http: client POST method

Type: improvement

Change-Id: Iaa70abcee02866f9a6426a6e8e4709eeba0e8114
Signed-off-by: Matus Fabian <matfabia@cisco.com>

6 files changed, 722 insertions, 50 deletions

diff --git a/src/plugins/hs_apps/CMakeLists.txt b/src/plugins/hs_apps/CMakeLists.txt
index 3553a25837e..ba03e393f44 100644
--- a/src/plugins/hs_apps/CMakeLists.txt
+++ b/src/plugins/hs_apps/CMakeLists.txt
@@ -21,6 +21,7 @@ add_vpp_plugin(hs_apps
   hs_apps.c
   http_cli.c
   http_client_cli.c
+  http_simple_post.c
   http_tps.c
   proxy.c
   test_builtins.c
diff --git a/src/plugins/hs_apps/http_simple_post.c b/src/plugins/hs_apps/http_simple_post.c
new file mode 100644
index 00000000000..b0b9a38db2d
--- /dev/null
+++ b/src/plugins/hs_apps/http_simple_post.c
@@ -0,0 +1,569 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2024 Cisco Systems, Inc.
+ */
+
+#include <vnet/session/application.h>
+#include <vnet/session/application_interface.h>
+#include <vnet/session/session.h>
+#include <http/http.h>
+#include <http/http_header_names.h>
+#include <http/http_content_types.h>
+#include <vppinfra/unix.h>
+
+typedef struct
+{
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
+  u32 session_index;
+  u32 thread_index;
+  u32 vpp_session_index;
+  u8 is_closed;
+} hsp_session_t;
+
+typedef struct
+{
+  hsp_session_t *sessions;
+  u32 thread_index;
+} hsp_worker_t;
+
+typedef struct
+{
+  u32 app_index;
+  vlib_main_t *vlib_main;
+  u32 cli_node_index;
+  u8 attached;
+  u8 *uri;
+  session_endpoint_cfg_t connect_sep;
+  u8 *target;
+  u8 *headers_buf;
+  u8 *data;
+  u32 data_offset;
+  hsp_worker_t *wrk;
+  u8 *http_response;
+  u8 is_file;
+  u8 use_ptr;
+} hsp_main_t;
+
+typedef enum
+{
+  HSP_CONNECT_FAILED = 1,
+  HSP_TRANSPORT_CLOSED,
+  HSP_REPLY_RECEIVED,
+} hsp_cli_signal_t;
+
+static hsp_main_t hsp_main;
+
+static inline hsp_worker_t *
+hsp_worker_get (u32 thread_index)
+{
+  return &hsp_main.wrk[thread_index];
+}
+
+static inline hsp_session_t *
+hsp_session_get (u32 session_index, u32 thread_index)
+{
+  hsp_worker_t *wrk = hsp_worker_get (thread_index);
+  return pool_elt_at_index (wrk->sessions, session_index);
+}
+
+static hsp_session_t *
+hsp_session_alloc (hsp_worker_t *wrk)
+{
+  hsp_session_t *s;
+
+  pool_get_zero (wrk->sessions, s);
+  s->session_index = s - wrk->sessions;
+  s->thread_index = wrk->thread_index;
+
+  return s;
+}
+
+static int
+hsp_session_connected_callback (u32 app_index, u32 hsp_session_index,
+				session_t *s, session_error_t err)
+{
+  hsp_main_t *hspm = &hsp_main;
+  hsp_session_t *hsp_session, *new_hsp_session;
+  hsp_worker_t *wrk;
+  http_header_t *headers = 0;
+  http_msg_t msg;
+  int rv;
+
+  if (err)
+    {
+      clib_warning ("hsp_session_index[%d] connected error: %U",
+		    hsp_session_index, format_session_error, err);
+      vlib_process_signal_event_mt (hspm->vlib_main, hspm->cli_node_index,
+				    HSP_CONNECT_FAILED, 0);
+      return -1;
+    }
+
+  hsp_session = hsp_session_get (hsp_session_index, 0);
+  wrk = hsp_worker_get (s->thread_index);
+  new_hsp_session = hsp_session_alloc (wrk);
+  clib_memcpy_fast (new_hsp_session, hsp_session, sizeof (*hsp_session));
