Merge branch 'simple-extensions'

doc/Makefile.am

@@ -58,6 +58,7 @@ APIDOCS= \
 	nghttp2_option_set_no_http_messaging.rst \
 	nghttp2_option_set_no_recv_client_magic.rst \
 	nghttp2_option_set_peer_max_concurrent_streams.rst \
+	nghttp2_option_set_user_recv_extension_type.rst \
 	nghttp2_pack_settings_payload.rst \
 	nghttp2_priority_spec_check_default.rst \
 	nghttp2_priority_spec_default_init.rst \
@@ -70,16 +71,19 @@ APIDOCS= \
 	nghttp2_session_callbacks_set_on_begin_frame_callback.rst \
 	nghttp2_session_callbacks_set_on_begin_headers_callback.rst \
 	nghttp2_session_callbacks_set_on_data_chunk_recv_callback.rst \
+	nghttp2_session_callbacks_set_on_extension_chunk_recv_callback.rst \
 	nghttp2_session_callbacks_set_on_frame_not_send_callback.rst \
 	nghttp2_session_callbacks_set_on_frame_recv_callback.rst \
 	nghttp2_session_callbacks_set_on_frame_send_callback.rst \
 	nghttp2_session_callbacks_set_on_header_callback.rst \
 	nghttp2_session_callbacks_set_on_invalid_frame_recv_callback.rst \
 	nghttp2_session_callbacks_set_on_stream_close_callback.rst \
+	nghttp2_session_callbacks_set_pack_extension_callback.rst \
 	nghttp2_session_callbacks_set_recv_callback.rst \
 	nghttp2_session_callbacks_set_select_padding_callback.rst \
 	nghttp2_session_callbacks_set_send_callback.rst \
 	nghttp2_session_callbacks_set_send_data_callback.rst \
+	nghttp2_session_callbacks_set_unpack_extension_callback.rst \
 	nghttp2_session_client_new.rst \
 	nghttp2_session_client_new2.rst \
 	nghttp2_session_client_new3.rst \
@@ -131,6 +135,7 @@ APIDOCS= \
 	nghttp2_stream_get_weight.rst \
 	nghttp2_strerror.rst \
 	nghttp2_submit_data.rst \
+	nghttp2_submit_extension.rst \
 	nghttp2_submit_goaway.rst \
 	nghttp2_submit_headers.rst \
 	nghttp2_submit_ping.rst \

lib/includes/nghttp2/nghttp2.h

@@ -382,6 +382,10 @@ typedef enum {
    * Unexpected internal error, but recovered.
    */
   NGHTTP2_ERR_INTERNAL = -534,
+  /**
+   * Indicates that a processing was canceled.
+   */
+  NGHTTP2_ERR_CANCEL = -535,
   /**
    * The errors < :enum:`NGHTTP2_ERR_FATAL` mean that the library is
    * under unexpected condition and processing was terminated (e.g.,
@@ -1700,6 +1704,99 @@ typedef int (*nghttp2_on_begin_frame_callback)(nghttp2_session *session,
                                                const nghttp2_frame_hd *hd,
                                                void *user_data);
 
+/**
+ * @functypedef
+ *
+ * Callback function invoked when chunk of extension frame payload is
+ * received.  The |hd| points to frame header.  The received
+ * chunk is |data| of length |len|.
+ *
+ * The implementation of this function must return 0 if it succeeds.
+ *
+ * To abort processing this extension frame, return
+ * :enum:`NGHTTP2_ERR_CANCEL`.
+ *
+ * If fatal error occurred, application should return
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
+ * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the
+ * other values are returned, currently they are treated as
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp2_on_extension_chunk_recv_callback)(
+    nghttp2_session *session, const nghttp2_frame_hd *hd, const uint8_t *data,
+    size_t len, void *user_data);
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when library asks the application to
+ * unpack extension payload from its wire format.  The extension
+ * payload has been passed to the application using
+ * :type:`nghttp2_on_extension_chunk_recv_callback`.  The frame header
+ * is already unpacked by the library and provided as |hd|.
+ *
+ * To receive extension frames, the application must tell desired
+ * extension frame type to the library using
+ * `nghttp2_option_set_user_recv_extension_type()`.
+ *
+ * The implementation of this function may store the pointer to the
+ * created object as a result of unpacking in |*payload|, and returns
+ * 0.  The pointer stored in |*payload| is opaque to the library, and
+ * the library does not own its pointer.  |*payload| is initialized as
+ * ``NULL``.  The |*payload| is available as ``frame->ext.payload`` in
+ * :type:`nghttp2_on_frame_recv_callback`.  Therefore if application
+ * can free that memory inside :type:`nghttp2_on_frame_recv_callback`
+ * callback.  Of course, application has a liberty not ot use
+ * |*payload|, and do its own mechanism to process extension frames.
+ *
+ * To abort processing this extension frame, return
+ * :enum:`NGHTTP2_ERR_CANCEL`.
+ *
+ * If fatal error occurred, application should return
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
+ * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the
+ * other values are returned, currently they are treated as
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ */
+typedef int (*nghttp2_unpack_extension_callback)(nghttp2_session *session,
+                                                 void **payload,
+                                                 const nghttp2_frame_hd *hd,
+                                                 void *user_data);
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when library asks the application to pack
+ * extension payload in its wire format.  The frame header will be
+ * packed by library.  Application must pack payload only.
+ * ``frame->ext.payload`` is the object passed to
+ * `nghttp2_submit_extension()` as payload parameter.  Application
+ * must pack extension payload to the |buf| of its capacity |len|
+ * bytes.  The |len| is at least 16KiB.
+ *
+ * The implementation of this function should return the number of
+ * bytes written into |buf| when it succeeds.
+ *
+ * To abort processing this extension frame, return
+ * :enum:`NGHTTP2_ERR_CANCEL`, and
+ * :type:`nghttp2_on_frame_not_send_callback` will be invoked.
+ *
+ * If fatal error occurred, application should return
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
+ * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the
+ * other values are returned, currently they are treated as
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the return value is
+ * strictly larger than |len|, it is treated as
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ */
+typedef ssize_t (*nghttp2_pack_extension_callback)(nghttp2_session *session,
+                                                   uint8_t *buf, size_t len,
+                                                   const nghttp2_frame *frame,
+                                                   void *user_data);
+
 struct nghttp2_session_callbacks;
 
