chore(appup): update appup.src

fix(frame): server_keepalive only for MQTT v5.0

.gitignore

@@ -42,3 +42,11 @@ erlang.mk
 etc/emqx.conf.rendered
 Mnesia.*/
 .stamp
+erlang_ls.config
+# Emacs Backup files
+*~
+# Emacs temporary files
+.#*
+*#
+# For direnv
+.envrc

etc/emqx.conf

@@ -202,9 +202,11 @@ mqtt.max_packet_size = 1MB
 mqtt.max_clientid_len = 65535
 
 ## Maximum topic levels allowed. 0 means no limit.
+## Depth so big may lead to subscribing performance issues.
 ##
-## Value: Number
+## Value: Number [0-65535]
-mqtt.max_topic_levels = 0
+## Default: 128
+mqtt.max_topic_levels = 128
 
 ## Maximum QoS allowed.
 ##
@@ -242,7 +244,7 @@ mqtt.ignore_loop_deliver = false
 mqtt.strict_mode = false
 
 ## Specify the response information returned to the client
-## 
+##
 ## Value: String
 ## mqtt.response_information = example
 
@@ -296,6 +298,16 @@ broker.shared_dispatch_ack_enabled = false
 ## Value: Flag
 broker.route_batch_clean = off
 
+## Performance toggle for subscribe/unsubscribe wildcard topic.
+## Change this toggle only when there are many wildcard topics.
+## Value: Enum
+##  - key:   mnesia translational updates with per-key locks. recommended for single node setup.
+##  - tab:   mnesia translational updates with table lock. recommended for multi-nodes setup.
+##  - global: global lock protected updates. recommended for larger cluster.
+## NOTE: when changing from/to 'global' lock, it requires all nodes in the cluster
+## to be stopped before the change.
+broker.perf.route_lock_type = key
+
 ##-------------------------------------------------------------------
 ## Plugins
 ##-------------------------------------------------------------------

etc/listeners.conf

@@ -544,6 +544,16 @@ listener.ws.external.verify_protocol_header = on
 ## Value: Duration
 ## listener.ws.external.proxy_protocol_timeout = 3s
 
+## See: listener.ssl.$name.peer_cert_as_username
+##
+## Value: cn
+## listener.ws.external.peer_cert_as_username = cn
+
+## See: listener.ssl.$name.peer_cert_as_clientid
+##
+## Value: cn
+## listener.ws.external.peer_cert_as_clientid = cn
+
 ## The TCP backlog of external MQTT/WebSocket Listener.
 ##
 ## See: listener.ws.$name.backlog

etc/logger.conf

@@ -10,7 +10,7 @@
 ## - file: write logs only to file
 ## - console: write logs only to standard I/O
 ## - both: write logs both to file and standard I/O
-log.to = both
+log.to = file
 
 ## The log severity level.
 ##
@@ -167,4 +167,4 @@ log.rotation.count = 5
 ## Value: MaxBurstCount,TimeWindow
 ## Default: disabled
 ##
-#log.burst_limit = 20000, 1s
+#log.burst_limit = 20000, 1s

etc/zones.conf

@@ -57,8 +57,9 @@ zone.external.force_shutdown_policy = 10000|32MB
 ## zone.external.max_clientid_len = 1024
 
 ## Maximum topic levels allowed. 0 means no limit.
+## Depth so big may lead to subscribing performance issues.
 ##
-## Value: Number
+## Value: Number [0-65535]
 ## zone.external.max_topic_levels = 7
 
 ## Maximum QoS allowed.
@@ -184,6 +185,30 @@ zone.external.enable_flapping_detect = off
 ## Example: 100KB incoming per 10 seconds.
 #zone.external.rate_limit.conn_bytes_in = 100KB,10s
 
+## Whether to alarm the congested connections.
+##
+## Sometimes the mqtt connection (usually an MQTT subscriber) may get "congested" because
+## there're too many packets to sent. The socket trys to buffer the packets until the buffer is
+## full. If more packets comes after that, the packets will be "pending" in a queue
+## and we consider the connection is "congested".
+##
+## Enable this to send an alarm when there's any bytes pending in the queue. You could set
+## the `listener.tcp.<ZoneName>.sndbuf` to a larger value if the alarm is triggered too often.
+##
+## The name of the alarm is of format "conn_congestion/<ClientID>/<Username>".
+## Where the <ClientID> is the client-id of the congested MQTT connection.
+## And the <Username> is the username or "unknown_user" of not provided by the client.
+## Default: off
+#zone.external.conn_congestion.alarm = off
+
+## Won't clear the congested alarm in how long time.
+## The alarm is cleared only when there're no pending bytes in the queue, and also it has been
+## `min_alarm_sustain_duration` time since the last time we considered the connection is "congested".
+##
+## This is to avoid clearing and sending the alarm again too often.
+## Default: 1m
+#zone.external.conn_congestion.min_alarm_sustain_duration = 1m
+
 ## Messages quota for the each of external MQTT connection.
 ## This value consumed by the number of recipient on a message.
 ##
@@ -226,7 +251,7 @@ zone.external.ignore_loop_deliver = false
 zone.external.strict_mode = false
 
 ## Specify the response information returned to the client
-## 
+##
 ## Value: String
 ## zone.external.response_information = example
 
@@ -317,7 +342,7 @@ zone.internal.ignore_loop_deliver = false
 zone.internal.strict_mode = false
 
 ## Specify the response information returned to the client
-## 
+##
 ## Value: String
 ## zone.internal.response_information = example
 

include/emqx_mqtt.hrl

@@ -30,11 +30,13 @@
 %% MQTT Protocol Version and Names
 %%--------------------------------------------------------------------
 
+-define(MQTT_SN_PROTO_V1, 1).
 -define(MQTT_PROTO_V3, 3).
 -define(MQTT_PROTO_V4, 4).
 -define(MQTT_PROTO_V5, 5).
 
 -define(PROTOCOL_NAMES, [
+    {?MQTT_SN_PROTO_V1, <<"MQTT-SN">>}, %% XXX:Compatible with emqx-sn plug-in
     {?MQTT_PROTO_V3, <<"MQIsdp">>},
     {?MQTT_PROTO_V4, <<"MQTT">>},
     {?MQTT_PROTO_V5, <<"MQTT">>}]).

priv/emqx.schema

@@ -757,7 +757,7 @@ end}.
 
 %% @doc Set the Maximum topic levels.
 {mapping, "mqtt.max_topic_levels", "emqx.max_topic_levels", [
-  {default, 0},
+  {default, 128},
   {datatype, integer}
 ]}.
 
@@ -999,6 +999,16 @@ end}.
   {datatype, string}
 ]}.
 
+{mapping, "zone.$name.conn_congestion.alarm", "emqx.zones", [
+  {datatype, flag},
+  {default, off}
+]}.
+
+{mapping, "zone.$name.conn_congestion.min_alarm_sustain_duration", "emqx.zones", [
+  {default, "1m"},
+  {datatype, {duration, ms}}
+]}.
+
 {mapping, "zone.$name.quota.conn_messages_routing", "emqx.zones", [
   {datatype, string}
 ]}.
@@ -1128,6 +1138,10 @@ end}.
                    {ratelimit, {conn_messages_in, Ratelimit(Val)}};
                (["rate_limit", "conn_bytes_in"], Val) ->
                    {ratelimit, {conn_bytes_in, Ratelimit(Val)}};
+               (["conn_congestion", "alarm"], Val) ->
+                   {conn_congestion_alarm_enabled, Val};
+               (["conn_congestion", "min_alarm_sustain_duration"], Val) ->
+                   {conn_congestion_min_alarm_sustain_duration, Val};
                (["quota", "conn_messages_routing"], Val) ->
                    {quota, {conn_messages_routing, Ratelimit(Val)}};
                (["quota", "overall_messages_routing"], Val) ->
@@ -1573,7 +1587,11 @@ end}.
 ]}.
 
 {mapping, "listener.ws.$name.peer_cert_as_username", "emqx.listeners", [
-  {datatype, {enum, [cn, dn, crt]}}
+  {datatype, {enum, [cn]}}
+]}.
+
+{mapping, "listener.ws.$name.peer_cert_as_clientid", "emqx.listeners", [
+  {datatype, {enum, [cn]}}
 ]}.
 
 %%--------------------------------------------------------------------
@@ -2008,6 +2026,18 @@ end}.
   {datatype, flag}
 ]}.
 
+%% @doc Performance toggle for subscribe/unsubscribe wildcard topic.
+%%      Change this toggle only when there are many wildcard topics.
+%% key:   mnesia translational updates with per-key locks. recommended for single node setup.
+%% tab:   mnesia translational updates with table lock. recommended for multi-nodes setup.
+%% global: global lock protected updates. recommended for larger cluster.
+%% NOTE: when changing from/to 'global' lock, it requires all nodes in the cluster
+%%
+{mapping, "broker.perf.route_lock_type", "emqx.route_lock_type", [
+  {default, key},
+  {datatype, {enum, [key, tab, global]}}
+]}.
+
 %%--------------------------------------------------------------------
 %% System Monitor
 %%--------------------------------------------------------------------

rebar.config

@@ -6,8 +6,8 @@
  [{gproc, {git, "https://github.com/uwiger/gproc", {tag, "0.8.0"}}},
   {jiffy, {git, "https://github.com/emqx/jiffy", {tag, "1.0.5"}}},
   {cowboy, {git, "https://github.com/emqx/cowboy", {tag, "2.7.1"}}},
-  {esockd, {git, "https://github.com/emqx/esockd", {tag, "5.7.5"}}},
+  {esockd, {git, "https://github.com/emqx/esockd", {tag, "5.7.6"}}},
-  {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.7.5"}}},
+  {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.7.10"}}},
   {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "2.5.0"}}},
   {cuttlefish, {git, "https://github.com/emqx/cuttlefish", {tag, "v3.0.0"}}}
  ]}.

src/emqx.appup.src

@@ -1,4 +1,4 @@
-%% -*-: erlang -*-
+%% -*- mode: erlang -*-
 
 {VSN,
  [
@@ -6,6 +6,7 @@
      {add_module, emqx_congestion},
      {load_module, emqx_alarm, brutal_purge, soft_purge, []},
      {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
      {load_module, emqx_metrics, brutal_purge, soft_purge, []},
      {load_module, emqx_limiter, brutal_purge, soft_purge, []},
      {suspend, [esockd_acceptor,emqx_connection, emqx_ws_connection]},
@@ -14,12 +15,24 @@
      {update, emqx_ws_connection, {advanced, []}},
      {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
      {load_module, emqx_shared_sub, brutal_purge, soft_purge, []},
-     {resume, [esockd_acceptor,emqx_connection, emqx_ws_connection]}
+     {resume, [esockd_acceptor,emqx_connection, emqx_ws_connection]},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, []},
+     {load_module, emqx_router, soft_purge, soft_purge, [emqx_trie]},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]}
    ]},
    {"4.2.1", [
      {add_module, emqx_congestion},
      {load_module, emqx_alarm, brutal_purge, soft_purge, []},
      {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
      {load_module, emqx_limiter, brutal_purge, soft_purge, []},
      {suspend, [esockd_acceptor, emqx_connection, emqx_ws_connection]},
      {load_module, emqx_frame, brutal_purge, soft_purge, []},
@@ -27,15 +40,129 @@
      {update, emqx_ws_connection, {advanced, []}},
      {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
      {load_module, emqx_shared_sub, brutal_purge, soft_purge, []},
-     {resume, [esockd_acceptor, emqx_connection, emqx_ws_connection]}
+     {resume, [esockd_acceptor, emqx_connection, emqx_ws_connection]},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, []},
+     {load_module, emqx_router, soft_purge, soft_purge, [emqx_trie]},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]}
    ]},
    {<<"4.2.[23]">>, [
      {add_module, emqx_congestion},
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
      {load_module, emqx_alarm, brutal_purge, soft_purge, []},
      {load_module, emqx_channel, brutal_purge, soft_purge, []},
-     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
+     {update, emqx_connection, {advanced, []}},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
      {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
-     {load_module, emqx_shared_sub, brutal_purge, soft_purge, []}
+     {load_module, emqx_shared_sub, brutal_purge, soft_purge, []},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, []},
+     {load_module, emqx_router, soft_purge, soft_purge, [emqx_trie]},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.4">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
+     {load_module, emqx_congestion, brutal_purge, soft_purge, []},
+     {update, emqx_connection, {advanced, []}},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, []},
+     {load_module, emqx_router, soft_purge, soft_purge, [emqx_trie]},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.5">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
+     {load_module, emqx_congestion, brutal_purge, soft_purge, []},
+     {update, emqx_connection, {advanced, []}},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, []},
+     {load_module, emqx_router, soft_purge, soft_purge, [emqx_trie]},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.[6-7]">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.8">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.9">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.10">>, [
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []}
    ]},
    {<<".*">>, []}
  ],
@@ -51,8 +178,20 @@
      {update, emqx_connection, {advanced, []}},
      {update, emqx_ws_connection, {advanced, []}},
      {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
      {resume, [esockd_acceptor, emqx_connection, emqx_ws_connection]},
-     {delete_module, emqx_congestion}
+     {delete_module, emqx_congestion},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, [emqx_router]},
+     {load_module, emqx_router, soft_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]}
    ]},
    {"4.2.1", [
      {load_module, emqx_shared_sub, brutal_purge, soft_purge, []},
@@ -60,20 +199,135 @@
      {load_module, emqx_limiter, brutal_purge, soft_purge, []},
      {suspend, [esockd_acceptor, emqx_connection, emqx_ws_connection]},
      {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
      {load_module, emqx_frame, brutal_purge, soft_purge, []},
      {update, emqx_connection, {advanced, []}},
      {update, emqx_ws_connection, {advanced, []}},
      {load_module, emqx_alarm, brutal_purge, soft_purge, []},
      {resume, [esockd_acceptor, emqx_connection, emqx_ws_connection]},
-     {delete_module, emqx_congestion}
+     {delete_module, emqx_congestion},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, [emqx_router]},
+     {load_module, emqx_router, soft_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]}
    ]},
    {<<"4.2.[23]">>, [
      {load_module, emqx_shared_sub, brutal_purge, soft_purge, []},
      {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
-     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {update, emqx_connection, {advanced, []}},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
      {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
      {load_module, emqx_alarm, brutal_purge, soft_purge, []},
-     {delete_module, emqx_congestion}
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {delete_module, emqx_congestion},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, [emqx_router]},
+     {load_module, emqx_router, soft_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.4">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_congestion, brutal_purge, soft_purge, []},
+     {update, emqx_connection, {advanced, []}},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, [emqx_router]},
+     {load_module, emqx_router, soft_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.5">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_session, brutal_purge, soft_purge, []},
+     {load_module, emqx_congestion, brutal_purge, soft_purge, []},
+     {update, emqx_connection, {advanced, []}},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_router_sup, soft_purge, soft_purge, []},
+     {load_module, emqx_broker, soft_purge, soft_purge, []},
+     {load_module, emqx_trie, soft_purge, soft_purge, [emqx_router]},
+     {load_module, emqx_router, soft_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.[6-7]">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_access_rule, brutal_purge, soft_purge, []},
+     {load_module, emqx_pqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_mqueue,brutal_purge,soft_purge,[]},
+     {load_module, emqx_alarm_handler,brutal_purge,soft_purge,[]},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_misc,brutal_purge,soft_purge,[]},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.8">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_cm, brutal_purge, soft_purge, []},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.9">>, [
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_ws_connection, brutal_purge, soft_purge, []},
+     {load_module, emqx_limiter, brutal_purge, soft_purge, []},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []}
+   ]},
+   {<<"4.2.10">>, [
+     {load_module, emqx_channel, brutal_purge, soft_purge, []},
+     {load_module, emqx_frame, brutal_purge, soft_purge, []},
+     {load_module, emqx_app, brutal_purge, soft_purge, []},
+     {load_module, emqx_os_mon, brutal_purge, soft_purge, []},
+     {load_module, emqx_alarm, brutal_purge, soft_purge, []}
    ]},
    {<<".*">>, []}
  ]

src/emqx_access_rule.erl

@@ -28,7 +28,8 @@
 -type(who() :: all | binary() |
                {client, binary()} |
                {user, binary()} |
-               {ipaddr, esockd_cidr:cidr_string()}).
+               {ipaddr, esockd_cidr:cidr_string()} |
+               {ipaddrs, list(esockd_cidr:cidr_string())}).
 
 -type(access() :: subscribe | publish | pubsub).
 
@@ -52,6 +53,8 @@ compile(who, all) ->
     all;
 compile(who, {ipaddr, CIDR}) ->
     {ipaddr, esockd_cidr:parse(CIDR, true)};
+compile(who, {ipaddrs, CIDRs}) ->
+    {ipaddrs, lists:map(fun(CIDR) -> esockd_cidr:parse(CIDR, true) end, CIDRs)};
 compile(who, {client, all}) ->
     {client, all};
 compile(who, {client, ClientId}) ->
@@ -108,8 +111,14 @@ match_who(#{username := Username}, {user, Username}) ->
     true;
 match_who(#{peerhost := undefined}, {ipaddr, _Tup}) ->
     false;
+match_who(#{peerhost := undefined}, {ipaddrs, _}) ->
+    false;
 match_who(#{peerhost := IP}, {ipaddr, CIDR}) ->
     esockd_cidr:match(IP, CIDR);
+match_who(#{peerhost := IP}, {ipaddrs, CIDRs}) ->
+    lists:any(fun(CIDR) ->
+        esockd_cidr:match(IP, CIDR)
+    end, CIDRs);
 match_who(ClientInfo, {'and', Conds}) when is_list(Conds) ->
     lists:foldl(fun(Who, Allow) ->
                   match_who(ClientInfo, Who) andalso Allow

src/emqx_alarm.erl

@@ -56,9 +56,9 @@
           name :: binary() | atom(),
 
           details :: map() | list(),
-    
+
           message :: binary(),
-    
+
           activate_at :: integer()
         }).
 
@@ -68,9 +68,9 @@
           name :: binary() | atom(),
 
           details :: map() | list(),
-    
+
           message :: binary(),
-    
+
           deactivate_at :: integer() | infinity
         }).
 
@@ -165,6 +165,8 @@ init([Opts]) ->
     Actions = proplists:get_value(actions, Opts),
     SizeLimit = proplists:get_value(size_limit, Opts),
     ValidityPeriod = timer:seconds(proplists:get_value(validity_period, Opts)),
+    emqx_alarm_handler:load(),
+    process_flag(trap_exit, true),
     {ok, ensure_delete_timer(#state{actions = Actions,
                                     size_limit = SizeLimit,
                                     validity_period = ValidityPeriod})}.
@@ -228,6 +230,7 @@ handle_info(Info, State) ->
     {noreply, State}.
 
 terminate(_Reason, _State) ->
+    emqx_alarm_handler:unload(),
     ok.
 
 code_change(_OldVsn, State, _Extra) ->
@@ -361,7 +364,7 @@ normalize_message(partition, #{occurred := Node}) ->
     list_to_binary(io_lib:format("Partition occurs at node ~s", [Node]));
 normalize_message(<<"resource", _/binary>>, #{type := Type, id := ID}) ->
     list_to_binary(io_lib:format("Resource ~s(~s) is down", [Type, ID]));
-normalize_message(<<"mqtt_conn/congested/", Info/binary>>, _) ->
+normalize_message(<<"conn_congestion/", Info/binary>>, _) ->
-    list_to_binary(io_lib:format("MQTT connection congested: ~s", [Info]));
+    list_to_binary(io_lib:format("connection congested: ~s", [Info]));
 normalize_message(_Name, _UnknownDetails) ->
     <<"Unknown alarm">>.

src/emqx_alarm_handler.erl

@@ -56,20 +56,20 @@ init({_Args, {alarm_handler, _ExistingAlarms}}) ->
 init(_) ->
     {ok, []}.
 
-handle_event({set_alarm, {system_memory_high_watermark, []}}, State) -> 
+handle_event({set_alarm, {system_memory_high_watermark, []}}, State) ->
     emqx_alarm:activate(high_system_memory_usage, #{high_watermark => emqx_os_mon:get_sysmem_high_watermark()}),
     {ok, State};
 
-handle_event({set_alarm, {process_memory_high_watermark, Pid}}, State) -> 
+handle_event({set_alarm, {process_memory_high_watermark, Pid}}, State) ->
-    emqx_alarm:activate(high_process_memory_usage, #{pid => Pid,
+    emqx_alarm:activate(high_process_memory_usage, #{pid => list_to_binary(pid_to_list(Pid)),
                                                      high_watermark => emqx_os_mon:get_procmem_high_watermark()}),
     {ok, State};
 
-handle_event({clear_alarm, system_memory_high_watermark}, State) -> 
+handle_event({clear_alarm, system_memory_high_watermark}, State) ->
     emqx_alarm:deactivate(high_system_memory_usage),
     {ok, State};
 
-handle_event({clear_alarm, process_memory_high_watermark}, State) -> 
+handle_event({clear_alarm, process_memory_high_watermark}, State) ->
     emqx_alarm:deactivate(high_process_memory_usage),
     {ok, State};
 
@@ -85,4 +85,4 @@ handle_call(_Query, State) ->
 terminate(swap, _State) ->
     {emqx_alarm_handler, []};
 terminate(_, _) ->
-    ok.
+    ok.

src/emqx_app.erl

@@ -38,13 +38,11 @@ start(_Type, _Args) ->
     ok = emqx_plugins:init(),
     emqx_plugins:load(),
     register(emqx, self()),
-    emqx_alarm_handler:load(),
     print_vsn(),
     {ok, Sup}.
 
 -spec(stop(State :: term()) -> term()).
 stop(_State) ->
-    emqx_alarm_handler:unload(),
     emqx_boot:is_enabled(listeners)
       andalso emqx_listeners:stop().
 
@@ -68,4 +66,3 @@ start_autocluster() ->
     ekka:callback(prepare, fun emqx:shutdown/1),
     ekka:callback(reboot,  fun emqx:reboot/0),
     ekka:autocluster(?APP).
-

src/emqx_broker.erl

@@ -419,7 +419,7 @@ safe_update_stats(Tab, Stat, MaxStat) ->
 -compile({inline, [call/2, cast/2, pick/1]}).
 
 call(Broker, Req) ->
-    gen_server:call(Broker, Req).
+    gen_server:call(Broker, Req, infinity).
 
 cast(Broker, Msg) ->
     gen_server:cast(Broker, Msg).

src/emqx_channel.erl

@@ -32,6 +32,8 @@
 -export([ info/1
         , info/2
         , set_conn_state/2
+        , get_session/1
+        , set_session/2
         , stats/1
         , caps/1
         ]).
@@ -46,6 +48,12 @@
         , terminate/2
         ]).
 
+%% Export for emqx_sn
+-export([ do_deliver/2
+        , ensure_keepalive/2
+        , clear_keepalive/1
+        ]).
+
 %% Exports for CT
 -export([set_field/3]).
 
@@ -167,6 +175,12 @@ info(timers, #channel{timers = Timers}) -> Timers.
 set_conn_state(ConnState, Channel) ->
     Channel#channel{conn_state = ConnState}.
 
+get_session(#channel{session = Session}) ->
+    Session.
+
+set_session(Session, Channel) ->
+    Channel#channel{session = Session}.
+
 %% TODO: Add more stats.
 -spec(stats(channel()) -> emqx_types:stats()).
 stats(#channel{session = Session})->
@@ -931,8 +945,11 @@ handle_info({sock_closed, Reason}, Channel =
         Shutdown -> Shutdown
     end;
 
-handle_info({sock_closed, Reason}, Channel = #channel{conn_state = disconnected}) ->
+handle_info({sock_closed, _Reason}, Channel = #channel{conn_state = disconnected}) ->
-    ?LOG(error, "Unexpected sock_closed: ~p", [Reason]),
+    %% Since sock_closed messages can be generated multiple times,
+    %% we can simply ignore errors of this type in the disconnected state.
+    %% e.g. when the socket send function returns an error, there is already
+    %% a tcp_closed delivered to the process mailbox
     {ok, Channel};
 
 handle_info(clean_acl_cache, Channel) ->
@@ -1438,11 +1455,13 @@ enrich_connack_caps(AckProps, _Channel) -> AckProps.
 %%--------------------------------------------------------------------
 %% Enrich server keepalive
 
-enrich_server_keepalive(AckProps, #channel{clientinfo = #{zone := Zone}}) ->
+enrich_server_keepalive(AckProps, ?IS_MQTT_V5 = #channel{clientinfo = #{zone := Zone}}) ->
     case emqx_zone:server_keepalive(Zone) of
         undefined -> AckProps;
         Keepalive -> AckProps#{'Server-Keep-Alive' => Keepalive}
-    end.
+    end;
+
+enrich_server_keepalive(AckProps, _Channel) -> AckProps.
 
 %%--------------------------------------------------------------------
 %% Enrich response information
@@ -1488,7 +1507,7 @@ init_alias_maximum(#mqtt_packet_connect{proto_ver  = ?MQTT_PROTO_V5,
 init_alias_maximum(_ConnPkt, _ClientInfo) -> undefined.
 
 %%--------------------------------------------------------------------
-%% Enrich Keepalive
+%% Ensure Keepalive
 
 ensure_keepalive(#{'Server-Keep-Alive' := Interval}, Channel) ->
     ensure_keepalive_timer(Interval, Channel);
@@ -1501,6 +1520,15 @@ ensure_keepalive_timer(Interval, Channel = #channel{clientinfo = #{zone := Zone}
     Keepalive = emqx_keepalive:init(round(timer:seconds(Interval) * Backoff)),
     ensure_timer(alive_timer, Channel#channel{keepalive = Keepalive}).
 
+clear_keepalive(Channel = #channel{timers = Timers}) ->
+    case maps:get(alive_timer, Timers, undefined) of
+        undefined ->
+            Channel;
+        TRef ->
+            emqx_misc:cancel_timer(TRef),
+            Channel#channel{timers = maps:without([alive_timer], Timers)}
+    end.
+
 %%--------------------------------------------------------------------
 %% Maybe Resume Session
 
@@ -1645,4 +1673,3 @@ flag(false) -> 0.
 set_field(Name, Value, Channel) ->
     Pos = emqx_misc:index_of(Name, record_info(fields, channel)),
     setelement(Pos+1, Channel, Value).
-

src/emqx_cm.erl

@@ -70,7 +70,10 @@
         ]).
 
 %% Internal export
--export([stats_fun/0]).
+-export([stats_fun/0, clean_down/1]).
+
+%% Test export
+-export([register_channel_/3]).
 
 -type(chan_pid() :: pid()).
 
@@ -91,6 +94,10 @@
 %% Server name
 -define(CM, ?MODULE).
 
+-define(T_KICK, 5000).
+-define(T_GET_INFO, 5000).
+-define(T_TAKEOVER, 15000).
+
 %% @doc Start the channel manager.
 -spec(start_link() -> startlink_ret()).
 start_link() ->
@@ -159,7 +166,7 @@ get_chan_info(ClientId, ChanPid) when node(ChanPid) == node() ->
         error:badarg -> undefined
     end;
 get_chan_info(ClientId, ChanPid) ->
-    rpc_call(node(ChanPid), get_chan_info, [ClientId, ChanPid]).
+    rpc_call(node(ChanPid), get_chan_info, [ClientId, ChanPid], ?T_GET_INFO).
 
 %% @doc Update infos of the channel.
 -spec(set_chan_info(emqx_types:clientid(), emqx_types:attrs()) -> boolean()).
@@ -184,7 +191,7 @@ get_chan_stats(ClientId, ChanPid) when node(ChanPid) == node() ->
         error:badarg -> undefined
     end;
 get_chan_stats(ClientId, ChanPid) ->
-    rpc_call(node(ChanPid), get_chan_stats, [ClientId, ChanPid]).
+    rpc_call(node(ChanPid), get_chan_stats, [ClientId, ChanPid], ?T_GET_INFO).
 
