From 33a648d4c694b8951db2b664ca8d8edb0cb9da26 Mon Sep 17 00:00:00 2001
From: Torrey Searle <torrey@voxbone.com>
Date: Mon, 21 Aug 2017 11:28:52 +0200
Subject: [PATCH] res/res_pjsip_session: allow SDP answer to be regenerated
If an SDP answer hasn't been sent yet, it's legal to change it.
This is required for PJSIP_DTMF_MODE to work correctly, and can
also have use in the future for updating codecs too.
ASTERISK-27209 #close
Change-Id: Idbbfb7cb3f72fbd96c94d10d93540f69bd51e7a1
---
channels/pjsip/dialplan_functions.c | 5 +++-
include/asterisk/res_pjsip_session.h | 17 ++++++++++++
res/res_pjsip_session.c | 40 ++++++++++++++++++++++++++++
3 files changed, 61 insertions(+), 1 deletion(-)
diff --git a/channels/pjsip/dialplan_functions.c b/channels/pjsip/dialplan_functions.c
index c89d9ca262..93875b35c1 100644
--- a/channels/pjsip/dialplan_functions.c
+++ b/channels/pjsip/dialplan_functions.c
@@ -1241,10 +1241,13 @@ static int dtmf_mode_refresh_cb(void *obj)
struct refresh_data *data = obj;
if (data->session->inv_session->state == PJSIP_INV_STATE_CONFIRMED) {
- ast_debug(3, "Changing DTMF mode on channel %s after OFFER/ANSER completion. Sending session refresh\n", ast_channel_name(data->session->channel));
+ ast_debug(3, "Changing DTMF mode on channel %s after OFFER/ANSWER completion. Sending session refresh\n", ast_channel_name(data->session->channel));
ast_sip_session_refresh(data->session, NULL, NULL,
sip_session_response_cb, data->method, 1, NULL);
+ } else if (data->session->inv_session->state == PJSIP_INV_STATE_INCOMING) {
+ ast_debug(3, "Changing DTMF mode on channel %s during OFFER/ANSWER exchange. Updating SDP answer\n", ast_channel_name(data->session->channel));
+ ast_sip_session_regenerate_answer(data->session, NULL);
}
return 0;
diff --git a/include/asterisk/res_pjsip_session.h b/include/asterisk/res_pjsip_session.h
index 5f49c82371..d5b6fa194e 100644
--- a/include/asterisk/res_pjsip_session.h
+++ b/include/asterisk/res_pjsip_session.h
@@ -672,6 +672,23 @@ int ast_sip_session_refresh(struct ast_sip_session *session,
int generate_new_sdp,
struct ast_sip_session_media_state *media_state);
+/*!
+ * \brief Regenerate SDP Answer
+ *
+ * This method is used when an SDP offer has been received but an SDP answer
+ * has not been sent yet. It requests that a new local SDP be created and
+ * set as the SDP answer. As with any outgoing request in res_pjsip_session,
+ * this will call into registered supplements in case they wish to add anything.
+ *
+ * \param session The session on which the answer will be updated
+ * \param on_sdp_creation Callback called when SDP is created
+ * \param generate_new_sdp Boolean to indicate if a new SDP should be created
+ * \retval 0 Successfully updated the SDP answer
+ * \retval -1 Failure to updated the SDP answer
+ */
+int ast_sip_session_regenerate_answer(struct ast_sip_session *session,
+ ast_sip_session_sdp_creation_cb on_sdp_creation);
+
/*!
* \brief Send a SIP response
*
diff --git a/res/res_pjsip_session.c b/res/res_pjsip_session.c
index b6b8a21ac3..f6b3b937a1 100644
--- a/res/res_pjsip_session.c
+++ b/res/res_pjsip_session.c
@@ -1550,6 +1550,46 @@ int ast_sip_session_refresh(struct ast_sip_session *session,
return 0;
}
+int ast_sip_session_regenerate_answer(struct ast_sip_session *session,
+ ast_sip_session_sdp_creation_cb on_sdp_creation)
+{
+ pjsip_inv_session *inv_session = session->inv_session;
+ pjmedia_sdp_session *new_answer = NULL;
+ const pjmedia_sdp_session *previous_offer = NULL;
+
+ /* The SDP answer can only be regenerated if it is still pending to be sent */
+ if (!inv_session->neg || (pjmedia_sdp_neg_get_state(inv_session->neg) != PJMEDIA_SDP_NEG_STATE_REMOTE_OFFER &&
+ pjmedia_sdp_neg_get_state(inv_session->neg) != PJMEDIA_SDP_NEG_STATE_WAIT_NEGO)) {
+ ast_log(LOG_WARNING, "Requested to regenerate local SDP answer for channel '%s' but negotiation in state '%s'\n",
+ ast_channel_name(session->channel), pjmedia_sdp_neg_state_str(pjmedia_sdp_neg_get_state(inv_session->neg)));
+ return -1;
+ }
+
+ pjmedia_sdp_neg_get_neg_remote(inv_session->neg, &previous_offer);
+ if (pjmedia_sdp_neg_get_state(inv_session->neg) == PJMEDIA_SDP_NEG_STATE_WAIT_NEGO) {
+ /* Transition the SDP negotiator back to when it received the remote offer */
+ pjmedia_sdp_neg_negotiate(inv_session->pool, inv_session->neg, 0);
+ pjmedia_sdp_neg_set_remote_offer(inv_session->pool, inv_session->neg, previous_offer);
+ }
+
+ new_answer = create_local_sdp(inv_session, session, previous_offer);
+ if (!new_answer) {
+ ast_log(LOG_WARNING, "Could not create a new local SDP answer for channel '%s'\n",
+ ast_channel_name(session->channel));
+ return -1;
+ }
+
+ if (on_sdp_creation) {
+ if (on_sdp_creation(session, new_answer)) {
+ return -1;
+ }
+ }
+
+ pjsip_inv_set_sdp_answer(inv_session, new_answer);
+
+ return 0;
+}
+
void ast_sip_session_send_response(struct ast_sip_session *session, pjsip_tx_data *tdata)
{
handle_outgoing_response(session, tdata);
--
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