 /**
@@ -1892,6 +1989,37 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_send_data_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_send_data_callback send_data_callback);
 
+/**
+ * @function
+ *
+ * Sets callback function invoked when the library asks the
+ * application to pack extension frame payload in wire format.
+ */
+NGHTTP2_EXTERN void nghttp2_session_callbacks_set_pack_extension_callback(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_pack_extension_callback pack_extension_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when the library asks the
+ * application to unpack extension frame payload from wire format.
+ */
+NGHTTP2_EXTERN void nghttp2_session_callbacks_set_unpack_extension_callback(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_unpack_extension_callback unpack_extension_callback);
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when chunk of extension frame
+ * payload is received.
+ */
+NGHTTP2_EXTERN void
+nghttp2_session_callbacks_set_on_extension_chunk_recv_callback(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_on_extension_chunk_recv_callback on_extension_chunk_recv_callback);
+
 /**
  * @functypedef
  *
@@ -2106,6 +2234,23 @@ NGHTTP2_EXTERN void
 nghttp2_option_set_max_reserved_remote_streams(nghttp2_option *option,
                                                uint32_t val);
 
+/**
+ * @function
+ *
+ * Sets extension frame type the application is willing to handle with
+ * user defined callbacks (see
+ * :type:`nghttp2_on_extension_chunk_recv_callback` and
+ * :type:`nghttp2_unpack_extension_callback`).  The |type| is
+ * extension frame type, and must be strictly greater than 0x9.
+ * Otherwise, this function does nothing.  The application can call
+ * this function multiple times to set more than one frame type to
+ * receive.  The application does not have to call this function if it
+ * just sends extension frames.
+ */
+NGHTTP2_EXTERN void
+nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
+                                            uint8_t type);
+
 /**
  * @function
  *
@@ -3776,6 +3921,48 @@ NGHTTP2_EXTERN int nghttp2_submit_window_update(nghttp2_session *session,
                                                 int32_t stream_id,
                                                 int32_t window_size_increment);
 
+/**
+ * @function
+ *
+ * Submits extension frame.
+ *
+ * Application can pass arbitrary frame flags and stream ID in |flags|
+ * and |stream_id| respectively.  The |payload| is opaque pointer, and
+ * it can be accessible though ``frame->ext.payload`` in
+ * :type:`nghttp2_pack_extension_callback`.  The library will not own
+ * passed |payload| pointer.
+ *
+ * The application must set :type:`nghttp2_pack_extension_callback`
+ * using `nghttp2_session_callbacks_set_pack_extension_callback()`.
+ *
+ * The application should retain the memory pointed by |payload| until
+ * the transmission of extension frame is done (which is indicated by
+ * :type:`nghttp2_on_frame_send_callback`), or transmission fails
+ * (which is indicated by :type:`nghttp2_on_frame_not_send_callback`).
+ * If application does not touch this memory region after packing it
+ * into a wire format, application can free it inside
+ * :type:`nghttp2_pack_extension_callback`.
+ *
+ * The standard HTTP/2 frame cannot be sent with this function, so
+ * |type| must be strictly grater than 0x9.  Otherwise, this function
+ * will fail with error code :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :enum:`NGHTTP2_ERR_INVALID_STATE`
+ *     If :type:`nghttp2_pack_extension_callback` is not set.
+ * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
+ *     If  |type| specifies  standard  HTTP/2 frame  type.  The  frame
+ *     types  in the  rage [0x0,  0x9], both  inclusive, are  standard
+ *     HTTP/2 frame type, and cannot be sent using this function.
+ * :enum:`NGHTTP2_ERR_NOMEM`
+ *     Out of memory
+ */
+NGHTTP2_EXTERN int nghttp2_submit_extension(nghttp2_session *session,
+                                            uint8_t type, uint8_t flags,
+                                            int32_t stream_id, void *payload);
+
 /**
  * @function
  *

