sig_pri.c

			default:
				ast_verb(2, "core_id:%d %s CC request unknown status %d\n",
					monitor->core_id, sig_pri_cc_type_name,
					subcmd->u.cc_request_rsp.status);
				ast_cc_monitor_failed(monitor->core_id, monitor->name,
					"%s CC request unknown status", sig_pri_cc_type_name);
				break;
			}
			ao2_ref(monitor, -1);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_REMOTE_USER_FREE:
			monitor = sig_pri_find_cc_monitor_by_cc_id(pri,
				subcmd->u.cc_remote_user_free.cc_id);
			if (!monitor) {
				pri_cc_cancel(pri->pri, subcmd->u.cc_remote_user_free.cc_id);
				break;
			}
			ast_cc_monitor_callee_available(monitor->core_id,
				"%s callee has become available", sig_pri_cc_type_name);
			ao2_ref(monitor, -1);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_B_FREE:
			monitor = sig_pri_find_cc_monitor_by_cc_id(pri,
				subcmd->u.cc_b_free.cc_id);
			if (!monitor) {
				pri_cc_cancel(pri->pri, subcmd->u.cc_b_free.cc_id);
				break;
			}
			ast_cc_monitor_party_b_free(monitor->core_id);
			ao2_ref(monitor, -1);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_STATUS_REQ:
			monitor = sig_pri_find_cc_monitor_by_cc_id(pri,
				subcmd->u.cc_status_req.cc_id);
			if (!monitor) {
				pri_cc_cancel(pri->pri, subcmd->u.cc_status_req.cc_id);
				break;
			}
			ast_cc_monitor_status_request(monitor->core_id);
			ao2_ref(monitor, -1);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_STATUS_REQ_RSP:
			agent = sig_pri_find_cc_agent_by_cc_id(pri, subcmd->u.cc_status_req_rsp.cc_id);
			if (!agent) {
				pri_cc_cancel(pri->pri, subcmd->u.cc_status_req_rsp.cc_id);
				break;
			}
			ast_cc_agent_status_response(agent->core_id,
				subcmd->u.cc_status_req_rsp.status ? AST_DEVICE_INUSE
				: AST_DEVICE_NOT_INUSE);
			ao2_ref(agent, -1);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_STATUS:
			agent = sig_pri_find_cc_agent_by_cc_id(pri, subcmd->u.cc_status.cc_id);
			if (!agent) {
				pri_cc_cancel(pri->pri, subcmd->u.cc_status.cc_id);
				break;
			}
			if (subcmd->u.cc_status.status) {
				ast_cc_agent_caller_busy(agent->core_id, "%s agent caller is busy",
					sig_pri_cc_type_name);
			} else {
				ast_cc_agent_caller_available(agent->core_id,
					"%s agent caller is available", sig_pri_cc_type_name);
			}
			ao2_ref(agent, -1);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_CANCEL:
			sig_pri_cc_link_canceled(pri, subcmd->u.cc_cancel.cc_id,
				subcmd->u.cc_cancel.is_agent);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_STOP_ALERTING:
			monitor = sig_pri_find_cc_monitor_by_cc_id(pri,
				subcmd->u.cc_stop_alerting.cc_id);
			if (!monitor) {
				pri_cc_cancel(pri->pri, subcmd->u.cc_stop_alerting.cc_id);
				break;
			}
			ast_cc_monitor_stop_ringing(monitor->core_id);
			ao2_ref(monitor, -1);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_AOC_EVENTS)
		case PRI_SUBCMD_AOC_E:
			/* Queue AST_CONTROL_AOC frame */
			sig_pri_aoc_e_from_pri(&subcmd->u.aoc_e, NULL, 0);
			break;
#endif	/* defined(HAVE_PRI_AOC_EVENTS) */
		default:
			ast_debug(2, "Span %d: Unknown CIS subcommand(%d) in %s event.\n", pri->span,
				subcmd->cmd, pri_event2str(event_id));
			break;
		}
	}
}

