From 15ab9bbdcda705c1c4bb10bd49ffd49907a96754 Mon Sep 17 00:00:00 2001
From: Benjamin Valentin <benjamin.valentin@ml-pa.com>
Date: Fri, 15 Oct 2021 17:37:40 +0200
Subject: [PATCH] tools/usb-cdc-ecm: add support for radvd / auto_subnets

---
 dist/tools/usb-cdc-ecm/start_network.sh       | 23 +++++++++++++++++--
 .../gnrc_border_router/Makefile.cdc-ecm.conf  |  4 +++-
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/dist/tools/usb-cdc-ecm/start_network.sh b/dist/tools/usb-cdc-ecm/start_network.sh
index 0684c61758..cf72f07b60 100755
--- a/dist/tools/usb-cdc-ecm/start_network.sh
+++ b/dist/tools/usb-cdc-ecm/start_network.sh
@@ -34,7 +34,6 @@ setup_interface() {
     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() {
@@ -57,15 +56,25 @@ cleanup() {
 }
 
 start_uhcpd() {
+    ip route add "${PREFIX}" via fe80::2 dev "${INTERFACE}"
     ${UHCPD} "${INTERFACE}" "${PREFIX}" > /dev/null &
     UHCPD_PID=$!
 }
 
 start_dhcpd() {
+    ip route add "${PREFIX}" via fe80::2 dev "${INTERFACE}"
     DHCPD_PIDFILE=$(mktemp)
     ${DHCPD} -d -p "${DHCPD_PIDFILE}" "${INTERFACE}" "${PREFIX}" 2> /dev/null
 }
 
+start_radvd() {
+    ADDR=$(echo "${PREFIX}" | sed -e 's/::\//::1\//')
+    ip a a "${ADDR}" dev "${INTERFACE}"
+    sysctl net.ipv6.conf."${INTERFACE}".accept_ra=2
+    sysctl net.ipv6.conf."${INTERFACE}".accept_ra_rt_info_max_plen=64
+    ${RADVD} -c "${INTERFACE}" "${PREFIX}"
+}
+
 if [ "$1" = "-d" ] || [ "$1" = "--use-dhcpv6" ]; then
     USE_DHCPV6=1
     shift 1
@@ -73,9 +82,16 @@ else
     USE_DHCPV6=0
 fi
 
+if [ "$1" = "-r" ] || [ "$1" = "--use-radvd" ]; then
+    USE_RADVD=1
+    shift 1
+else
+    USE_RADVD=0
+fi
+
 PREFIX=$1
 [ -z "${PREFIX}" ] && {
-    echo "usage: $0 [-d|--use-dhcpv6] <prefix> [<serial-port>]"
+    echo "usage: $0 [-d|--use-dhcpv6] [-r|--use-radvd ] <prefix> [<serial-port>]"
     exit 1
 }
 
@@ -90,6 +106,9 @@ setup_interface
 if [ ${USE_DHCPV6} -eq 1 ]; then
     DHCPD="$(readlink -f "${USB_CDC_ECM_DIR}/../dhcpv6-pd_ia/")/dhcpv6-pd_ia.py"
     start_dhcpd
+elif [ ${USE_RADVD} -eq 1 ]; then
+    RADVD="$(readlink -f "${USB_CDC_ECM_DIR}/../radvd/")/radvd.sh"
+    start_radvd
 else
     UHCPD="$(readlink -f "${USB_CDC_ECM_DIR}/../uhcpd/bin")/uhcpd"
     start_uhcpd
diff --git a/examples/gnrc_border_router/Makefile.cdc-ecm.conf b/examples/gnrc_border_router/Makefile.cdc-ecm.conf
index 0f46566bc9..8c86a6afbc 100644
--- a/examples/gnrc_border_router/Makefile.cdc-ecm.conf
+++ b/examples/gnrc_border_router/Makefile.cdc-ecm.conf
@@ -2,8 +2,10 @@
 USEMODULE += auto_init_usbus
 USEMODULE += usbus_cdc_ecm
 
-ifeq (dhcpv6, $(PREFIX_CONF))
+ifeq (dhcpv6,$(PREFIX_CONF))
   FLAGS_EXTRAS += --use-dhcpv6
+else ifeq (auto_subnets,$(PREFIX_CONF))
+  FLAGS_EXTRAS += --use-radvd
 endif
 
 # Configure terminal parameters for UHCP