lib/nghttp2_callbacks.c

@@ -127,3 +127,21 @@ void nghttp2_session_callbacks_set_send_data_callback(
     nghttp2_send_data_callback send_data_callback) {
   cbs->send_data_callback = send_data_callback;
 }
+
+void nghttp2_session_callbacks_set_pack_extension_callback(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_pack_extension_callback pack_extension_callback) {
+  cbs->pack_extension_callback = pack_extension_callback;
+}
+
+void nghttp2_session_callbacks_set_unpack_extension_callback(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_unpack_extension_callback unpack_extension_callback) {
+  cbs->unpack_extension_callback = unpack_extension_callback;
+}
+
+void nghttp2_session_callbacks_set_on_extension_chunk_recv_callback(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_on_extension_chunk_recv_callback on_extension_chunk_recv_callback) {
+  cbs->on_extension_chunk_recv_callback = on_extension_chunk_recv_callback;
+}

lib/nghttp2_callbacks.h

@@ -107,6 +107,9 @@ struct nghttp2_session_callbacks {
    */
   nghttp2_on_begin_frame_callback on_begin_frame_callback;
   nghttp2_send_data_callback send_data_callback;
+  nghttp2_pack_extension_callback pack_extension_callback;
+  nghttp2_unpack_extension_callback unpack_extension_callback;
+  nghttp2_on_extension_chunk_recv_callback on_extension_chunk_recv_callback;
 };
 
 #endif /* NGHTTP2_CALLBACKS_H */

lib/nghttp2_frame.c

@@ -184,6 +184,17 @@ void nghttp2_frame_data_init(nghttp2_data *frame, uint8_t flags,
 
 void nghttp2_frame_data_free(nghttp2_data *frame _U_) {}
 
+void nghttp2_frame_extension_init(nghttp2_extension *frame, uint8_t type,
+                                  uint8_t flags, int32_t stream_id,
+                                  void *payload) {
+  nghttp2_frame_hd_init(&frame->hd, 0, type, flags, stream_id);
+  frame->payload = payload;
+}
+
+void nghttp2_frame_extension_free(nghttp2_extension *frame _U_) {
+  /* should be noop for performance reason */
+}
+
 size_t nghttp2_frame_priority_len(uint8_t flags) {
   if (flags & NGHTTP2_FLAG_PRIORITY) {
     return NGHTTP2_PRIORITY_SPECLEN;

lib/nghttp2_frame.h

@@ -439,6 +439,12 @@ void nghttp2_frame_window_update_init(nghttp2_window_update *frame,
 
 void nghttp2_frame_window_update_free(nghttp2_window_update *frame);
 
+void nghttp2_frame_extension_init(nghttp2_extension *frame, uint8_t type,
+                                  uint8_t flags, int32_t stream_id,
+                                  void *payload);
+
+void nghttp2_frame_extension_free(nghttp2_extension *frame);
+
 /*
  * Returns the number of padding bytes after payload.  The total
  * padding length is given in the |padlen|.  The returned value does

lib/nghttp2_helper.c

@@ -288,6 +288,8 @@ const char *nghttp2_strerror(int error_code) {
     return "Stream was refused";
   case NGHTTP2_ERR_INTERNAL:
     return "Internal error";
+  case NGHTTP2_ERR_CANCEL:
+    return "Cancel";
   case NGHTTP2_ERR_NOMEM:
     return "Out of memory";
   case NGHTTP2_ERR_CALLBACK_FAILURE:

lib/nghttp2_option.c

@@ -62,3 +62,14 @@ void nghttp2_option_set_max_reserved_remote_streams(nghttp2_option *option,
   option->opt_set_mask |= NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS;
   option->max_reserved_remote_streams = val;
 }
+
+void nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
+                                                 uint8_t type) {
+  if (type < 10) {
+    return;
+  }
+
+  option->opt_set_mask |= NGHTTP2_OPT_USER_RECV_EXT_TYPES;
+  option->user_recv_ext_types[type / 8] =
+      (uint8_t)(option->user_recv_ext_types[type / 8] | (1 << (type & 0x7)));
+}

lib/nghttp2_option.h

@@ -59,7 +59,8 @@ typedef enum {
   NGHTTP2_OPT_PEER_MAX_CONCURRENT_STREAMS = 1 << 1,
   NGHTTP2_OPT_NO_RECV_CLIENT_MAGIC = 1 << 2,
   NGHTTP2_OPT_NO_HTTP_MESSAGING = 1 << 3,
-  NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS = 1 << 4
+  NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS = 1 << 4,
+  NGHTTP2_OPT_USER_RECV_EXT_TYPES = 1 << 5
 } nghttp2_option_flag;
 
