ieee80211: Print human-readable disassoc/deauth reason codes

Create a function to return a descriptive string for each reason code,
and print that in addition to the numeric value in the kernel log. These
codes are easily found on popular search engines, but one is generally
not able to access the internet when dealing with wireless connectivity
issues.
Signed-off-by: Calvin Owens <jcalvinowens@gmail.com>
[use 'unknown' rather than 'invalid' since more valid codes exist]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -2249,6 +2249,62 @@ static void ieee80211_rx_mgmt_auth(struct ieee80211_sub_if_data *sdata,
 	/* ignore frame -- wait for timeout */
 }
 
+#define case_WLAN(type) \
+	case WLAN_REASON_##type: return #type
+
+static const char *ieee80211_get_reason_code_string(u16 reason_code)
+{
+	switch (reason_code) {
+	case_WLAN(UNSPECIFIED);
+	case_WLAN(PREV_AUTH_NOT_VALID);
+	case_WLAN(DEAUTH_LEAVING);
+	case_WLAN(DISASSOC_DUE_TO_INACTIVITY);
+	case_WLAN(DISASSOC_AP_BUSY);
+	case_WLAN(CLASS2_FRAME_FROM_NONAUTH_STA);
+	case_WLAN(CLASS3_FRAME_FROM_NONASSOC_STA);
+	case_WLAN(DISASSOC_STA_HAS_LEFT);
+	case_WLAN(STA_REQ_ASSOC_WITHOUT_AUTH);
+	case_WLAN(DISASSOC_BAD_POWER);
+	case_WLAN(DISASSOC_BAD_SUPP_CHAN);
+	case_WLAN(INVALID_IE);
+	case_WLAN(MIC_FAILURE);
+	case_WLAN(4WAY_HANDSHAKE_TIMEOUT);
+	case_WLAN(GROUP_KEY_HANDSHAKE_TIMEOUT);
+	case_WLAN(IE_DIFFERENT);
+	case_WLAN(INVALID_GROUP_CIPHER);
+	case_WLAN(INVALID_PAIRWISE_CIPHER);
+	case_WLAN(INVALID_AKMP);
+	case_WLAN(UNSUPP_RSN_VERSION);
+	case_WLAN(INVALID_RSN_IE_CAP);
+	case_WLAN(IEEE8021X_FAILED);
+	case_WLAN(CIPHER_SUITE_REJECTED);
+	case_WLAN(DISASSOC_UNSPECIFIED_QOS);
+	case_WLAN(DISASSOC_QAP_NO_BANDWIDTH);
+	case_WLAN(DISASSOC_LOW_ACK);
+	case_WLAN(DISASSOC_QAP_EXCEED_TXOP);
+	case_WLAN(QSTA_LEAVE_QBSS);
+	case_WLAN(QSTA_NOT_USE);
+	case_WLAN(QSTA_REQUIRE_SETUP);
+	case_WLAN(QSTA_TIMEOUT);
+	case_WLAN(QSTA_CIPHER_NOT_SUPP);
+	case_WLAN(MESH_PEER_CANCELED);
+	case_WLAN(MESH_MAX_PEERS);
+	case_WLAN(MESH_CONFIG);
+	case_WLAN(MESH_CLOSE);
+	case_WLAN(MESH_MAX_RETRIES);
+	case_WLAN(MESH_CONFIRM_TIMEOUT);
+	case_WLAN(MESH_INVALID_GTK);
+	case_WLAN(MESH_INCONSISTENT_PARAM);
+	case_WLAN(MESH_INVALID_SECURITY);
+	case_WLAN(MESH_PATH_ERROR);
+	case_WLAN(MESH_PATH_NOFORWARD);
+	case_WLAN(MESH_PATH_DEST_UNREACHABLE);
+	case_WLAN(MAC_EXISTS_IN_MBSS);
+	case_WLAN(MESH_CHAN_REGULATORY);
+	case_WLAN(MESH_CHAN);
+	default: return "<unknown>";
+	}
+}
 
 static void ieee80211_rx_mgmt_deauth(struct ieee80211_sub_if_data *sdata,
 				     struct ieee80211_mgmt *mgmt, size_t len)
@@ -2270,8 +2326,8 @@ static void ieee80211_rx_mgmt_deauth(struct ieee80211_sub_if_data *sdata,
 
 	reason_code = le16_to_cpu(mgmt->u.deauth.reason_code);
 
-	sdata_info(sdata, "deauthenticated from %pM (Reason: %u)\n",
-		   bssid, reason_code);
+	sdata_info(sdata, "deauthenticated from %pM (Reason: %u=%s)\n",
+		   bssid, reason_code, ieee80211_get_reason_code_string(reason_code));
 
 	ieee80211_set_disassoc(sdata, 0, 0, false, NULL);
 
@@ -4340,8 +4396,8 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
 	bool report_frame = false;
 
 	sdata_info(sdata,
-		   "deauthenticating from %pM by local choice (reason=%d)\n",
-		   req->bssid, req->reason_code);
+		   "deauthenticating from %pM by local choice (Reason: %u=%s)\n",
+		   req->bssid, req->reason_code, ieee80211_get_reason_code_string(req->reason_code));
 
 	if (ifmgd->auth_data) {
 		drv_mgd_prepare_tx(sdata->local, sdata);
@@ -4387,8 +4443,8 @@ int ieee80211_mgd_disassoc(struct ieee80211_sub_if_data *sdata,
 		return -ENOLINK;
 
 	sdata_info(sdata,
-		   "disassociating from %pM by local choice (reason=%d)\n",
-		   req->bss->bssid, req->reason_code);
+		   "disassociating from %pM by local choice (Reason: %u=%s)\n",
+		   req->bss->bssid, req->reason_code, ieee80211_get_reason_code_string(req->reason_code));
 
 	memcpy(bssid, req->bss->bssid, ETH_ALEN);
 	ieee80211_set_disassoc(sdata, IEEE80211_STYPE_DISASSOC,