diff --git a/.travis.yml b/.travis.yml
index 59d8c3a2..78e69d34 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,31 +1,31 @@
 language: cpp
 compiler:
   - clang
-#Disable gcc build for the moment...
-#  - gcc
+  - gcc
+sudo: false
+addons:
+  apt:
+    sources:
+    - ubuntu-toolchain-r-test
+    packages:
+    - g++-4.9
+    - libstdc++-4.9-dev
+    - autoconf
+    - automake
+    - autotools-dev
+    - libtool
+    - pkg-config
+    - zlib1g-dev
+    - libcunit1-dev
+    - libssl-dev
+    - libxml2-dev
+    - libev-dev
+    - libevent-dev
+    - libjansson-dev
+    - libjemalloc-dev
 before_install:
   - $CC --version
-  - sudo add-apt-repository --yes ppa:ubuntu-toolchain-r/test
-  - sudo apt-get update -qq
-    #Install and use gcc-4.8 (don't build with gcc-4.6)
-    #libstdc++-4.8 is needed by Clang to build too
-  - sudo apt-get -qq install g++-4.8 libstdc++-4.8-dev
-  - >
-      sudo apt-get install --no-install-recommends -qq
-      autoconf
-      automake
-      autotools-dev
-      libtool
-      pkg-config
-      zlib1g-dev
-      libcunit1-dev
-      libssl-dev
-      libxml2-dev
-      libev-dev
-      libevent-dev
-      libjansson-dev
-      libjemalloc-dev
-  - if [ "$CXX" = "g++" ]; then export CXX="g++-4.8" CC="gcc-4.8"; fi
+  - if [ "$CXX" = "g++" ]; then export CXX="g++-4.9" CC="gcc-4.9"; fi
   - $CC --version
 before_script:
   - autoreconf -i
diff --git a/examples/tiny-nghttpd.c b/examples/tiny-nghttpd.c
index c586adfb..5e53cb6e 100644
--- a/examples/tiny-nghttpd.c
+++ b/examples/tiny-nghttpd.c
@@ -697,7 +697,8 @@ static ssize_t fd_read_callback(nghttp2_session *session _U_,
                                 nghttp2_data_source *source,
                                 void *user_data _U_) {
   stream *strm = source->ptr;
-  ssize_t nread = (int64_t)length < strm->fileleft ? length : strm->fileleft;
+  ssize_t nread =
+      (int64_t)length < strm->fileleft ? (int64_t)length : strm->fileleft;
 
   *data_flags |= NGHTTP2_DATA_FLAG_NO_COPY;
 
diff --git a/lib/includes/nghttp2/nghttp2.h b/lib/includes/nghttp2/nghttp2.h
index 036cd54f..4d6ad0ef 100644
--- a/lib/includes/nghttp2/nghttp2.h
+++ b/lib/includes/nghttp2/nghttp2.h
@@ -226,8 +226,9 @@ typedef enum {
    */
   NGHTTP2_ERR_UNSUPPORTED_VERSION = -503,
   /**
-   * Used as a return value from :type:`nghttp2_send_callback` and
-   * :type:`nghttp2_recv_callback` to indicate that the operation
+   * Used as a return value from :type:`nghttp2_send_callback`,
+   * :type:`nghttp2_recv_callback` and
+   * :type:`nghttp2_send_data_callback` to indicate that the operation
    * would block.
    */
   NGHTTP2_ERR_WOULDBLOCK = -504,
@@ -1217,10 +1218,10 @@ typedef ssize_t (*nghttp2_recv_callback)(nghttp2_session *session, uint8_t *buf,
 /**
  * @functypedef
  *
- * Callback function invoked by `nghttp2_session_recv()` when a frame
- * is received.  The |user_data| pointer is the third argument passed
- * in to the call to `nghttp2_session_client_new()` or
- * `nghttp2_session_server_new()`.
+ * Callback function invoked by `nghttp2_session_recv()` and
+ * `nghttp2_session_mem_recv()` when a frame is received.  The
+ * |user_data| pointer is the third argument passed in to the call to
+ * `nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
  *
  * If frame is HEADERS or PUSH_PROMISE, the ``nva`` and ``nvlen``
  * member of their data structure are always ``NULL`` and 0
@@ -1255,14 +1256,14 @@ typedef int (*nghttp2_on_frame_recv_callback)(nghttp2_session *session,
 /**
  * @functypedef
  *
- * Callback function invoked by `nghttp2_session_recv()` when an
- * invalid non-DATA frame is received.  The error is indicated by the
- * |lib_error_code|, which is one of the values defined in
- * :type:`nghttp2_error`.  When this callback function is invoked, the
- * library automatically submits either RST_STREAM or GOAWAY frame.
- * The |user_data| pointer is the third argument passed in to the call
- * to `nghttp2_session_client_new()` or
- * `nghttp2_session_server_new()`.
+ * Callback function invoked by `nghttp2_session_recv()` and
+ * `nghttp2_session_mem_recv()` when an invalid non-DATA frame is
+ * received.  The error is indicated by the |lib_error_code|, which is
+ * one of the values defined in :type:`nghttp2_error`.  When this
+ * callback function is invoked, the library automatically submits
+ * either RST_STREAM or GOAWAY frame.  The |user_data| pointer is the
+ * third argument passed in to the call to
+ * `nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
  *
  * If frame is HEADERS or PUSH_PROMISE, the ``nva`` and ``nvlen``
  * member of their data structure are always ``NULL`` and 0
@@ -1270,7 +1271,7 @@ typedef int (*nghttp2_on_frame_recv_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1303,7 +1304,7 @@ typedef int (*nghttp2_on_invalid_frame_recv_callback)(
  * region included in the input bytes.
  *
  * The implementation of this function must return 0 if it succeeds.
- * If nonzero is returned, it is treated as fatal error and
+ * If nonzero is returned, it is treated as fatal error, and
  * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
@@ -1326,7 +1327,7 @@ typedef int (*nghttp2_on_data_chunk_recv_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1345,7 +1346,7 @@ typedef int (*nghttp2_before_frame_send_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1367,7 +1368,7 @@ typedef int (*nghttp2_on_frame_send_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
  * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * `nghttp2_session_get_stream_user_data()` can be used to get
@@ -1397,8 +1398,9 @@ typedef int (*nghttp2_on_frame_not_send_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_send()` functions
- * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * `nghttp2_session_recv()`, `nghttp2_session_mem_recv()`,
+ * `nghttp2_session_send()`, and `nghttp2_session_mem_send()`
+ * functions immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_on_stream_close_callback()`.
@@ -1440,13 +1442,26 @@ typedef int (*nghttp2_on_stream_close_callback)(nghttp2_session *session,
  * frame with ``frame->headers.cat == NGHTTP2_HCAT_HEADERS``
  * containing final response headers (non-1xx status code).  The
  * trailer headers also has ``frame->headers.cat ==
- * NGHTTP2_HCAT_HEADERS`` which does not containg any status code.
+ * NGHTTP2_HCAT_HEADERS`` which does not contain any status code.
  *
- * The implementation of this function must return 0 if it succeeds or
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If nonzero value other than
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned, it is treated as
- * if :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned.  If
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
+ * Returning :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will close
+ * the stream (promised stream if frame is PUSH_PROMISE) by issuing
+ * RST_STREAM with :enum:`NGHTTP2_INTERNAL_ERROR`.  In this case,
+ * :type:`nghttp2_on_header_callback` and
+ * :type:`nghttp2_on_frame_recv_callback` will not be invoked.  If a
+ * different error code is desirable, use
+ * `nghttp2_submit_rst_stream()` with a desired error code and then
+ * return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  Again, use
+ * ``frame->push_promise.promised_stream_id`` as stream_id parameter
+ * in `nghttp2_submit_rst_stream()` if frame is PUSH_PROMISE.
+ *
+ * The implementation of this function must return 0 if it succeeds.
+ * It can return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` to
+ * reset the stream (promised stream if frame is PUSH_PROMISE).  For
+ * critical errors, it must return
+ * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other value is
+ * returned, it is treated as if :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`
+ * is returned.  If :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
  * `nghttp2_session_mem_recv()` function will immediately return
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
@@ -1501,12 +1516,15 @@ typedef int (*nghttp2_on_begin_headers_callback)(nghttp2_session *session,
  * included in the input bytes.
  *
  * Returning :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will close
- * the stream by issuing RST_STREAM with
- * :enum:`NGHTTP2_INTERNAL_ERROR`.  In this case,
+ * the stream (promised stream if frame is PUSH_PROMISE) by issuing
+ * RST_STREAM with :enum:`NGHTTP2_INTERNAL_ERROR`.  In this case,
+ * :type:`nghttp2_on_header_callback` and
  * :type:`nghttp2_on_frame_recv_callback` will not be invoked.  If a
  * different error code is desirable, use
  * `nghttp2_submit_rst_stream()` with a desired error code and then
- * return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
+ * return :enum:`NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.  Again, use
+ * ``frame->push_promise.promised_stream_id`` as stream_id parameter
+ * in `nghttp2_submit_rst_stream()` if frame is PUSH_PROMISE.
  *
  * The implementation of this function must return 0 if it succeeds.
  * It may return :enum:`NGHTTP2_ERR_PAUSE` or
@@ -1538,8 +1556,8 @@ typedef int (*nghttp2_on_header_callback)(nghttp2_session *session,
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.  Returning
  * ``frame->hd.length`` means no padding is added.  Returning
  * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE` will make
- * `nghttp2_session_send()` function immediately return
- * :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
+ * immediately return :enum:`NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
  * `nghttp2_session_callbacks_set_select_padding_callback()`.
@@ -1668,8 +1686,8 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_recv_callback(
 /**
  * @function
  *
- * Sets callback function invoked by `nghttp2_session_recv()` when a
- * frame is received.
+ * Sets callback function invoked by `nghttp2_session_recv()` and
+ * `nghttp2_session_mem_recv()` when a frame is received.
  */
 NGHTTP2_EXTERN void nghttp2_session_callbacks_set_on_frame_recv_callback(
     nghttp2_session_callbacks *cbs,
@@ -1678,8 +1696,9 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_on_frame_recv_callback(
 /**
  * @function
  *
- * Sets callback function invoked by `nghttp2_session_recv()` when an
- * invalid non-DATA frame is received.
+ * Sets callback function invoked by `nghttp2_session_recv()` and
+ * `nghttp2_session_mem_recv()` when an invalid non-DATA frame is
+ * received.
  */
 NGHTTP2_EXTERN void
 nghttp2_session_callbacks_set_on_invalid_frame_recv_callback(
diff --git a/lib/nghttp2_hd.c b/lib/nghttp2_hd.c
index b26fbbc3..3a97ac71 100644
--- a/lib/nghttp2_hd.c
+++ b/lib/nghttp2_hd.c
@@ -114,7 +114,7 @@ static int memeq(const void *s1, const void *s2, size_t n) {
  * This function was generated by genlibtokenlookup.py.  Inspired by
  * h2o header lookup.  https://github.com/h2o/h2o
  */
-static inline int lookup_token(const uint8_t *name, size_t namelen) {
+static int lookup_token(const uint8_t *name, size_t namelen) {
   switch (namelen) {
   case 2:
     switch (name[1]) {
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 2109eb4a..199b16fa 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -3098,6 +3098,9 @@ static int session_call_on_begin_headers(nghttp2_session *session,
   if (session->callbacks.on_begin_headers_callback) {
     rv = session->callbacks.on_begin_headers_callback(session, frame,
                                                       session->user_data);
+    if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
+      return rv;
+    }
     if (rv != 0) {
       return NGHTTP2_ERR_CALLBACK_FAILURE;
     }
@@ -5110,6 +5113,16 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
         busy = 1;
 
