sys/net/gnrc/netif: allow checking if a netdev is legacy or new API

A if `netdev_driver_t::confirm_send()` is provided, it provides the
new netdev API. However, detecting the API at runtime and handling
both API styles comes at a cost. This can be optimized in case only
new or only old style netdevs are in use.

To do so, this adds the pseudo modules `netdev_legacy_api` and
`netdev_new_api`. As right now no netdev actually implements the new
API, all netdevs pull in `netdev_legacy_api`. If `netdev_legacy_api` is
in used but `netdev_new_api` is not, we can safely assume at compile
time that only legacy netdevs are in use. Similar, if only
`netdev_new_api` is used, only support for the new API is needed. Only
when both are in use, run time checks are needed.

This provides two helper function to check for a netif if the
corresponding netdev implements the old or the new API. (With one
being the inverse of the other.) They are suitable for constant folding
when only new or only legacy devices are in use. Consequently, dead
branches should be eliminated by the optimizer.

cpu/esp_common/Makefile.dep

@@ -97,6 +97,7 @@ ifneq (,$(filter esp_wifi,$(USEMODULE)))
 endif
 
 ifneq (,$(filter esp_wifi_any,$(USEMODULE)))
+  USEMODULE += netdev_legacy_api
   USEMODULE += netopt
   USEMODULE += ztimer_msec
 endif

cpu/sam0_common/Makefile.dep

@@ -14,9 +14,10 @@ endif
 USEMODULE += sam0_common_periph
 
 ifneq (,$(filter sam0_eth,$(USEMODULE)))
-  USEMODULE += netdev_eth
-  USEMODULE += netopt
   USEMODULE += iolist
+  USEMODULE += netdev_eth
+  USEMODULE += netdev_legacy_api
+  USEMODULE += netopt
   FEATURES_REQUIRED += periph_eth
 endif
 include $(RIOTCPU)/cortexm_common/Makefile.dep

cpu/stm32/Makefile.dep

@@ -22,8 +22,9 @@ endif
 
 ifneq (,$(filter stm32_eth,$(USEMODULE)))
   FEATURES_REQUIRED += periph_eth
-  USEMODULE += netdev_eth
   USEMODULE += iolist
+  USEMODULE += netdev_eth
+  USEMODULE += netdev_legacy_api
   USEMODULE += ztimer
   USEMODULE += ztimer_msec
 

drivers/Makefile.dep

@@ -237,7 +237,7 @@ ifneq (,$(filter periph_timer_periodic,$(USEMODULE)))
   FEATURES_REQUIRED += periph_timer
 endif
 
-ifneq (,$(filter-out netdev_default, $(filter netdev_%,$(USEMODULE))))
+ifneq (,$(filter-out netdev_default netdev_new_api netdev_legacy_api, $(filter netdev_%,$(USEMODULE))))
   USEMODULE += netdev
   # Don't register netdevs if there is only a single one of them
   ifeq (,$(filter gnrc_netif_single,$(USEMODULE)))

drivers/at86rf215/Kconfig

@@ -16,6 +16,7 @@ menuconfig MODULE_AT86RF215
     depends on HAS_PERIPH_SPI
     select MODULE_NETDEV
     select MODULE_NETDEV_IEEE802154
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_SPI

drivers/at86rf215/Makefile.dep

@@ -33,3 +33,4 @@ endif
 USEMODULE += xtimer
 USEMODULE += ieee802154
 USEMODULE += netdev_ieee802154
+USEMODULE += netdev_legacy_api

drivers/at86rf2xx/Kconfig

@@ -10,10 +10,11 @@ menuconfig MODULE_AT86RF2XX
     prompt "AT86RF2xx series radios" if !(MODULE_NETDEV_DEFAULT && HAVE_AT86RF2XX)
     default (MODULE_NETDEV_DEFAULT && HAVE_AT86RF2XX)
     depends on TEST_KCONFIG
-    select MODULE_XTIMER
+    select MODULE_IEEE802154
     select MODULE_NETDEV
     select MODULE_NETDEV_IEEE802154
-    select MODULE_IEEE802154
+    select MODULE_NETDEV_LEGACY_API
+    select MODULE_XTIMER
 
 if MODULE_AT86RF2XX
 

drivers/at86rf2xx/Makefile.dep

@@ -4,6 +4,7 @@ DEFAULT_MODULE += netdev_ieee802154_oqpsk
 USEMODULE += xtimer
 USEMODULE += ieee802154
 USEMODULE += netdev_ieee802154
+USEMODULE += netdev_legacy_api
 
