zephyr: Examples support

New examples/zephyr directory that contains a sample coap-client.
Building the coap-client assumes that the zephyrproject has already been
installed and set up (default directory ~/zephyrproject).

BUILDING

@@ -142,6 +142,14 @@ Contiki-NG
 Executable is ./server.native. See examples/contiki/README for further
 information.
 
+Zephyr
+======
+
+ cd examples/zephyr
+ make
+
+See examples/zephyr/README for further information.
+
 Windows
 =======
 

CMakeLists.txt

@@ -25,15 +25,16 @@ option(
   BUILD_SHARED_LIBS
   "Build shared libs"
   OFF)
-else()
+else() # ! ZEPHYR_BASE
   # provided by the zephyr build system
-endif()
+endif() # ! ZEPHYR_BASE
 
 #
 # global compiler options
 # (need to do it before add_library())
 #
 
+if(NOT ZEPHYR_BASE)
 add_compile_options(
   $<$<OR:$<CXX_COMPILER_ID:GNU>,$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>>:-pedantic>
   $<$<OR:$<CXX_COMPILER_ID:GNU>,$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>>:-Wall>
@@ -51,6 +52,9 @@ add_compile_options(
   $<$<OR:$<CXX_COMPILER_ID:GNU>,$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>>:-Wswitch-enum>
   $<$<OR:$<CXX_COMPILER_ID:GNU>,$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>>:-Wunused>
   $<$<OR:$<CXX_COMPILER_ID:GNU>,$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>>:-Wwrite-strings>)
+else() # ! ZEPHYR_BASE
+  # provided by the zephyr build system
+endif() # ! ZEPHYR_BASE
 
 if(MINGW)
 add_compile_options(
@@ -76,7 +80,9 @@ endif()
 #
 
 add_library(${COAP_LIBRARY_NAME})
-set_property(TARGET ${COAP_LIBRARY_NAME} PROPERTY C_STANDARD 99)
+if(NOT ZEPHYR_BASE)
+#  set_property(TARGET ${COAP_LIBRARY_NAME} PROPERTY C_STANDARD 99)
+endif() # ! ZEPHYR_BASE
 if(${CMAKE_VERSION} VERSION_GREATER "3.20.0")
   cmake_policy(SET CMP0115 OLD) # Supresses libcoap configuration warning
 endif()
@@ -392,7 +398,6 @@ else()
   message(STATUS "compiling without Q-Block (RFC9177) support")
 endif()
 
-
 if(${WITH_OBSERVE_PERSIST})
   set(COAP_WITH_OBSERVE_PERSIST "1")
   message(STATUS "compiling with observe persistence support")
@@ -413,17 +418,17 @@ else()
   message(STATUS "compiling without epoll support")
 endif()
 
-if(ENABLE_THREAD_SAFE)
+if(${ENABLE_THREAD_SAFE})
   set(COAP_THREAD_SAFE "${ENABLE_THREAD_SAFE}")
   message(STATUS "compiling with thread safe support")
 endif()
 
-if(ENABLE_THREAD_RECURSIVE_LOCK_CHECK)
+if(${ENABLE_THREAD_RECURSIVE_LOCK_CHECK})
   set(COAP_THREAD_RECURSIVE_CHECK "${ENABLE_THREAD_RECURSIVE_LOCK_CHECK}")
   message(STATUS "compiling with thread recursive lock detection support")
 endif()
 
-if(ENABLE_SMALL_STACK)
+if(${ENABLE_SMALL_STACK})
   set(COAP_CONSTRAINED_STACK "${ENABLE_SMALL_STACK}")
   message(STATUS "compiling with small stack support")
 endif()
@@ -646,6 +651,7 @@ if(WITH_WOLFSSL)
 endif()
 
 execute_process(COMMAND git describe --tags --dirty --always
+		WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}
                 RESULT_VARIABLE USING_GIT
                 OUTPUT_VARIABLE LIBCOAP_PACKAGE_BUILD
                 OUTPUT_STRIP_TRAILING_WHITESPACE
@@ -847,7 +853,7 @@ if(ZEPHYR_BASE)
 target_compile_options(
   ${COAP_LIBRARY_NAME}
   PUBLIC -DMBEDTLS_CONFIG_FILE="${CONFIG_MBEDTLS_CFG_FILE}" -I${ZEPHYR_MBEDTLS_CMAKE_DIR}/configs)
-endif()
+endif() # ! ZEPHYR_BASE
 
 add_library(
   ${PROJECT_NAME}::${COAP_LIBRARY_NAME}
@@ -984,7 +990,7 @@ install(
   DESTINATION ${LIBCOAP_CONFIG_INSTALL_DIR}
   NAMESPACE ${PROJECT_NAME}::
   COMPONENT dev)
-endif()
+endif() # ! ZEPHYR_BASE
 
 configure_package_config_file(
   cmake/Config.cmake.in

examples/zephyr/.gitignore

@@ -0,0 +1,2 @@
+# never objects, and not the resulting binary
+coap-client

examples/zephyr/Makefile

@@ -0,0 +1,16 @@
+ZEPHYR_PROJECT?=~/zephyrproject
+
+all: coap-client
+
+coap-client: client-src/src/main.c client-src/*
+	LIBCOAP_DIR=`pwd`/../.. ;\
+	(. $(ZEPHYR_PROJECT)/.venv/bin/activate ;\
+	cd $(ZEPHYR_PROJECT)/zephyr ;\
+	west build -p always -b native_sim \
+		$${LIBCOAP_DIR}/examples/zephyr/client-src -- \
+		-DCONF_FILE=prj.conf \
+		-DEXTRA_ZEPHYR_MODULES=$${LIBCOAP_DIR} \
+		-DEXTRA_CONF_FILE=$${LIBCOAP_DIR}/zephyr/libcoap-mbedtls.conf \
+		--fresh ;\
+	deactivate) ;\
+	cp -f $(ZEPHYR_PROJECT)/zephyr/build/zephyr/zephyr.exe coap-client

examples/zephyr/README

@@ -0,0 +1,12 @@
+Example of libcoap running in Zephyr
+====================================
+
+The Zephyr project environment needs to be pre-installed.  By default, the
+libcoap Makefile assumes that this is located at ~/zephyrproject .
+
+To build the coap-client example, do
+
+    $ make
+
+The executable gets built in ~/zephyrproject/zephyr/build/zephyr/zephyr.exe
+which is then copied to coap-client .

examples/zephyr/client-src/CMakeLists.txt

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(coap_client)
+
+target_sources(app PRIVATE src/main.c)
+
+include(${ZEPHYR_BASE}/samples/net/common/common.cmake)

examples/zephyr/client-src/Kconfig

@@ -0,0 +1,33 @@
+# Private config options for coap-client sample app
+
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+mainmenu "Networking coap-client sample application"
+
+config LIBCOAP_TARGET_DOMAIN_URI
+    string "Target Uri"
+    default "coaps://libcoap.net"
+    help
+        Target uri for the example to use. Use coaps:// prefix for encrypted traffic
+        using Pre-Shared Key (PSK) or Public Key Infrastructure (PKI).
+
+if MBEDTLS
+config LIBCOAP_PSK_KEY
+    string "Preshared Key (PSK) to used in the connection to the CoAP server"
+    default "secretPSK"
+    help
+        The Preshared Key to use to encrypt the communicatons. The same key must be
+        used at both ends of the CoAP connection, and the CoaP client must request
+        an URI prefixed with coaps:// instead of coap:// for DTLS to be used.
+
+config LIBCOAP_PSK_IDENTITY
+    string "PSK Client identity (username)"
+    default "user"
+    help
+        The identity (or username) to use to identify to the CoAP server which
+        PSK key to use.
+
+endif # MBEDTLS
+
+source "Kconfig.zephyr"

examples/zephyr/client-src/prj.conf

@@ -0,0 +1,44 @@
+CONFIG_NETWORKING=y
+CONFIG_NET_UDP=y
+CONFIG_NET_TCP=y
+CONFIG_NET_IPV6=y
+CONFIG_NET_IPV4=y
+#CONFIG_NET_DHCPV4=y
+
+CONFIG_ENTROPY_GENERATOR=y
+CONFIG_TEST_RANDOM_GENERATOR=y
+CONFIG_INIT_STACKS=y
+
+CONFIG_NET_LOG=y
+CONFIG_LOG=y
+
+CONFIG_NET_STATISTICS=y
+
+CONFIG_NET_PKT_RX_COUNT=32
+CONFIG_NET_PKT_TX_COUNT=32
+CONFIG_NET_BUF_RX_COUNT=32
+CONFIG_NET_BUF_TX_COUNT=32
+
+CONFIG_NET_IF_UNICAST_IPV6_ADDR_COUNT=3
+CONFIG_NET_IF_MCAST_IPV6_ADDR_COUNT=4
+CONFIG_NET_MAX_CONTEXTS=10
+
+CONFIG_NET_SHELL=y
+
+CONFIG_NET_CONFIG_SETTINGS=y
+CONFIG_NET_CONFIG_NEED_IPV6=y
+CONFIG_NET_CONFIG_NEED_IPV4=y
+CONFIG_NET_CONFIG_MY_IPV6_ADDR="2001:db8::1"
+CONFIG_NET_CONFIG_PEER_IPV6_ADDR="2001:db8::2"
+CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.0.2.1"
+CONFIG_NET_CONFIG_PEER_IPV4_ADDR="192.0.2.2"
+
+CONFIG_NET_L2_ETHERNET=y
+
+CONFIG_ETH_NATIVE_POSIX=y
+CONFIG_ETH_NATIVE_POSIX_RANDOM_MAC=y
+#CONFIG_ETH_NATIVE_POSIX_MAC_ADDR="00:00:5e:00:53:2a"
+
+CONFIG_LIBCOAP=y
+
+CONFIG_HEAP_MEM_POOL_SIZE=16384