[net-next,v4,3/3] mac80211: use the new drop reasons infrastructure

diff --git a/include/net/dropreason.h b/include/net/dropreason.h
index f0f2378dbed0..685fb37df8e8 100644
--- a/include/net/dropreason.h
+++ b/include/net/dropreason.h
@@ -11,6 +11,18 @@  enum skb_drop_reason_subsys {
 	/** @SKB_DROP_REASON_SUBSYS_CORE: core drop reasons defined above */
 	SKB_DROP_REASON_SUBSYS_CORE,
 
+	/**
+	 * @SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE: mac80211 drop reasons
+	 * for unusable frames, see net/mac80211/drop.h
+	 */
+	SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE,
+
+	/**
+	 * @SKB_DROP_REASON_SUBSYS_MAC80211_MONITOR: mac80211 drop reasons
+	 * for frames still going to monitor, see net/mac80211/drop.h
+	 */
+	SKB_DROP_REASON_SUBSYS_MAC80211_MONITOR,
+
 	/** @SKB_DROP_REASON_SUBSYS_NUM: number of subsystems defined */
 	SKB_DROP_REASON_SUBSYS_NUM
 };
diff --git a/net/mac80211/drop.h b/net/mac80211/drop.h
new file mode 100644
index 000000000000..49dc809cab29
--- /dev/null
+++ b/net/mac80211/drop.h
@@ -0,0 +1,56 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * mac80211 drop reason list
+ *
+ * Copyright (C) 2023 Intel Corporation
+ */
+
+#ifndef MAC80211_DROP_H
+#define MAC80211_DROP_H
+#include <net/dropreason.h>
+
+typedef unsigned int __bitwise ieee80211_rx_result;
+
+#define MAC80211_DROP_REASONS_MONITOR(R)	\
+	R(RX_DROP_M_UNEXPECTED_4ADDR_FRAME)	\
+	R(RX_DROP_M_BAD_BCN_KEYIDX)		\
+	R(RX_DROP_M_BAD_MGMT_KEYIDX)		\
+/* this line for the trailing \ - add before this */
+
+#define MAC80211_DROP_REASONS_UNUSABLE(R)	\
+	R(RX_DROP_U_MIC_FAIL)			\
+	R(RX_DROP_U_REPLAY)			\
+	R(RX_DROP_U_BAD_MMIE)			\
+/* this line for the trailing \ - add before this */
+
+/* having two enums allows for checking ieee80211_rx_result use with sparse */
+enum ___mac80211_drop_reason {
+/* if we get to the end of handlers with RX_CONTINUE this will be the reason */
+	___RX_CONTINUE	= SKB_CONSUMED,
+
+/* this never gets used as an argument to kfree_skb_reason() */
+	___RX_QUEUED	= SKB_NOT_DROPPED_YET,
+
+#define ENUM(x) ___ ## x,
+	___RX_DROP_MONITOR = SKB_DROP_REASON_SUBSYS_MAC80211_MONITOR <<
+		SKB_DROP_REASON_SUBSYS_SHIFT,
+	MAC80211_DROP_REASONS_MONITOR(ENUM)
+
+	___RX_DROP_UNUSABLE = SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE <<
+		SKB_DROP_REASON_SUBSYS_SHIFT,
+	MAC80211_DROP_REASONS_UNUSABLE(ENUM)
+#undef ENUM
+};
+
+enum mac80211_drop_reason {
+	RX_CONTINUE	 = (__force ieee80211_rx_result)___RX_CONTINUE,
+	RX_QUEUED	 = (__force ieee80211_rx_result)___RX_QUEUED,
+	RX_DROP_MONITOR	 = (__force ieee80211_rx_result)___RX_DROP_MONITOR,
+	RX_DROP_UNUSABLE = (__force ieee80211_rx_result)___RX_DROP_UNUSABLE,
+#define DEF(x) x = (__force ieee80211_rx_result)___ ## x,
+	MAC80211_DROP_REASONS_MONITOR(DEF)
+	MAC80211_DROP_REASONS_UNUSABLE(DEF)
+#undef DEF
+};
+
+#endif /* MAC80211_DROP_H */
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9b7e184430b8..a0a7839cb961 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -33,6 +33,7 @@ 
 #include "key.h"
 #include "sta_info.h"
 #include "debug.h"
+#include "drop.h"
 
 extern const struct cfg80211_ops mac80211_config_ops;
 
@@ -170,13 +171,6 @@  struct ieee80211_tx_data {
 	unsigned int flags;
 };
 
