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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2013, Digium, Inc.
*
* Joshua Colp <jcolp@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.
*/
/*** MODULEINFO
<depend>pjproject</depend>
<depend>res_pjsip</depend>
<depend>res_pjsip_session</depend>
<support_level>core</support_level>
***/
#include "asterisk.h"
#include <pjsip.h>
#include <pjsip_ua.h>
#include "asterisk/res_pjsip.h"
#include "asterisk/res_pjsip_session.h"
#include "asterisk/module.h"
#include "asterisk/pbx.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/bridge.h"
#include "asterisk/framehook.h"
#include "asterisk/stasis_bridges.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/causes.h"
/*! \brief REFER Progress structure */
struct refer_progress {
/*! \brief Subscription to provide updates on */
pjsip_evsub *sub;
/*! \brief Dialog for subscription */
pjsip_dialog *dlg;
/*! \brief Received packet, used to construct final response in case no subscription exists */
pjsip_rx_data *rdata;
/*! \brief Frame hook for monitoring REFER progress */
int framehook;
/*! \brief Last received subclass in frame hook */
int subclass;
/*! \brief Serializer for notifications */
struct ast_taskprocessor *serializer;
/*! \brief Stasis subscription for bridge events */
struct stasis_subscription *bridge_sub;
/*! \brief Reference to transfer_channel_data related to the refer */
struct transfer_channel_data *transfer_data;
/*! \brief Uniqueid of transferee channel */
char *transferee;
/*! \brief Non-zero if the 100 notify has been sent */
int sent_100;
/*! \brief Whether to notifies all the progress details on blind transfer */
unsigned int refer_blind_progress;
};
/*! \brief REFER Progress notification structure */
struct refer_progress_notification {
/*! \brief Refer progress structure to send notification on */
struct refer_progress *progress;
/*! \brief SIP response code to send */
int response;
/*! \brief Subscription state */
pjsip_evsub_state state;
};
/*! \brief REFER Progress module, used to attach REFER progress structure to subscriptions */
static pjsip_module refer_progress_module = {
.name = { "REFER Progress", 14 },
.id = -1,
};
/*! \brief Destructor for REFER Progress notification structure */
static void refer_progress_notification_destroy(void *obj)
{
struct refer_progress_notification *notification = obj;
ao2_cleanup(notification->progress);
}
/*! \brief Allocator for REFER Progress notification structure */
static struct refer_progress_notification *refer_progress_notification_alloc(struct refer_progress *progress, int response,
pjsip_evsub_state state)
{
struct refer_progress_notification *notification = ao2_alloc(sizeof(*notification), refer_progress_notification_destroy);
if (!notification) {
return NULL;
}
ao2_ref(progress, +1);
notification->progress = progress;
notification->response = response;
notification->state = state;
return notification;
}
/*! \brief Serialized callback for subscription notification */
static int refer_progress_notify(void *data)
{
RAII_VAR(struct refer_progress_notification *, notification, data, ao2_cleanup);
pjsip_evsub *sub;
pjsip_tx_data *tdata;
/* If the subscription has already been terminated we can't send a notification */
if (!(sub = notification->progress->sub)) {
ast_debug(3, "Not sending NOTIFY of response '%d' and state '%u' on progress monitor '%p' as subscription has been terminated\n",
notification->response, notification->state, notification->progress);
return 0;
}
/* If the subscription is being terminated we want to actually remove the progress structure here to
* stop a deadlock from occurring - basically terminated changes the state which queues a synchronous task
* but we are already running a task... thus it would deadlock */
if (notification->state == PJSIP_EVSUB_STATE_TERMINATED) {
ast_debug(3, "Subscription '%p' is being terminated as a result of a NOTIFY, removing REFER progress structure early on progress monitor '%p'\n",
notification->progress->sub, notification->progress);
pjsip_dlg_inc_lock(notification->progress->dlg);
pjsip_evsub_set_mod_data(notification->progress->sub, refer_progress_module.id, NULL);
pjsip_dlg_dec_lock(notification->progress->dlg);
/* This is for dropping the reference on the subscription */
ao2_cleanup(notification->progress);
notification->progress->sub = NULL;
}
/* Send a deferred initial 100 Trying SIP frag NOTIFY if we haven't already. */
if (!notification->progress->sent_100) {
notification->progress->sent_100 = 1;
if (notification->response != 100) {
ast_debug(3, "Sending initial 100 Trying NOTIFY for progress monitor '%p'\n",
notification->progress);
if (pjsip_xfer_notify(sub, PJSIP_EVSUB_STATE_ACTIVE, 100, NULL, &tdata) == PJ_SUCCESS) {
pjsip_xfer_send_request(sub, tdata);
}
}
}
ast_debug(3, "Sending NOTIFY with response '%d' and state '%u' on subscription '%p' and progress monitor '%p'\n",
notification->response, notification->state, sub, notification->progress);
/* Actually send the notification */
if (pjsip_xfer_notify(sub, notification->state, notification->response, NULL, &tdata) == PJ_SUCCESS) {
pjsip_xfer_send_request(sub, tdata);
}
return 0;
}
static void refer_progress_bridge(void *data, struct stasis_subscription *sub,
struct stasis_message *message)
{
struct refer_progress *progress = data;
struct ast_bridge_blob *enter_blob;
struct refer_progress_notification *notification;
struct ast_channel *chan;
if (stasis_subscription_final_message(sub, message)) {
ao2_ref(progress, -1);
return;
}
if (ast_channel_entered_bridge_type() != stasis_message_type(message)) {
