Change API to return a TSReturnCode code.

Return a TS_ERROR when we cannot push the url to the promise table.

Signed-off-by: David Calavera <david.calavera@gmail.com>

doc/developer-guide/api/functions/TSHttpTxnServerPush.en.rst

@@ -26,7 +26,7 @@ Synopsis
 
 `#include <ts/ts.h>`
 
-.. function:: void TSHttpTxnServerPush(TSHttpTxn txnp, const char *url, int url_len)
+.. function:: TSReturnCode TSHttpTxnServerPush(TSHttpTxn txnp, const char *url, int url_len)
 
 Description
 ===========
@@ -38,6 +38,9 @@ is not disabled by the client. You can call this API without checking whether
 Server Push is available on the transaction and it does nothing if Server Push
 is not available.
 
+This API returns an error if the URL to push is not valid, the client has Server Push disabled,
+or there is an error creating the H/2 PUSH_PROMISE frame.
+
 See Also
 ========
 

include/ts/ts.h

@@ -2542,7 +2542,7 @@ tsapi TSIOBufferReader TSHttpTxnPostBufferReaderGet(TSHttpTxn txnp);
  * @param url the URL string to preload.
  * @param url_len the length of the URL string.
  */
-tsapi void TSHttpTxnServerPush(TSHttpTxn txnp, const char *url, int url_len);
+tsapi TSReturnCode TSHttpTxnServerPush(TSHttpTxn txnp, const char *url, int url_len);
 
 #ifdef __cplusplus
 }

proxy/http2/Http2ConnectionState.cc

@@ -1639,7 +1639,7 @@ Http2ConnectionState::send_headers_frame(Http2Stream *stream)
   ats_free(buf);
 }
 
-void
+bool
 Http2ConnectionState::send_push_promise_frame(Http2Stream *stream, URL &url, const MIMEField *accept_encoding)
 {
   HTTPHdr h1_hdr, h2_hdr;
@@ -1651,7 +1651,7 @@ Http2ConnectionState::send_push_promise_frame(Http2Stream *stream, URL &url, con
   uint8_t flags               = 0x00;
 
   if (client_settings.get(HTTP2_SETTINGS_ENABLE_PUSH) == 0) {
-    return;
+    return false;
   }
 
   Http2StreamDebug(ua_session, stream->get_id(), "Send PUSH_PROMISE frame");
@@ -1681,14 +1681,14 @@ Http2ConnectionState::send_push_promise_frame(Http2Stream *stream, URL &url, con
   buf = static_cast<uint8_t *>(ats_malloc(buf_len));
   if (buf == nullptr) {
     h2_hdr.destroy();
-    return;
+    return false;
   }
   Http2ErrorCode result = http2_encode_header_blocks(&h2_hdr, buf, buf_len, &header_blocks_size, *(this->remote_hpack_handle),
                                                      client_settings.get(HTTP2_SETTINGS_HEADER_TABLE_SIZE));
   if (result != Http2ErrorCode::HTTP2_ERROR_NO_ERROR) {
     h2_hdr.destroy();
     ats_free(buf);
-    return;
+    return false;
   }
 
   // Send a PUSH_PROMISE frame
@@ -1736,7 +1736,7 @@ Http2ConnectionState::send_push_promise_frame(Http2Stream *stream, URL &url, con
   stream = this->create_stream(id, error);
   if (!stream) {
     h2_hdr.destroy();
-    return;
+    return false;
   }
 
   SCOPED_MUTEX_LOCK(stream_lock, stream->mutex, this_ethread());
@@ -1759,6 +1759,7 @@ Http2ConnectionState::send_push_promise_frame(Http2Stream *stream, URL &url, con
   stream->send_request(*this);
 
   h2_hdr.destroy();
+  return true;
 }
 
 void

proxy/http2/Http2ConnectionState.h

@@ -247,7 +247,7 @@ class Http2ConnectionState : public Continuation
   void send_data_frames(Http2Stream *stream);
   Http2SendDataFrameResult send_a_data_frame(Http2Stream *stream, size_t &payload_length);
   void send_headers_frame(Http2Stream *stream);
-  void send_push_promise_frame(Http2Stream *stream, URL &url, const MIMEField *accept_encoding);
+  bool send_push_promise_frame(Http2Stream *stream, URL &url, const MIMEField *accept_encoding);
   void send_rst_stream_frame(Http2StreamId id, Http2ErrorCode ec);
   void send_settings_frame(const Http2ConnectionSettings &new_settings);
   void send_ping_frame(Http2StreamId id, uint8_t flag, const uint8_t *opaque_data);