+        if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
+          rv = nghttp2_session_add_rst_stream(
+              session, iframe->frame.hd.stream_id, NGHTTP2_INTERNAL_ERROR);
+          if (nghttp2_is_fatal(rv)) {
+            return rv;
+          }
+          iframe->state = NGHTTP2_IB_IGN_HEADER_BLOCK;
+          break;
+        }
+
         if (rv == NGHTTP2_ERR_IGN_HEADER_BLOCK) {
           iframe->state = NGHTTP2_IB_IGN_HEADER_BLOCK;
           break;
@@ -5354,6 +5367,16 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
         busy = 1;
 
+        if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
+          rv = nghttp2_session_add_rst_stream(
+              session, iframe->frame.hd.stream_id, NGHTTP2_INTERNAL_ERROR);
+          if (nghttp2_is_fatal(rv)) {
+            return rv;
+          }
+          iframe->state = NGHTTP2_IB_IGN_HEADER_BLOCK;
+          break;
+        }
+
         if (rv == NGHTTP2_ERR_IGN_HEADER_BLOCK) {
           iframe->state = NGHTTP2_IB_IGN_HEADER_BLOCK;
           break;
@@ -5418,6 +5441,17 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
         busy = 1;
 
+        if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
+          rv = nghttp2_session_add_rst_stream(
+              session, iframe->frame.push_promise.promised_stream_id,
+              NGHTTP2_INTERNAL_ERROR);
+          if (nghttp2_is_fatal(rv)) {
+            return rv;
+          }
+          iframe->state = NGHTTP2_IB_IGN_HEADER_BLOCK;
+          break;
+        }
+
         if (rv == NGHTTP2_ERR_IGN_HEADER_BLOCK) {
           iframe->state = NGHTTP2_IB_IGN_HEADER_BLOCK;
           break;
@@ -5524,8 +5558,12 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           in += hd_proclen;
           iframe->payloadleft -= hd_proclen;
 
