path: root/src/libosmocc/message.c

/* Osmo-CC: Message handling
 *
 * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
 * All Rights Reserved
 *
 * 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 3 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include "../libdebug/debug.h"
#include "message.h"

static uint32_t new_callref = 0;

uint32_t osmo_cc_new_callref(void)
{
	return (++new_callref);
}

const char *osmo_cc_msg_name(uint8_t msg_type)
{
	switch (msg_type) {
	case OSMO_CC_MSG_SETUP_REQ:
		return "CC-SETUP-REQ";
	case OSMO_CC_MSG_SETUP_IND:
		return "CC-SETUP-IND";
	case OSMO_CC_MSG_REJ_REQ:
		return "CC-REJ-REQ";
	case OSMO_CC_MSG_REJ_IND:
		return "CC-REJ-IND";
	case OSMO_CC_MSG_SETUP_ACK_REQ:
		return "CC-SETUP-ACK-REQ";
	case OSMO_CC_MSG_SETUP_ACK_IND:
		return "CC-SETUP-ACK-IND";
	case OSMO_CC_MSG_PROC_REQ:
		return "CC-PROC-REQ";
	case OSMO_CC_MSG_PROC_IND:
		return "CC-PROC-IND";
	case OSMO_CC_MSG_ALERT_REQ:
		return "CC-ALERT-REQ";
	case OSMO_CC_MSG_ALERT_IND:
		return "CC-ALERT-IND";
	case OSMO_CC_MSG_SETUP_RSP:
		return "CC-SETUP-RSP";
	case OSMO_CC_MSG_SETUP_CNF:
		return "CC-SETUP-CNF";
	case OSMO_CC_MSG_SETUP_COMP_REQ:
		return "CC-SETUP-COMP-REQ";
	case OSMO_CC_MSG_SETUP_COMP_IND:
		return "CC-SETUP-COMP-IND";
	case OSMO_CC_MSG_DISC_REQ:
		return "CC-DISC-REQ";
	case OSMO_CC_MSG_DISC_IND:
		return "CC-DISC-IND";
	case OSMO_CC_MSG_REL_REQ:
		return "CC-REL-REQ";
	case OSMO_CC_MSG_REL_CNF:
		return "CC-REL-CNF";
	case OSMO_CC_MSG_REL_IND:
		return "CC-REL-IND";
	case OSMO_CC_MSG_PROGRESS_REQ:
		return "CC-PROGRESS-REQ";
	case OSMO_CC_MSG_PROGRESS_IND:
		return "CC-PROGRESS-IND";
	case OSMO_CC_MSG_NOTIFY_REQ:
		return "CC-NOTIFY-REQ";
	case OSMO_CC_MSG_NOTIFY_IND:
		return "CC-NOTIFY-IND";
	case OSMO_CC_MSG_INFO_REQ:
		return "CC-INFO-REQ";
	case OSMO_CC_MSG_INFO_IND:
		return "CC-INFO-IND";
	case OSMO_CC_MSG_ATTACH_REQ:
		return "CC-ATTACH-REQ";
	case OSMO_CC_MSG_ATTACH_IND:
		return "CC-ATTACH-IND";
	case OSMO_CC_MSG_ATTACH_RSP:
		return "CC-ATTACH-RSP";
	case OSMO_CC_MSG_ATTACH_CNF:
		return "CC-ATTACH-CNF";
	default:
		return "<unknown>";
	}
}

/* create message with maximum size */
osmo_cc_msg_t *osmo_cc_new_msg(uint8_t msg_type)
{
	osmo_cc_msg_t *msg;

	/* allocate message */
	msg = calloc(1, sizeof(*msg) + 65535);
	if (!msg) {
		PDEBUG(DCC, DEBUG_ERROR, "No memory\n");
		abort();
	}
	/* set message type and zero lentgh */
	msg->type = msg_type;
	msg->length_networkorder = htons(0);

	return msg;
}

/* clone message */
osmo_cc_msg_t *osmo_cc_clone_msg(osmo_cc_msg_t *msg)
{
	osmo_cc_msg_t *new_msg;

	new_msg = osmo_cc_new_msg(msg->type);
	new_msg->length_networkorder = msg->length_networkorder;
	memcpy(new_msg->data, msg->data, ntohs(msg->length_networkorder));

