ARI/PJSIP: Add the ability to redirect (transfer) a channel in a Stasis app

This patch adds a new feature to ARI to redirect a channel to another server,
and fixes a few bugs in PJSIP's handling of the Transfer dialplan
application/ARI redirect capability.

*New Feature*
A new operation has been added to the ARI channels resource, redirect. With
this, a channel in a Stasis application can be redirected to another endpoint
of the same underlying channel technology.

*Bug fixes*
In the process of writing this new feature, two bugs were fixed in the PJSIP
stack:
(1) The existing .transfer channel callback had the limitation that it could
    only transfer channels to a SIP URI, i.e., you had to pass
    'PJSIP/sip:foo@my_provider.com' to the dialplan application. While this is
    still supported, it is somewhat unintuitive - particularly in a world full
    of endpoints. As such, we now also support specifying the PJSIP endpoint to
    transfer to.
(2) res_pjsip_multihomed was, unfortunately, trying to 'help' a 302 redirect by
    updating its Contact header. Alas, that resulted in the forwarding
    destination set by the dialplan application/ARI resource/whatever being
    rewritten with very incorrect information. Hence, we now don't bother
    updating an outgoing response if it is a 302. Since this took a looong time
    to find, some additional debug statements have been added to those modules
    that update the Contact headers.

Review: https://reviewboard.asterisk.org/r/4316/

ASTERISK-24015 #close
Reported by: Private Name

ASTERISK-24703 #close
Reported by: Matt Jordan



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@431717 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 26 insertions, 0 deletions

diff --git a/res/ari/resource_channels.h b/res/ari/resource_channels.h
index bd3b6205c..4d3ad5f8b 100644
--- a/res/ari/resource_channels.h
+++ b/res/ari/resource_channels.h
@@ -221,6 +221,32 @@ int ast_ari_channels_continue_in_dialplan_parse_body(
  * \param[out] response HTTP response
  */
 void ast_ari_channels_continue_in_dialplan(struct ast_variable *headers, struct ast_ari_channels_continue_in_dialplan_args *args, struct ast_ari_response *response);
+/*! Argument struct for ast_ari_channels_redirect() */
+struct ast_ari_channels_redirect_args {
+	/*! Channel's id */
+	const char *channel_id;
+	/*! The endpoint to redirect the channel to */
+	const char *endpoint;
+};
+/*!
+ * \brief Body parsing function for /channels/{channelId}/redirect.
+ * \param body The JSON body from which to parse parameters.
+ * \param[out] args The args structure to parse into.
+ * \retval zero on success
+ * \retval non-zero on failure
+ */
+int ast_ari_channels_redirect_parse_body(
+	struct ast_json *body,
+	struct ast_ari_channels_redirect_args *args);
+
+/*!
+ * \brief Redirect the channel to a different location.
+ *
+ * \param headers HTTP headers
+ * \param args Swagger parameters
+ * \param[out] response HTTP response
+ */
+void ast_ari_channels_redirect(struct ast_variable *headers, struct ast_ari_channels_redirect_args *args, struct ast_ari_response *response);
 /*! Argument struct for ast_ari_channels_answer() */
 struct ast_ari_channels_answer_args {
 	/*! Channel's id */