Make all of the various rtpqos parameters in this branch available from the CHANNEL function.

Also includes a test for retrieving rtpqos parameters, including a NULL RTP
driver.  Additionally, some further separation of the SIP internal API into
headers was necessary.

(closes issue #16652)
 Reported by: kkm
 Patches: 
       20100204__issue16652.diff.txt uploaded by tilghman (license 14)
 
Review: https://reviewboard.asterisk.org/r/501/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@247124 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/sip/include/sip_utils.h

@@ -22,8 +22,11 @@
 #ifndef _SIP_UTILS_H
 #define _SIP_UTILS_H
 
-/*! 
- * \brief converts ascii port to int representation. 
+/* wrapper macro to tell whether t points to one of the sip_tech descriptors */
+#define IS_SIP_TECH(t)  ((t) == &sip_tech || (t) == &sip_tech_info)
+
+/*!
+ * \brief converts ascii port to int representation.
  *
  * \arg pt[in] string that contains a port.
  * \arg standard[in] port to return in case the port string input is NULL
@@ -40,4 +43,41 @@ unsigned int port_str2int(const char *pt, unsigned int standard);
 const char *find_closing_quote(const char *start, const char *lim);
 
 
+/*! \brief Convert SIP hangup causes to Asterisk hangup causes */
+int hangup_sip2cause(int cause);
+
+/*! \brief Convert Asterisk hangup causes to SIP codes
+\verbatim
+ Possible values from causes.h
+        AST_CAUSE_NOTDEFINED    AST_CAUSE_NORMAL        AST_CAUSE_BUSY
+        AST_CAUSE_FAILURE       AST_CAUSE_CONGESTION    AST_CAUSE_UNALLOCATED
+
+	In addition to these, a lot of PRI codes is defined in causes.h
+	...should we take care of them too ?
+
+	Quote RFC 3398
+
+   ISUP Cause value                        SIP response
+   ----------------                        ------------
+   1  unallocated number                   404 Not Found
+   2  no route to network                  404 Not found
+   3  no route to destination              404 Not found
+   16 normal call clearing                 --- (*)
+   17 user busy                            486 Busy here
+   18 no user responding                   408 Request Timeout
+   19 no answer from the user              480 Temporarily unavailable
+   20 subscriber absent                    480 Temporarily unavailable
+   21 call rejected                        403 Forbidden (+)
+   22 number changed (w/o diagnostic)      410 Gone
+   22 number changed (w/ diagnostic)       301 Moved Permanently
+   23 redirection to new destination       410 Gone
+   26 non-selected user clearing           404 Not Found (=)
+   27 destination out of order             502 Bad Gateway
+   28 address incomplete                   484 Address incomplete
+   29 facility rejected                    501 Not implemented
+   31 normal unspecified                   480 Temporarily unavailable
+\endverbatim
+*/
+const char *hangup_cause2sip(int cause);
+
 #endif