuous mode for SW scanning",
+ state ? "set" : "reset");
+
+ return ret;
+}
+
+static int mac802154_send_scan_done(struct ieee802154_local *local)
+{
+ struct cfg802154_registered_device *rdev;
+ struct cfg802154_scan_request *scan_req;
+ struct wpan_dev *wpan_dev;
+
+ scan_req = rcu_dereference_protected(local->scan_req,
+ lockdep_is_held(&local->scan_lock));
+ rdev = wpan_phy_to_rdev(scan_req->wpan_phy);
+ wpan_dev = scan_req->wpan_dev;
+
+ return nl802154_send_scan_done(rdev, wpan_dev);
+}
+
+static int mac802154_end_of_scan(struct ieee802154_local *local)
+{
+ drv_set_channel(local, local->phy->current_page,
+ local->phy->current_channel);
+ ieee802154_configure_durations(local->phy);
+ atomic_dec(&local->phy->hold_txs);
+ atomic_set(&local->scanning, 0);
+ mac802154_set_promiscuous_mode(local, false);
+ ieee802154_wake_queue(&local->hw);
+
+ return mac802154_send_scan_done(local);
+}
+
+int mac802154_abort_scan_locked(struct ieee802154_local *local)
+{
+ lockdep_assert_held(&local->scan_lock);
+
+ if (!mac802154_scan_is_ongoing(local))
+ return -ESRCH;
+
+ cancel_delayed_work(&local->scan_work);
+
+ return mac802154_end_of_scan(local);
+}
+
+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));
+}
+
+void mac802154_scan_work(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;
+ bool end_of_scan = false;
+ unsigned long chan;
+ int ret;
+
+ mutex_lock(&local->scan_lock);
+
+ if (!mac802154_scan_is_ongoing(local))
+ goto unlock_mutex;
+
+ sdata = rcu_dereference_protected(local->scan_sdata,
+ lockdep_is_held(&local->scan_lock));
+ scan_req = rcu_dereference_protected(local->scan_req,
+ lockdep_is_held(&local->scan_lock));
+
+ if (local->suspended || !ieee802154_sdata_running(sdata))
+ goto queue_work;
+
+ do {
+ chan = find_next_bit((const unsigned long *)&scan_req->channels,
+ IEEE802154_MAX_CHANNEL + 1,
+ local->scan_channel_idx + 1);
+
+ /* If there are no more channels left, complete the scan */
+ if (chan > IEEE802154_MAX_CHANNEL) {
+ end_of_scan = true;
+ goto unlock_mutex;
+ }
+
+ /* Channel switch cannot be made atomic so hide the chan number
+ * in order to prevent beacon processing during this timeframe.
+ */
+ local->scan_channel_idx = -1;
+ /* Bypass the stack on purpose */
+ ret = drv_set_channel(local, scan_req->page, chan);
+ local->scan_channel_idx = chan;
+ ieee802154_configure_durations(local->phy);
+ } while (ret);
+
+queue_work:
+ scan_duration = mac802154_scan_get_channel_time(scan_req->duration,
+ local->phy->symbol_duration);
+ pr_debug("Scan channel %lu of page %u for %ums\n",
+ chan, scan_req->page, jiffies_to_msecs(scan_duration));
+ ieee802154_queue_delayed_work(&local->hw, &local->scan_work,
+ scan_duration);
+
+unlock_mutex:
+ if (end_of_scan)
+ mac802154_end_of_scan(local);
+
+ mutex_unlock(&local->scan_lock);
+}
+
+int mac802154_trigger_scan_locked(struct ieee802154_sub_if_data *sdata,
+ struct cfg802154_scan_request *request)
+{
+ struct ieee802154_local *local = sdata->local;
+ int ret;
+
+ lockdep_assert_held(&local->scan_lock);
+
+ if (mac802154_scan_is_ongoing(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);
+ rcu_assign_pointer(local->scan_sdata, sdata);
+
+ /* Configure scan_addr to use net_device addr or random */
+ if (request->flags & NL802154_SCAN_FLAG_RANDOM_ADDR)