+  hsp_session->vpp_session_index = s->session_index;
+
+  if (hspm->is_file)
+    {
+      http_add_header (
+	&headers, http_header_name_token (HTTP_HEADER_CONTENT_TYPE),
+	http_content_type_token (HTTP_CONTENT_APP_OCTET_STREAM));
+    }
+  else
+    {
+      http_add_header (
+	&headers, http_header_name_token (HTTP_HEADER_CONTENT_TYPE),
+	http_content_type_token (HTTP_CONTENT_APP_X_WWW_FORM_URLENCODED));
+    }
+  hspm->headers_buf = http_serialize_headers (headers);
+  vec_free (headers);
+
+  msg.type = HTTP_MSG_REQUEST;
+  msg.method_type = HTTP_REQ_POST;
+  /* request target */
+  msg.data.target_form = HTTP_TARGET_ORIGIN_FORM;
+  msg.data.target_path_len = vec_len (hspm->target);
+  /* custom headers */
+  msg.data.headers_len = vec_len (hspm->headers_buf);
+  /* request body */
+  msg.data.body_len = vec_len (hspm->data);
+  /* total length */
+  msg.data.len =
+    msg.data.target_path_len + msg.data.headers_len + msg.data.body_len;
+
+  if (hspm->use_ptr)
+    {
+      uword target = pointer_to_uword (hspm->target);
+      uword headers = pointer_to_uword (hspm->headers_buf);
+      uword body = pointer_to_uword (hspm->data);
+      msg.data.type = HTTP_MSG_DATA_PTR;
+      svm_fifo_seg_t segs[4] = {
+	{ (u8 *) &msg, sizeof (msg) },
+	{ (u8 *) &target, sizeof (target) },
+	{ (u8 *) &headers, sizeof (headers) },
+	{ (u8 *) &body, sizeof (body) },
+      };
+
+      rv =
+	svm_fifo_enqueue_segments (s->tx_fifo, segs, 4, 0 /* allow partial */);
+      ASSERT (rv == (sizeof (msg) + sizeof (target) + sizeof (headers) +
+		     sizeof (body)));
+      goto done;
+    }
+
+  msg.data.type = HTTP_MSG_DATA_INLINE;
+  msg.data.target_path_offset = 0;
+  msg.data.headers_offset = msg.data.target_path_len;
+  msg.data.body_offset = msg.data.headers_offset + msg.data.headers_len;
+
+  rv = svm_fifo_enqueue (s->tx_fifo, sizeof (msg), (u8 *) &msg);
+  ASSERT (rv == sizeof (msg));
+
+  rv = svm_fifo_enqueue (s->tx_fifo, vec_len (hspm->target), hspm->target);
+  ASSERT (rv == vec_len (hspm->target));
+
+  rv = svm_fifo_enqueue (s->tx_fifo, vec_len (hspm->headers_buf),
+			 hspm->headers_buf);
+  ASSERT (rv == msg.data.headers_len);
+
+  rv = svm_fifo_enqueue (s->tx_fifo, vec_len (hspm->data), hspm->data);
+  if (rv != vec_len (hspm->data))
+    {
+      hspm->data_offset = (rv > 0) ? rv : 0;
+      svm_fifo_add_want_deq_ntf (s->tx_fifo, SVM_FIFO_WANT_DEQ_NOTIF);
+    }
+
+done:
+  if (svm_fifo_set_event (s->tx_fifo))
+    session_program_tx_io_evt (s->handle, SESSION_IO_EVT_TX);
+
+  return 0;
+}
+
+static void
+hsp_session_disconnect_callback (session_t *s)
+{
+  hsp_main_t *hspm = &hsp_main;
+  vnet_disconnect_args_t _a = { 0 }, *a = &_a;
+  int rv;
+
+  a->handle = session_handle (s);
+  a->app_index = hspm->app_index;
+  if ((rv = vnet_disconnect_session (a)))
+    clib_warning ("warning: disconnect returned: %U", format_session_error,
+		  rv);
+}
+
+static void
+hsp_session_transport_closed_callback (session_t *s)
+{
+  hsp_main_t *hspm = &hsp_main;
+
+  vlib_process_signal_event_mt (hspm->vlib_main, hspm->cli_node_index,
+				HSP_TRANSPORT_CLOSED, 0);
+}
+
+static void
+hsp_session_reset_callback (session_t *s)
+{
+  hsp_main_t *hspm = &hsp_main;