+          /* Use promised stream ID for PUSH_PROMISE */
           rv = nghttp2_session_add_rst_stream(
-              session, iframe->frame.hd.stream_id, NGHTTP2_INTERNAL_ERROR);
+              session, iframe->frame.hd.type == NGHTTP2_PUSH_PROMISE
+                           ? iframe->frame.push_promise.promised_stream_id
+                           : iframe->frame.hd.stream_id,
+              NGHTTP2_INTERNAL_ERROR);
           if (nghttp2_is_fatal(rv)) {
             return rv;
           }
diff --git a/mkhufftbl.py b/mkhufftbl.py
index c243abca..86960428 100755
--- a/mkhufftbl.py
+++ b/mkhufftbl.py
@@ -10,8 +10,271 @@
 from __future__ import unicode_literals
 import re
 import sys
+import StringIO
+
+# From [1]
+HUFFMAN_CODE_TABLE = """\
+    (  0)  |11111111|11000                             1ff8  [13]
+    (  1)  |11111111|11111111|1011000                7fffd8  [23]
+    (  2)  |11111111|11111111|11111110|0010         fffffe2  [28]
+    (  3)  |11111111|11111111|11111110|0011         fffffe3  [28]
+    (  4)  |11111111|11111111|11111110|0100         fffffe4  [28]
+    (  5)  |11111111|11111111|11111110|0101         fffffe5  [28]
+    (  6)  |11111111|11111111|11111110|0110         fffffe6  [28]
+    (  7)  |11111111|11111111|11111110|0111         fffffe7  [28]
+    (  8)  |11111111|11111111|11111110|1000         fffffe8  [28]
+    (  9)  |11111111|11111111|11101010               ffffea  [24]
+    ( 10)  |11111111|11111111|11111111|111100      3ffffffc  [30]
+    ( 11)  |11111111|11111111|11111110|1001         fffffe9  [28]
+    ( 12)  |11111111|11111111|11111110|1010         fffffea  [28]
+    ( 13)  |11111111|11111111|11111111|111101      3ffffffd  [30]
+    ( 14)  |11111111|11111111|11111110|1011         fffffeb  [28]
+    ( 15)  |11111111|11111111|11111110|1100         fffffec  [28]
+    ( 16)  |11111111|11111111|11111110|1101         fffffed  [28]
+    ( 17)  |11111111|11111111|11111110|1110         fffffee  [28]
+    ( 18)  |11111111|11111111|11111110|1111         fffffef  [28]
+    ( 19)  |11111111|11111111|11111111|0000         ffffff0  [28]
+    ( 20)  |11111111|11111111|11111111|0001         ffffff1  [28]
+    ( 21)  |11111111|11111111|11111111|0010         ffffff2  [28]
+    ( 22)  |11111111|11111111|11111111|111110      3ffffffe  [30]
+    ( 23)  |11111111|11111111|11111111|0011         ffffff3  [28]
+    ( 24)  |11111111|11111111|11111111|0100         ffffff4  [28]
+    ( 25)  |11111111|11111111|11111111|0101         ffffff5  [28]
+    ( 26)  |11111111|11111111|11111111|0110         ffffff6  [28]
+    ( 27)  |11111111|11111111|11111111|0111         ffffff7  [28]
+    ( 28)  |11111111|11111111|11111111|1000         ffffff8  [28]
+    ( 29)  |11111111|11111111|11111111|1001         ffffff9  [28]
+    ( 30)  |11111111|11111111|11111111|1010         ffffffa  [28]
+    ( 31)  |11111111|11111111|11111111|1011         ffffffb  [28]
+' ' ( 32)  |010100                                       14  [ 6]
+'!' ( 33)  |11111110|00                                 3f8  [10]
+'"' ( 34)  |11111110|01                                 3f9  [10]
+'#' ( 35)  |11111111|1010                               ffa  [12]
+'$' ( 36)  |11111111|11001                             1ff9  [13]
+'%' ( 37)  |010101                                       15  [ 6]
+'&' ( 38)  |11111000                                     f8  [ 8]
+''' ( 39)  |11111111|010                                7fa  [11]
+'(' ( 40)  |11111110|10                                 3fa  [10]
+')' ( 41)  |11111110|11                                 3fb  [10]
+'*' ( 42)  |11111001                                     f9  [ 8]
+'+' ( 43)  |11111111|011                                7fb  [11]
+',' ( 44)  |11111010                                     fa  [ 8]
+'-' ( 45)  |010110                                       16  [ 6]
+'.' ( 46)  |010111                                       17  [ 6]
+'/' ( 47)  |011000                                       18  [ 6]
+'0' ( 48)  |00000                                         0  [ 5]
+'1' ( 49)  |00001                                         1  [ 5]
+'2' ( 50)  |00010                                         2  [ 5]
+'3' ( 51)  |011001                                       19  [ 6]
+'4' ( 52)  |011010                                       1a  [ 6]
+'5' ( 53)  |011011                                       1b  [ 6]
+'6' ( 54)  |011100                                       1c  [ 6]
+'7' ( 55)  |011101                                       1d  [ 6]
+'8' ( 56)  |011110                                       1e  [ 6]
+'9' ( 57)  |011111                                       1f  [ 6]
+':' ( 58)  |1011100                                      5c  [ 7]
+';' ( 59)  |11111011                                     fb  [ 8]
+'<' ( 60)  |11111111|1111100                           7ffc  [15]
+'=' ( 61)  |100000                                       20  [ 6]
+'>' ( 62)  |11111111|1011                               ffb  [12]
+'?' ( 63)  |11111111|00                                 3fc  [10]
+'@' ( 64)  |11111111|11010                             1ffa  [13]
+'A' ( 65)  |100001                                       21  [ 6]
+'B' ( 66)  |1011101                                      5d  [ 7]
+'C' ( 67)  |1011110                                      5e  [ 7]
+'D' ( 68)  |1011111                                      5f  [ 7]
+'E' ( 69)  |1100000                                      60  [ 7]
+'F' ( 70)  |1100001                                      61  [ 7]
+'G' ( 71)  |1100010                                      62  [ 7]
+'H' ( 72)  |1100011                                      63  [ 7]
+'I' ( 73)  |1100100                                      64  [ 7]
+'J' ( 74)  |1100101                                      65  [ 7]
+'K' ( 75)  |1100110                                      66  [ 7]
+'L' ( 76)  |1100111                                      67  [ 7]
+'M' ( 77)  |1101000                                      68  [ 7]
+'N' ( 78)  |1101001                                      69  [ 7]
+'O' ( 79)  |1101010                                      6a  [ 7]
+'P' ( 80)  |1101011                                      6b  [ 7]
+'Q' ( 81)  |1101100                                      6c  [ 7]
+'R' ( 82)  |1101101                                      6d  [ 7]
+'S' ( 83)  |1101110                                      6e  [ 7]
+'T' ( 84)  |1101111                                      6f  [ 7]
+'U' ( 85)  |1110000                                      70  [ 7]
+'V' ( 86)  |1110001                                      71  [ 7]
+'W' ( 87)  |1110010                                      72  [ 7]
+'X' ( 88)  |11111100                                     fc  [ 8]
+'Y' ( 89)  |1110011                                      73  [ 7]
+'Z' ( 90)  |11111101                                     fd  [ 8]
+'[' ( 91)  |11111111|11011                             1ffb  [13]
+'\' ( 92)  |11111111|11111110|000                     7fff0  [19]
+']' ( 93)  |11111111|11100                             1ffc  [13]
+'^' ( 94)  |11111111|111100                            3ffc  [14]
+'_' ( 95)  |100010                                       22  [ 6]
+'`' ( 96)  |11111111|1111101                           7ffd  [15]
+'a' ( 97)  |00011                                         3  [ 5]
+'b' ( 98)  |100011                                       23  [ 6]
+'c' ( 99)  |00100                                         4  [ 5]
+'d' (100)  |100100                                       24  [ 6]
+'e' (101)  |00101                                         5  [ 5]
+'f' (102)  |100101                                       25  [ 6]
+'g' (103)  |100110                                       26  [ 6]
+'h' (104)  |100111                                       27  [ 6]
+'i' (105)  |00110                                         6  [ 5]
+'j' (106)  |1110100                                      74  [ 7]
+'k' (107)  |1110101                                      75  [ 7]
+'l' (108)  |101000                                       28  [ 6]
+'m' (109)  |101001                                       29  [ 6]
+'n' (110)  |101010                                       2a  [ 6]
+'o' (111)  |00111                                         7  [ 5]
+'p' (112)  |101011                                       2b  [ 6]
+'q' (113)  |1110110                                      76  [ 7]
+'r' (114)  |101100                                       2c  [ 6]
+'s' (115)  |01000                                         8  [ 5]
+'t' (116)  |01001                                         9  [ 5]
+'u' (117)  |101101                                       2d  [ 6]
+'v' (118)  |1110111                                      77  [ 7]
+'w' (119)  |1111000                                      78  [ 7]
+'x' (120)  |1111001                                      79  [ 7]
+'y' (121)  |1111010                                      7a  [ 7]
+'z' (122)  |1111011                                      7b  [ 7]
