asterisk/res/res_pjsip_t38.c

1172 lines
40 KiB
C

/*
* 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.
*/
/*! \file
*
* \author Joshua Colp <jcolp@digium.com>
*
* \brief SIP T.38 handling
*/
/*** 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 <pjmedia.h>
#include <pjlib.h>
#include "asterisk/utils.h"
#include "asterisk/module.h"
#include "asterisk/udptl.h"
#include "asterisk/netsock2.h"
#include "asterisk/channel.h"
#include "asterisk/acl.h"
#include "asterisk/stream.h"
#include "asterisk/format_cache.h"
#include "asterisk/res_pjsip.h"
#include "asterisk/res_pjsip_session.h"
/*! \brief The number of seconds after receiving a T.38 re-invite before automatically rejecting it */
#define T38_AUTOMATIC_REJECTION_SECONDS 5
/*! \brief Address for UDPTL */
static struct ast_sockaddr address;
/*! \brief T.38 state information */
struct t38_state {
/*! \brief Current state */
enum ast_sip_session_t38state state;
/*! \brief Our T.38 parameters */
struct ast_control_t38_parameters our_parms;
/*! \brief Their T.38 parameters */
struct ast_control_t38_parameters their_parms;
/*! \brief Timer entry for automatically rejecting an inbound re-invite */
pj_timer_entry timer;
/*! Preserved media state for when T.38 ends */
struct ast_sip_session_media_state *media_state;
};
/*! \brief Destructor for T.38 state information */
static void t38_state_destroy(void *obj)
{
struct t38_state *state = obj;
ast_sip_session_media_state_free(state->media_state);
ast_free(obj);
}
/*! \brief Datastore for attaching T.38 state information */
static const struct ast_datastore_info t38_datastore = {
.type = "t38",
.destroy = t38_state_destroy,
};
/*! \brief Structure for T.38 parameters task data */
struct t38_parameters_task_data {
/*! \brief Session itself */
struct ast_sip_session *session;
/*! \brief T.38 control frame */
struct ast_frame *frame;
};
/*! \brief Destructor for T.38 data */
static void t38_parameters_task_data_destroy(void *obj)
{
struct t38_parameters_task_data *data = obj;
ao2_cleanup(data->session);
if (data->frame) {
ast_frfree(data->frame);
}
}
/*! \brief Allocator for T.38 data */
static struct t38_parameters_task_data *t38_parameters_task_data_alloc(struct ast_sip_session *session,
struct ast_frame *frame)
{
struct t38_parameters_task_data *data = ao2_alloc(sizeof(*data), t38_parameters_task_data_destroy);
if (!data) {
return NULL;
}
data->session = session;
ao2_ref(session, +1);
data->frame = ast_frdup(frame);
if (!data->frame) {
ao2_ref(data, -1);
data = NULL;
}
return data;
}
/*! \brief Helper function for changing the T.38 state */
static void t38_change_state(struct ast_sip_session *session, struct ast_sip_session_media *session_media,
struct t38_state *state, enum ast_sip_session_t38state new_state)
{
enum ast_sip_session_t38state old_state = session->t38state;
struct ast_control_t38_parameters parameters = { .request_response = 0, };
pj_time_val delay = { .sec = T38_AUTOMATIC_REJECTION_SECONDS };
if (old_state == new_state) {
return;
}
session->t38state = new_state;
ast_debug(2, "T.38 state changed to '%u' from '%u' on channel '%s'\n",
new_state, old_state,
session->channel ? ast_channel_name(session->channel) : "<gone>");
if (pj_timer_heap_cancel_if_active(pjsip_endpt_get_timer_heap(ast_sip_get_pjsip_endpoint()),
&state->timer, 0)) {
ast_debug(2, "Automatic T.38 rejection on channel '%s' terminated\n",
session->channel ? ast_channel_name(session->channel) : "<gone>");
ao2_ref(session, -1);
}
if (!session->channel) {
return;
}
switch (new_state) {
case T38_PEER_REINVITE:
ao2_ref(session, +1);
if (pjsip_endpt_schedule_timer(ast_sip_get_pjsip_endpoint(), &state->timer, &delay) != PJ_SUCCESS) {
ast_log(LOG_WARNING, "Scheduling of automatic T.38 rejection for channel '%s' failed\n",
ast_channel_name(session->channel));
ao2_ref(session, -1);
}
parameters = state->their_parms;
parameters.max_ifp = ast_udptl_get_far_max_ifp(session_media->udptl);
parameters.request_response = AST_T38_REQUEST_NEGOTIATE;
ast_udptl_set_tag(session_media->udptl, "%s", ast_channel_name(session->channel));
/* Inform the bridge the channel is in that it needs to be reconfigured */
ast_channel_set_unbridged(session->channel, 1);
break;
case T38_ENABLED:
parameters = state->their_parms;
parameters.max_ifp = ast_udptl_get_far_max_ifp(session_media->udptl);
parameters.request_response = AST_T38_NEGOTIATED;
ast_udptl_set_tag(session_media->udptl, "%s", ast_channel_name(session->channel));
break;
case T38_REJECTED:
case T38_DISABLED:
if (old_state == T38_ENABLED) {
parameters.request_response = AST_T38_TERMINATED;
} else if (old_state == T38_LOCAL_REINVITE) {
parameters.request_response = AST_T38_REFUSED;
}
break;
case T38_LOCAL_REINVITE:
/* Inform the bridge the channel is in that it needs to be reconfigured */
ast_channel_set_unbridged(session->channel, 1);
break;
case T38_MAX_ENUM:
/* Well, that shouldn't happen */
ast_assert(0);
break;
}
if (parameters.request_response) {
ast_queue_control_data(session->channel, AST_CONTROL_T38_PARAMETERS, &parameters, sizeof(parameters));
}
}
/*! \brief Task function which rejects a T.38 re-invite and resumes handling it */
static int t38_automatic_reject(void *obj)
{
RAII_VAR(struct ast_sip_session *, session, obj, ao2_cleanup);
RAII_VAR(struct ast_datastore *, datastore, ast_sip_session_get_datastore(session, "t38"), ao2_cleanup);