+  hsp_session_t *hsp_session;
+  vnet_disconnect_args_t _a = { 0 }, *a = &_a;
+  int rv;
+
+  hsp_session = hsp_session_get (s->opaque, s->thread_index);
+  hsp_session->is_closed = 1;
+
+  a->handle = session_handle (s);
+  a->app_index = hspm->app_index;
+  if ((rv = vnet_disconnect_session (a)))
+    clib_warning ("warning: disconnect returned: %U", format_session_error,
+		  rv);
+}
+
+static int
+hsp_rx_callback (session_t *s)
+{
+  hsp_main_t *hspm = &hsp_main;
+  hsp_session_t *hsp_session;
+  http_msg_t msg;
+  int rv;
+
+  hsp_session = hsp_session_get (s->opaque, s->thread_index);
+
+  if (hsp_session->is_closed)
+    {
+      clib_warning ("hsp_session_index[%d] is closed", s->opaque);
+      return -1;
+    }
+
+  rv = svm_fifo_dequeue (s->rx_fifo, sizeof (msg), (u8 *) &msg);
+  ASSERT (rv == sizeof (msg));
+
+  if (msg.type != HTTP_MSG_REPLY)
+    {
+      clib_warning ("unexpected msg type %d", msg.type);
+      return -1;
+    }
+
+  svm_fifo_dequeue_drop_all (s->rx_fifo);
+
+  if (msg.code == HTTP_STATUS_OK)
+    hspm->http_response = format (0, "request success");
+  else
+    hspm->http_response = format (0, "request failed");
+
+  hsp_session_disconnect_callback (s);
+  vlib_process_signal_event_mt (hspm->vlib_main, hspm->cli_node_index,
+				HSP_REPLY_RECEIVED, 0);
+  return 0;
+}
+
+static int
+hsp_tx_callback (session_t *s)
+{
+  hsp_main_t *hspm = &hsp_main;
+  u32 to_send;
+  int rv;
+
+  to_send = vec_len (hspm->data) - hspm->data_offset;
+  rv = svm_fifo_enqueue (s->tx_fifo, to_send, hspm->data + hspm->data_offset);
+
+  if (rv <= 0)
+    {
+      svm_fifo_add_want_deq_ntf (s->tx_fifo, SVM_FIFO_WANT_DEQ_NOTIF);
+      return 0;
+    }
+
+  if (rv < to_send)
+    {
+      hspm->data_offset += rv;
+      svm_fifo_add_want_deq_ntf (s->tx_fifo, SVM_FIFO_WANT_DEQ_NOTIF);
+    }
+
+  if (svm_fifo_set_event (s->tx_fifo))
+    session_program_tx_io_evt (s->handle, SESSION_IO_EVT_TX);
+
+  return 0;
+}
+
+static session_cb_vft_t hsp_session_cb_vft = {
+  .session_connected_callback = hsp_session_connected_callback,
+  .session_disconnect_callback = hsp_session_disconnect_callback,
+  .session_transport_closed_callback = hsp_session_transport_closed_callback,
+  .session_reset_callback = hsp_session_reset_callback,
+  .builtin_app_rx_callback = hsp_rx_callback,
+  .builtin_app_tx_callback = hsp_tx_callback,
+};
+
+static clib_error_t *
+hsp_attach ()
+{
+  hsp_main_t *hspm = &hsp_main;
+  vnet_app_attach_args_t _a, *a = &_a;
+  u64 options[18];
+  int rv;
+
+  clib_memset (a, 0, sizeof (*a));
+  clib_memset (options, 0, sizeof (options));
+
+  a->api_client_index = APP_INVALID_INDEX;
+  a->name = format (0, "http_simple_post");
+  a->session_cb_vft = &hsp_session_cb_vft;
+  a->options = options;
+  a->options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;
+
+  if ((rv = vnet_application_attach (a)))
+    return clib_error_return (0, "attach returned: %U", format_session_error,
+			      rv);
+
+  hspm->app_index = a->app_index;
+  vec_free (a->name);
+  hspm->attached = 1;
+
+  return 0;
+}
+
+static int
+hsp_connect_rpc (void *rpc_args)
+{
+  vnet_connect_args_t *a = rpc_args;
+  int rv;
+