	return new_msg;
}

osmo_cc_msg_t *osmo_cc_msg_list_dequeue(osmo_cc_msg_list_t **mlp, uint32_t *callref_p)
{
	osmo_cc_msg_list_t *ml;
	osmo_cc_msg_t *msg;

	ml = *mlp;
	msg = ml->msg;
	if (callref_p)
		*callref_p = ml->callref;
	*mlp = ml->next;
	free(ml);

	return msg;
}

osmo_cc_msg_list_t *osmo_cc_msg_list_enqueue(osmo_cc_msg_list_t **mlp, osmo_cc_msg_t *msg, uint32_t callref)
{
	osmo_cc_msg_list_t *ml;

	ml = calloc(1, sizeof(*ml));
	ml->msg = msg;
	ml->callref = callref;
	while (*mlp)
		mlp = &((*mlp)->next);
	*mlp = ml;

	return ml;
}

/* destroy message */
void osmo_cc_free_msg(osmo_cc_msg_t *msg)
{
	free(msg);
}

static void osmo_cc_debug_ie(osmo_cc_msg_t *msg, int level)
{
	uint16_t msg_len, len;
	uint8_t *p;
	osmo_cc_ie_t *ie;

	msg_len = ntohs(msg->length_networkorder);
	p = msg->data;

	PDEBUG(DCC, level, "Debugging Message: type=0x%02x length=%d value=%s\n", msg->type, msg_len, debug_hex(p, msg_len));
	while (msg_len) {
		ie = (osmo_cc_ie_t *)p;
		/* check for minimum IE length */
		if (msg_len < sizeof(*ie)) {
			PDEBUG(DCC, level, "****** Rest of message is too short for an IE: value=%s\n", debug_hex(p, msg_len));
			return;
		}
		/* get actual IE length */
		len = ntohs(ie->length_networkorder);
		/* check if IE length does not exceed message */
		if (msg_len < sizeof(*ie) + len) {
			PDEBUG(DCC, level, "****** IE: type=0x%02x length=%d would exceed the rest length of message (%d bytes left)\n", ie->type, len, msg_len - (int)sizeof(*ie));
			return;
		}
		PDEBUG(DCC, level, "IE: type=0x%02x length=%d value=%s\n", ie->type, len, debug_hex(ie->data, len));
		p += sizeof(*ie) + len;
		msg_len -= sizeof(*ie) + len;
	}
}

/* search and return information element
 * we give the IE type we are searching for
 * we also give the repetition, to find IE that is repeated
 * the result is stored in *ie_data
 * the return length is the length that exceeds the given ie_len
 * if there is an error, a value < 0 is returned
 */
int osmo_cc_get_ie_struct(osmo_cc_msg_t *msg, uint8_t ie_type, int ie_repeat, int ie_len, const osmo_cc_ie_t **ie_struct)
{
	uint16_t msg_len, len;
	uint8_t *p;
	osmo_cc_ie_t *ie;

	msg_len = ntohs(msg->length_networkorder);
	p = msg->data;

	while (msg_len) {
		ie = (osmo_cc_ie_t *)p;
		/* check for minimum IE length */
		if (msg_len < sizeof(*ie)) {
			PDEBUG(DCC, DEBUG_ERROR, "MSG short read\n");
			osmo_cc_debug_ie(msg, DEBUG_ERROR);
			return -EINVAL;
		}
		/* get actual IE length */
		len = ntohs(ie->length_networkorder);
		/* check if IE length does not exceed message */
		if (msg_len < sizeof(*ie) + len) {
			PDEBUG(DCC, DEBUG_ERROR, "MSG short read\n");
			osmo_cc_debug_ie(msg, DEBUG_ERROR);
			return -EINVAL;
		}
		/* check if IE matches the one that is searched for */
		if (ie->type != ie_type) {
			p += sizeof(*ie) + len;
			msg_len -= sizeof(*ie) + len;
			continue;
		}
		/* check if IE repetition exists */
		if (ie_repeat) {
			--ie_repeat;
			p += sizeof(*ie) + len;
			msg_len -= sizeof(*ie) + len;
			continue;
		}
		/* return IE and indicate how many bytes we have more than the given length*/
		if (ntohs(ie->length_networkorder) < ie_len) {
			PDEBUG(DCC, DEBUG_ERROR, "IE 0x%02d has length of %d, but we expect it to have at least %d!\n", ie_type, ntohs(ie->length_networkorder), ie_len);
			return -EINVAL;
		}
		*ie_struct = ie;
		return ntohs(ie->length_networkorder) - ie_len;
	}

