Merge branch 'nghttpx-server-push'

doc/h2load.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "H2LOAD" "1" "February 01, 2015" "0.7.4-DEV" "nghttp2"
+.TH "H2LOAD" "1" "February 08, 2015" "0.7.4-DEV" "nghttp2"
 .SH NAME
 h2load \- HTTP/2 benchmarking tool
 .

doc/nghttp.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "NGHTTP" "1" "February 01, 2015" "0.7.4-DEV" "nghttp2"
+.TH "NGHTTP" "1" "February 08, 2015" "0.7.4-DEV" "nghttp2"
 .SH NAME
 nghttp \- HTTP/2 experimental client
 .

doc/nghttpd.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "NGHTTPD" "1" "February 01, 2015" "0.7.4-DEV" "nghttp2"
+.TH "NGHTTPD" "1" "February 08, 2015" "0.7.4-DEV" "nghttp2"
 .SH NAME
 nghttpd \- HTTP/2 experimental server
 .

doc/nghttpx.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "NGHTTPX" "1" "February 01, 2015" "0.7.4-DEV" "nghttp2"
+.TH "NGHTTPX" "1" "February 08, 2015" "0.7.4-DEV" "nghttp2"
 .SH NAME
 nghttpx \- HTTP/2 experimental proxy
 .
@@ -500,6 +500,13 @@ padding.  Specify 0 to  disable padding.  This option is
 meant for debugging purpose  and not intended to enhance
 protocol security.
 .UNINDENT
+.INDENT 0.0
+.TP
+.B \-\-no\-server\-push
+Disable  HTTP/2  server  push.    Server  push  is  only
+supported  by default  mode and  HTTP/2 frontend.   SPDY
+frontend does not support server push.
+.UNINDENT
 .SS Mode
 .INDENT 0.0
 .TP
@@ -652,6 +659,14 @@ altered regardless of this option.
 .UNINDENT
 .INDENT 0.0
 .TP
+.B \-\-no\-host\-rewrite
+Don\(aqt  rewrite  host  and :authority  header  fields  on
+\fI\%\-\-http2\-bridge\fP,   \fI\%\-\-client\fP   and  default   mode.    For
+\fI\%\-\-http2\-proxy\fP  and  \fI\%\-\-client\-proxy\fP mode,  these  headers
+will not be altered regardless of this option.
+.UNINDENT
+.INDENT 0.0
+.TP
 .B \-\-altsvc=<PROTOID,PORT[,HOST,[ORIGIN]]>
 Specify   protocol  ID,   port,  host   and  origin   of
 alternative service.  <HOST>  and <ORIGIN> are optional.
@@ -782,6 +797,39 @@ path with same command\-line arguments and environment variables.
 After new process comes up, sending SIGQUIT to the original process
 to perform hot swapping.
 .UNINDENT
+.SH SERVER PUSH
+.sp
+nghttpx supports HTTP/2 server push in default mode.  nghttpx looks
+for Link header field (\fI\%RFC 5988\fP) in response headers for
+backend server and extracts URI\-reference with parameter
+\fBrel=preload\fP (see \fI\%preload\fP)
+and pushes those URIs to the frontend client. Here is a sample Link
+header field to initiate server push:
+.INDENT 0.0
+.INDENT 3.5
+.sp
+.nf
+.ft C
+Link: </fonts/font.woff>; rel=preload
+Link: </css/theme.css>; rel=preload
+.ft P
+.fi
+.UNINDENT
+.UNINDENT
+.sp
+Currently, the following restrictions are applied for server push:
+.INDENT 0.0
+.IP 1. 3
+URI\-reference must not contain authority.  If it exists, it is not
+pushed.  \fB/fonts/font.woff\fP and \fBcss/theme.css\fP are eligible to
+be pushed.  \fBhttps://example.org/fonts/font.woff\fP and
+\fB//example.org/css/theme.css\fP are not.
+.IP 2. 3
+The associated stream must have method "GET" or "POST".  The
+associated stream\(aqs status code must be 200.
+.UNINDENT
+.sp
+These limitations may be loosened in the future release.
 .SH SEE ALSO
 .sp
 \fInghttp(1)\fP, \fInghttpd(1)\fP, \fIh2load(1)\fP

doc/nghttpx.1.rst

@@ -438,6 +438,12 @@ HTTP/2 and SPDY
     meant for debugging purpose  and not intended to enhance
     protocol security.