 /**
@@ -91,6 +92,10 @@ struct nghttp2_option {
    * NGHTTP2_OPT_NO_HTTP_MESSAGING
    */
   int no_http_messaging;
+  /**
+   * NGHTTP2_OPT_USER_RECV_EXT_TYPES
+   */
+  uint8_t user_recv_ext_types[32];
 };
 
 #endif /* NGHTTP2_OPTION_H */

lib/nghttp2_outbound_item.c

@@ -72,6 +72,9 @@ void nghttp2_outbound_item_free(nghttp2_outbound_item *item, nghttp2_mem *mem) {
   case NGHTTP2_WINDOW_UPDATE:
     nghttp2_frame_window_update_free(&frame->window_update);
     break;
+  default:
+    nghttp2_frame_extension_free(&frame->ext);
+    break;
   }
 }
 

lib/nghttp2_session.c

@@ -405,6 +405,11 @@ static int session_new(nghttp2_session **session_ptr,
 
       (*session_ptr)->opt_flags |= NGHTTP2_OPTMASK_NO_HTTP_MESSAGING;
     }
+
+    if (option->opt_set_mask & NGHTTP2_OPT_USER_RECV_EXT_TYPES) {
+      memcpy((*session_ptr)->user_recv_ext_types, option->user_recv_ext_types,
+             sizeof((*session_ptr)->user_recv_ext_types));
+    }
   }
 
   (*session_ptr)->callbacks = *callbacks;
@@ -1749,6 +1754,41 @@ static size_t session_estimate_headers_payload(nghttp2_session *session,
          additional;
 }
 
+static int session_pack_extension(nghttp2_session *session, nghttp2_bufs *bufs,
+                                  nghttp2_frame *frame) {
+  ssize_t rv;
+  nghttp2_buf *buf;
+  size_t buflen;
+  size_t framelen;
+
+  assert(session->callbacks.pack_extension_callback);
+
+  buf = &bufs->head->buf;
+  buflen = nghttp2_min(nghttp2_buf_avail(buf), NGHTTP2_MAX_PAYLOADLEN);
+
+  rv = session->callbacks.pack_extension_callback(session, buf->last, buflen,
+                                                  frame, session->user_data);
+  if (rv == NGHTTP2_ERR_CANCEL) {
+    return (int)rv;
+  }
+
+  if (rv < 0 || (size_t)rv > buflen) {
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  }
+
+  framelen = (size_t)rv;
+
+  frame->hd.length = framelen;
+
+  assert(buf->pos == buf->last);
+  buf->last += framelen;
+  buf->pos -= NGHTTP2_FRAME_HDLEN;
+
+  nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
+
+  return 0;
+}
+
 /*
  * This function serializes frame for transmission.
  *
@@ -1989,8 +2029,22 @@ static int session_prep_frame(nghttp2_session *session,
       nghttp2_frame_pack_window_update(&session->aob.framebufs,
                                        &frame->window_update);
       break;
+    case NGHTTP2_CONTINUATION:
+      /* We never handle CONTINUATION here. */
+      assert(0);
+      break;
     default:
-      return NGHTTP2_ERR_INVALID_ARGUMENT;
+      /* extension frame */
+      if (session_is_closing(session)) {
+        return NGHTTP2_ERR_SESSION_CLOSING;
+      }
+
+      rv = session_pack_extension(session, &session->aob.framebufs, frame);
+      if (rv != 0) {
+        return rv;
+      }
+
+      break;
     }
     return 0;
   } else {
@@ -3074,6 +3128,47 @@ static int session_call_on_header(nghttp2_session *session,
   return 0;
 }
 
+static int
+session_call_on_extension_chunk_recv_callback(nghttp2_session *session,
+                                              const uint8_t *data, size_t len) {
+  int rv;
+  nghttp2_inbound_frame *iframe = &session->iframe;
+  nghttp2_frame *frame = &iframe->frame;
+
+  if (session->callbacks.on_extension_chunk_recv_callback) {
+    rv = session->callbacks.on_extension_chunk_recv_callback(
+        session, &frame->hd, data, len, session->user_data);
+    if (rv == NGHTTP2_ERR_CANCEL) {
+      return rv;
+    }
+    if (rv != 0) {
+      return NGHTTP2_ERR_CALLBACK_FAILURE;
+    }
+  }
+
+  return 0;
+}
+
+static int session_call_unpack_extension_callback(nghttp2_session *session) {
+  int rv;
+  nghttp2_inbound_frame *iframe = &session->iframe;
+  nghttp2_frame *frame = &iframe->frame;
+  void *payload = NULL;
+
+  rv = session->callbacks.unpack_extension_callback(
+      session, &payload, &frame->hd, session->user_data);
+  if (rv == NGHTTP2_ERR_CANCEL) {
+    return rv;
+  }
+  if (rv != 0) {
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
+  }
+
+  frame->ext.payload = payload;
+
+  return 0;
+}
+
 /*
  * Handles frame size error.
  *
@@ -4412,6 +4507,24 @@ static int session_process_window_update_frame(nghttp2_session *session) {
   return nghttp2_session_on_window_update_received(session, frame);
 }
 
+static int session_process_extension_frame(nghttp2_session *session) {
+  int rv;
+  nghttp2_inbound_frame *iframe = &session->iframe;
+  nghttp2_frame *frame = &iframe->frame;
+
+  rv = session_call_unpack_extension_callback(session);
+  if (nghttp2_is_fatal(rv)) {
+    return rv;
+  }
+
+  /* This handles the case where rv == NGHTTP2_ERR_CANCEL as well */
+  if (rv != 0) {
+    return 0;
+  }
+
+  return session_call_on_frame_received(session, frame);
+}
+
 int nghttp2_session_on_data_received(nghttp2_session *session,
                                      nghttp2_frame *frame) {
   int rv = 0;
@@ -5230,11 +5343,21 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       default:
         DEBUGF(fprintf(stderr, "recv: unknown frame\n"));
 
-        /* Silently ignore unknown frame type. */
+        if (!session->callbacks.unpack_extension_callback ||
+            (session->user_recv_ext_types[iframe->frame.hd.type / 8] &
+             (1 << (iframe->frame.hd.type & 0x7))) == 0) {
+          /* Silently ignore unknown frame type. */
+
+          busy = 1;
+
+          iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+
+          break;
+        }
 
         busy = 1;
 
-        iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+        iframe->state = NGHTTP2_IB_READ_EXTENSION_PAYLOAD;
 
         break;
       }
@@ -5934,6 +6057,44 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       break;
     case NGHTTP2_IB_IGN_ALL:
       return (ssize_t)inlen;
+    case NGHTTP2_IB_READ_EXTENSION_PAYLOAD:
+      DEBUGF(fprintf(stderr, "recv: [IB_READ_EXTENSION_PAYLOAD]\n"));
+
+      readlen = inbound_frame_payload_readlen(iframe, in, last);
+      iframe->payloadleft -= readlen;
+      in += readlen;
+
+      DEBUGF(fprintf(stderr, "recv: readlen=%zu, payloadleft=%zu\n", readlen,
+                     iframe->payloadleft));
+
+      if (readlen > 0) {
+        rv = session_call_on_extension_chunk_recv_callback(
+            session, in - readlen, readlen);
+        if (nghttp2_is_fatal(rv)) {
+          return rv;
+        }
+
+        if (rv != 0) {
+          busy = 1;
+
+          iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+
+          break;
+        }
+      }
+
+      if (iframe->payloadleft > 0) {
+        break;
+      }
+
+      rv = session_process_extension_frame(session);
+      if (nghttp2_is_fatal(rv)) {
+        return rv;
+      }
+
+      session_inbound_frame_reset(session);
+
+      break;
     }
 
     if (!busy && in == last) {

lib/nghttp2_session.h

@@ -105,7 +105,8 @@ typedef enum {
   NGHTTP2_IB_READ_PAD_DATA,
   NGHTTP2_IB_READ_DATA,
   NGHTTP2_IB_IGN_DATA,
-  NGHTTP2_IB_IGN_ALL
+  NGHTTP2_IB_IGN_ALL,
+  NGHTTP2_IB_READ_EXTENSION_PAYLOAD
 } nghttp2_inbound_state;
 
 #define NGHTTP2_INBOUND_NUM_IV 7
@@ -304,6 +305,13 @@ struct nghttp2_session {
      this session.  The nonzero does not necessarily mean
      WINDOW_UPDATE is not queued. */
   uint8_t window_update_queued;
+  /* Bitfield of extension frame types that application is willing to
+     receive.  To designate the bit of given frame type i, use
+     user_recv_ext_types[i / 8] & (1 << (i & 0x7)).  First 10 frame
+     types are standard frame types and not used in this bitfield.  If
+     bit is set, it indicates that incoming frame with that type is
+     passed to user defined callbacks, otherwise they are ignored. */
+  uint8_t user_recv_ext_types[32];
 };
 
