Asterisk
/
asterisk
mirror of https://github.com/asterisk/asterisk
1
0
Fork 0
Code Issues Releases Wiki Activity

SDP: Rework merge_capabilities().

Browse Source 
* Tried to give better variable names.
* Made our SDP answer use the offer's RTP payload types as the SDP RFC
says we SHOULD.
* Updating the local topology now takes the stream format caps.  We are
likely preparing to send an offer.

Change-Id: I34d3be8e3036402a8575ffcae3eebc5ce348d7c0
pull/7/head
Richard Mudgett 8 years ago
parent ae7689f093
commit be5809fac8
1 changed files with 120 additions and 56 deletions
Show Stats Download Patch File Download Diff File

176
main/sdp_state.c
Unescape View File

@ -522,6 +522,7 @@ const struct ast_sdp_options *ast_sdp_state_get_options(
*
* \param local Our local stream
* \param remote A remote stream
*
* \retval NULL An error occurred
* \retval non-NULL The joint stream created
*/
@ -542,10 +543,6 @@ static struct ast_stream *merge_streams(const struct ast_stream *local,
return NULL;
}
if (!local) {
return joint_stream;
}
joint_cap = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
if (!joint_cap) {
ast_stream_free(joint_stream);
@ -576,63 +573,100 @@ static struct ast_stream *merge_streams(const struct ast_stream *local,
* \param local The local topology
* \param media_type The type of stream we are looking for
* \param[in,out] media_indices Keeps track of where to start searching in the topology
* \retval NULL No corresponding stream found
* \retval non-NULL The corresponding stream
*
* \retval -1 No corresponding stream found
* \retval index The corresponding stream index
*/
static int get_corresponding_index(const struct ast_stream_topology *local,
enum ast_media_type media_type, int *media_indices)
{
int i;
int winner = -1;
for (i = media_indices[media_type]; i < ast_stream_topology_get_count(local); ++i) {
struct ast_stream *candidate;
candidate = ast_stream_topology_get_stream(local, i);
if (ast_stream_get_type(candidate) == media_type) {
winner = i;
break;
media_indices[media_type] = i + 1;
return i;
}
}
media_indices[media_type] = i + 1;
return winner;
/* No stream of the type left in the topology */
media_indices[media_type] = i;
return -1;
}
/*!
* XXX TODO The merge_capabilities() function needs to be split into
* merging for new local topologies and new remote topologies. Also
* the possibility of changing the stream types needs consideration.
* Audio to video may or may not need us to keep the same RTP instance
* because the stream position is still RTP. A new RTP instance would
* cause us to change ports. Audio to image is definitely going to
* happen for T.38.
*
* A new remote topology as an initial offer needs to dictate the
* number of streams and the order. As a sdp_state option we may
* allow creation of new active streams not defined by the current
* local topology. A subsequent remote offer can change the stream
* types and add streams. The sdp_state option could regulate
* creation of new active streams here as well. An answer cannot
* change stream types or the number of streams but can decline
* streams. Any attempt to do so should report an error and possibly
* disconnect the call.
*
* A local topology update needs to be merged differently. It cannot
* reduce the number of streams already defined without violating the
* SDP RFC. The local merge could take the new topology stream
* verbatim and add declined streams to fill out any shortfall with
* the exiting topology. This strategy is needed if we want to change
* an audio stream to an image stream for T.38 fax and vice versa.
* The local merge could take the new topology and map the streams to
* the existing local topology. The new topology stream format caps
* would be copied into the merged topology so we could change what
* codecs are negotiated.
*/
/*!
* \brief Merge existing stream capabilities and a new topology into joint capabilities.
*
* This is a bit complicated. The idea is that we already have some capabilities set, and
* we've now been confronted with a new stream topology. We want to take what's been
* presented to us and merge those new capabilities with our own.
* \param sdp_state The state needing capabilities merged
* \param new_topology The new topology to base merged capabilities on
* \param is_local If new_topology is a local update.
*
* For each of the new streams, we try to find a corresponding stream in our current
* capabilities. If we find one, then we get the compatible formats of the two streams
