mac80211: allow drivers to access IPv6 information

To be able to implement NS response offloading (in
regular operation or while in WoWLAN) drivers need
to know the IPv6 addresses assigned to interfaces.
Implement an IPv6 notifier in mac80211 to call the
driver when addresses change.

Unlike for IPv4, implement it as a callback rather
than as a list in the BSS configuration, that is
more flexible.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -2497,6 +2497,9 @@ enum ieee80211_rate_control_changed {
  *	driver's resume function returned 1, as this is just like an "inline"
  *	hardware restart. This callback may sleep.
  *
+ * @ipv6_addr_change: IPv6 address assignment on the given interface changed.
+ *	Currently, this is only called for managed or P2P client interfaces.
+ *	This callback is optional; it must not sleep.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw,
@@ -2672,6 +2675,12 @@ struct ieee80211_ops {
 				     struct ieee80211_chanctx_conf *ctx);
 
 	void (*restart_complete)(struct ieee80211_hw *hw);
+
+#if IS_ENABLED(CONFIG_IPV6)
+	void (*ipv6_addr_change)(struct ieee80211_hw *hw,
+				 struct ieee80211_vif *vif,
+				 struct inet6_dev *idev);
+#endif
 };
 
 /**

net/mac80211/driver-ops.h

@@ -1036,4 +1036,16 @@ drv_set_default_unicast_key(struct ieee80211_local *local,
 	trace_drv_return_void(local);
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
+static inline void drv_ipv6_addr_change(struct ieee80211_local *local,
+					struct ieee80211_sub_if_data *sdata,
+					struct inet6_dev *idev)
+{
+	trace_drv_ipv6_addr_change(local, sdata);
+	if (local->ops->ipv6_addr_change)
+		local->ops->ipv6_addr_change(&local->hw, &sdata->vif, idev);
+	trace_drv_return_void(local);
+}
+#endif
+
 #endif /* __MAC80211_DRIVER_OPS */

net/mac80211/ieee80211_i.h

@@ -1127,6 +1127,7 @@ struct ieee80211_local {
 	struct timer_list dynamic_ps_timer;
 	struct notifier_block network_latency_notifier;
 	struct notifier_block ifa_notifier;
+	struct notifier_block ifa6_notifier;
 
 	/*
 	 * The dynamic ps timeout configured from user space via WEXT -

net/mac80211/main.c

@@ -23,6 +23,7 @@
 #include <linux/inetdevice.h>
 #include <net/net_namespace.h>
 #include <net/cfg80211.h>
+#include <net/addrconf.h>
 
 #include "ieee80211_i.h"
 #include "driver-ops.h"
@@ -369,6 +370,37 @@ static int ieee80211_ifa_changed(struct notifier_block *nb,
 }
 #endif
 
+#if IS_ENABLED(CONFIG_IPV6)
+static int ieee80211_ifa6_changed(struct notifier_block *nb,
+				  unsigned long data, void *arg)
+{
+	struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)arg;
+	struct inet6_dev *idev = ifa->idev;
+	struct net_device *ndev = ifa->idev->dev;
+	struct ieee80211_local *local =
+		container_of(nb, struct ieee80211_local, ifa6_notifier);
+	struct wireless_dev *wdev = ndev->ieee80211_ptr;
+	struct ieee80211_sub_if_data *sdata;
+
+	/* Make sure it's our interface that got changed */
+	if (!wdev || wdev->wiphy != local->hw.wiphy)
+		return NOTIFY_DONE;
+
+	sdata = IEEE80211_DEV_TO_SUB_IF(ndev);
+
+	/*
+	 * For now only support station mode. This is mostly because
+	 * doing AP would have to handle AP_VLAN in some way ...
+	 */
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return NOTIFY_DONE;
+
+	drv_ipv6_addr_change(local, sdata, idev);
+
+	return NOTIFY_DONE;
+}
+#endif
+
 static int ieee80211_napi_poll(struct napi_struct *napi, int budget)
 {
 	struct ieee80211_local *local =
@@ -977,12 +1009,25 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 		goto fail_ifa;
 #endif
 
+#if IS_ENABLED(CONFIG_IPV6)
+	local->ifa6_notifier.notifier_call = ieee80211_ifa6_changed;
+	result = register_inet6addr_notifier(&local->ifa6_notifier);
+	if (result)
+		goto fail_ifa6;
+#endif
+
 	netif_napi_add(&local->napi_dev, &local->napi, ieee80211_napi_poll,
 			local->hw.napi_weight);
 
 	return 0;
 
+#if IS_ENABLED(CONFIG_IPV6)
+ fail_ifa6:
 #ifdef CONFIG_INET
+	unregister_inetaddr_notifier(&local->ifa_notifier);
+#endif
+#endif
+#if defined(CONFIG_INET) || defined(CONFIG_IPV6)
  fail_ifa:
 	pm_qos_remove_notifier(PM_QOS_NETWORK_LATENCY,
 			       &local->network_latency_notifier);
@@ -1018,6 +1063,9 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 #ifdef CONFIG_INET
 	unregister_inetaddr_notifier(&local->ifa_notifier);
 #endif
+#if IS_ENABLED(CONFIG_IPV6)
+	unregister_inet6addr_notifier(&local->ifa6_notifier);
+#endif
 
 	rtnl_lock();
 

net/mac80211/trace.h

@@ -1437,6 +1437,14 @@ DEFINE_EVENT(local_only_evt, drv_restart_complete,
 	TP_ARGS(local)
 );
 
+#if IS_ENABLED(CONFIG_IPV6)
+DEFINE_EVENT(local_sdata_evt, drv_ipv6_addr_change,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata),
+	TP_ARGS(local, sdata)
+);
+#endif
+
 /*
  * Tracing for API calls that drivers call.
  */