+  rv = vnet_connect (a);
+  if (rv)
+    clib_warning (0, "connect returned: %U", format_session_error, rv);
+
+  vec_free (a);
+  return rv;
+}
+
+static void
+hsp_connect ()
+{
+  hsp_main_t *hspm = &hsp_main;
+  vnet_connect_args_t *a = 0;
+  hsp_worker_t *wrk;
+  hsp_session_t *hsp_session;
+
+  vec_validate (a, 0);
+  clib_memset (a, 0, sizeof (a[0]));
+
+  clib_memcpy (&a->sep_ext, &hspm->connect_sep, sizeof (hspm->connect_sep));
+  a->app_index = hspm->app_index;
+
+  /* allocate http session on main thread */
+  wrk = hsp_worker_get (0);
+  hsp_session = hsp_session_alloc (wrk);
+  a->api_context = hsp_session->session_index;
+
+  session_send_rpc_evt_to_thread_force (transport_cl_thread (),
+					hsp_connect_rpc, a);
+}
+
+static clib_error_t *
+hsp_run (vlib_main_t *vm)
+{
+  hsp_main_t *hspm = &hsp_main;
+  vlib_thread_main_t *vtm = vlib_get_thread_main ();
+  u32 num_threads;
+  hsp_worker_t *wrk;
+  uword event_type, *event_data = 0;
+  clib_error_t *err;
+
+  num_threads = 1 /* main thread */ + vtm->n_threads;
+  vec_validate (hspm->wrk, num_threads);
+  vec_foreach (wrk, hspm->wrk)
+    wrk->thread_index = wrk - hspm->wrk;
+
+  if ((err = hsp_attach ()))
+    return clib_error_return (0, "http simple post attach: %U",
+			      format_clib_error, err);
+
+  hsp_connect ();
+
+  vlib_process_wait_for_event_or_clock (vm, 10);
+  event_type = vlib_process_get_events (vm, &event_data);
+  switch (event_type)
+    {
+    case ~0:
+      err = clib_error_return (0, "error: timeout");
+      break;
+    case HSP_CONNECT_FAILED:
+      err = clib_error_return (0, "error: failed to connect");
+      break;
+    case HSP_TRANSPORT_CLOSED:
+      err = clib_error_return (0, "error: transport closed");
+      break;
+    case HSP_REPLY_RECEIVED:
+      vlib_cli_output (vm, "%v", hspm->http_response);
+      break;
+    default:
+      err = clib_error_return (0, "error: unexpected event %d", event_type);
+      break;
+    }
+
+  vec_free (event_data);
+  return err;
+}
+
+static int
+hsp_detach ()
+{
+  hsp_main_t *hspm = &hsp_main;
+  vnet_app_detach_args_t _da, *da = &_da;
+  int rv;
+
+  if (!hspm->attached)
+    return 0;
+
+  da->app_index = hspm->app_index;
+  da->api_client_index = APP_INVALID_INDEX;
+  rv = vnet_application_detach (da);
+  hspm->attached = 0;
+  hspm->app_index = APP_INVALID_INDEX;
+
+  return rv;
+}
+
+static void
+hcc_worker_cleanup (hsp_worker_t *wrk)
+{
+  pool_free (wrk->sessions);
+}
+
+static void
+hsp_cleanup ()
+{
+  hsp_main_t *hspm = &hsp_main;
+  hsp_worker_t *wrk;
+
+  vec_foreach (wrk, hspm->wrk)
+    hcc_worker_cleanup (wrk);
+
+  vec_free (hspm->uri);
+  vec_free (hspm->target);
+  vec_free (hspm->headers_buf);
+  vec_free (hspm->data);
+  vec_free (hspm->http_response);
+  vec_free (hspm->wrk);
+}
+
+static clib_error_t *
+hsp_command_fn (vlib_main_t *vm, unformat_input_t *input,
+		vlib_cli_command_t *cmd)
+{
+  hsp_main_t *hspm = &hsp_main;
+  clib_error_t *err = 0;
+  unformat_input_t _line_input, *line_input = &_line_input;
+  u8 *path = 0;
+  u8 *file_data;
+  int rv;
+
+  if (hspm->attached)
+    return clib_error_return (0, "failed: already running!");
+
+  hspm->use_ptr = 0;
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return clib_error_return (0, "expected required arguments");
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "uri %s", &hspm->uri))
+	;
+      else if (unformat (line_input, "data %v", &hspm->data))
+	hspm->is_file = 0;
+      else if (unformat (line_input, "target %s", &hspm->target))
+	;
+      else if (unformat (line_input, "file %s", &path))
+	hspm->is_file = 1;
+      else if (unformat (line_input, "use-ptr"))
+	hspm->use_ptr = 1;
+      else
+	{
+	  err = clib_error_return (0, "unknown input `%U'",
+				   format_unformat_error, line_input);
+	  goto done;
+	}
+    }
+
+  if (!hspm->uri)
+    {
+      err = clib_error_return (0, "URI not defined");
+      goto done;
+    }
+  if (!hspm->target)
+    {
+      err = clib_error_return (0, "target not defined");
+      goto done;
+    }
+  if (!hspm->data)
+    {
+      if (path)
+	{
+	  err = clib_file_contents ((char *) path, &file_data);
+	  if (err)
+	    goto done;
+	  hspm->data = file_data;
+	}
+      else
+	{
+	  err = clib_error_return (0, "data not defined");
+	  goto done;
+	}
+    }
+
+  if ((rv = parse_uri ((char *) hspm->uri, &hspm->connect_sep)))
+    {
+      err =
+	clib_error_return (0, "URI parse error: %U", format_session_error, rv);
+      goto done;
+    }
+
+  vlib_worker_thread_barrier_sync (vm);
+  vnet_session_enable_disable (vm, 1 /* turn on TCP, etc. */);
+  vlib_worker_thread_barrier_release (vm);
+
+  hspm->cli_node_index =
+    vlib_get_current_process (vm)->node_runtime.node_index;
+
+  err = hsp_run (vm);
+
+  if ((rv = hsp_detach ()))
+    {
+      /* don't override last error */
+      if (!err)
+	err = clib_error_return (0, "detach returned: %U",
+				 format_session_error, rv);
+      else
+	clib_warning ("warning: detach returned: %U", format_session_error,
+		      rv);
+    }
+
+done:
+  hsp_cleanup ();
+  unformat_free (line_input);
+  return err;
+}
+
+VLIB_CLI_COMMAND (hsp_command, static) = {
+  .path = "http post",
+  .short_help = "uri http://<ip-addr> target <origin-form> "
+		"[data <form-urlencoded> | file <file-path>] [use-ptr]",
+  .function = hsp_command_fn,
+  .is_mp_safe = 1,
+};
+
+static clib_error_t *
+hsp_main_init (vlib_main_t *vm)
+{
+  hsp_main_t *hspm = &hsp_main;
+
+  hspm->app_index = APP_INVALID_INDEX;
+  hspm->vlib_main = vm;
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (hsp_main_init);
\ No newline at end of file
diff --git a/src/plugins/http/http.c b/src/plugins/http/http.c
index 017fd50ebae..c504b0c5028 100644
--- a/src/plugins/http/http.c
+++ b/src/plugins/http/http.c
@@ -385,10 +385,16 @@ static const char *http_response_template = "HTTP/1.1 %s\r\n"
 /**
  * http request boilerplate
  */
-static const char *http_request_template = "GET %s HTTP/1.1\r\n"
-					   "Host: %v\r\n"
-					   "User-Agent: %v\r\n"
-					   "%s";
+static const char *http_get_request_template = "GET %s HTTP/1.1\r\n"
+					       "Host: %v\r\n"
+					       "User-Agent: %v\r\n"
+					       "%s";
+
+static const char *http_post_request_template = "POST %s HTTP/1.1\r\n"
+						"Host: %v\r\n"
+						"User-Agent: %v\r\n"
+						"Content-Length: %u\r\n"
+						"%s";
 
