diff --git a/apps/db_dump/Makefile b/apps/db_dump/Makefile
index c9d58522..74fe0517 100644
--- a/apps/db_dump/Makefile
+++ b/apps/db_dump/Makefile
@@ -1,7 +1,7 @@
 R=../..
 include ${R}/config.mk
 
-CFLAGS_FINAL=${CFLAGS} -I${R}/include -I${R}/ -I${R}/lib -I${R}/src -I${R}/deps -DWITH_BROKER -DWITH_PERSISTENCE
+CFLAGS_FINAL=${CFLAGS} -I${R}/include -I${R}/ -I${R}/lib -I${R}/src -I${R}/deps -I${R}/common -DWITH_BROKER -DWITH_PERSISTENCE
 
 OBJS = \
 	   db_dump.o \
@@ -70,7 +70,7 @@ stubs.o : stubs.c
 send_disconnect.o : ${R}/lib/send_disconnect.c
 	${CROSS_COMPILE}${CC} $(CFLAGS_FINAL) -c $< -o $@
 
-time_mosq.o : ${R}/lib/time_mosq.c
+time_mosq.o : ${R}/common/time_mosq.c ${R}/common/time_mosq.h
 	${CROSS_COMPILE}${CC} $(CFLAGS_FINAL) -c $< -o $@
 
 topic_tok.o : ${R}/src/topic_tok.c
diff --git a/apps/mosquitto_ctrl/CMakeLists.txt b/apps/mosquitto_ctrl/CMakeLists.txt
index 2aaca663..c203b757 100644
--- a/apps/mosquitto_ctrl/CMakeLists.txt
+++ b/apps/mosquitto_ctrl/CMakeLists.txt
@@ -5,7 +5,7 @@ if(WITH_TLS AND CJSON_FOUND)
 
 	add_executable(mosquitto_ctrl
 		mosquitto_ctrl.c mosquitto_ctrl.h
-		../../lib/base64_mosq.c ../../lib/base64_mosq.h
+		../../common/base64_mosq.c ../../common/base64_mosq.h
 		broker.c
 		client.c
 		dynsec.c
@@ -17,7 +17,7 @@ if(WITH_TLS AND CJSON_FOUND)
 		../../lib/memory_mosq.c ../../lib/memory_mosq.h
 		../../src/memory_public.c
 		options.c
-		../../src/password_mosq.c ../../src/password_mosq.h
+		../../common/password_mosq.c ../../common/password_mosq.h
 	)
 
 	target_include_directories(mosquitto_ctrl PRIVATE
@@ -27,10 +27,11 @@ if(WITH_TLS AND CJSON_FOUND)
 		"${STDINT_H_PATH}"
 		"${mosquitto_SOURCE_DIR}"
 		"${mosquitto_SOURCE_DIR}/apps/mosquitto_passwd"
+		"${mosquitto_SOURCE_DIR}/common"
 		"${mosquitto_SOURCE_DIR}/include"
 		"${mosquitto_SOURCE_DIR}/lib"
+		"${mosquitto_SOURCE_DIR}/plugins/common"
 		"${mosquitto_SOURCE_DIR}/plugins/dynamic-security"
-		"${mosquitto_SOURCE_DIR}/plugins/shared"
 		"${mosquitto_SOURCE_DIR}/src"
 	)
 	if(WITH_BUNDLED_DEPS)
diff --git a/apps/mosquitto_ctrl/Makefile b/apps/mosquitto_ctrl/Makefile
index 477a15a7..bcf1ef43 100644
--- a/apps/mosquitto_ctrl/Makefile
+++ b/apps/mosquitto_ctrl/Makefile
@@ -13,7 +13,7 @@ LIBMOSQ:=${R}/lib/libmosquitto.a
 endif
 endif
 