	/* IE not found */
	return -EINVAL;
}

/* as above, but return data of IE only */
int osmo_cc_get_ie_data(osmo_cc_msg_t *msg, uint8_t ie_type, int ie_repeat, int ie_len, const void **ie_data)
{
	const osmo_cc_ie_t *ie;
	int rc;

	rc = osmo_cc_get_ie_struct(msg, ie_type, ie_repeat, ie_len, &ie);
	if (rc >= 0)
		*ie_data = ie->data;

	return rc;
}

/* as above, but return 1 if IE exists */
int osmo_cc_has_ie(osmo_cc_msg_t *msg, uint8_t ie_type, int ie_repeat)
{
	const osmo_cc_ie_t *ie;
	int rc;

	rc = osmo_cc_get_ie_struct(msg, ie_type, ie_repeat, 0, &ie);
	if (rc >= 0)
		return 1;

	return 0;
}

/* remove IE from message */
int osmo_cc_remove_ie(osmo_cc_msg_t *msg, uint8_t ie_type, int ie_repeat)
{
	const osmo_cc_ie_t *ie;
	int rc;
	int msg_len, before_ie, ie_size, after_ie;

	rc = osmo_cc_get_ie_struct(msg, ie_type, ie_repeat, 0, &ie);
	if (rc < 0)
		return rc;

	msg_len = ntohs(msg->length_networkorder);
	before_ie = (void *)ie - (void *)msg->data;
	ie_size = sizeof(*ie) + ntohs(ie->length_networkorder);
	after_ie = msg_len - ie_size - before_ie;
	if (after_ie)
		memcpy(msg->data + before_ie, msg->data + before_ie + ie_size, after_ie);
	msg->length_networkorder = htons(msg_len - ie_size);

	return 0;
}

/* add information element
 * the type is given by ie_type and length is given by ie_len
 * the return value is a pointer to the data of the IE
 */
void *osmo_cc_add_ie(osmo_cc_msg_t *msg, uint8_t ie_type, int ie_len)
{
	uint16_t msg_len;
	int new_msg_len;
	uint8_t *p;
	osmo_cc_ie_t *ie;

	/* get pointer to first IE, if any */
	p = msg->data;
	/* expand messasge */
	msg_len = ntohs(msg->length_networkorder);
	new_msg_len = msg_len + sizeof(*ie) + ie_len;
	if (new_msg_len > 65535) {
		PDEBUG(DCC, DEBUG_ERROR, "MSG overflow\n");
		return NULL;
	}
	msg->length_networkorder = htons(new_msg_len);
	/* go to end of (unexpanded) message */
	ie = (osmo_cc_ie_t *)(p + msg_len);
	/* add ie */
	ie->type = ie_type;
	ie->length_networkorder = htons(ie_len);
	memset(ie->data, 0, ie_len); /* just in case there is something, but it shouldn't */

	return ie->data;
}

/* gets the information element's data that *iep points to and returns that ie.
 * if *iep points to msg->data, the first IE's data is returned. (must be set before first call.)
 * if *iep points to the end of the message, NULL is returned.
 * if there is no next IE, *iep is set to point to the end of message.
 */
void *osmo_cc_msg_sep_ie(osmo_cc_msg_t *msg, void **iep, uint8_t *ie_type, uint16_t *ie_length)
{
	uint16_t msg_len;
	osmo_cc_ie_t *ie;

	/* in case that *iep points to start of message, make it point to first IE */
	if (*iep == msg)
		*iep = msg->data;
	/* case IE */
	ie = *iep;
	/* check if it is NULL */
	if (ie == NULL)
		return NULL;
	/* check if it points to the end of message or there is not at least an IE header */
	msg_len = ntohs(msg->length_networkorder);
	if ((int)((uint8_t *)ie - msg->data) > (int)(msg_len - sizeof(*ie)))
		return NULL;
	/* increment iep and return IE */
	*ie_type = ie->type;
	*ie_length = ntohs(ie->length_networkorder);
	*iep = (uint8_t *)ie + sizeof(*ie) + *ie_length;
	return ie->data;
}

