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>
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index e9f9591..2a2c2e2 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -1437,6 +1437,14 @@
 	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.
  */