* and create a new stream with those formats set. We then will re-use the underlying
* media instance (such as an RTP instance) on this merged stream.
* \details
* This is a bit complicated. The idea is that we already have some
* capabilities set, and we've now been confronted with a new stream
* topology. We want to take what's been presented to us and merge
* those new capabilities with our own.
*
* The create_new parameter determines whether we should attempt to create new media
* instances.
* If we do not find a corresponding stream, then we create a new one. If the
* create_new parameter is true, this created stream is made a clone of the new stream,
* and a media instance is created. If the create_new parameter is not true, then the
* created stream has no formats set and no media instance is created for it.
* For each of the new streams, we try to find a corresponding stream
* in our proposed capabilities. If we find one, then we get the
* compatible formats of the two streams and create a new stream with
* those formats set. We then will re-use the underlying media
* instance (such as an RTP instance) on this merged stream.
*
* The is_local parameter determines whether we should attempt to
* create new media instances. If we do not find a corresponding
* stream, then we create a new one. If the is_local parameter is
* true, this created stream is made a clone of the new stream, and a
* media instance is created. If the is_local parameter is not true,
* then the created stream has no formats set and no media instance is
* created for it.
*
* \param current Current capabilities of the SDP state (may be NULL)
* \param new_topology The new topology to base merged capabilities on
* \param options The options set on the SDP state
* \retval NULL An error occurred
* \retval non-NULL The merged capabilities
*/
static struct sdp_state_capabilities *merge_capabilities(const struct sdp_state_capabilities *current,
const struct ast_stream_topology *new_topology, const struct ast_sdp_options *options, int create_missing)
static struct sdp_state_capabilities *merge_capabilities(const struct ast_sdp_state *sdp_state,
const struct ast_stream_topology *new_topology, int is_local)
{
const struct sdp_state_capabilities *local = sdp_state->proposed_capabilities;
struct sdp_state_capabilities *joint_capabilities;
struct ast_stream_topology *topology;
int media_indices[AST_MEDIA_TYPE_END] = {0};
int i;
static const char dummy_name[] = "dummy";
ast_assert(current != NULL);
ast_assert(local != NULL);
joint_capabilities = ast_calloc(1, sizeof(*joint_capabilities));
if (!joint_capabilities) {
@ -644,20 +678,18 @@ static struct sdp_state_capabilities *merge_capabilities(const struct sdp_state_
goto fail;
}
if (AST_VECTOR_INIT(&joint_capabilities->streams, AST_VECTOR_SIZE(&current->streams))) {
if (AST_VECTOR_INIT(&joint_capabilities->streams, AST_VECTOR_SIZE(&local->streams))) {
goto fail;
}
ast_sockaddr_copy(&joint_capabilities->connection_address, &current->connection_address);
topology = current->topology;
ast_sockaddr_copy(&joint_capabilities->connection_address, &local->connection_address);
for (i = 0; i < ast_stream_topology_get_count(new_topology); ++i) {
enum ast_media_type new_stream_type;
struct ast_stream *new_stream;
struct ast_stream *current_stream;
struct ast_stream *local_stream;
struct ast_stream *joint_stream;
struct sdp_state_stream *current_state_stream;
struct sdp_state_stream *joint_state_stream;
int current_index;
int local_index;
joint_state_stream = ast_calloc(1, sizeof(*joint_state_stream));
if (!joint_state_stream) {
@ -667,26 +699,57 @@ static struct sdp_state_capabilities *merge_capabilities(const struct sdp_state_
new_stream = ast_stream_topology_get_stream(new_topology, i);
new_stream_type = ast_stream_get_type(new_stream);
current_index = get_corresponding_index(topology, new_stream_type, media_indices);
if (current_index >= 0) {
current_stream = ast_stream_topology_get_stream(topology, current_index);
joint_stream = merge_streams(current_stream, new_stream);
local_index = get_corresponding_index(local->topology, new_stream_type, media_indices);
if (0 <= local_index) {
local_stream = ast_stream_topology_get_stream(local->topology, local_index);
if (!strcmp(ast_stream_get_name(local_stream), dummy_name)) {
/* The local stream is a non-exixtent dummy stream. */
local_stream = NULL;
}
} else {
local_stream = NULL;
}
if (local_stream) {
struct sdp_state_stream *local_state_stream;