#if defined(HAVE_PRI_AOC_EVENTS)
/*!
 * \internal
 * \brief detect if AOC-S subcmd is present.
 * \since 1.8
 *
 * \param subcmds Subcommands to process if any. (Could be NULL).
 *
 * \note Knowing whether or not an AOC-E subcmd is present on certain
 * PRI hangup events is necessary to determine what method to use to hangup
 * the ast_channel.  If an AOC-E subcmd just came in, then a new AOC-E was queued
 * on the ast_channel.  If a soft hangup is used, the AOC-E msg will never make it
 * across the bridge, but if a AST_CONTROL_HANGUP frame is queued behind it
 * we can ensure the AOC-E frame makes it to it's destination before the hangup
 * frame is read.
 *
 *
 * \retval 0 AOC-E is not present in subcmd list
 * \retval 1 AOC-E is present in subcmd list
 */
static int detect_aoc_e_subcmd(const struct pri_subcommands *subcmds)
{
	int i;

	if (!subcmds) {
		return 0;
	}
	for (i = 0; i < subcmds->counter_subcmd; ++i) {
		const struct pri_subcommand *subcmd = &subcmds->subcmd[i];
		if (subcmd->cmd == PRI_SUBCMD_AOC_E) {
			return 1;
		}
	}
	return 0;
}
#endif	/* defined(HAVE_PRI_AOC_EVENTS) */

/*!
 * \internal
 * \brief Handle the call associated PRI subcommand events.
 * \since 1.8
 *
 * \param pri PRI span control structure.
 * \param chanpos Channel position in the span.
 * \param event_id PRI event id
 * \param subcmds Subcommands to process if any. (Could be NULL).
 * \param call_rsp libpri opaque call structure to send any responses toward.
 * Could be NULL either because it is not available or the call is for the
 * dummy call reference.  However, this should not be NULL in the cases that
 * need to use the pointer to send a response message back.
 *
 * \note Assumes the pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pri->pvts[chanpos]) is already obtained.
 *
 * \return Nothing
 */
static void sig_pri_handle_subcmds(struct sig_pri_span *pri, int chanpos, int event_id,
	const struct pri_subcommands *subcmds, q931_call *call_rsp)
{
	int index;
	struct ast_channel *owner;
	struct ast_party_redirecting ast_redirecting;
#if defined(HAVE_PRI_TRANSFER)
	struct xfer_rsp_data xfer_rsp;
#endif	/* defined(HAVE_PRI_TRANSFER) */

	if (!subcmds) {
		return;
	}
	for (index = 0; index < subcmds->counter_subcmd; ++index) {
		const struct pri_subcommand *subcmd = &subcmds->subcmd[index];

		switch (subcmd->cmd) {
		case PRI_SUBCMD_CONNECTED_LINE:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				struct ast_party_connected_line ast_connected;
				int caller_id_update;

				/* Extract the connected line information */
				ast_party_connected_line_init(&ast_connected);
				sig_pri_party_id_convert(&ast_connected.id, &subcmd->u.connected_line.id,
					pri);
				ast_connected.id.tag = ast_strdup(pri->pvts[chanpos]->user_tag);

				caller_id_update = 0;
				if (ast_connected.id.name.str) {
					/* Save name for Caller-ID update */
					ast_copy_string(pri->pvts[chanpos]->cid_name,
						ast_connected.id.name.str, sizeof(pri->pvts[chanpos]->cid_name));
					caller_id_update = 1;
				}
				if (ast_connected.id.number.str) {
					/* Save number for Caller-ID update */
					ast_copy_string(pri->pvts[chanpos]->cid_num,
						ast_connected.id.number.str, sizeof(pri->pvts[chanpos]->cid_num));
					pri->pvts[chanpos]->cid_ton = ast_connected.id.number.plan;
					caller_id_update = 1;
				}
				ast_connected.source = AST_CONNECTED_LINE_UPDATE_SOURCE_ANSWER;

				pri->pvts[chanpos]->cid_subaddr[0] = '\0';
#if defined(HAVE_PRI_SUBADDR)
				if (ast_connected.id.subaddress.valid) {
					ast_party_subaddress_set(&ast_channel_caller(owner)->id.subaddress,
						&ast_connected.id.subaddress);
					if (ast_connected.id.subaddress.str) {
						ast_copy_string(pri->pvts[chanpos]->cid_subaddr,
							ast_connected.id.subaddress.str,
							sizeof(pri->pvts[chanpos]->cid_subaddr));
					}
				}
#endif	/* defined(HAVE_PRI_SUBADDR) */
				if (caller_id_update) {
					struct ast_party_caller ast_caller;

					pri->pvts[chanpos]->callingpres =
						ast_party_id_presentation(&ast_connected.id);
					sig_pri_set_caller_id(pri->pvts[chanpos]);

					ast_party_caller_set_init(&ast_caller, ast_channel_caller(owner));
					ast_caller.id = ast_connected.id;
					ast_caller.ani = ast_connected.id;
					ast_channel_set_caller_event(owner, &ast_caller, NULL);
				}