 %% @doc Set channel's stats.
 -spec(set_chan_stats(emqx_types:clientid(), emqx_types:stats()) -> boolean()).
@@ -222,7 +229,7 @@ open_session(false, ClientInfo = #{clientid := ClientId}, ConnInfo) ->
                       case takeover_session(ClientId) of
                           {ok, ConnMod, ChanPid, Session} ->
                               ok = emqx_session:resume(ClientInfo, Session),
-                              Pendings = ConnMod:call(ChanPid, {takeover, 'end'}),
+                              Pendings = ConnMod:call(ChanPid, {takeover, 'end'}, ?T_TAKEOVER),
                               register_channel_(ClientId, Self, ConnInfo),
                               {ok, #{session  => Session,
                                      present  => true,
@@ -252,7 +259,7 @@ takeover_session(ClientId) ->
             takeover_session(ClientId, ChanPid);
         ChanPids ->
             [ChanPid|StalePids] = lists:reverse(ChanPids),
-            ?LOG(error, "More than one channel found: ~p", [ChanPids]),
+            ?LOG(error, "more_than_one_channel_found: ~p", [ChanPids]),
             lists:foreach(fun(StalePid) ->
                                   catch discard_session(ClientId, StalePid)
                           end, StalePids),
@@ -264,67 +271,111 @@ takeover_session(ClientId, ChanPid) when node(ChanPid) == node() ->
         undefined ->
             {error, not_found};
         ConnMod when is_atom(ConnMod) ->
-            Session = ConnMod:call(ChanPid, {takeover, 'begin'}),
+            %% TODO: if takeover times out, maybe kill the old?
+            Session = ConnMod:call(ChanPid, {takeover, 'begin'}, ?T_TAKEOVER),
             {ok, ConnMod, ChanPid, Session}
     end;
-
 takeover_session(ClientId, ChanPid) ->
-    rpc_call(node(ChanPid), takeover_session, [ClientId, ChanPid]).
+    rpc_call(node(ChanPid), takeover_session, [ClientId, ChanPid], ?T_TAKEOVER).
 
 %% @doc Discard all the sessions identified by the ClientId.
 -spec(discard_session(emqx_types:clientid()) -> ok).
 discard_session(ClientId) when is_binary(ClientId) ->
     case lookup_channels(ClientId) of
         [] -> ok;
-        ChanPids ->
+        ChanPids -> lists:foreach(fun(Pid) -> discard_session(ClientId, Pid) end, ChanPids)
-            lists:foreach(
-              fun(ChanPid) ->
-                      try
-                          discard_session(ClientId, ChanPid)
-                      catch
-                          _:{noproc,_}:_Stk -> ok;
-                          _:{{shutdown,_},_}:_Stk -> ok;
-                          _:Error:_Stk ->
-                              ?LOG(error, "Failed to discard ~0p: ~0p", [ChanPid, Error])
-                      end
-              end, ChanPids)
     end.
 
-discard_session(ClientId, ChanPid) when node(ChanPid) == node() ->
+%% @private Kick a local stale session to force it step down.
-    case get_chann_conn_mod(ClientId, ChanPid) of
+%% If failed to kick (e.g. timeout) force a kill.
-        undefined -> ok;
+%% Keeping the stale pid around, or returning error or raise an exception
-        ConnMod when is_atom(ConnMod) ->
+%% benefits nobody.
-            ConnMod:call(ChanPid, discard)
+-spec kick_or_kill(kick | discard, module(), pid()) -> ok.
-    end;
+kick_or_kill(Action, ConnMod, Pid) ->
+    try
+        %% this is essentailly a gen_server:call implemented in emqx_connection
+        %% and emqx_ws_connection.
+        %% the handle_call is implemented in emqx_channel
+        ok = apply(ConnMod, call, [Pid, Action, ?T_KICK])
+    catch
+        _ : noproc -> % emqx_ws_connection: call
+            ?LOG(debug, "session_already_gone: ~p, action: ~p", [Pid, Action]),
+            ok;
+        _ : {noproc, _} -> % emqx_connection: gen_server:call
+            ?LOG(debug, "session_already_gone: ~p, action: ~p", [Pid, Action]),
+            ok;
+        _ : {shutdown, _} ->
+            ?LOG(debug, "session_already_shutdown: ~p, action: ~p", [Pid, Action]),
+            ok;
+        _ : {{shutdown, _}, _} ->
+            ?LOG(debug, "session_already_shutdown: ~p, action: ~p", [Pid, Action]),
+            ok;
+        _ : {timeout, {gen_server, call, _}} ->
+            ?LOG(warning, "session_kick_timeout: ~p, action: ~p, "
+                          "stale_channel: ~p",
+                          [Pid, Action, stale_channel_info(Pid)]),
+            ok = force_kill(Pid);
+        _ : Error ->
+            ?LOG(error, "session_kick_exception: ~p, action: ~p, "
+                        "reason: ~p, stacktrace: ~p, stale_channel: ~p",
+                        [Pid, Action, Error, erlang:get_stacktrace(), stale_channel_info(Pid)]),
+            ok = force_kill(Pid)
+    end.
+
+force_kill(Pid) ->
+    exit(Pid, kill),
+    ok.
+
+stale_channel_info(Pid) ->
+    process_info(Pid, [status, message_queue_len, current_stacktrace]).
 
 discard_session(ClientId, ChanPid) ->
-    rpc_call(node(ChanPid), discard_session, [ClientId, ChanPid]).
+    kick_session(discard, ClientId, ChanPid).
+
+kick_session(ClientId, ChanPid) ->
+    kick_session(kick, ClientId, ChanPid).
+
+%% @private This function is shared for session 'kick' and 'discard' (as the first arg Action).
+kick_session(Action, ClientId, ChanPid) when node(ChanPid) == node() ->
+    case get_chann_conn_mod(ClientId, ChanPid) of
+        undefined ->
+            %% already deregistered
+            ok;
+        ConnMod when is_atom(ConnMod) ->
+            ok = kick_or_kill(Action, ConnMod, ChanPid)
+    end;
+kick_session(Action, ClientId, ChanPid) ->
+    %% call remote node on the old APIs because we do not know if they have upgraded
+    %% to have kick_session/3
+    Function = case Action of
+                   discard -> discard_session;
+                   kick -> kick_session
+               end,
+    try
+        rpc_call(node(ChanPid), Function, [ClientId, ChanPid], ?T_KICK)
+    catch
+        Error : Reason ->
+            %% This should mostly be RPC failures.
+            %% However, if the node is still running the old version
+            %% code (prior to emqx app 4.3.10) some of the RPC handler
+            %% exceptions may get propagated to a new version node
+            ?LOG(error, "failed_to_kick_session_on_remote_node ~p: ~p ~p ~p",
+                 [node(ChanPid), Action, Error, Reason])
+    end.
 
 kick_session(ClientId) ->
     case lookup_channels(ClientId) of
-        [] -> {error, not_found};
+        [] ->
-        [ChanPid] ->
+            ?LOG(warning, "kiecked_an_unknown_session ~ts", [ClientId]),
-            kick_session(ClientId, ChanPid);
+            ok;
         ChanPids ->
-            [ChanPid|StalePids] = lists:reverse(ChanPids),
+            case length(ChanPids) > 1 of
-            ?LOG(error, "More than one channel found: ~p", [ChanPids]),
+                true -> ?LOG(info, "more_than_one_channel_found: ~p", [ChanPids]);
-            lists:foreach(fun(StalePid) ->
+                false -> ok
-                                  catch discard_session(ClientId, StalePid)
+            end,
-                          end, StalePids),
+            lists:foreach(fun(Pid) -> kick_session(ClientId, Pid) end, ChanPids)
-            kick_session(ClientId, ChanPid)
     end.
 
-kick_session(ClientId, ChanPid) when node(ChanPid) == node() ->
-    case get_chan_info(ClientId, ChanPid) of
-        #{conninfo := #{conn_mod := ConnMod}} ->
-            ConnMod:call(ChanPid, kick);
-        undefined ->
-            {error, not_found}
-    end;
-
-kick_session(ClientId, ChanPid) ->
-    rpc_call(node(ChanPid), kick_session, [ClientId, ChanPid]).
-
 %% @doc Is clean start?
 % is_clean_start(#{clean_start := false}) -> false;
 % is_clean_start(_Attrs) -> true.
@@ -360,10 +411,16 @@ lookup_channels(local, ClientId) ->
     [ChanPid || {_, ChanPid} <- ets:lookup(?CHAN_TAB, ClientId)].
 
 %% @private
-rpc_call(Node, Fun, Args) ->
+rpc_call(Node, Fun, Args, Timeout) ->
-    case rpc:call(Node, ?MODULE, Fun, Args) of
+    case rpc:call(Node, ?MODULE, Fun, Args, 2 * Timeout) of
-        {badrpc, Reason} -> error(Reason);
+        {badrpc, Reason} ->
-        Res -> Res
+            %% since eqmx app 4.3.10, the 'kick' and 'discard' calls hanndler
+            %% should catch all exceptions and always return 'ok'.
+            %% This leaves 'badrpc' only possible when there is problem
+            %% calling the remote node.
+            error({badrpc, Reason});
+        Res ->
+            Res
     end.
 
 %% @private
@@ -396,7 +453,7 @@ handle_cast(Msg, State) ->
 handle_info({'DOWN', _MRef, process, Pid, _Reason}, State = #{chan_pmon := PMon}) ->
     ChanPids = [Pid | emqx_misc:drain_down(?BATCH_SIZE)],
     {Items, PMon1} = emqx_pmon:erase_all(ChanPids, PMon),
-    ok = emqx_pool:async_submit(fun lists:foreach/2, [fun clean_down/1, Items]),
+    ok = emqx_pool:async_submit(fun lists:foreach/2, [fun ?MODULE:clean_down/1, Items]),
     {noreply, State#{chan_pmon := PMon1}};
 
 handle_info(Info, State) ->
@@ -432,5 +489,5 @@ get_chann_conn_mod(ClientId, ChanPid) when node(ChanPid) == node() ->
         error:badarg -> undefined
     end;
 get_chann_conn_mod(ClientId, ChanPid) ->
-    rpc_call(node(ChanPid), get_chann_conn_mod, [ClientId, ChanPid]).
+    rpc_call(node(ChanPid), get_chann_conn_mod, [ClientId, ChanPid], ?T_GET_INFO).
 

src/emqx_congestion.erl

@@ -16,17 +16,16 @@
 
 -module(emqx_congestion).
 
--export([ maybe_alarm_port_busy/3
+-export([ maybe_alarm_conn_congestion/3
-        , maybe_alarm_port_busy/4
-        , maybe_alarm_too_many_publish/5
-        , maybe_alarm_too_many_publish/6
         , cancel_alarms/3
         ]).
 
 -define(ALARM_CONN_CONGEST(Channel, Reason),
-        list_to_binary(io_lib:format("mqtt_conn/congested/~s/~s/~s", [emqx_channel:info(clientid, Channel),
+        list_to_binary(
-         maps:get(username, emqx_channel:info(clientinfo, Channel), <<"undefined">>),
+          io_lib:format("~s/~s/~s",
-         Reason]))).
+                        [Reason, emqx_channel:info(clientid, Channel),
+                         maps:get(username, emqx_channel:info(clientinfo, Channel),
+                                  <<"unknown_user">>)]))).
 
 -define(ALARM_CONN_INFO_KEYS, [
     socktype, sockname, peername, clientid, username, proto_name, proto_ver,
@@ -36,44 +35,28 @@
 -define(ALARM_SOCK_OPTS_KEYS, [high_watermark, high_msgq_watermark, sndbuf, recbuf, buffer]).
 -define(PROC_INFO_KEYS, [message_queue_len, memory, reductions]).
 -define(ALARM_SENT(REASON), {alarm_sent, REASON}).
--define(ALL_ALARM_REASONS, [port_busy, too_many_publish]).
+-define(ALL_ALARM_REASONS, [conn_congestion]).
--define(CONFIRM_CLEAR(REASON), {alarm_confirm_clear, REASON}).
+-define(WONT_CLEAR_IN, 60000).
--define(CONFIRM_CLEAR_INTERVAL, 10000).
 
-maybe_alarm_port_busy(Socket, Transport, Channel) ->
+maybe_alarm_conn_congestion(Socket, Transport, Channel) ->
-    maybe_alarm_port_busy(Socket, Transport, Channel, false).
+    case is_alarm_enabled(Channel) of
-
+        false -> ok;
-maybe_alarm_port_busy(Socket, Transport, Channel, ForceClear) ->
+        true ->
-    case is_tcp_congested(Socket, Transport) of
+            case is_tcp_congested(Socket, Transport) of
-        true -> alarm_congestion(Socket, Transport, Channel, port_busy);
+                true -> alarm_congestion(Socket, Transport, Channel, conn_congestion);
-        false -> cancel_alarm_congestion(Socket, Transport, Channel, port_busy,
+                false -> cancel_alarm_congestion(Socket, Transport, Channel, conn_congestion)
-                    ForceClear)
+            end
     end.
 
-maybe_alarm_too_many_publish(Socket, Transport, Channel, PubMsgCount,
-        MaxBatchSize) ->
-    maybe_alarm_too_many_publish(Socket, Transport, Channel, PubMsgCount,
-        MaxBatchSize, false).
-
-maybe_alarm_too_many_publish(Socket, Transport, Channel, PubMsgCount,
-        PubMsgCount = _MaxBatchSize, _ForceClear) ->
-    %% we only alarm it when the process is "too busy"
-    alarm_congestion(Socket, Transport, Channel, too_many_publish);
-maybe_alarm_too_many_publish(Socket, Transport, Channel, PubMsgCount,
-        _MaxBatchSize, ForceClear) when PubMsgCount == 0 ->
-    %% but we clear the alarm until it is really "idle", to avoid sending
-    %% alarms and clears too frequently
-    cancel_alarm_congestion(Socket, Transport, Channel, too_many_publish,
-        ForceClear);
-maybe_alarm_too_many_publish(_Socket, _Transport, _Channel, _PubMsgCount,
-        _MaxBatchSize, _ForceClear) ->
-    ok.
-
 cancel_alarms(Socket, Transport, Channel) ->
     lists:foreach(fun(Reason) ->
         do_cancel_alarm_congestion(Socket, Transport, Channel, Reason)
     end, ?ALL_ALARM_REASONS).
 
+is_alarm_enabled(Channel) ->
+    emqx_zone:get_env(emqx_channel:info(zone, Channel),
+        conn_congestion_alarm_enabled, false).
+
 alarm_congestion(Socket, Transport, Channel, Reason) ->
     case has_alarm_sent(Reason) of
         false -> do_alarm_congestion(Socket, Transport, Channel, Reason);
@@ -82,8 +65,11 @@ alarm_congestion(Socket, Transport, Channel, Reason) ->
             update_alarm_sent_at(Reason)
     end.
 
-cancel_alarm_congestion(Socket, Transport, Channel, Reason, ForceClear) ->
+cancel_alarm_congestion(Socket, Transport, Channel, Reason) ->
-    case is_alarm_allowed_clear(Reason, ForceClear) of
+    Zone = emqx_channel:info(zone, Channel),
+    WontClearIn = emqx_zone:get_env(Zone, conn_congestion_min_alarm_sustain_duration,
+                    ?WONT_CLEAR_IN),
+    case has_alarm_sent(Reason) andalso long_time_since_last_alarm(Reason, WontClearIn) of
         true -> do_cancel_alarm_congestion(Socket, Transport, Channel, Reason);
         false -> ok
     end.
@@ -123,13 +109,11 @@ get_alarm_sent_at(Reason) ->
         LastSentAt -> LastSentAt
     end.
 