+'{' (123)  |11111111|1111110                           7ffe  [15]
+'|' (124)  |11111111|100                                7fc  [11]
+'}' (125)  |11111111|111101                            3ffd  [14]
+'~' (126)  |11111111|11101                             1ffd  [13]
+    (127)  |11111111|11111111|11111111|1100         ffffffc  [28]
+    (128)  |11111111|11111110|0110                    fffe6  [20]
+    (129)  |11111111|11111111|010010                 3fffd2  [22]
+    (130)  |11111111|11111110|0111                    fffe7  [20]
+    (131)  |11111111|11111110|1000                    fffe8  [20]
+    (132)  |11111111|11111111|010011                 3fffd3  [22]
+    (133)  |11111111|11111111|010100                 3fffd4  [22]
+    (134)  |11111111|11111111|010101                 3fffd5  [22]
+    (135)  |11111111|11111111|1011001                7fffd9  [23]
+    (136)  |11111111|11111111|010110                 3fffd6  [22]
+    (137)  |11111111|11111111|1011010                7fffda  [23]
+    (138)  |11111111|11111111|1011011                7fffdb  [23]
+    (139)  |11111111|11111111|1011100                7fffdc  [23]
+    (140)  |11111111|11111111|1011101                7fffdd  [23]
+    (141)  |11111111|11111111|1011110                7fffde  [23]
+    (142)  |11111111|11111111|11101011               ffffeb  [24]
+    (143)  |11111111|11111111|1011111                7fffdf  [23]
+    (144)  |11111111|11111111|11101100               ffffec  [24]
+    (145)  |11111111|11111111|11101101               ffffed  [24]
+    (146)  |11111111|11111111|010111                 3fffd7  [22]
+    (147)  |11111111|11111111|1100000                7fffe0  [23]
+    (148)  |11111111|11111111|11101110               ffffee  [24]
+    (149)  |11111111|11111111|1100001                7fffe1  [23]
+    (150)  |11111111|11111111|1100010                7fffe2  [23]
+    (151)  |11111111|11111111|1100011                7fffe3  [23]
+    (152)  |11111111|11111111|1100100                7fffe4  [23]
+    (153)  |11111111|11111110|11100                  1fffdc  [21]
+    (154)  |11111111|11111111|011000                 3fffd8  [22]
+    (155)  |11111111|11111111|1100101                7fffe5  [23]
+    (156)  |11111111|11111111|011001                 3fffd9  [22]
+    (157)  |11111111|11111111|1100110                7fffe6  [23]
+    (158)  |11111111|11111111|1100111                7fffe7  [23]
+    (159)  |11111111|11111111|11101111               ffffef  [24]
+    (160)  |11111111|11111111|011010                 3fffda  [22]
+    (161)  |11111111|11111110|11101                  1fffdd  [21]
+    (162)  |11111111|11111110|1001                    fffe9  [20]
+    (163)  |11111111|11111111|011011                 3fffdb  [22]
+    (164)  |11111111|11111111|011100                 3fffdc  [22]
+    (165)  |11111111|11111111|1101000                7fffe8  [23]
+    (166)  |11111111|11111111|1101001                7fffe9  [23]
+    (167)  |11111111|11111110|11110                  1fffde  [21]
+    (168)  |11111111|11111111|1101010                7fffea  [23]
+    (169)  |11111111|11111111|011101                 3fffdd  [22]
+    (170)  |11111111|11111111|011110                 3fffde  [22]
+    (171)  |11111111|11111111|11110000               fffff0  [24]
+    (172)  |11111111|11111110|11111                  1fffdf  [21]
+    (173)  |11111111|11111111|011111                 3fffdf  [22]
+    (174)  |11111111|11111111|1101011                7fffeb  [23]
+    (175)  |11111111|11111111|1101100                7fffec  [23]
+    (176)  |11111111|11111111|00000                  1fffe0  [21]
+    (177)  |11111111|11111111|00001                  1fffe1  [21]
+    (178)  |11111111|11111111|100000                 3fffe0  [22]
+    (179)  |11111111|11111111|00010                  1fffe2  [21]
+    (180)  |11111111|11111111|1101101                7fffed  [23]
+    (181)  |11111111|11111111|100001                 3fffe1  [22]
+    (182)  |11111111|11111111|1101110                7fffee  [23]
+    (183)  |11111111|11111111|1101111                7fffef  [23]
+    (184)  |11111111|11111110|1010                    fffea  [20]
+    (185)  |11111111|11111111|100010                 3fffe2  [22]
+    (186)  |11111111|11111111|100011                 3fffe3  [22]
+    (187)  |11111111|11111111|100100                 3fffe4  [22]
+    (188)  |11111111|11111111|1110000                7ffff0  [23]
+    (189)  |11111111|11111111|100101                 3fffe5  [22]
+    (190)  |11111111|11111111|100110                 3fffe6  [22]
+    (191)  |11111111|11111111|1110001                7ffff1  [23]
+    (192)  |11111111|11111111|11111000|00           3ffffe0  [26]
+    (193)  |11111111|11111111|11111000|01           3ffffe1  [26]
+    (194)  |11111111|11111110|1011                    fffeb  [20]
+    (195)  |11111111|11111110|001                     7fff1  [19]
+    (196)  |11111111|11111111|100111                 3fffe7  [22]
+    (197)  |11111111|11111111|1110010                7ffff2  [23]
+    (198)  |11111111|11111111|101000                 3fffe8  [22]
+    (199)  |11111111|11111111|11110110|0            1ffffec  [25]
+    (200)  |11111111|11111111|11111000|10           3ffffe2  [26]
+    (201)  |11111111|11111111|11111000|11           3ffffe3  [26]
+    (202)  |11111111|11111111|11111001|00           3ffffe4  [26]
+    (203)  |11111111|11111111|11111011|110          7ffffde  [27]
+    (204)  |11111111|11111111|11111011|111          7ffffdf  [27]
+    (205)  |11111111|11111111|11111001|01           3ffffe5  [26]
+    (206)  |11111111|11111111|11110001               fffff1  [24]
+    (207)  |11111111|11111111|11110110|1            1ffffed  [25]
+    (208)  |11111111|11111110|010                     7fff2  [19]
+    (209)  |11111111|11111111|00011                  1fffe3  [21]
+    (210)  |11111111|11111111|11111001|10           3ffffe6  [26]
+    (211)  |11111111|11111111|11111100|000          7ffffe0  [27]
+    (212)  |11111111|11111111|11111100|001          7ffffe1  [27]
+    (213)  |11111111|11111111|11111001|11           3ffffe7  [26]
+    (214)  |11111111|11111111|11111100|010          7ffffe2  [27]
+    (215)  |11111111|11111111|11110010               fffff2  [24]
+    (216)  |11111111|11111111|00100                  1fffe4  [21]
+    (217)  |11111111|11111111|00101                  1fffe5  [21]
+    (218)  |11111111|11111111|11111010|00           3ffffe8  [26]
+    (219)  |11111111|11111111|11111010|01           3ffffe9  [26]
+    (220)  |11111111|11111111|11111111|1101         ffffffd  [28]
+    (221)  |11111111|11111111|11111100|011          7ffffe3  [27]
+    (222)  |11111111|11111111|11111100|100          7ffffe4  [27]
+    (223)  |11111111|11111111|11111100|101          7ffffe5  [27]
+    (224)  |11111111|11111110|1100                    fffec  [20]
+    (225)  |11111111|11111111|11110011               fffff3  [24]
+    (226)  |11111111|11111110|1101                    fffed  [20]
+    (227)  |11111111|11111111|00110                  1fffe6  [21]
+    (228)  |11111111|11111111|101001                 3fffe9  [22]
+    (229)  |11111111|11111111|00111                  1fffe7  [21]
+    (230)  |11111111|11111111|01000                  1fffe8  [21]
+    (231)  |11111111|11111111|1110011                7ffff3  [23]
+    (232)  |11111111|11111111|101010                 3fffea  [22]
+    (233)  |11111111|11111111|101011                 3fffeb  [22]
+    (234)  |11111111|11111111|11110111|0            1ffffee  [25]
+    (235)  |11111111|11111111|11110111|1            1ffffef  [25]
+    (236)  |11111111|11111111|11110100               fffff4  [24]
+    (237)  |11111111|11111111|11110101               fffff5  [24]
+    (238)  |11111111|11111111|11111010|10           3ffffea  [26]
+    (239)  |11111111|11111111|1110100                7ffff4  [23]
+    (240)  |11111111|11111111|11111010|11           3ffffeb  [26]
+    (241)  |11111111|11111111|11111100|110          7ffffe6  [27]
+    (242)  |11111111|11111111|11111011|00           3ffffec  [26]
+    (243)  |11111111|11111111|11111011|01           3ffffed  [26]
+    (244)  |11111111|11111111|11111100|111          7ffffe7  [27]
+    (245)  |11111111|11111111|11111101|000          7ffffe8  [27]
+    (246)  |11111111|11111111|11111101|001          7ffffe9  [27]
+    (247)  |11111111|11111111|11111101|010          7ffffea  [27]
+    (248)  |11111111|11111111|11111101|011          7ffffeb  [27]
+    (249)  |11111111|11111111|11111111|1110         ffffffe  [28]
+    (250)  |11111111|11111111|11111101|100          7ffffec  [27]
+    (251)  |11111111|11111111|11111101|101          7ffffed  [27]
+    (252)  |11111111|11111111|11111101|110          7ffffee  [27]
+    (253)  |11111111|11111111|11111101|111          7ffffef  [27]
+    (254)  |11111111|11111111|11111110|000          7fffff0  [27]
+    (255)  |11111111|11111111|11111011|10           3ffffee  [26]
+EOS (256)  |11111111|11111111|11111111|111111      3fffffff  [30]
+"""
 
 class Node:
+
     def __init__(self, term = None):
         self.term = term
         self.left = None
@@ -20,21 +283,18 @@ class Node:
         self.id = None
         self.accept = False
 
-def to_bin(s):
-    res = []
-    for i in range(0, len(s), 8):
-        x = s[i:i+8]
-        x += '0'*(8 - len(x))
-        a = 0
-        for j in range(8):
-            a *= 2
-            a += ord(x[j]) - ord('0')
-        res.append(a) #chr(a))
-    return res
+class Context:
 
-nodes = []
+    def __init__(self):
+        self.next_id_ = 0
+        self.root = Node()
 
-def insert(node, sym, bits):
+    def next_id(self):
+        id = self.next_id_
+        self.next_id_ += 1
+        return id
+
+def _add(node, sym, bits):
     if len(bits) == 0:
         node.term = sym
         return
@@ -47,67 +307,71 @@ def insert(node, sym, bits):
             if node.right is None:
                 node.right = Node()
             child = node.right
-        insert(child, sym, bits[1:])
+        _add(child, sym, bits[1:])
 
-def traverse(node, bits, syms, start_node, root, depth):
-    if depth == 4:
-        if 256 in syms:
-            syms = []
+def huffman_tree_add(ctx, sym, bits):
+    _add(ctx.root, sym, bits)
+
+def _set_node_id(ctx, node, prefix):
+    if node.term is not None:
+        return
+    if len(prefix) <= 7 and [1] * len(prefix) == prefix:
+        node.accept = True
+    node.id = ctx.next_id()
+    _set_node_id(ctx, node.left, prefix + [0])
+    _set_node_id(ctx, node.right, prefix + [1])
+
+def huffman_tree_set_node_id(ctx):
+    _set_node_id(ctx, ctx.root, [])
+
+def _traverse(node, sym, start_node, root, left):
+    if left == 0:
+        if sym == 256:
+            sym = None
             node = None
-        start_node.trans.append((node, bits, syms))
+        start_node.trans.append((node, sym))
         return
 
     if node.term is not None:
         node = root
 
-    def go(node, bit):
-        nbits = list(bits)
-        nbits.append(bit)
-        nsyms = list(syms)
+    def go(node):
         if node.term is not None:
-            nsyms.append(node.term)
-        traverse(node, nbits, nsyms, start_node, root, depth + 1)
+            assert sym is None
+            nsym = node.term
+        else:
+            nsym = sym
 
-    go(node.left, 0)
-    go(node.right, 1)
+        _traverse(node, nsym, start_node, root, left - 1)
 
-idseed = 0
+    go(node.left)
+    go(node.right)
 
-def dfs_setid(node, prefix):
-    if node.term is not None:
-        return
-    if len(prefix) <= 7 and [1] * len(prefix) == prefix:
-        node.accept = True
-    global idseed
-    node.id = idseed
-    idseed += 1
-    dfs_setid(node.left, prefix + [0])
-    dfs_setid(node.right, prefix + [1])
-
-def dfs(node, root):
+def _build_transition_table(ctx, node):
     if node is None:
         return
-    traverse(node, [], [], node, root, 0)
-    dfs(node.left, root)
-    dfs(node.right, root)
+    _traverse(node, None, node, ctx.root, 4)
+    _build_transition_table(ctx, node.left)
+    _build_transition_table(ctx, node.right)
+
+def huffman_tree_build_transition_table(ctx):
+    _build_transition_table(ctx, ctx.root)
 
 NGHTTP2_HUFF_ACCEPTED = 1
 NGHTTP2_HUFF_SYM = 1 << 1
 NGHTTP2_HUFF_FAIL = 1 << 2
 
-def dfs_print(node):
+def _print_transition_table(node):
     if node.term is not None:
         return
     print '/* {} */'.format(node.id)
     print '{'
-    for nd, bits, syms in node.trans:
-        outlen = len(syms)
+    for nd, sym in node.trans:
         flags = 0
-        if outlen == 0:
+        if sym is None:
             out = 0
         else:
-            assert(outlen == 1)
-            out = syms[0]
+            out = sym
             flags |= NGHTTP2_HUFF_SYM
         if nd is None:
             id = 0
@@ -122,52 +386,50 @@ def dfs_print(node):
                 flags |= NGHTTP2_HUFF_ACCEPTED
         print '  {{{}, 0x{:02x}, {}}},'.format(id, flags, out)
     print '},'
-    dfs_print(node.left)
-    dfs_print(node.right)
+    _print_transition_table(node.left)
+    _print_transition_table(node.right)
 
-symbol_tbl = [(None, 0) for i in range(257)]
-tables = {}
+def huffman_tree_print_transition_table(ctx):
+    _print_transition_table(ctx.root)
 
-root = Node()
+if __name__ == '__main__':
+    ctx = Context()
+    symbol_tbl = [(None, 0) for i in range(257)]
 