				/* Update the connected line information on the other channel */
				if (event_id != PRI_EVENT_RING) {
					/* This connected_line update was not from a SETUP message. */
					ast_channel_queue_connected_line_update(owner, &ast_connected, NULL);
				}

				ast_party_connected_line_free(&ast_connected);
				ast_channel_unlock(owner);
			}
			break;
		case PRI_SUBCMD_REDIRECTING:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				sig_pri_redirecting_convert(&ast_redirecting, &subcmd->u.redirecting,
					ast_channel_redirecting(owner), pri);
				ast_redirecting.orig.tag = ast_strdup(pri->pvts[chanpos]->user_tag);
				ast_redirecting.from.tag = ast_strdup(pri->pvts[chanpos]->user_tag);
				ast_redirecting.to.tag = ast_strdup(pri->pvts[chanpos]->user_tag);
				ast_channel_set_redirecting(owner, &ast_redirecting, NULL);
				if (event_id != PRI_EVENT_RING) {
					/* This redirection was not from a SETUP message. */

					/* Invalidate any earlier private redirecting id representations */
					ast_party_id_invalidate(&ast_redirecting.priv_orig);
					ast_party_id_invalidate(&ast_redirecting.priv_from);
					ast_party_id_invalidate(&ast_redirecting.priv_to);

					ast_channel_queue_redirecting_update(owner, &ast_redirecting, NULL);
				}
				ast_party_redirecting_free(&ast_redirecting);

				ast_channel_unlock(owner);
			}
			break;
#if defined(HAVE_PRI_CALL_REROUTING)
		case PRI_SUBCMD_REROUTING:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				struct pri_party_redirecting pri_deflection;

				if (!call_rsp) {
					ast_log(LOG_WARNING,
						"Span %d: %s tried CallRerouting/CallDeflection to '%s' without call!\n",
						pri->span, ast_channel_name(owner), subcmd->u.rerouting.deflection.to.number.str);
					ast_channel_unlock(owner);
					break;
				}
				if (ast_strlen_zero(subcmd->u.rerouting.deflection.to.number.str)) {
					ast_log(LOG_WARNING,
						"Span %d: %s tried CallRerouting/CallDeflection to empty number!\n",
						pri->span, ast_channel_name(owner));
					pri_rerouting_rsp(pri->pri, call_rsp, subcmd->u.rerouting.invoke_id,
						PRI_REROUTING_RSP_INVALID_NUMBER);
					ast_channel_unlock(owner);
					break;
				}

				ast_verb(3, "Span %d: %s is CallRerouting/CallDeflection to '%s'.\n",
					pri->span, ast_channel_name(owner), subcmd->u.rerouting.deflection.to.number.str);

				/*
				 * Send back positive ACK to CallRerouting/CallDeflection.
				 *
				 * Note:  This call will be hungup by the core when it processes
				 * the call_forward string.
				 */
				pri_rerouting_rsp(pri->pri, call_rsp, subcmd->u.rerouting.invoke_id,
					PRI_REROUTING_RSP_OK_CLEAR);

				pri_deflection = subcmd->u.rerouting.deflection;

				/* Adjust the deflecting to number based upon the subscription option. */
				switch (subcmd->u.rerouting.subscription_option) {
				case 0:	/* noNotification */
				case 1:	/* notificationWithoutDivertedToNr */
					/* Delete the number because the far end is not supposed to see it. */
					pri_deflection.to.number.presentation =
						PRI_PRES_RESTRICTED | PRI_PRES_USER_NUMBER_UNSCREENED;
					pri_deflection.to.number.plan =
						(PRI_TON_UNKNOWN << 4) | PRI_NPI_E163_E164;
					pri_deflection.to.number.str[0] = '\0';
					break;
				case 2:	/* notificationWithDivertedToNr */
					break;
				case 3:	/* notApplicable */
				default:
					break;
				}
				sig_pri_redirecting_convert(&ast_redirecting, &pri_deflection,
					ast_channel_redirecting(owner), pri);
				ast_redirecting.orig.tag = ast_strdup(pri->pvts[chanpos]->user_tag);
				ast_redirecting.from.tag = ast_strdup(pri->pvts[chanpos]->user_tag);
				ast_redirecting.to.tag = ast_strdup(pri->pvts[chanpos]->user_tag);
				ast_channel_set_redirecting(owner, &ast_redirecting, NULL);
				ast_party_redirecting_free(&ast_redirecting);