 
+.. option:: --no-server-push
+
+    Disable  HTTP/2  server  push.    Server  push  is  only
+    supported  by default  mode and  HTTP/2 frontend.   SPDY
+    frontend does not support server push.
+
 
 Mode
 ~~~~
@@ -570,6 +576,13 @@ HTTP
     :option:`--client-proxy` mode,  location header field will  not be
     altered regardless of this option.
 
+.. option:: --no-host-rewrite
+
+    Don't  rewrite  host  and :authority  header  fields  on
+    :option:`--http2-bridge`\,   :option:`--client`   and  default   mode.    For
+    :option:`--http2-proxy`  and  :option:`\--client-proxy` mode,  these  headers
+    will not be altered regardless of this option.
+
 .. option:: --altsvc=<PROTOID,PORT[,HOST,[ORIGIN]]>
 
     Specify   protocol  ID,   port,  host   and  origin   of
@@ -701,6 +714,35 @@ SIGUSR2
   After new process comes up, sending SIGQUIT to the original process
   to perform hot swapping.
 
+SERVER PUSH
+-----------
+
+nghttpx supports HTTP/2 server push in default mode.  nghttpx looks
+for Link header field (`RFC 5988
+<http://tools.ietf.org/html/rfc5988>`_) in response headers for
+backend server and extracts URI-reference with parameter
+``rel=preload`` (see `preload
+<http://w3c.github.io/preload/#interoperability-with-http-link-header>`_)
+and pushes those URIs to the frontend client. Here is a sample Link
+header field to initiate server push:
+
+.. code-block:: http
+
+  Link: </fonts/font.woff>; rel=preload
+  Link: </css/theme.css>; rel=preload
+
+Currently, the following restrictions are applied for server push:
+
+1. URI-reference must not contain authority.  If it exists, it is not
+   pushed.  ``/fonts/font.woff`` and ``css/theme.css`` are eligible to
+   be pushed.  ``https://example.org/fonts/font.woff`` and
+   ``//example.org/css/theme.css`` are not.
+
+2. The associated stream must have method "GET" or "POST".  The
+   associated stream's status code must be 200.
+
+These limitations may be loosened in the future release.
+
 SEE ALSO
 --------
 

doc/nghttpx.h2r

@@ -42,6 +42,35 @@ SIGUSR2
   After new process comes up, sending SIGQUIT to the original process
   to perform hot swapping.
 
+SERVER PUSH
+-----------
+
+nghttpx supports HTTP/2 server push in default mode.  nghttpx looks
+for Link header field (`RFC 5988
+<http://tools.ietf.org/html/rfc5988>`_) in response headers for
+backend server and extracts URI-reference with parameter
+``rel=preload`` (see `preload
+<http://w3c.github.io/preload/#interoperability-with-http-link-header>`_)
+and pushes those URIs to the frontend client. Here is a sample Link
+header field to initiate server push:
+
+.. code-block:: http
+
+  Link: </fonts/font.woff>; rel=preload
+  Link: </css/theme.css>; rel=preload
+
+Currently, the following restrictions are applied for server push:
+
+1. URI-reference must not contain authority.  If it exists, it is not
+   pushed.  ``/fonts/font.woff`` and ``css/theme.css`` are eligible to
+   be pushed.  ``https://example.org/fonts/font.woff`` and
+   ``//example.org/css/theme.css`` are not.
+
+2. The associated stream must have method "GET" or "POST".  The
+   associated stream's status code must be 200.
+
+These limitations may be loosened in the future release.
+
 SEE ALSO
 --------
 

genheaderfunc.py

@@ -21,6 +21,11 @@ HEADERS = [
     "content-length",
     "location",
     "trailer",
+    "link",
+    "accept-encoding",
+    "accept-language",
+    "cache-control",
+    "user-agent",
     # disallowed h1 headers
     'connection',
     'keep-alive',

integration-tests/nghttpx_http2_test.go

@@ -473,6 +473,9 @@ func TestH2H1TEGzip(t *testing.T) {
 	}
 }
 
+// TestH2H1SNI tests server's TLS SNI extension feature.  It must
+// choose appropriate certificate depending on the indicated
+// server_name from client.
 func TestH2H1SNI(t *testing.T) {
 	st := newServerTesterTLSConfig([]string{"--subcert=" + testDir + "/alt-server.key:" + testDir + "/alt-server.crt"}, t, noopHandler, &tls.Config{
 		ServerName: "alt-domain",
@@ -488,6 +491,37 @@ func TestH2H1SNI(t *testing.T) {
 	}
 }
 
+// TestH2H1ServerPush tests server push using Link header field from
+// backend server.