-LOCAL_CPPFLAGS:=-I${R}/apps/mosquitto_passwd -I${R}/plugins/dynamic-security -DWITH_CJSON -I${R}/plugins/shared
+LOCAL_CPPFLAGS:=-I${R}/apps/mosquitto_passwd -I${R}/plugins/dynamic-security -DWITH_CJSON -I${R}/plugins/common -I${R}/common
 ifeq ($(WITH_BUNDLED_DEPS),yes)
 LOCAL_CPPFLAGS+=-I${R}/deps
 endif
@@ -57,7 +57,7 @@ mosquitto_ctrl_example.so : ${EXAMPLE_OBJS}
 mosquitto_ctrl.o : mosquitto_ctrl.c mosquitto_ctrl.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
-base64_mosq.o : ${R}/lib/base64_mosq.c ${R}/lib/base64_mosq.h
+base64_mosq.o : ${R}/common/base64_mosq.c ${R}/common/base64_mosq.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
 broker.o : broker.c mosquitto_ctrl.h
@@ -99,7 +99,7 @@ options.o : options.c mosquitto_ctrl.h
 misc_mosq.o : ${R}/lib/misc_mosq.c ${R}/lib/misc_mosq.h
 	${CROSS_COMPILE}${CC} $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
-password_mosq.o : ${R}/src/password_mosq.c ${R}/src/password_mosq.h
+password_mosq.o : ${R}/common/password_mosq.c ${R}/common/password_mosq.h
 	${CROSS_COMPILE}${CC} $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
 ${R}/lib/libmosquitto.so.${SOVERSION} :
diff --git a/apps/mosquitto_passwd/CMakeLists.txt b/apps/mosquitto_passwd/CMakeLists.txt
index b62b4453..42198c46 100644
--- a/apps/mosquitto_passwd/CMakeLists.txt
+++ b/apps/mosquitto_passwd/CMakeLists.txt
@@ -2,11 +2,11 @@ if(WITH_TLS)
 	add_executable(mosquitto_passwd
 		mosquitto_passwd.c
 		get_password.c get_password.h
-		../../lib/base64_mosq.c ../../lib/base64_mosq.h
+		../../common/base64_mosq.c ../../common/base64_mosq.h
 		../../lib/memory_mosq.c ../../lib/memory_mosq.h
 		../../src/memory_public.c
-		../../lib/misc_mosq.c
-		../../src/password_mosq.c ../../src/password_mosq.h
+		../../common/misc_mosq.c ../../common/misc_mosq.h
+		../../common/password_mosq.c ../../common/password_mosq.h
 	)
 
 	target_include_directories(mosquitto_passwd PRIVATE
@@ -14,6 +14,7 @@ if(WITH_TLS)
 		"${STDBOOL_H_PATH}"
 		"${STDINT_H_PATH}"
 		"${mosquitto_SOURCE_DIR}"
+		"${mosquitto_SOURCE_DIR}/common"
 		"${mosquitto_SOURCE_DIR}/include"
 		"${mosquitto_SOURCE_DIR}/lib"
 		"${mosquitto_SOURCE_DIR}/src"
diff --git a/apps/mosquitto_passwd/Makefile b/apps/mosquitto_passwd/Makefile
index b85adfb0..82ffad93 100644
--- a/apps/mosquitto_passwd/Makefile
+++ b/apps/mosquitto_passwd/Makefile
@@ -26,7 +26,7 @@ mosquitto_passwd.o : mosquitto_passwd.c
 get_password.o : get_password.c
 	${CROSS_COMPILE}${CC} $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
-base64_mosq.o : ${R}/lib/base64_mosq.c ${R}/lib/base64_mosq.h
+base64_mosq.o : ${R}/common/base64_mosq.c ${R}/common/base64_mosq.h
 	${CROSS_COMPILE}${CC} $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
 memory_mosq.o : ${R}/lib/memory_mosq.c
@@ -35,10 +35,10 @@ memory_mosq.o : ${R}/lib/memory_mosq.c
 memory_public.o : ${R}/src/memory_public.c
 	${CROSS_COMPILE}${CC} $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
-misc_mosq.o : ${R}/lib/misc_mosq.c ${R}/lib/misc_mosq.h
+misc_mosq.o : ${R}/common/misc_mosq.c ${R}/common/misc_mosq.h
 	${CROSS_COMPILE}${CC} $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
-password_mosq.o : ${R}/src/password_mosq.c ${R}/src/password_mosq.h
+password_mosq.o : ${R}/common/password_mosq.c ${R}/common/password_mosq.h
 	${CROSS_COMPILE}${CC} $(APP_CPPFLAGS) $(APP_CFLAGS) -c $< -o $@
 