+ get_random_bytes(&local->scan_addr, sizeof(local->scan_addr));
+ else
+ local->scan_addr = cpu_to_le64(get_unaligned_be64(sdata->dev->dev_addr));
+
+ local->scan_channel_idx = -1;
+ atomic_set(&local->scanning, 1);
+
+ /* Software scanning requires to set promiscuous mode, so we need to
+ * pause the Tx queue
+ */
+ atomic_inc(&local->phy->hold_txs);
+ ieee802154_stop_queue(&local->hw);
+ ieee802154_sync_tx(local);
+
+ ret = mac802154_set_promiscuous_mode(local, true);
+ if (ret)
+ return mac802154_end_of_scan(local);
+
+ ieee802154_queue_delayed_work(&local->hw, &local->scan_work, 0);
+
+ return 0;
+}
+
+int mac802154_scan_process_beacon(struct ieee802154_local *local,
+ struct sk_buff *skb)
+{
+ struct ieee802154_beacon_hdr *bh = (void *)skb->data;
+ struct ieee802154_addr *src = &mac_cb(skb)->source;
+ struct cfg802154_scan_request *scan_req;
+ struct ieee802154_pan_desc desc = {};
+ int ret;
+
+ /* Check the validity of the frame length */
+ if (skb->len < sizeof(*bh))
+ return -EINVAL;
+
+ if (unlikely(src->mode == IEEE802154_ADDR_NONE))
+ return -EINVAL;
+
+ if (unlikely(!bh->pan_coordinator))
+ return -ENODEV;
+
+ scan_req = rcu_dereference(local->scan_req);
+ if (unlikely(!scan_req))
+ return -EINVAL;
+
+ if (unlikely(local->scan_channel_idx < 0)) {
+ pr_info("Dropping beacon received during channel change\n");
+ return 0;
+ }
+
+ pr_debug("Beacon received on channel %d of page %d\n",
+ local->scan_channel_idx, scan_req->page);
+
+ /* Parse beacon and create PAN information */
+ desc.coord = src;
+ desc.page = scan_req->page;
+ desc.channel = local->scan_channel_idx;
+ desc.link_quality = mac_cb(skb)->lqi;
+ desc.superframe_spec = get_unaligned_le16(skb->data);
+ desc.gts_permit = bh->gts_permit;
+
+ /* Create or update the PAN entry in the management layer */
+ ret = cfg802154_record_pan(local->phy, &desc);
+ if (ret) {
+ pr_err("Failed to save PAN descriptor\n");
+ return ret;
+ }
+
+ return 0;
+}
diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index 334843f66ec4..1849e5cb5945 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -58,6 +58,9 @@ ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
struct net_device *dev = skb->dev;
int ret;
+ if (unlikely(mac802154_scan_is_ongoing(local)))
+ return NETDEV_TX_BUSY;
+
if (!(local->hw.flags & IEEE802154_HW_TX_OMIT_CKSUM)) {
struct sk_buff *nskb;
u16 crc;
diff --git a/net/mac802154/util.c b/net/mac802154/util.c
index 230fe3390df7..5642a45df548 100644
--- a/net/mac802154/util.c
+++ b/net/mac802154/util.c
@@ -100,3 +100,29 @@ void ieee802154_stop_device(struct ieee802154_local *local)
hrtimer_cancel(&local->ifs_timer);
drv_stop(local);
}
+
+/* Nothing should have been stuffed into the workqueue during
+ * the suspend->resume cycle.
+ */
+static bool ieee802154_can_queue_work(struct ieee802154_local *local)
+{
+ if (local->suspended) {
+ pr_warn("queueing ieee802154 work while suspended\n");
+ return false;
+ }
+
+ return true;
+}
+
+void ieee802154_queue_delayed_work(struct ieee802154_hw *hw,
+ struct delayed_work *dwork,
+ unsigned long delay)
+{
+ struct ieee802154_local *local = hw_to_local(hw);
+
+ if (!ieee802154_can_queue_work(local))
+ return;
+
+ queue_delayed_work(local->workqueue, dwork, delay);
+}
+EXPORT_SYMBOL(ieee802154_queue_delayed_work);
--
2.27.0
