TS-4042: Add feature to buffer request body before making downstream requests

Author: Zizhong Zhang

example/Makefile.am

@@ -32,6 +32,7 @@ example_Plugins = \
 	blacklist_0.la \
 	blacklist_1.la \
 	bnull_transform.la \
+	request_buffer.la \
 	cache_scan.la \
 	file_1.la \
 	hello.la \
@@ -98,6 +99,7 @@ basic_auth_la_SOURCES = basic_auth/basic_auth.c
 blacklist_0_la_SOURCES = blacklist_0/blacklist_0.c
 blacklist_1_la_SOURCES = blacklist_1/blacklist_1.c
 bnull_transform_la_SOURCES = bnull_transform/bnull_transform.c
+request_buffer_la_SOURCES = request_buffer/request_buffer.c
 cache_scan_la_SOURCES = cache_scan/cache_scan.cc
 file_1_la_SOURCES = file_1/file_1.c
 hello_la_SOURCES = hello/hello.c

example/request_buffer/request_buffer.c

@@ -0,0 +1,118 @@
+/** @file
+
+  A brief file description
+
+  @section license License
+
+  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.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ts/ts.h"
+#include "ts/ink_assert.h"
+#include "ts/ink_defs.h"
+
+#define PLUGIN_NAME "request_buffer"
+
+#define TS_NULL_MUTEX NULL
+
+static int
+request_buffer_plugin(TSCont contp, TSEvent event, void *edata)
+{
+  TSDebug(PLUGIN_NAME, "request_buffer_plugin starting, event[%d]", event);
+  TSHttpTxn txnp = (TSHttpTxn)(edata);
+  if (event == TS_EVENT_HTTP_REQUEST_BUFFER_COMPLETE) {
+    int len    = 0;
+    char *body = TSHttpTxnGetClientRequestBody(txnp, &len);
+    TSDebug(PLUGIN_NAME, "request_buffer_plugin gets the request body with length[%d]", len);
+    TSfree(body);
+    TSContDestroy(contp);
+  } else {
+    ink_assert(0);
+  }
+  return 0;
+}
+
+bool
+is_post_request(TSHttpTxn txnp)
+{
+  TSMLoc req_loc;
+  TSMBuffer req_bufp;
+  if (TSHttpTxnClientReqGet(txnp, &req_bufp, &req_loc) == TS_ERROR) {
+    TSError("Error while retrieving client request header\n");
+    return false;
+  }
+  int method_len     = 0;
+  const char *method = TSHttpHdrMethodGet(req_bufp, req_loc, &method_len);
+  if (method_len != (int)strlen(TS_HTTP_METHOD_POST) || strncasecmp(method, TS_HTTP_METHOD_POST, method_len) != 0) {
+    TSHandleMLocRelease(req_bufp, TS_NULL_MLOC, req_loc);
+    return false;
+  }
+  TSHandleMLocRelease(req_bufp, TS_NULL_MLOC, req_loc);
+  return true;
+}
+
+static int
+global_plugin(TSCont contp ATS_UNUSED, TSEvent event, void *edata)
+{
+  TSDebug(PLUGIN_NAME, "transform_plugin starting");
+  TSHttpTxn txnp = (TSHttpTxn)edata;
+
+  switch (event) {
+  case TS_EVENT_HTTP_READ_REQUEST_HDR:
+    if (is_post_request(txnp)) {
+      TSHttpTxnConfigIntSet(txnp, TS_CONFIG_HTTP_REQUEST_BUFFER_ENABLED, 1);
+      TSHttpTxnHookAdd(txnp, TS_HTTP_REQUEST_BUFFER_READ_COMPLETE_HOOK, TSContCreate(request_buffer_plugin, TSMutexCreate()));
+    }
+    TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
+    return 0;
+  default:
+    break;
+  }
+
+  return 0;
+}
+
+void
+TSPluginInit(int argc ATS_UNUSED, const char *argv[] ATS_UNUSED)
+{
+  TSPluginRegistrationInfo info;
+
+  info.plugin_name   = PLUGIN_NAME;
+  info.vendor_name   = "Apache Software Foundation";
+  info.support_email = "dev@trafficserver.apache.org";
+
+  if (TSPluginRegister(&info) != TS_SUCCESS) {
+    TSDebug(PLUGIN_NAME, "[%s] Plugin registration failed", PLUGIN_NAME);
+
+    goto Lerror;
+  }
+
+  /* This is call we could use if we need to protect global data */
+  /* TSReleaseAssert ((mutex = TSMutexCreate()) != TS_NULL_MUTEX); */
+
+  TSMutex mutex = TS_NULL_MUTEX;
+  TSHttpHookAdd(TS_HTTP_READ_REQUEST_HDR_HOOK, TSContCreate(global_plugin, mutex));
+  TSDebug(PLUGIN_NAME, "[%s] Plugin registration succeeded", PLUGIN_NAME);
+  return;
+
+Lerror:
+  TSDebug(PLUGIN_NAME, "[%s] Plugin disabled", PLUGIN_NAME);
+}