+func TestH2H1ServerPush(t *testing.T) {
+	st := newServerTester(nil, t, func(w http.ResponseWriter, r *http.Request) {
+		// only resources marked as rel=preload are pushed
+		w.Header().Add("Link", "</css/main.css>; rel=preload, </foo>, </css/theme.css>; rel=preload")
+	})
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1ServerPush",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+	if got, want := res.status, 200; got != want {
+		t.Errorf("res.status: %v; want %v", got, want)
+	}
+	if got, want := len(res.pushResponse), 2; got != want {
+		t.Fatalf("len(res.pushResponse): %v; want %v", got, want)
+	}
+	mainCSS := res.pushResponse[0]
+	if got, want := mainCSS.status, 200; got != want {
+		t.Errorf("mainCSS.status: %v; want %v", got, want)
+	}
+	themeCSS := res.pushResponse[1]
+	if got, want := themeCSS.status, 200; got != want {
+		t.Errorf("themeCSS.status: %v; want %v", got, want)
+	}
+}
+
 // TestH2H1GracefulShutdown tests graceful shutdown.
 func TestH2H1GracefulShutdown(t *testing.T) {
 	st := newServerTester(nil, t, noopHandler)

integration-tests/server_tester.go

@@ -17,6 +17,7 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"os/exec"
+	"sort"
 	"strconv"
 	"strings"
 	"testing"
@@ -411,7 +412,6 @@ loop:
 }
 
 func (st *serverTester) http2(rp requestParam) (*serverResponse, error) {
-	res := &serverResponse{}
 	st.headerBlkBuf.Reset()
 	st.header = make(http.Header)
 
@@ -434,6 +434,13 @@ func (st *serverTester) http2(rp requestParam) (*serverResponse, error) {
 		}
 	}
 
+	res := &serverResponse{
+		streamID: id,
+	}
+
+	streams := make(map[uint32]*serverResponse)
+	streams[id] = res
+
 	method := "GET"
 	if rp.method != "" {
 		method = rp.method
@@ -493,34 +500,53 @@ loop:
 			if err != nil {
 				return res, err
 			}
-			if f.FrameHeader.StreamID != id {
+			sr, ok := streams[f.FrameHeader.StreamID]
+			if !ok {
 				st.header = make(http.Header)
 				break
 			}
-			res.header = cloneHeader(st.header)
+			sr.header = cloneHeader(st.header)
 			var status int
-			status, err = strconv.Atoi(res.header.Get(":status"))
+			status, err = strconv.Atoi(sr.header.Get(":status"))
 			if err != nil {
 				return res, fmt.Errorf("Error parsing status code: %v", err)
 			}
-			res.status = status
+			sr.status = status
 			if f.StreamEnded() {
-				break loop
+				if streamEnded(res, streams, sr) {
+					break loop
+				}
 			}
+		case *http2.PushPromiseFrame:
+			_, err := st.dec.Write(f.HeaderBlockFragment())
+			if err != nil {
+				return res, err
+			}
+			sr := &serverResponse{
+				streamID:  f.PromiseID,
+				reqHeader: cloneHeader(st.header),
+			}
+			streams[sr.streamID] = sr
 		case *http2.DataFrame:
-			if f.FrameHeader.StreamID != id {
+			sr, ok := streams[f.FrameHeader.StreamID]
+			if !ok {
 				break
 			}
-			res.body = append(res.body, f.Data()...)