 # only needed for SPI based variants
 ifeq (,$(filter at86rfa1 at86rfr2,$(USEMODULE)))

drivers/atwinc15x0/Makefile.dep

@@ -1,5 +1,6 @@
 USEMODULE += netdev_eth
 USEMODULE += ztimer_msec
+USEMODULE += netdev_legacy_api
 USEPKG += driver_atwinc15x0
 FEATURES_REQUIRED += periph_gpio
 FEATURES_REQUIRED += periph_gpio_irq

drivers/cc110x/Makefile.dep

@@ -1,6 +1,7 @@
 USEMODULE += cc1xxx_common
 USEMODULE += luid
 USEMODULE += xtimer
+USEMODULE += netdev_legacy_api
 FEATURES_REQUIRED += periph_gpio
 FEATURES_REQUIRED += periph_gpio_irq
 FEATURES_REQUIRED += periph_spi

drivers/cc2420/Kconfig

@@ -11,13 +11,14 @@ config MODULE_CC2420
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_SPI
+    select MODULE_IEEE802154
+    select MODULE_NETDEV
+    select MODULE_NETDEV_IEEE802154
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_SPI
     select MODULE_XTIMER
-    select MODULE_IEEE802154
-    select MODULE_NETDEV
-    select MODULE_NETDEV_IEEE802154
 
 config HAVE_CC2420
     bool

drivers/cc2420/Makefile.dep

@@ -1,6 +1,7 @@
 USEMODULE += xtimer
 USEMODULE += ieee802154
 USEMODULE += netdev_ieee802154
+USEMODULE += netdev_legacy_api
 FEATURES_REQUIRED += periph_gpio
 FEATURES_REQUIRED += periph_gpio_irq
 FEATURES_REQUIRED += periph_spi

drivers/dose/Kconfig

@@ -28,15 +28,16 @@ menuconfig MODULE_DOSE
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_UART
+    select MODULE_CHUNKED_RINGBUFFER
+    select MODULE_EUI_PROVIDER
+    select MODULE_IOLIST
+    select MODULE_NETDEV_ETH
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_UART
     select MODULE_PERIPH_UART_COLLISION if HAS_PERIPH_UART_COLLISION
     select MODULE_PERIPH_UART_RXSTART_IRQ if HAS_PERIPH_UART_RXSTART_IRQ
-    select MODULE_CHUNKED_RINGBUFFER
-    select MODULE_EUI_PROVIDER
-    select MODULE_IOLIST
-    select MODULE_NETDEV_ETH
     select MODULE_RANDOM
     select MODULE_ZTIMER
     select ZTIMER_USEC

drivers/dose/Makefile.dep

@@ -11,5 +11,6 @@ USEMODULE += chunked_ringbuffer
 USEMODULE += eui_provider
 USEMODULE += iolist
 USEMODULE += netdev_eth
+USEMODULE += netdev_legacy_api
 USEMODULE += random
 USEMODULE += ztimer_usec

drivers/enc28j60/Kconfig

@@ -11,11 +11,12 @@ config MODULE_ENC28J60
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_SPI
+    select MODULE_NETDEV_ETH
+    select MODULE_NETDEV_LEGACY_API
+    select MODULE_PERIPH_EUI_PROVIDER
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_SPI
-    select MODULE_PERIPH_EUI_PROVIDER
-    select MODULE_NETDEV_ETH
     select MODULE_XTIMER
 
 config HAVE_ENC28J60

drivers/enc28j60/Makefile.dep

@@ -4,4 +4,5 @@ FEATURES_REQUIRED += periph_spi
 
 USEMODULE += eui_provider
 USEMODULE += netdev_eth
+USEMODULE += netdev_legacy_api
 USEMODULE += xtimer

drivers/encx24j600/Kconfig

@@ -11,10 +11,11 @@ config MODULE_ENCX24J600
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_SPI
+    select MODULE_NETDEV_ETH
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_SPI
-    select MODULE_NETDEV_ETH
     select MODULE_XTIMER
 
