From d9d1ed38227d0646eed979a8f12139ae517e5b5f Mon Sep 17 00:00:00 2001
From: file <file@f38db490-d61c-443f-a65b-d21fe96a405b>
Date: Mon, 18 Feb 2008 23:47:01 +0000
Subject: Add a non-invasive API for application level manipulation of T38 on a
 channel. This uses control frames (so they can even pass across IAX2) to
 negotiate T38 and provided a way of getting the current status of T38 using
 queryoption. This should by no means cause any issues and if it does I will
 take responsibility for it. (closes issue #11873) Reported by: dimas Patches:
       v4-t38-api.patch uploaded by dimas (license 88)

git-svn-id: http://svn.digium.com/svn/asterisk/trunk@103799 f38db490-d61c-443f-a65b-d21fe96a405b
---
 include/asterisk/channel.h | 27 +++++++++++++++++++++++++--
 include/asterisk/frame.h   | 15 +++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

(limited to 'include')

diff --git a/include/asterisk/channel.h b/include/asterisk/channel.h
index 0faddb870..e5fd5ba81 100644
--- a/include/asterisk/channel.h
+++ b/include/asterisk/channel.h
@@ -389,6 +389,17 @@ enum ast_channel_state {
 	AST_STATE_MUTE = (1 << 16),	/*!< Do not transmit voice data */
 };
 
+/*!
+ * \brief Possible T38 states on channels
+ */
+enum ast_t38_state {
+	T38_STATE_UNAVAILABLE,	/*!< T38 is unavailable on this channel or disabled by configuration */
+	T38_STATE_UNKNOWN,	/*!< The channel supports T38 but the current status is unknown */
+	T38_STATE_NEGOTIATING,	/*!< T38 is being negotiated */
+	T38_STATE_REJECTED,	/*!< Remote side has rejected our offer */
+	T38_STATE_NEGOTIATED,	/*!< T38 established */
+};
+
 /*! \brief Main Channel structure associated with a channel. 
  * This is the side of it mostly used by the pbx and call management.
  *
@@ -1300,10 +1311,10 @@ int ast_best_codec(int fmts);
 
 /*! Checks the value of an option */
 /*! 
- * Query the value of an option, optionally blocking until a reply is received
+ * Query the value of an option
  * Works similarly to setoption except only reads the options.
  */
-struct ast_frame *ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
+int ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
 
 /*! Checks for HTML support on a channel */
 /*! Returns 0 if channel does not support HTML or non-zero if it does */
@@ -1557,6 +1568,18 @@ static inline int ast_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds,
 #endif
 }
 
+/*! \brief Retrieves the current T38 state of a channel */
+static inline enum ast_t38_state ast_channel_get_t38_state(struct ast_channel *chan)
+{
+	enum ast_t38_state state = T38_STATE_UNAVAILABLE;
+	int datalen = sizeof(state);
+
+	ast_channel_queryoption(chan, AST_OPTION_T38_STATE, &state, &datalen, 0);
+
+	return state;
+}
+
+
 #ifdef DO_CRASH
 #define CRASH do { fprintf(stderr, "!! Forcing immediate crash a-la abort !!\n"); *((int *)0) = 0; } while(0)
 #else
diff --git a/include/asterisk/frame.h b/include/asterisk/frame.h
index 3983c84cf..012f7a952 100644
--- a/include/asterisk/frame.h
+++ b/include/asterisk/frame.h
@@ -292,6 +292,15 @@ enum ast_control_frame_type {
 	AST_CONTROL_HOLD = 16,		/*!< Indicate call is placed on hold */
 	AST_CONTROL_UNHOLD = 17,	/*!< Indicate call is left from hold */
 	AST_CONTROL_VIDUPDATE = 18,	/*!< Indicate video frame update */
+	AST_CONTROL_T38 = 19		/*!< T38 state change request/notification */
+};
+
+enum ast_control_t38 {
+	AST_T38_REQUEST_NEGOTIATE = 1,	/*!< Request T38 on a channel (voice to fax) */
+	AST_T38_REQUEST_TERMINATE,	/*!< Terminate T38 on a channel (fax to voice) */
+	AST_T38_NEGOTIATED,		/*!< T38 negotiated (fax mode) */
+	AST_T38_TERMINATED,		/*!< T38 terminated (back to voice) */
+	AST_T38_REFUSED			/*!< T38 refused for some reason (usually rejected by remote end) */
 };
 
 #define AST_SMOOTHER_FLAG_G729		(1 << 0)
@@ -340,6 +349,12 @@ enum ast_control_frame_type {
 /*! Explicitly enable or disable echo cancelation for the given channel */
 #define	AST_OPTION_ECHOCAN		8
 
+/* !
+ * Read-only. Allows query current status of T38 on the channel.
+ * data: ast_t38state
+ */
+#define AST_OPTION_T38_STATE		10
+
 struct oprmode {
 	struct ast_channel *peer;
 	int mode;
-- 
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