res_pjsip_t38.c: Be smarter about how we respond when T.38 is disabled.

We were blindly responding with AST_T38_REFUSED when ANY T.38 control
frame came accross the bridge.  This causes T.38 Gateway to get confused
and the T.38 session to get in a strange state.

* Made the T.38 framehook only respond to request frames and ignore
response frames.

ASTERISK-27657
ASTERISK-27080

Change-Id: I5fb5967c7d1efb30a7ff375f82887ca82a55b05b

diff --git a/res/res_pjsip_t38.c b/res/res_pjsip_t38.c
index 757c66711c9ed18faff8e6fae4fdd8974d47d205..598dd82ab58e11e4c53b720d97967f6b75246441 100644 (file)
--- a/res/res_pjsip_t38.c
+++ b/res/res_pjsip_t38.c
@@ -406,21 +406,42 @@ static int t38_interpret_parameters(void *obj)
 static struct ast_frame *t38_framehook_write(struct ast_channel *chan,
        struct ast_sip_session *session, struct ast_frame *f)
 {
-       if (f->frametype == AST_FRAME_CONTROL && f->subclass.integer == AST_CONTROL_T38_PARAMETERS) {
+       if (f->frametype == AST_FRAME_CONTROL
+               && f->subclass.integer == AST_CONTROL_T38_PARAMETERS) {
                if (session->endpoint->media.t38.enabled) {
-                       struct t38_parameters_task_data *data = t38_parameters_task_data_alloc(session, f);
+                       struct t38_parameters_task_data *data;
 
-                       if (!data) {
-                               return f;
-                       }
-
-                       if (ast_sip_push_task(session->serializer, t38_interpret_parameters, data)) {
+                       data = t38_parameters_task_data_alloc(session, f);
+                       if (data
+                               && ast_sip_push_task(session->serializer,
+                                       t38_interpret_parameters, data)) {
                                ao2_ref(data, -1);
                        }
                } else {
-                       struct ast_control_t38_parameters parameters = { .request_response = AST_T38_REFUSED, };
-                       ast_debug(2, "T.38 support not enabled, rejecting T.38 control packet\n");
-                       ast_queue_control_data(session->channel, AST_CONTROL_T38_PARAMETERS, &parameters, sizeof(parameters));
+                       static const struct ast_control_t38_parameters rsp_refused = {
+                               .request_response = AST_T38_REFUSED,
+                       };
+                       static const struct ast_control_t38_parameters rsp_terminated = {
+                               .request_response = AST_T38_TERMINATED,
+                       };
+                       const struct ast_control_t38_parameters *parameters = f->data.ptr;
+
+                       switch (parameters->request_response) {
+                       case AST_T38_REQUEST_NEGOTIATE:
+                               ast_debug(2, "T.38 support not enabled on %s, refusing T.38 negotiation\n",
+                                       ast_channel_name(chan));
+                               ast_queue_control_data(chan, AST_CONTROL_T38_PARAMETERS,
+                                       &rsp_refused, sizeof(rsp_refused));
+                               break;
+                       case AST_T38_REQUEST_TERMINATE:
+                               ast_debug(2, "T.38 support not enabled on %s, 'terminating' T.38 session\n",
+                                       ast_channel_name(chan));
+                               ast_queue_control_data(chan, AST_CONTROL_T38_PARAMETERS,
+                                       &rsp_terminated, sizeof(rsp_terminated));
+                               break;
+                       default:
+                               break;
+                       }
                }
        } else if (f->frametype == AST_FRAME_MODEM) {
                struct ast_sip_session_media *session_media;