Stasis: Convey transfer information to applications

This fixes a class of issues where Stasis applications were not made
aware that their channels were being manipulated or replaced by
external entitiessuch as transfers, AMI commands, or dialplan
applications such as Bridge(). Inconsistent information such as
StasisEnd events with unknown channels as a result of masquerades has
also been corrected. To accomplish these fixes, several new fields
were added to blind and attended transfer messages as well as
StasisStart and BridgeAttendedTransfer Stasis events.

ASTERISK-23941 #close
Review: https://reviewboard.asterisk.org/r/3865/
Review: https://reviewboard.asterisk.org/r/3857/
Review: https://reviewboard.asterisk.org/r/3852/
Review: https://reviewboard.asterisk.org/r/3816/
Review: https://reviewboard.asterisk.org/r/3731/
Review: https://reviewboard.asterisk.org/r/3729/
Review: https://reviewboard.asterisk.org/r/3728/
........

Merged revisions 420325 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@420338 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 116 insertions, 8 deletions

diff --git a/main/bridge_basic.c b/main/bridge_basic.c
index 0d95d83d2..a69750d15 100644
--- a/main/bridge_basic.c
+++ b/main/bridge_basic.c
@@ -1526,9 +1526,85 @@ static void stimulate_attended_transfer(struct attended_transfer_properties *pro
 }
 
 /*!
+ * \brief Get a desired transfer party for a bridge the transferer is not in.
+ *
+ * \param bridge The bridge to get the party from. May be NULL.
+ * \param[out] party The lone channel in the bridge. Will be set NULL if bridge is NULL or multiple parties are present.
+ */
+static void get_transfer_party_non_transferer_bridge(struct ast_bridge *bridge,
+		struct ast_channel **party)
+{
+	if (bridge && bridge->num_channels == 1) {
+		*party = ast_channel_ref(AST_LIST_FIRST(&bridge->channels)->chan);
+	} else {
+		*party = NULL;
+	}
+}
+
+/*!
+ * \brief Get the transferee and transfer target when the transferer is in a bridge with
+ * one of the desired parties.
+ *
+ * \param transferer_bridge The bridge the transferer is in
+ * \param other_bridge The bridge the transferer is not in. May be NULL.
+ * \param transferer The transferer party
+ * \param[out] transferer_peer The party that is in the bridge with the transferer
+ * \param[out] other_party The party that is in the other_bridge
+ */
+static void get_transfer_parties_transferer_bridge(struct ast_bridge *transferer_bridge,
+		struct ast_bridge *other_bridge, struct ast_channel *transferer,
+		struct ast_channel **transferer_peer, struct ast_channel **other_party)
+{
+	*transferer_peer = ast_bridge_peer(transferer_bridge, transferer);
+	get_transfer_party_non_transferer_bridge(other_bridge, other_party);
+}
+
+/*!
+ * \brief determine transferee and transfer target for an attended transfer
+ *
+ * In builtin attended transfers, there is a single transferer channel that jumps between
+ * the two bridges involved. At the time the attended transfer occurs, the transferer could
+ * be in either bridge, so determining the parties is a bit more complex than normal.
+ *
+ * The method used here is to determine which of the two bridges the transferer is in, and
+ * grabbing the peer from that bridge. The other bridge, if it only has a single channel in it,
+ * has the other desired channel.
+ *
+ * \param transferer The channel performing the transfer
+ * \param transferee_bridge The bridge that the transferee is in
+ * \param target_bridge The bridge that the transfer target is in
+ * \param[out] transferee The transferee channel
+ * \param[out] transfer_target The transfer target channel
+ */
+static void get_transfer_parties(struct ast_channel *transferer, struct ast_bridge *transferee_bridge,
+		struct ast_bridge *target_bridge, struct ast_channel **transferee,
+		struct ast_channel **transfer_target)
+{
+	struct ast_bridge *transferer_bridge;
+
+	ast_channel_lock(transferer);
+	transferer_bridge = ast_channel_get_bridge(transferer);
+	ast_channel_unlock(transferer);
+
+	if (transferer_bridge == transferee_bridge) {
+		get_transfer_parties_transferer_bridge(transferee_bridge, target_bridge,
+				transferer, transferee, transfer_target);
+	} else if (transferer_bridge == target_bridge) {
+		get_transfer_parties_transferer_bridge(target_bridge, transferee_bridge,
+				transferer, transfer_target, transferee);
+	} else {
+		get_transfer_party_non_transferer_bridge(transferee_bridge, transferee);
+		get_transfer_party_non_transferer_bridge(target_bridge, transfer_target);
+	}
+
+	ao2_cleanup(transferer_bridge);
+}
+
+/*!
  * \brief Send a stasis publication for a successful attended transfer
  */
-static void publish_transfer_success(struct attended_transfer_properties *props)
+static void publish_transfer_success(struct attended_transfer_properties *props,
+		struct ast_channel *transferee_channel, struct ast_channel *target_channel)
 {
 	struct ast_bridge_channel_pair transferee = {
 		.channel = props->transferer,
@@ -1548,7 +1624,8 @@ static void publish_transfer_success(struct attended_transfer_properties *props)
 	}
 