if (!datastore) {
return 0;
}
ast_debug(2, "Automatically rejecting T.38 request on channel '%s'\n",
session->channel ? ast_channel_name(session->channel) : "<gone>");
t38_change_state(session, NULL, datastore->data, T38_REJECTED);
ast_sip_session_resume_reinvite(session);
return 0;
}
/*! \brief Timer entry callback which queues a task to reject a T.38 re-invite and resume handling it */
static void t38_automatic_reject_timer_cb(pj_timer_heap_t *timer_heap, struct pj_timer_entry *entry)
{
struct ast_sip_session *session = entry->user_data;
if (ast_sip_push_task(session->serializer, t38_automatic_reject, session)) {
ao2_ref(session, -1);
}
}
/*! \brief Helper function which retrieves or allocates a T.38 state information datastore */
static struct t38_state *t38_state_get_or_alloc(struct ast_sip_session *session)
{
RAII_VAR(struct ast_datastore *, datastore, ast_sip_session_get_datastore(session, "t38"), ao2_cleanup);
struct t38_state *state;
/* While the datastore refcount is decremented this is operating in the serializer so it will remain valid regardless */
if (datastore) {
return datastore->data;
}
if (!(datastore = ast_sip_session_alloc_datastore(&t38_datastore, "t38"))
|| !(datastore->data = ast_calloc(1, sizeof(struct t38_state)))
|| ast_sip_session_add_datastore(session, datastore)) {
return NULL;
}
state = datastore->data;
/* This will get bumped up before scheduling */
pj_timer_entry_init(&state->timer, 0, session, t38_automatic_reject_timer_cb);
return state;
}
/*! \brief Initializes UDPTL support on a session, only done when actually needed */
static int t38_initialize_session(struct ast_sip_session *session, struct ast_sip_session_media *session_media)
{
struct ast_sockaddr temp_media_address;
struct ast_sockaddr *media_address = &address;
if (session_media->udptl) {
return 0;
}
if (session->endpoint->media.t38.bind_udptl_to_media_address && !ast_strlen_zero(session->endpoint->media.address)) {
if (ast_sockaddr_parse(&temp_media_address, session->endpoint->media.address, 0)) {
ast_debug(5, "Endpoint %s: Binding UDPTL media to %s\n",
ast_sorcery_object_get_id(session->endpoint),
session->endpoint->media.address);
media_address = &temp_media_address;
} else {
ast_debug(5, "Endpoint %s: UDPTL media address invalid: %s\n",
ast_sorcery_object_get_id(session->endpoint),
session->endpoint->media.address);
}
} else {
struct ast_sip_transport *transport;
transport = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "transport",
session->endpoint->transport);
if (transport) {
struct ast_sip_transport_state *trans_state;
trans_state = ast_sip_get_transport_state(ast_sorcery_object_get_id(transport));
if (trans_state) {
char hoststr[PJ_INET6_ADDRSTRLEN];
pj_sockaddr_print(&trans_state->host, hoststr, sizeof(hoststr), 0);
if (ast_sockaddr_parse(&temp_media_address, hoststr, 0)) {
ast_debug(5, "Transport %s bound to %s: Using it for UDPTL media.\n",
session->endpoint->transport, hoststr);
media_address = &temp_media_address;
} else {
ast_debug(5, "Transport %s bound to %s: Invalid for UDPTL media.\n",
session->endpoint->transport, hoststr);
}
ao2_ref(trans_state, -1);
}
ao2_ref(transport, -1);
}
}
if (!(session_media->udptl = ast_udptl_new_with_bindaddr(NULL, NULL, 0, media_address))) {
return -1;
}
ast_udptl_set_error_correction_scheme(session_media->udptl, session->endpoint->media.t38.error_correction);
ast_udptl_setnat(session_media->udptl, session->endpoint->media.t38.nat);
ast_udptl_set_far_max_datagram(session_media->udptl, session->endpoint->media.t38.maxdatagram);
ast_debug(3, "UDPTL initialized on session for %s\n", ast_channel_name(session->channel));
return 0;
}
/*! \brief Callback for when T.38 reinvite SDP is created */
static int t38_reinvite_sdp_cb(struct ast_sip_session *session, pjmedia_sdp_session *sdp)
{
struct t38_state *state;
state = t38_state_get_or_alloc(session);
if (!state) {
return -1;
}
state->media_state = ast_sip_session_media_state_clone(session->active_media_state);
return 0;
}
/*! \brief Callback for when a response is received for a T.38 re-invite */
static int t38_reinvite_response_cb(struct ast_sip_session *session, pjsip_rx_data *rdata)
{
struct pjsip_status_line status = rdata->msg_info.msg->line.status;
struct t38_state *state;
struct ast_sip_session_media *session_media = NULL;
if (status.code / 100 <= 1) {
/* Ignore any non-final responses (1xx) */
return 0;
}
if (session->t38state != T38_LOCAL_REINVITE) {
/* Do nothing. We have already processed a final response. */
ast_debug(3, "Received %d response to T.38 re-invite on '%s' but already had a final response (T.38 state:%d)\n",
status.code,
session->channel ? ast_channel_name(session->channel) : "unknown channel",
session->t38state);
return 0;
}
state = t38_state_get_or_alloc(session);
if (!session->channel || !state) {
ast_log(LOG_WARNING, "Received %d response to T.38 re-invite on '%s' but state unavailable\n",
status.code,
session->channel ? ast_channel_name(session->channel) : "unknown channel");
return 0;
}
if (status.code / 100 == 2) {
/* Accept any 2xx response as successfully negotiated */
int index;
session_media = session->active_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
/*
* If there is a session_media object, but no udptl object available
* then it's assumed the stream was declined.
*/
if (session_media && !session_media->udptl) {
session_media = NULL;
}
if (!session_media) {
ast_log(LOG_WARNING, "Received %d response to T.38 re-invite on '%s' but no active session media\n",
status.code, session->channel ? ast_channel_name(session->channel) : "unknown channel");
} else {
t38_change_state(session, session_media, state, T38_ENABLED);
/* Stop all the streams in the stored away active state, they'll go back to being active once
* we reinvite back.
*/
for (index = 0; index < AST_VECTOR_SIZE(&state->media_state->sessions); ++index) {
struct ast_sip_session_media *session_media = AST_VECTOR_GET(&state->media_state->sessions, index);
if (session_media && session_media->handler && session_media->handler->stream_stop) {
session_media->handler->stream_stop(session_media);
}
}
return 0;
}
} else {
session_media = session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
}
/* If no session_media then response contained a declined stream, so disable */
t38_change_state(session, NULL, state, session_media ? T38_REJECTED : T38_DISABLED);
/* Abort this attempt at switching to T.38 by resetting the pending state and freeing our stored away active state */
ast_sip_session_media_state_free(state->media_state);
state->media_state = NULL;
ast_sip_session_media_state_reset(session->pending_media_state);
return 0;
}
/*! \brief Helper function which creates a media state for strictly T.38 */
static struct ast_sip_session_media_state *t38_create_media_state(struct ast_sip_session *session)
{
struct ast_sip_session_media_state *media_state;
struct ast_stream *stream;
struct ast_format_cap *caps;
struct ast_sip_session_media *session_media;
media_state = ast_sip_session_media_state_alloc();
if (!media_state) {
return NULL;
}
media_state->topology = ast_stream_topology_alloc();
if (!media_state->topology) {
ast_sip_session_media_state_free(media_state);
return NULL;
}
stream = ast_stream_alloc("t38", AST_MEDIA_TYPE_IMAGE);
if (!stream) {
ast_sip_session_media_state_free(media_state);
return NULL;
}
ast_stream_set_state(stream, AST_STREAM_STATE_SENDRECV);
if (ast_stream_topology_set_stream(media_state->topology, 0, stream)) {
ast_stream_free(stream);
ast_sip_session_media_state_free(media_state);
return NULL;
}
caps = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
if (!caps) {
ast_sip_session_media_state_free(media_state);
return NULL;
}
ast_stream_set_formats(stream, caps);
/* stream holds a reference to cap, release the local reference
* now so we don't have to deal with it in the error condition. */
ao2_ref(caps, -1);
if (ast_format_cap_append(caps, ast_format_t38, 0)) {
ast_sip_session_media_state_free(media_state);
return NULL;
}
session_media = ast_sip_session_media_state_add(session, media_state, AST_MEDIA_TYPE_IMAGE, 0);
if (!session_media) {
ast_sip_session_media_state_free(media_state);
return NULL;
}
if (t38_initialize_session(session, session_media)) {
ast_sip_session_media_state_free(media_state);
return NULL;
}
return media_state;
}
/*! \brief Task for reacting to T.38 control frame */
static int t38_interpret_parameters(void *obj)
{
RAII_VAR(struct t38_parameters_task_data *, data, obj, ao2_cleanup);
const struct ast_control_t38_parameters *parameters = data->frame->data.ptr;
struct t38_state *state = t38_state_get_or_alloc(data->session);
struct ast_sip_session_media *session_media = NULL;
if (!state) {
return 0;
}
switch (parameters->request_response) {
case AST_T38_NEGOTIATED:
case AST_T38_REQUEST_NEGOTIATE: /* Request T38 */
/* Negotiation can not take place without a valid max_ifp value. */
if (!parameters->max_ifp) {
if (data->session->t38state == T38_PEER_REINVITE) {
t38_change_state(data->session, NULL, state, T38_REJECTED);
ast_sip_session_resume_reinvite(data->session);
} else if (data->session->t38state == T38_ENABLED) {
t38_change_state(data->session, NULL, state, T38_DISABLED);
ast_sip_session_refresh(data->session, NULL, NULL, NULL,
AST_SIP_SESSION_REFRESH_METHOD_INVITE, 1, state->media_state);
state->media_state = NULL;
}
break;
} else if (data->session->t38state == T38_PEER_REINVITE) {
state->our_parms = *parameters;
/* modify our parameters to conform to the peer's parameters,
* based on the rules in the ITU T.38 recommendation
*/
if (!state->their_parms.fill_bit_removal) {
state->our_parms.fill_bit_removal = 0;
}
if (!state->their_parms.transcoding_mmr) {
state->our_parms.transcoding_mmr = 0;
}
if (!state->their_parms.transcoding_jbig) {
state->our_parms.transcoding_jbig = 0;
}
state->our_parms.version = MIN(state->our_parms.version, state->their_parms.version);
state->our_parms.rate_management = state->their_parms.rate_management;
session_media = data->session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
if (!session_media) {
ast_log(LOG_ERROR, "Failed to negotiate parameters for reinvite on channel '%s' (No pending session media).\n",
data->session->channel ? ast_channel_name(data->session->channel) : "unknown channel");
break;
}
ast_udptl_set_local_max_ifp(session_media->udptl, state->our_parms.max_ifp);
t38_change_state(data->session, session_media, state, T38_ENABLED);
ast_sip_session_resume_reinvite(data->session);
} else if ((data->session->t38state != T38_ENABLED) ||
((data->session->t38state == T38_ENABLED) &&
(parameters->request_response == AST_T38_REQUEST_NEGOTIATE))) {
struct ast_sip_session_media_state *media_state;
media_state = t38_create_media_state(data->session);
if (!media_state) {
break;
}
state->our_parms = *parameters;
session_media = media_state->default_session[AST_MEDIA_TYPE_IMAGE];
if (!session_media) {
ast_log(LOG_ERROR, "Failed to negotiate parameters on channel '%s' (No default session media).\n",
data->session->channel ? ast_channel_name(data->session->channel) : "unknown channel");
break;
}
ast_udptl_set_local_max_ifp(session_media->udptl, state->our_parms.max_ifp);
t38_change_state(data->session, NULL, state, T38_LOCAL_REINVITE);
ast_sip_session_refresh(data->session, NULL, t38_reinvite_sdp_cb, t38_reinvite_response_cb,
AST_SIP_SESSION_REFRESH_METHOD_INVITE, 1, media_state);
}
break;
case AST_T38_TERMINATED:
case AST_T38_REFUSED:
case AST_T38_REQUEST_TERMINATE: /* Shutdown T38 */
if (data->session->t38state == T38_PEER_REINVITE) {
t38_change_state(data->session, NULL, state, T38_REJECTED);
ast_sip_session_resume_reinvite(data->session);
} else if (data->session->t38state == T38_ENABLED) {
t38_change_state(data->session, NULL, state, T38_DISABLED);
ast_sip_session_refresh(data->session, NULL, NULL, NULL, AST_SIP_SESSION_REFRESH_METHOD_INVITE, 1, state->media_state);
state->media_state = NULL;
}
break;
case AST_T38_REQUEST_PARMS: { /* Application wants remote's parameters re-sent */
struct ast_control_t38_parameters parameters = state->their_parms;
if (data->session->t38state == T38_PEER_REINVITE) {
session_media = data->session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
if (!session_media) {
ast_log(LOG_ERROR, "Failed to request parameters for reinvite on channel '%s' (No pending session media).\n",
data->session->channel ? ast_channel_name(data->session->channel) : "unknown channel");
break;
}
parameters.max_ifp = ast_udptl_get_far_max_ifp(session_media->udptl);
parameters.request_response = AST_T38_REQUEST_NEGOTIATE;
ast_queue_control_data(data->session->channel, AST_CONTROL_T38_PARAMETERS, &parameters, sizeof(parameters));
}
break;
}
default:
break;
}
return 0;
}
/*! \brief Frame hook callback for T.38 related stuff */
static struct ast_frame *t38_framehook(struct ast_channel *chan, struct ast_frame *f,
enum ast_framehook_event event, void *data)
{
struct ast_sip_channel_pvt *channel = ast_channel_tech_pvt(chan);
if (event != AST_FRAMEHOOK_EVENT_WRITE) {
return f;
}
if (f->frametype == AST_FRAME_CONTROL
&& f->subclass.integer == AST_CONTROL_T38_PARAMETERS) {
if (channel->session->endpoint->media.t38.enabled) {
struct t38_parameters_task_data *task_data;
task_data = t38_parameters_task_data_alloc(channel->session, f);
if (task_data
&& ast_sip_push_task(channel->session->serializer,
t38_interpret_parameters, task_data)) {
ao2_ref(task_data, -1);
}
} else {
static const struct ast_control_t38_parameters rsp_refused = {
.request_response = AST_T38_REFUSED,
};
static const struct ast_control_t38_parameters rsp_terminated = {
.request_response = AST_T38_TERMINATED,
};
const struct ast_control_t38_parameters *parameters = f->data.ptr;
switch (parameters->request_response) {
case AST_T38_REQUEST_NEGOTIATE:
ast_debug(2, "T.38 support not enabled on %s, refusing T.38 negotiation\n",
ast_channel_name(chan));
ast_queue_control_data(chan, AST_CONTROL_T38_PARAMETERS,
&rsp_refused, sizeof(rsp_refused));
break;
case AST_T38_REQUEST_TERMINATE:
ast_debug(2, "T.38 support not enabled on %s, 'terminating' T.38 session\n",
ast_channel_name(chan));
ast_queue_control_data(chan, AST_CONTROL_T38_PARAMETERS,
&rsp_terminated, sizeof(rsp_terminated));
break;
default:
break;
}
}
}
return f;
}
static void t38_masq(void *data, int framehook_id,
struct ast_channel *old_chan, struct ast_channel *new_chan)
{
if (ast_channel_tech(old_chan) == ast_channel_tech(new_chan)) {
return;
}
/* This framehook is only applicable to PJSIP channels */
ast_framehook_detach(new_chan, framehook_id);
}
static int t38_consume(void *data, enum ast_frame_type type)
{
return (type == AST_FRAME_CONTROL) ? 1 : 0;
}
static const struct ast_datastore_info t38_framehook_datastore = {
.type = "T38 framehook",
};
/*! \brief Function called to attach T.38 framehook to channel when appropriate */
static void t38_attach_framehook(struct ast_sip_session *session)
{
int framehook_id;
struct ast_datastore *datastore = NULL;
static struct ast_framehook_interface hook = {
.version = AST_FRAMEHOOK_INTERFACE_VERSION,
.event_cb = t38_framehook,
.consume_cb = t38_consume,
.chan_fixup_cb = t38_masq,
.chan_breakdown_cb = t38_masq,
};
/* If the channel's already gone, bail */
if (!session->channel) {
return;
}
/* Always attach the framehook so we can quickly reject */
ast_channel_lock(session->channel);
/* Skip attaching the framehook if the T.38 datastore already exists for the channel */
datastore = ast_channel_datastore_find(session->channel, &t38_framehook_datastore,
NULL);
if (datastore) {
ast_channel_unlock(session->channel);
return;
}
framehook_id = ast_framehook_attach(session->channel, &hook);
if (framehook_id < 0) {
ast_log(LOG_WARNING, "Could not attach T.38 Frame hook, T.38 will be unavailable on '%s'\n",
ast_channel_name(session->channel));
ast_channel_unlock(session->channel);
return;
}
datastore = ast_datastore_alloc(&t38_framehook_datastore, NULL);
if (!datastore) {
ast_log(LOG_ERROR, "Could not alloc T.38 Frame hook datastore, T.38 will be unavailable on '%s'\n",
ast_channel_name(session->channel));
ast_framehook_detach(session->channel, framehook_id);
ast_channel_unlock(session->channel);
return;
}
ast_channel_datastore_add(session->channel, datastore);
ast_channel_unlock(session->channel);
}
/*! \brief Function called when an INVITE arrives */
static int t38_incoming_invite_request(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
t38_attach_framehook(session);
return 0;
}
/*! \brief Function called when an INVITE is sent */
static void t38_outgoing_invite_request(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
{
t38_attach_framehook(session);
}
/*! \brief Get Max T.38 Transmission rate from T38 capabilities */
static unsigned int t38_get_rate(enum ast_control_t38_rate rate)
{
switch (rate) {
case AST_T38_RATE_2400:
return 2400;
case AST_T38_RATE_4800:
return 4800;
case AST_T38_RATE_7200:
return 7200;
case AST_T38_RATE_9600:
return 9600;
case AST_T38_RATE_12000:
return 12000;
case AST_T38_RATE_14400:
return 14400;
default:
return 0;
}
}
/*! \brief Supplement for adding framehook to session channel */
static struct ast_sip_session_supplement t38_supplement = {
.method = "INVITE",
.priority = AST_SIP_SUPPLEMENT_PRIORITY_CHANNEL + 1,
.incoming_request = t38_incoming_invite_request,
.outgoing_request = t38_outgoing_invite_request,
};
/*! \brief Parse a T.38 image stream and store the attribute information */
static void t38_interpret_sdp(struct t38_state *state, struct ast_sip_session *session, struct ast_sip_session_media *session_media,
const struct pjmedia_sdp_media *stream)
{
unsigned int attr_i;
for (attr_i = 0; attr_i < stream->attr_count; attr_i++) {
pjmedia_sdp_attr *attr = stream->attr[attr_i];
if (!pj_stricmp2(&attr->name, "t38faxmaxbuffer")) {
/* This is purposely left empty, it is unused */
} else if (!pj_stricmp2(&attr->name, "t38maxbitrate") || !pj_stricmp2(&attr->name, "t38faxmaxrate")) {
switch (pj_strtoul(&attr->value)) {
case 14400:
state->their_parms.rate = AST_T38_RATE_14400;
break;
case 12000:
state->their_parms.rate = AST_T38_RATE_12000;
break;
case 9600:
state->their_parms.rate = AST_T38_RATE_9600;
break;
case 7200:
state->their_parms.rate = AST_T38_RATE_7200;
break;
case 4800:
state->their_parms.rate = AST_T38_RATE_4800;
break;
case 2400:
state->their_parms.rate = AST_T38_RATE_2400;
break;
}
} else if (!pj_stricmp2(&attr->name, "t38faxversion")) {
state->their_parms.version = pj_strtoul(&attr->value);
} else if (!pj_stricmp2(&attr->name, "t38faxmaxdatagram") || !pj_stricmp2(&attr->name, "t38maxdatagram")) {
if (!session->endpoint->media.t38.maxdatagram) {
ast_udptl_set_far_max_datagram(session_media->udptl, pj_strtoul(&attr->value));
}
} else if (!pj_stricmp2(&attr->name, "t38faxfillbitremoval")) {
state->their_parms.fill_bit_removal = 1;
} else if (!pj_stricmp2(&attr->name, "t38faxtranscodingmmr")) {
state->their_parms.transcoding_mmr = 1;
} else if (!pj_stricmp2(&attr->name, "t38faxtranscodingjbig")) {
state->their_parms.transcoding_jbig = 1;
} else if (!pj_stricmp2(&attr->name, "t38faxratemanagement")) {
if (!pj_stricmp2(&attr->value, "localTCF")) {