 install : all
diff --git a/lib/base64_mosq.c b/common/base64_mosq.c
similarity index 100%
rename from lib/base64_mosq.c
rename to common/base64_mosq.c
diff --git a/lib/base64_mosq.h b/common/base64_mosq.h
similarity index 100%
rename from lib/base64_mosq.h
rename to common/base64_mosq.h
diff --git a/src/json_help.c b/common/json_help.c
similarity index 100%
rename from src/json_help.c
rename to common/json_help.c
diff --git a/src/json_help.h b/common/json_help.h
similarity index 100%
rename from src/json_help.h
rename to common/json_help.h
diff --git a/src/lib_load.h b/common/lib_load.h
similarity index 100%
rename from src/lib_load.h
rename to common/lib_load.h
diff --git a/lib/misc_mosq.c b/common/misc_mosq.c
similarity index 100%
rename from lib/misc_mosq.c
rename to common/misc_mosq.c
diff --git a/lib/misc_mosq.h b/common/misc_mosq.h
similarity index 100%
rename from lib/misc_mosq.h
rename to common/misc_mosq.h
diff --git a/src/password_mosq.c b/common/password_mosq.c
similarity index 100%
rename from src/password_mosq.c
rename to common/password_mosq.c
diff --git a/src/password_mosq.h b/common/password_mosq.h
similarity index 100%
rename from src/password_mosq.h
rename to common/password_mosq.h
diff --git a/lib/time_mosq.c b/common/time_mosq.c
similarity index 100%
rename from lib/time_mosq.c
rename to common/time_mosq.c
diff --git a/lib/time_mosq.h b/common/time_mosq.h
similarity index 100%
rename from lib/time_mosq.h
rename to common/time_mosq.h
diff --git a/lib/winthread_mosq.c b/common/winthread_mosq.c
similarity index 100%
rename from lib/winthread_mosq.c
rename to common/winthread_mosq.c
diff --git a/lib/winthread_mosq.h b/common/winthread_mosq.h
similarity index 100%
rename from lib/winthread_mosq.h
rename to common/winthread_mosq.h
diff --git a/config.mk b/config.mk
index 3235269b..d3a55eda 100644
--- a/config.mk
+++ b/config.mk
@@ -169,17 +169,17 @@ endif
 
 STATIC_LIB_DEPS:=
 
-APP_CPPFLAGS=$(CPPFLAGS) -I. -I../../ -I../../include -I../../src -I../../lib
+APP_CPPFLAGS=$(CPPFLAGS) -I. -I${R}/ -I${R}/include -I${R}/common -I${R}/lib
 APP_CFLAGS=$(CFLAGS) -DVERSION=\""${VERSION}\""
 APP_LDFLAGS:=$(LDFLAGS)
 
-LIB_CPPFLAGS=$(CPPFLAGS) -I. -I.. -I../include -I../../include
+LIB_CPPFLAGS=$(CPPFLAGS) -I${R}/ -I. -I${R}/common -I${R}/include -I${R}/lib
 LIB_CFLAGS:=$(CFLAGS)
 LIB_CXXFLAGS:=$(CXXFLAGS)
 LIB_LDFLAGS:=$(LDFLAGS)
 LIB_LIBADD:=$(LIBADD)
 
-BROKER_CPPFLAGS:=$(LIB_CPPFLAGS) -I../lib
+BROKER_CPPFLAGS:=$(LIB_CPPFLAGS) -I../lib -I../common
 BROKER_CFLAGS:=${CFLAGS} -DVERSION="\"${VERSION}\"" -DWITH_BROKER
 BROKER_LDFLAGS:=${LDFLAGS}
 BROKER_LDADD:=
@@ -191,7 +191,7 @@ CLIENT_LDADD:=
 
 PASSWD_LDADD:=
 
-PLUGIN_CPPFLAGS:=$(CPPFLAGS) -I../.. -I../../include
+PLUGIN_CPPFLAGS:=$(CPPFLAGS) -I${R} -I${R}/include -I${R}/common -I${R}/plugins/common
 PLUGIN_CFLAGS:=$(CFLAGS) -fPIC
 PLUGIN_LDFLAGS:=$(LDFLAGS)
 
