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diff --git a/src/charon/bus/bus.h b/src/charon/bus/bus.h
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+/**
+ * @file bus.h
+ *
+ * @brief Interface of bus_t.
+ *
+ */
+
+/*
+ * Copyright (C) 2006 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#ifndef BUS_H_
+#define BUS_H_
+
+typedef enum signal_t signal_t;
+typedef enum level_t level_t;
+typedef struct bus_listener_t bus_listener_t;
+typedef struct bus_t bus_t;
+
+#include <stdarg.h>
+
+#include <sa/ike_sa.h>
+#include <sa/child_sa.h>
+
+
+/**
+ * @brief signals emitted by the daemon.
+ *
+ * Signaling is for different purporses. First, it allows debugging via
+ * "debugging signal messages", sencondly, it allows to follow certain
+ * mechanisms currently going on in the daemon. As we are multithreaded, 
+ * and of multiple transactions are involved, it's not possible to follow
+ * one connection setup without further infrastructure. These infrastructure
+ * is provided by the bus and the signals the daemon emits to the bus.
+ *
+ * There are different scenarios to follow these signals, but all have
+ * the same scheme. First, a START signal is emitted to indicate the daemon
+ * has started to 
+ *
+ * @ingroup bus
+ */
+enum signal_t {
+	/** pseudo signal, representing any other signal */
+	SIG_ANY,
+	
+	/** debugging message from daemon main loop */
+	DBG_DMN,
+	/** debugging message from IKE_SA_MANAGER */
+	DBG_MGR,
+	/** debugging message from an IKE_SA */
+	DBG_IKE,
+	/** debugging message from a CHILD_SA */
+	DBG_CHD,
+	/** debugging message from job processing */
+	DBG_JOB,
+	/** debugging message from configuration backends */
+	DBG_CFG,
+	/** debugging message from kernel interface */
+	DBG_KNL,
+	/** debugging message from networking */
+	DBG_NET,
+	/** debugging message from message encoding/decoding */
+	DBG_ENC,
+	/** debugging message from libstrongswan via logging hook */
+	DBG_LIB,
+	
+	/** number of debug signals */
+	DBG_MAX,
+	
+	/** signals for IKE_SA establishment */
+	IKE_UP_START,
+	IKE_UP_SUCCESS,
+	IKE_UP_FAILED,
+	
+	/** signals for IKE_SA delete */
+	IKE_DOWN_START,
+	IKE_DOWN_SUCCESS,
+	IKE_DOWN_FAILED,
+	
+	/** signals for IKE_SA rekeying */
+	IKE_REKEY_START,
+	IKE_REKEY_SUCCESS,
+	IKE_REKEY_FAILED,
+	
+	/** signals for CHILD_SA establishment */
+	CHILD_UP_START,
+	CHILD_UP_SUCCESS,
+	CHILD_UP_FAILED,
+	
+	/** signals for CHILD_SA delete */
+	CHILD_DOWN_START,
+	CHILD_DOWN_SUCCESS,
+	CHILD_DOWN_FAILED,
+	
+	/** signals for CHILD_SA rekeying */
+	CHILD_REKEY_START,
+	CHILD_REKEY_SUCCESS,
+	CHILD_REKEY_FAILED,
+	
+	/** signals for CHILD_SA routing */
+	CHILD_ROUTE_START,
+	CHILD_ROUTE_SUCCESS,
+	CHILD_ROUTE_FAILED,
+	
+	/** signals for CHILD_SA routing */
+	CHILD_UNROUTE_START,
+	CHILD_UNROUTE_SUCCESS,
+	CHILD_UNROUTE_FAILED,
+	
+	SIG_MAX
+};
+
+/**
+ * short names of signals using 3 chars
+ */
+extern enum_name_t *signal_names;
+
+/**
+ * Signal levels used to control output verbosity.
+ */
+enum level_t {
+	/** numerical levels from 0 to 4 */
+	LEVEL_0 = 0,
+	LEVEL_1 = 1,
+	LEVEL_2 = 2,
+	LEVEL_3 = 3,
+	LEVEL_4 = 4,
+	/** absolutely silent, no signal is emitted with this level */
+	LEVEL_SILENT = -1,
+	/** alias for numberical levels */
+	LEVEL_AUDIT = LEVEL_0,
+	LEVEL_CTRL = LEVEL_1,
+	LEVEL_CTRLMORE = LEVEL_2,
+	LEVEL_RAW = LEVEL_3,
+	LEVEL_PRIVATE = LEVEL_4,
+};
+
+#ifndef DEBUG_LEVEL
+# define DEBUG_LEVEL 4
+#endif /* DEBUG_LEVEL */
+
+#if DEBUG_LEVEL >= 1
+/**
+ * @brief Log a debug message via the signal bus.