-
-typedef unsigned __bitwise ieee80211_rx_result;
-#define RX_CONTINUE		((__force ieee80211_rx_result) 0u)
-#define RX_DROP_UNUSABLE	((__force ieee80211_rx_result) 1u)
-#define RX_DROP_MONITOR		((__force ieee80211_rx_result) 2u)
-#define RX_QUEUED		((__force ieee80211_rx_result) 3u)
-
 /**
  * enum ieee80211_packet_rx_flags - packet RX flags
  * @IEEE80211_RX_AMSDU: a-MSDU packet
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();
 }
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index db3451f5f2fb..58222c077898 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1826,7 +1826,7 @@  ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
 				cfg80211_rx_unexpected_4addr_frame(
 					rx->sdata->dev, sta->sta.addr,
 					GFP_ATOMIC);
-			return RX_DROP_MONITOR;
+			return RX_DROP_M_UNEXPECTED_4ADDR_FRAME;
 		}
 		/*
 		 * Update counter and free packet here to avoid
@@ -1961,7 +1961,7 @@  ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 				cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
 							     skb->data,
 							     skb->len);
-			return RX_DROP_MONITOR; /* unexpected BIP keyidx */
+			return RX_DROP_M_BAD_BCN_KEYIDX;
 		}
 
 		rx->key = ieee80211_rx_get_bigtk(rx, mmie_keyidx);
@@ -1975,7 +1975,7 @@  ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 
 		if (mmie_keyidx < NUM_DEFAULT_KEYS ||
 		    mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
-			return RX_DROP_MONITOR; /* unexpected BIP keyidx */
+			return RX_DROP_M_BAD_MGMT_KEYIDX; /* unexpected BIP keyidx */
 		if (rx->link_sta) {
 			if (ieee80211_is_group_privacy_action(skb) &&
 			    test_sta_flag(rx->sta, WLAN_STA_MFP))
@@ -3960,7 +3960,8 @@  ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
 }
 
 static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx,
-					struct ieee80211_rate *rate)
+					struct ieee80211_rate *rate,
+					ieee80211_rx_result reason)
 {
 	struct ieee80211_sub_if_data *sdata;
 	struct ieee80211_local *local = rx->local;
@@ -4024,42 +4025,38 @@  static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx,
 	}
 
  out_free_skb:
-	dev_kfree_skb(skb);
+	kfree_skb_reason(skb, (__force u32)reason);
 }
 
 static void ieee80211_rx_handlers_result(struct ieee80211_rx_data *rx,
 					 ieee80211_rx_result res)
 {
-	switch (res) {
-	case RX_DROP_MONITOR:
-		I802_DEBUG_INC(rx->sdata->local->rx_handlers_drop);
-		if (rx->sta)
-			rx->link_sta->rx_stats.dropped++;
-		fallthrough;
-	case RX_CONTINUE: {
-		struct ieee80211_rate *rate = NULL;
-		struct ieee80211_supported_band *sband;
-		struct ieee80211_rx_status *status;
+	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_rate *rate = NULL;
 
-		status = IEEE80211_SKB_RXCB((rx->skb));
-
-		sband = rx->local->hw.wiphy->bands[status->band];
-		if (status->encoding == RX_ENC_LEGACY)
-			rate = &sband->bitrates[status->rate_idx];
-
-		ieee80211_rx_cooked_monitor(rx, rate);
-		break;
-		}
-	case RX_DROP_UNUSABLE:
-		I802_DEBUG_INC(rx->sdata->local->rx_handlers_drop);
-		if (rx->sta)
-			rx->link_sta->rx_stats.dropped++;
-		dev_kfree_skb(rx->skb);
-		break;
-	case RX_QUEUED:
+	if (res == RX_QUEUED) {
 		I802_DEBUG_INC(rx->sdata->local->rx_handlers_queued);
-		break;
+		return;
 	}
+
+	if (res != RX_CONTINUE) {
+		I802_DEBUG_INC(rx->sdata->local->rx_handlers_drop);
+		if (rx->sta)
+			rx->link_sta->rx_stats.dropped++;
+	}
+
+	if (u32_get_bits((__force u32)res, SKB_DROP_REASON_SUBSYS_MASK) ==
+			SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE) {
+		kfree_skb_reason(rx->skb, (__force u32)res);
+		return;
+	}
+
+	sband = rx->local->hw.wiphy->bands[status->band];
+	if (status->encoding == RX_ENC_LEGACY)
+		rate = &sband->bitrates[status->rate_idx];
+
+	ieee80211_rx_cooked_monitor(rx, rate, res);
 }
 