proxy/http2/Http2Stream.cc

@@ -711,12 +711,12 @@ Http2Stream::signal_write_event(bool call_update)
   }
 }
 
-void
+bool
 Http2Stream::push_promise(URL &url, const MIMEField *accept_encoding)
 {
   Http2ClientSession *_proxy_ssn = static_cast<Http2ClientSession *>(this->get_proxy_ssn());
   SCOPED_MUTEX_LOCK(lock, _proxy_ssn->connection_state.mutex, this_ethread());
-  _proxy_ssn->connection_state.send_push_promise_frame(this, url, accept_encoding);
+  return _proxy_ssn->connection_state.send_push_promise_frame(this, url, accept_encoding);
 }
 
 void

proxy/http2/Http2Stream.h

@@ -76,7 +76,7 @@ class Http2Stream : public ProxyTransaction
   void update_write_request(IOBufferReader *buf_reader, int64_t write_len, bool send_update);
   void signal_write_event(bool call_update);
   void restart_sending();
-  void push_promise(URL &url, const MIMEField *accept_encoding);
+  bool push_promise(URL &url, const MIMEField *accept_encoding);
 
   // Stream level window size
   ssize_t client_rwnd() const;

src/traffic_server/InkAPI.cc

@@ -8026,7 +8026,7 @@ TSHttpTxnIsInternal(TSHttpTxn txnp)
   return TSHttpSsnIsInternal(TSHttpTxnSsnGet(txnp));
 }
 
-void
+TSReturnCode
 TSHttpTxnServerPush(TSHttpTxn txnp, const char *url, int url_len)
 {
   sdk_assert(sdk_sanity_check_txn(txnp) == TS_SUCCESS);
@@ -8035,26 +8035,37 @@ TSHttpTxnServerPush(TSHttpTxn txnp, const char *url, int url_len)
   url_obj.create(nullptr);
   if (url_obj.parse(url, url_len) == PARSE_RESULT_ERROR) {
     url_obj.destroy();
-    return;
+    return TS_ERROR;
   }
 
   HttpSM *sm          = reinterpret_cast<HttpSM *>(txnp);
   Http2Stream *stream = dynamic_cast<Http2Stream *>(sm->ua_txn);
-  if (stream) {
-    Http2ClientSession *ua_session = static_cast<Http2ClientSession *>(stream->get_proxy_ssn());
-    SCOPED_MUTEX_LOCK(lock, ua_session->mutex, this_ethread());
-    if (!ua_session->connection_state.is_state_closed() && !ua_session->is_url_pushed(url, url_len)) {
-      HTTPHdr *hptr = &(sm->t_state.hdr_info.client_request);
-      TSMLoc obj    = reinterpret_cast<TSMLoc>(hptr->m_http);
-
-      MIMEHdrImpl *mh = _hdr_mloc_to_mime_hdr_impl(obj);
-      MIMEField *f    = mime_hdr_field_find(mh, MIME_FIELD_ACCEPT_ENCODING, MIME_LEN_ACCEPT_ENCODING);
-      stream->push_promise(url_obj, f);
-
-      ua_session->add_url_to_pushed_table(url, url_len);
-    }
+  if (stream == nullptr) {
+    url_obj.destroy();
+    return TS_ERROR;
+  }
+
+  Http2ClientSession *ua_session = static_cast<Http2ClientSession *>(stream->get_proxy_ssn());
+  SCOPED_MUTEX_LOCK(lock, ua_session->mutex, this_ethread());
+  if (ua_session->connection_state.is_state_closed() || ua_session->is_url_pushed(url, url_len)) {
+    url_obj.destroy();
+    return TS_ERROR;
   }
+
+  HTTPHdr *hptr = &(sm->t_state.hdr_info.client_request);
+  TSMLoc obj    = reinterpret_cast<TSMLoc>(hptr->m_http);
+
+  MIMEHdrImpl *mh = _hdr_mloc_to_mime_hdr_impl(obj);
+  MIMEField *f    = mime_hdr_field_find(mh, MIME_FIELD_ACCEPT_ENCODING, MIME_LEN_ACCEPT_ENCODING);
+  if (!stream->push_promise(url_obj, f)) {
+    url_obj.destroy();
+    return TS_ERROR;
+  }
+
+  ua_session->add_url_to_pushed_table(url, url_len);
+
   url_obj.destroy();
+  return TS_SUCCESS;
 }
 
 TSReturnCode