+ *
+ * @param signal	signal_t signal description
+ * @param format	printf() style format string
+ * @param ...		printf() style agument list
+ */
+# define DBG1(sig, format, ...) charon->bus->signal(charon->bus, sig, LEVEL_1, format, ##__VA_ARGS__)
+#endif /* DEBUG_LEVEL */
+#if DEBUG_LEVEL >= 2
+#define DBG2(sig, format, ...) charon->bus->signal(charon->bus, sig, LEVEL_2, format, ##__VA_ARGS__)
+#endif /* DEBUG_LEVEL */
+#if DEBUG_LEVEL >= 3
+#define DBG3(sig, format, ...) charon->bus->signal(charon->bus, sig, LEVEL_3, format, ##__VA_ARGS__)
+#endif /* DEBUG_LEVEL */
+#if DEBUG_LEVEL >= 4
+#define DBG4(sig, format, ...) charon->bus->signal(charon->bus, sig, LEVEL_4, format, ##__VA_ARGS__)
+#endif /* DEBUG_LEVEL */
+
+#ifndef DBG1
+# define DBG1(...) {}
+#endif /* DBG1 */
+#ifndef DBG2
+# define DBG2(...) {}
+#endif /* DBG2 */
+#ifndef DBG3
+# define DBG3(...) {}
+#endif /* DBG3 */
+#ifndef DBG4
+# define DBG4(...) {}
+#endif /* DBG4 */
+
+/**
+ * @brief Raise a signal for an occured event.
+ *
+ * @param sig		signal_t signal description
+ * @param format	printf() style format string
+ * @param ...		printf() style agument list
+ */
+#define SIG(sig, format, ...) charon->bus->signal(charon->bus, sig, LEVEL_0, format, ##__VA_ARGS__)
+
+/**
+ * @brief Get the type of a signal.
+ *
+ * A signal may be a debugging signal with a specific context. They have
+ * a level specific for their context > 0. All audit signals use the
+ * type 0. This allows filtering of singals by their type.
+ *
+ * @param signal	signal to get the type from
+ * @return			type of the signal, between 0..(DBG_MAX-1)
+ */
+#define SIG_TYPE(sig) (sig > DBG_MAX ? SIG_ANY : sig)
+
+
+/**
+ * @brief Interface for registering at the signal bus.
+ *
+ * To receive signals from the bus, the client implementing the
+ * bus_listener_t interface registers itself at the signal bus.
+ *
+ * @ingroup bus
+ */
+struct bus_listener_t {
+	
+	/**
+	 * @brief Send a signal to a bus listener.
+	 *
+	 * A numerical identification for the thread is included, as the
+	 * associated IKE_SA, if any. Signal specifies the type of
+	 * the event occured. The format string specifies
+	 * an additional informational or error message with a printf() like
+	 * variable argument list. This is in the va_list form, as forwarding
+	 * a "..." parameters to functions is not (cleanly) possible.
+	 * The implementing signal function returns TRUE to stay registered
+	 * to the bus, or FALSE to unregister itself.
+	 *
+	 * @param this		listener
+	 * @param singal	kind of the signal (up, down, rekeyed, ...)
+	 * @param level		verbosity level of the signal
+	 * @param thread	ID of the thread raised this signal
+	 * @param ike_sa	IKE_SA associated to the event
+	 * @param format	printf() style format string
+	 * @param args		vprintf() style va_list argument list
+	 " @return			TRUE to stay registered, FALSE to unregister
+	 */
+	bool (*signal) (bus_listener_t *this, signal_t signal, level_t level,
+					int thread, ike_sa_t *ike_sa, char* format, va_list args);
+};
+
+/**
+ * @brief Signal bus which sends signals to registered listeners.
+ *
+ * The signal bus is not much more than a multiplexer. A listener interested
+ * in receiving event signals registers at the bus. Any signals sent to
+ * are delivered to all registered listeners.
+ * To deliver signals to threads, the blocking listen() call may be used
+ * to wait for a signal.