lib/ts/apidefs.h.in

@@ -293,6 +293,7 @@ typedef enum {
   TS_SSL_SERVER_VERIFY_HOOK,
   TS_SSL_SESSION_HOOK,
   TS_SSL_LAST_HOOK = TS_SSL_SESSION_HOOK,
+  TS_HTTP_REQUEST_BUFFER_READ_COMPLETE_HOOK,
   TS_HTTP_LAST_HOOK
 } TSHttpHookID;
 
@@ -451,6 +452,7 @@ typedef enum {
   TS_EVENT_LIFECYCLE_CLIENT_SSL_CTX_INITIALIZED = 60022,
   TS_EVENT_VCONN_PRE_ACCEPT                     = 60023,
   TS_EVENT_LIFECYCLE_MSG                        = 60024,
+  TS_EVENT_HTTP_REQUEST_BUFFER_COMPLETE         = 60025,
   TS_EVENT_MGMT_UPDATE                          = 60100,
   TS_EVENT_INTERNAL_60200                       = 60200,
   TS_EVENT_INTERNAL_60201                       = 60201,
@@ -762,6 +764,7 @@ typedef enum {
   TS_CONFIG_HTTP_PARENT_CONNECT_ATTEMPT_TIMEOUT,
   TS_CONFIG_HTTP_NORMALIZE_AE,
   TS_CONFIG_HTTP_INSERT_FORWARDED,
+  TS_CONFIG_HTTP_REQUEST_BUFFER_ENABLED,
   TS_CONFIG_LAST_ENTRY
 } TSOverridableConfigKey;
 

plugins/experimental/ts_lua/ts_lua_http_config.c

@@ -132,6 +132,7 @@ typedef enum {
   TS_LUA_CONFIG_HTTP_PARENT_PROXY_RETRY_TIME                  = TS_CONFIG_HTTP_PARENT_PROXY_RETRY_TIME,
   TS_LUA_CONFIG_HTTP_PER_PARENT_CONNECT_ATTEMPTS              = TS_CONFIG_HTTP_PER_PARENT_CONNECT_ATTEMPTS,
   TS_LUA_CONFIG_HTTP_PARENT_CONNECT_ATTEMPT_TIMEOUT           = TS_CONFIG_HTTP_PARENT_CONNECT_ATTEMPT_TIMEOUT,
+  TS_LUA_CONFIG_HTTP_REQUEST_BUFFER_ENABLED                   = TS_CONFIG_HTTP_REQUEST_BUFFER_ENABLED,
   TS_LUA_CONFIG_LAST_ENTRY                                    = TS_CONFIG_LAST_ENTRY,
 } TSLuaOverridableConfigKey;
 
@@ -256,6 +257,7 @@ ts_lua_var_item ts_lua_http_config_vars[] = {
   TS_LUA_MAKE_VAR_ITEM(TS_LUA_CONFIG_HTTP_PARENT_PROXY_RETRY_TIME),
   TS_LUA_MAKE_VAR_ITEM(TS_LUA_CONFIG_HTTP_PER_PARENT_CONNECT_ATTEMPTS),
   TS_LUA_MAKE_VAR_ITEM(TS_LUA_CONFIG_HTTP_PARENT_CONNECT_ATTEMPT_TIMEOUT),
+  TS_LUA_MAKE_VAR_ITEM(TS_LUA_CONFIG_HTTP_REQUEST_BUFFER_ENABLED),
   TS_LUA_MAKE_VAR_ITEM(TS_LUA_CONFIG_LAST_ENTRY),
 };
 

