document tun assignment

src/ip-lease.c

@@ -105,6 +105,10 @@ struct ip_lease_st t;
 
 void steal_ip_leases(struct proc_st* proc, struct proc_st *thief)
 {
+	/* here we reset the old tun device, and assign the old addresses
+	 * to a new device. We cannot re-use the old device because the
+	 * fd is only available to the worker process and not here (main)
+	 */
 	reset_tun(proc);
 
 	thief->ipv4 = talloc_move(thief, &proc->ipv4);