-for line in sys.stdin:
-    m = re.match(r'.*\(\s*(\d+)\)\s+([|01]+)\s+(\S+)\s+\[\s*(\d+)\].*', line)
-    if m:
-        #print m.group(1), m.group(2), m.group(4)
-        if len(m.group(3)) > 8:
-            raise Error('Code is more than 4 bytes long')
-        sym = int(m.group(1))
-        bits = re.sub(r'\|', '', m.group(2))
-        nbits = int(m.group(4))
-        assert(len(bits) == nbits)
-        binpat = to_bin(bits)
-        assert(len(binpat) == (nbits+7)/8)
-        symbol_tbl[sym] = (binpat, nbits, m.group(3))
-        #print "Inserting", sym
-        insert(root, sym, bits)
+    for line in StringIO.StringIO(HUFFMAN_CODE_TABLE):
+        m = re.match(
+            r'.*\(\s*(\d+)\)\s+([|01]+)\s+(\S+)\s+\[\s*(\d+)\].*', line)
+        if m:
+            sym = int(m.group(1))
+            bits = re.sub(r'\|', '', m.group(2))
+            code = m.group(3)
+            nbits = int(m.group(4))
+            if len(code) > 8:
+                raise Error('Code is more than 4 bytes long')
+            assert(len(bits) == nbits)
+            symbol_tbl[sym] = (nbits, code)
+            huffman_tree_add(ctx, sym, bits)
 
-dfs_setid(root, [])
-dfs(root, root)
+    huffman_tree_set_node_id(ctx)
+    huffman_tree_build_transition_table(ctx)
 
-print '''\
+    print '''\
 typedef struct {
   uint32_t nbits;
   uint32_t code;
 } nghttp2_huff_sym;
 '''
 
-print '''\
-const nghttp2_huff_sym huff_sym_table[] = {'''
-for i in range(257):
-    pat = list(symbol_tbl[i][0])
-    pat += [0]*(4 - len(pat))
     print '''\
+const nghttp2_huff_sym huff_sym_table[] = {'''
+    for i in range(257):
+        print '''\
   {{ {}, 0x{}u }}{}\
-'''.format(symbol_tbl[i][1], symbol_tbl[i][2], ',' if i < 256 else '')
-print '};'
-print ''
+'''.format(symbol_tbl[i][0], symbol_tbl[i][1], ',' if i < 256 else '')
+    print '};'
+    print ''
 
-print '''\
+    print '''\
 enum {{
   NGHTTP2_HUFF_ACCEPTED = {},
   NGHTTP2_HUFF_SYM = {},
@@ -175,7 +437,7 @@ enum {{
 }} nghttp2_huff_decode_flag;
 '''.format(NGHTTP2_HUFF_ACCEPTED, NGHTTP2_HUFF_SYM, NGHTTP2_HUFF_FAIL)
 
-print '''\
+    print '''\
 typedef struct {
   uint8_t state;
   uint8_t flags;
@@ -183,7 +445,7 @@ typedef struct {
 } nghttp2_huff_decode;
 '''
 
-print '''\
+    print '''\
 const nghttp2_huff_decode huff_decode_table[][16] = {'''
-dfs_print(root)
-print '};'
+    huffman_tree_print_transition_table(ctx)
+    print '};'
diff --git a/src/asio_io_service_pool.cc b/src/asio_io_service_pool.cc
index c6936d08..b6735df0 100644
--- a/src/asio_io_service_pool.cc
+++ b/src/asio_io_service_pool.cc
@@ -35,8 +35,6 @@
 //
 #include "asio_io_service_pool.h"
 
-#include <future>
-
 namespace nghttp2 {
 
 namespace asio_http2 {
@@ -56,19 +54,23 @@ io_service_pool::io_service_pool(std::size_t pool_size) : next_io_service_(0) {
   }
 }
 
-void io_service_pool::run() {
+void io_service_pool::run(bool asynchronous) {
   // Create a pool of threads to run all of the io_services.
-  auto futs = std::vector<std::future<std::size_t>>();
-
   for (std::size_t i = 0; i < io_services_.size(); ++i) {
-    futs.push_back(std::async(std::launch::async,
+    futures_.push_back(std::async(std::launch::async,
                               (size_t (boost::asio::io_service::*)(void)) &
                                   boost::asio::io_service::run,
                               io_services_[i]));
   }
 
+  if (!asynchronous) {
+    join();
+  }
+}
+
+void io_service_pool::join() {
   // Wait for all threads in the pool to exit.
-  for (auto &fut : futs) {
+  for (auto &fut : futures_) {
     fut.get();
   }
 }
diff --git a/src/asio_io_service_pool.h b/src/asio_io_service_pool.h
index 7ebd883c..242cac8f 100644
--- a/src/asio_io_service_pool.h
+++ b/src/asio_io_service_pool.h
@@ -41,6 +41,7 @@
 
 #include <vector>
 #include <memory>
+#include <future>
 
 #include <boost/noncopyable.hpp>
 #include <boost/thread.hpp>
@@ -58,11 +59,14 @@ public:
   explicit io_service_pool(std::size_t pool_size);
 
   /// Run all io_service objects in the pool.
-  void run();
+  void run(bool asynchronous = false);
 
   /// Stop all io_service objects in the pool.
   void stop();
 
+  /// Join on all io_service objects in the pool.
+  void join();
+
   /// Get an io_service to use.
   boost::asio::io_service &get_io_service();
 
@@ -75,6 +79,9 @@ private:
 
   /// The next io_service to use for a connection.
   std::size_t next_io_service_;
+
+  /// Futures to all the io_service objects
+  std::vector<std::future<std::size_t>> futures_;
 };
 
 } // namespace asio_http2
diff --git a/src/asio_server.cc b/src/asio_server.cc
index 323a8991..1f10cd5f 100644
--- a/src/asio_server.cc
+++ b/src/asio_server.cc
@@ -50,7 +50,7 @@ boost::system::error_code
 server::listen_and_serve(boost::system::error_code &ec,
                          boost::asio::ssl::context *tls_context,
                          const std::string &address, const std::string &port,
-                         int backlog, serve_mux &mux) {
+                         int backlog, serve_mux &mux, bool asynchronous) {
   ec.clear();
 
   if (bind_and_listen(ec, address, port, backlog)) {
@@ -65,7 +65,7 @@ server::listen_and_serve(boost::system::error_code &ec,
     }
   }
 
-  io_service_pool_.run();
+  io_service_pool_.run(asynchronous);
 
   return ec;
 }
@@ -156,6 +156,16 @@ void server::start_accept(tcp::acceptor &acceptor, serve_mux &mux) {
   });
 }
 
+void server::stop()
+{
+  io_service_pool_.stop();
+}
+
+void server::join()
+{
+  io_service_pool_.join();
+}
+
 } // namespace server
 } // namespace asio_http2
 } // namespace nghttp2
diff --git a/src/asio_server.h b/src/asio_server.h
index bb4159e9..7f601201 100644
--- a/src/asio_server.h
+++ b/src/asio_server.h
@@ -69,7 +69,9 @@ public:
   listen_and_serve(boost::system::error_code &ec,
                    boost::asio::ssl::context *tls_context,
                    const std::string &address, const std::string &port,
-                   int backlog, serve_mux &mux);
+                   int backlog, serve_mux &mux, bool asynchronous = false);
+  void join();
+  void stop();
 
 private:
   /// Initiate an asynchronous accept operation.
diff --git a/src/asio_server_http2.cc b/src/asio_server_http2.cc
index 92bc8898..85e50221 100644
--- a/src/asio_server_http2.cc
+++ b/src/asio_server_http2.cc
@@ -54,15 +54,17 @@ http2 &http2::operator=(http2 &&other) noexcept {
 
 boost::system::error_code http2::listen_and_serve(boost::system::error_code &ec,
                                                   const std::string &address,
-                                                  const std::string &port) {
-  return impl_->listen_and_serve(ec, nullptr, address, port);
+                                                  const std::string &port,
+                                                  bool asynchronous) {
+  return impl_->listen_and_serve(ec, nullptr, address, port, asynchronous);
 }
 
 boost::system::error_code
 http2::listen_and_serve(boost::system::error_code &ec,
                         boost::asio::ssl::context &tls_context,
-                        const std::string &address, const std::string &port) {
-  return impl_->listen_and_serve(ec, &tls_context, address, port);
+                        const std::string &address, const std::string &port,
+                        bool asynchronous) {
+  return impl_->listen_and_serve(ec, &tls_context, address, port, asynchronous);
 }
 
 void http2::num_threads(size_t num_threads) { impl_->num_threads(num_threads); }
@@ -73,6 +75,16 @@ bool http2::handle(std::string pattern, request_cb cb) {
   return impl_->handle(std::move(pattern), std::move(cb));
 }
 
+void http2::stop()
+{
+  impl_->stop();
+}
+
+void http2::join()
+{
+  return impl_->join();
+}
+
 } // namespace server
 
 } // namespace asio_http2
diff --git a/src/asio_server_http2_impl.cc b/src/asio_server_http2_impl.cc
index 96ca2432..142f418c 100644
--- a/src/asio_server_http2_impl.cc
+++ b/src/asio_server_http2_impl.cc
@@ -41,9 +41,9 @@ http2_impl::http2_impl() : num_threads_(1), backlog_(-1) {}
 
 boost::system::error_code http2_impl::listen_and_serve(
     boost::system::error_code &ec, boost::asio::ssl::context *tls_context,
-    const std::string &address, const std::string &port) {
-  return server(num_threads_)
-      .listen_and_serve(ec, tls_context, address, port, backlog_, mux_);
+    const std::string &address, const std::string &port, bool asynchronous) {
+  server_.reset(new server(num_threads_));
+  return server_->listen_and_serve(ec, tls_context, address, port, backlog_, mux_, asynchronous);
 }
 
 void http2_impl::num_threads(size_t num_threads) { num_threads_ = num_threads; }
@@ -54,6 +54,15 @@ bool http2_impl::handle(std::string pattern, request_cb cb) {
   return mux_.handle(std::move(pattern), std::move(cb));
 }
 
+void http2_impl::stop() {
+  return server_->stop();
+}
+
+void http2_impl::join()
+{
+  return server_->join();
+}
+
 } // namespace server
 
 } // namespace asio_http2
diff --git a/src/asio_server_http2_impl.h b/src/asio_server_http2_impl.h
index f097aea0..244486fa 100644
--- a/src/asio_server_http2_impl.h
+++ b/src/asio_server_http2_impl.h
@@ -45,10 +45,13 @@ public:
   boost::system::error_code
   listen_and_serve(boost::system::error_code &ec,
                    boost::asio::ssl::context *tls_context,
-                   const std::string &address, const std::string &port);
+                   const std::string &address, const std::string &port,
+                   bool asynchronous);
   void num_threads(size_t num_threads);
   void backlog(int backlog);
   bool handle(std::string pattern, request_cb cb);
+  void stop();
+  void join();
 
 private:
   std::unique_ptr<server> server_;
diff --git a/src/includes/nghttp2/asio_http2_server.h b/src/includes/nghttp2/asio_http2_server.h
index bef17336..1c5a71fd 100644
--- a/src/includes/nghttp2/asio_http2_server.h
+++ b/src/includes/nghttp2/asio_http2_server.h
@@ -136,17 +136,25 @@ public:
   http2 &operator=(http2 &&other) noexcept;
 
   // Starts listening connection on given address and port and serves
-  // incoming requests in cleartext TCP connection.
+  // incoming requests in cleartext TCP connection.  If |asynchronous|
+  // is false, this function blocks forever unless there is an error.
+  // If it is true, after server has started, this function returns
+  // immediately, and the caller should call join() to shutdown server
+  // gracefully.
   boost::system::error_code listen_and_serve(boost::system::error_code &ec,
                                              const std::string &address,
-                                             const std::string &port);
+                                             const std::string &port,
+                                             bool asynchronous = false);
 
   // Starts listening connection on given address and port and serves
-  // incoming requests in SSL/TLS encrypted connection.
+  // incoming requests in SSL/TLS encrypted connection.  For
+  // |asynchronous| parameter, see cleartext version
+  // |listen_and_serve|.
   boost::system::error_code
   listen_and_serve(boost::system::error_code &ec,
                    boost::asio::ssl::context &tls_context,
-                   const std::string &address, const std::string &port);
+                   const std::string &address, const std::string &port,
+                   bool asynchronous = false);
 
   // Registers request handler |cb| with path pattern |pattern|.  This
   // function will fail and returns false if same pattern has been
@@ -187,6 +195,12 @@ public:
   // connections.
   void backlog(int backlog);
 
+  // Gracefully stop http2 server
+  void stop();
+
+  // Join on http2 server and wait for it to fully stop
+  void join();
+
 private:
   std::unique_ptr<http2_impl> impl_;
 };
diff --git a/src/shrpx_downstream.h b/src/shrpx_downstream.h
index 1f55cd40..718c8bd2 100644
--- a/src/shrpx_downstream.h
+++ b/src/shrpx_downstream.h
@@ -287,7 +287,7 @@ public:
   int change_priority(int32_t pri);
 
   // Maximum buffer size for header name/value pairs.
-  static const size_t MAX_HEADERS_SUM = 32768;
+  static constexpr size_t MAX_HEADERS_SUM = 128 * 1024;
 
   bool get_rst_stream_after_end_stream() const;
   void set_rst_stream_after_end_stream(bool f);
diff --git a/tests/main.c b/tests/main.c
index 396c0081..b1ef7743 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -262,6 +262,8 @@ int main(int argc _U_, char *argv[] _U_) {
                    test_nghttp2_session_reset_pending_headers) ||
       !CU_add_test(pSuite, "session_send_data_callback",
                    test_nghttp2_session_send_data_callback) ||
+      !CU_add_test(pSuite, "session_on_begin_headers_temporal_failure",
+                   test_nghttp2_session_on_begin_headers_temporal_failure) ||
       !CU_add_test(pSuite, "http_mandatory_headers",
                    test_nghttp2_http_mandatory_headers) ||
       !CU_add_test(pSuite, "http_content_length",
diff --git a/tests/nghttp2_session_test.c b/tests/nghttp2_session_test.c
index 08fc9829..77ea389e 100644
--- a/tests/nghttp2_session_test.c
+++ b/tests/nghttp2_session_test.c
@@ -407,6 +407,12 @@ static int on_begin_headers_callback(nghttp2_session *session _U_,
   return 0;
 }
 
+static int temporal_failure_on_begin_headers_callback(
+    nghttp2_session *session, const nghttp2_frame *frame, void *user_data) {
+  on_begin_headers_callback(session, frame, user_data);
+  return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
+}
+
 static ssize_t defer_data_source_read_callback(nghttp2_session *session _U_,
                                                int32_t stream_id _U_,
                                                uint8_t *buf _U_, size_t len _U_,
@@ -6707,21 +6713,50 @@ void test_nghttp2_session_on_header_temporal_failure(void) {
 
   nghttp2_frame_pack_frame_hd(&buf->pos[hdpos], &hd);
 
