CONN_DEVICE_NAME is configurable by env var

get_ip_addr.sh

@@ -7,21 +7,22 @@ if [ -z "${ip_version:-}" ] || ([ "$ip_version" != 4 ] && [ "$ip_version" != 6 ]
 fi
 
 if [ $ip_version = 4 ]; then
-    curl -4 http://icanhazip.com 2> /dev/null
-    exit 0
+    dig +short myip.opendns.com @resolver1.opendns.com \
+        && exit 0 \
+        || exit 1
 fi
 
 set -eu
 CONN_NAME=${CONN_NAME:-nevis}
-conn_device_name="$(nmcli --fields NAME,DEVICE con show | grep ^$CONN_NAME | sed 's/\s\+/ /g' | cut -d' ' -f 2)"
-if [ -z "${conn_device_name:-}" ]; then
+CONN_DEVICE_NAME="${CONN_DEVICE_NAME:-$(nmcli --fields NAME,DEVICE con show | grep ^$CONN_NAME | sed 's/\s\+/ /g' | cut -d' ' -f 2)}"
+if [ -z "${CONN_DEVICE_NAME:-}" ]; then
     echo "Could not find the connection device name for connection: \"$CONN_NAME\"" >&2
     exit 1
 fi
 
-device_line_no="$(ip addr | grep -En ^[0-9]+:\ $conn_device_name | cut -d':' -f 1)"
+device_line_no="$(ip addr | grep -En ^[0-9]+:\ $CONN_DEVICE_NAME | cut -d':' -f 1)"
 if [ -z "${device_line_no:-}" ]; then
-    echo "Could not find device: \"$conn_device_name\" in output of ip addr" >&2
+    echo "Could not find device: \"$CONN_DEVICE_NAME\" in output of ip addr" >&2
     exit 1
 fi
 
@@ -44,7 +45,7 @@ else
 fi
 ip="$(echo "$ip_addr_output_for_device" | grep "scope global" | grep -oE $ip_regex | head -n 1)"
 if [ -z "${ip:-}" ]; then
-    echo "Could not find global IP in output of ip addr under device: $conn_device_name ($CONN_NAME)"
+    echo "Could not find global IP in output of ip addr under device: $CONN_DEVICE_NAME ($CONN_NAME)"
     exit 1
 fi