travis fixup networking

.ci-local/travis-fixup.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+set -e -u -x
+
+env|grep TRAVIS
+
+[ "$TRAVIS_OS_NAME" = "linux" ] || exit 0
+
+# Ensure there is an interface with a (correct) broadcast address
+# eg. 'trusty' VMs have interface broadcast address mis-configured
+# (why oh why do people insist on setting this explicitly?)
+
+sudo ip tuntap add dev tap42 mode tap
+
+sudo ip addr add 192.168.240.1/24 broadcast + dev tap42
+
+sudo ip link set dev tap42 up
+
+# note that this device will be UP but not RUNNING
+# so java will see it as not UP since java confuses UP and RUNNING

.travis.yml

@@ -35,6 +35,7 @@ addons:
     update: true
 
 install:
+  - ./.ci-local/travis-fixup.sh
   - ./.ci/travis/prepare.sh
 
 script: