ccss.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2010, Digium, Inc.
 *
 * Mark Michelson <mmichelson@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Call Completion Supplementary Services implementation
 * \author Mark Michelson <mmichelson@digium.com>
 */

/*! \li \ref ccss.c uses the configuration file \ref ccss.conf
 * \addtogroup configuration_file Configuration Files
 */

/*!
 * \page ccss.conf ccss.conf
 * \verbinclude ccss.conf.sample
 */

/*** MODULEINFO
	<support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "asterisk/astobj2.h"
#include "asterisk/strings.h"
#include "asterisk/ccss.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/utils.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/devicestate.h"
#include "asterisk/module.h"
#include "asterisk/app.h"
#include "asterisk/cli.h"
#include "asterisk/manager.h"
#include "asterisk/causes.h"
#include "asterisk/stasis_system.h"
#include "asterisk/format_cache.h"

/*** DOCUMENTATION
	<application name="CallCompletionRequest" language="en_US">
		<synopsis>
			Request call completion service for previous call
		</synopsis>
		<syntax />
		<description>
			<para>Request call completion service for a previously failed
			call attempt.</para>
			<para>This application sets the following channel variables:</para>
			<variablelist>
				<variable name="CC_REQUEST_RESULT">
					<para>This is the returned status of the request.</para>
					<value name="SUCCESS" />
					<value name="FAIL" />
				</variable>
				<variable name="CC_REQUEST_REASON">
					<para>This is the reason the request failed.</para>
					<value name="NO_CORE_INSTANCE" />
					<value name="NOT_GENERIC" />
					<value name="TOO_MANY_REQUESTS" />
					<value name="UNSPECIFIED" />
				</variable>
			</variablelist>
		</description>
	</application>
	<application name="CallCompletionCancel" language="en_US">
		<synopsis>
			Cancel call completion service
		</synopsis>
		<syntax />
		<description>
			<para>Cancel a Call Completion Request.</para>
			<para>This application sets the following channel variables:</para>
			<variablelist>
				<variable name="CC_CANCEL_RESULT">
					<para>This is the returned status of the cancel.</para>
					<value name="SUCCESS" />
					<value name="FAIL" />
				</variable>
				<variable name="CC_CANCEL_REASON">
					<para>This is the reason the cancel failed.</para>
					<value name="NO_CORE_INSTANCE" />
					<value name="NOT_GENERIC" />
					<value name="UNSPECIFIED" />
				</variable>
			</variablelist>
		</description>
	</application>
 ***/

/* These are some file-scoped variables. It would be
 * nice to define them closer to their first usage, but since
 * they are used in many places throughout the file, defining
 * them here at the top is easiest.
 */

/*!
 * The ast_sched_context used for all generic CC timeouts
 */
static struct ast_sched_context *cc_sched_context;
/*!
 * Counter used to create core IDs for CC calls. Each new
 * core ID is created by atomically adding 1 to the core_id_counter
 */
static int core_id_counter;
/*!
 * Taskprocessor from which all CC agent and monitor callbacks
 * are called.
 */
static struct ast_taskprocessor *cc_core_taskprocessor;
/*!
 * Name printed on all CC log messages.
 */
static const char *CC_LOGGER_LEVEL_NAME = "CC";
/*!
 * Logger level registered by the CC core.
 */
static int cc_logger_level;
/*!
 * Parsed configuration value for cc_max_requests
 */
static unsigned int global_cc_max_requests;
/*!
 * The current number of CC requests in the system
 */
static int cc_request_count;

static inline void *cc_ref(void *obj, const char *debug)
{
	ao2_t_ref(obj, +1, debug);
	return obj;
}

static inline void *cc_unref(void *obj, const char *debug)
{
	ao2_t_ref(obj, -1, debug);
	return NULL;
}

/*!
 * \since 1.8
 * \internal
 * \brief A structure for holding the configuration parameters
 * relating to CCSS
 */
struct ast_cc_config_params {
	enum ast_cc_agent_policies cc_agent_policy;
	enum ast_cc_monitor_policies cc_monitor_policy;
	unsigned int cc_offer_timer;
	unsigned int ccnr_available_timer;
	unsigned int ccbs_available_timer;
	unsigned int cc_recall_timer;
	unsigned int cc_max_agents;
	unsigned int cc_max_monitors;
	char cc_callback_macro[AST_MAX_EXTENSION];
	char cc_callback_sub[AST_MAX_EXTENSION];
	char cc_agent_dialstring[AST_MAX_EXTENSION];
};

/*!
 * \since 1.8
 * \brief The states used in the CCSS core state machine
 *
 * For more information, see doc/CCSS_architecture.pdf
 */
enum cc_state {
	/*! Entered when it is determined that CCSS may be used for the call */
	CC_AVAILABLE,
	/*! Entered when a CCSS agent has offered CCSS to a caller */
	CC_CALLER_OFFERED,
	/*! Entered when a CCSS agent confirms that a caller has
	 * requested CCSS */
	CC_CALLER_REQUESTED,
	/*! Entered when a CCSS monitor confirms acknowledgment of an
	 * outbound CCSS request */
	CC_ACTIVE,
	/*! Entered when a CCSS monitor alerts the core that the called party
	 * has become available */
	CC_CALLEE_READY,
	/*! Entered when a CCSS agent alerts the core that the calling party
	 * may not be recalled because he is unavailable
	 */
	CC_CALLER_BUSY,
	/*! Entered when a CCSS agent alerts the core that the calling party
	 * is attempting to recall the called party
	 */
	CC_RECALLING,
	/*! Entered when an application alerts the core that the calling party's
	 * recall attempt has had a call progress response indicated
	 */
	CC_COMPLETE,
	/*! Entered any time that something goes wrong during the process, thus
	 * resulting in the failure of the attempted CCSS transaction. Note also
	 * that cancellations of CC are treated as failures.
	 */
	CC_FAILED,
};

/*!
 * \brief The payload for an AST_CONTROL_CC frame
 *
 * \details
 * This contains all the necessary data regarding
 * a called device so that the CC core will be able
 * to allocate the proper monitoring resources.
 */
struct cc_control_payload {
	/*!
	 * \brief The type of monitor to allocate.
	 *
	 * \details
	 * The type of monitor to allocate. This is a string which corresponds
	 * to a set of monitor callbacks registered. Examples include "generic"
	 * and "SIP"
	 *
	 * \note This really should be an array of characters in case this payload
	 * is sent accross an IAX2 link.  However, this would not make too much sense
	 * given this type may not be recognized by the other end.
	 * Protection may be necessary to prevent it from being transmitted.
	 *
	 * In addition the following other problems are also possible:
	 * 1) Endian issues with the integers/enums stored in the config_params.
	 * 2) Alignment padding issues for the element types.
	 */
	const char *monitor_type;
	/*!
	 * \brief Private data allocated by the callee
	 *
	 * \details
	 * All channel drivers that monitor endpoints will need to allocate
	 * data that is not usable by the CC core. In most cases, some or all
	 * of this data is allocated at the time that the channel driver offers
	 * CC to the caller. There are many opportunities for failures to occur
	 * between when a channel driver offers CC and when a monitor is actually
	 * allocated to watch the endpoint. For this reason, the channel driver
	 * must give the core a pointer to the private data that was allocated so
	 * that the core can call back into the channel driver to destroy it if
	 * a failure occurs. If no private data has been allocated at the time that
	 * CC is offered, then it is perfectly acceptable to pass NULL for this
	 * field.
	 */
	void *private_data;
	/*!
	 * \brief Service offered by the endpoint
	 *
	 * \details
	 * This indicates the type of call completion service offered by the
	 * endpoint. This data is not crucial to the machinations of the CC core,
	 * but it is helpful for debugging purposes.
	 */
	enum ast_cc_service_type service;
	/*!
	 * \brief Configuration parameters used by this endpoint
	 *
	 * \details
	 * Each time an endpoint offers call completion, it must provide its call
	 * completion configuration parameters. This is because settings may be different
	 * depending on the circumstances.
	 */
	struct ast_cc_config_params config_params;
	/*!
	 * \brief ID of parent extension
	 *
	 * \details
	 * This is the only datum that the CC core derives on its own and is not
	 * provided by the offerer of CC. This provides the core with information on
	 * which extension monitor is the most immediate parent of this device.
	 */
	int parent_interface_id;
	/*!
	 * \brief Name of device to be monitored
	 *
	 * \details
	 * The device name by which this monitored endpoint will be referred in the
	 * CC core. It is highly recommended that this device name is derived by using
	 * the function ast_channel_get_device_name.
	 */
	char device_name[AST_CHANNEL_NAME];
	/*!
	 * \brief Recall dialstring
	 *
	 * \details
	 * Certain channel drivers (DAHDI in particular) will require that a special
	 * dialstring be used to indicate that the outgoing call is to interpreted as
	 * a CC recall. If the channel driver has such a requirement, then this is
	 * where that special recall dialstring is placed. If no special dialstring
	 * is to be used, then the channel driver must provide the original dialstring
	 * used to call this endpoint.
	 */
	char dialstring[AST_CHANNEL_NAME];
};