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 9645164d..31da76f9 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -26,7 +26,7 @@ set(C_SRC
 	loop.c
 	memory_mosq.c memory_mosq.h
 	messages_mosq.c messages_mosq.h
-	misc_mosq.c misc_mosq.h
+	../common/misc_mosq.c ../common/misc_mosq.h
 	mosquitto.c ../include/mosquitto.h
 	mosquitto_internal.h
 	../include/mqtt_protocol.h
@@ -48,14 +48,14 @@ set(C_SRC
 	srv_mosq.c
 	strings_mosq.c
 	thread_mosq.c
-	time_mosq.c
+	../common/time_mosq.c ../common/time_mosq.h
 	tls_mosq.c
 	utf8_mosq.c
 	util_mosq.c util_topic.c util_mosq.h
 	will_mosq.c will_mosq.h)
 
 if (WIN32)
-	list(APPEND C_SRC "winthread_mosq.c" "winthread_mosq.h")
+	list(APPEND C_SRC "../common/winthread_mosq.c" "../common/winthread_mosq.h")
 endif()
 
 set (LIBRARIES ${OPENSSL_LIBRARIES} ${PTHREAD_LIBRARIES})
@@ -86,7 +86,7 @@ if(WITH_WEBSOCKETS AND WITH_WEBSOCKETS_BUILTIN)
 	add_definitions("-DWITH_WEBSOCKETS=WS_IS_BUILTIN")
 	set(C_SRC ${C_SRC}
 		../deps/picohttpparser/picohttpparser.c
-		base64_mosq.c base64_mosq.h
+		../common/base64_mosq.c ../common/base64_mosq.h
 		http_client.c http_client.h
 		net_ws.c
 		)
@@ -107,6 +107,7 @@ target_include_directories(libmosquitto PRIVATE
 	"${STDBOOL_H_PATH}"
 	"${STDINT_H_PATH}"
 	"${mosquitto_SOURCE_DIR}"
+	"${mosquitto_SOURCE_DIR}/common"
 	"${mosquitto_SOURCE_DIR}/include"
 	"${mosquitto_SOURCE_DIR}/lib"
 )
diff --git a/lib/Makefile b/lib/Makefile
index 358d1491..6affa58b 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -128,7 +128,7 @@ alias_mosq.o : alias_mosq.c alias_mosq.h ${R}/include/mosquitto.h mosquitto_inte
 callbacks.o : callbacks.c ${R}/include/mosquitto.h mosquitto_internal.h
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
-base64_mosq.o : base64_mosq.c base64_mosq.h
+base64_mosq.o : ${R}/common/base64_mosq.c ${R}/common/base64_mosq.h
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
 connect.o : connect.c ${R}/include/mosquitto.h mosquitto_internal.h
@@ -182,7 +182,7 @@ messages_mosq.o : messages_mosq.c messages_mosq.h
 memory_mosq.o : memory_mosq.c memory_mosq.h
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
-misc_mosq.o : misc_mosq.c misc_mosq.h
+misc_mosq.o : ${R}/common/misc_mosq.c ${R}/common/misc_mosq.h
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
 net_mosq_ocsp.o : net_mosq_ocsp.c net_mosq.h
@@ -191,7 +191,7 @@ net_mosq_ocsp.o : net_mosq_ocsp.c net_mosq.h
 net_mosq.o : net_mosq.c net_mosq.h
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
-password_mosq.o : ${R}/src/password_mosq.c net_mosq.h
+password_mosq.o : ${R}/common/password_mosq.c net_mosq.h
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
 picohttpparser.o : ${R}/deps/picohttpparser/picohttpparser.c ${R}/deps/picohttpparser/picohttpparser.h
@@ -245,7 +245,7 @@ strings_mosq.o : strings_mosq.c
 thread_mosq.o : thread_mosq.c
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
-time_mosq.o : time_mosq.c
+time_mosq.o : ${R}/common/time_mosq.c ${R}/common/time_mosq.h
 	${CROSS_COMPILE}$(CC) $(LIB_CPPFLAGS) $(LIB_CFLAGS) -c $< -o $@
 
 tls_mosq.o : tls_mosq.c
diff --git a/plugins/shared/plugin_shared.c b/plugins/common/plugin_common.c
similarity index 95%
rename from plugins/shared/plugin_shared.c
rename to plugins/common/plugin_common.c
index 32a97162..08bccd9e 100644
--- a/plugins/shared/plugin_shared.c
+++ b/plugins/common/plugin_common.c
@@ -1,5 +1,5 @@
 #include <cjson/cJSON.h>
-#include "plugin_shared.h"
+#include "plugin_common.h"
 