-is_alarm_allowed_clear(Reason, _ForceClear = true) ->
+long_time_since_last_alarm(Reason, WontClearIn) ->
-    has_alarm_sent(Reason);
-is_alarm_allowed_clear(Reason, _ForceClear = false) ->
     %% only sent clears when the alarm was not triggered in the last
-    %% ?CONFIRM_CLEAR_INTERVAL time
+    %% WontClearIn time
     case timenow() - get_alarm_sent_at(Reason) of
-        Elapse when Elapse >= ?CONFIRM_CLEAR_INTERVAL -> true;
+        Elapse when Elapse >= WontClearIn -> true;
         _ -> false
     end.
 

src/emqx_connection.erl

@@ -38,7 +38,7 @@
         , stats/1
         ]).
 
--export([call/2]).
+-export([call/2, call/3]).
 
 %% Callback
 -export([init/4]).
@@ -168,7 +168,9 @@ stats(#state{transport = Transport,
     lists:append([SockStats, ConnStats, ChanStats, ProcStats]).
 
 call(Pid, Req) ->
-    gen_server:call(Pid, Req, infinity).
+    call(Pid, Req, infinity).
+call(Pid, Req, Timeout) ->
+    gen_server:call(Pid, Req, Timeout).
 
 stop(Pid) ->
     gen_server:stop(Pid).
@@ -374,12 +376,8 @@ handle_msg({Passive, _Sock}, State)
     handle_info(activate_socket, NState1);
 
 handle_msg(Deliver = {deliver, _Topic, _Msg},
-           #state{active_n = MaxBatchSize, transport = Transport,
+           #state{active_n = ActiveN} = State) ->
-                  socket = Socket, channel = Channel} = State) ->
+    Delivers = [Deliver|emqx_misc:drain_deliver(ActiveN)],
-    Delivers0 = emqx_misc:drain_deliver(MaxBatchSize),
-    emqx_congestion:maybe_alarm_too_many_publish(Socket, Transport, Channel,
-        length(Delivers0), MaxBatchSize),
-    Delivers = [Deliver|Delivers0],
     with_channel(handle_deliver, [Delivers], State);
 
 %% Something sent
@@ -548,12 +546,9 @@ handle_timeout(_TRef, limit_timeout, State) ->
                         },
     handle_info(activate_socket, NState);
 
-handle_timeout(_TRef, emit_stats, State = #state{active_n = MaxBatchSize,
+handle_timeout(_TRef, emit_stats, State = #state{channel = Channel, transport = Transport,
-        channel = Channel, transport = Transport, socket = Socket}) ->
+        socket = Socket}) ->
-    {_, MsgQLen} = erlang:process_info(self(), message_queue_len),
+    emqx_congestion:maybe_alarm_conn_congestion(Socket, Transport, Channel),
-    emqx_congestion:maybe_alarm_port_busy(Socket, Transport, Channel, true),
-    emqx_congestion:maybe_alarm_too_many_publish(Socket, Transport, Channel,
-        MsgQLen, MaxBatchSize, true),
     ClientId = emqx_channel:info(clientid, Channel),
     emqx_cm:set_chan_stats(ClientId, stats(State)),
     {ok, State#state{stats_timer = undefined}};
@@ -594,6 +589,11 @@ parse_incoming(Data, Packets, State = #state{parse_state = ParseState}) ->
             NState = State#state{parse_state = NParseState},
             parse_incoming(Rest, [Packet|Packets], NState)
     catch
+        error:proxy_protocol_config_disabled ->
+            ?LOG(error,
+                 "~nMalformed packet, "
+                 "please check proxy_protocol config for specific listeners and zones~n"),
+            {[{frame_error, proxy_protocol_config_disabled} | Packets], State};
         error:Reason:Stk ->
             ?LOG(error, "~nParse failed for ~0p~n~0p~nFrame data:~0p",
                  [Reason, Stk, Data]),
@@ -666,7 +666,7 @@ send(IoData, #state{transport = Transport, socket = Socket, channel = Channel})
     Oct = iolist_size(IoData),
     ok = emqx_metrics:inc('bytes.sent', Oct),
     emqx_pd:inc_counter(outgoing_bytes, Oct),
-    emqx_congestion:maybe_alarm_port_busy(Socket, Transport, Channel),
+    emqx_congestion:maybe_alarm_conn_congestion(Socket, Transport, Channel),
     case Transport:async_send(Socket, IoData, [nosuspend]) of
         ok -> ok;
         Error = {error, _Reason} ->
@@ -690,7 +690,10 @@ handle_info(activate_socket, State = #state{sockstate = OldSst}) ->
     end;
 
 handle_info({sock_error, Reason}, State) ->
-    Reason =/= closed andalso ?LOG(error, "Socket error: ~p", [Reason]),
+    case Reason =/= closed andalso Reason =/= einval of
+        true -> ?LOG(warning, "socket_error: ~p", [Reason]);
+        false -> ok
+    end,
     handle_info({sock_closed, Reason}, close_socket(State));
 
 handle_info(Info, State) ->
@@ -814,4 +817,3 @@ stop(Reason, Reply, State) ->
 set_field(Name, Value, State) ->
     Pos = emqx_misc:index_of(Name, record_info(fields, state)),
     setelement(Pos+1, State, Value).
-

src/emqx_frame.erl

@@ -67,8 +67,21 @@
           version     => ?MQTT_PROTO_V4
          }).
 
+-define(MULTIPLIER_MAX, 16#200000).
+
+%% proxy_protocol v1 header human readable
+-define(PPV1_PROXY, "PROXY ").
+-define(PPV1_PROXY_UNKNOWN, "PROXY UNKNOWN").
+%% proxy_protocol v2 header signature:
+%% 16#0D,16#0A, 16#0D,16#0A,16#00,16#0D,16#0A,16#51,16#55,16#49,16#54,16#0A
+-define(PPV2_HEADER_SIG, "\r\n\r\n\0\r\nQUIT\n").
+
 -dialyzer({no_match, [serialize_utf8_string/2]}).
 
+-ifdef(TEST).
+-export([parse_variable_byte_integer/1]).
+-endif.
+
 %%--------------------------------------------------------------------
 %% Init Parse State
 %%--------------------------------------------------------------------
@@ -96,6 +109,13 @@ parse(Bin) ->
 -spec(parse(binary(), parse_state()) -> parse_result()).
 parse(<<>>, {none, Options}) ->
     {more, {none, Options}};
+parse(<<?PPV1_PROXY, IPVer:5/binary, _Rest/binary>>, {none, _Options})
+  when IPVer =:= <<"TCP4 ">> orelse IPVer =:= <<"TCP6 ">> ->
+    error(proxy_protocol_config_disabled);
+parse(<<?PPV1_PROXY_UNKNOWN, _Rest/binary>>, {none, _Options}) ->
+    error(proxy_protocol_config_disabled);
+parse(<<?PPV2_HEADER_SIG, _Rest/binary>>, {none, _Options}) ->
+    error(proxy_protocol_config_disabled);
 parse(<<Type:4, Dup:1, QoS:2, Retain:1, Rest/binary>>,
       {none, Options = #{strict_mode := StrictMode}}) ->
     %% Validate header if strict mode.
@@ -141,6 +161,9 @@ parse_remaining_len(<<0:8, Rest/binary>>, Header, 1, 0, Options) ->
 %% Match PUBACK, PUBREC, PUBREL, PUBCOMP, UNSUBACK...
 parse_remaining_len(<<0:1, 2:7, Rest/binary>>, Header, 1, 0, Options) ->
     parse_frame(Rest, Header, 2, Options);
+parse_remaining_len(<<1:1, _Len:7, _Rest/binary>>, _Header, Multiplier, _Value, _Options)
+  when Multiplier > ?MULTIPLIER_MAX ->
+    error(malformed_variable_byte_integer);
 parse_remaining_len(<<1:1, Len:7, Rest/binary>>, Header, Multiplier, Value, Options) ->
     parse_remaining_len(Rest, Header, Multiplier * ?HIGHBIT, Value + Len * Multiplier, Options);
 parse_remaining_len(<<0:1, Len:7, Rest/binary>>, Header, Multiplier, Value,
@@ -177,8 +200,9 @@ packet(Header, Variable) ->
 packet(Header, Variable, Payload) ->
     #mqtt_packet{header = Header, variable = Variable, payload = Payload}.
 
-parse_packet(#mqtt_packet_header{type = ?CONNECT}, FrameBin, _Options) ->
+parse_packet(#mqtt_packet_header{type = ?CONNECT}, FrameBin,
-    {ProtoName, Rest} = parse_utf8_string(FrameBin),
+             #{strict_mode := StrictMode}) ->
+    {ProtoName, Rest} = parse_utf8_string(FrameBin, StrictMode),
     <<BridgeTag:4, ProtoVer:4, Rest1/binary>> = Rest,
     % Note: Crash when reserved flag doesn't equal to 0, there is no strict
     % compliance with the MQTT5.0.
@@ -192,8 +216,8 @@ parse_packet(#mqtt_packet_header{type = ?CONNECT}, FrameBin, _Options) ->
       KeepAlive    : 16/big,
       Rest2/binary>> = Rest1,
 
-    {Properties, Rest3} = parse_properties(Rest2, ProtoVer),
+    {Properties, Rest3} = parse_properties(Rest2, ProtoVer, StrictMode),
-    {ClientId, Rest4} = parse_utf8_string(Rest3),
+    {ClientId, Rest4} = parse_utf8_string(Rest3, StrictMode),
     ConnPacket = #mqtt_packet_connect{proto_name  = ProtoName,
                                       proto_ver   = ProtoVer,
                                       is_bridge   = (BridgeTag =:= 8),
@@ -205,14 +229,14 @@ parse_packet(#mqtt_packet_header{type = ?CONNECT}, FrameBin, _Options) ->
                                       properties  = Properties,
                                       clientid    = ClientId
                                      },
-    {ConnPacket1, Rest5} = parse_will_message(ConnPacket, Rest4),
+    {ConnPacket1, Rest5} = parse_will_message(ConnPacket, Rest4, StrictMode),
-    {Username, Rest6} = parse_utf8_string(Rest5, bool(UsernameFlag)),
+    {Username, Rest6} = parse_utf8_string(Rest5, StrictMode, bool(UsernameFlag)),
-    {Passsword, <<>>} = parse_utf8_string(Rest6, bool(PasswordFlag)),
+    {Passsword, <<>>} = parse_utf8_string(Rest6, StrictMode, bool(PasswordFlag)),
     ConnPacket1#mqtt_packet_connect{username = Username, password = Passsword};
 
-parse_packet(#mqtt_packet_header{type = ?CONNACK},
+parse_packet(#mqtt_packet_header{type = ?CONNACK}, <<AckFlags:8, ReasonCode:8, Rest/binary>>,
-             <<AckFlags:8, ReasonCode:8, Rest/binary>>, #{version := Ver}) ->
+             #{strict_mode := StrictMode, version := Ver}) ->
-    {Properties, <<>>} = parse_properties(Rest, Ver),
+    {Properties, <<>>} = parse_properties(Rest, Ver, StrictMode),
     #mqtt_packet_connack{ack_flags   = AckFlags,
                          reason_code = ReasonCode,
                          properties  = Properties
@@ -220,21 +244,22 @@ parse_packet(#mqtt_packet_header{type = ?CONNACK},
 
 parse_packet(#mqtt_packet_header{type = ?PUBLISH, qos = QoS}, Bin,
              #{strict_mode := StrictMode, version := Ver}) ->
-    {TopicName, Rest} = parse_utf8_string(Bin),
+    {TopicName, Rest} = parse_utf8_string(Bin, StrictMode),
     {PacketId, Rest1} = case QoS of
                             ?QOS_0 -> {undefined, Rest};
                             _ -> parse_packet_id(Rest)
                         end,
     (PacketId =/= undefined) andalso
       StrictMode andalso validate_packet_id(PacketId),
-    {Properties, Payload} = parse_properties(Rest1, Ver),
+    {Properties, Payload} = parse_properties(Rest1, Ver, StrictMode),
     Publish = #mqtt_packet_publish{topic_name = TopicName,
                                    packet_id  = PacketId,
                                    properties = Properties
                                   },
     {Publish, Payload};
 