proxy/InkAPI.cc

@@ -8052,6 +8052,9 @@ _conf_to_memberp(TSOverridableConfigKey conf, OverridableHttpConfigParams *overr
   case TS_CONFIG_HTTP_POST_CHECK_CONTENT_LENGTH_ENABLED:
     ret = _memberp_to_generic(&overridableHttpConfig->post_check_content_length_enabled, typep);
     break;
+  case TS_CONFIG_HTTP_REQUEST_BUFFER_ENABLED:
+    ret = _memberp_to_generic(&overridableHttpConfig->request_buffer_enabled, typep);
+    break;
   case TS_CONFIG_HTTP_GLOBAL_USER_AGENT_HEADER:
     ret = _memberp_to_generic(&overridableHttpConfig->global_user_agent_header, typep);
     break;
@@ -8527,6 +8530,8 @@ TSHttpTxnConfigFind(const char *name, int length, TSOverridableConfigKey *conf,
     case 'd':
       if (!strncmp(name, "proxy.config.http.forward_connect_method", length)) {
         cnf = TS_CONFIG_HTTP_FORWARD_CONNECT_METHOD;
+      } else if (!strncmp(name, "proxy.config.http.request_buffer_enabled", length)) {
+        cnf = TS_CONFIG_HTTP_REQUEST_BUFFER_ENABLED;
       }
       break;
     case 'e':
@@ -9520,3 +9525,31 @@ TSRegisterProtocolTag(const char *tag)
 {
   return nullptr;
 }
+
+tsapi char *
+TSHttpTxnGetClientRequestBody(TSHttpTxn txnp, int *len)
+{
+  char *ret = NULL;
+
+  sdk_assert(sdk_sanity_check_txn(txnp) == TS_SUCCESS);
+  HttpSM *sm         = (HttpSM *)txnp;
+  int64_t read_avail = sm->post_buffer_reader->read_avail();
+  if (read_avail == 0)
+    return NULL;
+
+  ret = (char *)TSmalloc(sizeof(char) * read_avail);
+
+  int64_t consumed      = 0;
+  int64_t data_len      = 0;
+  const char *char_data = NULL;
+  TSIOBufferBlock block = TSIOBufferReaderStart((TSIOBufferReader)sm->post_buffer_reader);
+  while (block != NULL) {
+    char_data = TSIOBufferBlockReadStart(block, (TSIOBufferReader)sm->post_buffer_reader, &data_len);
+    memcpy(ret + consumed, char_data, data_len);
+    consumed += data_len;
+    block = TSIOBufferBlockNext(block);
+  }
+
+  *len = (int)consumed;
+  return ret;
+}

proxy/InkAPITest.cc

@@ -5546,6 +5546,7 @@ typedef enum {
   ORIG_TS_SSL_SERVER_VERIFY_HOOK,
   ORIG_TS_SSL_SESSION_HOOK,
   ORIG_TS_SSL_LAST_HOOK = ORIG_TS_SSL_SESSION_HOOK,
+  ORIG_TS_HTTP_REQUEST_BUFFER_READ_COMPLETE_HOOK,
   ORIG_TS_HTTP_LAST_HOOK
 } ORIG_TSHttpHookID;
 
@@ -7602,7 +7603,9 @@ const char *SDK_Overridable_Configs[TS_CONFIG_LAST_ENTRY] = {"proxy.config.url_r
                                                              "proxy.config.http.parent_proxy.per_parent_connect_attempts",
                                                              "proxy.config.http.parent_proxy.connect_attempts_timeout",
                                                              "proxy.config.http.normalize_ae",
-                                                             "proxy.config.http.insert_forwarded"};
+                                                             "proxy.config.http.insert_forwarded",
+                                                             "proxy.config.http.request_buffer_enabled",
+                                                             };
 