/* Don't care */
return;
}
enter_blob = stasis_message_data(message);
if (strcmp(enter_blob->channel->base->uniqueid, progress->transferee)) {
/* Don't care */
return;
}
if (!progress->transfer_data->completed) {
/* We can't act on this message because the transfer_channel_data doesn't show that
* the transfer is ready to progress */
return;
}
/* OMG the transferee is joining a bridge. His call got answered! */
notification = refer_progress_notification_alloc(progress, 200, PJSIP_EVSUB_STATE_TERMINATED);
if (notification) {
if (ast_sip_push_task(progress->serializer, refer_progress_notify, notification)) {
ao2_cleanup(notification);
}
progress->bridge_sub = stasis_unsubscribe(progress->bridge_sub);
}
chan = ast_channel_get_by_name(progress->transferee);
if (!chan) {
/* The channel is already gone */
return;
}
ast_channel_lock(chan);
ast_debug(3, "Detaching REFER progress monitoring hook from '%s' as it has joined a bridge\n",
ast_channel_name(chan));
ast_framehook_detach(chan, progress->framehook);
ast_channel_unlock(chan);
ast_channel_unref(chan);
}
/*! \brief Progress monitoring frame hook - examines frames to determine state of transfer */
static struct ast_frame *refer_progress_framehook(struct ast_channel *chan, struct ast_frame *f, enum ast_framehook_event event, void *data)
{
struct refer_progress *progress = data;
struct refer_progress_notification *notification = NULL;
/* We only care about frames *to* the channel */
if (!f || (event != AST_FRAMEHOOK_EVENT_WRITE)) {
return f;
}
/* If the completed flag hasn't been raised, skip this pass. */
if (!progress->transfer_data->completed) {
return f;
}
/* Determine the state of the REFER based on the control frames (or voice frames) passing */
if (f->frametype == AST_FRAME_VOICE && !progress->subclass) {
/* Media is passing without progress, this means the call has been answered */
notification = refer_progress_notification_alloc(progress, 200, PJSIP_EVSUB_STATE_TERMINATED);
} else if (f->frametype == AST_FRAME_CONTROL) {
/* Based on the control frame being written we can send a NOTIFY advising of the progress */
if ((f->subclass.integer == AST_CONTROL_RING) || (f->subclass.integer == AST_CONTROL_RINGING)) {
progress->subclass = f->subclass.integer;
notification = refer_progress_notification_alloc(progress, 180, PJSIP_EVSUB_STATE_ACTIVE);
} else if (f->subclass.integer == AST_CONTROL_BUSY) {
progress->subclass = f->subclass.integer;
notification = refer_progress_notification_alloc(progress, 486, PJSIP_EVSUB_STATE_TERMINATED);
} else if (f->subclass.integer == AST_CONTROL_CONGESTION) {
progress->subclass = f->subclass.integer;
notification = refer_progress_notification_alloc(progress, 503, PJSIP_EVSUB_STATE_TERMINATED);
} else if (f->subclass.integer == AST_CONTROL_PROGRESS) {
progress->subclass = f->subclass.integer;
notification = refer_progress_notification_alloc(progress, 183, PJSIP_EVSUB_STATE_ACTIVE);
} else if (f->subclass.integer == AST_CONTROL_PROCEEDING) {
progress->subclass = f->subclass.integer;
notification = refer_progress_notification_alloc(progress, 100, PJSIP_EVSUB_STATE_ACTIVE);
} else if (f->subclass.integer == AST_CONTROL_ANSWER) {
progress->subclass = f->subclass.integer;
notification = refer_progress_notification_alloc(progress, 200, PJSIP_EVSUB_STATE_TERMINATED);
}
}
/* If a notification is due to be sent push it to the thread pool */
if (notification) {
/* If the subscription is being terminated we don't need the frame hook any longer */
if (notification->state == PJSIP_EVSUB_STATE_TERMINATED) {
ast_debug(3, "Detaching REFER progress monitoring hook from '%s' as subscription is being terminated\n",
ast_channel_name(chan));
ast_framehook_detach(chan, progress->framehook);
}
if (ast_sip_push_task(progress->serializer, refer_progress_notify, notification)) {
ao2_cleanup(notification);
}
}
return f;
}
/*! \brief Destroy callback for monitoring framehook */
static void refer_progress_framehook_destroy(void *data)
{
struct refer_progress *progress = data;
struct refer_progress_notification *notification = refer_progress_notification_alloc(progress, 503, PJSIP_EVSUB_STATE_TERMINATED);
if (notification && ast_sip_push_task(progress->serializer, refer_progress_notify, notification)) {
ao2_cleanup(notification);
}
if (progress->bridge_sub) {
progress->bridge_sub = stasis_unsubscribe(progress->bridge_sub);
}
ao2_cleanup(progress);
}
/*! \brief Serialized callback for subscription termination */
static int refer_progress_terminate(void *data)
{
struct refer_progress *progress = data;
/* The subscription is no longer valid */
progress->sub = NULL;
return 0;
}
/*! \brief Callback for REFER subscription state changes */
static void refer_progress_on_evsub_state(pjsip_evsub *sub, pjsip_event *event)
{
struct refer_progress *progress = pjsip_evsub_get_mod_data(sub, refer_progress_module.id);
/* If being destroyed queue it up to the serializer */
if (progress && (pjsip_evsub_get_state(sub) == PJSIP_EVSUB_STATE_TERMINATED)) {
/* To prevent a deadlock race condition we unlock the dialog so other serialized tasks can execute */
ast_debug(3, "Subscription '%p' has been remotely terminated, waiting for other tasks to complete on progress monitor '%p'\n",
sub, progress);
/* It's possible that a task is waiting to remove us already, so bump the refcount of progress so it doesn't get destroyed */
ao2_ref(progress, +1);
pjsip_dlg_dec_lock(progress->dlg);
/*
* XXX We are always going to execute this inline rather than
* in the serializer because this function is a PJPROJECT
* callback and thus has to be a SIP servant thread.