/*!
 * \brief The "tree" of interfaces that is dialed.
 *
 * \details
 * Though this is a linked list, it is logically treated
 * as a tree of monitors. Each monitor has an id and a parent_id
 * associated with it. The id is a unique ID for that monitor, and
 * the parent_id is the unique ID of the monitor's parent in the
 * tree. The tree is structured such that all of a parent's children
 * will appear after the parent in the tree. However, it cannot be
 * guaranteed exactly where after the parent the children are.
 *
 * The tree is reference counted since several threads may need
 * to use it, and it may last beyond the lifetime of a single
 * thread.
 */
AST_LIST_HEAD(cc_monitor_tree, ast_cc_monitor);

static const int CC_CORE_INSTANCES_BUCKETS = 17;
static struct ao2_container *cc_core_instances;

struct cc_core_instance {
	/*!
	 * Unique identifier for this instance of the CC core.
	 */
	int core_id;
	/*!
	 * The current state for this instance of the CC core.
	 */
	enum cc_state current_state;
	/*!
	 * The CC agent in use for this call
	 */
	struct ast_cc_agent *agent;
	/*!
	 * Reference to the monitor tree formed during the initial call
	 */
	struct cc_monitor_tree *monitors;
};

/*!
 * \internal
 * \brief Request that the core change states
 * \param state The state to which we wish to change
 * \param core_id The unique identifier for this instance of the CCSS core state machine
 * \param debug Optional message explaining the reason for the state change
 * \param ap varargs list
 * \retval 0 State change successfully queued
 * \retval -1 Unable to queue state change request
 */
static int __attribute__((format(printf, 3, 0))) cc_request_state_change(enum cc_state state, const int core_id, const char *debug, va_list ap);

/*!
 * \internal
 * \brief create a new instance of the CC core and an agent for the calling channel
 *
 * This function will check to make sure that the incoming channel
 * is allowed to request CC by making sure that the incoming channel
 * has not exceeded its maximum number of allowed agents.
 *
 * Should that check pass, the core instance is created, and then the
 * agent for the channel.
 *
 * \param caller_chan The incoming channel for this particular call
 * \param called_tree A reference to the tree of called devices. The agent
 * will gain a reference to this tree as well
 * \param core_id The core_id that this core_instance will assume
 * \retval NULL Failed to create the core instance either due to memory allocation
 * errors or due to the agent count for the caller being too high
 * \retval non-NULL A reference to the newly created cc_core_instance
 */
static struct cc_core_instance *cc_core_init_instance(struct ast_channel *caller_chan,
		struct cc_monitor_tree *called_tree, const int core_id, struct cc_control_payload *cc_data);

static const struct {
	enum ast_cc_service_type service;
	const char *service_string;
} cc_service_to_string_map[] = {
	{AST_CC_NONE, "NONE"},
	{AST_CC_CCBS, "CCBS"},
	{AST_CC_CCNR, "CCNR"},
	{AST_CC_CCNL, "CCNL"},
};

static const struct {
	enum cc_state state;
	const char *state_string;
} cc_state_to_string_map[] = {
	{CC_AVAILABLE,          "CC is available"},
	{CC_CALLER_OFFERED,     "CC offered to caller"},
	{CC_CALLER_REQUESTED,   "CC requested by caller"},
	{CC_ACTIVE,             "CC accepted by callee"},
	{CC_CALLEE_READY,       "Callee has become available"},
	{CC_CALLER_BUSY,        "Callee was ready, but caller is now unavailable"},
	{CC_RECALLING,          "Caller is attempting to recall"},
	{CC_COMPLETE,           "Recall complete"},
	{CC_FAILED,             "CC has failed"},
};