+			sr.body = append(sr.body, f.Data()...)
 			if f.StreamEnded() {
-				break loop
+				if streamEnded(res, streams, sr) {
+					break loop
+				}
 			}
 		case *http2.RSTStreamFrame:
-			if f.FrameHeader.StreamID != id {
+			sr, ok := streams[f.FrameHeader.StreamID]
+			if !ok {
 				break
 			}
-			res.errCode = f.ErrCode
+			sr.errCode = f.ErrCode
-			break loop
+			if streamEnded(res, streams, sr) {
+				break loop
+			}
 		case *http2.GoAwayFrame:
 			if f.ErrCode == http2.ErrCodeNo {
 				break
@@ -535,21 +561,46 @@ loop:
 			if err := st.fr.WriteSettingsAck(); err != nil {
 				return res, err
 			}
-			// TODO handle PUSH_PROMISE as well, since it alters HPACK context
 		}
 	}
+	sort.Sort(ByStreamID(res.pushResponse))
 	return res, nil
 }
 
+func streamEnded(mainSr *serverResponse, streams map[uint32]*serverResponse, sr *serverResponse) bool {
+	delete(streams, sr.streamID)
+	if mainSr.streamID != sr.streamID {
+		mainSr.pushResponse = append(mainSr.pushResponse, sr)
+	}
+	return len(streams) == 0
+}
+
 type serverResponse struct {
 	status            int                  // HTTP status code
 	header            http.Header          // response header fields
 	body              []byte               // response body
+	streamID          uint32               // stream ID in HTTP/2
 	errCode           http2.ErrCode        // error code received in HTTP/2 RST_STREAM or GOAWAY
 	connErr           bool                 // true if HTTP/2 connection error
 	spdyGoAwayErrCode spdy.GoAwayStatus    // status code received in SPDY RST_STREAM
 	spdyRstErrCode    spdy.RstStreamStatus // status code received in SPDY GOAWAY
 	connClose         bool                 // Conection: close is included in response header in HTTP/1 test
+	reqHeader         http.Header          // http request header, currently only sotres pushed request header
+	pushResponse      []*serverResponse    // pushed response
+}
+
+type ByStreamID []*serverResponse
+
+func (b ByStreamID) Len() int {
+	return len(b)
+}
+
+func (b ByStreamID) Swap(i, j int) {
+	b[i], b[j] = b[j], b[i]
+}
+
+func (b ByStreamID) Less(i, j int) bool {
+	return b[i].streamID < b[j].streamID
 }
 
 func cloneHeader(h http.Header) http.Header {

src/HttpServer.cc

@@ -85,7 +85,7 @@ template <typename Array> void append_nv(Stream *stream, const Array &nva) {
       http2::index_header(stream->hdidx, token, i);
     }
     http2::add_header(stream->headers, nv.name, nv.namelen, nv.value,
-                      nv.valuelen, nv.flags & NGHTTP2_NV_FLAG_NO_INDEX);
+                      nv.valuelen, nv.flags & NGHTTP2_NV_FLAG_NO_INDEX, token);
   }
 }
 } // namespace
@@ -1061,7 +1061,7 @@ int on_header_callback(nghttp2_session *session, const nghttp2_frame *frame,
 
   http2::index_header(stream->hdidx, token, stream->headers.size());
   http2::add_header(stream->headers, name, namelen, value, valuelen,
-                    flags & NGHTTP2_NV_FLAG_NO_INDEX);
+                    flags & NGHTTP2_NV_FLAG_NO_INDEX, token);
   return 0;
 }
 } // namespace

src/http2.cc

@@ -165,14 +165,15 @@ void copy_url_component(std::string &dest, const http_parser_url *u, int field,
 
 Headers::value_type to_header(const uint8_t *name, size_t namelen,
                               const uint8_t *value, size_t valuelen,
-                              bool no_index) {
+                              bool no_index, int16_t token) {
   return Header(std::string(reinterpret_cast<const char *>(name), namelen),
                 std::string(reinterpret_cast<const char *>(value), valuelen),
-                no_index);
+                no_index, token);
 }
 
 void add_header(Headers &nva, const uint8_t *name, size_t namelen,
-                const uint8_t *value, size_t valuelen, bool no_index) {
+                const uint8_t *value, size_t valuelen, bool no_index,
+                int16_t token) {
   if (valuelen > 0) {
     size_t i, j;
     for (i = 0; i < valuelen && (value[i] == ' ' || value[i] == '\t'); ++i)
@@ -182,7 +183,7 @@ void add_header(Headers &nva, const uint8_t *name, size_t namelen,
     value += i;
     valuelen -= i + (valuelen - j - 1);
   }
-  nva.push_back(to_header(name, namelen, value, valuelen, no_index));
+  nva.push_back(to_header(name, namelen, value, valuelen, no_index, token));
 }
 
 const Headers::value_type *get_header(const Headers &nva, const char *name) {
@@ -221,7 +222,7 @@ void copy_headers_to_nva(std::vector<nghttp2_nv> &nva, const Headers &headers) {
     if (kv.name.empty() || kv.name[0] == ':') {
       continue;
     }
-    switch (lookup_token(kv.name)) {
+    switch (kv.token) {
     case HD_COOKIE:
     case HD_CONNECTION:
     case HD_HOST:
@@ -247,7 +248,7 @@ void build_http1_headers_from_headers(std::string &hdrs,
     if (kv.name.empty() || kv.name[0] == ':') {
       continue;
     }
-    switch (lookup_token(kv.name)) {
+    switch (kv.token) {
     case HD_CONNECTION:
     case HD_COOKIE:
     case HD_HOST:
@@ -438,6 +439,11 @@ int lookup_token(const uint8_t *name, size_t namelen) {
     break;
   case 4:
     switch (name[namelen - 1]) {
+    case 'k':
+      if (util::streq("lin", name, 3)) {
+        return HD_LINK;
+      }
+      break;
     case 't':
       if (util::streq("hos", name, 3)) {
         return HD_HOST;
@@ -531,6 +537,11 @@ int lookup_token(const uint8_t *name, size_t namelen) {
         return HD_CONNECTION;
       }
       break;
+    case 't':
+      if (util::streq("user-agen", name, 9)) {
+        return HD_USER_AGENT;
+      }
+      break;
     case 'y':
       if (util::streq(":authorit", name, 9)) {
         return HD__AUTHORITY;
@@ -538,6 +549,15 @@ int lookup_token(const uint8_t *name, size_t namelen) {
       break;
     }
     break;
+  case 13:
+    switch (name[namelen - 1]) {
+    case 'l':
+      if (util::streq("cache-contro", name, 12)) {
+        return HD_CACHE_CONTROL;
+      }
+      break;
+    }
+    break;
   case 14:
     switch (name[namelen - 1]) {
     case 'h':
@@ -554,6 +574,16 @@ int lookup_token(const uint8_t *name, size_t namelen) {
     break;
   case 15:
     switch (name[namelen - 1]) {
+    case 'e':
+      if (util::streq("accept-languag", name, 14)) {
+        return HD_ACCEPT_LANGUAGE;
+      }
+      break;
+    case 'g':
+      if (util::streq("accept-encodin", name, 14)) {
+        return HD_ACCEPT_ENCODING;
+      }
+      break;
     case 'r':
       if (util::streq("x-forwarded-fo", name, 14)) {
         return HD_X_FORWARDED_FOR;
@@ -597,18 +627,7 @@ void init_hdidx(HeaderIndex &hdidx) {
   std::fill(std::begin(hdidx), std::end(hdidx), -1);
 }
 
-void index_headers(HeaderIndex &hdidx, const Headers &headers) {
+void index_header(HeaderIndex &hdidx, int16_t token, size_t idx) {
-  for (size_t i = 0; i < headers.size(); ++i) {
-    auto &kv = headers[i];
-    auto token = lookup_token(
-        reinterpret_cast<const uint8_t *>(kv.name.c_str()), kv.name.size());
-    if (token >= 0) {
-      http2::index_header(hdidx, token, i);
-    }
-  }
-}
-
-void index_header(HeaderIndex &hdidx, int token, size_t idx) {
   if (token == -1) {
     return;
   }
@@ -616,7 +635,8 @@ void index_header(HeaderIndex &hdidx, int token, size_t idx) {
   hdidx[token] = idx;
 }
 
-bool check_http2_request_pseudo_header(const HeaderIndex &hdidx, int token) {
+bool check_http2_request_pseudo_header(const HeaderIndex &hdidx,
+                                       int16_t token) {
   switch (token) {
   case HD__AUTHORITY:
   case HD__METHOD:
@@ -628,7 +648,8 @@ bool check_http2_request_pseudo_header(const HeaderIndex &hdidx, int token) {
   }
 }
 
-bool check_http2_response_pseudo_header(const HeaderIndex &hdidx, int token) {
+bool check_http2_response_pseudo_header(const HeaderIndex &hdidx,