*
* The likely remedy is to push most of this function into
* refer_progress_terminate() with ast_sip_push_task().
*/
ast_sip_push_task_wait_servant(progress->serializer, refer_progress_terminate, progress);
pjsip_dlg_inc_lock(progress->dlg);
ao2_ref(progress, -1);
ast_debug(3, "Subscription '%p' removed from progress monitor '%p'\n", sub, progress);
/* Since it was unlocked it is possible for this to have been removed already, so check again */
if (pjsip_evsub_get_mod_data(sub, refer_progress_module.id)) {
pjsip_evsub_set_mod_data(sub, refer_progress_module.id, NULL);
ao2_cleanup(progress);
}
}
}
/*! \brief Callback structure for subscription */
static pjsip_evsub_user refer_progress_evsub_cb = {
.on_evsub_state = refer_progress_on_evsub_state,
};
/*! \brief Destructor for REFER progress sutrcture */
static void refer_progress_destroy(void *obj)
{
struct refer_progress *progress = obj;
if (progress->bridge_sub) {
progress->bridge_sub = stasis_unsubscribe(progress->bridge_sub);
}
ao2_cleanup(progress->transfer_data);
ast_free(progress->transferee);
ast_taskprocessor_unreference(progress->serializer);
}
/*! \brief Internal helper function which sets up a refer progress structure if needed */
static int refer_progress_alloc(struct ast_sip_session *session, pjsip_rx_data *rdata, struct refer_progress **progress)
{
const pj_str_t str_refer_sub = { "Refer-Sub", 9 };
pjsip_generic_string_hdr *refer_sub = NULL;
const pj_str_t str_true = { "true", 4 };
pjsip_hdr hdr_list;
char tps_name[AST_TASKPROCESSOR_MAX_NAME + 1];
*progress = NULL;
/* Grab the optional Refer-Sub header, it can be used to suppress the implicit subscription */
refer_sub = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &str_refer_sub, NULL);
if ((refer_sub && pj_strnicmp(&refer_sub->hvalue, &str_true, 4))) {
return 0;
}
if (!(*progress = ao2_alloc(sizeof(struct refer_progress), refer_progress_destroy))) {
return -1;
}
ast_debug(3, "Created progress monitor '%p' for transfer occurring from channel '%s' and endpoint '%s'\n",
progress, ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
(*progress)->refer_blind_progress = session->endpoint->refer_blind_progress;
(*progress)->framehook = -1;
/* To prevent a potential deadlock we need the dialog so we can lock/unlock */
(*progress)->dlg = session->inv_session->dlg;
/* Create name with seq number appended. */
ast_taskprocessor_build_name(tps_name, sizeof(tps_name), "pjsip/refer/%s",
ast_sorcery_object_get_id(session->endpoint));
if (!((*progress)->serializer = ast_sip_create_serializer(tps_name))) {
goto error;
}
/* Create the implicit subscription for monitoring of this transfer */
if (pjsip_xfer_create_uas(session->inv_session->dlg, &refer_progress_evsub_cb, rdata, &(*progress)->sub) != PJ_SUCCESS) {
goto error;
}
/* Associate the REFER progress structure with the subscription */
ao2_ref(*progress, +1);
pjsip_evsub_set_mod_data((*progress)->sub, refer_progress_module.id, *progress);
pj_list_init(&hdr_list);
if (refer_sub) {
pjsip_hdr *hdr = (pjsip_hdr*)pjsip_generic_string_hdr_create(session->inv_session->dlg->pool, &str_refer_sub, &str_true);
pj_list_push_back(&hdr_list, hdr);
}
/* Accept the REFER request */
ast_debug(3, "Accepting REFER request for progress monitor '%p'\n", *progress);
pjsip_xfer_accept((*progress)->sub, rdata, 202, &hdr_list);
return 0;
error:
ao2_cleanup(*progress);
*progress = NULL;
return -1;
}
/*! \brief Structure for attended transfer task */
struct refer_attended {
/*! \brief Transferer session */
struct ast_sip_session *transferer;
/*! \brief Transferer channel */
struct ast_channel *transferer_chan;
/*! \brief Second transferer session */
struct ast_sip_session *transferer_second;
/*! \brief Optional refer progress structure */
struct refer_progress *progress;
};
/*! \brief Destructor for attended transfer task */
static void refer_attended_destroy(void *obj)
{
struct refer_attended *attended = obj;
ao2_cleanup(attended->transferer);
ast_channel_cleanup(attended->transferer_chan);
ao2_cleanup(attended->transferer_second);
ao2_cleanup(attended->progress);
}
/*! \brief Allocator for attended transfer task */
static struct refer_attended *refer_attended_alloc(struct ast_sip_session *transferer,
struct ast_sip_session *transferer_second,
struct refer_progress *progress)
{
struct refer_attended *attended;
attended = ao2_alloc_options(sizeof(*attended), refer_attended_destroy,
AO2_ALLOC_OPT_LOCK_NOLOCK);
if (!attended) {
return NULL;
}
ao2_ref(transferer, +1);
attended->transferer = transferer;
ast_channel_ref(transferer->channel);
attended->transferer_chan = transferer->channel;
ao2_ref(transferer_second, +1);
attended->transferer_second = transferer_second;
if (progress) {
ao2_ref(progress, +1);
attended->progress = progress;
}
return attended;
}
static int session_end_if_deferred_task(void *data)
{
struct ast_sip_session *session = data;
ast_sip_session_end_if_deferred(session);
ao2_ref(session, -1);
return 0;
}
static int defer_termination_cancel_task(void *data)
{
struct ast_sip_session *session = data;
ast_sip_session_end_if_deferred(session);
ast_sip_session_defer_termination_cancel(session);
ao2_ref(session, -1);
return 0;
}
/*!