				/* Request the core to forward to the new number. */
				ast_channel_call_forward_set(owner, subcmd->u.rerouting.deflection.to.number.str);

				/* Wake up the channel. */
				ast_queue_frame(owner, &ast_null_frame);

				ast_channel_unlock(owner);
			}
			break;
#endif	/* defined(HAVE_PRI_CALL_REROUTING) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_AVAILABLE:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				enum ast_cc_service_type service;

				switch (event_id) {
				case PRI_EVENT_RINGING:
					service = AST_CC_CCNR;
					break;
				case PRI_EVENT_HANGUP_REQ:
					/* We will assume that the cause was busy/congestion. */
					service = AST_CC_CCBS;
					break;
				default:
					service = AST_CC_NONE;
					break;
				}
				if (service == AST_CC_NONE
					|| sig_pri_cc_available(pri, chanpos, subcmd->u.cc_available.cc_id,
					service)) {
					pri_cc_cancel(pri->pri, subcmd->u.cc_available.cc_id);
				}
				ast_channel_unlock(owner);
			} else {
				/* No asterisk channel. */
				pri_cc_cancel(pri->pri, subcmd->u.cc_available.cc_id);
			}
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_CALL:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				struct ast_cc_agent *agent;

				agent = sig_pri_find_cc_agent_by_cc_id(pri, subcmd->u.cc_call.cc_id);
				if (agent) {
					ast_setup_cc_recall_datastore(owner, agent->core_id);
					ast_cc_agent_set_interfaces_chanvar(owner);
					ast_cc_agent_recalling(agent->core_id,
						"%s caller is attempting recall", sig_pri_cc_type_name);
					ao2_ref(agent, -1);
				}

				ast_channel_unlock(owner);
			}
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_CCSS)
		case PRI_SUBCMD_CC_CANCEL:
			sig_pri_cc_link_canceled(pri, subcmd->u.cc_cancel.cc_id,
				subcmd->u.cc_cancel.is_agent);
			break;
#endif	/* defined(HAVE_PRI_CCSS) */
#if defined(HAVE_PRI_TRANSFER)
		case PRI_SUBCMD_TRANSFER_CALL:
			if (!call_rsp) {
				/* Should never happen. */
				ast_log(LOG_ERROR,
					"Call transfer subcommand without call to send response!\n");
				break;
			}