/* copy given block to given string with given size */
static void _ie2string(char *string, size_t string_size, const char *ie_string, int ie_size)
{
	int copy_size;

	copy_size = string_size - 1;
	if (ie_size < copy_size)
		copy_size = ie_size;
	memcpy(string, ie_string, copy_size);
	string[copy_size] = '\0';
}

/* helper to encode called party number (dialing) */
void osmo_cc_add_ie_called(osmo_cc_msg_t *msg, uint8_t type, uint8_t plan, const char *dialing)
{
	struct osmo_cc_ie_called *ie_called;

	ie_called = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLED, sizeof(*ie_called) + strlen(dialing));
	ie_called->type = type;
	ie_called->plan = plan;
	memcpy(ie_called->digits, dialing, strlen(dialing));
}

/* helper to decode called party number (dialing) */
int osmo_cc_get_ie_called(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *type, uint8_t *plan, char *dialing, size_t dialing_size)
{
	struct osmo_cc_ie_called *ie_called;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLED, ie_repeat, sizeof(*ie_called), (const void **)&ie_called);
	if (rc < 0)
		return rc;
	*type = ie_called->type;
	*plan = ie_called->plan;
	_ie2string(dialing, dialing_size, ie_called->digits, rc);
	return rc;
}

/* helper to encode called party sub address (dialing) */
void osmo_cc_add_ie_called_sub(osmo_cc_msg_t *msg, uint8_t type, const char *dialing)
{
	struct osmo_cc_ie_called_sub *ie_called_sub;

	ie_called_sub = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLED_SUB, sizeof(*ie_called_sub) + strlen(dialing));
	ie_called_sub->type = type;
	memcpy(ie_called_sub->digits, dialing, strlen(dialing));
}

/* helper to decode called party sub address (dialing) */
int osmo_cc_get_ie_called_sub(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *type, char *dialing, size_t dialing_size)
{
	struct osmo_cc_ie_called_sub *ie_called_sub;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLED_SUB, ie_repeat, sizeof(*ie_called_sub), (const void **)&ie_called_sub);
	if (rc < 0)
		return rc;
	*type = ie_called_sub->type;
	_ie2string(dialing, dialing_size, ie_called_sub->digits, rc);
	return rc;
}

/* helper to encode called party name (dialing) */
void osmo_cc_add_ie_called_name(osmo_cc_msg_t *msg, const char *name)
{
	struct osmo_cc_ie_called_name *ie_called_name;

	ie_called_name = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLED_NAME, sizeof(*ie_called_name) + strlen(name));
	memcpy(ie_called_name->name, name, strlen(name));
}

/* helper to decode called party name (dialing) */
int osmo_cc_get_ie_called_name(osmo_cc_msg_t *msg, int ie_repeat, char *name, size_t name_size)
{
	struct osmo_cc_ie_called_name *ie_called_name;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLED_NAME, ie_repeat, sizeof(*ie_called_name), (const void **)&ie_called_name);
	if (rc < 0)
		return rc;
	_ie2string(name, name_size, ie_called_name->name, rc);
	return rc;
}

/* helper to encode called interface name */
void osmo_cc_add_ie_called_interface(osmo_cc_msg_t *msg, const char *interface)
{
	struct osmo_cc_ie_called_interface *ie_interface;

	ie_interface = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLED_INTERFACE, sizeof(*ie_interface) + strlen(interface));
	memcpy(ie_interface->name, interface, strlen(interface));
}

/* helper to decode called interface name */
int osmo_cc_get_ie_called_interface(osmo_cc_msg_t *msg, int ie_repeat, char *interface, size_t interface_size)
{
	struct osmo_cc_ie_called_interface *ie_interface;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLED_INTERFACE, ie_repeat, sizeof(*ie_interface), (const void **)&ie_interface);
	if (rc < 0)
		return rc;
	_ie2string(interface, interface_size, ie_interface->name, rc);
	return rc;
}