-parse_packet(#mqtt_packet_header{type = PubAck}, <<PacketId:16/big>>, #{strict_mode := StrictMode})
+parse_packet(#mqtt_packet_header{type = PubAck}, <<PacketId:16/big>>,
+             #{strict_mode := StrictMode})
   when ?PUBACK =< PubAck, PubAck =< ?PUBCOMP ->
     StrictMode andalso validate_packet_id(PacketId),
     #mqtt_packet_puback{packet_id = PacketId, reason_code = 0};
@@ -243,7 +268,7 @@ parse_packet(#mqtt_packet_header{type = PubAck}, <<PacketId:16/big, ReasonCode,
              #{strict_mode := StrictMode, version := Ver = ?MQTT_PROTO_V5})
   when ?PUBACK =< PubAck, PubAck =< ?PUBCOMP ->
     StrictMode andalso validate_packet_id(PacketId),
-    {Properties, <<>>} = parse_properties(Rest, Ver),
+    {Properties, <<>>} = parse_properties(Rest, Ver, StrictMode),
     #mqtt_packet_puback{packet_id   = PacketId,
                         reason_code = ReasonCode,
                         properties  = Properties
@@ -252,7 +277,7 @@ parse_packet(#mqtt_packet_header{type = PubAck}, <<PacketId:16/big, ReasonCode,
 parse_packet(#mqtt_packet_header{type = ?SUBSCRIBE}, <<PacketId:16/big, Rest/binary>>,
              #{strict_mode := StrictMode, version := Ver}) ->
     StrictMode andalso validate_packet_id(PacketId),
-    {Properties, Rest1} = parse_properties(Rest, Ver),
+    {Properties, Rest1} = parse_properties(Rest, Ver, StrictMode),
     TopicFilters = parse_topic_filters(subscribe, Rest1),
     ok = validate_subqos([QoS || {_, #{qos := QoS}} <- TopicFilters]),
     #mqtt_packet_subscribe{packet_id     = PacketId,
@@ -263,7 +288,7 @@ parse_packet(#mqtt_packet_header{type = ?SUBSCRIBE}, <<PacketId:16/big, Rest/bin
 parse_packet(#mqtt_packet_header{type = ?SUBACK}, <<PacketId:16/big, Rest/binary>>,
              #{strict_mode := StrictMode, version := Ver}) ->
     StrictMode andalso validate_packet_id(PacketId),
-    {Properties, Rest1} = parse_properties(Rest, Ver),
+    {Properties, Rest1} = parse_properties(Rest, Ver, StrictMode),
     ReasonCodes = parse_reason_codes(Rest1),
     #mqtt_packet_suback{packet_id    = PacketId,
                         properties   = Properties,
@@ -273,7 +298,7 @@ parse_packet(#mqtt_packet_header{type = ?SUBACK}, <<PacketId:16/big, Rest/binary
 parse_packet(#mqtt_packet_header{type = ?UNSUBSCRIBE}, <<PacketId:16/big, Rest/binary>>,
              #{strict_mode := StrictMode, version := Ver}) ->
     StrictMode andalso validate_packet_id(PacketId),
-    {Properties, Rest1} = parse_properties(Rest, Ver),
+    {Properties, Rest1} = parse_properties(Rest, Ver, StrictMode),
     TopicFilters = parse_topic_filters(unsubscribe, Rest1),
     #mqtt_packet_unsubscribe{packet_id     = PacketId,
                              properties    = Properties,
@@ -288,7 +313,7 @@ parse_packet(#mqtt_packet_header{type = ?UNSUBACK}, <<PacketId:16/big>>,
 parse_packet(#mqtt_packet_header{type = ?UNSUBACK}, <<PacketId:16/big, Rest/binary>>,
              #{strict_mode := StrictMode, version := Ver}) ->
     StrictMode andalso validate_packet_id(PacketId),
-    {Properties, Rest1} = parse_properties(Rest, Ver),
+    {Properties, Rest1} = parse_properties(Rest, Ver, StrictMode),
     ReasonCodes = parse_reason_codes(Rest1),
     #mqtt_packet_unsuback{packet_id    = PacketId,
                           properties   = Properties,
@@ -296,118 +321,125 @@ parse_packet(#mqtt_packet_header{type = ?UNSUBACK}, <<PacketId:16/big, Rest/bina
                          };
 
 parse_packet(#mqtt_packet_header{type = ?DISCONNECT}, <<ReasonCode, Rest/binary>>,
-             #{version := ?MQTT_PROTO_V5}) ->
+             #{strict_mode := StrictMode, version := ?MQTT_PROTO_V5}) ->
-    {Properties, <<>>} = parse_properties(Rest, ?MQTT_PROTO_V5),
+    {Properties, <<>>} = parse_properties(Rest, ?MQTT_PROTO_V5, StrictMode),
     #mqtt_packet_disconnect{reason_code = ReasonCode,
                             properties  = Properties
                            };
 
 parse_packet(#mqtt_packet_header{type = ?AUTH}, <<ReasonCode, Rest/binary>>,
-             #{version := ?MQTT_PROTO_V5}) ->
+             #{strict_mode := StrictMode, version := ?MQTT_PROTO_V5}) ->
-    {Properties, <<>>} = parse_properties(Rest, ?MQTT_PROTO_V5),
+    {Properties, <<>>} = parse_properties(Rest, ?MQTT_PROTO_V5, StrictMode),
     #mqtt_packet_auth{reason_code = ReasonCode, properties = Properties}.
 
 parse_will_message(Packet = #mqtt_packet_connect{will_flag = true,
-                                                 proto_ver = Ver}, Bin) ->
+                                                 proto_ver = Ver},
-    {Props, Rest} = parse_properties(Bin, Ver),
+                   Bin, StrictMode) ->
-    {Topic, Rest1} = parse_utf8_string(Rest),
+    {Props, Rest} = parse_properties(Bin, Ver, StrictMode),
+    {Topic, Rest1} = parse_utf8_string(Rest, StrictMode),
     {Payload, Rest2} = parse_binary_data(Rest1),
     {Packet#mqtt_packet_connect{will_props   = Props,
                                 will_topic   = Topic,
                                 will_payload = Payload
                                }, Rest2};
-parse_will_message(Packet, Bin) -> {Packet, Bin}.
+parse_will_message(Packet, Bin, _StrictMode) -> {Packet, Bin}.
 
 -compile({inline, [parse_packet_id/1]}).
 parse_packet_id(<<PacketId:16/big, Rest/binary>>) ->
     {PacketId, Rest}.
 
-parse_properties(Bin, Ver) when Ver =/= ?MQTT_PROTO_V5 ->
+parse_properties(Bin, Ver, _StrictMode) when Ver =/= ?MQTT_PROTO_V5 ->
     {#{}, Bin};
 %% TODO: version mess?
-parse_properties(<<>>, ?MQTT_PROTO_V5) ->
+parse_properties(<<>>, ?MQTT_PROTO_V5, _StrictMode) ->
     {#{}, <<>>};
-parse_properties(<<0, Rest/binary>>, ?MQTT_PROTO_V5) ->
+parse_properties(<<0, Rest/binary>>, ?MQTT_PROTO_V5, _StrictMode) ->
     {#{}, Rest};
-parse_properties(Bin, ?MQTT_PROTO_V5) ->
+parse_properties(Bin, ?MQTT_PROTO_V5, StrictMode) ->
     {Len, Rest} = parse_variable_byte_integer(Bin),
     <<PropsBin:Len/binary, Rest1/binary>> = Rest,
-    {parse_property(PropsBin, #{}), Rest1}.
+    {parse_property(PropsBin, #{}, StrictMode), Rest1}.
 
-parse_property(<<>>, Props) ->
+parse_property(<<>>, Props, _StrictMode) ->
     Props;
-parse_property(<<16#01, Val, Bin/binary>>, Props) ->
+parse_property(<<16#01, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Payload-Format-Indicator' => Val});
+    parse_property(Bin, Props#{'Payload-Format-Indicator' => Val}, StrictMode);
-parse_property(<<16#02, Val:32/big, Bin/binary>>, Props) ->
+parse_property(<<16#02, Val:32/big, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Message-Expiry-Interval' => Val});
+    parse_property(Bin, Props#{'Message-Expiry-Interval' => Val}, StrictMode);
-parse_property(<<16#03, Bin/binary>>, Props) ->
+parse_property(<<16#03, Bin/binary>>, Props, StrictMode) ->
-    {Val, Rest} = parse_utf8_string(Bin),
+    {Val, Rest} = parse_utf8_string(Bin, StrictMode),
-    parse_property(Rest, Props#{'Content-Type' => Val});
+    parse_property(Rest, Props#{'Content-Type' => Val}, StrictMode);
-parse_property(<<16#08, Bin/binary>>, Props) ->
+parse_property(<<16#08, Bin/binary>>, Props, StrictMode) ->
-    {Val, Rest} = parse_utf8_string(Bin),
+    {Val, Rest} = parse_utf8_string(Bin, StrictMode),
-    parse_property(Rest, Props#{'Response-Topic' => Val});
+    parse_property(Rest, Props#{'Response-Topic' => Val}, StrictMode);
-parse_property(<<16#09, Len:16/big, Val:Len/binary, Bin/binary>>, Props) ->
+parse_property(<<16#09, Len:16/big, Val:Len/binary, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Correlation-Data' => Val});
+    parse_property(Bin, Props#{'Correlation-Data' => Val}, StrictMode);
-parse_property(<<16#0B, Bin/binary>>, Props) ->
+parse_property(<<16#0B, Bin/binary>>, Props, StrictMode) ->
     {Val, Rest} = parse_variable_byte_integer(Bin),
-    parse_property(Rest, Props#{'Subscription-Identifier' => Val});
+    parse_property(Rest, Props#{'Subscription-Identifier' => Val}, StrictMode);
-parse_property(<<16#11, Val:32/big, Bin/binary>>, Props) ->
+parse_property(<<16#11, Val:32/big, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Session-Expiry-Interval' => Val});
+    parse_property(Bin, Props#{'Session-Expiry-Interval' => Val}, StrictMode);
-parse_property(<<16#12, Bin/binary>>, Props) ->
+parse_property(<<16#12, Bin/binary>>, Props, StrictMode) ->
-    {Val, Rest} = parse_utf8_string(Bin),
+    {Val, Rest} = parse_utf8_string(Bin, StrictMode),
-    parse_property(Rest, Props#{'Assigned-Client-Identifier' => Val});
+    parse_property(Rest, Props#{'Assigned-Client-Identifier' => Val}, StrictMode);
-parse_property(<<16#13, Val:16, Bin/binary>>, Props) ->
+parse_property(<<16#13, Val:16, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Server-Keep-Alive' => Val});
+    parse_property(Bin, Props#{'Server-Keep-Alive' => Val}, StrictMode);
-parse_property(<<16#15, Bin/binary>>, Props) ->
+parse_property(<<16#15, Bin/binary>>, Props, StrictMode) ->
-    {Val, Rest} = parse_utf8_string(Bin),
+    {Val, Rest} = parse_utf8_string(Bin, StrictMode),
-    parse_property(Rest, Props#{'Authentication-Method' => Val});
+    parse_property(Rest, Props#{'Authentication-Method' => Val}, StrictMode);
-parse_property(<<16#16, Len:16/big, Val:Len/binary, Bin/binary>>, Props) ->
+parse_property(<<16#16, Len:16/big, Val:Len/binary, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Authentication-Data' => Val});
+    parse_property(Bin, Props#{'Authentication-Data' => Val}, StrictMode);
-parse_property(<<16#17, Val, Bin/binary>>, Props) ->
+parse_property(<<16#17, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Request-Problem-Information' => Val});
+    parse_property(Bin, Props#{'Request-Problem-Information' => Val}, StrictMode);
-parse_property(<<16#18, Val:32, Bin/binary>>, Props) ->
+parse_property(<<16#18, Val:32, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Will-Delay-Interval' => Val});
+    parse_property(Bin, Props#{'Will-Delay-Interval' => Val}, StrictMode);
-parse_property(<<16#19, Val, Bin/binary>>, Props) ->
+parse_property(<<16#19, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Request-Response-Information' => Val});
+    parse_property(Bin, Props#{'Request-Response-Information' => Val}, StrictMode);
-parse_property(<<16#1A, Bin/binary>>, Props) ->
+parse_property(<<16#1A, Bin/binary>>, Props, StrictMode) ->
-    {Val, Rest} = parse_utf8_string(Bin),
+    {Val, Rest} = parse_utf8_string(Bin, StrictMode),
-    parse_property(Rest, Props#{'Response-Information' => Val});
+    parse_property(Rest, Props#{'Response-Information' => Val}, StrictMode);
-parse_property(<<16#1C, Bin/binary>>, Props) ->
+parse_property(<<16#1C, Bin/binary>>, Props, StrictMode) ->
-    {Val, Rest} = parse_utf8_string(Bin),
+    {Val, Rest} = parse_utf8_string(Bin, StrictMode),
-    parse_property(Rest, Props#{'Server-Reference' => Val});
+    parse_property(Rest, Props#{'Server-Reference' => Val}, StrictMode);
-parse_property(<<16#1F, Bin/binary>>, Props) ->
+parse_property(<<16#1F, Bin/binary>>, Props, StrictMode) ->
-    {Val, Rest} = parse_utf8_string(Bin),
+    {Val, Rest} = parse_utf8_string(Bin, StrictMode),
-    parse_property(Rest, Props#{'Reason-String' => Val});
+    parse_property(Rest, Props#{'Reason-String' => Val}, StrictMode);
-parse_property(<<16#21, Val:16/big, Bin/binary>>, Props) ->
+parse_property(<<16#21, Val:16/big, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Receive-Maximum' => Val});
+    parse_property(Bin, Props#{'Receive-Maximum' => Val}, StrictMode);
-parse_property(<<16#22, Val:16/big, Bin/binary>>, Props) ->
+parse_property(<<16#22, Val:16/big, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Topic-Alias-Maximum' => Val});
+    parse_property(Bin, Props#{'Topic-Alias-Maximum' => Val}, StrictMode);
-parse_property(<<16#23, Val:16/big, Bin/binary>>, Props) ->
+parse_property(<<16#23, Val:16/big, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Topic-Alias' => Val});
+    parse_property(Bin, Props#{'Topic-Alias' => Val}, StrictMode);
-parse_property(<<16#24, Val, Bin/binary>>, Props) ->
+parse_property(<<16#24, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Maximum-QoS' => Val});
+    parse_property(Bin, Props#{'Maximum-QoS' => Val}, StrictMode);
-parse_property(<<16#25, Val, Bin/binary>>, Props) ->
+parse_property(<<16#25, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Retain-Available' => Val});
+    parse_property(Bin, Props#{'Retain-Available' => Val}, StrictMode);
-parse_property(<<16#26, Bin/binary>>, Props) ->
+parse_property(<<16#26, Bin/binary>>, Props, StrictMode) ->
-    {Pair, Rest} = parse_utf8_pair(Bin),
+    {Pair, Rest} = parse_utf8_pair(Bin, StrictMode),
     case maps:find('User-Property', Props) of
         {ok, UserProps} ->
             UserProps1 = lists:append(UserProps, [Pair]),
-            parse_property(Rest, Props#{'User-Property' := UserProps1});
+            parse_property(Rest, Props#{'User-Property' := UserProps1}, StrictMode);
         error ->
-            parse_property(Rest, Props#{'User-Property' => [Pair]})
+            parse_property(Rest, Props#{'User-Property' => [Pair]}, StrictMode)
     end;
-parse_property(<<16#27, Val:32, Bin/binary>>, Props) ->
+parse_property(<<16#27, Val:32, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Maximum-Packet-Size' => Val});
+    parse_property(Bin, Props#{'Maximum-Packet-Size' => Val}, StrictMode);
-parse_property(<<16#28, Val, Bin/binary>>, Props) ->
+parse_property(<<16#28, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Wildcard-Subscription-Available' => Val});
+    parse_property(Bin, Props#{'Wildcard-Subscription-Available' => Val}, StrictMode);
-parse_property(<<16#29, Val, Bin/binary>>, Props) ->
+parse_property(<<16#29, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Subscription-Identifier-Available' => Val});
+    parse_property(Bin, Props#{'Subscription-Identifier-Available' => Val}, StrictMode);
-parse_property(<<16#2A, Val, Bin/binary>>, Props) ->
+parse_property(<<16#2A, Val, Bin/binary>>, Props, StrictMode) ->
-    parse_property(Bin, Props#{'Shared-Subscription-Available' => Val}).
+    parse_property(Bin, Props#{'Shared-Subscription-Available' => Val}, StrictMode);
+parse_property(<<Property:8, _Rest/binary>>, _Props, _StrictMode) ->
+    error(#{invalid_property_code => Property}).
+%% TODO: invalid property in specific packet.
 
 parse_variable_byte_integer(Bin) ->
     parse_variable_byte_integer(Bin, 1, 0).
+parse_variable_byte_integer(<<1:1, _Len:7, _Rest/binary>>, Multiplier, _Value)
+  when Multiplier > ?MULTIPLIER_MAX ->
+    error(malformed_variable_byte_integer);
 parse_variable_byte_integer(<<1:1, Len:7, Rest/binary>>, Multiplier, Value) ->
     parse_variable_byte_integer(Rest, Multiplier * ?HIGHBIT, Value + Len * Multiplier);
 parse_variable_byte_integer(<<0:1, Len:7, Rest/binary>>, Multiplier, Value) ->
@@ -423,20 +455,53 @@ parse_topic_filters(unsubscribe, Bin) ->
 parse_reason_codes(Bin) ->
     [Code || <<Code>> <= Bin].
 