 config HAVE_ENCX24J600

drivers/encx24j600/Makefile.dep

@@ -1,4 +1,5 @@
 FEATURES_REQUIRED += periph_gpio_irq
 FEATURES_REQUIRED += periph_spi
 USEMODULE += netdev_eth
+USEMODULE += netdev_legacy_api
 USEMODULE += xtimer

drivers/ethos/Kconfig

@@ -9,9 +9,10 @@ config MODULE_ETHOS
     bool "Ethernet-over-serial (ETHOS)"
     depends on TEST_KCONFIG
     depends on HAS_PERIPH_UART
-    select MODULE_PERIPH_UART
     select MODULE_IOLIST
     select MODULE_NETDEV_ETH
+    select MODULE_NETDEV_LEGACY_API
+    select MODULE_PERIPH_UART
     select MODULE_RANDOM
     select MODULE_TSRB
 

drivers/ethos/Makefile.dep

@@ -1,6 +1,7 @@
 FEATURES_REQUIRED += periph_uart
 USEMODULE += iolist
 USEMODULE += netdev_eth
+USEMODULE += netdev_legacy_api
 USEMODULE += random
 USEMODULE += tsrb
 

drivers/kw2xrf/Kconfig

@@ -13,16 +13,15 @@ menuconfig MODULE_KW2XRF
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_SPI
+    select MODULE_CORE_THREAD_FLAGS
+    select MODULE_IEEE802154
+    select MODULE_LUID
+    select MODULE_NETDEV
+    select MODULE_NETDEV_IEEE802154
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_SPI
-    select MODULE_LUID
-    select MODULE_IEEE802154
-    select MODULE_NETDEV
-    select MODULE_NETDEV_IEEE802154
-    select MODULE_CORE_THREAD_FLAGS
-    select MODULE_IOLIST
-    select HAVE_BHP_IRQ_HANDLER
 
 config MODULE_KW2XRF_TESTMODE
     bool "Test mode"

drivers/mrf24j40/Kconfig

@@ -13,13 +13,14 @@ menuconfig MODULE_MRF24J40
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_SPI
+    select MODULE_IEEE802154
+    select MODULE_NETDEV
+    select MODULE_NETDEV_IEEE802154
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_SPI
     select MODULE_XTIMER
-    select MODULE_IEEE802154
-    select MODULE_NETDEV
-    select MODULE_NETDEV_IEEE802154
 
 if MODULE_MRF24J40
 

drivers/mrf24j40/Makefile.dep

@@ -1,6 +1,7 @@
-USEMODULE += xtimer
 USEMODULE += ieee802154
 USEMODULE += netdev_ieee802154
+USEMODULE += netdev_legacy_api
+USEMODULE += xtimer
 FEATURES_REQUIRED += periph_gpio
 FEATURES_REQUIRED += periph_gpio_irq
 FEATURES_REQUIRED += periph_spi

drivers/netdev/Kconfig

@@ -82,6 +82,23 @@ config MODULE_NETDEV_REGISTER
 
 endif # MODULE_NETDEV
 
+# This does not depend on MODULE_NETDEV, as it is merely a flag to say if a
+# given network driver is used via the netdev API, it provides the new netdev
+# API. However, the driver may also provide a API other than netdev that might
+# be used directly.
+config MODULE_NETDEV_NEW_API
+    bool
+    help
+        Support for new API (non-blocking send). With this, netdev
+        drivers implementing `netdev_driver_t::confirm_send()` can be used.
+
+# Comment above MODULE_NETDEV_NEW_API also applies here.
+config MODULE_NETDEV_LEGACY_API
+    bool
+    help
+        Support for legacy netdev API (blocking send). With this, netdev drivers
+        **NOT** implementing `netdev_driver_t::confirm_send()` can be used.
+
 endif # TEST_KCONFIG
 
 config HAVE_NON_NETDEV_INTERFACE

drivers/netdev_ieee802154_submac/Kconfig

@@ -10,9 +10,10 @@ config MODULE_NETDEV_IEEE802154_SUBMAC
     depends on TEST_KCONFIG
     depends on MODULE_NETDEV
     default y if HAVE_IEEE802154_RADIO_HAL_INTERFACE
-    select MODULE_NETDEV_IEEE802154
     select MODULE_IEEE802154
     select MODULE_IEEE802154_SUBMAC
+    select MODULE_NETDEV_IEEE802154
+    select MODULE_NETDEV_LEGACY_API
     help
       This module implements the netdev API on top of the IEEE 802.15.4 radio
       HAL.