 static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx,
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 20f742b5503b..4133496da378 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -550,7 +550,7 @@  ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx,
 		if (res < 0 ||
 		    (!res && !(status->flag & RX_FLAG_ALLOW_SAME_PN))) {
 			key->u.ccmp.replays++;
-			return RX_DROP_UNUSABLE;
+			return RX_DROP_U_REPLAY;
 		}
 
 		if (!(status->flag & RX_FLAG_DECRYPTED)) {
@@ -564,7 +564,7 @@  ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx,
 				    skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
 				    data_len,
 				    skb->data + skb->len - mic_len))
-				return RX_DROP_UNUSABLE;
+				return RX_DROP_U_MIC_FAIL;
 		}
 
 		memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
@@ -746,7 +746,7 @@  ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx)
 		if (res < 0 ||
 		    (!res && !(status->flag & RX_FLAG_ALLOW_SAME_PN))) {
 			key->u.gcmp.replays++;
-			return RX_DROP_UNUSABLE;
+			return RX_DROP_U_REPLAY;
 		}
 
 		if (!(status->flag & RX_FLAG_DECRYPTED)) {
@@ -761,7 +761,7 @@  ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx)
 				    data_len,
 				    skb->data + skb->len -
 				    IEEE80211_GCMP_MIC_LEN))
-				return RX_DROP_UNUSABLE;
+				return RX_DROP_U_MIC_FAIL;
 		}
 
 		memcpy(key->u.gcmp.rx_pn[queue], pn, IEEE80211_GCMP_PN_LEN);
@@ -930,13 +930,13 @@  ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 		(skb->data + skb->len - sizeof(*mmie));
 	if (mmie->element_id != WLAN_EID_MMIE ||
 	    mmie->length != sizeof(*mmie) - 2)
-		return RX_DROP_UNUSABLE; /* Invalid MMIE */
+		return RX_DROP_U_BAD_MMIE; /* Invalid MMIE */
 
 	bip_ipn_swap(ipn, mmie->sequence_number);
 
 	if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 		key->u.aes_cmac.replays++;
-		return RX_DROP_UNUSABLE;
+		return RX_DROP_U_REPLAY;
 	}
 
 	if (!(status->flag & RX_FLAG_DECRYPTED)) {
@@ -946,7 +946,7 @@  ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 				   skb->data + 24, skb->len - 24, mic);
 		if (crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 			key->u.aes_cmac.icverrors++;
-			return RX_DROP_UNUSABLE;
+			return RX_DROP_U_MIC_FAIL;
 		}
 	}
 
@@ -986,7 +986,7 @@  ieee80211_crypto_aes_cmac_256_decrypt(struct ieee80211_rx_data *rx)
 
 	if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
 		key->u.aes_cmac.replays++;
-		return RX_DROP_UNUSABLE;
+		return RX_DROP_U_REPLAY;
 	}
 
 	if (!(status->flag & RX_FLAG_DECRYPTED)) {
@@ -996,7 +996,7 @@  ieee80211_crypto_aes_cmac_256_decrypt(struct ieee80211_rx_data *rx)
 				       skb->data + 24, skb->len - 24, mic);
 		if (crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 			key->u.aes_cmac.icverrors++;
-			return RX_DROP_UNUSABLE;
+			return RX_DROP_U_MIC_FAIL;
 		}
 	}
 
@@ -1079,13 +1079,13 @@  ieee80211_crypto_aes_gmac_decrypt(struct ieee80211_rx_data *rx)
 		(skb->data + skb->len - sizeof(*mmie));
 	if (mmie->element_id != WLAN_EID_MMIE ||
 	    mmie->length != sizeof(*mmie) - 2)
-		return RX_DROP_UNUSABLE; /* Invalid MMIE */
+		return RX_DROP_U_BAD_MMIE; /* Invalid MMIE */
 
 	bip_ipn_swap(ipn, mmie->sequence_number);
 
 	if (memcmp(ipn, key->u.aes_gmac.rx_pn, 6) <= 0) {
 		key->u.aes_gmac.replays++;
-		return RX_DROP_UNUSABLE;
+		return RX_DROP_U_REPLAY;
 	}
 
 	if (!(status->flag & RX_FLAG_DECRYPTED)) {
@@ -1104,7 +1104,7 @@  ieee80211_crypto_aes_gmac_decrypt(struct ieee80211_rx_data *rx)
 		    crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 			key->u.aes_gmac.icverrors++;
 			kfree(mic);
-			return RX_DROP_UNUSABLE;
+			return RX_DROP_U_MIC_FAIL;
 		}
 		kfree(mic);
 	}