* \internal
* \brief Convert transfer enum to SIP response code.
* \since 13.3.0
*
* \param xfer_code Core transfer function enum result.
*
* \return SIP response code
*/
static int xfer_response_code2sip(enum ast_transfer_result xfer_code)
{
int response;
response = 503;
switch (xfer_code) {
case AST_BRIDGE_TRANSFER_INVALID:
response = 400;
break;
case AST_BRIDGE_TRANSFER_NOT_PERMITTED:
response = 403;
break;
case AST_BRIDGE_TRANSFER_FAIL:
response = 500;
break;
case AST_BRIDGE_TRANSFER_SUCCESS:
response = 200;
break;
}
return response;
}
/*! \brief Task for attended transfer executed by attended->transferer_second serializer */
static int refer_attended_task(void *data)
{
struct refer_attended *attended = data;
int response;
int (*task_cb)(void *data);
if (attended->transferer_second->channel) {
ast_debug(3, "Performing a REFER attended transfer - Transferer #1: %s Transferer #2: %s\n",
ast_channel_name(attended->transferer_chan),
ast_channel_name(attended->transferer_second->channel));
response = xfer_response_code2sip(ast_bridge_transfer_attended(
attended->transferer_chan,
attended->transferer_second->channel));
ast_debug(3, "Final response for REFER attended transfer - Transferer #1: %s Transferer #2: %s is '%d'\n",
ast_channel_name(attended->transferer_chan),
ast_channel_name(attended->transferer_second->channel),
response);
} else {
ast_debug(3, "Received REFER request on channel '%s' but other channel has gone.\n",
ast_channel_name(attended->transferer_chan));
response = 603;
}
if (attended->progress) {
struct refer_progress_notification *notification;
notification = refer_progress_notification_alloc(attended->progress, response,
PJSIP_EVSUB_STATE_TERMINATED);
if (notification) {
refer_progress_notify(notification);
}
}
if (response == 200) {
task_cb = session_end_if_deferred_task;
} else {
task_cb = defer_termination_cancel_task;
}
if (!ast_sip_push_task(attended->transferer->serializer,
task_cb, attended->transferer)) {
/* Gave the ref to the pushed task. */
attended->transferer = NULL;
} else {
/* Do this anyway even though it is the wrong serializer. */
ast_sip_session_end_if_deferred(attended->transferer);
}
ao2_ref(attended, -1);
return 0;
}
/*! \brief Structure for blind transfer callback details */
struct refer_blind {
/*! \brief Context being used for transfer */
const char *context;
/*! \brief Optional progress structure */
struct refer_progress *progress;
/*! \brief REFER message */
pjsip_rx_data *rdata;
/*! \brief Optional Replaces header */
pjsip_replaces_hdr *replaces;
/*! \brief Optional Refer-To header */
pjsip_sip_uri *refer_to;
/*! \brief Attended transfer flag */
unsigned int attended:1;
};
/*! \brief Blind transfer callback function */
static void refer_blind_callback(struct ast_channel *chan, struct transfer_channel_data *user_data_wrapper,
enum ast_transfer_type transfer_type)
{
struct refer_blind *refer = user_data_wrapper->data;
pjsip_generic_string_hdr *referred_by;
static const pj_str_t str_referred_by = { "Referred-By", 11 };
static const pj_str_t str_referred_by_s = { "b", 1 };
pbx_builtin_setvar_helper(chan, "SIPTRANSFER", "yes");
if (refer->progress && !refer->attended && !refer->progress->refer_blind_progress) {
/* If blind transfer and endpoint doesn't want to receive all the progress details */
struct refer_progress_notification *notification = refer_progress_notification_alloc(refer->progress, 200,
PJSIP_EVSUB_STATE_TERMINATED);
if (notification) {
refer_progress_notify(notification);
}
} else if (refer->progress) {
/* If attended transfer and progress monitoring is being done attach a frame hook so we can monitor it */
struct ast_framehook_interface hook = {
.version = AST_FRAMEHOOK_INTERFACE_VERSION,
.event_cb = refer_progress_framehook,
.destroy_cb = refer_progress_framehook_destroy,
.data = refer->progress,
.disable_inheritance = 1,
};
refer->progress->transferee = ast_strdup(ast_channel_uniqueid(chan));
if (!refer->progress->transferee) {
struct refer_progress_notification *notification = refer_progress_notification_alloc(refer->progress, 200,
PJSIP_EVSUB_STATE_TERMINATED);
ast_log(LOG_WARNING, "Could not copy channel name '%s' during transfer - assuming success\n",
ast_channel_name(chan));
if (notification) {
refer_progress_notify(notification);
}
}
/* Progress needs a reference to the transfer_channel_data so that it can track the completed status of the transfer */
ao2_ref(user_data_wrapper, +1);
refer->progress->transfer_data = user_data_wrapper;
/* We need to bump the reference count up on the progress structure since it is in the frame hook now */
ao2_ref(refer->progress, +1);
/* If we can't attach a frame hook for whatever reason send a notification of success immediately */
ast_channel_lock(chan);
refer->progress->framehook = ast_framehook_attach(chan, &hook);
ast_channel_unlock(chan);
if (refer->progress->framehook < 0) {
struct refer_progress_notification *notification = refer_progress_notification_alloc(refer->progress, 200,
PJSIP_EVSUB_STATE_TERMINATED);
ast_log(LOG_WARNING, "Could not attach REFER transfer progress monitoring hook to channel '%s' - assuming success\n",
ast_channel_name(chan));
if (notification) {
refer_progress_notify(notification);
}
ao2_cleanup(refer->progress);
}
/* We need to bump the reference count for the stasis subscription */
ao2_ref(refer->progress, +1);
/* We also will need to detect if the transferee enters a bridge. This is currently the only reliable way to