 static u32
 http_send_data (http_conn_t *hc, u8 *data, u32 length, u32 offset)
@@ -1134,9 +1140,11 @@ http_state_wait_app_method (http_conn_t *hc, transport_send_params_t *sp)
 {
   http_msg_t msg;
   session_t *as;
-  u8 *target = 0, *request;
+  u8 *target_buff = 0, *request = 0, *target;
   u32 offset;
   int rv;
+  http_sm_result_t sm_result = HTTP_SM_ERROR;
+  http_state_t next_state;
 
   as = session_get_from_handle (hc->h_pa_session_handle);
 
@@ -1155,47 +1163,107 @@ http_state_wait_app_method (http_conn_t *hc, transport_send_params_t *sp)
       goto error;
     }
 
-  /* currently we support only GET method */
-  if (msg.method_type != HTTP_REQ_GET)
+  /* read request target */
+  if (msg.data.type == HTTP_MSG_DATA_PTR)
     {
-      clib_warning ("unsupported method %d", msg.method_type);
-      goto error;
+      uword target_ptr;
+      rv = svm_fifo_dequeue (as->tx_fifo, sizeof (target_ptr),
+			     (u8 *) &target_ptr);
+      ASSERT (rv == sizeof (target_ptr));
+      target = uword_to_pointer (target_ptr, u8 *);
     }
-  if (msg.data.body_len != 0)
+  else
     {
-      clib_warning ("GET request shouldn't include data");
-      goto error;
+      vec_validate (target_buff, msg.data.target_path_len - 1);
+      rv =
+	svm_fifo_dequeue (as->tx_fifo, msg.data.target_path_len, target_buff);
+      ASSERT (rv == msg.data.target_path_len);
+      target = target_buff;
     }
 
-  /* read request target */
-  vec_validate (target, msg.data.target_path_len - 1);
-  rv = svm_fifo_dequeue (as->tx_fifo, msg.data.target_path_len, target);
-  ASSERT (rv == msg.data.target_path_len);
-
-  /*
-   * Add "protocol layer" headers:
-   * - host
-   * - user agent
-   */
-  request = format (0, http_request_template,
-		    /* target */
-		    target,
-		    /* Host */
-		    hc->host,
-		    /* User-Agent*/
-		    hc->app_name,
-		    /* Any headers from app? */
-		    msg.data.headers_len ? "" : "\r\n");
+  /* currently we support only GET and POST method */
+  if (msg.method_type == HTTP_REQ_GET)
+    {
+      if (msg.data.body_len)
+	{
+	  clib_warning ("GET request shouldn't include data");
+	  goto error;
+	}
+      /*
+       * Add "protocol layer" headers:
+       * - host
+       * - user agent
+       */
+      request = format (0, http_get_request_template,
+			/* target */
+			target,
+			/* Host */
+			hc->host,
+			/* User-Agent */
+			hc->app_name,
+			/* Any headers from app? */
+			msg.data.headers_len ? "" : "\r\n");
+
+      next_state = HTTP_STATE_WAIT_SERVER_REPLY;
+      sm_result = HTTP_SM_STOP;
+    }
+  else if (msg.method_type == HTTP_REQ_POST)
+    {
+      if (!msg.data.body_len)
+	{
+	  clib_warning ("POST request should include data");
+	  goto error;
+	}
+      /*
+       * Add "protocol layer" headers:
+       * - host
+       * - user agent
+       * - content length
+       */
+      request = format (0, http_post_request_template,
+			/* target */
+			target,
+			/* Host */
+			hc->host,
+			/* User-Agent */
+			hc->app_name,
+			/* Content-Length */
+			msg.data.body_len,
+			/* Any headers from app? */
+			msg.data.headers_len ? "" : "\r\n");
+
+      http_buffer_init (&hc->tx_buf, msg_to_buf_type[msg.data.type],
+			as->tx_fifo, msg.data.body_len);
+
+      next_state = HTTP_STATE_APP_IO_MORE_DATA;
+      sm_result = HTTP_SM_CONTINUE;
+    }
+  else
+    {
+      clib_warning ("unsupported method %d", msg.method_type);
+      goto error;
+    }
 
