examples/gnrc_border_router: add CDC-ECM uplink

Optionally executes pyterm from CDC-ECM start_network.sh

The shell script exits and cleans up instantly unless there is a
blocking program running at the end. Users can supply a serial port to
display in pyterm, or alternatively just wait if it is a "headless"
deployment.

dist/tools/usb-cdc-ecm/start_network.sh

@@ -0,0 +1,104 @@
+#!/bin/sh
+
+USB_CDC_ECM_DIR="$(dirname $(readlink -f $0))"
+
+INTERFACE_CHECK_COUNTER=5  # 5 attempts to find usb interface
+
+find_interface() {
+    INTERFACE=$(ls -A /sys/bus/usb/drivers/cdc_ether/*/net/ 2>/dev/null)
+    INTERFACE_CHECK=$(echo -n ${INTERFACE} | head -c1 | wc -c)
+    if [ ${INTERFACE_CHECK} -eq 0 -a ${INTERFACE_CHECK_COUNTER} != 0 ]; then
+        # We want to have multiple opportunities to find the USB interface
+        # as sometimes it can take a few seconds for it to enumerate after
+        # the device has been flashed.
+        sleep 1
+        ((INTERFACE_CHECK_COUNTER=INTERFACE_CHECK_COUNTER-1))
+        find_interface
+    fi
+    INTERFACE=${INTERFACE%/}
+}
+
+echo "Waiting for network interface."
+find_interface
+
+if [ ${INTERFACE_CHECK} -eq 0 ]; then
+    echo "Unable to find network interface"
+    exit 1
+else
+    echo "Found interface: ${INTERFACE}"
+fi
+
+setup_interface() {
+    sysctl -w net.ipv6.conf.${INTERFACE}.forwarding=1
+    sysctl -w net.ipv6.conf.${INTERFACE}.accept_ra=0
+    ip link set ${INTERFACE} up
+    ip a a fe80::1/64 dev ${INTERFACE}
+    ip a a fd00:dead:beef::1/128 dev lo
+    ip route add ${PREFIX} via fe80::2 dev ${INTERFACE}
+}
+
+cleanup_interface() {
+    ip a d fe80::1/64 dev ${INTERFACE}
+    ip a d fd00:dead:beef::1/128 dev lo
+    ip route del ${PREFIX} via fe80::2 dev ${INTERFACE}
+}
+
+cleanup() {
+    echo "Cleaning up..."
+    cleanup_interface
+    if [ -n "${UHCPD_PID}" ]; then
+        kill ${UHCPD_PID}
+    fi
+    if [ -n "${DHCPD_PIDFILE}" ]; then
+        kill "$(cat ${DHCPD_PIDFILE})"
+        rm "${DHCPD_PIDFILE}"
+    fi
+    trap "" INT QUIT TERM EXIT
+}
+
+start_uhcpd() {
+    ${UHCPD} ${INTERFACE} ${PREFIX} > /dev/null &
+    UHCPD_PID=$!
+}
+
+start_dhcpd() {
+    DHCPD_PIDFILE=$(mktemp)
+    ${DHCPD} -d -p ${DHCPD_PIDFILE} ${INTERFACE} ${PREFIX} 2> /dev/null
+}
+
+if [ "$1" = "-d" ] || [ "$1" = "--use-dhcpv6" ]; then
+    USE_DHCPV6=1
+    shift 1
+else
+    USE_DHCPV6=0
+fi
+
+PREFIX=$1
+[ -z "${PREFIX}" ] && {
+    echo "usage: $0 [-d|--use-dhcpv6] <prefix> [<serial-port>]"
+    exit 1
+}
+
+if [ ! -z "$2" ]; then
+    PORT=$2
+fi
+
+trap "cleanup" INT QUIT TERM EXIT
+
+setup_interface
+
+if [ ${USE_DHCPV6} -eq 1 ]; then
+    DHCPD="$(readlink -f "${USB_CDC_ECM_DIR}/../dhcpv6-pd_ia/")/dhcpv6-pd_ia.py"
+    start_dhcpd
+else
+    UHCPD="$(readlink -f "${USB_CDC_ECM_DIR}/../uhcpd/bin")/uhcpd"
+    start_uhcpd
+fi
+
+if [ -z "${PORT}" ]; then
+    echo "Network enabled over CDC-ECM"
+    read -n 1 -s -p "Press any key to stop"
+    echo
+else
+    ${USB_CDC_ECM_DIR}/../pyterm/pyterm -p "${PORT}"
+fi

examples/gnrc_border_router/Makefile

@@ -11,8 +11,8 @@ RIOTBASE ?= $(CURDIR)/../..
 UPLINK ?= ethos
 
 # Check if the selected Uplink is valid
-ifeq (,$(filter ethos slip wifi,$(UPLINK)))
-  $(error Supported uplinks are `ethos`, `slip` and `wifi`)
+ifeq (,$(filter ethos slip cdc-ecm wifi,$(UPLINK)))
+  $(error Supported uplinks are `ethos`, `slip`, `cdc-ecm` and `wifi`)
 endif
 
 # Set the SSID and password of your WiFi network here
@@ -89,6 +89,8 @@ ifeq (,$(filter native,$(BOARD)))
     # ethos baudrate can be configured from make command
     ETHOS_BAUDRATE ?= 115200
     include $(CURDIR)/Makefile.ethos.conf
+  else ifeq (cdc-ecm,$(UPLINK))
+    include $(CURDIR)/Makefile.cdc-ecm.conf
   else ifeq (wifi,$(UPLINK))
     # SSID and Password need to be configured
     include $(CURDIR)/Makefile.wifi.conf

examples/gnrc_border_router/Makefile.cdc-ecm.conf

@@ -0,0 +1,12 @@
+# USB Modules
+USEMODULE += auto_init_usbus
+USEMODULE += usbus_cdc_ecm
+
+ifeq (1,$(USE_DHCPV6))
+  FLAGS_EXTRAS += --use-dhcpv6
+endif
+
+# Configure terminal parameters for UHCP
+TERMDEPS += host-tools
+TERMPROG ?= sudo sh $(RIOTTOOLS)/usb-cdc-ecm/start_network.sh
+TERMFLAGS ?= $(FLAGS_EXTRAS) $(IPV6_PREFIX) $(PORT)