/* helper to encode complete IE */
void osmo_cc_add_ie_complete(osmo_cc_msg_t *msg)
{
	osmo_cc_add_ie(msg, OSMO_CC_IE_COMPLETE, 0);
}

/* helper to decode complete IE */
int osmo_cc_get_ie_complete(osmo_cc_msg_t *msg, int ie_repeat)
{
	int rc;
	void *ie_complete;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_COMPLETE, ie_repeat, 0, (const void **)&ie_complete);
	return rc;
}

/* helper to encode calling/connected party number (caller ID or connected ID) */
void osmo_cc_add_ie_calling(osmo_cc_msg_t *msg, uint8_t type, uint8_t plan, uint8_t present, uint8_t screen, const char *callerid)
{
	struct osmo_cc_ie_calling *ie_calling;

	ie_calling = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLING, sizeof(*ie_calling) + strlen(callerid));
	ie_calling->type = type;
	ie_calling->plan = plan;
	ie_calling->present = present;
	ie_calling->screen = screen;
	memcpy(ie_calling->digits, callerid, strlen(callerid));
}

/* helper to decode calling/connected party number (caller ID or connected ID) */
int osmo_cc_get_ie_calling(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *type, uint8_t *plan, uint8_t *present, uint8_t *screen, char *callerid, size_t callerid_size)
{
	struct osmo_cc_ie_calling *ie_calling;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLING, ie_repeat, sizeof(*ie_calling), (const void **)&ie_calling);
	if (rc < 0)
		return rc;
	*type = ie_calling->type;
	*plan = ie_calling->plan;
	*present = ie_calling->present;
	*screen = ie_calling->screen;
	_ie2string(callerid, callerid_size, ie_calling->digits, rc);
	return rc;
}

/* helper to encode calling/connected sub address (caller ID or connected ID) */
void osmo_cc_add_ie_calling_sub(osmo_cc_msg_t *msg, uint8_t type, const char *callerid)
{
	struct osmo_cc_ie_calling_sub *ie_calling_sub;

	ie_calling_sub = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLING_SUB, sizeof(*ie_calling_sub) + strlen(callerid));
	ie_calling_sub->type = type;
	memcpy(ie_calling_sub->digits, callerid, strlen(callerid));
}

/* helper to decode calling/connected sub address (caller ID or connected ID) */
int osmo_cc_get_ie_calling_sub(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *type, char *callerid, size_t callerid_size)
{
	struct osmo_cc_ie_calling_sub *ie_calling_sub;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLING_SUB, ie_repeat, sizeof(*ie_calling_sub), (const void **)&ie_calling_sub);
	if (rc < 0)
		return rc;
	*type = ie_calling_sub->type;
	_ie2string(callerid, callerid_size, ie_calling_sub->digits, rc);
	return rc;
}

/* helper to encode calling/connected name (caller ID or connected ID) */
void osmo_cc_add_ie_calling_name(osmo_cc_msg_t *msg, const char *name)
{
	struct osmo_cc_ie_calling_name *ie_calling_name;

	ie_calling_name = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLING_NAME, sizeof(*ie_calling_name) + strlen(name));
	memcpy(ie_calling_name->name, name, strlen(name));
}

/* helper to decode calling/connected name address (caller ID or connected ID) */
int osmo_cc_get_ie_calling_name(osmo_cc_msg_t *msg, int ie_repeat, char *name, size_t name_size)
{
	struct osmo_cc_ie_calling_name *ie_calling_name;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLING_NAME, ie_repeat, sizeof(*ie_calling_name), (const void **)&ie_calling_name);
	if (rc < 0)
		return rc;
	_ie2string(name, name_size, ie_calling_name->name, rc);
	return rc;
}

/* helper to encode calling interface name */
void osmo_cc_add_ie_calling_interface(osmo_cc_msg_t *msg, const char *interface)
{
	struct osmo_cc_ie_calling_interface *ie_interface;

	ie_interface = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLING_INTERFACE, sizeof(*ie_interface) + strlen(interface));
	memcpy(ie_interface->name, interface, strlen(interface));
}