 REGRESSION_TEST(SDK_API_OVERRIDABLE_CONFIGS)(RegressionTest *test, int /* atype ATS_UNUSED */, int *pstatus)
 {

proxy/api/ts/ts.h

@@ -2441,6 +2441,17 @@ tsapi const char *TSHttpTxnClientProtocolStackContains(TSHttpTxn txnp, char cons
 tsapi const char *TSHttpSsnClientProtocolStackContains(TSHttpSsn ssnp, char const *tag);
 tsapi const char *TSNormalizedProtocolTag(char const *tag);
 tsapi const char *TSRegisterProtocolTag(char const *tag);
+/**
+   Get the body (if applicable) from a client request. YOU MUST
+   free the pointer returned from this call. This call will return
+   NULL if no body exists. Changes to this string will not affect
+   the request body. The second parameter will contain the length
+   of the string returned.
+
+   @return char * that contains the entire buffered request body, this
+       must be freed by the caller using TSFree!
+*/
+tsapi char *TSHttpTxnGetClientRequestBody(TSHttpTxn txnp, int *length);
 
 #ifdef __cplusplus
 }

proxy/http/HttpConfig.cc

@@ -957,6 +957,7 @@ HttpConfig::startup()
   HttpEstablishStaticConfigLongLong(c.oride.flow_high_water_mark, "proxy.config.http.flow_control.high_water");
   HttpEstablishStaticConfigLongLong(c.oride.flow_low_water_mark, "proxy.config.http.flow_control.low_water");
   HttpEstablishStaticConfigByte(c.oride.post_check_content_length_enabled, "proxy.config.http.post.check.content_length.enabled");
+  HttpEstablishStaticConfigByte(c.oride.request_buffer_enabled, "proxy.config.http.request_buffer_enabled");
   HttpEstablishStaticConfigByte(c.strict_uri_parsing, "proxy.config.http.strict_uri_parsing");
 
   // [amc] This is a bit of a mess, need to figure out to make this cleaner.
@@ -1237,6 +1238,8 @@ HttpConfig::reconfigure()
 
   params->oride.post_check_content_length_enabled = INT_TO_BOOL(m_master.oride.post_check_content_length_enabled);
 
+  params->oride.request_buffer_enabled = INT_TO_BOOL(m_master.oride.request_buffer_enabled);
+
   params->oride.flow_control_enabled = INT_TO_BOOL(m_master.oride.flow_control_enabled);
   params->oride.flow_high_water_mark = m_master.oride.flow_high_water_mark;
   params->oride.flow_low_water_mark  = m_master.oride.flow_low_water_mark;

proxy/http/HttpConfig.h

@@ -446,6 +446,7 @@ struct OverridableHttpConfigParams {
       parent_failures_update_hostdb(0),
       cache_open_write_fail_action(0),
       post_check_content_length_enabled(1),
+      request_buffer_enabled(0),
       ssl_client_verify_server(0),
       redirect_use_orig_cache_key(0),
       number_of_redirections(0),
@@ -619,6 +620,11 @@ struct OverridableHttpConfigParams {
   ////////////////////////
   MgmtByte post_check_content_length_enabled;
 
+  ////////////////////////////////////////////////
+  // Buffer post body before connecting servers //
+  ////////////////////////////////////////////////
+  MgmtByte request_buffer_enabled;
+
   /////////////////////////////
   // server verification mode//
   /////////////////////////////

proxy/http/HttpDebugNames.cc

@@ -360,6 +360,8 @@ HttpDebugNames::get_action_name(HttpTransact::StateMachineAction_t e)
     return ("SM_ACTION_DRAIN_REQUEST_BODY");
 #endif /* PROXY_DRAIN */
 
+  case HttpTransact::SM_ACTION_WAIT_FOR_FULL_BODY:
+    return ("SM_ACTION_WAIT_FOR_FULL_BODY");
   case HttpTransact::SM_ACTION_API_SM_START:
     return ("SM_ACTION_API_SM_START");
   case HttpTransact::SM_ACTION_REDIRECT_READ:
@@ -446,6 +448,8 @@ HttpDebugNames::get_api_hook_name(TSHttpHookID t)
     return "TS_HTTP_SEND_RESPONSE_HDR_HOOK";
   case TS_HTTP_REQUEST_TRANSFORM_HOOK:
     return "TS_HTTP_REQUEST_TRANSFORM_HOOK";
+  case TS_HTTP_REQUEST_BUFFER_READ_COMPLETE_HOOK:
+    return "TS_HTTP_REQUEST_BUFFER_READ_COMPLETE_HOOK";
   case TS_HTTP_RESPONSE_TRANSFORM_HOOK:
     return "TS_HTTP_RESPONSE_TRANSFORM_HOOK";
   case TS_HTTP_SELECT_ALT_HOOK: