Better handle parking in CDRs

Parking typically occurs when a channel is transferred to a parking extension.
When this occurs, the channel never actually hits the dialplan if the extension
it was transferred to was a "parking extension", that is, the extension in
the first priority calls the Park application. Instead, the channel is
immediately sent into the holding bridge acting as the parking bridge.

This is problematic.

Because we never go out to the dialplan, the CDRs won't transition properly
and the application field will not be set to "Park". CDRs typically swallow
holding bridges, so the CDR itself won't even be generated.

This patch handles this by pulling out the holding bridge handling into its
own CDR state. CDRs now have an explicit parking state that accounts for this
specific subclass of the holding bridge. In addition, we handle the parking
stasis message to set application specific data on the CDR such that the
last known application for the CDR properly reflects "Park".

This is a bit sad since we're working around the odd internal implementation
of parking that exists in Asterisk (and that we had to maintain in order to
continue to meet some odd use cases of parking), but at least the code to
handle that is where it belongs: in CDRs as opposed to sprinkled liberally
throughout the codebase.

This patch also properly clears the OUTBOUND channel flag from a channel when
it leaves a bridge, and tweaks up dialing handling to properly compare the
correct CDR with the channel calling/being dialed.




git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@393130 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/cdr.h

@@ -99,6 +99,9 @@
  * has hung up, the state transitions to Finalized
  * \li If a \ref ast_bridge_blob_type is received indicating a Bridge Enter, the
  * state transitions to Bridge
+ * \li If a \ref ast_bridge_blob_type message indicating an entrance to a
+ * holding bridge with a subclass type of "parking" is received, the CDR is
+ * transitioned to the Parked state.
  *
  * \par Dial
  *
@@ -138,6 +141,9 @@
  * if we have a Party B. Otherwise, we transition to the Single state.
  * \li If a \ref ast_bridge_blob_type is received indicating a Bridge Enter, the
  * state transitions to Bridge (through the Dial state)
+ * \li If a \ref ast_bridge_blob_type message indicating an entrance to a
+ * holding bridge with a subclass type of "parking" is received, the CDR is
+ * transitioned to the Parked state.
  *
  * \par Bridge
  *
@@ -174,6 +180,31 @@
  * \li If a \ref ast_bridge_blob_type message indicating a leave is received,
  * the state transitions to the Pending state
  *
+ * \par Parked
+ *
+ * Parking is technically just another bridge in the Asterisk bridging
+ * framework. Unlike other bridges, however there are several key distinctions:
+ * \li With normal bridges, you want to show paths of communication between
+ * the participants. In parking, however, each participant is independent.
+ * From the perspective of a CDR, a call in parking should look like a dialplan
+ * application just executed.
+ * \li Holding bridges are typically items using in more complex applications,
+ * and so we usually don't want to show them. However, with Park, there is no
+ * application execution - often, a channel will be put directly into the
+ * holding bridge, bypassing the dialplan. This occurs when a call is blind
+ * transferred to a parking extension.
+ *
+ * As such, if a channel enters a bridge and that happens to be a holding bridge
+ * with a subclass type of "parking", we transition the CDR into the Parked
+ * state. The parking Stasis message updates the application name and data to
+ * reflect that the channel is in parking. When this occurs, a special flag is
+ * set on the CDR that prevents the application name from being updates by
+ * subsequent channel snapshot updates.
+ *
+ * The following transitions can occur while in the Parked state:
+ * \li If a \ref ast_bridge_blob_type message indicating a leave is received,
+ * the state transitions to the Pending state
+ *
  * \par Pending
  *
  * After a channel leaves a bridge, we often don't know what's going to happen
@@ -190,6 +221,9 @@
  * Context/Extension/Priority, a new CDR is created and transitioned to the
  * Single state. If the update indicates that the party has been hung up, the
  * CDR is transitioned to the Finalized state.
+ * \li If a \ref ast_bridge_blob_type message indicating an entrance to a
+ * holding bridge with a subclass type of "parking" is received, the CDR is
+ * transitioned to the Parked state.
  *
  * \par Finalized
  *
@@ -203,19 +237,19 @@
 
 /*! \brief CDR engine settings */
 enum ast_cdr_settings {
-	CDR_ENABLED = 1 << 0,				/*< Enable CDRs */
-	CDR_BATCHMODE = 1 << 1,				/*< Whether or not we should dispatch CDRs in batches */
-	CDR_UNANSWERED = 1 << 2,			/*< Log unanswered CDRs */
-	CDR_CONGESTION = 1 << 3,			/*< Treat congestion as if it were a failed call */
-	CDR_END_BEFORE_H_EXTEN = 1 << 4,	/*< End the CDR before the 'h' extension runs */
-	CDR_INITIATED_SECONDS = 1 << 5,		/*< Include microseconds into the billing time */
-	CDR_DEBUG = 1 << 6,					/*< Enables extra debug statements */
+	CDR_ENABLED = 1 << 0,               /*< Enable CDRs */
+	CDR_BATCHMODE = 1 << 1,             /*< Whether or not we should dispatch CDRs in batches */
+	CDR_UNANSWERED = 1 << 2,            /*< Log unanswered CDRs */
+	CDR_CONGESTION = 1 << 3,            /*< Treat congestion as if it were a failed call */
+	CDR_END_BEFORE_H_EXTEN = 1 << 4,    /*< End the CDR before the 'h' extension runs */
+	CDR_INITIATED_SECONDS = 1 << 5,     /*< Include microseconds into the billing time */
+	CDR_DEBUG = 1 << 6,                 /*< Enables extra debug statements */
 };
 
 /*! \brief CDR Batch Mode settings */
 enum ast_cdr_batch_mode_settings {
-	BATCH_MODE_SCHEDULER_ONLY = 1 << 0,	/*< Don't spawn a thread to handle the batches - do it on the scheduler */
-	BATCH_MODE_SAFE_SHUTDOWN = 1 << 1,	/*< During safe shutdown, submit the batched CDRs */
+	BATCH_MODE_SCHEDULER_ONLY = 1 << 0, /*< Don't spawn a thread to handle the batches - do it on the scheduler */
+	BATCH_MODE_SAFE_SHUTDOWN = 1 << 1,  /*< During safe shutdown, submit the batched CDRs */
 };
 
 /*!
@@ -223,24 +257,25 @@ enum ast_cdr_batch_mode_settings {
  * state of a CDR object based on these flags.
  */
 enum ast_cdr_options {
-	AST_CDR_FLAG_KEEP_VARS = (1 << 0),			/*< Copy variables during the operation */
-	AST_CDR_FLAG_DISABLE = (1 << 1),			/*< Disable the current CDR */
-	AST_CDR_FLAG_DISABLE_ALL = (3 << 1),		/*< Disable the CDR and all future CDRs */
-	AST_CDR_FLAG_PARTY_A = (1 << 3),			/*< Set the channel as party A */
-	AST_CDR_FLAG_FINALIZE = (1 << 4),			/*< Finalize the current CDRs */
-	AST_CDR_FLAG_SET_ANSWER = (1 << 5),			/*< If the channel is answered, set the answer time to now */
-	AST_CDR_FLAG_RESET = (1 << 6),				/*< If set, set the start and answer time to now */
+	AST_CDR_FLAG_KEEP_VARS = (1 << 0),   /*< Copy variables during the operation */
+	AST_CDR_FLAG_DISABLE = (1 << 1),     /*< Disable the current CDR */
+	AST_CDR_FLAG_DISABLE_ALL = (3 << 1), /*< Disable the CDR and all future CDRs */
+	AST_CDR_FLAG_PARTY_A = (1 << 3),     /*< Set the channel as party A */
+	AST_CDR_FLAG_FINALIZE = (1 << 4),    /*< Finalize the current CDRs */
+	AST_CDR_FLAG_SET_ANSWER = (1 << 5),  /*< If the channel is answered, set the answer time to now */
+	AST_CDR_FLAG_RESET = (1 << 6),       /*< If set, set the start and answer time to now */
+	AST_CDR_LOCK_APP = (1 << 7),         /*< Prevent any further changes to the application field/data field for this CDR */
 };
 
 /*!
  * \brief CDR Flags - Disposition
  */
 enum ast_cdr_disposition {
-	AST_CDR_NOANSWER = 0,
-	AST_CDR_NULL     = (1 << 0),
-	AST_CDR_FAILED   = (1 << 1),
-	AST_CDR_BUSY     = (1 << 2),
-	AST_CDR_ANSWERED = (1 << 3),
+	AST_CDR_NOANSWER   = 0,
+	AST_CDR_NULL       = (1 << 0),
+	AST_CDR_FAILED     = (1 << 1),
+	AST_CDR_BUSY       = (1 << 2),
+	AST_CDR_ANSWERED   = (1 << 3),
 	AST_CDR_CONGESTION = (1 << 4),
 };