drivers/nrf24l01p_ng/Makefile.dep

@@ -1,4 +1,5 @@
 USEMODULE += luid
+USEMODULE += netdev_legacy_api
 USEMODULE += netif
 USEMODULE += xtimer
 ifneq (,$(filter gnrc_ipv6,$(USEMODULE)))

drivers/rn2xx3/Kconfig

@@ -27,9 +27,10 @@ config MODULE_RN2XX3
     bool
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_UART
+    select MODULE_FMT
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_UART
-    select MODULE_FMT
     select MODULE_ZTIMER
     select MODULE_ZTIMER_MSEC
 

drivers/rn2xx3/Makefile.dep

@@ -1,5 +1,6 @@
 FEATURES_REQUIRED += periph_gpio
 FEATURES_REQUIRED += periph_uart
+USEMODULE += fmt
+USEMODULE += netdev_legacy_api
 USEMODULE += ztimer
 USEMODULE += ztimer_msec
-USEMODULE += fmt

drivers/slipdev/Kconfig

@@ -10,8 +10,9 @@ menuconfig MODULE_SLIPDEV
     bool "SLIP over UART network device"
     depends on HAS_PERIPH_UART
     depends on TEST_KCONFIG
-    select MODULE_TSRB
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_UART
+    select MODULE_TSRB
 
 menuconfig KCONFIG_USEMODULE_SLIPDEV
     bool "Configure SLIPDEV driver"

drivers/slipdev/Makefile.dep

@@ -1,6 +1,7 @@
-USEMODULE += tsrb
 USEMODULE += eui_provider
+USEMODULE += netdev_legacy_api
 USEMODULE += netdev_register
+USEMODULE += tsrb
 FEATURES_REQUIRED += periph_uart
 
 ifneq (,$(filter slipdev_stdio,$(USEMODULE)))

drivers/sx126x/Kconfig

@@ -13,10 +13,11 @@ menuconfig MODULE_SX126X
     depends on HAS_PERIPH_SPI
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
+    select MODULE_IOLIST
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_SPI
     select PACKAGE_DRIVER_SX126X
-    select MODULE_IOLIST
 
 choice
     bool "Radio variant"

drivers/sx126x/Makefile.dep

@@ -1,3 +1,4 @@
 USEMODULE += iolist
+USEMODULE += netdev_legacy_api
 USEPKG += driver_sx126x
 FEATURES_REQUIRED += periph_gpio_irq

drivers/sx127x/Kconfig

@@ -14,14 +14,15 @@ menuconfig MODULE_SX127X
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_SPI
     depends on HAS_PERIPH_TIMER
-    select MODULE_PERIPH_GPIO
-    select MODULE_PERIPH_GPIO_IRQ
-    select MODULE_PERIPH_SPI_GPIO_MODE if HAS_PERIPH_SPI_GPIO_MODE
-    select MODULE_PERIPH_SPI
-    select MODULE_ZTIMER
-    select MODULE_ZTIMER_MSEC
     select MODULE_IOLIST
     select MODULE_LORA
+    select MODULE_NETDEV_LEGACY_API
+    select MODULE_PERIPH_GPIO
+    select MODULE_PERIPH_GPIO_IRQ
+    select MODULE_PERIPH_SPI
+    select MODULE_PERIPH_SPI_GPIO_MODE if HAS_PERIPH_SPI_GPIO_MODE
+    select MODULE_ZTIMER
+    select MODULE_ZTIMER_MSEC
     help
         Only LoRa long range modem is supported at the moment.
 

drivers/sx127x/Makefile.dep

@@ -3,6 +3,7 @@ FEATURES_REQUIRED += periph_gpio_irq
 FEATURES_REQUIRED += periph_spi
 FEATURES_OPTIONAL += periph_spi_gpio_mode
 USEMODULE += iolist
+USEMODULE += netdev_legacy_api
 USEMODULE += ztimer_msec
 