 	ast_bridge_publish_attended_transfer_bridge_merge(0, AST_BRIDGE_TRANSFER_SUCCESS,
-			&transferee, &transfer_target, props->transferee_bridge);
+			&transferee, &transfer_target, props->transferee_bridge, transferee_channel,
+			target_channel);
 
 	if (transferee.bridge) {
 		ast_bridge_unlock(transferee.bridge);
@@ -1561,7 +1638,8 @@ static void publish_transfer_success(struct attended_transfer_properties *props)
 /*!
  * \brief Send a stasis publication for an attended transfer that ends in a threeway call
  */
-static void publish_transfer_threeway(struct attended_transfer_properties *props)
+static void publish_transfer_threeway(struct attended_transfer_properties *props,
+		struct ast_channel *transferee_channel, struct ast_channel *target_channel)
 {
 	struct ast_bridge_channel_pair transferee = {
 		.channel = props->transferer,
@@ -1585,7 +1663,8 @@ static void publish_transfer_threeway(struct attended_transfer_properties *props
 	}
 
 	ast_bridge_publish_attended_transfer_threeway(0, AST_BRIDGE_TRANSFER_SUCCESS,
-			&transferee, &transfer_target, &threeway);
+			&transferee, &transfer_target, &threeway, transferee_channel,
+			target_channel);
 
 	if (transferee.bridge) {
 		ast_bridge_unlock(transferee.bridge);
@@ -1608,6 +1687,8 @@ static void publish_transfer_fail(struct attended_transfer_properties *props)
 		.channel = props->transferer,
 		.bridge = props->target_bridge,
 	};
+	struct ast_channel *transferee_channel;
+	struct ast_channel *target_channel;
 
 	if (transferee.bridge && transfer_target.bridge) {
 		ast_bridge_lock_both(transferee.bridge, transfer_target.bridge);
@@ -1617,8 +1698,12 @@ static void publish_transfer_fail(struct attended_transfer_properties *props)
 		ast_bridge_lock(transfer_target.bridge);
 	}
 
+	get_transfer_parties(props->transferer, props->transferee_bridge, props->target_bridge,
+			&transferee_channel, &target_channel);
 	ast_bridge_publish_attended_transfer_fail(0, AST_BRIDGE_TRANSFER_FAIL,
-			&transferee, &transfer_target);
+			&transferee, &transfer_target, transferee_channel, target_channel);
+	ast_channel_cleanup(transferee_channel);
+	ast_channel_cleanup(target_channel);
 
 	if (transferee.bridge) {
 		ast_bridge_unlock(transferee.bridge);
@@ -2072,11 +2157,18 @@ static int resume_enter(struct attended_transfer_properties *props)
 
 static int threeway_enter(struct attended_transfer_properties *props)
 {
+	struct ast_channel *transferee_channel;
+	struct ast_channel *target_channel;
+
+	get_transfer_parties(props->transferer, props->transferee_bridge, props->target_bridge,
+			&transferee_channel, &target_channel);
 	bridge_merge(props->transferee_bridge, props->target_bridge, NULL, 0);
 	play_sound(props->transfer_target, props->xfersound);
 	play_sound(props->transferer, props->xfersound);
-	publish_transfer_threeway(props);
+	publish_transfer_threeway(props, transferee_channel, target_channel);
 
+	ast_channel_cleanup(transferee_channel);
+	ast_channel_cleanup(target_channel);
 	return 0;
 }
 
@@ -2178,17 +2270,33 @@ static enum attended_transfer_state double_checking_exit(struct attended_transfe
 
 static int complete_enter(struct attended_transfer_properties *props)
 {
+	struct ast_channel *transferee_channel;
+	struct ast_channel *target_channel;
+
+	get_transfer_parties(props->transferer, props->transferee_bridge, props->target_bridge,
+			&transferee_channel, &target_channel);
 	bridge_merge(props->transferee_bridge, props->target_bridge, &props->transferer, 1);
 	play_sound(props->transfer_target, props->xfersound);
-	publish_transfer_success(props);
+	publish_transfer_success(props, transferee_channel, target_channel);
+
+	ast_channel_cleanup(transferee_channel);
+	ast_channel_cleanup(target_channel);
 	return 0;
 }
 
 static int blond_enter(struct attended_transfer_properties *props)
 {
+	struct ast_channel *transferee_channel;
+	struct ast_channel *target_channel;
+
+	get_transfer_parties(props->transferer, props->transferee_bridge, props->target_bridge,
+			&transferee_channel, &target_channel);
 	bridge_merge(props->transferee_bridge, props->target_bridge, &props->transferer, 1);
 	ringing(props->transfer_target);
-	publish_transfer_success(props);
+	publish_transfer_success(props, transferee_channel, target_channel);
+
+	ast_channel_cleanup(transferee_channel);
+	ast_channel_cleanup(target_channel);
 	return 0;
 }