state->their_parms.rate_management = AST_T38_RATE_MANAGEMENT_LOCAL_TCF;
} else if (!pj_stricmp2(&attr->value, "transferredTCF")) {
state->their_parms.rate_management = AST_T38_RATE_MANAGEMENT_TRANSFERRED_TCF;
}
} else if (!pj_stricmp2(&attr->name, "t38faxudpec")) {
if (session->t38state == T38_LOCAL_REINVITE) {
if (session->endpoint->media.t38.error_correction == UDPTL_ERROR_CORRECTION_FEC) {
if (!pj_stricmp2(&attr->value, "t38UDPFEC")) {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_FEC);
} else if (!pj_stricmp2(&attr->value, "t38UDPRedundancy")) {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_REDUNDANCY);
} else {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_NONE);
}
} else if (session->endpoint->media.t38.error_correction == UDPTL_ERROR_CORRECTION_REDUNDANCY) {
if (!pj_stricmp2(&attr->value, "t38UDPRedundancy")) {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_REDUNDANCY);
} else {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_NONE);
}
} else {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_NONE);
}
} else {
if (!pj_stricmp2(&attr->value, "t38UDPRedundancy")) {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_REDUNDANCY);
} else if (!pj_stricmp2(&attr->value, "t38UDPFEC")) {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_FEC);
} else {
ast_udptl_set_error_correction_scheme(session_media->udptl, UDPTL_ERROR_CORRECTION_NONE);
}
}
}
}
}
/*! \brief Function which defers an incoming media stream */
static enum ast_sip_session_sdp_stream_defer defer_incoming_sdp_stream(
struct ast_sip_session *session, struct ast_sip_session_media *session_media,
const struct pjmedia_sdp_session *sdp, const struct pjmedia_sdp_media *stream)
{
struct t38_state *state;
if (!session->endpoint->media.t38.enabled) {
ast_debug(3, "Not deferring incoming SDP stream: T.38 not enabled on %s\n", ast_channel_name(session->channel));
return AST_SIP_SESSION_SDP_DEFER_NOT_HANDLED;
}
if (t38_initialize_session(session, session_media)) {
ast_debug(3, "Not deferring incoming SDP stream: Failed to initialize UDPTL on %s\n", ast_channel_name(session->channel));
return AST_SIP_SESSION_SDP_DEFER_ERROR;
}
if (!(state = t38_state_get_or_alloc(session))) {
return AST_SIP_SESSION_SDP_DEFER_ERROR;
}
t38_interpret_sdp(state, session, session_media, stream);
/* If they are initiating the re-invite we need to defer responding until later */
if (session->t38state == T38_DISABLED) {
t38_change_state(session, session_media, state, T38_PEER_REINVITE);
ast_debug(3, "Deferring incoming SDP stream on %s for peer re-invite\n", ast_channel_name(session->channel));
return AST_SIP_SESSION_SDP_DEFER_NEEDED;
}
return AST_SIP_SESSION_SDP_DEFER_NOT_NEEDED;
}
/*! \brief Function which negotiates an incoming media stream */
static int negotiate_incoming_sdp_stream(struct ast_sip_session *session,
struct ast_sip_session_media *session_media, const struct pjmedia_sdp_session *sdp,
int index, struct ast_stream *asterisk_stream)
{
struct t38_state *state;
char host[NI_MAXHOST];
pjmedia_sdp_media *stream = sdp->media[index];
RAII_VAR(struct ast_sockaddr *, addrs, NULL, ast_free);
if (!session->endpoint->media.t38.enabled) {
ast_debug(3, "Declining; T.38 not enabled on session\n");
return 0;
}
if (!(state = t38_state_get_or_alloc(session))) {
return 0;
}
if ((session->t38state == T38_REJECTED) || (session->t38state == T38_DISABLED)) {
ast_debug(3, "Declining; T.38 state is rejected or declined\n");
t38_change_state(session, NULL, state, T38_DISABLED);
return 0;
}
ast_copy_pj_str(host, stream->conn ? &stream->conn->addr : &sdp->conn->addr, sizeof(host));
/* Ensure that the address provided is valid */
if (ast_sockaddr_resolve(&addrs, host, PARSE_PORT_FORBID, AST_AF_INET) <= 0) {
/* The provided host was actually invalid so we error out this negotiation */
ast_debug(3, "Declining; provided host is invalid\n");
return 0;
}
/* Check the address family to make sure it matches configured */
if ((ast_sockaddr_is_ipv6(addrs) && !session->endpoint->media.t38.ipv6) ||
(ast_sockaddr_is_ipv4(addrs) && session->endpoint->media.t38.ipv6)) {
/* The address does not match configured */
ast_debug(3, "Declining, provided host does not match configured address family\n");
return 0;
}
return 1;
}
/*! \brief Function which creates an outgoing stream */
static int create_outgoing_sdp_stream(struct ast_sip_session *session, struct ast_sip_session_media *session_media,
struct pjmedia_sdp_session *sdp, const struct pjmedia_sdp_session *remote, struct ast_stream *stream)
{
pj_pool_t *pool = session->inv_session->pool_prov;
static const pj_str_t STR_IN = { "IN", 2 };
