gnrc_netif: replace GNRC_NETIF_SINGLE with gnrc_netif_single pseudo-module

examples/emcute_mqttsn/Makefile

@@ -22,15 +22,14 @@ USEMODULE += shell_commands
 USEMODULE += ps
 # For testing we also include the ping6 command and some stats
 USEMODULE += gnrc_icmpv6_echo
+# Optimize network stack to for use with a single network interface
+USEMODULE += gnrc_netif_single
 
 # Allow for env-var-based override of the nodes name (EMCUTE_ID)
 ifneq (,$(EMCUTE_ID))
   CFLAGS += -DEMCUTE_ID=\"$(EMCUTE_ID)\"
 endif
 
-# Optimize network stack to for use with a single network interface
-CFLAGS += -DGNRC_NETIF_SINGLE
-
 # Comment this out to disable code in RIOT that does safety checking
 # which is not needed in a production environment but helps in the
 # development process:

examples/gnrc_minimal/Makefile

@@ -16,6 +16,9 @@ DEVELHELP ?= 0
 # NOTE: 6LoWPAN will be included if IEEE802.15.4 devices are present
 USEMODULE += gnrc_netdev_default
 USEMODULE += auto_init_gnrc_netif
+# Enable single interface optimization.
+# Remove this if more than one interface is present
+USEMODULE += gnrc_netif_single
 # Specify the minimum networking modules for IPv6
 USEMODULE += gnrc_ipv6
 # Additional networking modules that can be dropped if not needed
@@ -32,10 +35,6 @@ CFLAGS += -DCONFIG_GNRC_NETIF_IPV6_ADDRS_NUMOF=2 \
           -DGNRC_NETIF_IPV6_GROUPS_NUMOF=2 -DCONFIG_GNRC_IPV6_NIB_NUMOF=1 \
           -DCONFIG_GNRC_IPV6_NIB_OFFL_NUMOF=1 # be able to configure at least one route
 
-# Enable single interface optimization. Set to 0 if more than one interface is
-# present
-CFLAGS += -DGNRC_NETIF_SINGLE=1
-
 # Change this to 0 show compiler invocation lines by default:
 QUIET ?= 1
 

makefiles/pseudomodules.inc.mk

@@ -41,6 +41,7 @@ PSEUDOMODULES += gnrc_pktbuf_cmd
 PSEUDOMODULES += gnrc_netif_6lo
 PSEUDOMODULES += gnrc_netif_ipv6
 PSEUDOMODULES += gnrc_netif_mac
+PSEUDOMODULES += gnrc_netif_single
 PSEUDOMODULES += gnrc_netif_cmd_%
 PSEUDOMODULES += gnrc_netif_dedup
 PSEUDOMODULES += gnrc_nettype_%

sys/include/net/gnrc/netif.h

@@ -14,6 +14,11 @@
  * Network interfaces in the context of GNRC are threads for protocols that are
  * below the network layer.
  *
+ * ## Single interface optimizations
+ *
+ * If you only have one network interface on the board, you can select the
+ * `gnrc_netif_single` pseudo-module to enable further optimisations.
+ *
  * @{
  *
  * @file
@@ -330,7 +335,7 @@ unsigned gnrc_netif_numof(void);
  */
 static inline bool gnrc_netif_highlander(void)
 {
-    return IS_ACTIVE(GNRC_NETIF_SINGLE);
+    return IS_USED(MODULE_GNRC_NETIF_SINGLE);
 }
 
 /**

sys/include/net/gnrc/netif/conf.h

@@ -31,18 +31,6 @@
 extern "C" {
 #endif
 
-/**
- * @brief   Single interface optimizations
- *
- *          Define to 1 to allow GNRC optimizations when only one interface
- *          is available.
- *
- * @note    This MUST NOT be enabled if there's more than one interface.
- */
-#if DOXYGEN
-#define GNRC_NETIF_SINGLE
-#endif
-
 /**
  * @brief   Default priority for network interface threads
  */

tests/emcute/Makefile

@@ -17,6 +17,8 @@ endif
 USEMODULE += auto_init_gnrc_netif
 USEMODULE += gnrc_ipv6_default
 USEMODULE += gnrc_sock_udp
+USEMODULE += gnrc_netif_single          # Only one interface used and it makes
+                                        # shell commands easier
 USEMODULE += emcute
 USEMODULE += od
 USEMODULE += shell
@@ -25,8 +27,6 @@ USEMODULE += sock_util
 
 CFLAGS += -DEMCUTE_TOPIC_MAXLEN="249"   # 256 - 7
 CFLAGS += -DSTDIO_UART_RX_BUFSIZE="512" # Adapt to SHELL_BUFSIZE in app
-CFLAGS += -DGNRC_NETIF_SINGLE           # Only one interface used and it makes
-                                        # shell commands easier
 
 # The test requires some setup and to be run as root
 # So it cannot currently be run

tests/gnrc_sock_dns/Makefile

@@ -4,13 +4,12 @@ RIOTBASE ?= $(CURDIR)/../..
 
 export TAP ?= tap0
 
-CFLAGS += -DGNRC_NETIF_SINGLE           # Only one interface used and it makes
-                                        # shell commands easier
-
 USEMODULE += sock_dns
 USEMODULE += gnrc_sock_udp
 USEMODULE += gnrc_ipv6_default
 USEMODULE += gnrc_ipv6_nib_dns
+USEMODULE += gnrc_netif_single          # Only one interface used and it makes
+                                        # shell commands easier
 # use Ethernet as link-layer protocol
 ifeq (native,$(BOARD))
   TERMFLAGS ?= $(TAP)

tests/gnrc_tcp/Makefile

@@ -13,8 +13,6 @@ TIMEOUT_US ?= 3000000
 TEST_ON_CI_BLACKLIST += all
 
 CFLAGS += -DSHELL_NO_ECHO
-CFLAGS += -DGNRC_NETIF_SINGLE           # Only one interface used and it makes
-                                        # shell commands easier
 
 ifeq (native,$(BOARD))
   TERMFLAGS ?= $(TAP)
@@ -30,6 +28,8 @@ USEMODULE += auto_init_gnrc_netif
 USEMODULE += gnrc_ipv6_default
 USEMODULE += gnrc_tcp
 USEMODULE += gnrc_pktbuf_cmd
+USEMODULE += gnrc_netif_single          # Only one interface used and it makes
+                                        # shell commands easier
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += od