Added loop transport to test transaction

git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@107 74dad513-b988-da41-8d7b-12977e46ad98

10 files changed, 343 insertions, 123 deletions

diff --git a/pjsip/include/pjsip/sip_config.h b/pjsip/include/pjsip/sip_config.h
index 592aea41..158d4a75 100644
--- a/pjsip/include/pjsip/sip_config.h
+++ b/pjsip/include/pjsip/sip_config.h
@@ -45,6 +45,14 @@
 #define PJSIP_RFC3261_BRANCH_ID		"z9hG4bK"
 #define PJSIP_RFC3261_BRANCH_LEN	7
 
+/* Transaction related constants. */
+#define PJSIP_POOL_TSX_LAYER_LEN	4000
+#define PJSIP_POOL_TSX_LAYER_INC	4000
+#define PJSIP_MAX_TSX_COUNT		(16*1024)
+#define PJSIP_POOL_TSX_LEN		1536 //768
+#define PJSIP_POOL_TSX_INC		256
+#define PJSIP_MAX_TSX_KEY_LEN		(PJSIP_MAX_URL_SIZE*2)
+
 /* Message/URL related constants. */
 #define PJSIP_MAX_CALL_ID_LEN		PJ_GUID_STRING_LENGTH
 #define PJSIP_MAX_TAG_LEN		PJ_GUID_STRING_LENGTH
@@ -52,12 +60,6 @@
 #define PJSIP_MAX_URL_SIZE		256
 #define PJSIP_MAX_HNAME_LEN		64
 
-/* Transction related constants. */
-#define PJSIP_MAX_TSX_COUNT		(16*1024)
-#define PJSIP_POOL_LEN_TSX		1536 //768
-#define PJSIP_POOL_INC_TSX		256
-#define PJSIP_MAX_TSX_KEY_LEN		(PJSIP_MAX_URL_SIZE*2)
-
 /* Dialog related constants. */
 #define PJSIP_MAX_DIALOG_COUNT		(16*1024)
 #define PJSIP_POOL_LEN_DIALOG		1200
diff --git a/pjsip/include/pjsip/sip_endpoint.h b/pjsip/include/pjsip/sip_endpoint.h
index d9d03a97..527cd886 100644
--- a/pjsip/include/pjsip/sip_endpoint.h
+++ b/pjsip/include/pjsip/sip_endpoint.h
@@ -209,7 +209,7 @@ PJ_DECL(pj_pool_t*) pjsip_endpt_create_pool( pjsip_endpoint *endpt,
  * @param endpt	    The endpoint.
  * @param pool	    The pool to be destroyed.
  */
-PJ_DECL(void) pjsip_endpt_destroy_pool( pjsip_endpoint *endpt,
+PJ_DECL(void) pjsip_endpt_release_pool( pjsip_endpoint *endpt,
 					pj_pool_t *pool );
 
 /**
diff --git a/pjsip/include/pjsip/sip_errno.h b/pjsip/include/pjsip/sip_errno.h
index 4d50c75d..253e6c00 100644
--- a/pjsip/include/pjsip/sip_errno.h
+++ b/pjsip/include/pjsip/sip_errno.h
@@ -151,6 +151,11 @@ PJ_DECL(pj_str_t) pjsip_strerror( pj_status_t status, char *buffer,
  * Expecting response message.
  */
 #define PJSIP_ENOTRESPONSEMSG	(PJSIP_ERRNO_START_PJSIP + 31)	/* 171031 */
+/**
+ * @hideinitializer
+ * Invalid header field.
+ */
+#define PJSIP_EINVALIDHDR	(PJSIP_ERRNO_START_PJSIP + 32)	/* 171032 */
 
 
 /************************************************************
diff --git a/pjsip/include/pjsip/sip_msg.h b/pjsip/include/pjsip/sip_msg.h
index e1866048..29bd9766 100644
--- a/pjsip/include/pjsip/sip_msg.h
+++ b/pjsip/include/pjsip/sip_msg.h
@@ -499,9 +499,13 @@ typedef struct pjsip_msg_body
      *  For incoming messages, the parser will fill in this member with the
      *  content type found in Content-Type header.
      *
-     *  For outgoing messages, application must fill in this member with
+     *  For outgoing messages, application may fill in this member with
      *  appropriate value, because the stack will generate Content-Type header
      *  based on the value specified here.
+     *
+     *  If the content_type is empty, no Content-Type AND Content-Length header
+     *  will be added to the message. The stack assumes that application adds
+     *  these headers themselves.
      */
     pjsip_media_type content_type;
 
@@ -543,6 +547,19 @@ typedef struct pjsip_msg_body
     int (*print_body)(struct pjsip_msg_body *msg_body, 
 		      char *buf, pj_size_t size);
 
+    /** Clone the data part only of this message body. Note that this only
+     *  duplicates the data part of the body instead of the whole message
+     *  body. If application wants to duplicate the entire message body
+     *  structure, it must call #pjsip_msg_body_clone().
+     *
+     *  @param pool	    Pool used to clone the data.
+     *  @param data	    The data inside message body, to be cloned.
+     *  @param len	    The length of the data.
+     *
+     *  @return		    New data duplicated from the original data.
+     */
+    void* (*clone_data)(pj_pool_t *pool, const void *data, unsigned len);
+
 } pjsip_msg_body;
 
 /**
@@ -562,6 +579,22 @@ PJ_DECL(int) pjsip_print_text_body( pjsip_msg_body *msg_body,
 				    char *buf, pj_size_t size);
 
 /**
+ * Clone the message body in src_body to the dst_body. This will duplicate
+ * the contents of the message body using the \a clone_data member of the
+ * source message body.
+ *
+ * @param pool		Pool to use to duplicate the message body.
+ * @param dst_body	Destination message body.
+ * @param src_body	Source message body to duplicate.
+ *
+ * @return		PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjsip_msg_body_clone(pj_pool_t *pool,
+					  pjsip_msg_body *dst_body,
+					  const pjsip_msg_body *src_body );
+					   
+
+/**
  * @}
  */
 
diff --git a/pjsip/include/pjsip/sip_transaction.h b/pjsip/include/pjsip/sip_transaction.h
index c0627aab..5d2a5126 100644
--- a/pjsip/include/pjsip/sip_transaction.h
+++ b/pjsip/include/pjsip/sip_transaction.h
@@ -25,7 +25,7 @@
  */
 
 #include <pjsip/sip_msg.h>
-#include <pjsip/sip_resolve.h>
+#include <pjsip/sip_util.h>
 #include <pj/timer.h>
 
 PJ_BEGIN_DECL
@@ -36,42 +36,26 @@ PJ_BEGIN_DECL
  * @{
  */
 
-/* Forward decl. */
-struct pjsip_transaction;
-
-
 /**
- * Transaction state.
+ * This enumeration represents transaction state.
  */
 typedef enum pjsip_tsx_state_e
 {
-    PJSIP_TSX_STATE_NULL,
-    PJSIP_TSX_STATE_CALLING,
-    PJSIP_TSX_STATE_TRYING,
-    PJSIP_TSX_STATE_PROCEEDING,
-    PJSIP_TSX_STATE_COMPLETED,
-    PJSIP_TSX_STATE_CONFIRMED,
-    PJSIP_TSX_STATE_TERMINATED,
-    PJSIP_TSX_STATE_DESTROYED,
-    PJSIP_TSX_STATE_MAX,
+    PJSIP_TSX_STATE_NULL,	/**< For UAC, before any message is sent.   */
+    PJSIP_TSX_STATE_CALLING,	/**< For UAC, just after request is sent.   */
+    PJSIP_TSX_STATE_TRYING,	/**< For UAS, just after request is received.*/
+    PJSIP_TSX_STATE_PROCEEDING,	/**< For UAS/UAC, after provisional response.*/
+    PJSIP_TSX_STATE_COMPLETED,	/**< For UAS/UAC, after final response.	    */
+    PJSIP_TSX_STATE_CONFIRMED,	/**< For UAS, after ACK is received.	    */
+    PJSIP_TSX_STATE_TERMINATED,	/**< For UAS/UAC, before it's destroyed.    */
+    PJSIP_TSX_STATE_DESTROYED,	/**< For UAS/UAC, will be destroyed now.    */
+    PJSIP_TSX_STATE_MAX,	/**< Number of states.			    */
 } pjsip_tsx_state_e;
 
 
 /**
- * State of the transport in the transaction.
- * The transport is progressing independently of the transaction.
- */
-typedef enum pjsip_tsx_transport_state_e
-{
-    PJSIP_TSX_TRANSPORT_STATE_NULL,
-    PJSIP_TSX_TRANSPORT_STATE_RESOLVING,
-    PJSIP_TSX_TRANSPORT_STATE_CONNECTING,
-    PJSIP_TSX_TRANSPORT_STATE_FINAL,
-} pjsip_tsx_transport_state_e;
-
-
-/**
- * Transaction state.
+ * This structure describes SIP transaction object. The transaction object
+ * is used to handle both UAS and UAC transaction.
  */
 struct pjsip_transaction
 {
@@ -79,18 +63,18 @@ struct pjsip_transaction
      * Administrivia
      */
     pj_pool_t		       *pool;           /**< Pool owned by the tsx. */
+    pjsip_module	       *tsx_user;	/**< Transaction user.	    */
     pjsip_endpoint	       *endpt;          /**< Endpoint instance.     */
     pj_mutex_t		       *mutex;          /**< Mutex for this tsx.    */
-    char			obj_name[PJ_MAX_OBJ_NAME];  /**< Tsx name.  */
-    int                         tracing;        /**< Tracing enabled?       */
 
     /*
      * Transaction identification.
      */
+    char			obj_name[PJ_MAX_OBJ_NAME];  /**< Log info.  */
     pjsip_role_e		role;           /**< Role (UAS or UAC)      */
     pjsip_method		method;         /**< The method.            */
     int				cseq;           /**< The CSeq               */
-    pj_str_t			transaction_key;/**< hash table key.        */
+    pj_str_t			transaction_key;/**< Hash table key.        */
     pj_str_t			branch;         /**< The branch Id.         */
 
     /*
@@ -98,7 +82,8 @@ struct pjsip_transaction
      */
     int				status_code;    /**< Last status code seen. */
     pjsip_tsx_state_e		state;          /**< State.                 */
-    int				handle_ack;     /**< Should we handle ACK?  */
+    int				handle_200resp; /**< UAS 200/INVITE  retrsm.*/
+    int                         tracing;        /**< Tracing enabled?       */
 
     /** Handler according to current state. */
     pj_status_t (*state_handler)(struct pjsip_transaction *, pjsip_event *);
@@ -106,123 +91,115 @@ struct pjsip_transaction
     /*
      * Transport.
      */
-    pjsip_tsx_transport_state_e	transport_state;/**< Transport's state.     */
-    pjsip_host_info		dest_name;      /**< Destination address.   */
-    pjsip_server_addresses	remote_addr;    /**< Addresses resolved.    */
-    int				current_addr;   /**< Address currently used. */
-
     pjsip_transport	       *transport;      /**< Transport to use.      */
+    pj_sockaddr			addr;		/**< Destination address.   */
+    int				addr_len;	/**< Address length.	    */
+    pjsip_response_addr		res_addr;	/**< Response address.	    */
+    unsigned			transport_flag;	/**< Miscelaneous flag.	    */
 
     /*
      * Messages and timer.
      */
     pjsip_tx_data	       *last_tx;        /**< Msg kept for retrans.  */
-    int				has_unsent_msg; /**< Non-zero if tsx need to 
-                                                     transmit msg once resolver
-                                                     completes.             */
     int				retransmit_count;/**< Retransmission count. */
     pj_timer_entry		retransmit_timer;/**< Retransmit timer.     */
     pj_timer_entry		timeout_timer;  /**< Timeout timer.         */
 
     /** Module specific data. */
-    void		       *module_data[PJSIP_MAX_MODULE];
+    void		       *mod_data[PJSIP_MAX_MODULE];
 };
 
 
 /**
- * Create new transaction. Application would normally use 
- * #pjsip_endpt_create_tsx rather than this function.
- *
- * @param pool	    Pool to use by the transaction.
- * @param endpt	    Endpoint.
- * @param p_tsx	    Pointer to return the transaction.
- *
- * @return	    PJ_SUCCESS or the appropriate error code.
+ * Create and register transaction layer module to the specified endpoint.
  *
- * @see pjsip_endpt_create_tsx
+ * @param endpt	    The endpoint instance.
  *
+ * @return	    PJ_SUCCESS on success.
  */
-PJ_DEF(pj_status_t) pjsip_tsx_create( pj_pool_t *pool,
-				      pjsip_endpoint *endpt,
-				      pjsip_transaction **p_tsx);
-
-/** 
- * Init transaction as UAC from the specified transmit data (\c tdata).
- * The transmit data must have a valid \c Request-Line and \c CSeq header.
- * If \c Route headers are present, it will be used to calculate remote
- * destination.
- *
- * If \c Via header does not exist, it will be created along with a unique
- * \c branch parameter. If it exists and contains branch parameter, then
- * the \c branch parameter will be used as is as the transaction key.
- *
- * The \c Route headers in the transmit data, if present, are used to 
- * calculate remote destination.
- *
- * At the end of the function, the transaction will start resolving the
- * addresses of remote server to contact. Transport will be acquired as soon
- * as the resolving job completes.
- *
- * @param tsx       The transaction.
- * @param tdata     The transmit data.
+PJ_DECL(pj_status_t) pjsip_tsx_layer_init(pjsip_endpoint *endpt);
+
+/**
+ * Get the instance of the transaction layer module.
  *
- * @return          PJ_SUCCESS if successfull.
+ * @return	    The transaction layer module.
  */
-PJ_DECL(pj_status_t) pjsip_tsx_init_uac( pjsip_transaction *tsx, 
-					 pjsip_tx_data *tdata);
+PJ_DECL(pjsip_module*) pjsip_tsx_layer_instance(void);
 
 /**
- * Init transaction as UAS.
+ * Unregister and destroy transaction layer module.
  *
- * @param tsx       The transaction to be initialized.
- * @param rdata     The received incoming request.
- *
- * @return PJ_SUCCESS if successfull.
+ * @return	    PJ_SUCCESS on success.
  */
-PJ_DECL(pj_status_t) pjsip_tsx_init_uas( pjsip_transaction *tsx,
-					 pjsip_rx_data *rdata);
+PJ_DECL(pj_status_t) pjsip_tsx_layer_destroy(void);
 
 /**
- * Process incoming message for this transaction.
+ * Find a transaction with the specified key. The transaction key normally
+ * is created by calling #pjsip_tsx_create_key() from an incoming message.
  *
- * @param tsx       The transaction.
- * @param rdata     The incoming message.
+ * @param key	    The key string to find the transaction.
+ * @param lock	    If non-zero, transaction will be locked before the
+ *		    function returns, to make sure that it's not deleted
+ *		    by other threads.
+ *
+ * @return	    The matching transaction instance, or NULL if transaction
+ *		    can not be found.
  */
-PJ_DECL(void) pjsip_tsx_on_rx_msg( pjsip_transaction *tsx,
-				   pjsip_rx_data *rdata);
+PJ_DECL(pjsip_transaction*) pjsip_tsx_layer_find_tsx( const pj_str_t *key,
+						      pj_bool_t lock );
 
 /**
- * Transmit message with this transaction.
+ * Create, initialize, and register a new transaction as UAC from the 
+ * specified transmit data (\c tdata). The transmit data must have a valid
+ * \c Request-Line and \c CSeq header. 
  *
- * @param tsx       The transaction.
- * @param tdata     The outgoing message.
+ * If \c Via header does not exist, it will be created along with a unique
+ * \c branch parameter. If it exists and contains branch parameter, then
+ * the \c branch parameter will be used as is as the transaction key. If
+ * it exists but branch parameter doesn't exist, a unique branch parameter
+ * will be created.
+ *
+ * @param tsx_user  Module to be registered as transaction user of the new
+ *		    transaction, which will receive notification from the
+ *		    transaction via on_tsx_state() callback.
+ * @param tdata     The outgoing request message.
+ * @param p_tsx	    On return will contain the new transaction instance.
+ *
+ * @return          PJ_SUCCESS if successfull.
  */
-PJ_DECL(void) pjsip_tsx_on_tx_msg( pjsip_transaction *tsx,
-				   pjsip_tx_data *tdata);
-
+PJ_DECL(pj_status_t) pjsip_tsx_create_uac( pjsip_module *tsx_user,
+					   pjsip_tx_data *tdata,
+					   pjsip_transaction **p_tsx);
 
 /**
- * Transmit ACK message for 2xx/INVITE with this transaction. The ACK for
- * non-2xx/INVITE is automatically sent by the transaction.
- * This operation is only valid if the transaction is configured to handle ACK
- * (tsx->handle_ack is non-zero). If this attribute is not set, then the
- * transaction will comply with RFC-3261, i.e. it will set itself to 
- * TERMINATED state when it receives 2xx/INVITE.
+ * Create, initialize, and register a new transaction as UAS from the
+ * specified incoming request in \c rdata.
  *
- * @param tsx       The transaction.
- * @param tdata     The ACK request.
+ * @param tsx_user  Module to be registered as transaction user of the new
+ *		    transaction, which will receive notification from the
+ *		    transaction via on_tsx_state() callback.
+ * @param rdata     The received incoming request.
+ * @param p_tsx	    On return will contain the new transaction instance.
+ *
+ * @return	    PJ_SUCCESS if successfull.
  */
-PJ_DECL(void) pjsip_tsx_on_tx_ack( pjsip_transaction *tsx,
-				   pjsip_tx_data *tdata);
+PJ_DECL(pj_status_t) pjsip_tsx_create_uas( pjsip_module *tsx_user,
+					   pjsip_rx_data *rdata,
+					   pjsip_transaction **p_tsx );
 
 /**
- * Force terminate transaction.
+ * Transmit message in tdata with this transaction. It is possible to
+ * pass NULL in tdata for UAC transaction, which in this case the request
+ * message which was specified in #pjsip_tsx_create_uac() will be sent.
  *
  * @param tsx       The transaction.
- * @param code      The status code to report.
+ * @param tdata     The outgoing message.
+ *
+ * @return	    PJ_SUCCESS if successfull.
  */
-PJ_DECL(void) pjsip_tsx_terminate( pjsip_transaction *tsx,
-				   int code );
+PJ_DECL(pj_status_t) pjsip_tsx_send_msg( pjsip_transaction *tsx,
+					 pjsip_tx_data *tdata);
+
 
 /**
  * Create transaction key, which is used to match incoming requests 
@@ -244,6 +221,29 @@ PJ_DECL(pj_status_t) pjsip_tsx_create_key( pj_pool_t *pool,
 
 
 /**
+ * Force terminate transaction.
+ *
+ * @param tsx       The transaction.
+ * @param code      The status code to report.
+ */
+PJ_DECL(pj_status_t) pjsip_tsx_terminate( pjsip_transaction *tsx,
+					  int st_code );
+
+
+/**
+ * Get the transaction instance in the incoming message. If the message
+ * has a corresponding transaction, this function will return non NULL
+ * value.
+ *
+ * @param rdata	    The incoming message buffer.
+ *
+ * @return	    The transaction instance associated with this message,
+ *		    or NULL if the message doesn't match any transactions.
+ */
+PJ_DECL(pjsip_transaction*) pjsip_rdata_get_tsx( pjsip_rx_data *rdata );
+
+
+/**
  * @}
  */
 
@@ -262,9 +262,6 @@ PJ_DECL(const char *) pjsip_tsx_state_str(pjsip_tsx_state_e state);
 PJ_DECL(const char *) pjsip_role_name(pjsip_role_e role);
 
 
-/* Thread Local Storage ID for transaction lock (initialized by endpoint) */
-extern long pjsip_tsx_lock_tls_id;
-
 PJ_END_DECL
 
 #endif	/* __PJSIP_TRANSACT_H__ */
diff --git a/pjsip/include/pjsip/sip_transport.h b/pjsip/include/pjsip/sip_transport.h
index 6e6ba428..c296054c 100644
--- a/pjsip/include/pjsip/sip_transport.h
+++ b/pjsip/include/pjsip/sip_transport.h
@@ -171,7 +171,7 @@ struct pjsip_rx_data
 	pj_uint32_t		 zero;
 
 	/** The length of the packet received. */
-	int			 len;
+	pj_ssize_t		 len;
 
 	/** The source address from which the packet was received. */
 	pj_sockaddr		 src_addr;
@@ -251,9 +251,9 @@ struct pjsip_rx_data
     struct
     {
 	/** 
-	 * This the transaction key generated for the message. 
+	 * Data attached by modules to this message. 
 	 */
-	pj_str_t		 key;
+	void	*mod_data[PJSIP_MAX_MODULE];
 
     } endpt_info;
 
diff --git a/pjsip/include/pjsip/sip_transport_loop.h b/pjsip/include/pjsip/sip_transport_loop.h
new file mode 100644
index 00000000..bfcb93f4
--- /dev/null
+++ b/pjsip/include/pjsip/sip_transport_loop.h
@@ -0,0 +1,94 @@
+/* $Id$ */
+/* 
+ * Copyright (C) 2003-2006 Benny Prijono <benny@prijono.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
+ */
+#ifndef __PJSIP_TRANSPORT_LOOP_H__
+#define __PJSIP_TRANSPORT_LOOP_H__
+
+#include <pjsip/sip_transport.h>
+
+PJ_BEGIN_DECL
+
+/**
+ * Create and start datagram loop transport.
+ *
+ * @param endpt		The endpoint instance.
+ * @param transport	Pointer to receive the transport instance.
+ *
+ * @return		PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjsip_loop_start( pjsip_endpoint *endpt,
+				       pjsip_transport **transport);
+
+
+/**
+ * Enable/disable flag to discard any packets sent using the specified
+ * loop transport.
+ *
+ * @param tp		The loop transport.
+ * @param discard	If non-zero, any outgoing packets will be discarded.
+ * @param prev_value	Optional argument to receive previous value of
+ *			the discard flag.
+ *
+ * @return		PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjsip_loop_set_discard( pjsip_transport *tp,
+					     pj_bool_t discard,
+					     pj_bool_t *prev_value );
+
+
+/**
+ * Enable/disable flag to simulate network error. When this flag is set,
+ * outgoing transmission will return either immediate error or error via
+ * callback. If error is to be notified via callback, then the notification
+ * will occur after some delay, which is controlled by #pjsip_loop_set_delay().
+ *
+ * @param tp		The loop transport.
+ * @param fail_flag	If set to 1, the transport will return immediate error.
+ *			If set to 2, the transport will return error via
+ *			callback. If zero, the transport will deliver
+ *			the packet.
+ * @param prev_value	Optional argument to receive previous value of
+ *			the failure flag.
+ *
+ * @return		PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjsip_loop_set_failure( pjsip_transport *tp,
+					     int fail_flag,
+					     int *prev_value );
+
+
+/**
+ * Set delay (in miliseconds) before packet is delivered. This will also 
+ * control the delay for error notification callback.
+ *
+ * @param tp		The loop transport.
+ * @param delay		Delay, in miliseconds.
+ * @param prev_value	Optional argument to receive previous value of the
+ *			delay.
+ *
+ * @return		PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjsip_loop_set_delay( pjsip_transport *tp,
+					   unsigned delay,
+					   unsigned *prev_value);
+
+PJ_END_DECL
+
+
+#endif	/* __PJSIP_TRANSPORT_LOOP_H__ */
+
diff --git a/pjsip/include/pjsip/sip_types.h b/pjsip/include/pjsip/sip_types.h
index 516d50d5..72fe3af5 100644
--- a/pjsip/include/pjsip/sip_types.h
+++ b/pjsip/include/pjsip/sip_types.h
@@ -52,6 +52,12 @@ typedef enum pjsip_transport_type_e
     /** SCTP. */
     PJSIP_TRANSPORT_SCTP,
 
+    /** Loopback (stream, reliable) */
+    PJSIP_TRANSPORT_LOOP,
+
+    /** Loopback (datagram, unreliable) */
+    PJSIP_TRANSPORT_LOOP_DGRAM,
+
 } pjsip_transport_type_e;
 
 
diff --git a/pjsip/include/pjsip/sip_util.h b/pjsip/include/pjsip/sip_util.h
index ea0fcf3f..f0d55bdf 100644
--- a/pjsip/include/pjsip/sip_util.h
+++ b/pjsip/include/pjsip/sip_util.h
@@ -328,6 +328,29 @@ PJ_DECL(pj_status_t) pjsip_endpt_send_response( pjsip_endpoint *endpt,
 							   pj_bool_t *cont));
 