			sig_pri_unlock_private(pri->pvts[chanpos]);
			xfer_rsp.pri = pri;
			xfer_rsp.call = call_rsp;
			xfer_rsp.invoke_id = subcmd->u.transfer.invoke_id;
			sig_pri_attempt_transfer(pri,
				subcmd->u.transfer.call_1, subcmd->u.transfer.is_call_1_held,
				subcmd->u.transfer.call_2, subcmd->u.transfer.is_call_2_held,
				sig_pri_transfer_rsp, &xfer_rsp);
			sig_pri_lock_private(pri->pvts[chanpos]);
			break;
#endif	/* defined(HAVE_PRI_TRANSFER) */
#if defined(HAVE_PRI_AOC_EVENTS)
		case PRI_SUBCMD_AOC_S:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				sig_pri_aoc_s_from_pri(&subcmd->u.aoc_s, owner,
					(pri->aoc_passthrough_flag & SIG_PRI_AOC_GRANT_S));
				ast_channel_unlock(owner);
			}
			break;
#endif	/* defined(HAVE_PRI_AOC_EVENTS) */
#if defined(HAVE_PRI_AOC_EVENTS)
		case PRI_SUBCMD_AOC_D:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				/* Queue AST_CONTROL_AOC frame on channel */
				sig_pri_aoc_d_from_pri(&subcmd->u.aoc_d, owner,
					(pri->aoc_passthrough_flag & SIG_PRI_AOC_GRANT_D));
				ast_channel_unlock(owner);
			}
			break;
#endif	/* defined(HAVE_PRI_AOC_EVENTS) */
#if defined(HAVE_PRI_AOC_EVENTS)
		case PRI_SUBCMD_AOC_E:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			/* Queue AST_CONTROL_AOC frame */
			sig_pri_aoc_e_from_pri(&subcmd->u.aoc_e, owner,
				(pri->aoc_passthrough_flag & SIG_PRI_AOC_GRANT_E));
			if (owner) {
				ast_channel_unlock(owner);
			}
			break;
#endif	/* defined(HAVE_PRI_AOC_EVENTS) */
#if defined(HAVE_PRI_AOC_EVENTS)
		case PRI_SUBCMD_AOC_CHARGING_REQ:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			if (owner) {
				sig_pri_aoc_request_from_pri(&subcmd->u.aoc_request, pri->pvts[chanpos],
					call_rsp);
				ast_channel_unlock(owner);
			}
			break;
#endif	/* defined(HAVE_PRI_AOC_EVENTS) */
#if defined(HAVE_PRI_AOC_EVENTS)
		case PRI_SUBCMD_AOC_CHARGING_REQ_RSP:
			/*
			 * An AOC request response may contain an AOC-S rate list.
			 * If this is the case handle this just like we
			 * would an incoming AOC-S msg.
			 */
			if (subcmd->u.aoc_request_response.valid_aoc_s) {
				sig_pri_lock_owner(pri, chanpos);
				owner = pri->pvts[chanpos]->owner;
				if (owner) {
					sig_pri_aoc_s_from_pri(&subcmd->u.aoc_request_response.aoc_s, owner,
						(pri->aoc_passthrough_flag & SIG_PRI_AOC_GRANT_S));
					ast_channel_unlock(owner);
				}
			}
			break;
#endif	/* defined(HAVE_PRI_AOC_EVENTS) */
#if defined(HAVE_PRI_MCID)
		case PRI_SUBCMD_MCID_REQ:
			sig_pri_lock_owner(pri, chanpos);
			owner = pri->pvts[chanpos]->owner;
			sig_pri_mcid_event(pri, &subcmd->u.mcid_req, owner);
			if (owner) {
				ast_channel_unlock(owner);
			}
			break;
#endif	/* defined(HAVE_PRI_MCID) */
#if defined(HAVE_PRI_MCID)
		case PRI_SUBCMD_MCID_RSP:
			/* Ignore for now. */
			break;
#endif	/* defined(HAVE_PRI_MCID) */
#if defined(HAVE_PRI_DISPLAY_TEXT)
		case PRI_SUBCMD_DISPLAY_TEXT:
			if (event_id != PRI_EVENT_RING) {
				/*
				 * This display text was not from a SETUP message.  We can do
				 * something with this display text string.
				 */
				sig_pri_lock_owner(pri, chanpos);
				owner = pri->pvts[chanpos]->owner;
				if (owner) {
					struct ast_frame f;

					/* Pass the display text to the peer channel. */
					memset(&f, 0, sizeof(f));
					f.frametype = AST_FRAME_TEXT;
					f.subclass.integer = 0;
					f.offset = 0;
					f.data.ptr = &subcmd->u.display.text;
					f.datalen = subcmd->u.display.length + 1;
					ast_queue_frame(owner, &f);
					ast_channel_unlock(owner);
				}
			}
			break;
#endif	/* defined(HAVE_PRI_DISPLAY_TEXT) */
		default:
			ast_debug(2, "Span %d: Unknown call subcommand(%d) in %s event.\n",
				pri->span, subcmd->cmd, pri_event2str(event_id));
			break;
		}
	}
}