-parse_utf8_pair(<<Len1:16/big, Key:Len1/binary,
+%%--------------------
-                  Len2:16/big, Val:Len2/binary, Rest/binary>>) ->
+%% parse utf8 pair
-    {{Key, Val}, Rest}.
+parse_utf8_pair( <<Len1:16/big, Key:Len1/binary,
+                   Len2:16/big, Val:Len2/binary, Rest/binary>>
+               , true) ->
+    {{validate_utf8(Key), validate_utf8(Val)}, Rest};
+parse_utf8_pair( <<Len1:16/big, Key:Len1/binary,
+                   Len2:16/big, Val:Len2/binary, Rest/binary>>
+               , false) ->
+    {{Key, Val}, Rest};
+parse_utf8_pair(<<LenK:16/big, Rest/binary>>, _StrictMode)
+  when LenK > byte_size(Rest) ->
+    error(user_property_not_enough_bytes);
+parse_utf8_pair(<<LenK:16/big, _Key:LenK/binary, %% key maybe malformed
+                  LenV:16/big, Rest/binary>>, _StrictMode)
+  when LenV > byte_size(Rest) ->
+    error(malformed_user_property_value);
+parse_utf8_pair(Bin, _StrictMode)
+  when 4 > byte_size(Bin) ->
+    error(user_property_not_enough_bytes).
 
-parse_utf8_string(Bin, false) ->
+%%--------------------
+%% parse utf8 string
+parse_utf8_string(Bin, _StrictMode, false) ->
     {undefined, Bin};
-parse_utf8_string(Bin, true) ->
+parse_utf8_string(Bin, StrictMode, true) ->
-    parse_utf8_string(Bin).
+    parse_utf8_string(Bin, StrictMode).
 
-parse_utf8_string(<<Len:16/big, Str:Len/binary, Rest/binary>>) ->
+parse_utf8_string(<<Len:16/big, Str:Len/binary, Rest/binary>>, true) ->
-    {Str, Rest}.
+    {validate_utf8(Str), Rest};
+parse_utf8_string(<<Len:16/big, Str:Len/binary, Rest/binary>>, false) ->
+    {Str, Rest};
+parse_utf8_string(<<Len:16/big, Rest/binary>>, _)
+  when Len > byte_size(Rest) ->
+    error(malformed_utf8_string);
+parse_utf8_string(Bin, _)
+  when 2 > byte_size(Bin) ->
+    error(malformed_utf8_string_length).
 
 parse_binary_data(<<Len:16/big, Data:Len/binary, Rest/binary>>) ->
-    {Data, Rest}.
+    {Data, Rest};
+parse_binary_data(<<Len:16/big, Rest/binary>>)
+  when Len > byte_size(Rest) ->
+    error(malformed_binary_data);
+parse_binary_data(Bin)
+  when 2 > byte_size(Bin) ->
+    error(malformed_binary_data_length).
 
 %%--------------------------------------------------------------------
 %% Serialize MQTT Packet
@@ -774,3 +839,52 @@ fixqos(?PUBREL, 0)      -> 1;
 fixqos(?SUBSCRIBE, 0)   -> 1;
 fixqos(?UNSUBSCRIBE, 0) -> 1;
 fixqos(_Type, QoS)      -> QoS.
+
+validate_utf8(Bin) ->
+    case unicode:characters_to_binary(Bin) of
+        {error, _, _} ->
+            error(utf8_string_invalid);
+        {incomplete, _, _} ->
+            error(utf8_string_invalid);
+        Bin when is_binary(Bin) ->
+            case validate_mqtt_utf8_char(Bin) of
+                true -> Bin;
+                false -> error(utf8_string_invalid)
+            end
+    end.
+
+%% Is the utf8 string respecting UTF-8 characters defined by MQTT Spec?
+%% i.e. contains invalid UTF-8 char or control char
+validate_mqtt_utf8_char(<<>>) ->
+    true;
+%% ==== 1-Byte UTF-8 invalid: [[U+0000 .. U+001F] && [U+007F]]
+validate_mqtt_utf8_char(<<B1, Bs/binary>>)
+  when B1 >= 16#20, B1 =< 16#7E ->
+    validate_mqtt_utf8_char(Bs);
+validate_mqtt_utf8_char(<<B1, _Bs/binary>>)
+  when B1 >=  16#00, B1 =< 16#1F;
+       B1 =:= 16#7F ->
+    %% [U+0000 .. U+001F] && [U+007F]
+    false;
+%% ==== 2-Bytes UTF-8 invalid: [U+0080 .. U+009F]
+validate_mqtt_utf8_char(<<B1, B2, Bs/binary>>)
+  when B1 =:= 16#C2;
+       B2 >=  16#A0, B2 =< 16#BF;
+       B1  >  16#C3, B1 =< 16#DE;
+       B2 >=  16#80, B2 =< 16#BF ->
+    validate_mqtt_utf8_char(Bs);
+validate_mqtt_utf8_char(<<16#C2, B2, _Bs/binary>>)
+  when B2 >= 16#80, B2 =< 16#9F ->
+    %% [U+0080 .. U+009F]
+    false;
+%% ==== 3-Bytes UTF-8 invalid: [U+D800 .. U+DFFF]
+validate_mqtt_utf8_char(<<B1, _B2, _B3, Bs/binary>>)
+  when B1 >= 16#E0, B1 =< 16#EE;
+       B1 =:= 16#EF ->
+    validate_mqtt_utf8_char(Bs);
+validate_mqtt_utf8_char(<<16#ED, _B2, _B3, _Bs/binary>>) ->
+    false;
+%% ==== 4-Bytes UTF-8
+validate_mqtt_utf8_char(<<B1, _B2, _B3, _B4, Bs/binary>>)
+  when B1 =:= 16#0F ->
+    validate_mqtt_utf8_char(Bs).

src/emqx_limiter.erl

@@ -23,6 +23,7 @@
         , init/4 %% XXX: Compatible with before 4.2 version
         , info/1
         , check/2
+        , update_overall_limiter/4
         ]).
 
 -record(limiter, {
@@ -152,3 +153,15 @@ is_message_limiter(conn_messages_in) -> true;
 is_message_limiter(conn_messages_routing) -> true;
 is_message_limiter(overall_messages_routing) -> true;
 is_message_limiter(_) -> false.
+
+update_overall_limiter(Zone, Name, Capacity, Interval) ->
+    case is_overall_limiter(Name) of
+        false -> false;
+        _ ->
+            try
+                esockd_limiter:update({Zone, Name}, Capacity, Interval),
+                true
+            catch _:_:_ ->
+                    false
+            end
+    end.

src/emqx_misc.erl

@@ -45,6 +45,8 @@
         , index_of/2
         ]).
 
+-define(OOM_FACTOR, 1.25).
+
 %% @doc Merge options
 -spec(merge_opts(Opts, Opts) -> Opts when Opts :: proplists:proplist()).
 merge_opts(Defaults, Options) ->
@@ -185,8 +187,8 @@ do_check_oom([{Val, Max, Reason}|Rest]) ->
 
 tune_heap_size(#{max_heap_size := MaxHeapSize}) ->
     %% If set to zero, the limit is disabled.
-    erlang:process_flag(max_heap_size, #{size => MaxHeapSize,
+    erlang:process_flag(max_heap_size, #{size => must_kill_heap_size(MaxHeapSize),
-                                         kill => false,
+                                         kill => true,
                                          error_logger => true
                                         });
 tune_heap_size(undefined) -> ok.
@@ -233,3 +235,19 @@ index_of(E, I, [E|_]) ->
 index_of(E, I, [_|L]) ->
     index_of(E, I+1, L).
 
+must_kill_heap_size(Size) ->
+    %% We set the max allowed heap size by `erlang:process_flag(max_heap_size, #{size => Size})`,
+    %% where the `Size` cannot be set to an integer lager than `(1 bsl 59) - 1` on a 64-bit system,
+    %% or `(1 bsl 27) - 1` on a 32-bit system.
+    MaxAllowedSize = case erlang:system_info(wordsize) of
+        8 -> % arch_64
+            (1 bsl 59) - 1;
+        4 -> % arch_32
+            (1 bsl 27) - 1
+    end,
+    %% We multiply the size with factor ?OOM_FACTOR, to give the
+    %% process a chance to suicide by `check_oom/1`
+    case ceil(Size * ?OOM_FACTOR) of
+        Size0 when Size0 >= MaxAllowedSize -> MaxAllowedSize;
+        Size0 -> Size0
+    end.

src/emqx_mqueue.erl

@@ -67,6 +67,9 @@
         , dropped/1
         ]).
 
+-export([ live_upgrade/1
+        ]).
+
 -export_type([mqueue/0, options/0]).
 
 -type(topic() :: emqx_topic:topic()).
@@ -91,6 +94,11 @@
 -define(MAX_LEN_INFINITY, 0).
 -define(INFO_KEYS, [store_qos0, max_len, len, dropped]).
 
+-record(shift_opts, {
+          multiplier :: non_neg_integer(),
+          base       :: integer()
+         }).
+
 -record(mqueue, {
           store_qos0 = false              :: boolean(),
           max_len    = ?MAX_LEN_INFINITY  :: count(),
@@ -98,11 +106,16 @@
           dropped    = 0                  :: count(),
           p_table    = ?NO_PRIORITY_TABLE :: p_table(),
           default_p  = ?LOWEST_PRIORITY   :: priority(),
-          q          = ?PQUEUE:new()      :: pq()
+          q          = ?PQUEUE:new()      :: pq(),
+          shift_opts                      :: #shift_opts{},
+          last_p                          :: non_neg_integer() | undefined,
+          counter                         :: non_neg_integer() | undefined
          }).
 
 -type(mqueue() :: #mqueue{}).
 
+-define(OLD(Q), Q = {mqueue, _, _, _, _, _, _, _}).
+
 -spec(init(options()) -> mqueue()).
 init(Opts = #{max_len := MaxLen0, store_qos0 := QoS_0}) ->
     MaxLen = case (is_integer(MaxLen0) andalso MaxLen0 > ?MAX_LEN_INFINITY) of
@@ -112,7 +125,8 @@ init(Opts = #{max_len := MaxLen0, store_qos0 := QoS_0}) ->
     #mqueue{max_len = MaxLen,
             store_qos0 = QoS_0,
             p_table = get_opt(priorities, Opts, ?NO_PRIORITY_TABLE),
-            default_p = get_priority_opt(Opts)
+            default_p = get_priority_opt(Opts),
+            shift_opts = get_shift_opt(Opts)
            }.
 
 -spec(info(mqueue()) -> emqx_types:infos()).
@@ -127,22 +141,30 @@ info(max_len, #mqueue{max_len = MaxLen}) ->
 info(len, #mqueue{len = Len}) ->
     Len;
 info(dropped, #mqueue{dropped = Dropped}) ->
-    Dropped.
+    Dropped;
+info(Info, ?OLD(MQ)) ->
+    info(Info, live_upgrade(MQ)).
 
-is_empty(#mqueue{len = Len}) -> Len =:= 0.
+is_empty(#mqueue{len = Len}) -> Len =:= 0;
+is_empty(?OLD(MQ)) -> is_empty(live_upgrade(MQ)).
 
-len(#mqueue{len = Len}) -> Len.
+len(#mqueue{len = Len}) -> Len;
+len(?OLD(MQ)) -> len(live_upgrade(MQ)).
 
-max_len(#mqueue{max_len = MaxLen}) -> MaxLen.
+max_len(#mqueue{max_len = MaxLen}) -> MaxLen;
+max_len(?OLD(MQ)) -> max_len(live_upgrade(MQ)).
 
 %% @doc Return number of dropped messages.
 -spec(dropped(mqueue()) -> count()).
-dropped(#mqueue{dropped = Dropped}) -> Dropped.
+dropped(#mqueue{dropped = Dropped}) -> Dropped;
+dropped(?OLD(MQ)) -> dropped(live_upgrade(MQ)).
 
 %% @doc Stats of the mqueue
 -spec(stats(mqueue()) -> [stat()]).
 stats(#mqueue{max_len = MaxLen, dropped = Dropped} = MQ) ->
-    [{len, len(MQ)}, {max_len, MaxLen}, {dropped, Dropped}].
+    [{len, len(MQ)}, {max_len, MaxLen}, {dropped, Dropped}];
+stats(?OLD(MQ)) ->
+    stats(live_upgrade(MQ)).
 
 %% @doc Enqueue a message.
 -spec(in(message(), mqueue()) -> {maybe(message()), mqueue()}).
@@ -165,15 +187,34 @@ in(Msg = #message{topic = Topic}, MQ = #mqueue{default_p = Dp,
             {DroppedMsg, MQ#mqueue{q = Q2, dropped = Dropped + 1}};
         false ->
             {_DroppedMsg = undefined, MQ#mqueue{len = Len + 1, q = ?PQUEUE:in(Msg, Priority, Q)}}
-    end.
+    end;
+in(Msg, ?OLD(MQ)) ->
+    in(Msg, live_upgrade(MQ)).
 