 /**
+ * This composite function sends response message statelessly to an incoming
+ * request message. Internally it calls #pjsip_endpt_create_response() and
+ * #pjsip_endpt_send_response().
+ *
+ * @param endpt	    The endpoint instance.
+ * @param rdata	    The incoming request message.
+ * @param st_code   Status code of the response.
+ * @param st_text   Optional status text of the response.
+ * @param hdr_list  Optional header list to be added to the response.
+ * @param body	    Optional message body to be added to the response.
+ *
+ * @return	    PJ_SUCCESS if response message has successfully been
+ *		    created.
+ */
+PJ_DECL(pj_status_t) pjsip_endpt_respond_stateless(pjsip_endpoint *endpt,
+						   pjsip_rx_data *rdata,
+						   int st_code,
+						   const pj_str_t *st_text,
+						   const pjsip_hdr *hdr_list,
+						   const pjsip_msg_body *body);
+						    
+
+/**
  * Send outgoing request and initiate UAC transaction for the request.
  * This is an auxiliary function to be used by application to send arbitrary
  * requests outside a dialog. To send a request within a dialog, application
@@ -352,6 +375,65 @@ PJ_DECL(pj_status_t) pjsip_endpt_send_request( pjsip_endpoint *endpt,
 					       void *token,
 					       void (*cb)(void*,pjsip_event*));
 
+/**
+ * Create new request message to be forwarded upstream to new destination URI 
+ * in uri. The new request is a full/deep clone of the request received in 
+ * rdata, unless if other copy mechanism is specified in the options. 
+ * The branch parameter, if not NULL, will be used as the branch-param in 
+ * the Via header. If it is NULL, then a unique branch parameter will be used.
+ *
+ * @param endpt	    The endpoint instance.
+ * @param rdata	    The incoming request message.
+ * @param uri	    The URI where the request will be forwarded to.
+ * @param branch    Optional branch parameter.
+ * @param options   Optional option flags when duplicating the message.
+ * @param tdata	    The result.
+ *
+ * @return	    PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjsip_endpt_create_request_fwd( pjsip_endpoint *endpt,
+						     pjsip_rx_data *rdata, 
+						     const pjsip_uri *uri,
+						     const pj_str_t *branch,
+						     unsigned options,
+						     pjsip_tx_data **tdata);
+
+/**
+ * Create new response message to be forwarded downstream by the proxy from 
+ * the response message found in rdata. Note that this function practically 
+ * will clone the response as is, i.e. without checking the validity of the 
+ * response or removing top most Via header. This function will perform 
+ * full/deep clone of the response, unless other copy mechanism is used in 
+ * the options.
+ *
+ * @param endpt	    The endpoint instance.
+ * @param rdata	    The incoming response message.
+ * @param options   Optional option flags when duplicate the message.
+ * @param tdata	    The result
+ *
+ * @return	    PJ_SUCCESS on success.
+ */
+PJ_DECL(pj_status_t) pjsip_endpt_create_response_fwd( pjsip_endpoint *endpt,
+						      pjsip_rx_data *rdata, 
+						      unsigned options,
+						      pjsip_tx_data **tdata);
+
+
+/**
+ * Create a globally unique branch parameter based on the information in 
+ * the incoming request message. This function guarantees that subsequent 
+ * retransmissions of the same request will generate the same branch id.
+ * This function can also be used in the loop detection process. 
+ * If the same request arrives back in the proxy with the same URL, it will
+ * calculate into the same branch id.
+ * Note that the returned string was allocated from rdata's pool.
+ *
+ * @param rdata	    The incoming request message.
+ *
+ * @return	    Unique branch-ID string.
+ */
+PJ_DECL(pj_str_t) pjsip_calculate_branch_id( pjsip_rx_data *rdata );
+
 
 /**
  * @}
diff --git a/pjsip/include/pjsip_core.h b/pjsip/include/pjsip_core.h
index 9f3c7e9b..5947d4b1 100644
--- a/pjsip/include/pjsip_core.h
+++ b/pjsip/include/pjsip_core.h
@@ -32,6 +32,7 @@
 #include <pjsip/sip_transaction.h>
 #include <pjsip/sip_transport.h>
 #include <pjsip/sip_transport_udp.h>
+#include <pjsip/sip_transport_loop.h>
 #include <pjsip/sip_uri.h>
 #include <pjsip/sip_util.h>