+ *
+ * @ingroup bus
+ */
+struct bus_t {
+	
+	/**
+	 * @brief Register a listener to the bus.
+	 *
+	 * A registered listener receives all signals which are sent to the bus.
+	 * The listener is passive; the thread which emitted the signal
+	 * processes the listener routine.
+	 *
+	 * @param this		bus
+	 * @param listener	listener to register.
+	 */
+	void (*add_listener) (bus_t *this, bus_listener_t *listener);
+	
+	/**
+	 * @brief Listen actively on the bus.
+	 *
+	 * As we are fully multithreaded, we must provide a mechanism
+	 * for active threads to listen to the bus. With the listen() method,
+	 * a thread waits until a signal occurs, and then processes it.
+	 * To prevent the listen() calling thread to miss signals emitted while
+	 * it processes a signal, registration is required. This is done through
+	 * the set_listen_state() method, see below.
+	 *
+	 * @param this		bus
+	 * @param level		verbosity level of the signal
+	 * @param thread	receives thread number emitted the signal
+	 * @param ike_sa	receives the IKE_SA involved in the signal, or NULL
+	 * @param format	receives the format string supplied with the signal
+	 * @param va_list	receives the variable argument list for format
+	 * @return			the emitted signal type
+	 */
+	signal_t (*listen) (bus_t *this, level_t* level, int *thread,
+						ike_sa_t **ike_sa, char** format, va_list* args);
+	
+	/**
+	 * @brief Set the listening state of the calling thread.
+	 *
+	 * To prevent message loss for active listeners using listen(), threads
+	 * must register themself to the bus before starting to listen(). When
+	 * a signal occurs, the emitter waits until all threads with listen_state
+	 * TRUE are waiting in the listen() method to process the signal.
+	 * It is important that a thread with liste_state TRUE calls listen()
+	 * periodically, or sets it's listening state to FALSE; otherwise
+	 * all signal emitting threads get blocked on the bus.
+	 *
+	 * @param this		bus
+	 * @param active	TRUE to set to listening
+	 */
+	void (*set_listen_state) (bus_t *this, bool active);
+	
+	/**
+	 * @brief Set the IKE_SA the calling thread is using.
+	 *
+	 * To associate an received signal to an IKE_SA without passing it as
+	 * parameter each time, the thread registers it's used IKE_SA each
+	 * time it checked it out. Before checking it in, the thread unregisters
+	 * the IKE_SA (by passing NULL). This IKE_SA is stored per-thread, so each
+	 * thread has one IKE_SA registered (or not).
+	 * 
+	 * @param this		bus
+	 * @param ike_sa	ike_sa to register, or NULL to unregister
+	 */
+	void (*set_sa) (bus_t *this, ike_sa_t *ike_sa);
+	
+	/**
+	 * @brief Send a signal to the bus.
+	 *
+	 * The signal specifies the type of the event occured. The format string
+	 * specifies an additional informational or error message with a
+	 * printf() like variable argument list.
+	 * Some useful macros are available to shorten this call.
+	 * @see SIG(), DBG1()
+	 *
+	 * @param this		bus
+	 * @param singal	kind of the signal (up, down, rekeyed, ...)
+	 * @param level		verbosity level of the signal
+	 * @param format	printf() style format string
+	 * @param ...		printf() style argument list
+	 */
+	void (*signal) (bus_t *this, signal_t signal, level_t level, char* format, ...);
+	
+	/**
+	 * @brief Send a signal to the bus using va_list arguments.
+	 *
+	 * Same as bus_t.signal(), but uses va_list argument list.
+	 *
+	 * @param this		bus
+	 * @param singal	kind of the signal (up, down, rekeyed, ...)
+	 * @param level		verbosity level of the signal
+	 * @param format	printf() style format string
+	 * @param args		va_list arguments
+	 */
+	void (*vsignal) (bus_t *this, signal_t signal, level_t level, char* format, va_list args);
+	
+	/**
+	 * @brief Destroy the signal bus.
+	 *
+	 * @param this		bus to destroy
+	 */
+	void (*destroy) (bus_t *this);
+};
+
+/**
+ * @brief Create the signal bus which multiplexes signals to its listeners.
+ *
+ * @return		signal bus instance
+ * 
+ * @ingroup bus
+ */
+bus_t *bus_create();
+
+#endif /* BUS_H_ */