+  ud.header_cb_called = 0;
   rv = nghttp2_session_mem_recv(session, buf->pos, nghttp2_bufs_len(&bufs));
 
   CU_ASSERT(rv == nghttp2_bufs_len(&bufs));
+  CU_ASSERT(1 == ud.header_cb_called);
 
   item = nghttp2_session_get_next_ob_item(session);
 
   CU_ASSERT(NGHTTP2_RST_STREAM == item->frame.hd.type);
+  CU_ASSERT(1 == item->frame.hd.stream_id);
 
   /* Make sure no header decompression error occurred */
   CU_ASSERT(NGHTTP2_GOAWAY_NONE == session->goaway_flags);
 
-  nghttp2_bufs_free(&bufs);
-
   nghttp2_hd_deflate_free(&deflater);
   nghttp2_session_del(session);
+
+  nghttp2_bufs_reset(&bufs);
+
+  /* Check for PUSH_PROMISE */
+  nghttp2_hd_deflate_init(&deflater, mem);
+  nghttp2_session_client_new(&session, &callbacks, &ud);
+
+  nghttp2_session_open_stream(session, 1, NGHTTP2_STREAM_FLAG_NONE,
+                              &pri_spec_default, NGHTTP2_STREAM_OPENING, NULL);
+
+  rv = pack_push_promise(&bufs, &deflater, 1, NGHTTP2_FLAG_END_HEADERS, 2,
+                         reqnv, ARRLEN(reqnv), mem);
+  CU_ASSERT(0 == rv);
+
+  ud.header_cb_called = 0;
+  rv = nghttp2_session_mem_recv(session, bufs.head->buf.pos,
+                                nghttp2_bufs_len(&bufs));
+  CU_ASSERT(nghttp2_bufs_len(&bufs) == rv);
+  CU_ASSERT(1 == ud.header_cb_called);
+
+  item = nghttp2_session_get_next_ob_item(session);
+  CU_ASSERT(NGHTTP2_RST_STREAM == item->frame.hd.type);
+  CU_ASSERT(2 == item->frame.hd.stream_id);
+  CU_ASSERT(NGHTTP2_INTERNAL_ERROR == item->frame.rst_stream.error_code);
+
+  nghttp2_session_del(session);
+  nghttp2_hd_deflate_free(&deflater);
+  nghttp2_bufs_free(&bufs);
 }
 
 void test_nghttp2_session_recv_client_magic(void) {
@@ -7031,6 +7066,78 @@ void test_nghttp2_session_send_data_callback(void) {
   nghttp2_session_del(session);
 }
 
+void test_nghttp2_session_on_begin_headers_temporal_failure(void) {
+  nghttp2_session *session;
+  nghttp2_session_callbacks callbacks;
+  my_user_data ud;
+  nghttp2_bufs bufs;
+  nghttp2_mem *mem;
+  ssize_t rv;
+  nghttp2_hd_deflater deflater;
+  nghttp2_outbound_item *item;
+
+  mem = nghttp2_mem_default();
+  frame_pack_bufs_init(&bufs);
+  nghttp2_hd_deflate_init(&deflater, mem);
+
+  memset(&callbacks, 0, sizeof(nghttp2_session_callbacks));
+  callbacks.on_begin_headers_callback =
+      temporal_failure_on_begin_headers_callback;
+  callbacks.on_header_callback = on_header_callback;
+  callbacks.on_frame_recv_callback = on_frame_recv_callback;
+  callbacks.send_callback = null_send_callback;
+  nghttp2_session_server_new(&session, &callbacks, &ud);
+
+  rv = pack_headers(&bufs, &deflater, 1, NGHTTP2_FLAG_END_HEADERS, reqnv,
+                    ARRLEN(reqnv), mem);
+  CU_ASSERT(0 == rv);
+
+  ud.header_cb_called = 0;
+  ud.frame_recv_cb_called = 0;
+  rv = nghttp2_session_mem_recv(session, bufs.head->buf.pos,
+                                nghttp2_bufs_len(&bufs));
+  CU_ASSERT(nghttp2_bufs_len(&bufs) == rv);
+  CU_ASSERT(0 == ud.header_cb_called);
+  CU_ASSERT(0 == ud.frame_recv_cb_called);
+
+  item = nghttp2_session_get_next_ob_item(session);
+  CU_ASSERT(NGHTTP2_RST_STREAM == item->frame.hd.type);
+  CU_ASSERT(1 == item->frame.hd.stream_id);
+  CU_ASSERT(NGHTTP2_INTERNAL_ERROR == item->frame.rst_stream.error_code);
+
+  nghttp2_session_del(session);
+  nghttp2_hd_deflate_free(&deflater);
+
+  nghttp2_bufs_reset(&bufs);
+  /* check for PUSH_PROMISE */
+  nghttp2_hd_deflate_init(&deflater, mem);
+  nghttp2_session_client_new(&session, &callbacks, &ud);
+
+  nghttp2_session_open_stream(session, 1, NGHTTP2_STREAM_FLAG_NONE,
+                              &pri_spec_default, NGHTTP2_STREAM_OPENING, NULL);
+
+  rv = pack_push_promise(&bufs, &deflater, 1, NGHTTP2_FLAG_END_HEADERS, 2,
+                         reqnv, ARRLEN(reqnv), mem);
+  CU_ASSERT(0 == rv);
+
+  ud.header_cb_called = 0;
+  ud.frame_recv_cb_called = 0;
+  rv = nghttp2_session_mem_recv(session, bufs.head->buf.pos,
+                                nghttp2_bufs_len(&bufs));
+  CU_ASSERT(nghttp2_bufs_len(&bufs) == rv);
+  CU_ASSERT(0 == ud.header_cb_called);
+  CU_ASSERT(0 == ud.frame_recv_cb_called);
+
+  item = nghttp2_session_get_next_ob_item(session);
+  CU_ASSERT(NGHTTP2_RST_STREAM == item->frame.hd.type);
+  CU_ASSERT(2 == item->frame.hd.stream_id);
+  CU_ASSERT(NGHTTP2_INTERNAL_ERROR == item->frame.rst_stream.error_code);
+
+  nghttp2_session_del(session);
+  nghttp2_hd_deflate_free(&deflater);
+  nghttp2_bufs_free(&bufs);
+}
+
 static void check_nghttp2_http_recv_headers_fail(
     nghttp2_session *session, nghttp2_hd_deflater *deflater, int32_t stream_id,
     int stream_state, const nghttp2_nv *nva, size_t nvlen) {
diff --git a/tests/nghttp2_session_test.h b/tests/nghttp2_session_test.h
index 406cfb78..e879c783 100644
--- a/tests/nghttp2_session_test.h
+++ b/tests/nghttp2_session_test.h
@@ -124,6 +124,7 @@ void test_nghttp2_session_open_idle_stream(void);
 void test_nghttp2_session_cancel_reserved_remote(void);
 void test_nghttp2_session_reset_pending_headers(void);
 void test_nghttp2_session_send_data_callback(void);
+void test_nghttp2_session_on_begin_headers_temporal_failure(void);
 void test_nghttp2_http_mandatory_headers(void);
 void test_nghttp2_http_content_length(void);
 void test_nghttp2_http_content_length_mismatch(void);