 USEMODULE += lora

drivers/sx1280/Makefile.dep

@@ -1,2 +1,3 @@
 USEPKG += lorabasics
 USEMODULE += lorabasics_sx1280_driver
+USEMODULE += netdev_legacy_api

drivers/w5100/Kconfig

@@ -11,11 +11,12 @@ config MODULE_W5100
     depends on HAS_PERIPH_GPIO
     depends on HAS_PERIPH_GPIO_IRQ
     depends on HAS_PERIPH_SPI
+    select MODULE_LUID
+    select MODULE_NETDEV_ETH
+    select MODULE_NETDEV_LEGACY_API
     select MODULE_PERIPH_GPIO
     select MODULE_PERIPH_GPIO_IRQ
     select MODULE_PERIPH_SPI
-    select MODULE_NETDEV_ETH
-    select MODULE_LUID
 
 config HAVE_W5100
     bool

drivers/w5100/Makefile.dep

@@ -1,4 +1,5 @@
 FEATURES_REQUIRED += periph_gpio_irq
 FEATURES_REQUIRED += periph_spi
-USEMODULE += netdev_eth
 USEMODULE += luid
+USEMODULE += netdev_eth
+USEMODULE += netdev_legacy_api

drivers/xbee/Makefile.dep

@@ -1,5 +1,6 @@
 FEATURES_REQUIRED += periph_uart
 FEATURES_REQUIRED += periph_gpio
 USEMODULE += ieee802154
+USEMODULE += netdev_legacy_api
 USEMODULE += ztimer
 USEMODULE += ztimer_msec

makefiles/pseudomodules.inc.mk

@@ -156,6 +156,8 @@ PSEUDOMODULES += netdev_ieee802154_rx_timestamp
 PSEUDOMODULES += netdev_ieee802154
 PSEUDOMODULES += netdev_eth
 PSEUDOMODULES += netdev_layer
+PSEUDOMODULES += netdev_legacy_api
+PSEUDOMODULES += netdev_new_api
 PSEUDOMODULES += netdev_register
 PSEUDOMODULES += netstats
 PSEUDOMODULES += netstats_l2

sys/Makefile.dep

@@ -173,6 +173,7 @@ endif
 
 ifneq (,$(filter netdev_ieee802154_submac,$(USEMODULE)))
   USEMODULE += netdev_ieee802154
+  USEMODULE += netdev_legacy_api
   USEMODULE += ieee802154
   USEMODULE += ieee802154_submac
 endif

sys/include/net/gnrc/netif.h

@@ -187,6 +187,55 @@ typedef struct {
     kernel_pid_t pid;                       /**< PID of the network interface's thread */
 } gnrc_netif_t;
 
+/**
+ * @brief   Check if the device belonging to the given netif uses the legacy
+ *          netdev API
+ *
+ * Check @ref netdev_driver_t::confirm_send for info about the old and new
+ * netdev API.
+ *
+ * netdevs using the legacy API have to depend on the (pseudo-)module
+ * netdev_legaqcy_api, netdevs using the new API have to depend on the
+ * (pseudo-)module netdev_new_api. If only one of the pseudo modules is used,
+ * this function can be constant folded. For boards mixing legacy and new API
+ * netdevs, this will check the flavor at runtime.
+ *
+ * @see netdev_driver_t::confirm_send
+ */
+static inline bool gnrc_netif_netdev_legacy_api(gnrc_netif_t *netif)
+{
+    if (!IS_USED(MODULE_NETDEV_NEW_API) && !IS_USED(MODULE_NETDEV_LEGACY_API)) {
+        /* this should only happen for external netdevs or when no netdev is
+         * used (e.g. examples/gcoap can be used without any netdev, as still
+         * CoAP requests to ::1 can be send */
+        return true;
+    }
+
+    if (!IS_USED(MODULE_NETDEV_NEW_API)) {
+        return true;
+    }
+
+    if (!IS_USED(MODULE_NETDEV_LEGACY_API)) {
+        return false;
+    }
+
+    /* both legacy and new API netdevs in use, fall back to runtime test: */
+    return (netif->dev->driver->confirm_send == NULL);
+}
+
+/**
+ * @brief   Check if the device belonging to the given netif uses the new
+ *          netdev API
+ *
+ * @see gnrc_netif_netdev_legacy_api
+ *
+ * @see netdev_driver_t::confirm_send
+ */
+static inline bool gnrc_netif_netdev_new_api(gnrc_netif_t *netif)
+{
+    return !gnrc_netif_netdev_legacy_api(netif);
+}
+
 /**
  * @see gnrc_netif_ops_t
  */