 void plugin__command_reply(struct plugin_cmd *cmd, const char *error)
 {
diff --git a/plugins/shared/plugin_shared.h b/plugins/common/plugin_common.h
similarity index 100%
rename from plugins/shared/plugin_shared.h
rename to plugins/common/plugin_common.h
diff --git a/plugins/dynamic-security/CMakeLists.txt b/plugins/dynamic-security/CMakeLists.txt
index c5072c0e..cb371cc9 100644
--- a/plugins/dynamic-security/CMakeLists.txt
+++ b/plugins/dynamic-security/CMakeLists.txt
@@ -8,10 +8,11 @@ if(CJSON_FOUND AND WITH_TLS)
 		"${STDBOOL_H_PATH}"
 		"${STDINT_H_PATH}"
 		"${mosquitto_SOURCE_DIR}"
+		"${mosquitto_SOURCE_DIR}/common"
 		"${mosquitto_SOURCE_DIR}/deps"
 		"${mosquitto_SOURCE_DIR}/include"
 		"${mosquitto_SOURCE_DIR}/lib"
-		"${mosquitto_SOURCE_DIR}/plugins/shared"
+		"${mosquitto_SOURCE_DIR}/plugins/common"
 		"${mosquitto_SOURCE_DIR}/src"
 	)
 
@@ -20,7 +21,7 @@ if(CJSON_FOUND AND WITH_TLS)
 	add_library(mosquitto_dynamic_security MODULE
 		acl.c
 		auth.c
-		../../lib/base64_mosq.c ../../lib/base64_mosq.h
+		../../common/base64_mosq.c ../../common/base64_mosq.h
 		clients.c
 		clientlist.c
 		config.c
@@ -31,11 +32,11 @@ if(CJSON_FOUND AND WITH_TLS)
 		groups.c
 		grouplist.c
 		hash.c
-		../shared/json_help.c ../shared/json_help.h
-		../../lib/misc_mosq.c ../../lib/misc_mosq.h
-		../../src/password_mosq.c ../../src/password_mosq.h
+		../../common/json_help.c ../../common/json_help.h
+		../../common/misc_mosq.c ../../common/misc_mosq.h
+		../../common/password_mosq.c ../../common/password_mosq.h
 		plugin.c
-		../shared/plugin_shared.c ../shared/plugin_shared.h
+		../common/plugin_common.c ../common/plugin_common.h
 		roles.c
 		rolelist.c
 	)
diff --git a/plugins/dynamic-security/Makefile b/plugins/dynamic-security/Makefile
index 82ae66bb..e49f2383 100644
--- a/plugins/dynamic-security/Makefile
+++ b/plugins/dynamic-security/Makefile
@@ -4,7 +4,7 @@ include ${R}/config.mk
 .PHONY : all binary check clean reallyclean test install uninstall
 
 PLUGIN_NAME=mosquitto_dynamic_security
-LOCAL_CPPFLAGS=-I${R}/lib/ -I${R}/src/ -I${R}/plugins/shared -DWITH_CJSON -DWITH_TLS
+LOCAL_CPPFLAGS=-I${R}/lib/ -I${R}/src/ -I${R}/plugins/common -DWITH_CJSON -DWITH_TLS
 ifeq ($(WITH_BUNDLED_DEPS),yes)
 	LOCAL_CPPFLAGS:=$(LOCAL_CPPFLAGS) -I${R}/deps
 endif
@@ -26,7 +26,7 @@ OBJS=	\
 		misc_mosq.o \
 		password_mosq.o \
 		plugin.o \
-		plugin_shared.o \
+		plugin_common.o \
 		roles.o \
 		rolelist.o
 
@@ -52,7 +52,7 @@ acl.o : acl.c dynamic_security.h
 auth.o : auth.c dynamic_security.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
-base64_mosq.o : ${R}/lib/base64_mosq.c ${R}/lib/base64_mosq.h
+base64_mosq.o : ${R}/common/base64_mosq.c ${R}/common/base64_mosq.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
 clients.o : clients.c dynamic_security.h
@@ -82,19 +82,19 @@ grouplist.o : grouplist.c dynamic_security.h
 hash.o : hash.c dynamic_security.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
-json_help.o : ${R}/plugins/shared/json_help.c ${R}/plugins/shared/json_help.h
+json_help.o : ${R}/common/json_help.c ${R}/common/json_help.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
-misc_mosq.o : ${R}/lib/misc_mosq.c dynamic_security.h
+misc_mosq.o : ${R}/common/misc_mosq.c ${R}/common/misc_mosq.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
-password_mosq.o : ${R}/src/password_mosq.c dynamic_security.h
+password_mosq.o : ${R}/common/password_mosq.c ${R}/common/password_mosq.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
 plugin.o : plugin.c dynamic_security.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
-plugin_shared.o : ${R}/plugins/shared/plugin_shared.c dynamic_security.h
+plugin_common.o : ${R}/plugins/common/plugin_common.c dynamic_security.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) -c $< -o $@
 