 -spec(out(mqueue()) -> {empty | {value, message()}, mqueue()}).
 out(MQ = #mqueue{len = 0, q = Q}) ->
     0 = ?PQUEUE:len(Q), %% assert, in this case, ?PQUEUE:len should be very cheap
     {empty, MQ};
-out(MQ = #mqueue{q = Q, len = Len}) ->
+out(MQ = #mqueue{q = Q, len = Len, last_p = undefined, shift_opts = ShiftOpts}) ->
+    {{value, Val, Prio}, Q1} = ?PQUEUE:out_p(Q), %% Shouldn't fail, since we've checked the length
+    MQ1 = MQ#mqueue{
+            q = Q1,
+            len = Len - 1,
+            last_p = Prio,
+            counter = init_counter(Prio, ShiftOpts)
+           },
+    {{value, Val}, MQ1};
+out(MQ = #mqueue{q = Q, counter = 0}) ->
+    MQ1 = MQ#mqueue{
+            q      = ?PQUEUE:shift(Q),
+            last_p = undefined
+           },
+    out(MQ1);
+out(MQ = #mqueue{q = Q, len = Len, counter = Cnt}) ->
     {R, Q1} = ?PQUEUE:out(Q),
-    {R, MQ#mqueue{q = Q1, len = Len - 1}}.
+    {R, MQ#mqueue{q = Q1, len = Len - 1, counter = Cnt - 1}};
+out(?OLD(MQ)) ->
+    out(live_upgrade(MQ)).
 
 get_opt(Key, Opts, Default) ->
     case maps:get(Key, Opts, Default) of
@@ -194,3 +235,46 @@ get_priority_opt(Opts) ->
 %% while the highest 'infinity' is a [{infinity, queue:queue()}]
 get_priority(_Topic, ?NO_PRIORITY_TABLE, _) -> ?LOWEST_PRIORITY;
 get_priority(Topic, PTab, Dp) -> maps:get(Topic, PTab, Dp).
+
+init_counter(?HIGHEST_PRIORITY, Opts) ->
+    Infinity = 1000000,
+    init_counter(Infinity, Opts);
+init_counter(Prio, #shift_opts{multiplier = Mult, base = Base}) ->
+    (Prio + Base) * Mult.
+
+get_shift_opt(Opts) ->
+    Mult = maps:get(shift_multiplier, Opts, 10),
+    Min = case Opts of
+              #{p_table := PTab} ->
+                  case maps:size(PTab) of
+                      0 -> 0;
+                      _ -> lists:min(maps:values(PTab))
+                  end;
+              _ ->
+                  ?LOWEST_PRIORITY
+          end,
+    Base = case Min < 0 of
+               true  -> -Min;
+               false -> 0
+           end,
+    #shift_opts{
+       multiplier = Mult,
+       base       = Base
+      }.
+
+live_upgrade({mqueue, StoreQos0, MaxLen, Len, Dropped, PTable, DefaultP, Q}) ->
+    ShiftOpts = case is_map(PTable) of
+                    true  -> get_shift_opt(#{p_table => PTable});
+                    false -> get_shift_opt(#{})
+                end,
+    #mqueue{ store_qos0 = StoreQos0
+           , max_len    = MaxLen
+           , dropped    = Dropped
+           , p_table    = PTable
+           , default_p  = DefaultP
+           , len        = Len
+           , q          = Q
+           , shift_opts = ShiftOpts
+           , last_p     = undefined
+           , counter    = undefined
+           }.

src/emqx_os_mon.erl

@@ -81,7 +81,7 @@ get_mem_check_interval() ->
 
 set_mem_check_interval(Seconds) when Seconds < 60 ->
     memsup:set_check_interval(1);
-set_mem_check_interval(Seconds) -> 
+set_mem_check_interval(Seconds) ->
     memsup:set_check_interval(Seconds div 60).
 
 get_sysmem_high_watermark() ->
@@ -105,8 +105,10 @@ call(Req) ->
 
 init([Opts]) ->
     set_mem_check_interval(proplists:get_value(mem_check_interval, Opts)),
-    set_sysmem_high_watermark(proplists:get_value(sysmem_high_watermark, Opts)),
+    HW = proplists:get_value(sysmem_high_watermark, Opts),
+    set_sysmem_high_watermark(HW),
     set_procmem_high_watermark(proplists:get_value(procmem_high_watermark, Opts)),
+    ensure_system_memory_alarm(HW),
     {ok, ensure_check_timer(#{cpu_high_watermark => proplists:get_value(cpu_high_watermark, Opts),
                               cpu_low_watermark => proplists:get_value(cpu_low_watermark, Opts),
                               cpu_check_interval => proplists:get_value(cpu_check_interval, Opts),
@@ -177,3 +179,20 @@ ensure_check_timer(State = #{cpu_check_interval := Interval}) ->
         "x86_64-pc-linux-musl" -> State;
         _ -> State#{timer := emqx_misc:start_timer(timer:seconds(Interval), check)}
     end.
+
+%% At startup, memsup starts first and checks for memory alarms,
+%% but emqx_alarm_handler is not yet used instead of alarm_handler,
+%% so alarm_handler is used directly for notification (normally emqx_alarm_handler should be used).
+%%The internal memsup will no longer trigger events that have been alerted,
+%% and there is no exported function to remove the alerted flag,
+%% so it can only be checked again at startup.
+ensure_system_memory_alarm(HW) ->
+    case erlang:whereis(memsup) of
+        undefined -> ok;
+        _Pid ->
+            {Allocated, Total, _Worst} = memsup:get_memory_data(),
+            case Total =/= 0 andalso Allocated/Total * 100 >= HW of
+                true -> emqx_alarm:activate(high_system_memory_usage, #{high_watermark => HW});
+                false -> ok
+            end
+    end.

src/emqx_pqueue.erl

@@ -55,6 +55,7 @@
         , filter/2
         , fold/3
         , highest/1
+        , shift/1
         ]).
 
 -export_type([q/0]).
@@ -170,6 +171,14 @@ out({pqueue, [{P, Q} | Queues]}) ->
            end,
     {R, NewQ}.
 
+-spec(shift(pqueue()) -> pqueue()).
+shift(Q = {queue, _, _, _}) ->
+    Q;
+shift({pqueue, []}) ->
+    {pqueue, []}; %% Shouldn't happen?
+shift({pqueue, [Hd|Rest]}) ->
+    {pqueue, Rest ++ [Hd]}. %% Let's hope there are not many priorities.
+
 -spec(out_p(pqueue()) -> {empty | {value, any(), priority()}, pqueue()}).
 out_p({queue, _, _, _}       = Q) -> add_p(out(Q), 0);
 out_p({pqueue, [{P, _} | _]} = Q) -> add_p(out(Q), maybe_negate_priority(P)).
@@ -266,4 +275,3 @@ r2f([X,Y|R], L) -> {queue, [X,Y], lists:reverse(R, []), L}.
 
 maybe_negate_priority(infinity) -> infinity;
 maybe_negate_priority(P)        -> -P.
-

src/emqx_router.erl

@@ -118,7 +118,8 @@ do_add_route(Topic, Dest) when is_binary(Topic) ->
         false ->
             ok = emqx_router_helper:monitor(Dest),
             case emqx_topic:wildcard(Topic) of
-                true  -> trans(fun insert_trie_route/1, [Route]);
+                true  ->
+                    maybe_trans(fun insert_trie_route/1, [Route]);
                 false -> insert_direct_route(Route)
             end
     end.
@@ -164,7 +165,8 @@ do_delete_route(Topic) when is_binary(Topic) ->
 do_delete_route(Topic, Dest) ->
     Route = #route{topic = Topic, dest = Dest},
     case emqx_topic:wildcard(Topic) of
-        true  -> trans(fun delete_trie_route/1, [Route]);
+        true  ->
+            maybe_trans(fun delete_trie_route/1, [Route]);
         false -> delete_direct_route(Route)
     end.
 
@@ -247,10 +249,59 @@ delete_trie_route(Route = #route{topic = Topic}) ->
     end.
 
 %% @private
--spec(trans(function(), list(any())) -> ok | {error, term()}).
+-spec(maybe_trans(function(), list(any())) -> ok | {error, term()}).
-trans(Fun, Args) ->
+maybe_trans(Fun, Args) ->
-    case mnesia:transaction(Fun, Args) of
+    case persistent_term:get(emqx_route_lock_type, key) of
-        {atomic, Ok} -> Ok;
+        key ->
-        {aborted, Reason} -> {error, Reason}
+            trans(Fun, Args);
+        global ->
+            lock_router(),
+            try mnesia:sync_dirty(Fun, Args)
+            after
+                unlock_router()
+            end;
+        tab ->
+            trans(fun() ->
+                          emqx_trie:lock_tables(),
+                          apply(Fun, Args)
+                  end, [])
     end.
 
+-spec(trans(function(), list(any())) -> ok | {error, term()}).
+trans(Fun, Args) ->
+    %% trigger selective receive optimization of compiler,
+    %% ideal for handling bursty traffic.
+    Ref = erlang:make_ref(),
+    Owner = self(),
+    {WPid, RefMon} = spawn_monitor(
+                       fun() ->
+                               Res = case mnesia:transaction(Fun, Args) of
+                                         {atomic, Ok} -> Ok;
+                                         {aborted, Reason} -> {error, Reason}
+                                     end,
+                               Owner ! {Ref, Res}
+                       end),
+    receive
+        {Ref, TransRes} ->
+            receive
+                {'DOWN', RefMon, process, WPid, normal} -> ok
+            end,
+            TransRes;
+        {'DOWN', RefMon, process, WPid, Info} ->
+            {error, {trans_crash, Info}}
+    end.
+
+lock_router() ->
+    %% if Retry is not 0, global:set_lock could sleep a random time up to 8s.
+    %% Considering we have a limited number of brokers, it is safe to use sleep 1 ms.
+    case global:set_lock({?MODULE, self()}, [node() | nodes()], 0) of
+        false ->
+            %% Force to sleep 1ms instead.
+            timer:sleep(1),
+            lock_router();
+        true ->
+            ok
+    end.
+
+unlock_router() ->
+    global:del_lock({?MODULE, self()}).

src/emqx_router_sup.erl

@@ -34,6 +34,10 @@ init([]) ->
                type     => worker,
                modules  => [emqx_router_helper]},
 
+    ok = persistent_term:put(emqx_route_lock_type,
+                             application:get_env(emqx, route_lock_type, key)
+                            ),
+
     %% Router pool
     RouterPool = emqx_pool_sup:spec([router_pool, hash,
                                      {emqx_router, start_link, []}]),

src/emqx_session.erl

@@ -75,6 +75,7 @@
 
 -export([ deliver/2
         , enqueue/2
+        , dequeue/1
         , retry/1
         , terminate/3
         ]).

src/emqx_trie.erl

@@ -31,7 +31,9 @@
         , delete/1
         ]).
 
--export([empty/0]).
+-export([ empty/0
+        , lock_tables/0
+        ]).
 
 -ifdef(TEST).
 -compile(export_all).
@@ -120,6 +122,11 @@ delete(Topic) when is_binary(Topic) ->
 empty() ->
     ets:info(?TRIE_TAB, size) == 0.
 
+-spec lock_tables() -> ok.
+lock_tables() ->
+    mnesia:write_lock_table(?TRIE_TAB),
+    mnesia:write_lock_table(?TRIE_NODE_TAB).
+
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------

src/emqx_ws_connection.erl

@@ -34,7 +34,7 @@
         , stats/1
         ]).
 
--export([call/2]).
+-export([call/2, call/3]).
 
 %% WebSocket callbacks
 -export([ init/2
@@ -63,7 +63,7 @@
           %% Simulate the active_n opt
           active_n :: pos_integer(),
           %% MQTT Piggyback
-          mqtt_piggyback :: single | multiple, 
+          mqtt_piggyback :: single | multiple,
           %% Limiter
           limiter :: maybe(emqx_limiter:limiter()),
           %% Limit Timer
@@ -151,7 +151,10 @@ stats(#state{channel = Channel}) ->
 
 %% kick|discard|takeover
 -spec(call(pid(), Req :: term()) -> Reply :: term()).
-call(WsPid, Req) when is_pid(WsPid) ->
+call(WsPid, Req) ->
+    call(WsPid, Req, 5000).
+
+call(WsPid, Req, Timeout) when is_pid(WsPid) ->
     Mref = erlang:monitor(process, WsPid),
     WsPid ! {call, {self(), Mref}, Req},
     receive
@@ -160,7 +163,7 @@ call(WsPid, Req) when is_pid(WsPid) ->
             Reply;
         {'DOWN', Mref, _, _, Reason} ->
             exit(Reason)
-    after 5000 ->
+    after Timeout ->
         erlang:demonitor(Mref, [flush]),
         exit(timeout)
     end.
@@ -196,15 +199,21 @@ init(Req, Opts) ->
     end.
 
 websocket_init([Req, Opts]) ->
-    Peername = case proplists:get_bool(proxy_protocol, Opts)
+    {Peername, Peercert} =
-                    andalso maps:get(proxy_header, Req) of
+        case proplists:get_bool(proxy_protocol, Opts)
-                   #{src_address := SrcAddr, src_port := SrcPort} ->
+        andalso maps:get(proxy_header, Req) of
-                       {SrcAddr, SrcPort};
+            #{src_address := SrcAddr, src_port := SrcPort, ssl := SSL} ->
-                   _ ->
+                ProxyName = {SrcAddr, SrcPort},
-                       cowboy_req:peer(Req)
+                %% Notice: Only CN is available in Proxy Protocol V2 additional info
-               end,
+                ProxySSL = case maps:get(cn, SSL, undefined) of
+                             undeined -> nossl;
+                             CN -> [{pp2_ssl_cn, CN}]
+                           end,
+                {ProxyName, ProxySSL};
+            _ ->
+                {cowboy_req:peer(Req), cowboy_req:cert(Req)}
+        end,
     Sockname = cowboy_req:sock(Req),
-    Peercert = cowboy_req:cert(Req),
     WsCookie = try cowboy_req:parse_cookies(Req)
                catch
                    error:badarg ->
@@ -477,6 +486,12 @@ parse_incoming(Data, State = #state{parse_state = ParseState}) ->
             NState = State#state{parse_state = NParseState},
             parse_incoming(Rest, postpone({incoming, Packet}, NState))
     catch
+        error:proxy_protocol_config_disabled ->
+            ?LOG(error,
+                 "~nMalformed packet, "
+                 "please check proxy_protocol config for specific listeners and zones~n"),
+            FrameError = {frame_error, proxy_protocol_config_disabled},
+            postpone({incoming, FrameError} ,State);
         error:Reason:Stk ->
             ?LOG(error, "~nParse failed for ~0p~n~0p~nFrame data: ~0p",
                  [Reason, Stk, Data]),
@@ -535,7 +550,7 @@ handle_outgoing(Packets, State = #state{active_n = ActiveN, mqtt_piggyback = MQT
                      postpone({check_gc, Stats}, State);
                  false -> State
              end,
-    
+
     {case MQTTPiggyback of
          single -> [{binary, IoData}];
          multiple -> lists:map(fun(Bin) -> {binary, Bin} end, IoData)
@@ -680,4 +695,3 @@ trigger(Event) -> erlang:send(self(), Event).
 set_field(Name, Value, State) ->
     Pos = emqx_misc:index_of(Name, record_info(fields, state)),
     setelement(Pos+1, State, Value).
-

test/emqx_channel_SUITE.erl

@@ -82,7 +82,7 @@ t_chan_caps(_) ->
      #{max_clientid_len := 65535,
        max_qos_allowed := 2,
        max_topic_alias := 65535,
-       max_topic_levels := 0,
+       max_topic_levels := 128,
        retain_available := true,
        shared_subscription := true,
        subscription_identifiers := true,
@@ -768,4 +768,3 @@ session(InitFields) when is_map(InitFields) ->
 quota() ->
     emqx_limiter:init(zone, [{conn_messages_routing, {5, 1}},
                              {overall_messages_routing, {10, 1}}]).
-

test/emqx_cm_SUITE.erl

@@ -31,6 +31,12 @@
                      conn_mod => emqx_connection,
                      receive_maximum => 100}}).
 