/* helper to decode calling interface name */
int osmo_cc_get_ie_calling_interface(osmo_cc_msg_t *msg, int ie_repeat, char *interface, size_t interface_size)
{
	struct osmo_cc_ie_calling_interface *ie_interface;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLING_INTERFACE, ie_repeat, sizeof(*ie_interface), (const void **)&ie_interface);
	if (rc < 0)
		return rc;
	_ie2string(interface, interface_size, ie_interface->name, rc);
	return rc;
}

/* helper to encode network specific caller/connected ID */
void osmo_cc_add_ie_calling_network(osmo_cc_msg_t *msg, uint8_t type, const char *networkid)
{
	struct osmo_cc_ie_network *ie_network;

	ie_network = osmo_cc_add_ie(msg, OSMO_CC_IE_CALLING_NETWORK, sizeof(*ie_network) + strlen(networkid));
	ie_network->type = type;
	memcpy(ie_network->id, networkid, strlen(networkid));
}

/* helper to encode network specific caller/connected ID */
int osmo_cc_get_ie_calling_network(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *type, char *networkid, size_t networkid_size)
{
	struct osmo_cc_ie_network *ie_network;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CALLING_NETWORK, ie_repeat, sizeof(*ie_network), (const void **)&ie_network);
	if (rc < 0)
		return rc;
	*type = ie_network->type;
	_ie2string(networkid, networkid_size, ie_network->id, rc);
	return rc;
}

/* helper to encode bearer capability */
void osmo_cc_add_ie_bearer(osmo_cc_msg_t *msg, uint8_t coding, uint8_t capability, uint8_t mode)
{
	struct osmo_cc_ie_bearer *ie_bearer;

	ie_bearer = osmo_cc_add_ie(msg, OSMO_CC_IE_BEARER, sizeof(*ie_bearer));
	ie_bearer->coding = coding;
	ie_bearer->capability = capability;
	ie_bearer->mode = mode;
}

/* helper to decode bearer capability */
int osmo_cc_get_ie_bearer(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *coding, uint8_t *capability, uint8_t *mode)
{
	struct osmo_cc_ie_bearer *ie_bearer;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_BEARER, ie_repeat, sizeof(*ie_bearer), (const void **)&ie_bearer);
	if (rc < 0)
		return rc;
	*coding = ie_bearer->coding;
	*capability = ie_bearer->capability;
	*mode = ie_bearer->mode;
	return rc;
}

/* helper to encode redirection and redirecting number */
void osmo_cc_add_ie_redir(osmo_cc_msg_t *msg, uint8_t type, uint8_t plan, uint8_t present, uint8_t screen, uint8_t redir_reason, const char *callerid)
{
	struct osmo_cc_ie_redir *ie_redir;

	ie_redir = osmo_cc_add_ie(msg, OSMO_CC_IE_REDIR, sizeof(*ie_redir) + strlen(callerid));
	ie_redir->type = type;
	ie_redir->plan = plan;
	ie_redir->present = present;
	ie_redir->screen = screen;
	ie_redir->redir_reason = redir_reason;
	memcpy(ie_redir->digits, callerid, strlen(callerid));
}

/* helper to decode redirection and redirecting number */
int osmo_cc_get_ie_redir(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *type, uint8_t *plan, uint8_t *present, uint8_t *screen, uint8_t *reason, char *callerid, size_t callerid_size)
{
	struct osmo_cc_ie_redir *ie_redir;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_REDIR, ie_repeat, sizeof(*ie_redir), (const void **)&ie_redir);
	if (rc < 0)
		return rc;
	*type = ie_redir->type;
	*plan = ie_redir->plan;
	*present = ie_redir->present;
	*screen = ie_redir->screen;
	*reason = ie_redir->redir_reason;
	_ie2string(callerid, callerid_size, ie_redir->digits, rc);
	return rc;
}

/* helper to encode DTMF tones */
void osmo_cc_add_ie_dtmf(osmo_cc_msg_t *msg, uint8_t duration_ms, uint8_t pause_ms, uint8_t dtmf_mode, const char *digits)
{
	struct osmo_cc_ie_dtmf *ie_dtmf;

	ie_dtmf = osmo_cc_add_ie(msg, OSMO_CC_IE_DTMF, sizeof(*ie_dtmf) + strlen(digits));
	ie_dtmf->duration_ms = duration_ms;
	ie_dtmf->pause_ms = pause_ms;
	ie_dtmf->dtmf_mode = dtmf_mode;
	memcpy(ie_dtmf->digits, digits, strlen(digits));
}

