entrypoints root was changed, additional scripts added

scripts/entrypoint.sh

@@ -0,0 +1,58 @@
+#!/usr/bin/env bash
+
+# A bridge of this name will be created to host the TAP interface created for
+# the VM
+QEMU_BRIDGE='qemubr0'
+
+# DHCPD must have an IP address to run, but that address doesn't have to
+# be valid. This is the dummy address dhcpd is configured to use.
+DUMMY_DHCPD_IP='10.0.0.1'
+
+# These scripts configure/deconfigure the VM interface on the bridge.
+QEMU_IFUP='/routeros/qemu-ifup'
+QEMU_IFDOWN='/routeros/qemu-ifdown'
+
+# The name of the dhcpd config file we make
+DHCPD_CONF_FILE='/routeros/dhcpd.conf'
+
+function default_intf() {
+    ip -json route show | jq -r '.[] | select(.dst == "default") | .dev'
+}
+
+# First step, we run the things that need to happen before we start mucking
+# with the interfaces. We start by generating the DHCPD config file based
+# on our current address/routes. We "steal" the container's IP, and lease
+# it to the VM once it starts up.
+/routeros/generate-dhcpd-conf.py $QEMU_BRIDGE > $DHCPD_CONF_FILE
+default_dev=`default_intf`
+
+# Now we start modifying the networking configuration. First we clear out
+# the IP address of the default device (will also have the side-effect of
+# removing the default route)
+ip addr flush dev $default_dev
+
+# Next, we create our bridge, and add our container interface to it.
+ip link add $QEMU_BRIDGE type bridge
+ip link set dev $default_dev master $QEMU_BRIDGE
+
+# Then, we toggle the interface and the bridge to make sure everything is up
+# and running.
+ip link set dev $default_dev up
+ip link set dev $QEMU_BRIDGE up
+
+# Finally, start our DHCPD server
+udhcpd -I $DUMMY_DHCPD_IP -f $DHCPD_CONF_FILE &
+
+# And run the VM! A brief explanation of the options here:
+# -enable-kvm: Use KVM for this VM (much faster for our case).
+# -nographic: disable SDL graphics.
+# -serial mon:stdio: use "monitored stdio" as our serial output.
+# -nic: Use a TAP interface with our custom up/down scripts.
+# -drive: The VM image we're booting.
+exec qemu-system-x86_64 \
+    -enable-kvm -nographic -serial mon:stdio \
+    -vnc 0.0.0.0:0 \
+    -m 256 \
+    -nic tap,id=qemu0,script=$QEMU_IFUP,downscript=$QEMU_IFDOWN \
+    "$@" \
+    -hda $ROUTEROS_IMAGE