struct ast_rtp_codecs *codecs;
if (is_local) {
/* Replace the local stream with the new local stream. */
joint_stream = ast_stream_clone(new_stream);
} else {
joint_stream = merge_streams(local_stream, new_stream);
}
if (!joint_stream) {
sdp_state_stream_free(joint_state_stream);
goto fail;
}
current_state_stream = AST_VECTOR_GET(&current->streams, current_index);
joint_state_stream->type = current_state_stream->type;
local_state_stream = AST_VECTOR_GET(&local->streams, local_index);
joint_state_stream->type = local_state_stream->type;
switch (joint_state_stream->type) {
case AST_MEDIA_TYPE_AUDIO:
case AST_MEDIA_TYPE_VIDEO:
joint_state_stream->instance = ao2_bump(current_state_stream->instance);
joint_state_stream->instance = ao2_bump(local_state_stream->instance);
if (is_local) {
break;
}
codecs = ast_stream_get_data(new_stream, AST_STREAM_DATA_RTP_CODECS);
ast_assert(codecs != NULL);
if (sdp_state->role == SDP_ROLE_ANSWERER) {
/*
* Setup rx payload type mapping to prefer the mapping
* from the peer that the RFC says we SHOULD use.
*/
ast_rtp_codecs_payloads_xover(codecs, codecs, NULL);
}
ast_rtp_codecs_payloads_copy(codecs,
ast_rtp_instance_get_codecs(joint_state_stream->instance),
joint_state_stream->instance);
break;
case AST_MEDIA_TYPE_IMAGE:
joint_state_stream->udptl = ao2_bump(current_state_stream->udptl);
joint_state_stream->t38_local_params = current_state_stream->t38_local_params;
joint_state_stream->udptl = ao2_bump(local_state_stream->udptl);
joint_state_stream->t38_local_params = local_state_stream->t38_local_params;
break;
case AST_MEDIA_TYPE_UNKNOWN:
case AST_MEDIA_TYPE_TEXT:
@ -694,13 +757,14 @@ static struct sdp_state_capabilities *merge_capabilities(const struct sdp_state_
break;
}
if (!ast_sockaddr_isnull(&current_state_stream->connection_address)) {
ast_sockaddr_copy(&joint_state_stream->connection_address, &current_state_stream->connection_address);
if (!ast_sockaddr_isnull(&local_state_stream->connection_address)) {
ast_sockaddr_copy(&joint_state_stream->connection_address,
&local_state_stream->connection_address);
} else {
ast_sockaddr_setnull(&joint_state_stream->connection_address);
}
joint_state_stream->locally_held = current_state_stream->locally_held;
} else if (create_missing) {
joint_state_stream->locally_held = local_state_stream->locally_held;
} else if (is_local) {
/* We don't have a stream state that corresponds to the stream in the new topology, so
* create a stream state as appropriate.
*/
@ -713,7 +777,8 @@ static struct sdp_state_capabilities *merge_capabilities(const struct sdp_state_
switch (new_stream_type) {
case AST_MEDIA_TYPE_AUDIO:
case AST_MEDIA_TYPE_VIDEO:
joint_state_stream->instance = create_rtp(options, new_stream_type);
joint_state_stream->instance = create_rtp(sdp_state->options,
new_stream_type);
if (!joint_state_stream->instance) {
ast_stream_free(joint_stream);
sdp_state_stream_free(joint_state_stream);
@ -721,7 +786,7 @@ static struct sdp_state_capabilities *merge_capabilities(const struct sdp_state_
}
break;
case AST_MEDIA_TYPE_IMAGE:
joint_state_stream->udptl = create_udptl(options);
joint_state_stream->udptl = create_udptl(sdp_state->options);
if (!joint_state_stream->udptl) {
ast_stream_free(joint_stream);
sdp_state_stream_free(joint_state_stream);
@ -740,7 +805,7 @@ static struct sdp_state_capabilities *merge_capabilities(const struct sdp_state_
* dummy stream to go in its place so that the resulting SDP created will contain
* the stream but will have no port or codecs set
*/
joint_stream = ast_stream_alloc("dummy", new_stream_type);
joint_stream = ast_stream_alloc(dummy_name, new_stream_type);
if (!joint_stream) {
sdp_state_stream_free(joint_state_stream);
goto fail;
@ -1013,8 +1078,7 @@ static int merge_sdps(struct ast_sdp_state *sdp_state, const struct ast_sdp *rem
return -1;
}
joint_capabilities = merge_capabilities(sdp_state->proposed_capabilities,
remote_capabilities, sdp_state->options, 0);
joint_capabilities = merge_capabilities(sdp_state, remote_capabilities, 0);
ast_stream_topology_free(remote_capabilities);
if (!joint_capabilities) {
return -1;
@ -1127,7 +1191,7 @@ int ast_sdp_state_update_local_topology(struct ast_sdp_state *sdp_state, struct
ast_assert(sdp_state != NULL);
ast_assert(streams != NULL);
capabilities = merge_capabilities(sdp_state->proposed_capabilities, streams, sdp_state->options, 1);
capabilities = merge_capabilities(sdp_state, streams, 1);
if (!capabilities) {
return -1;
}

Write Preview
Loading…
Cancel
Save