tap-vsockd: add tap-vsockd service to bring up eth1

The tap-vsockd service is started from eth1's pre-up script.

On the Mac: the bind of the AF_HYPERV socket fails, and eth1 is skipped.
On Windows: if there is no database then eth1 is skipped.
On Windows: if the database has network=native then eth1 is brought up.

Signed-off-by: David Scott <dave.scott@docker.com>

alpine/Dockerfile

@@ -41,6 +41,7 @@ COPY packages/proxy/etc /etc/
 COPY packages/transfused/transfused /sbin/
 COPY packages/transfused/etc /etc/
 COPY packages/tap-vsockd/tap-vsockd /sbin/
+COPY packages/tap-vsockd/etc /etc/
 COPY packages/llmnrd/llmnrd /sbin/
 COPY packages/llmnrd/etc /etc/
 COPY packages/llmnrd/llmnrd.tar.gz /usr/share/src/

alpine/etc/network/interfaces

@@ -9,3 +9,5 @@ auto eth1
 iface eth1 inet dhcp
     udhcpc_opts -T 1 -A 3
     metric 199
+    pre-up service tap-vsockd start
+    post-down service tap-vsockd stop

alpine/packages/tap-vsockd/etc/init.d/tap-vsockd

@@ -0,0 +1,43 @@
+#!/sbin/openrc-run
+
+description="VPN proxy"
+
+depend()
+{
+	before networking
+}
+
+start()
+{
+        if mobyconfig exists network
+        then
+                NETWORK_MODE="$(mobyconfig get network | tr -d '[[:space:]]')"
+                if [ "${NETWORK_MODE}" = "hybrid" ]; then
+
+			ebegin "Starting VPN proxy"
+
+			PIDFILE=/var/run/tap-vsockd.pid
+			start-stop-daemon --start --quiet \
+				--exec /sbin/tap-vsockd \
+				--pidfile ${PIDFILE} \
+				-- \
+				--daemon \
+				--pidfile "${PIDFILE}" \
+				--listen
+
+			eend $? "Failed to start VPN proxy"
+		fi
+	fi
+}
+
+stop()
+{
+	ebegin "Stopping VPN proxy"
+
+	PIDFILE=/var/run/tap-vsockd.pid
+
+	start-stop-daemon --stop --quiet \
+		--pidfile "${PIDFILE}"
+
+	eend $? "Failed to stop VPN proxy"
+}