 roles.o : roles.c dynamic_security.h
diff --git a/plugins/dynamic-security/default_acl.c b/plugins/dynamic-security/default_acl.c
index 5f87ad4d..042e36f1 100644
--- a/plugins/dynamic-security/default_acl.c
+++ b/plugins/dynamic-security/default_acl.c
@@ -30,7 +30,7 @@ Contributors:
 #include "mosquitto_broker.h"
 #include "mosquitto_plugin.h"
 #include "mqtt_protocol.h"
-#include "plugin_shared.h"
+#include "plugin_common.h"
 
 #include "dynamic_security.h"
 
diff --git a/plugins/dynamic-security/dynamic_security.h b/plugins/dynamic-security/dynamic_security.h
index 5e0391d2..16508cd9 100644
--- a/plugins/dynamic-security/dynamic_security.h
+++ b/plugins/dynamic-security/dynamic_security.h
@@ -23,7 +23,7 @@ Contributors:
 #include "mosquitto.h"
 #include "password_mosq.h"
 #include "base64_mosq.h"
-#include "plugin_shared.h"
+#include "plugin_common.h"
 
 /* ################################################################
  * #
diff --git a/plugins/shared/json_help.c b/plugins/shared/json_help.c
deleted file mode 100644
index a1ca3bc3..00000000
--- a/plugins/shared/json_help.c
+++ /dev/null
@@ -1,103 +0,0 @@
-/*
-Copyright (c) 2020-2021 Roger Light <roger@atchoo.org>
-
-All rights reserved. This program and the accompanying materials
-are made available under the terms of the Eclipse Public License 2.0
-and Eclipse Distribution License v1.0 which accompany this distribution.
-
-The Eclipse Public License is available at
-   https://www.eclipse.org/legal/epl-2.0/
-and the Eclipse Distribution License is available at
-  http://www.eclipse.org/org/documents/edl-v10.php.
-
-SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
-
-Contributors:
-   Roger Light - initial implementation and documentation.
-*/
-
-#include "config.h"
-
-#include <cjson/cJSON.h>
-#include <stdbool.h>
-#include <stdlib.h>
-#include <stdio.h>
-
-#include "json_help.h"
-#include "mosquitto.h"
-
-
-int json_get_bool(cJSON *json, const char *name, bool *value, bool optional, bool default_value)
-{
-	cJSON *jtmp;
-
-	if(optional == true){
-		*value = default_value;
-	}
-
-	jtmp = cJSON_GetObjectItem(json, name);
-	if(jtmp){
-		if(cJSON_IsBool(jtmp) == false){
-			return MOSQ_ERR_INVAL;
-		}
-		*value = cJSON_IsTrue(jtmp);
-	}else{
-		if(optional == false){
-			return MOSQ_ERR_INVAL;
-		}
-	}
-	return MOSQ_ERR_SUCCESS;
-}
-
-
-int json_get_int(cJSON *json, const char *name, int *value, bool optional, int default_value)
-{
-	cJSON *jtmp;
-
-	if(optional == true){
-		*value = default_value;
-	}
-
-	jtmp = cJSON_GetObjectItem(json, name);
-	if(jtmp){
-		if(cJSON_IsNumber(jtmp) == false){
-			return MOSQ_ERR_INVAL;
-		}
-		*value  = jtmp->valueint;
-	}else{
-		if(optional == false){
-			return MOSQ_ERR_INVAL;
-		}
-	}
-	return MOSQ_ERR_SUCCESS;
-}
-
-
-int json_get_string(cJSON *json, const char *name, char **value, bool optional)
-{
-	cJSON *jtmp;
-
-	*value = NULL;
-
-	jtmp = cJSON_GetObjectItem(json, name);
-	if(jtmp){
-		if(cJSON_IsString(jtmp) == false){
-			return MOSQ_ERR_INVAL;
-		}
-		*value  = jtmp->valuestring;
-	}else{
-		if(optional == false){
-			return MOSQ_ERR_INVAL;
-		}
-	}
-	return MOSQ_ERR_SUCCESS;
-}
-
-
-cJSON *cJSON_AddIntToObject(cJSON * const object, const char * const name, int number)
-{
-	char buf[30];
-
-	snprintf(buf, sizeof(buf), "%d", number);
-	return cJSON_AddRawToObject(object, name, buf);
-}
diff --git a/plugins/shared/json_help.h b/plugins/shared/json_help.h
deleted file mode 100644
index c921f210..00000000
--- a/plugins/shared/json_help.h
+++ /dev/null
@@ -1,31 +0,0 @@
-#ifndef JSON_HELP_H
-#define JSON_HELP_H
-/*
-Copyright (c) 2020-2021 Roger Light <roger@atchoo.org>
-
-All rights reserved. This program and the accompanying materials
-are made available under the terms of the Eclipse Public License 2.0
-and Eclipse Distribution License v1.0 which accompany this distribution.
-
-The Eclipse Public License is available at
-   https://www.eclipse.org/legal/epl-2.0/
-and the Eclipse Distribution License is available at
-  http://www.eclipse.org/org/documents/edl-v10.php.
-
-SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
-
-Contributors:
-   Roger Light - initial implementation and documentation.
-*/
-#include <cjson/cJSON.h>
-#include <stdbool.h>
-
-/* "optional==false" can also be taken to mean "only return success if the key exists and is valid" */