* detect if the transfer target has answered the call
*/
refer->progress->bridge_sub = stasis_subscribe_pool(ast_bridge_topic_all(), refer_progress_bridge, refer->progress);
if (!refer->progress->bridge_sub) {
struct refer_progress_notification *notification = refer_progress_notification_alloc(refer->progress, 200,
PJSIP_EVSUB_STATE_TERMINATED);
ast_log(LOG_WARNING, "Could not create bridge stasis subscription for monitoring progress on transfer of channel '%s' - assuming success\n",
ast_channel_name(chan));
if (notification) {
refer_progress_notify(notification);
}
ast_channel_lock(chan);
ast_framehook_detach(chan, refer->progress->framehook);
ast_channel_unlock(chan);
ao2_cleanup(refer->progress);
} else {
stasis_subscription_accept_message_type(refer->progress->bridge_sub, ast_channel_entered_bridge_type());
stasis_subscription_accept_message_type(refer->progress->bridge_sub, stasis_subscription_change_type());
stasis_subscription_set_filter(refer->progress->bridge_sub, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);
}
}
pbx_builtin_setvar_helper(chan, "SIPREFERRINGCONTEXT", S_OR(refer->context, NULL));
referred_by = pjsip_msg_find_hdr_by_names(refer->rdata->msg_info.msg,
&str_referred_by, &str_referred_by_s, NULL);
if (referred_by) {
size_t uri_size = pj_strlen(&referred_by->hvalue) + 1;
char *uri = ast_alloca(uri_size);
ast_copy_pj_str(uri, &referred_by->hvalue, uri_size);
pbx_builtin_setvar_helper(chan, "__SIPREFERREDBYHDR", S_OR(uri, NULL));
} else {
pbx_builtin_setvar_helper(chan, "SIPREFERREDBYHDR", NULL);
}
if (refer->replaces) {
char replaces[512];
char *replaces_val = NULL;
int len;
len = pjsip_hdr_print_on(refer->replaces, replaces, sizeof(replaces) - 1);
if (len != -1) {
/* pjsip_hdr_print_on does not NULL terminate the buffer */
replaces[len] = '\0';
replaces_val = replaces + sizeof("Replaces:");
}
pbx_builtin_setvar_helper(chan, "__SIPREPLACESHDR", replaces_val);
} else {
pbx_builtin_setvar_helper(chan, "SIPREPLACESHDR", NULL);
}
if (refer->refer_to) {
char refer_to[PJSIP_MAX_URL_SIZE];
pjsip_uri_print(PJSIP_URI_IN_REQ_URI, refer->refer_to, refer_to, sizeof(refer_to));
pbx_builtin_setvar_helper(chan, "SIPREFERTOHDR", S_OR(refer_to, NULL));
} else {
pbx_builtin_setvar_helper(chan, "SIPREFERTOHDR", NULL);
}
}
/*!
* \internal
* \brief Set the passed in context variable to the determined transfer context.
* \since 13.3.0
*
* \param context Set to the determined transfer context.
* \param session INVITE dialog SIP session.
*/
#define DETERMINE_TRANSFER_CONTEXT(context, session) \
do { \
ast_channel_lock((session)->channel); \
context = pbx_builtin_getvar_helper((session)->channel, "TRANSFER_CONTEXT"); \
if (ast_strlen_zero(context)) { \
context = (session)->endpoint->context; \
} else { \
context = ast_strdupa(context); \
} \
ast_channel_unlock((session)->channel); \
} while (0) \
static int refer_incoming_attended_request(struct ast_sip_session *session, pjsip_rx_data *rdata, pjsip_sip_uri *target_uri,
pjsip_param *replaces_param, struct refer_progress *progress)
{
const pj_str_t str_replaces = { "Replaces", 8 };
pj_str_t replaces_content;
pjsip_replaces_hdr *replaces;
int parsed_len;
pjsip_dialog *dlg;
pj_strdup_with_null(rdata->tp_info.pool, &replaces_content, &replaces_param->value);
/* Parsing the parameter as a Replaces header easily grabs the needed information */
if (!(replaces = pjsip_parse_hdr(rdata->tp_info.pool, &str_replaces, replaces_content.ptr,
pj_strlen(&replaces_content), &parsed_len))) {
ast_log(LOG_ERROR, "Received REFER request on channel '%s' from endpoint '%s' with invalid Replaces header, rejecting\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
return 400;
}
/* See if the dialog is local, or remote */
if ((dlg = pjsip_ua_find_dialog(&replaces->call_id, &replaces->to_tag, &replaces->from_tag, PJ_TRUE))) {
RAII_VAR(struct ast_sip_session *, other_session, ast_sip_dialog_get_session(dlg), ao2_cleanup);
struct refer_attended *attended;
pjsip_dlg_dec_lock(dlg);
if (!other_session) {
ast_debug(3, "Received REFER request on channel '%s' from endpoint '%s' for local dialog but no session exists on it\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
return 603;
}
/* We defer actually doing the attended transfer to the other session so no deadlock can occur */
if (!(attended = refer_attended_alloc(session, other_session, progress))) {
ast_log(LOG_ERROR, "Received REFER request on channel '%s' from endpoint '%s' for local dialog but could not allocate structure to complete, rejecting\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
return 500;
}
if (ast_sip_session_defer_termination(session)) {
ast_log(LOG_ERROR, "Received REFER request on channel '%s' from endpoint '%s' for local dialog but could not defer termination, rejecting\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
ao2_cleanup(attended);
return 500;
}
/* Push it to the other session, which will have both channels with minimal locking */
if (ast_sip_push_task(other_session->serializer, refer_attended_task, attended)) {
ast_sip_session_end_if_deferred(session);
ast_sip_session_defer_termination_cancel(session);
ao2_cleanup(attended);
return 500;
}
ast_debug(3, "Attended transfer from '%s' pushed to second channel serializer\n",
ast_channel_name(session->channel));
return 200;
} else {
const char *context;
struct refer_blind refer = { 0, };
int response;
DETERMINE_TRANSFER_CONTEXT(context, session);