 /* Struct used when updating initial window size of each active

lib/nghttp2_submit.c

@@ -530,3 +530,40 @@ ssize_t nghttp2_pack_settings_payload(uint8_t *buf, size_t buflen,
 
   return (ssize_t)nghttp2_frame_pack_settings_payload(buf, iv, niv);
 }
+
+int nghttp2_submit_extension(nghttp2_session *session, uint8_t type,
+                             uint8_t flags, int32_t stream_id, void *payload) {
+  int rv;
+  nghttp2_outbound_item *item;
+  nghttp2_frame *frame;
+  nghttp2_mem *mem;
+
+  mem = &session->mem;
+
+  if (type <= NGHTTP2_CONTINUATION) {
+    return NGHTTP2_ERR_INVALID_ARGUMENT;
+  }
+
+  if (!session->callbacks.pack_extension_callback) {
+    return NGHTTP2_ERR_INVALID_STATE;
+  }
+
+  item = nghttp2_mem_malloc(mem, sizeof(nghttp2_outbound_item));
+  if (item == NULL) {
+    return NGHTTP2_ERR_NOMEM;
+  }
+
+  nghttp2_outbound_item_init(item);
+
+  frame = &item->frame;
+  nghttp2_frame_extension_init(&frame->ext, type, flags, stream_id, payload);
+
+  rv = nghttp2_session_add_item(session, item);
+  if (rv != 0) {
+    nghttp2_frame_extension_free(&frame->ext);
+    nghttp2_mem_free(mem, item);
+    return rv;
+  }
+
+  return 0;
+}

src/app_helper.cc

@@ -121,7 +121,7 @@ const char *strsettingsid(int32_t id) {
 } // namespace
 
 namespace {
-const char *strframetype(uint8_t type) {
+std::string strframetype(uint8_t type) {
   switch (type) {
   case NGHTTP2_DATA:
     return "DATA";
@@ -141,9 +141,13 @@ const char *strframetype(uint8_t type) {
     return "GOAWAY";
   case NGHTTP2_WINDOW_UPDATE:
     return "WINDOW_UPDATE";
-  default:
-    return "UNKNOWN";
   }
+
+  std::string s = "UNKNOWN(0x";
+  s += util::format_hex(&type, 1);
+  s += ")";
+
+  return s;
 };
 } // namespace
 
@@ -280,7 +284,7 @@ const char *frame_name_ansi_esc(print_type ptype) {
 namespace {
 void print_frame(print_type ptype, const nghttp2_frame *frame) {
   fprintf(outfile, "%s%s%s frame ", frame_name_ansi_esc(ptype),
-          strframetype(frame->hd.type), ansi_escend());
+          strframetype(frame->hd.type).c_str(), ansi_escend());
   print_frame_hd(frame->hd);
   if (frame->hd.flags) {
     print_frame_attr_indent();

tests/main.c

@@ -101,6 +101,8 @@ int main(int argc _U_, char *argv[] _U_) {
                    test_nghttp2_session_recv_settings_header_table_size) ||
       !CU_add_test(pSuite, "session_recv_too_large_frame_length",
                    test_nghttp2_session_recv_too_large_frame_length) ||
+      !CU_add_test(pSuite, "session_recv_extension",
+                   test_nghttp2_session_recv_extension) ||
       !CU_add_test(pSuite, "session_continue", test_nghttp2_session_continue) ||
       !CU_add_test(pSuite, "session_add_frame",
                    test_nghttp2_session_add_frame) ||
@@ -194,6 +196,7 @@ int main(int argc _U_, char *argv[] _U_) {
                    test_nghttp2_submit_shutdown_notice) ||
       !CU_add_test(pSuite, "submit_invalid_nv",
                    test_nghttp2_submit_invalid_nv) ||
+      !CU_add_test(pSuite, "submit_extension", test_nghttp2_submit_extension) ||
       !CU_add_test(pSuite, "session_open_stream",
                    test_nghttp2_session_open_stream) ||
       !CU_add_test(pSuite, "session_open_stream_with_idle_stream_dep",

tests/nghttp2_session_test.c

@@ -54,6 +54,7 @@ typedef struct {
   scripted_data_feed *df;
   int frame_recv_cb_called, invalid_frame_recv_cb_called;
   uint8_t recv_frame_type;
+  nghttp2_frame_hd recv_frame_hd;
   int frame_send_cb_called;
   uint8_t sent_frame_type;
   int frame_not_send_cb_called;
@@ -73,6 +74,7 @@ typedef struct {
   size_t data_chunk_len;
   size_t padlen;
   int begin_frame_cb_called;
+  nghttp2_buf scratchbuf;
 } my_user_data;
 
 static const nghttp2_nv reqnv[] = {
@@ -175,6 +177,8 @@ static int on_frame_recv_callback(nghttp2_session *session _U_,
   my_user_data *ud = (my_user_data *)user_data;
   ++ud->frame_recv_cb_called;
   ud->recv_frame_type = frame->hd.type;
+  ud->recv_frame_hd = frame->hd;
+
   return 0;
 }
 
@@ -416,6 +420,54 @@ static int on_stream_close_callback(nghttp2_session *session _U_,
   return 0;
 }
 