-int json_get_bool(cJSON *json, const char *name, bool *value, bool optional, bool default_value);
-int json_get_int(cJSON *json, const char *name, int *value, bool optional, int default_value);
-int json_get_string(cJSON *json, const char *name, char **value, bool optional);
-
-cJSON *cJSON_AddIntToObject(cJSON * const object, const char * const name, int number);
-cJSON *cJSON_CreateInt(int num);
-
-#endif
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index cccf0f4c..9bb48d5c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,6 +1,6 @@
 set (MOSQ_SRCS
 	../lib/alias_mosq.c ../lib/alias_mosq.h
-	../lib/base64_mosq.c
+	../common/base64_mosq.c ../common/base64_mosq.h
 	bridge.c bridge_topic.c
 	broker_control.c
 	conf.c
@@ -22,9 +22,9 @@ set (MOSQ_SRCS
 	../lib/handle_unsuback.c
 	handle_unsubscribe.c
 	http_serv.c
-	json_help.c json_help.h
+	../common/json_help.c ../common/json_help.h
 	keepalive.c
-	lib_load.h
+	../common/lib_load.h
 	listeners.c
 	logging.c
 	loop.c
@@ -32,14 +32,14 @@ set (MOSQ_SRCS
 	memory_public.c
 	mosquitto.c
 	../include/mosquitto_broker.h mosquitto_broker_internal.h
-	../lib/misc_mosq.c ../lib/misc_mosq.h
+	../common/misc_mosq.c ../common/misc_mosq.h
 	mux.c mux.h mux_epoll.c mux_kqueue.c mux_poll.c
 	net.c
 	../lib/net_mosq_ocsp.c ../lib/net_mosq.c ../lib/net_mosq.h
 	../lib/net_ws.c
 	../lib/packet_datatypes.c
 	../lib/packet_mosq.c ../lib/packet_mosq.h
-	password_mosq.c password_mosq.h
+	../common/password_mosq.c ../common/password_mosq.h
 	persist_read_v234.c persist_read_v5.c persist_read.c
 	persist_write_v5.c persist_write.c
 	persist.h
@@ -69,7 +69,7 @@ set (MOSQ_SRCS
 	../lib/strings_mosq.c
 	subs.c
 	sys_tree.c sys_tree.h
-	../lib/time_mosq.c
+	../common/time_mosq.c ../common/time_mosq.h
 	../lib/tls_mosq.c
 	topic_tok.c
 	../lib/util_mosq.c ../lib/util_topic.c ../lib/util_mosq.h
@@ -225,6 +225,7 @@ target_include_directories(mosquitto PRIVATE
 	"${STDBOOL_H_PATH}"
 	"${STDINT_H_PATH}"
 	"${mosquitto_SOURCE_DIR}"
+	"${mosquitto_SOURCE_DIR}/common"
 	"${mosquitto_SOURCE_DIR}/include"
 	"${mosquitto_SOURCE_DIR}/lib"
 	"${mosquitto_SOURCE_DIR}/src"
diff --git a/src/Makefile b/src/Makefile
index 0b182b67..bbab747a 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -116,7 +116,7 @@ mosquitto.o : mosquitto.c mosquitto_broker_internal.h
 alias_mosq.o : ${R}/lib/alias_mosq.c ${R}/lib/alias_mosq.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
-base64_mosq.o : ${R}/lib/base64_mosq.c ${R}/lib/base64_mosq.h
+base64_mosq.o : ${R}/common/base64_mosq.c ${R}/common/base64_mosq.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
 bridge.o : bridge.c mosquitto_broker_internal.h
@@ -185,7 +185,7 @@ handle_unsubscribe.o : handle_unsubscribe.c mosquitto_broker_internal.h
 http_serv.o : http_serv.c mosquitto_broker_internal.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
-json_help.o : json_help.c json_help.h
+json_help.o : ${R}/common/json_help.c ${R}/common/json_help.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
 keepalive.o : keepalive.c mosquitto_broker_internal.h
@@ -206,7 +206,7 @@ memory_mosq.o : ${R}/lib/memory_mosq.c ${R}/lib/memory_mosq.h
 memory_public.o : memory_public.c mosquitto_broker_internal.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
-misc_mosq.o : ${R}/lib/misc_mosq.c ${R}/lib/misc_mosq.h
+misc_mosq.o : ${R}/common/misc_mosq.c ${R}/common/misc_mosq.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
 mux.o : mux.c mosquitto_broker_internal.h
@@ -233,7 +233,7 @@ net_mosq.o : ${R}/lib/net_mosq.c ${R}/lib/net_mosq.h
 net_ws.o : ${R}/lib/net_ws.c ${R}/lib/net_mosq.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
-password_mosq.o : password_mosq.c password_mosq.h mosquitto_broker_internal.h
+password_mosq.o : ${R}/common/password_mosq.c ${R}/common/password_mosq.h mosquitto_broker_internal.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
 persist_read.o : persist_read.c persist.h mosquitto_broker_internal.h
@@ -374,7 +374,7 @@ subs.o : subs.c mosquitto_broker_internal.h
 sys_tree.o : sys_tree.c mosquitto_broker_internal.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
-time_mosq.o : ${R}/lib/time_mosq.c ${R}/lib/time_mosq.h
+time_mosq.o : ${R}/common/time_mosq.c ${R}/common/time_mosq.h
 	${CROSS_COMPILE}${CC} $(BROKER_CPPFLAGS) $(BROKER_CFLAGS) -c $< -o $@
 