   /* Add headers from app (if any) */
   if (msg.data.headers_len)
     {
-      HTTP_DBG (0, "get headers from app, len %d", msg.data.headers_len);
-      u32 orig_len = vec_len (request);
-      vec_resize (request, msg.data.headers_len);
-      u8 *p = request + orig_len;
-      rv = svm_fifo_dequeue (as->tx_fifo, msg.data.headers_len, p);
-      ASSERT (rv == msg.data.headers_len);
+      HTTP_DBG (0, "got headers from app, len %d", msg.data.headers_len);
+      if (msg.data.type == HTTP_MSG_DATA_PTR)
+	{
+	  uword app_headers_ptr;
+	  rv = svm_fifo_dequeue (as->tx_fifo, sizeof (app_headers_ptr),
+				 (u8 *) &app_headers_ptr);
+	  ASSERT (rv == sizeof (app_headers_ptr));
+	  vec_append (request, uword_to_pointer (app_headers_ptr, u8 *));
+	}
+      else
+	{
+	  u32 orig_len = vec_len (request);
+	  vec_resize (request, msg.data.headers_len);
+	  u8 *p = request + orig_len;
+	  rv = svm_fifo_dequeue (as->tx_fifo, msg.data.headers_len, p);
+	  ASSERT (rv == msg.data.headers_len);
+	}
     }
   HTTP_DBG (0, "%v", request);
 
@@ -1203,22 +1271,23 @@ http_state_wait_app_method (http_conn_t *hc, transport_send_params_t *sp)
   if (offset != vec_len (request))
     {
       clib_warning ("sending request failed!");
+      sm_result = HTTP_SM_ERROR;
       goto error;
     }
 
-  http_state_change (hc, HTTP_STATE_WAIT_SERVER_REPLY);
-
-  vec_free (target);
-  vec_free (request);
-
-  return HTTP_SM_STOP;
+  http_state_change (hc, next_state);
+  goto done;
 
 error:
   svm_fifo_dequeue_drop_all (as->tx_fifo);
   session_transport_closing_notify (&hc->connection);
   session_transport_closed_notify (&hc->connection);
   http_disconnect_transport (hc);
-  return HTTP_SM_ERROR;
+
+done:
+  vec_free (target_buff);
+  vec_free (request);
+  return sm_result;
 }
 
 static http_sm_result_t
@@ -1334,8 +1403,11 @@ http_state_app_io_more_data (http_conn_t *hc, transport_send_params_t *sp)
       if (sent && svm_fifo_set_event (ts->tx_fifo))
 	session_program_tx_io_evt (ts->handle, SESSION_IO_EVT_TX_FLUSH);
 
-      /* Finished transaction, back to HTTP_STATE_WAIT_METHOD */
-      http_state_change (hc, HTTP_STATE_WAIT_CLIENT_METHOD);
+      /* Finished transaction:
+       * server back to HTTP_STATE_WAIT_METHOD
+       * client to HTTP_STATE_WAIT_SERVER_REPLY */
+      http_state_change (hc, hc->is_server ? HTTP_STATE_WAIT_CLIENT_METHOD :
+						   HTTP_STATE_WAIT_SERVER_REPLY);
       http_buffer_free (&hc->tx_buf);
     }
 
diff --git a/src/plugins/http/http.h b/src/plugins/http/http.h
index e3267dfc3b2..63d05860099 100644
--- a/src/plugins/http/http.h
+++ b/src/plugins/http/http.h
@@ -132,6 +132,8 @@ typedef enum http_target_form_
   _ (APP_XSLX, ".xlsx",                                                       \
      "application / vnd.openxmlformats - officedocument.spreadsheetml.sheet") \
   _ (APP_XUL, ".xul", "application / vnd.mozilla.xul + xml")                  \
+  _ (APP_X_WWW_FORM_URLENCODED, ".invalid",                                   \
+     "application / x-www-form-urlencoded")                                   \
   _ (APP_ZIP, ".zip", "application / zip")                                    \
   _ (AUDIO_AAC, ".aac", "audio / aac")                                        \
   _ (AUDIO_CD, ".cda", "application / x - cdf")                               \
diff --git a/src/plugins/http/http_buffer.c b/src/plugins/http/http_buffer.c
index f3dc308dbf8..bc1b8c08630 100644
--- a/src/plugins/http/http_buffer.c
+++ b/src/plugins/http/http_buffer.c
@@ -173,7 +173,7 @@ buf_ptr_drain (http_buffer_t *hb, u32 len)
   bf->segs[1].data += len;
   bf->segs[0].len -= len;
 
