TS-4698: Adds an API call to identify WebSocket requests.

Add the TSHttpTxnIsWebsocket API to make it possible for plugins
to detect incoming WebSocket connections and thereby provide WebSocket
termination if desired.

This closes apache#822.

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

@@ -0,0 +1,45 @@
+.. Licensed to the Apache Software Foundation (ASF) under one
+   or more contributor license agreements.  See the NOTICE file
+   distributed with this work for additional information
+   regarding copyright ownership.  The ASF licenses this file
+   to you under the Apache License, Version 2.0 (the
+   "License"); you may not use this file except in compliance
+   with the License.  You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+.. default-domain:: c
+
+TSHttpTxnIsWebsocket
+********************
+
+Test whether a request is attempting to initiate Websocket connection.
+
+Synopsis
+========
+
+`#include <ts/ts.h>`
+
+.. function:: int TSHttpTxnIsWebsocket(TSHttpTxn txnp)
+
+Description
+===========
+
+:func:`TSHttpTxnIsWebsocket` tests whether the transaction
+is a WebSocket upgrade request.
+
+Return Values
+=============
+
+A non-zero value is returned if the relevant header value is found.
+
+See also
+========
+
+:manpage:`TSAPI(3ts)`

lib/atscppapi/src/InterceptPlugin.cc

@@ -254,6 +254,11 @@ InterceptPlugin::doRead()
   // Modify the input VIO to reflect how much data we've completed.
   TSVIONDoneSet(state_->input_.vio_, TSVIONDoneGet(state_->input_.vio_) + consumed);
 
+  if (isWebsocket()) {
+    TSVIOReenable(state_->input_.vio_);
+    return true;
+  }
+
   if ((state_->hdr_parsed_) && (state_->num_body_bytes_read_ >= state_->expected_body_size_)) {
     LOG_DEBUG("Completely read body");
     if (state_->num_body_bytes_read_ > state_->expected_body_size_) {

lib/atscppapi/src/TransactionPlugin.cc

@@ -72,6 +72,12 @@ TransactionPlugin::getMutex()
   return state_->mutex_;
 }
 
+bool
+TransactionPlugin::isWebsocket() const
+{
+  return TSHttpTxnIsWebsocket(state_->ats_txn_handle_);
+}
+
 TransactionPlugin::~TransactionPlugin()
 {
   LOG_DEBUG("Destroying TransactionPlugin=%p", this);

lib/atscppapi/src/include/atscppapi/TransactionPlugin.h

@@ -94,6 +94,8 @@ class TransactionPlugin : public Plugin
   void registerHook(Plugin::HookType hook_type);
   virtual ~TransactionPlugin();
 
+  bool isWebsocket() const;
+
 protected:
   TransactionPlugin(Transaction &transaction);
 

proxy/InkAPI.cc

@@ -4994,6 +4994,15 @@ TSHttpTxnInfoIntGet(TSHttpTxn txnp, TSHttpTxnInfoKey key, TSMgmtInt *value)
   return TS_SUCCESS;
 }
 
+int
+TSHttpTxnIsWebsocket(TSHttpTxn txnp)
+{
+  sdk_assert(sdk_sanity_check_txn(txnp) == TS_SUCCESS);
+
+  HttpSM *sm = (HttpSM *)txnp;
+  return sm->t_state.is_websocket;
+}
+
 TSReturnCode
 TSHttpTxnCacheLookupUrlGet(TSHttpTxn txnp, TSMBuffer bufp, TSMLoc obj)
 {

proxy/api/ts/ts.h

@@ -2334,6 +2334,7 @@ tsapi TSReturnCode TSHttpTxnCacheLookupUrlGet(TSHttpTxn txnp, TSMBuffer bufp, TS
 tsapi TSReturnCode TSHttpTxnCacheLookupUrlSet(TSHttpTxn txnp, TSMBuffer bufp, TSMLoc obj);
 tsapi TSReturnCode TSHttpTxnPrivateSessionSet(TSHttpTxn txnp, int private_session);
 tsapi int TSHttpTxnBackgroundFillStarted(TSHttpTxn txnp);
+tsapi int TSHttpTxnIsWebsocket(TSHttpTxn txnp);
 
 /* Get the Txn's (HttpSM's) unique identifier, which is a sequence number since server start) */
 tsapi uint64_t TSHttpTxnIdGet(TSHttpTxn txnp);