/* helper to decode DTMF tones */
int osmo_cc_get_ie_dtmf(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *duration_ms, uint8_t *pause_ms, uint8_t *dtmf_mode, char *digits, size_t digits_size)
{
	struct osmo_cc_ie_dtmf *ie_dtmf;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_DTMF, ie_repeat, sizeof(*ie_dtmf), (const void **)&ie_dtmf);
	if (rc < 0)
		return rc;
	*duration_ms = ie_dtmf->duration_ms;
	*pause_ms = ie_dtmf->pause_ms;
	*dtmf_mode = ie_dtmf->dtmf_mode;
	_ie2string(digits, digits_size, ie_dtmf->digits, rc);
	return rc;
}

/* helper to encode keypad press */
void osmo_cc_add_ie_keypad(osmo_cc_msg_t *msg, const char *digits)
{
	struct osmo_cc_ie_keypad *ie_keypad;

	ie_keypad = osmo_cc_add_ie(msg, OSMO_CC_IE_KEYPAD, sizeof(*ie_keypad) + strlen(digits));
	memcpy(ie_keypad->digits, digits, strlen(digits));
}

/* helper to decode keypad press */
int osmo_cc_get_ie_keypad(osmo_cc_msg_t *msg, int ie_repeat, char *digits, size_t digits_size)
{
	struct osmo_cc_ie_keypad *ie_keypad;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_KEYPAD, ie_repeat, sizeof(*ie_keypad), (const void **)&ie_keypad);
	if (rc < 0)
		return rc;
	_ie2string(digits, digits_size, ie_keypad->digits, rc);
	return rc;
}

/* helper to encode call progress information */
void osmo_cc_add_ie_progress(osmo_cc_msg_t *msg, uint8_t coding, uint8_t location, uint8_t progress)
{
	struct osmo_cc_ie_progress *ie_progress;

	ie_progress = osmo_cc_add_ie(msg, OSMO_CC_IE_PROGRESS, sizeof(*ie_progress));
	ie_progress->coding = coding;
	ie_progress->location = location;
	ie_progress->progress = progress;
}

/* helper to decode call progress information */
int osmo_cc_get_ie_progress(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *coding, uint8_t *location, uint8_t *progress)
{
	struct osmo_cc_ie_progress *ie_progress;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_PROGRESS, ie_repeat, sizeof(*ie_progress), (const void **)&ie_progress);
	if (rc < 0)
		return rc;
	*coding = ie_progress->coding;
	*location = ie_progress->location;
	*progress = ie_progress->progress;
	return rc;
}

/* helper to encode notification */
void osmo_cc_add_ie_notify(osmo_cc_msg_t *msg, uint8_t notify)
{
	struct osmo_cc_ie_notify *ie_notify;

	ie_notify = osmo_cc_add_ie(msg, OSMO_CC_IE_NOTIFY, sizeof(*ie_notify));
	ie_notify->notify = notify;
}

/* helper to decode notification */
int osmo_cc_get_ie_notify(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *notify)
{
	struct osmo_cc_ie_notify *ie_notify;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_NOTIFY, ie_repeat, sizeof(*ie_notify), (const void **)&ie_notify);
	if (rc < 0)
		return rc;
	*notify = ie_notify->notify;
	return rc;
}

/* helper to encode cause */
void osmo_cc_add_ie_cause(osmo_cc_msg_t *msg, uint8_t location, uint8_t isdn_cause, uint16_t sip_cause, uint8_t socket_cause)
{
	struct osmo_cc_ie_cause *ie_cause;

	ie_cause = osmo_cc_add_ie(msg, OSMO_CC_IE_CAUSE, sizeof(*ie_cause));
	ie_cause->location = location;
	ie_cause->isdn_cause = isdn_cause;
	ie_cause->sip_cause_networkorder = htons(sip_cause);
	ie_cause->socket_cause = socket_cause;
}

/* helper to deccode cause */
int osmo_cc_get_ie_cause(osmo_cc_msg_t *msg, int ie_repeat, uint8_t *location, uint8_t *isdn_cause, uint16_t *sip_cause, uint8_t *socket_cause)
{
	struct osmo_cc_ie_cause *ie_cause;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_CAUSE, ie_repeat, sizeof(*ie_cause), (const void **)&ie_cause);
	if (rc < 0)
		return rc;
	*location = ie_cause->location;
	*isdn_cause = ie_cause->isdn_cause;
	*sip_cause = ntohs(ie_cause->sip_cause_networkorder);
	*socket_cause = ie_cause->socket_cause;
	return rc;
}

/* helper to encode DISPLAY information */
void osmo_cc_add_ie_display(osmo_cc_msg_t *msg, const char *text)
{
	struct osmo_cc_ie_display *ie_display;

	ie_display = osmo_cc_add_ie(msg, OSMO_CC_IE_DISPLAY, sizeof(*ie_display) + strlen(text));
	memcpy(ie_display->text, text, strlen(text));
}

/* helper to decode DISPLAY information */
int osmo_cc_get_ie_display(osmo_cc_msg_t *msg, int ie_repeat, char *text, size_t text_size)
{
	struct osmo_cc_ie_display *ie_display;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_DISPLAY, ie_repeat, sizeof(*ie_display), (const void **)&ie_display);
	if (rc < 0)
		return rc;
	_ie2string(text, text_size, ie_display->text, rc);
	return rc;
}

/* helper to encode SDP */
void osmo_cc_add_ie_sdp(osmo_cc_msg_t *msg, const char *sdp)
{
	struct osmo_cc_ie_sdp *ie_sdp;

	ie_sdp = osmo_cc_add_ie(msg, OSMO_CC_IE_SDP, sizeof(*ie_sdp) + strlen(sdp));
	memcpy(ie_sdp->sdp, sdp, strlen(sdp));
}

/* helper to decode SDP */
int osmo_cc_get_ie_sdp(osmo_cc_msg_t *msg, int ie_repeat, char *sdp, size_t sdp_size)
{
	struct osmo_cc_ie_sdp *ie_sdp;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_SDP, ie_repeat, sizeof(*ie_sdp), (const void **)&ie_sdp);
	if (rc < 0)
		return rc;
	_ie2string(sdp, sdp_size, ie_sdp->sdp, rc);
	return rc;
}

/* helper to encode socket addresss */
void osmo_cc_add_ie_socket_address(osmo_cc_msg_t *msg, const char *address)
{
	struct osmo_cc_ie_socket_address *ie_socket_address;

	ie_socket_address = osmo_cc_add_ie(msg, OSMO_CC_IE_SOCKET_ADDRESS, sizeof(*ie_socket_address) + strlen(address));
	memcpy(ie_socket_address->address, address, strlen(address));
}

/* helper to decode socket addresss */
int osmo_cc_get_ie_socket_address(osmo_cc_msg_t *msg, int ie_repeat, char *address, size_t address_size)
{
	struct osmo_cc_ie_socket_address *ie_socket_address;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_SOCKET_ADDRESS, ie_repeat, sizeof(*ie_socket_address), (const void **)&ie_socket_address);
	if (rc < 0)
		return rc;
	_ie2string(address, address_size, ie_socket_address->address, rc);
	return rc;
}

/* helper to encode private information element */
void osmo_cc_add_ie_private(osmo_cc_msg_t *msg, uint32_t unique, const uint8_t *data, size_t data_size)
{
	struct osmo_cc_ie_private *ie_private;

	ie_private = osmo_cc_add_ie(msg, OSMO_CC_IE_PRIVATE, sizeof(*ie_private) + data_size);
	ie_private->unique_networkorder = htonl(unique);
	memcpy(ie_private->data, data, data_size);
}

/* helper to decode private information element */
int osmo_cc_get_ie_private(osmo_cc_msg_t *msg, int ie_repeat, uint32_t *unique, uint8_t *data, size_t data_size)
{
	struct osmo_cc_ie_private *ie_private;
	int rc;

	rc = osmo_cc_get_ie_data(msg, OSMO_CC_IE_PRIVATE, ie_repeat, sizeof(*ie_private), (const void **)&ie_private);
	if (rc < 0)
		return rc;
	*unique = ntohl(ie_private->unique_networkorder);
	memcpy(data, ie_private->data, (rc < (int)data_size) ? rc : (int)data_size);
	return rc;
}