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chan_pjsip: Incorporate channel reference count into transfer_refer(). 

Add channel reference count for PJSIP REFER. The call could be terminated
prior to the result of the transfer. In that scenario, when the SUBSCRIBE/NOTIFY
occurred several minutes later, it would attempt to access a session which was
no longer valid.  Terminate event subscription if pjsip_xfer_initiate() or
pjsip_xfer_send_request() fails in transfer_refer().

ASTERISK-29201 #close
Reported-by: Dan Cropp

Change-Id: I3fd92fd14b4e3844d3d7b0f60fe417a4df5f2435
This commit is contained in:
Dan Cropp 2020-12-07 16:59:51 -06:00 committed by Friendly Automation
parent 0e1ba9a778
commit fb23f98521
1 changed files with 26 additions and 18 deletions
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44
channels/chan_pjsip.c
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@ -1922,8 +1922,7 @@ static pjsip_module refer_callback_module = {
*/
static void xfer_client_on_evsub_state(pjsip_evsub *sub, pjsip_event *event)
{
struct ast_sip_session *session;
struct ast_channel *chan = NULL;
struct ast_channel *chan;
enum ast_control_transfer message = AST_TRANSFER_SUCCESS;
int res = 0;
@ -1931,12 +1930,7 @@ static void xfer_client_on_evsub_state(pjsip_evsub *sub, pjsip_event *event)
return;
}
session = pjsip_evsub_get_mod_data(sub, refer_callback_module.id);
if (!session) {
return;
}
chan = session->channel;
chan = pjsip_evsub_get_mod_data(sub, refer_callback_module.id);
if (!chan) {
return;
}
@ -1962,7 +1956,9 @@ static void xfer_client_on_evsub_state(pjsip_evsub *sub, pjsip_event *event)
*/
if (refer_sub && !pj_stricmp2(&refer_sub->hvalue, "false")) {
/* Since no subscription is desired, assume that call has been transferred successfully. */
/* Channel reference will be released at end of function */
/* Terminate subscription. */
pjsip_evsub_set_mod_data(sub, refer_callback_module.id, NULL);
pjsip_evsub_terminate(sub, PJ_TRUE);
res = -1;
}
@ -2027,7 +2023,8 @@ static void xfer_client_on_evsub_state(pjsip_evsub *sub, pjsip_event *event)
}
if (res) {
ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
ast_queue_control_data(chan, AST_CONTROL_TRANSFER, &message, sizeof(message));
ao2_ref(chan, -1);
}
}
@ -2040,28 +2037,29 @@ static void transfer_refer(struct ast_sip_session *session, const char *target)
const char *ref_by_val;
char local_info[pj_strlen(&session->inv_session->dlg->local.info_str) + 1];
struct pjsip_evsub_user xfer_cb;
struct ast_channel *chan = session->channel;
pj_bzero(&xfer_cb, sizeof(xfer_cb));
xfer_cb.on_evsub_state = &xfer_client_on_evsub_state;
if (pjsip_xfer_create_uac(session->inv_session->dlg, &xfer_cb, &sub) != PJ_SUCCESS) {
message = AST_TRANSFER_FAILED;
ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
ast_queue_control_data(chan, AST_CONTROL_TRANSFER, &message, sizeof(message));
return;
}
pjsip_evsub_set_mod_data(sub, refer_callback_module.id, session);
/* refer_callback_module requires a reference to chan
* which will be released in xfer_client_on_evsub_state()
* when the implicit REFER subscription terminates */
pjsip_evsub_set_mod_data(sub, refer_callback_module.id, chan);
ao2_ref(chan, +1);
if (pjsip_xfer_initiate(sub, pj_cstr(&tmp, target), &packet) != PJ_SUCCESS) {
message = AST_TRANSFER_FAILED;
ast_queue_control_data(session->channel, AST_CONTROL_TRANSFER, &message, sizeof(message));
pjsip_evsub_terminate(sub, PJ_FALSE);
return;
goto failure;
}
ref_by_val = pbx_builtin_getvar_helper(session->channel, "SIPREFERREDBYHDR");
ref_by_val = pbx_builtin_getvar_helper(chan, "SIPREFERREDBYHDR");
if (!ast_strlen_zero(ref_by_val)) {
ast_sip_add_header(packet, "Referred-By", ref_by_val);
} else {
@ -2069,7 +2067,17 @@ static void transfer_refer(struct ast_sip_session *session, const char *target)
ast_sip_add_header(packet, "Referred-By", local_info);
}
pjsip_xfer_send_request(sub, packet);
if (pjsip_xfer_send_request(sub, packet) == PJ_SUCCESS) {
return;
}
failure:
message = AST_TRANSFER_FAILED;
ast_queue_control_data(chan, AST_CONTROL_TRANSFER, &message, sizeof(message));
pjsip_evsub_set_mod_data(sub, refer_callback_module.id, NULL);
pjsip_evsub_terminate(sub, PJ_FALSE);
ao2_ref(chan, -1);
}
static int transfer(void *data)