mac80211: use the new drop reasons infrastructure

It can be really hard to analyse or debug why packets are
going missing in mac80211, so add the needed infrastructure
to use use the new per-subsystem drop reasons.

We actually use two drop reason subsystems here because of
the different handling of frames that are dropped but still
go to monitor for old versions of hostapd, and those that
are just completely unusable (e.g. crypto failed.)

Annotate a few reasons here just to illustrate this, we'll
need to go through and annotate more of them later.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index ddf2b7811c55..55cdfaef0f5d 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -22,6 +22,7 @@
 #include <linux/bitmap.h>
 #include <linux/inetdevice.h>
 #include <net/net_namespace.h>
+#include <net/dropreason.h>
 #include <net/cfg80211.h>
 #include <net/addrconf.h>
 
@@ -1542,6 +1543,28 @@ void ieee80211_free_hw(struct ieee80211_hw *hw)
 }
 EXPORT_SYMBOL(ieee80211_free_hw);
 
+static const char * const drop_reasons_monitor[] = {
+#define V(x)	#x,
+	[0] = "RX_DROP_MONITOR",
+	MAC80211_DROP_REASONS_MONITOR(V)
+};
+
+static struct drop_reason_list drop_reason_list_monitor = {
+	.reasons = drop_reasons_monitor,
+	.n_reasons = ARRAY_SIZE(drop_reasons_monitor),
+};
+
+static const char * const drop_reasons_unusable[] = {
+	[0] = "RX_DROP_UNUSABLE",
+	MAC80211_DROP_REASONS_UNUSABLE(V)
+#undef V
+};
+
+static struct drop_reason_list drop_reason_list_unusable = {
+	.reasons = drop_reasons_unusable,
+	.n_reasons = ARRAY_SIZE(drop_reasons_unusable),
+};
+
 static int __init ieee80211_init(void)
 {
 	struct sk_buff *skb;
@@ -1559,6 +1582,11 @@ static int __init ieee80211_init(void)
 	if (ret)
 		goto err_netdev;
 
+	drop_reasons_register_subsys(SKB_DROP_REASON_SUBSYS_MAC80211_MONITOR,
+				     &drop_reason_list_monitor);
+	drop_reasons_register_subsys(SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE,
+				     &drop_reason_list_unusable);
+
 	return 0;
  err_netdev:
 	rc80211_minstrel_exit();
@@ -1574,6 +1602,9 @@ static void __exit ieee80211_exit(void)
 
 	ieee80211_iface_exit();
 
+	drop_reasons_unregister_subsys(SKB_DROP_REASON_SUBSYS_MAC80211_MONITOR);
+	drop_reasons_unregister_subsys(SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE);
+
 	rcu_barrier();
 }