+static ssize_t pack_extension_callback(nghttp2_session *session _U_,
+                                       uint8_t *buf, size_t len _U_,
+                                       const nghttp2_frame *frame,
+                                       void *user_data _U_) {
+  nghttp2_buf *p = frame->ext.payload;
+
+  memcpy(buf, p->pos, nghttp2_buf_len(p));
+
+  return (ssize_t)nghttp2_buf_len(p);
+}
+
+static int on_extension_chunk_recv_callback(nghttp2_session *session _U_,
+                                            const nghttp2_frame_hd *hd _U_,
+                                            const uint8_t *data, size_t len,
+                                            void *user_data) {
+  my_user_data *my_data = (my_user_data *)user_data;
+  nghttp2_buf *buf = &my_data->scratchbuf;
+
+  buf->last = nghttp2_cpymem(buf->last, data, len);
+
+  return 0;
+}
+
+static int cancel_on_extension_chunk_recv_callback(
+    nghttp2_session *session _U_, const nghttp2_frame_hd *hd _U_,
+    const uint8_t *data _U_, size_t len _U_, void *user_data _U_) {
+  return NGHTTP2_ERR_CANCEL;
+}
+
+static int unpack_extension_callback(nghttp2_session *session _U_,
+                                     void **payload,
+                                     const nghttp2_frame_hd *hd _U_,
+                                     void *user_data) {
+  my_user_data *my_data = (my_user_data *)user_data;
+  nghttp2_buf *buf = &my_data->scratchbuf;
+
+  *payload = buf;
+
+  return 0;
+}
+
+static int cancel_unpack_extension_callback(nghttp2_session *session _U_,
+                                            void **payload _U_,
+                                            const nghttp2_frame_hd *hd _U_,
+                                            void *user_data _U_) {
+  return NGHTTP2_ERR_CANCEL;
+}
+
 static nghttp2_settings_entry *dup_iv(const nghttp2_settings_entry *iv,
                                       size_t niv) {
   return nghttp2_frame_iv_copy(iv, niv, nghttp2_mem_default());
@@ -1822,6 +1874,87 @@ void test_nghttp2_session_recv_too_large_frame_length(void) {
   nghttp2_session_del(session);
 }
 
+void test_nghttp2_session_recv_extension(void) {
+  nghttp2_session *session;
+  nghttp2_session_callbacks callbacks;
+  my_user_data ud;
+  nghttp2_buf buf;
+  nghttp2_frame_hd hd;
+  nghttp2_mem *mem;
+  const char data[] = "Hello World!";
+  ssize_t rv;
+  nghttp2_option *option;
+
+  mem = nghttp2_mem_default();
+
+  memset(&callbacks, 0, sizeof(nghttp2_session_callbacks));
+
+  callbacks.on_extension_chunk_recv_callback = on_extension_chunk_recv_callback;
+  callbacks.unpack_extension_callback = unpack_extension_callback;
+  callbacks.on_frame_recv_callback = on_frame_recv_callback;
+
+  nghttp2_option_new(&option);
+  nghttp2_option_set_user_recv_extension_type(option, 111);
+
+  nghttp2_buf_init2(&ud.scratchbuf, 4096, mem);
+  nghttp2_buf_init2(&buf, 4096, mem);
+
+  nghttp2_frame_hd_init(&hd, sizeof(data), 111, 0xab, 1000000007);
+  nghttp2_frame_pack_frame_hd(buf.last, &hd);
+  buf.last += NGHTTP2_FRAME_HDLEN;
+  buf.last = nghttp2_cpymem(buf.last, data, sizeof(data));
+
+  nghttp2_session_client_new2(&session, &callbacks, &ud, option);
+
+  nghttp2_frame_hd_init(&ud.recv_frame_hd, 0, 0, 0, 0);
+  rv = nghttp2_session_mem_recv(session, buf.pos, nghttp2_buf_len(&buf));
+
+  CU_ASSERT(NGHTTP2_FRAME_HDLEN + hd.length == (size_t)rv);
+  CU_ASSERT(111 == ud.recv_frame_hd.type);
+  CU_ASSERT(0xab == ud.recv_frame_hd.flags);
+  CU_ASSERT(1000000007 == ud.recv_frame_hd.stream_id);
+  CU_ASSERT(0 == memcmp(data, ud.scratchbuf.pos, sizeof(data)));
+
+  nghttp2_session_del(session);
+
+  /* cancel in on_extension_chunk_recv_callback */
+  nghttp2_buf_reset(&ud.scratchbuf);
+
+  callbacks.on_extension_chunk_recv_callback =
+      cancel_on_extension_chunk_recv_callback;
+
+  nghttp2_session_server_new2(&session, &callbacks, &ud, option);
+
+  ud.frame_recv_cb_called = 0;
+  rv = nghttp2_session_mem_recv(session, buf.pos, nghttp2_buf_len(&buf));
+
+  CU_ASSERT(NGHTTP2_FRAME_HDLEN + hd.length == (size_t)rv);
+  CU_ASSERT(0 == ud.frame_recv_cb_called);
+
+  nghttp2_session_del(session);
+
+  /* cancel in unpack_extension_callback */
+  nghttp2_buf_reset(&ud.scratchbuf);
+
+  callbacks.on_extension_chunk_recv_callback = on_extension_chunk_recv_callback;
+  callbacks.unpack_extension_callback = cancel_unpack_extension_callback;
+
+  nghttp2_session_server_new2(&session, &callbacks, &ud, option);
+
+  ud.frame_recv_cb_called = 0;
+  rv = nghttp2_session_mem_recv(session, buf.pos, nghttp2_buf_len(&buf));
+
+  CU_ASSERT(NGHTTP2_FRAME_HDLEN + hd.length == (size_t)rv);
+  CU_ASSERT(0 == ud.frame_recv_cb_called);
+
+  nghttp2_session_del(session);
+
+  nghttp2_buf_free(&buf, mem);
+  nghttp2_buf_free(&ud.scratchbuf, mem);
+
+  nghttp2_option_del(option);
+}
+
 void test_nghttp2_session_continue(void) {
   nghttp2_session *session;
   nghttp2_session_callbacks callbacks;
@@ -5005,6 +5138,67 @@ void test_nghttp2_submit_invalid_nv(void) {
   nghttp2_session_del(session);
 }
 
