refactor: introduce a helper

weave

@@ -52,7 +52,7 @@ COMMAND=$1
 
 shift 1
 
-check_command_and_run() {
+check_command_and_run_anything() {
     if command_exists $1
     then
         shift 1
@@ -62,6 +62,10 @@ check_command_and_run() {
     fi
 }
 
+check_command_and_run() {
+    check_command_and_run_anything $1 "$@"
+}
+
 is_cidr() {
     # The regexp here is far from precise, but good enough.
     echo "$1" | grep -E '^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/[0-9]{1,2}$' >/dev/null
@@ -119,7 +123,7 @@ create_bridge() {
         ip link set dev v${CONTAINER_IFNAME}du master $BRIDGE
         ip link del dev v${CONTAINER_IFNAME}du
         # disable offloading
-        check_command_and_run ethtool ethtool -K $BRIDGE tx off >/dev/null
+        check_command_and_run ethtool -K $BRIDGE tx off >/dev/null
         # Work around the situation where there are no rules allowing traffic
         # across our bridge. E.g. ufw
         add_iptables_rule filter FORWARD -i $BRIDGE -o $BRIDGE -j ACCEPT
@@ -213,7 +217,7 @@ connect_container_to_bridge() {
 launch() {
     connect_container_to_bridge &&
         ip netns exec $NETNS ip link set $CONTAINER_IFNAME up &&
-        check_command_and_run ethtool ip netns exec $NETNS ethtool -K eth0 tx off >/dev/null
+        check_command_and_run_anything ethtool ip netns exec $NETNS ethtool -K eth0 tx off >/dev/null
 }
 
 attach() {
@@ -235,7 +239,7 @@ attach() {
     if ! connect_container_to_bridge ||
         ! ip netns exec $NETNS ip addr add $1 dev $CONTAINER_IFNAME ||
         ! ip netns exec $NETNS ip link set $CONTAINER_IFNAME up ||
-        ! check_command_and_run ethtool ip netns exec $NETNS ethtool -K $CONTAINER_IFNAME tx off >/dev/null ; then
+        ! check_command_and_run_anything ethtool ip netns exec $NETNS ethtool -K $CONTAINER_IFNAME tx off >/dev/null ; then
         return 1
     fi
 
@@ -523,7 +527,7 @@ case "$COMMAND" in
         docker kill  $DNS_CONTAINER_NAME >/dev/null 2>&1 || true
         docker rm -f $CONTAINER_NAME     >/dev/null 2>&1 || true
         docker rm -f $DNS_CONTAINER_NAME >/dev/null 2>&1 || true
-        check_command_and_run conntrack conntrack -D -p udp --dport $PORT >/dev/null 2>&1 || true
+        check_command_and_run conntrack -D -p udp --dport $PORT >/dev/null 2>&1 || true
         ;;
     reset)
         [ $# -eq 0 ] || usage
@@ -531,7 +535,7 @@ case "$COMMAND" in
         docker kill  $DNS_CONTAINER_NAME >/dev/null 2>&1 || true
         docker rm -f $CONTAINER_NAME     >/dev/null 2>&1 || true
         docker rm -f $DNS_CONTAINER_NAME >/dev/null 2>&1 || true
-        check_command_and_run conntrack conntrack -D -p udp --dport $PORT >/dev/null 2>&1 || true
+        check_command_and_run conntrack -D -p udp --dport $PORT >/dev/null 2>&1 || true
         destroy_bridge
         for LOCAL_IFNAME in $(ip link show | grep v${CONTAINER_IFNAME}pl | cut -d ' ' -f 2 | tr -d ':') ; do
             ip link del $LOCAL_IFNAME