examples/nanocoap_server: add CoAP over TCP support

This changes the Makefile to easily setup lwIP as network stack, while
keeping GNRC as the default.

If lwIP is used on one of the larger boards, the app will be build with
CoAP over TCP support enabled.

examples/nanocoap_server/Makefile

@@ -7,18 +7,25 @@ BOARD ?= native
 # This has to be the absolute path to the RIOT base directory:
 RIOTBASE ?= $(CURDIR)/../..
 
+NETWORK_STACK ?= gnrc
+
 # Include packages that pull up and auto-init the link layer.
 # NOTE: 6LoWPAN will be included if IEEE802.15.4 devices are present
 USEMODULE += netdev_default
-USEMODULE += auto_init_gnrc_netif
-# Specify the mandatory networking modules for IPv6 and UDP
-USEMODULE += gnrc_ipv6_default
 USEMODULE += sock_udp
-# Additional networking modules that can be dropped if not needed
-USEMODULE += gnrc_icmpv6_echo
-
-USEMODULE += nanocoap_sock
-USEMODULE += nanocoap_resources
+USEMODULE += ipv6_addr
+
+ifeq ($(NETWORK_STACK),gnrc)
+  USEMODULE += auto_init_gnrc_netif
+  # Specify the mandatory networking modules for IPv6
+  USEMODULE += gnrc_ipv6_default
+  # Additional networking modules that can be dropped if not needed
+  USEMODULE += gnrc_icmpv6_echo
+endif
+ifeq ($(NETWORK_STACK),lwip)
+  USEMODULE += auto_init_lwip_netif
+  USEMODULE += lwip_ipv6 lwip_ipv6_autoconfig
+endif
 
 USEMODULE += xtimer
 
@@ -43,7 +50,7 @@ ifneq (,$(filter $(BOARD),$(LOW_MEMORY_BOARDS)))
   USEMODULE += prng_minstd
 endif
 
-# Enable fileserver for boards with plenty of memory
+# Enable fileserver and TCP for boards with plenty of memory
 HIGH_MEMORY_BOARDS := native native64 same54-xpro mcb2388
 
 ifneq (,$(filter $(BOARD),$(HIGH_MEMORY_BOARDS)))
@@ -61,6 +68,17 @@ ifneq (,$(filter $(BOARD),$(HIGH_MEMORY_BOARDS)))
   ifneq (,$(filter native native64,$(BOARD)))
     USEMODULE += vfs_auto_format
   endif
+
+  # async TCP is not supported on GNRC yet
+  ifeq ($(NETWORK_STACK),lwip)
+    USEMODULE += nanocoap_server_tcp
+  endif
+endif
+
+# if nanocaop_server_tcp is used: This app makes use of event_thread
+# to run the TCP server
+ifneq (,$(filter nanocoap_server_tcp,$(USEMODULE)))
+  USEMODULE += event_thread
 endif
 
 # Change this to 0 show compiler invocation lines by default:

examples/nanocoap_server/coap_handler.c

@@ -15,8 +15,7 @@
 #include "net/nanocoap_sock.h"
 #include "hashes/sha256.h"
 
-#if MODULE_EVENT_THREAD
-#  include "event.h"
+#if MODULE_NANOCOAP_SERVER_SEPARATE
 #  include "event/thread.h"
 #  include "event/timeout.h"
 #  include "event/callback.h"
@@ -210,8 +209,8 @@ static ssize_t _separate_handler(coap_pkt_t *pkt, uint8_t *buf, size_t len, coap
     if (event_timeout_is_pending(&event_timeout)) {
         if (nanocoap_is_duplicate_in_separate_ctx(&_separate_ctx, pkt, context)) {
             /* no need to check transport: Only UDP can have duplicates */
-            puts("_separate_handler(): duplicate --> ACK");
-            return coap_build_empty_ack(pkt, (void *)buf);
+            puts("_separate_handler(): duplicate");
+            return coap_reply_empty_ack(pkt, buf, len);
         }
         puts("_separate_handler(): response already scheduled");
         return coap_build_reply(pkt, COAP_CODE_SERVICE_UNAVAILABLE, buf, len, 0);
@@ -229,12 +228,7 @@ static ssize_t _separate_handler(coap_pkt_t *pkt, uint8_t *buf, size_t len, coap
                               &event_timed.super);
     event_timeout_set(&event_timeout, 1 * MS_PER_SEC);
 
-    if (coap_get_transport(pkt) == COAP_TRANSPORT_TCP) {
-        /* no empty ACK in TCP needed */
-        return 0;
-    }
-
-    return coap_build_empty_ack(pkt, (void *)buf);
+    return coap_reply_empty_ack(pkt, buf, len);
 }
 
 NANOCOAP_RESOURCE(separate) {

examples/nanocoap_server/main.c

@@ -22,11 +22,19 @@
 #include "net/nanocoap_sock.h"
 #include "xtimer.h"
 
+#if MODULE_NANOCOAP_SERVER_TCP
+#  include "event/thread.h"
+#endif
+
 #define COAP_INBUF_SIZE (256U)
 
 #define MAIN_QUEUE_SIZE     (8)
 static msg_t _main_msg_queue[MAIN_QUEUE_SIZE];
 
+#if MODULE_NANOCOAP_SERVER_TCP
+static nanocoap_tcp_server_ctx_t tcp_ctx;
+#endif
+
 int main(void)
 {
     puts("RIOT nanocoap example application");
@@ -42,10 +50,16 @@ int main(void)
     netifs_print_ipv6("\", \"");
     puts("\"]}");
 
+#if MODULE_NANOCOAP_SERVER_TCP
+    nanocoap_server_tcp(&tcp_ctx, EVENT_PRIO_MEDIUM, NULL);
+#endif
+
+#if MODULE_NANOCOAP_UDP
     /* initialize nanocoap server instance */
     uint8_t buf[COAP_INBUF_SIZE];
     sock_udp_ep_t local = { .port=COAP_PORT, .family=AF_INET6 };
-    nanocoap_server(&local, buf, sizeof(buf));
+    nanocoap_server_udp(&local, buf, sizeof(buf));
+#endif
 
     /* should be never reached */
     return 0;