 tls_mosq.o : ${R}/lib/tls_mosq.c
diff --git a/test/unit/Makefile b/test/unit/Makefile
index 39e9b776..a89110fb 100644
--- a/test/unit/Makefile
+++ b/test/unit/Makefile
@@ -3,7 +3,7 @@ include ${R}/config.mk
 
 .PHONY: all check test test-broker test-lib clean coverage
 
-CPPFLAGS:=$(CPPFLAGS) -I${R} -I${R}/include -I${R}/lib -I${R}/src
+CPPFLAGS:=$(CPPFLAGS) -I${R} -I${R}/include -I${R}/lib -I${R}/src -I${R}/common
 ifeq ($(WITH_BUNDLED_DEPS),yes)
         CPPFLAGS:=$(CPPFLAGS) -I${R}/deps
 endif
@@ -138,8 +138,8 @@ memory_mosq.o : ${R}/lib/memory_mosq.c
 memory_public.o : ${R}/src/memory_public.c
 	$(CROSS_COMPILE)$(CC) $(CPPFLAGS) $(CFLAGS) -c -o $@ $^
 
-misc_mosq.o : ${R}/lib/misc_mosq.c
-	$(CROSS_COMPILE)$(CC) $(CPPFLAGS) $(CFLAGS) -c -o $@ $^
+misc_mosq.o : ${R}/common/misc_mosq.c ${R}/common/misc_mosq.h
+	$(CROSS_COMPILE)$(CC) $(CPPFLAGS) $(CFLAGS) -c -o $@ $<
 
 packet_datatypes.o : ${R}/lib/packet_datatypes.c
 	$(CROSS_COMPILE)$(CC) $(CPPFLAGS) $(CFLAGS) -c -o $@ $^