contrib: add script to test IPv6 prefix delegation

Add a script to test IPv6 prefix delegation with NM, in different
modes.

contrib/scripts/test-prefix-delegation.sh

@@ -0,0 +1,151 @@
+#!/bin/sh
+
+# Usage: ./test-prefix-delegation {ll|slaac|dhcp-stateful|dhcp-stateless}
+
+MODE=${1:-dhcp-stateful}
+
+cleanup()
+{
+    pkill -F dhcpd.pid
+    pkill -F radvd.pid
+    rm -f radvd.conf
+    rm -f dhcpd.conf
+    rm -f leases.conf
+    nmcli connection delete v1+ v2+
+    ip netns del ns1
+    ip netns del ns2
+    ip link del v1
+    ip link del v2
+}
+
+require()
+{
+    if ! command -v "$1" > /dev/null ; then
+        echo " *** Error: command '$1' not found"
+        exit 1
+    fi
+}
+
+exit_hook()
+{
+    cleanup > /dev/null 2>&1
+}
+
+require nmcli
+require ip
+require jq
+require radvd
+require dhcpd
+
+unalias ip 2> /dev/null
+
+cleanup
+trap exit_hook EXIT
+
+# ns1 is the 'upstream' namespace that provides IPv6 connectivity
+# through RA and DHCPv6. The DHCP server also acts as a delegating
+# router for /60 prefixes.
+
+# ns2 is the 'downstream' namespace where a client obtains IPv6
+# connectivity through RA from NM.
+
+# NM is in the default namespace and has a connection to ns1 with
+# ipv6.method=auto and to ns2 with ipv6.method=shared.
+
+ip netns add ns1
+ip netns add ns2
+
+ip link add v1 type veth peer name v1p
+ip link add v2 type veth peer name v2p
+
+ip link set v1p netns ns1
+ip link set v2p netns ns2
+
+ip link set v1 up
+ip link set v2 up
+
+ip -n ns1 link set v1p up
+ip -n ns1 addr add dev v1p fc01::1/64
+
+ip -n ns2 link set v2p up
+
+if [ "$MODE" = ll ]; then
+    adv_managed=off
+    adv_other=off
+elif [ "$MODE" = slaac ]; then
+    adv_managed=off
+    adv_other=off
+    adv_prefix="prefix fc01::/64 {AdvOnLink on; AdvAutonomous on; AdvRouterAddr off; };"
+elif [ "$MODE" = dhcp-stateless ]; then
+    adv_managed=off
+    adv_other=on
+    adv_prefix="prefix fc01::/64 {AdvOnLink on; AdvAutonomous on; AdvRouterAddr off; };"
+elif [ "$MODE" = dhcp-stateful ]; then
+    adv_managed=on
+    adv_other=off
+    dhcp_range="range6  fc01::1000 fc01::ffff;"
+else
+    echo "Unknown mode '$MODE'"
+    exit 1
+fi
+
+echo "Starting in $MODE mode..."
+
+cat > radvd.conf <<EOF
+interface v1p {
+        AdvSendAdvert on;
+        AdvManagedFlag ${adv_managed};
+        AdvOtherConfigFlag ${adv_other};
+        MinRtrAdvInterval 3;
+        MaxRtrAdvInterval 60;
+        ${adv_prefix}
+};
+EOF
+
+cat > dhcpd.conf <<EOF
+subnet6 fc01::/64 {
+        ${dhcp_range}
+        prefix6 fc01:bbbb:1:: fc01:bbbb:2:: / 60;
+        option dhcp6.name-servers fc01::8888;
+}
+EOF
+
+echo > leases.conf
+ip netns exec ns1 radvd -n -C radvd.conf -p radvd.pid &
+ip netns exec ns1 dhcpd -6 -d -cf dhcpd.conf -lf leases.conf -pf dhcpd.pid &
+
+nmcli connection add type ethernet ifname v1 con-name v1+ ipv4.method disabled ipv6.method auto autoconnect no
+nmcli connection add type ethernet ifname v2 con-name v2+ ipv4.method disabled ipv6.method shared autoconnect no
+
+nmcli connection up v1+
+
+sleep 5
+
+nmcli connection up v2+
+
+sleep 5
+
+ip a show dev v1
+ip a show dev v2
+
+addr=$(ip -j addr show dev v1 | jq -r '.[0].addr_info[] | select(.scope=="link")'.local)
+prefix="fc01:bbbb:1::/32"
+ip netns exec ns1 ip route add $prefix via $addr dev v1p
+
+# kernel does IPv6 autoconf in ns2 ...
+
+sleep 10
+
+# check connectivity to ns1
+if ! ip -n ns2 a show dev v2p | grep 'fc01:bbbb:[a-f0-9\:]\+/64'; then
+    ip -n ns2 a show dev v2p
+    echo "ERROR: no address"
+    exit 1
+fi
+
+if ! ip netns exec ns2 ping -c2 fc01::1; then
+    echo "ERROR: ping failed"
+    exit 1
+fi
+
+echo "OK"