[PATCH wpan-next 06/11] mac802154: Handle disassociations

Miquel Raynal
2023-06-01T15:50:18Z

Devices may decide to disassociate from their coordinator for different
reasons (device turning off, coordinator signal strength too low, etc),
the MAC layer just has to send a disassociation notification.

If the ack of the disassociation notification is not received, the
device may consider itself disassociated anyway.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
net/ieee802154/pan.c | 2 +
net/mac802154/cfg.c | 102 +++++++++++++++++++++++++++++++++++
net/mac802154/ieee802154_i.h | 4 ++
net/mac802154/scan.c | 60 +++++++++++++++++++++
4 files changed, 168 insertions(+)

diff --git a/net/ieee802154/pan.c b/net/ieee802154/pan.c
index e2a12a42ba2b..477e8dad0cf0 100644
--- a/net/ieee802154/pan.c
+++ b/net/ieee802154/pan.c
@@ -49,6 +49,7 @@ bool cfg802154_device_is_parent(struct wpan_dev *wpan_dev,

return false;
}
+EXPORT_SYMBOL_GPL(cfg802154_device_is_parent);

struct ieee802154_pan_device *
cfg802154_device_is_child(struct wpan_dev *wpan_dev,
@@ -64,3 +65,4 @@ cfg802154_device_is_child(struct wpan_dev *wpan_dev,

return NULL;
}
+EXPORT_SYMBOL_GPL(cfg802154_device_is_child);
diff --git a/net/mac802154/cfg.c b/net/mac802154/cfg.c
index 89112d2bcee7..c27c05e825ff 100644
--- a/net/mac802154/cfg.c
+++ b/net/mac802154/cfg.c
@@ -386,6 +386,107 @@ static int mac802154_associate(struct wpan_phy *wpan_phy,
return ret;
}

+static int mac802154_disassociate_from_parent(struct wpan_phy *wpan_phy,
+ struct wpan_dev *wpan_dev)
+{
+ struct ieee802154_local *local = wpan_phy_priv(wpan_phy);
+ struct ieee802154_pan_device *child, *tmp;
+ struct ieee802154_sub_if_data *sdata;
+ u64 eaddr;
+ int ret;
+
+ sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(wpan_dev);
+
+ /* Start by disassociating all the children and preventing new ones to
+ * attempt associations.
+ */
+ list_for_each_entry_safe(child, tmp, &wpan_dev->children, node) {
+ ret = mac802154_send_disassociation_notif(sdata, child,
+ IEEE802154_COORD_WISHES_DEVICE_TO_LEAVE);
+ if (ret) {
+ eaddr = swab64((__force u64)child->extended_addr);
+ dev_err(&sdata->dev->dev,
+ "Disassociation with %8phC may have failed (%d)\n",
+ &eaddr, ret);
+ }
+
+ list_del(&child->node);
+ }
+
+ ret = mac802154_send_disassociation_notif(sdata, wpan_dev->parent,
+ IEEE802154_DEVICE_WISHES_TO_LEAVE);
+ if (ret) {
+ eaddr = swab64((__force u64)wpan_dev->parent->extended_addr);
+ dev_err(&sdata->dev->dev,
+ "Disassociation from %8phC may have failed (%d)\n",
+ &eaddr, ret);
+ }
+
+ ret = 0;
+
+ kfree(wpan_dev->parent);
+ wpan_dev->parent = NULL;
+ wpan_dev->association_generation++;
+ wpan_dev->pan_id = cpu_to_le16(IEEE802154_PAN_ID_BROADCAST);
+ wpan_dev->short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_BROADCAST);
+
+ if (local->hw.flags & IEEE802154_HW_AFILT) {
+ ret = drv_set_pan_id(local, wpan_dev->pan_id);
+ if (ret < 0)
+ return ret;
+
+ ret = drv_set_short_addr(local, wpan_dev->short_addr);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int mac802154_disassociate_child(struct wpan_phy *wpan_phy,
+ struct wpan_dev *wpan_dev,
+ struct ieee802154_pan_device *child)
+{
+ struct ieee802154_sub_if_data *sdata;
+ int ret;
+
+ sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(wpan_dev);
+
+ ret = mac802154_send_disassociation_notif(sdata, child,
+ IEEE802154_COORD_WISHES_DEVICE_TO_LEAVE);
+ if (ret)
+ return ret;
+
+ list_del(&child->node);
+ wpan_dev->association_generation++;
+ kfree(child);
+
+ return 0;
+}
+
+static int mac802154_disassociate(struct wpan_phy *wpan_phy,
+ struct wpan_dev *wpan_dev,
+ struct ieee802154_addr *target)
+{
+ u64 teaddr = swab64((__force u64)target->extended_addr);
+ struct ieee802154_pan_device *pan_device;
+
+ ASSERT_RTNL();
+
+ if (cfg802154_device_is_parent(wpan_dev, target))
+ return mac802154_disassociate_from_parent(wpan_phy, wpan_dev);
+
+ pan_device = cfg802154_device_is_child(wpan_dev, target);
+ if (pan_device)
+ return mac802154_disassociate_child(wpan_phy, wpan_dev,
+ pan_device);
+
+ dev_err(&wpan_dev->netdev->dev,
+ "Device %8phC is not associated with us\n", &teaddr);
+
+ return -EINVAL;
+}
+
#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
static void
ieee802154_get_llsec_table(struct wpan_phy *wpan_phy,
@@ -598,6 +699,7 @@ const struct cfg802154_ops mac802154_config_ops = {
.send_beacons = mac802154_send_beacons,
.stop_beacons = mac802154_stop_beacons,
.associate = mac802154_associate,
+ .disassociate = mac802154_disassociate,
#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 fff67676b400..92252f86c69c 100644
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -315,6 +315,10 @@ static inline bool mac802154_is_associating(struct ieee802154_local *local)
return test_bit(IEEE802154_IS_ASSOCIATING, &local->ongoing);
}

+int mac802154_send_disassociation_notif(struct ieee802154_sub_if_data *sdata,
+ struct ieee802154_pan_device *target,
+ u8 reason);
+
/* interface handling */
int ieee802154_iface_init(void);
void ieee802154_iface_exit(void);
diff --git a/net/mac802154/scan.c b/net/mac802154/scan.c
index 5dd50e1ce329..e2f2e1235ec6 100644
--- a/net/mac802154/scan.c
+++ b/net/mac802154/scan.c
@@ -637,3 +637,63 @@ int mac802154_process_association_resp(struct ieee802154_sub_if_data *sdata,

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;
+}
--
2.34.1