static const pj_str_t STR_IP4 = { "IP4", 3};
static const pj_str_t STR_IP6 = { "IP6", 3};
static const pj_str_t STR_UDPTL = { "udptl", 5 };
static const pj_str_t STR_T38 = { "t38", 3 };
static const pj_str_t STR_TRANSFERREDTCF = { "transferredTCF", 14 };
static const pj_str_t STR_LOCALTCF = { "localTCF", 8 };
static const pj_str_t STR_T38UDPFEC = { "t38UDPFEC", 9 };
static const pj_str_t STR_T38UDPREDUNDANCY = { "t38UDPRedundancy", 16 };
struct t38_state *state;
pjmedia_sdp_media *media;
const char *hostip = NULL;
struct ast_sockaddr addr;
char tmp[512];
pj_str_t stmp;
if (!session->endpoint->media.t38.enabled) {
ast_debug(3, "Not creating outgoing SDP stream: T.38 not enabled\n");
return 1;
} else if ((session->t38state != T38_LOCAL_REINVITE) && (session->t38state != T38_PEER_REINVITE) &&
(session->t38state != T38_ENABLED)) {
ast_debug(3, "Not creating outgoing SDP stream: T.38 not enabled\n");
return 1;
} else if (!(state = t38_state_get_or_alloc(session))) {
return -1;
} else if (t38_initialize_session(session, session_media)) {
ast_debug(3, "Not creating outgoing SDP stream: Failed to initialize T.38 session\n");
return -1;
}
if (!(media = pj_pool_zalloc(pool, sizeof(struct pjmedia_sdp_media))) ||
!(media->conn = pj_pool_zalloc(pool, sizeof(struct pjmedia_sdp_conn)))) {
return -1;
}
pj_strdup2(pool, &media->desc.media, ast_codec_media_type2str(session_media->type));
media->desc.transport = STR_UDPTL;
if (ast_strlen_zero(session->endpoint->media.address)) {
hostip = ast_sip_get_host_ip_string(session->endpoint->media.t38.ipv6 ? pj_AF_INET6() : pj_AF_INET());
} else {
hostip = session->endpoint->media.address;
}
if (ast_strlen_zero(hostip)) {
ast_debug(3, "Not creating outgoing SDP stream: no known host IP\n");
return -1;
}
media->conn->net_type = STR_IN;
media->conn->addr_type = session->endpoint->media.t38.ipv6 ? STR_IP6 : STR_IP4;
pj_strdup2(pool, &media->conn->addr, hostip);
ast_udptl_get_us(session_media->udptl, &addr);
media->desc.port = (pj_uint16_t) ast_sockaddr_port(&addr);
media->desc.port_count = 1;
media->desc.fmt[media->desc.fmt_count++] = STR_T38;
snprintf(tmp, sizeof(tmp), "%u", state->our_parms.version);
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxVersion", pj_cstr(&stmp, tmp));
snprintf(tmp, sizeof(tmp), "%u", t38_get_rate(state->our_parms.rate));
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38MaxBitRate", pj_cstr(&stmp, tmp));
if (state->our_parms.fill_bit_removal) {
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxFillBitRemoval", NULL);
}
if (state->our_parms.transcoding_mmr) {
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxTranscodingMMR", NULL);
}
if (state->our_parms.transcoding_jbig) {
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxTranscodingJBIG", NULL);
}
switch (state->our_parms.rate_management) {
case AST_T38_RATE_MANAGEMENT_TRANSFERRED_TCF:
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxRateManagement", &STR_TRANSFERREDTCF);
break;
case AST_T38_RATE_MANAGEMENT_LOCAL_TCF:
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxRateManagement", &STR_LOCALTCF);
break;
}
snprintf(tmp, sizeof(tmp), "%u", ast_udptl_get_local_max_datagram(session_media->udptl));
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxMaxDatagram", pj_cstr(&stmp, tmp));
switch (ast_udptl_get_error_correction_scheme(session_media->udptl)) {
case UDPTL_ERROR_CORRECTION_NONE:
break;
case UDPTL_ERROR_CORRECTION_FEC:
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxUdpEC", &STR_T38UDPFEC);
break;
case UDPTL_ERROR_CORRECTION_REDUNDANCY:
media->attr[media->attr_count++] = pjmedia_sdp_attr_create(pool, "T38FaxUdpEC", &STR_T38UDPREDUNDANCY);
break;
}
sdp->media[sdp->media_count++] = media;
return 1;
}
static struct ast_frame *media_session_udptl_read_callback(struct ast_sip_session *session, struct ast_sip_session_media *session_media)
{
struct ast_frame *frame;
if (!session_media->udptl) {
return &ast_null_frame;
}
frame = ast_udptl_read(session_media->udptl);
if (!frame) {
return NULL;
}
frame->stream_num = session_media->stream_num;
return frame;
}
static int media_session_udptl_write_callback(struct ast_sip_session *session, struct ast_sip_session_media *session_media, struct ast_frame *frame)
{
if (!session_media->udptl) {
return 0;
}
return ast_udptl_write(session_media->udptl, frame);
}
/*! \brief Function which applies a negotiated stream */
static int apply_negotiated_sdp_stream(struct ast_sip_session *session,
struct ast_sip_session_media *session_media, const struct pjmedia_sdp_session *local,
const struct pjmedia_sdp_session *remote, int index, struct ast_stream *asterisk_stream)