-  HTTP_DBG (1, "drained %u left %u", len, bf->segs[1].len);
+  HTTP_DBG (1, "drained %u left %u", len, bf->segs[0].len);
 
   if (!bf->segs[0].len)
     {
diff --git a/src/plugins/http/http_plugin.rst b/src/plugins/http/http_plugin.rst
index 273812735f7..4daef79b9cf 100644
--- a/src/plugins/http/http_plugin.rst
+++ b/src/plugins/http/http_plugin.rst
@@ -9,14 +9,14 @@ Overview
 --------
 
 This plugin adds the HTTP protocol to VPP's Host Stack.
-As a result parsing of HTTP/1 request or response is available for internal VPP applications.
+As a result parsing and serializing of HTTP/1 requests or responses are available for internal VPP applications.
 
 Usage
 -----
 
 The plugin exposes following inline functions: ``http_validate_abs_path_syntax``, ``http_validate_query_syntax``,
 ``http_percent_decode``, ``http_path_remove_dot_segments``, ``http_parse_headers``, ``http_get_header``,
-``http_free_header_table``.
+``http_free_header_table``, ``http_add_header``, ``http_serialize_headers``.
 
 It relies on the hoststack constructs and uses ``http_msg_data_t`` data structure for passing metadata to/from applications.
 
@@ -238,12 +238,18 @@ Finally application sends response body:
   if (svm_fifo_set_event (ts->tx_fifo))
     session_program_tx_io_evt (ts->handle, SESSION_IO_EVT_TX);
 
-Example above shows how to send body data by copy, alternatively you could pass it as pointer:
+Examples above shows how to send body and headers by copy, alternatively you could pass them as pointer:
 
 .. code-block:: C
 
   msg.data.type = HTTP_MSG_DATA_PTR;
   /* code omitted for brevity */
+  if (msg.data.headers_len)
+    {
+      uword headers = pointer_to_uword (headers_buf);
+      rv = svm_fifo_enqueue (ts->tx_fifo, sizeof (headers), (u8 *) &headers);
+      ASSERT (rv == sizeof (headers));
+    }
   uword data = pointer_to_uword (tx_buf);
   rv = svm_fifo_enqueue (ts->tx_fifo, sizeof (data), (u8 *) &data);
   ASSERT (rv == sizeof (data));
@@ -332,6 +338,28 @@ Finally application sends everything to HTTP layer:
   if (svm_fifo_set_event (as->tx_fifo))
     session_program_tx_io_evt (as->handle, SESSION_IO_EVT_TX);
 
+Examples above shows how to send buffers by copy, alternatively you could pass them as pointer:
+
+.. code-block:: C
+
+  msg.data.type = HTTP_MSG_DATA_PTR;
+  msg.method_type = HTTP_REQ_POST;
+  msg.data.body_len = vec_len (data);
+  /* code omitted for brevity */
+  uword target = pointer_to_uword (target);
+  uword headers = pointer_to_uword (headers_buf);
+  uword body = pointer_to_uword (data);
+  svm_fifo_seg_t segs[4] = {
+    { (u8 *) &msg, sizeof (msg) },
+    { (u8 *) &target, sizeof (target) },
+    { (u8 *) &headers, sizeof (headers) },
+    { (u8 *) &body, sizeof (body) },
+  };
+  rv = svm_fifo_enqueue_segments (s->tx_fifo, segs, 4, 0 /* allow partial */);
+  ASSERT (rv == (sizeof (msg) + sizeof (target) + sizeof (headers) + sizeof (body)));
+
+In this case you need to free data when you receive response or when session is closed.
+
 Receiving data
 """"""""""""""