static const char *cc_state_to_string(enum cc_state state)
{
	return cc_state_to_string_map[state].state_string;
}

static const char *cc_service_to_string(enum ast_cc_service_type service)
{
	return cc_service_to_string_map[service].service_string;
}

static int cc_core_instance_hash_fn(const void *obj, const int flags)
{
	const struct cc_core_instance *core_instance = obj;
	return core_instance->core_id;
}

static int cc_core_instance_cmp_fn(void *obj, void *arg, int flags)
{
	struct cc_core_instance *core_instance1 = obj;
	struct cc_core_instance *core_instance2 = arg;

	return core_instance1->core_id == core_instance2->core_id ? CMP_MATCH | CMP_STOP : 0;
}

static struct cc_core_instance *find_cc_core_instance(const int core_id)
{
	struct cc_core_instance finder = {.core_id = core_id,};

	return ao2_t_find(cc_core_instances, &finder, OBJ_POINTER, "Finding a core_instance");
}

struct cc_callback_helper {
	ao2_callback_fn *function;
	void *args;
	const char *type;
};

static int cc_agent_callback_helper(void *obj, void *args, int flags)
{
	struct cc_core_instance *core_instance = obj;
	struct cc_callback_helper *helper = args;

	if (strcmp(core_instance->agent->callbacks->type, helper->type)) {
		return 0;
	}

	return helper->function(core_instance->agent, helper->args, flags);
}

struct ast_cc_agent *ast_cc_agent_callback(int flags, ao2_callback_fn *function, void *args, const char * const type)
{
	struct cc_callback_helper helper = {.function = function, .args = args, .type = type};
	struct cc_core_instance *core_instance;
	if ((core_instance = ao2_t_callback(cc_core_instances, flags, cc_agent_callback_helper, &helper,
					"Calling provided agent callback function"))) {
		struct ast_cc_agent *agent = cc_ref(core_instance->agent, "An outside entity needs the agent");
		cc_unref(core_instance, "agent callback done with the core_instance");
		return agent;
	}
	return NULL;
}

enum match_flags {
	/* Only match agents that have not yet
	 * made a CC request
	 */
	MATCH_NO_REQUEST = (1 << 0),
	/* Only match agents that have made
	 * a CC request
	 */
	MATCH_REQUEST = (1 << 1),
};

/* ao2_callbacks for cc_core_instances */

/*!
 * \internal
 * \brief find a core instance based on its agent
 *
 * The match flags tell whether we wish to find core instances
 * that have a monitor or core instances that do not. Core instances
 * with no monitor are core instances for which a caller has not yet
 * requested CC. Core instances with a monitor are ones for which the
 * caller has requested CC.
 */
static int match_agent(void *obj, void *arg, void *data, int flags)
{
	struct cc_core_instance *core_instance = obj;
	const char *name = arg;
	unsigned long match_flags = *(unsigned long *)data;
	int possible_match = 0;

	if ((match_flags & MATCH_NO_REQUEST) && core_instance->current_state < CC_CALLER_REQUESTED) {
		possible_match = 1;
	}

	if ((match_flags & MATCH_REQUEST) && core_instance->current_state >= CC_CALLER_REQUESTED) {
		possible_match = 1;
	}

	if (!possible_match) {
		return 0;
	}

	if (!strcmp(core_instance->agent->device_name, name)) {
		return CMP_MATCH | CMP_STOP;
	}
	return 0;
}

struct count_agents_cb_data {
	int count;
	int core_id_exception;
};

/*!
 * \internal
 * \brief Count the number of agents a specific interface is using
 *
 * We're only concerned with the number of agents that have requested
 * CC, so we restrict our search to core instances which have a non-NULL
 * monitor pointer
 */
static int count_agents_cb(void *obj, void *arg, void *data, int flags)
{
	struct cc_core_instance *core_instance = obj;
	const char *name = arg;
	struct count_agents_cb_data *cb_data = data;

	if (cb_data->core_id_exception == core_instance->core_id) {
		ast_log_dynamic_level(cc_logger_level, "Found agent with core_id %d but not counting it toward total\n", core_instance->core_id);
		return 0;
	}

	if (core_instance->current_state >= CC_CALLER_REQUESTED && !strcmp(core_instance->agent->device_name, name)) {
		cb_data->count++;
	}
	return 0;
}

/* default values mapping from cc_state to ast_dev_state */

#define CC_AVAILABLE_DEVSTATE_DEFAULT        AST_DEVICE_NOT_INUSE
#define CC_CALLER_OFFERED_DEVSTATE_DEFAULT   AST_DEVICE_NOT_INUSE
#define CC_CALLER_REQUESTED_DEVSTATE_DEFAULT AST_DEVICE_NOT_INUSE
#define CC_ACTIVE_DEVSTATE_DEFAULT           AST_DEVICE_INUSE
#define CC_CALLEE_READY_DEVSTATE_DEFAULT     AST_DEVICE_RINGING
#define CC_CALLER_BUSY_DEVSTATE_DEFAULT      AST_DEVICE_ONHOLD
#define CC_RECALLING_DEVSTATE_DEFAULT        AST_DEVICE_RINGING
#define CC_COMPLETE_DEVSTATE_DEFAULT         AST_DEVICE_NOT_INUSE
#define CC_FAILED_DEVSTATE_DEFAULT           AST_DEVICE_NOT_INUSE

/*!
 * \internal
 * \brief initialization of defaults for CC_STATE to DEVICE_STATE map
 */
static enum ast_device_state cc_state_to_devstate_map[] = {
	[CC_AVAILABLE] =        CC_AVAILABLE_DEVSTATE_DEFAULT,
	[CC_CALLER_OFFERED] =   CC_CALLER_OFFERED_DEVSTATE_DEFAULT,
	[CC_CALLER_REQUESTED] = CC_CALLER_REQUESTED_DEVSTATE_DEFAULT,
	[CC_ACTIVE] =           CC_ACTIVE_DEVSTATE_DEFAULT,
	[CC_CALLEE_READY] =     CC_CALLEE_READY_DEVSTATE_DEFAULT,
	[CC_CALLER_BUSY] =      CC_CALLER_BUSY_DEVSTATE_DEFAULT,
	[CC_RECALLING] =        CC_RECALLING_DEVSTATE_DEFAULT,
	[CC_COMPLETE] =         CC_COMPLETE_DEVSTATE_DEFAULT,
	[CC_FAILED] =           CC_FAILED_DEVSTATE_DEFAULT,
};

/*!
 * \internal
 * \brief lookup the ast_device_state mapped to cc_state
 *
 * \param state
 *
 * \return the correponding DEVICE STATE from the cc_state_to_devstate_map
 * when passed an internal state.
 */
static enum ast_device_state cc_state_to_devstate(enum cc_state state)
{
	return cc_state_to_devstate_map[state];
}

/*!
 * \internal
 * \brief Callback for devicestate providers
 *
 * \details
 * Initialize with ast_devstate_prov_add() and returns the corresponding
 * DEVICE STATE based on the current CC_STATE state machine if the requested
 * device is found and is a generic device. Returns the equivalent of
 * CC_FAILED, which defaults to NOT_INUSE, if no device is found.  NOT_INUSE would
 * indicate that there is no presence of any pending call back.
 */
static enum ast_device_state ccss_device_state(const char *device_name)
{
	struct cc_core_instance *core_instance;
	unsigned long match_flags;
	enum ast_device_state cc_current_state;

	match_flags = MATCH_NO_REQUEST;
	core_instance = ao2_t_callback_data(cc_core_instances, 0, match_agent,
		(char *) device_name, &match_flags,
		"Find Core Instance for ccss_device_state reqeust.");
	if (!core_instance) {
		ast_log_dynamic_level(cc_logger_level,
			"Couldn't find a core instance for caller %s\n", device_name);
		return cc_state_to_devstate(CC_FAILED);
	}

	ast_log_dynamic_level(cc_logger_level,
		"Core %d: Found core_instance for caller %s in state %s\n",
		core_instance->core_id, device_name, cc_state_to_string(core_instance->current_state));

	if (strcmp(core_instance->agent->callbacks->type, "generic")) {
		ast_log_dynamic_level(cc_logger_level,
			"Core %d: Device State is only for generic agent types.\n",
			core_instance->core_id);
		cc_unref(core_instance, "Unref core_instance since ccss_device_state was called with native agent");
		return cc_state_to_devstate(CC_FAILED);
	}
	cc_current_state = cc_state_to_devstate(core_instance->current_state);
	cc_unref(core_instance, "Unref core_instance done with ccss_device_state");
	return cc_current_state;
}

/*!
 * \internal
 * \brief Notify Device State Changes from CC STATE MACHINE
 *
 * \details
 * Any time a state is changed, we call this function to notify the DEVICE STATE
 * subsystem of the change so that subscribed phones to any corresponding hints that
 * are using that state are updated.
 */
static void ccss_notify_device_state_change(const char *device, enum cc_state state)
{
	enum ast_device_state devstate;

	devstate = cc_state_to_devstate(state);

	ast_log_dynamic_level(cc_logger_level,
		"Notification of CCSS state change to '%s', device state '%s' for device '%s'\n",
		cc_state_to_string(state), ast_devstate2str(devstate), device);

	ast_devstate_changed(devstate, AST_DEVSTATE_CACHABLE, "ccss:%s", device);
}

#define CC_OFFER_TIMER_DEFAULT			20		/* Seconds */
#define CCNR_AVAILABLE_TIMER_DEFAULT	7200	/* Seconds */
#define CCBS_AVAILABLE_TIMER_DEFAULT	4800	/* Seconds */
#define CC_RECALL_TIMER_DEFAULT			20		/* Seconds */
#define CC_MAX_AGENTS_DEFAULT			5
#define CC_MAX_MONITORS_DEFAULT			5
#define GLOBAL_CC_MAX_REQUESTS_DEFAULT	20

static const struct ast_cc_config_params cc_default_params = {
	.cc_agent_policy = AST_CC_AGENT_NEVER,
	.cc_monitor_policy = AST_CC_MONITOR_NEVER,
	.cc_offer_timer = CC_OFFER_TIMER_DEFAULT,
	.ccnr_available_timer = CCNR_AVAILABLE_TIMER_DEFAULT,
	.ccbs_available_timer = CCBS_AVAILABLE_TIMER_DEFAULT,
	.cc_recall_timer = CC_RECALL_TIMER_DEFAULT,
	.cc_max_agents = CC_MAX_AGENTS_DEFAULT,
	.cc_max_monitors = CC_MAX_MONITORS_DEFAULT,
	.cc_callback_macro = "",
	.cc_callback_sub = "",
	.cc_agent_dialstring = "",
};

void ast_cc_default_config_params(struct ast_cc_config_params *params)
{
	*params = cc_default_params;
}

struct ast_cc_config_params *__ast_cc_config_params_init(const char *file, int line, const char *function)
{
	struct ast_cc_config_params *params = __ast_malloc(sizeof(*params), file, line, function);

	if (!params) {
		return NULL;
	}

	ast_cc_default_config_params(params);
	return params;
}

void ast_cc_config_params_destroy(struct ast_cc_config_params *params)
{
	ast_free(params);
}

static enum ast_cc_agent_policies str_to_agent_policy(const char * const value)
{
	if (!strcasecmp(value, "never")) {
		return AST_CC_AGENT_NEVER;
	} else if (!strcasecmp(value, "native")) {
		return AST_CC_AGENT_NATIVE;
	} else if (!strcasecmp(value, "generic")) {
		return AST_CC_AGENT_GENERIC;
	} else {
		ast_log(LOG_WARNING, "%s is an invalid value for cc_agent_policy. Switching to 'never'\n", value);
		return AST_CC_AGENT_NEVER;
	}
}

static enum ast_cc_monitor_policies str_to_monitor_policy(const char * const value)
{
	if (!strcasecmp(value, "never")) {
		return AST_CC_MONITOR_NEVER;
	} else if (!strcasecmp(value, "native")) {
		return AST_CC_MONITOR_NATIVE;
	} else if (!strcasecmp(value, "generic")) {
		return AST_CC_MONITOR_GENERIC;
	} else if (!strcasecmp(value, "always")) {
		return AST_CC_MONITOR_ALWAYS;
	} else {
		ast_log(LOG_WARNING, "%s is an invalid value for cc_monitor_policy. Switching to 'never'\n", value);
		return AST_CC_MONITOR_NEVER;
	}
}

static const char *agent_policy_to_str(enum ast_cc_agent_policies policy)
{
	switch (policy) {
	case AST_CC_AGENT_NEVER:
		return "never";
	case AST_CC_AGENT_NATIVE:
		return "native";
	case AST_CC_AGENT_GENERIC:
		return "generic";
	default:
		/* This should never happen... */
		return "";
	}
}

static const char *monitor_policy_to_str(enum ast_cc_monitor_policies policy)
{
	switch (policy) {
	case AST_CC_MONITOR_NEVER:
		return "never";
	case AST_CC_MONITOR_NATIVE:
		return "native";
	case AST_CC_MONITOR_GENERIC:
		return "generic";
	case AST_CC_MONITOR_ALWAYS:
		return "always";
	default:
		/* This should never happen... */
		return "";
	}
}
int ast_cc_get_param(struct ast_cc_config_params *params, const char * const name,
		char *buf, size_t buf_len)
{
	const char *value = NULL;

	if (!strcasecmp(name, "cc_callback_macro")) {
		value = ast_get_cc_callback_macro(params);
	} else if (!strcasecmp(name, "cc_callback_sub")) {
		value = ast_get_cc_callback_sub(params);
	} else if (!strcasecmp(name, "cc_agent_policy")) {
		value = agent_policy_to_str(ast_get_cc_agent_policy(params));
	} else if (!strcasecmp(name, "cc_monitor_policy")) {
		value = monitor_policy_to_str(ast_get_cc_monitor_policy(params));
	} else if (!strcasecmp(name, "cc_agent_dialstring")) {
		value = ast_get_cc_agent_dialstring(params);
	}
	if (value) {
		ast_copy_string(buf, value, buf_len);
		return 0;
	}

	/* The rest of these are all ints of some sort and require some
	 * snprintf-itude
	 */

	if (!strcasecmp(name, "cc_offer_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_offer_timer(params));
	} else if (!strcasecmp(name, "ccnr_available_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_ccnr_available_timer(params));
	} else if (!strcasecmp(name, "ccbs_available_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_ccbs_available_timer(params));
	} else if (!strcasecmp(name, "cc_max_agents")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_max_agents(params));
	} else if (!strcasecmp(name, "cc_max_monitors")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_max_monitors(params));
	} else if (!strcasecmp(name, "cc_recall_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_recall_timer(params));
	} else {
		ast_log(LOG_WARNING, "%s is not a valid CC parameter. Ignoring.\n", name);
		return -1;
	}

	return 0;
}

int ast_cc_set_param(struct ast_cc_config_params *params, const char * const name,
		const char * const value)
{
	unsigned int value_as_uint;
	if (!strcasecmp(name, "cc_agent_policy")) {
		return ast_set_cc_agent_policy(params, str_to_agent_policy(value));
	} else if (!strcasecmp(name, "cc_monitor_policy")) {
		return ast_set_cc_monitor_policy(params, str_to_monitor_policy(value));
	} else if (!strcasecmp(name, "cc_agent_dialstring")) {
		ast_set_cc_agent_dialstring(params, value);
	} else if (!strcasecmp(name, "cc_callback_macro")) {
		ast_set_cc_callback_macro(params, value);
		return 0;
	} else if (!strcasecmp(name, "cc_callback_sub")) {
		ast_set_cc_callback_sub(params, value);
		return 0;
	}

	if (sscanf(value, "%30u", &value_as_uint) != 1) {
		return -1;
	}

	if (!strcasecmp(name, "cc_offer_timer")) {
		ast_set_cc_offer_timer(params, value_as_uint);
	} else if (!strcasecmp(name, "ccnr_available_timer")) {
		ast_set_ccnr_available_timer(params, value_as_uint);
	} else if (!strcasecmp(name, "ccbs_available_timer")) {
		ast_set_ccbs_available_timer(params, value_as_uint);
	} else if (!strcasecmp(name, "cc_max_agents")) {
		ast_set_cc_max_agents(params, value_as_uint);
	} else if (!strcasecmp(name, "cc_max_monitors")) {
		ast_set_cc_max_monitors(params, value_as_uint);
	} else if (!strcasecmp(name, "cc_recall_timer")) {
		ast_set_cc_recall_timer(params, value_as_uint);
	} else {
		ast_log(LOG_WARNING, "%s is not a valid CC parameter. Ignoring.\n", name);
		return -1;
	}

	return 0;
}

int ast_cc_is_config_param(const char * const name)
{
	return (!strcasecmp(name, "cc_agent_policy") ||
				!strcasecmp(name, "cc_monitor_policy") ||
				!strcasecmp(name, "cc_offer_timer") ||
				!strcasecmp(name, "ccnr_available_timer") ||
				!strcasecmp(name, "ccbs_available_timer") ||
				!strcasecmp(name, "cc_max_agents") ||
				!strcasecmp(name, "cc_max_monitors") ||
				!strcasecmp(name, "cc_callback_macro") ||
				!strcasecmp(name, "cc_callback_sub") ||
				!strcasecmp(name, "cc_agent_dialstring") ||
				!strcasecmp(name, "cc_recall_timer"));
}

void ast_cc_copy_config_params(struct ast_cc_config_params *dest, const struct ast_cc_config_params *src)
{
	*dest = *src;
}

enum ast_cc_agent_policies ast_get_cc_agent_policy(struct ast_cc_config_params *config)
{
	return config->cc_agent_policy;
}

int ast_set_cc_agent_policy(struct ast_cc_config_params *config, enum ast_cc_agent_policies value)
{
	/* Screw C and its weak type checking for making me have to do this
	 * validation at runtime.
	 */
	if (value < AST_CC_AGENT_NEVER || value > AST_CC_AGENT_GENERIC) {
		return -1;
	}
	config->cc_agent_policy = value;
	return 0;
}

enum ast_cc_monitor_policies ast_get_cc_monitor_policy(struct ast_cc_config_params *config)
{
	return config->cc_monitor_policy;
}

int ast_set_cc_monitor_policy(struct ast_cc_config_params *config, enum ast_cc_monitor_policies value)
{
	/* Screw C and its weak type checking for making me have to do this
	 * validation at runtime.
	 */
	if (value < AST_CC_MONITOR_NEVER || value > AST_CC_MONITOR_ALWAYS) {
		return -1;
	}
	config->cc_monitor_policy = value;
	return 0;
}

unsigned int ast_get_cc_offer_timer(struct ast_cc_config_params *config)
{
	return config->cc_offer_timer;
}

void ast_set_cc_offer_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for cc_offer_timer. Retaining value as %u\n", config->cc_offer_timer);
		return;
	}
	config->cc_offer_timer = value;
}

unsigned int ast_get_ccnr_available_timer(struct ast_cc_config_params *config)
{
	return config->ccnr_available_timer;
}

void ast_set_ccnr_available_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for ccnr_available_timer. Retaining value as %u\n", config->ccnr_available_timer);
		return;
	}
	config->ccnr_available_timer = value;
}

unsigned int ast_get_cc_recall_timer(struct ast_cc_config_params *config)
{
	return config->cc_recall_timer;
}

void ast_set_cc_recall_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for ccnr_available_timer. Retaining value as %u\n", config->cc_recall_timer);
		return;
	}
	config->cc_recall_timer = value;
}

unsigned int ast_get_ccbs_available_timer(struct ast_cc_config_params *config)
{
	return config->ccbs_available_timer;
}

void ast_set_ccbs_available_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for ccbs_available_timer. Retaining value as %u\n", config->ccbs_available_timer);
		return;
	}
	config->ccbs_available_timer = value;
}

const char *ast_get_cc_agent_dialstring(struct ast_cc_config_params *config)
{
	return config->cc_agent_dialstring;
}

void ast_set_cc_agent_dialstring(struct ast_cc_config_params *config, const char *const value)
{
	if (ast_strlen_zero(value)) {
		config->cc_agent_dialstring[0] = '\0';
	} else {
		ast_copy_string(config->cc_agent_dialstring, value, sizeof(config->cc_agent_dialstring));
	}
}

unsigned int ast_get_cc_max_agents(struct ast_cc_config_params *config)
{
	return config->cc_max_agents;
}

void ast_set_cc_max_agents(struct ast_cc_config_params *config, unsigned int value)
{
	config->cc_max_agents = value;
}

unsigned int ast_get_cc_max_monitors(struct ast_cc_config_params *config)
{
	return config->cc_max_monitors;
}

void ast_set_cc_max_monitors(struct ast_cc_config_params *config, unsigned int value)
{
	config->cc_max_monitors = value;
}

const char *ast_get_cc_callback_macro(struct ast_cc_config_params *config)
{
	return config->cc_callback_macro;
}

const char *ast_get_cc_callback_sub(struct ast_cc_config_params *config)
{