/*!
 * \internal
 * \brief Convert the MOH state to string.
 * \since 10.0
 *
 * \param state MOH state to process.
 *
 * \return String version of MOH state.
 */
static const char *sig_pri_moh_state_str(enum sig_pri_moh_state state)
{
	const char *str;

	str = "Unknown";
	switch (state) {
	case SIG_PRI_MOH_STATE_IDLE:
		str = "SIG_PRI_MOH_STATE_IDLE";
		break;
	case SIG_PRI_MOH_STATE_NOTIFY:
		str = "SIG_PRI_MOH_STATE_NOTIFY";
		break;
	case SIG_PRI_MOH_STATE_MOH:
		str = "SIG_PRI_MOH_STATE_MOH";
		break;
#if defined(HAVE_PRI_CALL_HOLD)
	case SIG_PRI_MOH_STATE_HOLD_REQ:
		str = "SIG_PRI_MOH_STATE_HOLD_REQ";
		break;
	case SIG_PRI_MOH_STATE_PEND_UNHOLD:
		str = "SIG_PRI_MOH_STATE_PEND_UNHOLD";
		break;
	case SIG_PRI_MOH_STATE_HOLD:
		str = "SIG_PRI_MOH_STATE_HOLD";
		break;
	case SIG_PRI_MOH_STATE_RETRIEVE_REQ:
		str = "SIG_PRI_MOH_STATE_RETRIEVE_REQ";
		break;
	case SIG_PRI_MOH_STATE_PEND_HOLD:
		str = "SIG_PRI_MOH_STATE_PEND_HOLD";
		break;
	case SIG_PRI_MOH_STATE_RETRIEVE_FAIL:
		str = "SIG_PRI_MOH_STATE_RETRIEVE_FAIL";
		break;
#endif	/* defined(HAVE_PRI_CALL_HOLD) */
	case SIG_PRI_MOH_STATE_NUM:
		/* Not a real state. */
		break;
	}
	return str;
}

/*!
 * \internal
 * \brief Convert the MOH event to string.
 * \since 10.0
 *
 * \param event MOH event to process.
 *
 * \return String version of MOH event.
 */
static const char *sig_pri_moh_event_str(enum sig_pri_moh_event event)
{
	const char *str;

	str = "Unknown";
	switch (event) {
	case SIG_PRI_MOH_EVENT_RESET:
		str = "SIG_PRI_MOH_EVENT_RESET";
		break;
	case SIG_PRI_MOH_EVENT_HOLD:
		str = "SIG_PRI_MOH_EVENT_HOLD";
		break;
	case SIG_PRI_MOH_EVENT_UNHOLD:
		str = "SIG_PRI_MOH_EVENT_UNHOLD";
		break;
#if defined(HAVE_PRI_CALL_HOLD)
	case SIG_PRI_MOH_EVENT_HOLD_ACK:
		str = "SIG_PRI_MOH_EVENT_HOLD_ACK";
		break;
	case SIG_PRI_MOH_EVENT_HOLD_REJ:
		str = "SIG_PRI_MOH_EVENT_HOLD_REJ";
		break;
	case SIG_PRI_MOH_EVENT_RETRIEVE_ACK:
		str = "SIG_PRI_MOH_EVENT_RETRIEVE_ACK";
		break;
	case SIG_PRI_MOH_EVENT_RETRIEVE_REJ:
		str = "SIG_PRI_MOH_EVENT_RETRIEVE_REJ";
		break;
	case SIG_PRI_MOH_EVENT_REMOTE_RETRIEVE_ACK:
		str = "SIG_PRI_MOH_EVENT_REMOTE_RETRIEVE_ACK";
		break;
#endif	/* defined(HAVE_PRI_CALL_HOLD) */
	case SIG_PRI_MOH_EVENT_NUM:
		/* Not a real event. */
		break;
	}
	return str;
}

#if defined(HAVE_PRI_CALL_HOLD)
/*!
 * \internal
 * \brief Retrieve a call that was placed on hold by the HOLD message.
 * \since 10.0
 *
 * \param pvt Channel private control structure.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_retrieve_call(struct sig_pri_chan *pvt)
{
	int chanpos;
	int channel;

	if (pvt->pri->nodetype == PRI_NETWORK) {
		/* Find an available channel to propose */
		chanpos = pri_find_empty_chan(pvt->pri, 1);
		if (chanpos < 0) {
			/* No channels available. */
			return SIG_PRI_MOH_STATE_RETRIEVE_FAIL;
		}
		channel = PVT_TO_CHANNEL(pvt->pri->pvts[chanpos]);

		/*
		 * We cannot occupy or reserve this channel at this time because
		 * the retrieve may fail or we could have a RETRIEVE collision.
		 */
	} else {
		/* Let the network pick the channel. */
		channel = 0;
	}

	if (pri_retrieve(pvt->pri->pri, pvt->call, channel)) {
		return SIG_PRI_MOH_STATE_RETRIEVE_FAIL;
	}
	return SIG_PRI_MOH_STATE_RETRIEVE_REQ;
}
#endif	/* defined(HAVE_PRI_CALL_HOLD) */