+void test_nghttp2_submit_extension(void) {
+  nghttp2_session *session;
+  nghttp2_session_callbacks callbacks;
+  my_user_data ud;
+  accumulator acc;
+  nghttp2_mem *mem;
+  const char data[] = "Hello World!";
+  size_t len;
+  int32_t stream_id;
+  int rv;
+
+  mem = nghttp2_mem_default();
+
+  memset(&callbacks, 0, sizeof(nghttp2_session_callbacks));
+
+  callbacks.pack_extension_callback = pack_extension_callback;
+  callbacks.send_callback = accumulator_send_callback;
+
+  nghttp2_buf_init2(&ud.scratchbuf, 4096, mem);
+
+  nghttp2_session_client_new(&session, &callbacks, &ud);
+
+  ud.scratchbuf.last = nghttp2_cpymem(ud.scratchbuf.last, data, sizeof(data));
+  ud.acc = &acc;
+
+  rv = nghttp2_submit_extension(session, 211, 0x01, 3, &ud.scratchbuf);
+
+  CU_ASSERT(0 == rv);
+
+  acc.length = 0;
+
+  rv = nghttp2_session_send(session);
+
+  CU_ASSERT(0 == rv);
+  CU_ASSERT(NGHTTP2_FRAME_HDLEN + sizeof(data) == acc.length);
+
+  len = nghttp2_get_uint32(acc.buf) >> 8;
+
+  CU_ASSERT(sizeof(data) == len);
+  CU_ASSERT(211 == acc.buf[3]);
+  CU_ASSERT(0x01 == acc.buf[4]);
+
+  stream_id = (int32_t)nghttp2_get_uint32(acc.buf + 5);
+
+  CU_ASSERT(3 == stream_id);
+  CU_ASSERT(0 == memcmp(data, &acc.buf[NGHTTP2_FRAME_HDLEN], sizeof(data)));
+
+  nghttp2_session_del(session);
+
+  /* submitting standard HTTP/2 frame is error */
+  nghttp2_session_server_new(&session, &callbacks, &ud);
+
+  rv = nghttp2_submit_extension(session, NGHTTP2_GOAWAY, NGHTTP2_FLAG_NONE, 0,
+                                NULL);
+
+  CU_ASSERT(NGHTTP2_ERR_INVALID_ARGUMENT == rv);
+
+  nghttp2_session_del(session);
+  nghttp2_buf_free(&ud.scratchbuf, mem);
+}
+
 void test_nghttp2_session_open_stream(void) {
   nghttp2_session *session;
   nghttp2_session_callbacks callbacks;

tests/nghttp2_session_test.h

@@ -40,6 +40,7 @@ void test_nghttp2_session_recv_unknown_frame(void);
 void test_nghttp2_session_recv_unexpected_continuation(void);
 void test_nghttp2_session_recv_settings_header_table_size(void);
 void test_nghttp2_session_recv_too_large_frame_length(void);
+void test_nghttp2_session_recv_extension(void);
 void test_nghttp2_session_continue(void);
 void test_nghttp2_session_add_frame(void);
 void test_nghttp2_session_on_request_headers_received(void);
@@ -89,6 +90,7 @@ void test_nghttp2_submit_window_update(void);
 void test_nghttp2_submit_window_update_local_window_size(void);
 void test_nghttp2_submit_shutdown_notice(void);
 void test_nghttp2_submit_invalid_nv(void);
+void test_nghttp2_submit_extension(void);
 void test_nghttp2_session_open_stream(void);
 void test_nghttp2_session_open_stream_with_idle_stream_dep(void);
 void test_nghttp2_session_get_next_ob_item(void);