{
RAII_VAR(struct ast_sockaddr *, addrs, NULL, ast_free);
pjmedia_sdp_media *remote_stream = remote->media[index];
char host[NI_MAXHOST];
struct t38_state *state;
if (!session_media->udptl) {
ast_debug(3, "Not applying negotiated SDP stream: no UDTPL session\n");
return 0;
}
if (!(state = t38_state_get_or_alloc(session))) {
return -1;
}
ast_copy_pj_str(host, remote_stream->conn ? &remote_stream->conn->addr : &remote->conn->addr, sizeof(host));
/* Ensure that the address provided is valid */
if (ast_sockaddr_resolve(&addrs, host, PARSE_PORT_FORBID, AST_AF_UNSPEC) <= 0) {
/* The provided host was actually invalid so we error out this negotiation */
ast_debug(3, "Not applying negotiated SDP stream: failed to resolve remote stream host\n");
return -1;
}
ast_sockaddr_set_port(addrs, remote_stream->desc.port);
ast_udptl_set_peer(session_media->udptl, addrs);
t38_interpret_sdp(state, session, session_media, remote_stream);
ast_sip_session_media_set_write_callback(session, session_media, media_session_udptl_write_callback);
ast_sip_session_media_add_read_callback(session, session_media, ast_udptl_fd(session_media->udptl),
media_session_udptl_read_callback);
return 0;
}
/*! \brief Function which updates the media stream with external media address, if applicable */
static void change_outgoing_sdp_stream_media_address(pjsip_tx_data *tdata, struct pjmedia_sdp_media *stream, struct ast_sip_transport *transport)
{
RAII_VAR(struct ast_sip_transport_state *, transport_state, ast_sip_get_transport_state(ast_sorcery_object_get_id(transport)), ao2_cleanup);
char host[NI_MAXHOST];
struct ast_sockaddr our_sdp_addr = { { 0, } };
/* If the stream has been rejected there will be no connection line */
if (!stream->conn || !transport_state) {
return;
}
ast_copy_pj_str(host, &stream->conn->addr, sizeof(host));
ast_sockaddr_parse(&our_sdp_addr, host, PARSE_PORT_FORBID);
/* Reversed check here. We don't check the remote endpoint being
* in our local net, but whether our outgoing session IP is
* local. If it is not, we won't do rewriting. No localnet
* configured? Always rewrite. */
if (ast_sip_transport_is_nonlocal(transport_state, &our_sdp_addr) && transport_state->localnet) {
return;
}
ast_debug(5, "Setting media address to %s\n", ast_sockaddr_stringify_host(&transport_state->external_media_address));
pj_strdup2(tdata->pool, &stream->conn->addr, ast_sockaddr_stringify_host(&transport_state->external_media_address));
}
/*! \brief Function which destroys the UDPTL instance when session ends */
static void stream_destroy(struct ast_sip_session_media *session_media)
{
if (session_media->udptl) {
ast_udptl_destroy(session_media->udptl);
}
session_media->udptl = NULL;
}
/*! \brief SDP handler for 'image' media stream */
static struct ast_sip_session_sdp_handler image_sdp_handler = {
.id = "image",
.defer_incoming_sdp_stream = defer_incoming_sdp_stream,
.negotiate_incoming_sdp_stream = negotiate_incoming_sdp_stream,
.create_outgoing_sdp_stream = create_outgoing_sdp_stream,
.apply_negotiated_sdp_stream = apply_negotiated_sdp_stream,
.change_outgoing_sdp_stream_media_address = change_outgoing_sdp_stream_media_address,
.stream_destroy = stream_destroy,
};
/*! \brief Unloads the SIP T.38 module from Asterisk */
static int unload_module(void)
{
ast_sip_session_unregister_sdp_handler(&image_sdp_handler, "image");
ast_sip_session_unregister_supplement(&t38_supplement);
return 0;
}
/*!
* \brief Load the module
*
* Module loading including tests for configuration or dependencies.
* This function can return AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_DECLINE,
* or AST_MODULE_LOAD_SUCCESS. If a dependency or environment variable fails
* tests return AST_MODULE_LOAD_FAILURE. If the module can not load the
* configuration file or other non-critical problem return
* AST_MODULE_LOAD_DECLINE. On success return AST_MODULE_LOAD_SUCCESS.
*/
static int load_module(void)
{
if (ast_check_ipv6()) {
ast_sockaddr_parse(&address, "::", 0);
} else {
ast_sockaddr_parse(&address, "0.0.0.0", 0);
}
ast_sip_session_register_supplement(&t38_supplement);
if (ast_sip_session_register_sdp_handler(&image_sdp_handler, "image")) {
ast_log(LOG_ERROR, "Unable to register SDP handler for image stream type\n");
goto end;
}
return AST_MODULE_LOAD_SUCCESS;
end:
unload_module();
return AST_MODULE_LOAD_DECLINE;
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP T.38 UDPTL Support",
.support_level = AST_MODULE_SUPPORT_CORE,
.load = load_module,
.unload = unload_module,
.load_pri = AST_MODPRI_CHANNEL_DRIVER,
.requires = "res_pjsip,res_pjsip_session,udptl",
);