/*!
 * \internal
 * \brief MOH FSM state idle.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_fsm_idle(struct ast_channel *chan, struct sig_pri_chan *pvt, enum sig_pri_moh_event event)
{
	enum sig_pri_moh_state next_state;

	next_state = pvt->moh_state;
	switch (event) {
	case SIG_PRI_MOH_EVENT_HOLD:
		if (!strcasecmp(pvt->mohinterpret, "passthrough")) {
			/*
			 * This config setting is deprecated.
			 * The old way did not send MOH just in case the notification was ignored.
			 */
			pri_notify(pvt->pri->pri, pvt->call, pvt->prioffset, PRI_NOTIFY_REMOTE_HOLD);
			next_state = SIG_PRI_MOH_STATE_NOTIFY;
			break;
		}

		switch (pvt->pri->moh_signaling) {
		default:
		case SIG_PRI_MOH_SIGNALING_MOH:
			ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
			next_state = SIG_PRI_MOH_STATE_MOH;
			break;
		case SIG_PRI_MOH_SIGNALING_NOTIFY:
			/* Send MOH anyway in case the far end does not interpret the notification. */
			ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);

			pri_notify(pvt->pri->pri, pvt->call, pvt->prioffset, PRI_NOTIFY_REMOTE_HOLD);
			next_state = SIG_PRI_MOH_STATE_NOTIFY;
			break;
#if defined(HAVE_PRI_CALL_HOLD)
		case SIG_PRI_MOH_SIGNALING_HOLD:
			if (pri_hold(pvt->pri->pri, pvt->call)) {
				/* Fall back to MOH instead */
				ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
				next_state = SIG_PRI_MOH_STATE_MOH;
			} else {
				next_state = SIG_PRI_MOH_STATE_HOLD_REQ;
			}
			break;
#endif	/* defined(HAVE_PRI_CALL_HOLD) */
		}
		break;
	default:
		break;
	}
	pvt->moh_state = next_state;
	return next_state;
}

/*!
 * \internal
 * \brief MOH FSM state notify remote party.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_fsm_notify(struct ast_channel *chan, struct sig_pri_chan *pvt, enum sig_pri_moh_event event)
{
	enum sig_pri_moh_state next_state;

	next_state = pvt->moh_state;
	switch (event) {
	case SIG_PRI_MOH_EVENT_HOLD:
		if (strcasecmp(pvt->mohinterpret, "passthrough")) {
			/* Restart MOH in case it was stopped by other means. */
			ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
		}
		break;
	case SIG_PRI_MOH_EVENT_UNHOLD:
		pri_notify(pvt->pri->pri, pvt->call, pvt->prioffset, PRI_NOTIFY_REMOTE_RETRIEVAL);
		/* Fall through */
	case SIG_PRI_MOH_EVENT_RESET:
		ast_moh_stop(chan);
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	default:
		break;
	}
	pvt->moh_state = next_state;
	return next_state;
}

/*!
 * \internal
 * \brief MOH FSM state generate moh.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_fsm_moh(struct ast_channel *chan, struct sig_pri_chan *pvt, enum sig_pri_moh_event event)
{
	enum sig_pri_moh_state next_state;

	next_state = pvt->moh_state;
	switch (event) {
	case SIG_PRI_MOH_EVENT_HOLD:
		/* Restart MOH in case it was stopped by other means. */
		ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
		break;
	case SIG_PRI_MOH_EVENT_RESET:
	case SIG_PRI_MOH_EVENT_UNHOLD:
		ast_moh_stop(chan);
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	default:
		break;
	}
	pvt->moh_state = next_state;
	return next_state;
}

