tapsetup: add capability to list bridges

dist/tools/tapsetup/tapsetup

@@ -17,6 +17,9 @@ usage() {
     echo "Options:" >&2
     echo "   -c [<num>], --create [<num>]: Create <num> tap interfaces (default: 2)" >&2
     echo "   -d, --delete:                 Delete all interface" >&2
+    echo "   -l <iface>, --list <iface>:   If <iface> belongs to a bridge, list the bridge and" >&2
+    echo "                                 all interfaces that belong to it. If <iface> does " >&2
+    echo"                                  not belong to a bridge, just print <iface>." >&2
     echo "   -b <name>, --bridge <name>:   Give name for the bridge (default: tapbr)" >&2
     echo "   -t <name>, --tap <name>:      Name base for the tap interfaces; the" >&2
     echo "                                 generated names will be <name>x" >&2
@@ -148,6 +151,50 @@ create_tap() {
     esac
 }
 
+get_master() {
+    IFACE=$1
+    case "${PLATFORM}" in
+        Linux)
+            MASTER=$(ip link show ${IFACE} | grep -o "master \S\+" | cut -d' ' -f2)
+            ;;
+        FreeBSD|OSX)
+            for IF in $(ifconfig | grep -oiE "^[a-z0-9_-]+"); do
+                if ifconfig $IF | grep -q "member: $IFACE"; then
+                    MASTER=${IF}
+                    break
+                fi
+            done
+            ;;
+        *)
+            ;;
+    esac
+    if [ -z "$MASTER" ]; then
+        # IFACE is its own master
+        echo "$IFACE"
+    else
+        echo "$MASTER"
+    fi
+}
+
+list_bridge() {
+    BRIDGE=$1
+    echo "$BRIDGE:"
+    case "${PLATFORM}" in
+        Linux)
+            for IF in $(ls /sys/class/net/${BRIDGE}/brif); do
+                echo "- $IF"
+            done
+            ;;
+        FreeBSD|OSX)
+            for IF in $(ifconfig ${BRIDGE} | grep -oiE "member: .+ " | cut -d' ' -f2); do
+                echo "- $IF"
+            done
+            ;;
+        *)
+            ;;
+    esac
+}
+
 while true ; do
     case "$1" in
         -6)
@@ -185,6 +232,20 @@ while true ; do
             fi
             COMMAND="delete"
             shift ;;
+        -l|--list)
+            if [ -n "${COMMAND}" ]; then
+                usage
+                exit 2
+            fi
+            COMMAND="list"
+            case "$2" in
+                "")
+                    usage
+                    exit 2 ;;
+                *)
+                    BRNAME="$2"
+                    shift 2 ;;
+            esac ;;
         -h|--help)
             usage
             exit ;;
@@ -213,13 +274,13 @@ while true ; do
     esac
 done
 
-if [ -z "${SUDO_USER}" ]; then
-    echo 'Environment variable $SUDO_USER required; Please run with `sudo`'
-    exit 1
-fi
 if [ -z "${COMMAND}" ]; then
     COMMAND="create"
 fi
+if [ -z "${SUDO_USER}" ] && [ "${COMMAND}" != "list" ]; then
+    echo 'Environment variable $SUDO_USER required; Please run with `sudo`'
+    exit 1
+fi
 case "$(uname -s)" in
     Darwin)
         PLATFORM="OSX"
@@ -251,6 +312,8 @@ if [ "${COMMAND}" = 'create' ]; then
 
 elif [ "${COMMAND}" = 'delete' ]; then
     delete_bridge
+elif [ "${COMMAND}" = 'list' ]; then
+    list_bridge $(get_master "$BRNAME")
 else
     echo 'unknown command'
     exit 1