+-define(WAIT(PATTERN, TIMEOUT, RET),
+        fun() ->
+                receive PATTERN -> RET
+                after TIMEOUT -> error({timeout, ?LINE}) end
+        end()).
+
 %%--------------------------------------------------------------------
 %% CT callbacks
 %%--------------------------------------------------------------------
@@ -77,7 +83,7 @@ t_get_set_chan_stats(_) ->
 
 t_open_session(_) ->
     ok = meck:new(emqx_connection, [passthrough, no_history]),
-    ok = meck:expect(emqx_connection, call, fun(_, _) -> ok end),
+    ok = meck:expect(emqx_connection, call, fun(_, _, _) -> ok end),
 
     ClientInfo = #{zone => external,
                    clientid => <<"clientid">>,
@@ -151,19 +157,98 @@ t_open_session_race_condition(_) ->
     exit(Pid, kill), timer:sleep(100),
     ?assertEqual([], emqx_cm:lookup_channels(<<"clientid">>)).
 
-t_discard_session(_) ->
+t_kick_session_discard_normal(_) ->
-    ok = meck:new(emqx_connection, [passthrough, no_history]),
+    test_kick_session(discard, normal).
-    ok = meck:expect(emqx_connection, call, fun(_, _) -> ok end),
+
-    ok = emqx_cm:discard_session(<<"clientid">>),
+t_kick_session_discard_shutdown(_) ->
-    ok = emqx_cm:register_channel(<<"clientid">>, ?ChanInfo, []),
+    test_kick_session(discard, shutdown).
-    ok = emqx_cm:discard_session(<<"clientid">>),
+
-    ok = emqx_cm:unregister_channel(<<"clientid">>),
+t_kick_session_discard_shutdown_with_reason(_) ->
-    ok = emqx_cm:register_channel(<<"clientid">>, ?ChanInfo, []),
+    test_kick_session(discard, {shutdown, discard}).
-    ok = emqx_cm:discard_session(<<"clientid">>),
+
-    ok = meck:expect(emqx_connection, call, fun(_, _) -> error(testing) end),
+t_kick_session_discard_timeout(_) ->
-    ok = emqx_cm:discard_session(<<"clientid">>),
+    test_kick_session(discard, timeout).
-    ok = emqx_cm:unregister_channel(<<"clientid">>),
+
-    ok = meck:unload(emqx_connection).
+t_kick_session_discard_noproc(_) ->
+    test_kick_session(discard, noproc).
+
+t_kick_session_kick_normal(_) ->
+    test_kick_session(discard, normal).
+
+t_kick_session_kick_shutdown(_) ->
+    test_kick_session(discard, shutdown).
+
+t_kick_session_kick_shutdown_with_reason(_) ->
+    test_kick_session(discard, {shutdown, discard}).
+
+t_kick_session_kick_timeout(_) ->
+    test_kick_session(discard, timeout).
+
+t_kick_session_kick_noproc(_) ->
+    test_kick_session(discard, noproc).
+
+test_kick_session(Action, Reason) ->
+    ClientId = rand_client_id(),
+    #{conninfo := ConnInfo} = ?ChanInfo,
+    FakeSessionFun =
+        fun Loop() ->
+                     receive
+                         {'$gen_call', From, A} when A =:= kick orelse
+                                                     A =:= discard ->
+                             case Reason of
+                                 normal ->
+                                     gen_server:reply(From, ok);
+                                 timeout ->
+                                     %% no response to the call
+                                     Loop();
+                                 _ ->
+                                     exit(Reason)
+                             end;
+                         Msg ->
+                             ct:pal("(~p) fake_session_discarded ~p", [Action, Msg]),
+                             Loop()
+                     end
+        end,
+    {Pid1, _} = spawn_monitor(FakeSessionFun),
+    {Pid2, _} = spawn_monitor(FakeSessionFun),
+    ok = emqx_cm:register_channel_(ClientId, Pid1, ConnInfo),
+    ok = emqx_cm:register_channel_(ClientId, Pid1, ConnInfo),
+    ok = emqx_cm:register_channel_(ClientId, Pid2, ConnInfo),
+    ?assertEqual([Pid1, Pid2], lists:sort(emqx_cm:lookup_channels(ClientId))),
+    case Reason of
+        noproc -> exit(Pid1, kill), exit(Pid2, kill);
+        _ -> ok
+    end,
+    ok = case Action of
+             kick -> emqx_cm:kick_session(ClientId);
+             discard -> emqx_cm:discard_session(ClientId)
+         end,
+    case Reason =:= timeout orelse Reason =:= noproc of
+        true ->
+            ?assertEqual(killed, ?WAIT({'DOWN', _, process, Pid1, R}, 2000, R)),
+            ?assertEqual(killed, ?WAIT({'DOWN', _, process, Pid2, R}, 2000, R));
+        false ->
+            ?assertEqual(Reason, ?WAIT({'DOWN', _, process, Pid1, R}, 2000, R)),
+            ?assertEqual(Reason, ?WAIT({'DOWN', _, process, Pid2, R}, 2000, R))
+    end,
+    ok = flush_emqx_pool(),
+    ?assertEqual([], emqx_cm:lookup_channels(ClientId)).
+
+rand_client_id() ->
+    list_to_binary("client-id-" ++ integer_to_list(erlang:system_time())).
+
+%% Channel deregistration is delegated to emqx_pool as a sync tasks.
+%% The emqx_pool is pool of workers, and there is no way to know
+%% which worker was picked for the last deregistration task.
+%% This help function creates a large enough number of async tasks
+%% to sync with the pool workers.
+%% The number of tasks should be large enough to ensure all workers have
+%% the chance to work on at least one of the tasks.
+flush_emqx_pool() ->
+    Self = self(),
+    L = lists:seq(1, 1000),
+    lists:foreach(fun(I) -> emqx_pool:async_submit(fun() -> Self ! {done, I} end, []) end, L),
+    lists:foreach(fun(I) -> receive {done, I} -> ok end end, L).
 
 t_takeover_session(_) ->
     {error, not_found} = emqx_cm:takeover_session(<<"clientid">>),
@@ -178,21 +263,6 @@ t_takeover_session(_) ->
     {ok, emqx_connection, _, test} = emqx_cm:takeover_session(<<"clientid">>),
     emqx_cm:unregister_channel(<<"clientid">>).
 
-t_kick_session(_) ->
-    ok = meck:new(emqx_connection, [passthrough, no_history]),
-    ok = meck:expect(emqx_connection, call, fun(_, _) -> test end),
-    {error, not_found} = emqx_cm:kick_session(<<"clientid">>),
-    ok = emqx_cm:register_channel(<<"clientid">>, ?ChanInfo, []),
-    test = emqx_cm:kick_session(<<"clientid">>),
-    erlang:spawn(fun() ->
-                     ok = emqx_cm:register_channel(<<"clientid">>, ?ChanInfo, []),
-                     timer:sleep(1000)
-                 end),
-    ct:sleep(100),
-    test = emqx_cm:kick_session(<<"clientid">>),
-    ok = emqx_cm:unregister_channel(<<"clientid">>),
-    ok = meck:unload(emqx_connection).
-
 t_all_channels(_) ->
     ?assertEqual(true, is_list(emqx_cm:all_channels())).
 

test/emqx_frame_SUITE.erl

@@ -42,7 +42,11 @@ all() ->
 groups() ->
     [{parse, [parallel],
       [t_parse_cont,
-       t_parse_frame_too_large
+       t_parse_frame_too_large,
+       t_parse_frame_malformed_variable_byte_integer,
+       t_parse_frame_variable_byte_integer,
+       t_parse_malformed_utf8_string,
+       t_parse_frame_proxy_protocol %% proxy_protocol_config_disabled packet.
       ]},
      {connect, [parallel],
       [t_serialize_parse_v3_connect,
@@ -129,6 +133,41 @@ t_parse_frame_too_large(_) ->
     ?catch_error(frame_too_large, parse_serialize(Packet, #{max_size => 512})),
     ?assertEqual(Packet, parse_serialize(Packet, #{max_size => 2048, version => ?MQTT_PROTO_V4})).
 
+t_parse_frame_malformed_variable_byte_integer(_) ->
+    MalformedPayload = << <<16#80>> || _ <- lists:seq(1, 4) >>,
+    ParseState = emqx_frame:initial_parse_state(#{}),
+    ?catch_error(malformed_variable_byte_integer,
+        emqx_frame:parse(MalformedPayload, ParseState)).
+
+t_parse_frame_variable_byte_integer(_) ->
+    Bin = <<2#10010011, 2#10000000, 2#10001000, 2#10011001, 2#10101101, 2#00110010>>,
+    ?catch_error(malformed_variable_byte_integer,
+        emqx_frame:parse_variable_byte_integer(Bin)).
+
+t_parse_malformed_utf8_string(_) ->
+    MalformedPacket = <<16,31,0,4,
+                        %% Specification name, should be "MQTT"
+                        %% 77,81,84,84,
+                        %% malformed 1-Byte UTF-8 in (U+0000 .. U+001F] && [U+007F])
+                        16#00,16#01,16#1F,16#7F,
+
+                        4,194,0,60,
+                        0,4,101,109,
+                        113,120,0,5,
+                        97,100,109,105,
+                        110,0,6,112,
+                        117,98,108,105,
+                        99>>,
+    ParseState = emqx_frame:initial_parse_state(#{strict_mode => true}),
+    ?catch_error(utf8_string_invalid, emqx_frame:parse(MalformedPacket, ParseState)).
+
+t_parse_frame_proxy_protocol(_) ->
+    BinList = [ <<"PROXY TCP4 ">>, <<"PROXY TCP6 ">>, <<"PROXY UNKNOWN">>
+              , <<"\r\n\r\n\0\r\nQUIT\n">>],
+    [?assertError( proxy_protocol_config_disabled
+                 , emqx_frame:parse(Bin))
+     || Bin <- BinList].
+
 t_serialize_parse_v3_connect(_) ->
     Bin = <<16,37,0,6,77,81,73,115,100,112,3,2,0,60,0,23,109,111,115,
             113,112,117, 98,47,49,48,52,53,49,45,105,77,97,99,46,108,
@@ -524,4 +563,3 @@ parse_to_packet(Bin, Opts) ->
     Packet.
 
 payload(Len) -> iolist_to_binary(lists:duplicate(Len, 1)).
-

test/emqx_os_mon_SUITE.erl

@@ -24,10 +24,23 @@
 all() -> emqx_ct:all(?MODULE).
 
 init_per_suite(Config) ->
+    emqx_ct_helpers:boot_modules(all),
+    emqx_ct_helpers:start_apps([],
+        fun(emqx) ->
+            application:set_env(emqx, os_mon, [
+                {cpu_check_interval, 1},
+                {cpu_high_watermark, 5},
+                {cpu_low_watermark, 80},
+                {mem_check_interval, 60},
+                {sysmem_high_watermark, 70},
+                {procmem_high_watermark, 5}]);
+            (_) -> ok
+        end),
     application:ensure_all_started(os_mon),
     Config.
 
 end_per_suite(_Config) ->
+    emqx_ct_helpers:stop_apps([]),
     application:stop(os_mon).
 
 % t_set_mem_check_interval(_) ->
@@ -40,13 +53,6 @@ end_per_suite(_Config) ->
 %     error('TODO').
 
 t_api(_) ->
-    gen_event:swap_handler(alarm_handler, {emqx_alarm_handler, swap}, {alarm_handler, []}),
-    {ok, _} = emqx_os_mon:start_link([{cpu_check_interval, 1},
-                                      {cpu_high_watermark, 5},
-                                      {cpu_low_watermark, 80},
-                                      {mem_check_interval, 60},
-                                      {sysmem_high_watermark, 70},
-                                      {procmem_high_watermark, 5}]),
     ?assertEqual(1, emqx_os_mon:get_cpu_check_interval()),
     ?assertEqual(5, emqx_os_mon:get_cpu_high_watermark()),
     ?assertEqual(80, emqx_os_mon:get_cpu_low_watermark()),
@@ -69,4 +75,3 @@ t_api(_) ->
     emqx_os_mon ! ignored,
     gen_server:stop(emqx_os_mon),
     ok.
-

test/mqtt_protocol_v5_SUITE.erl

@@ -270,7 +270,7 @@ t_connect_limit_timeout(_) ->
     meck:unload(proplists).
 
 t_connect_emit_stats_timeout(_) ->
-    IdleTimeout = 2000,
+    IdleTimeout = 2000 + 200,
     emqx_zone:set_env(external, idle_timeout, IdleTimeout),
 
     {ok, Client} = emqtt:start_link([{proto_ver, v5},{keepalive, 60}]),
@@ -278,7 +278,7 @@ t_connect_emit_stats_timeout(_) ->
     [ClientPid] = emqx_cm:lookup_channels(client_info(clientid, Client)),
 
     ?assert(is_reference(emqx_connection:info(stats_timer, sys:get_state(ClientPid)))),
-    timer:sleep(IdleTimeout),
+    timer:sleep(IdleTimeout+500),
     ?assertEqual(undefined, emqx_connection:info(stats_timer, sys:get_state(ClientPid))),
     ok = emqtt:disconnect(Client).