[PATCH wpan-next 08/11] ieee802154: Add support for limiting the number of associated devices

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

Coordinators may refuse associations. We need a user input for
that. Let's add a new netlink command which can provide a maximum number
of devices we accept to associate with as a first step. Later, we could
also forward the request to userspace and check whether the association
should be accepted or not.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
include/net/cfg802154.h | 8 ++++++++
include/net/nl802154.h | 2 ++
net/ieee802154/core.c | 1 +
net/ieee802154/nl802154.c | 28 ++++++++++++++++++++++++++++
net/ieee802154/pan.c | 8 ++++++++
5 files changed, 47 insertions(+)

diff --git a/include/net/cfg802154.h b/include/net/cfg802154.h
index 4404072365e7..d7583598b290 100644
--- a/include/net/cfg802154.h
+++ b/include/net/cfg802154.h
@@ -506,6 +506,7 @@ struct wpan_dev {
struct ieee802154_pan_device *parent;
struct list_head children;
unsigned int association_generation;
+ unsigned int max_associations;
};

#define to_phy(_dev) container_of(_dev, struct wpan_phy, dev)
@@ -582,6 +583,13 @@ struct ieee802154_pan_device *
cfg802154_device_is_child(struct wpan_dev *wpan_dev,
struct ieee802154_addr *target);

+/**
+ * cfg802154_set_max_associations - Limit the number of future associations
+ * @wpan_dev: the wpan device
+ * @max: the maximum number of devices we accept to associate
+ */
+void cfg802154_set_max_associations(struct wpan_dev *wpan_dev, unsigned int max);
+
/**
* cfg802154_get_free_short_addr - Get a free address among the known devices
* @wpan_dev: the wpan device
diff --git a/include/net/nl802154.h b/include/net/nl802154.h
index 8a47c14c72f0..8b26faae49e8 100644
--- a/include/net/nl802154.h
+++ b/include/net/nl802154.h
@@ -80,6 +80,7 @@ enum nl802154_commands {
NL802154_CMD_STOP_BEACONS,
NL802154_CMD_ASSOCIATE,
NL802154_CMD_DISASSOCIATE,
+ NL802154_CMD_SET_MAX_ASSOCIATIONS,

/* add new commands above here */

@@ -149,6 +150,7 @@ enum nl802154_attrs {
NL802154_ATTR_SCAN_DURATION,
NL802154_ATTR_SCAN_DONE_REASON,
NL802154_ATTR_BEACON_INTERVAL,
+ NL802154_ATTR_MAX_ASSOCIATIONS,

/* add attributes here, update the policy in nl802154.c */

diff --git a/net/ieee802154/core.c b/net/ieee802154/core.c
index 39674db64336..65bb656db9b4 100644
--- a/net/ieee802154/core.c
+++ b/net/ieee802154/core.c
@@ -297,6 +297,7 @@ static int cfg802154_netdev_notifier_call(struct notifier_block *nb,
rdev->devlist_generation++;
mutex_init(&wpan_dev->association_lock);
INIT_LIST_HEAD(&wpan_dev->children);
+ wpan_dev->max_associations = SZ_16K;

wpan_dev->netdev = dev;
break;
diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 5820fe425ddd..e16e57fc34d0 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -234,6 +234,7 @@ static const struct nla_policy nl802154_policy[NL802154_ATTR_MAX+1] = {
NL802154_SCAN_DONE_REASON_ABORTED),
[NL802154_ATTR_BEACON_INTERVAL] =
NLA_POLICY_MAX(NLA_U8, IEEE802154_ACTIVE_SCAN_DURATION),
+ [NL802154_ATTR_MAX_ASSOCIATIONS] = { .type = NLA_U32 },

#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
[NL802154_ATTR_SEC_ENABLED] = { .type = NLA_U8, },
@@ -1696,6 +1697,26 @@ static int nl802154_disassociate(struct sk_buff *skb, struct genl_info *info)
return 0;
}

+static int nl802154_set_max_associations(struct sk_buff *skb, struct genl_info *info)
+{
+ struct net_device *dev = info->user_ptr[1];
+ struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
+ unsigned int max_assoc;
+
+ if (!info->attrs[NL802154_ATTR_MAX_ASSOCIATIONS]) {
+ NL_SET_ERR_MSG(info->extack, "No maximum number of association given");
+ return -EINVAL;
+ }
+
+ max_assoc = nla_get_u32(info->attrs[NL802154_ATTR_MAX_ASSOCIATIONS]);
+
+ mutex_lock(&wpan_dev->association_lock);
+ cfg802154_set_max_associations(wpan_dev, max_assoc);
+ mutex_unlock(&wpan_dev->association_lock);
+
+ return 0;
+}
+
#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
static const struct nla_policy nl802154_dev_addr_policy[NL802154_DEV_ADDR_ATTR_MAX + 1] = {
[NL802154_DEV_ADDR_ATTR_PAN_ID] = { .type = NLA_U16 },
@@ -2833,6 +2854,13 @@ static const struct genl_ops nl802154_ops[] = {
NL802154_FLAG_CHECK_NETDEV_UP |
NL802154_FLAG_NEED_RTNL,
},
+ {
+ .cmd = NL802154_CMD_SET_MAX_ASSOCIATIONS,
+ .doit = nl802154_set_max_associations,
+ .flags = GENL_ADMIN_PERM,
+ .internal_flags = NL802154_FLAG_NEED_NETDEV |
+ NL802154_FLAG_NEED_RTNL,
+ },
#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
{
.cmd = NL802154_CMD_SET_SEC_PARAMS,
diff --git a/net/ieee802154/pan.c b/net/ieee802154/pan.c
index 7756906c201d..138a55847d78 100644
--- a/net/ieee802154/pan.c
+++ b/net/ieee802154/pan.c
@@ -93,3 +93,11 @@ __le16 cfg802154_get_free_short_addr(struct wpan_dev *wpan_dev)
return addr;
}
EXPORT_SYMBOL_GPL(cfg802154_get_free_short_addr);
+
+void cfg802154_set_max_associations(struct wpan_dev *wpan_dev, unsigned int max)
+{
+ lockdep_assert_held(&wpan_dev->association_lock);
+
+ wpan_dev->max_associations = max;
+}
+EXPORT_SYMBOL_GPL(cfg802154_set_max_associations);
--
2.34.1