#if defined(HAVE_PRI_CALL_HOLD)
/*!
 * \internal
 * \brief MOH FSM state hold requested.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_fsm_hold_req(struct ast_channel *chan, struct sig_pri_chan *pvt, enum sig_pri_moh_event event)
{
	enum sig_pri_moh_state next_state;

	next_state = pvt->moh_state;
	switch (event) {
	case SIG_PRI_MOH_EVENT_RESET:
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	case SIG_PRI_MOH_EVENT_UNHOLD:
		next_state = SIG_PRI_MOH_STATE_PEND_UNHOLD;
		break;
	case SIG_PRI_MOH_EVENT_HOLD_REJ:
		/* Fall back to MOH */
		if (chan) {
			ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
		}
		next_state = SIG_PRI_MOH_STATE_MOH;
		break;
	case SIG_PRI_MOH_EVENT_HOLD_ACK:
		next_state = SIG_PRI_MOH_STATE_HOLD;
		break;
	default:
		break;
	}
	pvt->moh_state = next_state;
	return next_state;
}
#endif	/* defined(HAVE_PRI_CALL_HOLD) */

#if defined(HAVE_PRI_CALL_HOLD)
/*!
 * \internal
 * \brief MOH FSM state hold requested with pending unhold.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_fsm_pend_unhold(struct ast_channel *chan, struct sig_pri_chan *pvt, enum sig_pri_moh_event event)
{
	enum sig_pri_moh_state next_state;

	next_state = pvt->moh_state;
	switch (event) {
	case SIG_PRI_MOH_EVENT_RESET:
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	case SIG_PRI_MOH_EVENT_HOLD:
		next_state = SIG_PRI_MOH_STATE_HOLD_REQ;
		break;
	case SIG_PRI_MOH_EVENT_HOLD_REJ:
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	case SIG_PRI_MOH_EVENT_HOLD_ACK:
		next_state = sig_pri_moh_retrieve_call(pvt);
		break;
	default:
		break;
	}
	pvt->moh_state = next_state;
	return next_state;
}
#endif	/* defined(HAVE_PRI_CALL_HOLD) */

#if defined(HAVE_PRI_CALL_HOLD)
/*!
 * \internal
 * \brief MOH FSM state hold.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_fsm_hold(struct ast_channel *chan, struct sig_pri_chan *pvt, enum sig_pri_moh_event event)
{
	enum sig_pri_moh_state next_state;

	next_state = pvt->moh_state;
	switch (event) {
	case SIG_PRI_MOH_EVENT_RESET:
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	case SIG_PRI_MOH_EVENT_UNHOLD:
		next_state = sig_pri_moh_retrieve_call(pvt);
		break;
	case SIG_PRI_MOH_EVENT_REMOTE_RETRIEVE_ACK:
		/* Fall back to MOH */
		if (chan) {
			ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
		}
		next_state = SIG_PRI_MOH_STATE_MOH;
		break;
	default:
		break;
	}
	pvt->moh_state = next_state;
	return next_state;
}
#endif	/* defined(HAVE_PRI_CALL_HOLD) */

#if defined(HAVE_PRI_CALL_HOLD)
/*!
 * \internal
 * \brief MOH FSM state retrieve requested.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state
 */
static enum sig_pri_moh_state sig_pri_moh_fsm_retrieve_req(struct ast_channel *chan, struct sig_pri_chan *pvt, enum sig_pri_moh_event event)
{
	enum sig_pri_moh_state next_state;

	next_state = pvt->moh_state;
	switch (event) {
	case SIG_PRI_MOH_EVENT_RESET:
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	case SIG_PRI_MOH_EVENT_HOLD:
		next_state = SIG_PRI_MOH_STATE_PEND_HOLD;
		break;
	case SIG_PRI_MOH_EVENT_RETRIEVE_ACK:
	case SIG_PRI_MOH_EVENT_REMOTE_RETRIEVE_ACK:
		next_state = SIG_PRI_MOH_STATE_IDLE;
		break;
	case SIG_PRI_MOH_EVENT_RETRIEVE_REJ:
		next_state = SIG_PRI_MOH_STATE_RETRIEVE_FAIL;
		break;
	default:
		break;
	}
	pvt->moh_state = next_state;
	return next_state;
}
#endif	/* defined(HAVE_PRI_CALL_HOLD) */

#if defined(HAVE_PRI_CALL_HOLD)
/*!
 * \internal
 * \brief MOH FSM state retrieve requested with pending hold.
 * \since 10.0
 *
 * \param chan Channel to post event to (Usually pvt->owner)
 * \param pvt Channel private control structure.
 * \param event MOH event to process.
 * 
 * \note Assumes the pvt->pri->lock is already obtained.
 * \note Assumes the sig_pri_lock_private(pvt) is already obtained.
 *
 * \return Next MOH state