func_channel: Reorganize documentation

* Following the example of the PJSIP channel driver, the channel
  technology specific documentation has been moved to the respective
  channel drivers that provide that functionality. This has the benefit
  of locating the documentation of items with those modules that provide
  it.

* Examples of using the CHANNEL function for both standard items as well
  as for PJSIP have been added.

* The 'max_forwards' standard item has been documented.

Change-Id: Ifaa79a232c8ac99cf8da6ef6cc7815d398b1b79b

4 files changed, 168 insertions, 0 deletions

diff --git a/channels/chan_dahdi.c b/channels/chan_dahdi.c
index b01fe8922..ac55f5864 100644
--- a/channels/chan_dahdi.c
+++ b/channels/chan_dahdi.c
@@ -180,6 +180,60 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 			<para>This application will Accept the R2 call either with charge or no charge.</para>
 		</description>
 	</application>
+	<info name="DAHDICHANNEL" language="en_US" tech="DAHDI">
+		<enumlist>
+			<enum name="dahdi_channel">
+				<para>R/O DAHDI channel related to this channel.</para>
+			</enum>
+			<enum name="dahdi_span">
+				<para>R/O DAHDI span related to this channel.</para>
+			</enum>
+			<enum name="dahdi_type">
+				<para>R/O DAHDI channel type, one of:</para>
+				<enumlist>
+					<enum name="analog" />
+					<enum name="mfc/r2" />
+					<enum name="pri" />
+					<enum name="pseudo" />
+					<enum name="ss7" />
+				</enumlist>
+			</enum>
+			<enum name="keypad_digits">
+				<para>R/O PRI Keypad digits that came in with the SETUP message.</para>
+			</enum>
+			<enum name="reversecharge">
+				<para>R/O PRI Reverse Charging Indication, one of:</para>
+				<enumlist>
+					<enum name="-1"> <para>None</para></enum>
+					<enum name=" 1"> <para>Reverse Charging Requested</para></enum>
+				</enumlist>
+			</enum>
+			<enum name="no_media_path">
+				<para>R/O PRI Nonzero if the channel has no B channel.
+				The channel is either on hold or a call waiting call.</para>
+			</enum>
+			<enum name="buffers">
+				<para>W/O Change the channel's buffer policy (for the current call only)</para>
+				<para>This option takes two arguments:</para>
+				<para>	Number of buffers,</para>
+				<para>	Buffer policy being one of:</para>
+				<para>	    <literal>full</literal></para>
+				<para>	    <literal>immediate</literal></para>
+				<para>	    <literal>half</literal></para>
+			</enum>
+			<enum name="echocan_mode">
+				<para>W/O Change the configuration of the active echo
+				canceller on the channel (if any), for the current call
+				only.</para>
+				<para>Possible values are:</para>
+				<para>	<literal>on</literal>	Normal mode (the echo canceller is actually reinitalized)</para>
+				<para>	<literal>off</literal>	Disabled</para>
+				<para>	<literal>fax</literal>	FAX/data mode (NLP disabled if possible, otherwise
+					completely disabled)</para>
+				<para>	<literal>voice</literal>	Voice mode (returns from FAX mode, reverting the changes that were made)</para>
+			</enum>
+		</enumlist>
+	</info>
 	<manager name="DAHDITransfer" language="en_US">
 		<synopsis>
 			Transfer DAHDI Channel.
diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index 8d5018d2c..bd773fc84 100644
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -213,6 +213,25 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 			<para>Gets or sets a variable that is sent to a remote IAX2 peer during call setup.</para>
 		</description>
 	</function>
+	<info name="IAXCHANNEL" language="en_US" tech="IAX">
+		<enumlist>
+			<enum name="osptoken">
+				<para>R/O Get the peer's osptoken.</para>
+			</enum>
+			<enum name="peerip">
+				<para>R/O Get the peer's ip address.</para>
+			</enum>
+			<enum name="peername">
+				<para>R/O Get the peer's username.</para>
+			</enum>
+			<enum name="secure_signaling">
+				<para>R/O Get the if the IAX channel is secured.</para>
+			</enum>
+			<enum name="secure_media">
+				<para>R/O Get the if the IAX channel is secured.</para>
+			</enum>
+		</enumlist>
+	</info>
 	<manager name="IAXpeers" language="en_US">
 		<synopsis>
 			List IAX peers.
diff --git a/channels/pjsip/dialplan_functions.c b/channels/pjsip/dialplan_functions.c
index 7962a7566..380a05eed 100644
--- a/channels/pjsip/dialplan_functions.c
+++ b/channels/pjsip/dialplan_functions.c
@@ -411,6 +411,19 @@
 		</enum>
 	</enumlist>
 </info>
+<info name="PJSIPCHANNEL_EXAMPLES" language="en_US" tech="PJSIP">
+	<example title="PJSIP specific CHANNEL examples">
+		; Log the current Call-ID
+		same => n,Log(NOTICE, ${CHANNEL(pjsip,call-id)})
+
+		; Log the destination address of the audio stream
+		same => n,Log(NOTICE, ${CHANNEL(rtp,dest)})
+
+		; Store the round-trip time associated with a
+		; video stream in the CDR field video-rtt
+		same => n,Set(CDR(video-rtt)=${CHANNEL(rtcp,rtt,video)})
+	</example>
+</info>
 ***/
 
 #include "asterisk.h"
diff --git a/channels/sip/dialplan_functions.c b/channels/sip/dialplan_functions.c
index 608f45697..e53981d65 100644
--- a/channels/sip/dialplan_functions.c
+++ b/channels/sip/dialplan_functions.c
@@ -23,6 +23,88 @@
 	<support_level>extended</support_level>
  ***/
 
+/*** DOCUMENTATION
+<info name="SIPCHANNEL" language="en_US" tech="SIP">
+	<enumlist>
+		<enum name="peerip">
+			<para>R/O Get the IP address of the peer.</para>
+		</enum>
+		<enum name="recvip">
+			<para>R/O Get the source IP address of the peer.</para>
+		</enum>
+		<enum name="recvport">
+			<para>R/O Get the source port of the peer.</para>
+		</enum>
+		<enum name="from">
+			<para>R/O Get the URI from the From: header.</para>
+		</enum>
+		<enum name="uri">
+			<para>R/O Get the URI from the Contact: header.</para>
+		</enum>
+		<enum name="useragent">
+			<para>R/O Get the useragent.</para>
+		</enum>
+		<enum name="peername">
+			<para>R/O Get the name of the peer.</para>
+		</enum>
+		<enum name="t38passthrough">
+			<para>R/O <literal>1</literal> if T38 is offered or enabled in this channel,
+			otherwise <literal>0</literal></para>
+		</enum>
+		<enum name="rtpqos">
+			<para>R/O Get QOS information about the RTP stream</para>
+			<para>    This option takes two additional arguments:</para>
+			<para>    Argument 1:</para>
+			<para>     <literal>audio</literal>             Get data about the audio stream</para>
+			<para>     <literal>video</literal>             Get data about the video stream</para>
+			<para>     <literal>text</literal>              Get data about the text stream</para>
+			<para>    Argument 2:</para>
+			<para>     <literal>local_ssrc</literal>        Local SSRC (stream ID)</para>
+			<para>     <literal>local_lostpackets</literal> Local lost packets</para>
+			<para>     <literal>local_jitter</literal>      Local calculated jitter</para>
+			<para>     <literal>local_maxjitter</literal>   Local calculated jitter (maximum)</para>
+			<para>     <literal>local_minjitter</literal>   Local calculated jitter (minimum)</para>
+			<para>     <literal>local_normdevjitter</literal>Local calculated jitter (normal deviation)</para>
+			<para>     <literal>local_stdevjitter</literal> Local calculated jitter (standard deviation)</para>
+			<para>     <literal>local_count</literal>       Number of received packets</para>
+			<para>     <literal>remote_ssrc</literal>       Remote SSRC (stream ID)</para>
+			<para>     <literal>remote_lostpackets</literal>Remote lost packets</para>
+			<para>     <literal>remote_jitter</literal>     Remote reported jitter</para>
+			<para>     <literal>remote_maxjitter</literal>  Remote calculated jitter (maximum)</para>
+			<para>     <literal>remote_minjitter</literal>  Remote calculated jitter (minimum)</para>
+			<para>     <literal>remote_normdevjitter</literal>Remote calculated jitter (normal deviation)</para>
+			<para>     <literal>remote_stdevjitter</literal>Remote calculated jitter (standard deviation)</para>
+			<para>     <literal>remote_count</literal>      Number of transmitted packets</para>
+			<para>     <literal>rtt</literal>               Round trip time</para>
+			<para>     <literal>maxrtt</literal>            Round trip time (maximum)</para>
+			<para>     <literal>minrtt</literal>            Round trip time (minimum)</para>
+			<para>     <literal>normdevrtt</literal>        Round trip time (normal deviation)</para>
+			<para>     <literal>stdevrtt</literal>          Round trip time (standard deviation)</para>
+			<para>     <literal>all</literal>               All statistics (in a form suited to logging,
+			but not for parsing)</para>
+		</enum>
+		<enum name="rtpdest">
+			<para>R/O Get remote RTP destination information.</para>
+			<para>   This option takes one additional argument:</para>
+			<para>    Argument 1:</para>
+			<para>     <literal>audio</literal>             Get audio destination</para>
+			<para>     <literal>video</literal>             Get video destination</para>
+			<para>     <literal>text</literal>              Get text destination</para>
+			<para>   Defaults to <literal>audio</literal> if unspecified.</para>
+		</enum>
+		<enum name="rtpsource">
+			<para>R/O Get source RTP destination information.</para>
+			<para>   This option takes one additional argument:</para>
+			<para>    Argument 1:</para>
+			<para>     <literal>audio</literal>             Get audio destination</para>
+			<para>     <literal>video</literal>             Get video destination</para>
+			<para>     <literal>text</literal>              Get text destination</para>
+			<para>   Defaults to <literal>audio</literal> if unspecified.</para>
+		</enum>
+	</enumlist>
+</info>
+ ***/
+
 #include "asterisk.h"
 
 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")