BAC: Factor creating new hosts into xnewhost

namespace_demo/lib.sh

@@ -2,6 +2,23 @@
 
 PID=$$
 
+# `xnewhost <name>` creates new virtual host.
+xnewhost() {
+    local X=$1
+    # lo
+    xunshare $X -- ip link set lo up
+
+    # private /var/run so that e.g. smcrouted can be started
+    xnsenter $X -- mount -t tmpfs none /var/run
+
+    # open terminal inside the host for play
+    local nterm=${2:-1}
+    for i in `seq $nterm`; do
+        xnsenter $X -- xfce4-terminal --title=$X$i &
+    done
+}
+
+
 # `xunshare <dir> ...`  -- unshare net/mount/... namespaces to be referenced by dir
 xunshare() {
     ref=$1

namespace_demo/topo-B-A-C.sh

@@ -25,10 +25,10 @@
 cycle=n
 [ "$1" = "-cycle" ] && cycle=y
 
-# lo on everything
-xunshare A -- ip link set lo up
-xunshare B -- ip link set lo up
-xunshare C -- ip link set lo up
+# set up hosts
+xnewhost A 2
+xnewhost B
+xnewhost C
 
 # links
 xlink B A   # B-A
@@ -58,16 +58,3 @@ if [ $cycle = y ]; then
     xnsenter B -- ip route append 224.0.0.0/4 dev b-c
     xnsenter C -- ip route append 224.0.0.0/4 dev c-b
 fi
-
-
-# mount private /var/run so that smcrouted can be started
-xnsenter A -- mount -t tmpfs none /var/run
-xnsenter B -- mount -t tmpfs none /var/run
-xnsenter C -- mount -t tmpfs none /var/run
-
-
-# open terminals in A B C for play
-xnsenter B -- xfce4-terminal --title=B &
-xnsenter C -- xfce4-terminal --title=C &
-xnsenter A -- xfce4-terminal --title=A &
-xnsenter A -- xfce4-terminal --title=A2 &