if (!ast_exists_extension(NULL, context, "external_replaces", 1, NULL)) {
ast_log(LOG_ERROR, "Received REFER for remote session on channel '%s' from endpoint '%s' but 'external_replaces' extension not found in context %s\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint), context);
return 404;
}
refer.context = context;
refer.progress = progress;
refer.rdata = rdata;
refer.replaces = replaces;
refer.refer_to = target_uri;
refer.attended = 1;
if (ast_sip_session_defer_termination(session)) {
ast_log(LOG_ERROR, "Received REFER for remote session on channel '%s' from endpoint '%s' but could not defer termination, rejecting\n",
ast_channel_name(session->channel),
ast_sorcery_object_get_id(session->endpoint));
return 500;
}
response = xfer_response_code2sip(ast_bridge_transfer_blind(1, session->channel,
"external_replaces", context, refer_blind_callback, &refer));
ast_sip_session_end_if_deferred(session);
if (response != 200) {
ast_sip_session_defer_termination_cancel(session);
}
return response;
}
}
static int refer_incoming_blind_request(struct ast_sip_session *session, pjsip_rx_data *rdata, pjsip_sip_uri *target,
struct refer_progress *progress)
{
const char *context;
char exten[AST_MAX_EXTENSION];
struct refer_blind refer = { 0, };
int response;
/* If no explicit transfer context has been provided use their configured context */
DETERMINE_TRANSFER_CONTEXT(context, session);
/* Using the user portion of the target URI see if it exists as a valid extension in their context */
ast_copy_pj_str(exten, &target->user, sizeof(exten));
/*
* We may want to match in the dialplan without any user
* options getting in the way.
*/
AST_SIP_USER_OPTIONS_TRUNCATE_CHECK(exten);
/* Uri without exten */
if (ast_strlen_zero(exten)) {
ast_copy_string(exten, "s", sizeof(exten));
ast_debug(3, "Channel '%s' from endpoint '%s' attempted blind transfer to a target without extension. Target was set to 's@%s'\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint), context);
}
if (!ast_exists_extension(NULL, context, exten, 1, NULL)) {
ast_log(LOG_ERROR, "Channel '%s' from endpoint '%s' attempted blind transfer to '%s@%s' but target does not exist\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint), exten, context);
return 404;
}
refer.context = context;
refer.progress = progress;
refer.rdata = rdata;
refer.refer_to = target;
refer.attended = 0;
if (ast_sip_session_defer_termination(session)) {
ast_log(LOG_ERROR, "Channel '%s' from endpoint '%s' attempted blind transfer but could not defer termination, rejecting\n",
ast_channel_name(session->channel),
ast_sorcery_object_get_id(session->endpoint));
return 500;
}
response = xfer_response_code2sip(ast_bridge_transfer_blind(1, session->channel,
exten, context, refer_blind_callback, &refer));
ast_sip_session_end_if_deferred(session);
if (response != 200) {
ast_sip_session_defer_termination_cancel(session);
}
return response;
}
/*! \brief Structure used to retrieve channel from another session */
struct invite_replaces {
/*! \brief Session we want the channel from */
struct ast_sip_session *session;
/*! \brief Channel from the session (with reference) */
struct ast_channel *channel;
/*! \brief Bridge the channel is in */
struct ast_bridge *bridge;
};
/*! \brief Task for invite replaces */
static int invite_replaces(void *data)
{
struct invite_replaces *invite = data;
if (!invite->session->channel) {
return -1;
}
ast_channel_ref(invite->session->channel);
invite->channel = invite->session->channel;
invite->bridge = ast_bridge_transfer_acquire_bridge(invite->channel);
return 0;
}
static int refer_incoming_invite_request(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
pjsip_dialog *other_dlg = NULL;
pjsip_tx_data *packet;
int response = 0;
RAII_VAR(struct ast_sip_session *, other_session, NULL, ao2_cleanup);
struct invite_replaces invite;
/* If a Replaces header is present make sure it is valid */
if (pjsip_replaces_verify_request(rdata, &other_dlg, PJ_TRUE, &packet) != PJ_SUCCESS) {
response = packet->msg->line.status.code;
ast_assert(response != 0);
pjsip_tx_data_dec_ref(packet);
goto inv_replace_failed;
}
/* If no other dialog exists then this INVITE request does not have a Replaces header */
if (!other_dlg) {
return 0;
}
other_session = ast_sip_dialog_get_session(other_dlg);
pjsip_dlg_dec_lock(other_dlg);
/* Don't accept an in-dialog INVITE with Replaces as it does not make much sense */
if (session->inv_session->dlg->state == PJSIP_DIALOG_STATE_ESTABLISHED) {
response = 488;
goto inv_replace_failed;
}
if (!other_session) {
ast_debug(3, "INVITE with Replaces received on channel '%s' from endpoint '%s', but requested session does not exist\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
response = 481;
goto inv_replace_failed;
}
invite.session = other_session;
if (ast_sip_push_task_wait_serializer(other_session->serializer, invite_replaces,
&invite)) {
response = 481;
goto inv_replace_failed;
}
ast_channel_lock(session->channel);
ast_setstate(session->channel, AST_STATE_RING);
ast_channel_unlock(session->channel);
ast_raw_answer(session->channel);
ast_debug(3, "INVITE with Replaces being attempted. '%s' --> '%s'\n",
ast_channel_name(session->channel), ast_channel_name(invite.channel));
if (!invite.bridge) {
struct ast_channel *chan = session->channel;
/*
* This will use a synchronous task but we aren't operating in
* the serializer at this point in time, so it won't deadlock.
*/
if (!ast_channel_move(invite.channel, chan)) {
/*
* We can't directly use session->channel because ast_channel_move()
* does a masquerade which changes session->channel to a different
* channel. To ensure we work on the right channel we store a
* pointer locally before we begin so it remains valid.
*/
ast_hangup(chan);
} else {
response = AST_CAUSE_FAILURE;
}
} else {
if (ast_bridge_impart(invite.bridge, session->channel, invite.channel, NULL,
AST_BRIDGE_IMPART_CHAN_INDEPENDENT)) {
response = AST_CAUSE_FAILURE;
}
}
ast_channel_unref(invite.channel);
ao2_cleanup(invite.bridge);
if (!response) {
/*
* On success we cannot use session->channel in the debug message.
* This thread either no longer has a ref to session->channel or
* session->channel is no longer the original channel.
*/
ast_debug(3, "INVITE with Replaces successfully completed.\n");
} else {
ast_debug(3, "INVITE with Replaces failed on channel '%s', hanging up with cause '%d'\n",
ast_channel_name(session->channel), response);
ast_channel_lock(session->channel);
ast_channel_hangupcause_set(session->channel, response);
ast_channel_unlock(session->channel);
ast_hangup(session->channel);
}
return 1;
inv_replace_failed:
if (session->inv_session->dlg->state != PJSIP_DIALOG_STATE_ESTABLISHED) {
ast_debug(3, "INVITE with Replaces failed on channel '%s', sending response of '%d'\n",
ast_channel_name(session->channel), response);
session->defer_terminate = 1;
ast_hangup(session->channel);
if (pjsip_inv_end_session(session->inv_session, response, NULL, &packet) == PJ_SUCCESS
&& packet) {
ast_sip_session_send_response(session, packet);
}
} else {
ast_debug(3, "INVITE with Replaces in-dialog on channel '%s', hanging up\n",
ast_channel_name(session->channel));
ast_queue_hangup(session->channel);
}
return 1;
}
static int refer_incoming_refer_request(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
pjsip_generic_string_hdr *refer_to;
char *uri;
size_t uri_size;
pjsip_uri *target;
pjsip_sip_uri *target_uri;
RAII_VAR(struct refer_progress *, progress, NULL, ao2_cleanup);
pjsip_param *replaces;
int response;
static const pj_str_t str_refer_to = { "Refer-To", 8 };
static const pj_str_t str_refer_to_s = { "r", 1 };
static const pj_str_t str_replaces = { "Replaces", 8 };
if (!session->channel) {
/* No channel to refer. Likely because the call was just hung up. */
pjsip_dlg_respond(session->inv_session->dlg, rdata, 404, NULL, NULL, NULL);
ast_debug(3, "Received a REFER on a session with no channel from endpoint '%s'.\n",
ast_sorcery_object_get_id(session->endpoint));
return 0;
}
if (!session->endpoint->allowtransfer) {
pjsip_dlg_respond(session->inv_session->dlg, rdata, 603, NULL, NULL, NULL);
ast_log(LOG_WARNING, "Endpoint %s transfer attempt blocked due to configuration\n",
ast_sorcery_object_get_id(session->endpoint));
return 0;
}
/* A Refer-To header is required */
refer_to = pjsip_msg_find_hdr_by_names(rdata->msg_info.msg, &str_refer_to, &str_refer_to_s, NULL);
if (!refer_to) {
pjsip_dlg_respond(session->inv_session->dlg, rdata, 400, NULL, NULL, NULL);
ast_debug(3, "Received a REFER without Refer-To on channel '%s' from endpoint '%s'\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
return 0;
}
/* The ast_copy_pj_str to uri is needed because it puts the NULL terminator to the uri
* as pjsip_parse_uri require a NULL terminated uri
*/
uri_size = pj_strlen(&refer_to->hvalue) + 1;
uri = ast_alloca(uri_size);
ast_copy_pj_str(uri, &refer_to->hvalue, uri_size);
target = pjsip_parse_uri(rdata->tp_info.pool, uri, uri_size - 1, 0);
if (!target
|| (!PJSIP_URI_SCHEME_IS_SIP(target)
&& !PJSIP_URI_SCHEME_IS_SIPS(target))) {
pjsip_dlg_respond(session->inv_session->dlg, rdata, 400, NULL, NULL, NULL);
ast_debug(3, "Received a REFER without a parseable Refer-To ('%s') on channel '%s' from endpoint '%s'\n",
uri, ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
return 0;
}
target_uri = pjsip_uri_get_uri(target);
/* Set up REFER progress subscription if requested/possible */
if (refer_progress_alloc(session, rdata, &progress)) {
pjsip_dlg_respond(session->inv_session->dlg, rdata, 500, NULL, NULL, NULL);
ast_debug(3, "Could not set up subscription for REFER on channel '%s' from endpoint '%s'\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint));
return 0;
}
/* Determine if this is an attended or blind transfer */
if ((replaces = pjsip_param_find(&target_uri->header_param, &str_replaces)) ||
(replaces = pjsip_param_find(&target_uri->other_param, &str_replaces))) {
response = refer_incoming_attended_request(session, rdata, target_uri, replaces, progress);
} else {
response = refer_incoming_blind_request(session, rdata, target_uri, progress);
}
if (!progress) {
/* The transferer has requested no subscription, so send a final response immediately */
pjsip_tx_data *tdata;
const pj_str_t str_refer_sub = { "Refer-Sub", 9 };
const pj_str_t str_false = { "false", 5 };
pjsip_hdr *hdr;
ast_debug(3, "Progress monitoring not requested for REFER on channel '%s' from endpoint '%s', sending immediate response of '%d'\n",
ast_channel_name(session->channel), ast_sorcery_object_get_id(session->endpoint), response);
if (pjsip_dlg_create_response(session->inv_session->dlg, rdata, response, NULL, &tdata) != PJ_SUCCESS) {
pjsip_dlg_respond(session->inv_session->dlg, rdata, response, NULL, NULL, NULL);
return 0;
}
hdr = (pjsip_hdr*)pjsip_generic_string_hdr_create(tdata->pool, &str_refer_sub, &str_false);
pjsip_msg_add_hdr(tdata->msg, hdr);
pjsip_dlg_send_response(session->inv_session->dlg, pjsip_rdata_get_tsx(rdata), tdata);
} else if (response != 200) {
/* Since this failed we can send a final NOTIFY now and terminate the subscription */
struct refer_progress_notification *notification = refer_progress_notification_alloc(progress, response, PJSIP_EVSUB_STATE_TERMINATED);
if (notification) {
/* The refer_progress_notify function will call ao2_cleanup on this for us */
refer_progress_notify(notification);
}
}
return 0;
}
static int refer_incoming_request(struct ast_sip_session *session, pjsip_rx_data *rdata)
{
if (!pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, pjsip_get_refer_method())) {
return refer_incoming_refer_request(session, rdata);
} else if (!pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, &pjsip_invite_method)) {
return refer_incoming_invite_request(session, rdata);
} else {
return 0;
}
}
/*!
* \brief Use the value of a channel variable as the value of a SIP header
*
* This looks up a variable name on a channel, then takes that value and adds
* it to an outgoing SIP request. If the header already exists on the message,
* then no action is taken.
*
* \pre chan is locked.
*
* \param chan The channel on which to find the variable.
* \param var_name The name of the channel variable to use.
* \param header_name The name of the SIP header to add to the outgoing message.
* \param tdata The outgoing SIP message on which to add the header
*/
static void add_header_from_channel_var(struct ast_channel *chan, const char *var_name, const char *header_name, pjsip_tx_data *tdata)
{
const char *var_value;
pj_str_t pj_header_name;
pjsip_hdr *header;
var_value = pbx_builtin_getvar_helper(chan, var_name);
if (ast_strlen_zero(var_value)) {
return;
}
pj_cstr(&pj_header_name, header_name);
header = pjsip_msg_find_hdr_by_name(tdata->msg, &pj_header_name, NULL);
if (header) {
return;
}
ast_sip_add_header(tdata, header_name, var_value);
}
static void refer_outgoing_request(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
{
if (pjsip_method_cmp(&tdata->msg->line.req.method, &pjsip_invite_method)
|| !session->channel
|| session->inv_session->state != PJSIP_INV_STATE_NULL) {
return;
}
ast_channel_lock(session->channel);
add_header_from_channel_var(session->channel, "SIPREPLACESHDR", "Replaces", tdata);
add_header_from_channel_var(session->channel, "SIPREFERREDBYHDR", "Referred-By", tdata);
ast_channel_unlock(session->channel);
}
static struct ast_sip_session_supplement refer_supplement = {
.priority = AST_SIP_SUPPLEMENT_PRIORITY_CHANNEL + 1,
.incoming_request = refer_incoming_request,
.outgoing_request = refer_outgoing_request,
};
static int load_module(void)
{
const pj_str_t str_norefersub = { "norefersub", 10 };
pjsip_replaces_init_module(ast_sip_get_pjsip_endpoint());
pjsip_xfer_init_module(ast_sip_get_pjsip_endpoint());
if (ast_sip_get_norefersub()) {
pjsip_endpt_add_capability(ast_sip_get_pjsip_endpoint(), NULL, PJSIP_H_SUPPORTED, NULL, 1, &str_norefersub);
}
ast_sip_register_service(&refer_progress_module);
ast_sip_session_register_supplement(&refer_supplement);
ast_module_shutdown_ref(ast_module_info->self);
return AST_MODULE_LOAD_SUCCESS;
}
static int unload_module(void)
{
ast_sip_session_unregister_supplement(&refer_supplement);
ast_sip_unregister_service(&refer_progress_module);
return 0;
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Blind and Attended Transfer Support",
.support_level = AST_MODULE_SUPPORT_CORE,
.load = load_module,
.unload = unload_module,
.load_pri = AST_MODPRI_APP_DEPEND,
.requires = "res_pjsip,res_pjsip_session,res_pjsip_pubsub",
);
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