+                                        int16_t token) {
   switch (token) {
   case HD__STATUS:
     return hdidx[token] == -1;
@@ -637,7 +658,7 @@ bool check_http2_response_pseudo_header(const HeaderIndex &hdidx, int token) {
   }
 }
 
-bool http2_header_allowed(int token) {
+bool http2_header_allowed(int16_t token) {
   switch (token) {
   case HD_CONNECTION:
   case HD_KEEP_ALIVE:
@@ -659,7 +680,7 @@ bool http2_mandatory_request_headers_presence(const HeaderIndex &hdidx) {
   return true;
 }
 
-const Headers::value_type *get_header(const HeaderIndex &hdidx, int token,
+const Headers::value_type *get_header(const HeaderIndex &hdidx, int16_t token,
                                       const Headers &nva) {
   auto i = hdidx[token];
   if (i == -1) {
@@ -668,6 +689,336 @@ const Headers::value_type *get_header(const HeaderIndex &hdidx, int token,
   return &nva[i];
 }
 
+namespace {
+template <typename InputIt> InputIt skip_lws(InputIt first, InputIt last) {
+  for (; first != last; ++first) {
+    switch (*first) {
+    case ' ':
+    case '\t':
+      continue;
+    default:
+      return first;
+    }
+  }
+  return first;
+}
+} // namespace
+
+namespace {
+template <typename InputIt>
+InputIt skip_to_next_field(InputIt first, InputIt last) {
+  for (; first != last; ++first) {
+    switch (*first) {
+    case ' ':
+    case '\t':
+    case ',':
+      continue;
+    default:
+      return first;
+    }
+  }
+  return first;
+}
+} // namespace
+
+namespace {
+std::pair<LinkHeader, const char *>
+parse_next_link_header_once(const char *first, const char *last) {
+  first = skip_to_next_field(first, last);
+  if (first == last || *first != '<') {
+    return {{{0, 0}}, last};
+  }
+  auto url_first = ++first;
+  first = std::find(first, last, '>');
+  if (first == last) {
+    return {{{0, 0}}, first};
+  }
+  auto url_last = first++;
+  if (first == last) {
+    return {{{0, 0}}, first};
+  }
+  // we expect ';' or ',' here
+  switch (*first) {
+  case ',':
+    return {{{0, 0}}, ++first};
+  case ';':
+    ++first;
+    break;
+  default:
+    return {{{0, 0}}, last};
+  }
+
+  auto ok = false;
+  for (;;) {
+    first = skip_lws(first, last);
+    if (first == last) {
+      return {{{0, 0}}, first};
+    }
+    // we expect link-param
+
+    // we are only interested in rel=preload parameter.  Others are
+    // simply skipped.
+    static const char PL[] = "rel=preload";
+    static const size_t PLLEN = sizeof(PL) - 1;
+    if (first + PLLEN == last) {
+      if (std::equal(PL, PL + PLLEN, first)) {
+        ok = true;
+        // this is the end of sequence
+        return {{{url_first, url_last}}, last};
+      }
+    } else if (first + PLLEN + 1 <= last) {
+      switch (*(first + PLLEN)) {
+      case ',':
+        if (!std::equal(PL, PL + PLLEN, first)) {
+          break;
+        }
+        ok = true;
+        // skip including ','
+        first += PLLEN + 1;
+        return {{{url_first, url_last}}, first};
+      case ';':
+        if (!std::equal(PL, PL + PLLEN, first)) {
+          break;
+        }
+        ok = true;
+        // skip including ';'
+        first += PLLEN + 1;
+        // continue parse next link-param
+        continue;
+      }
+    }
+    auto param_first = first;
+    for (; first != last;) {
+      if (util::in_attr_char(*first)) {
+        ++first;
+        continue;
+      }
+      // '*' is only allowed at the end of parameter name and must be
+      // followed by '='
+      if (last - first >= 2 && first != param_first) {
+        if (*first == '*' && *(first + 1) == '=') {
+          ++first;
+          break;
+        }
+      }
+      if (*first == '=' || *first == ';' || *first == ',') {
+        break;
+      }
+      return {{{0, 0}}, last};
+    }
+    if (param_first == first) {
+      // empty parmname
+      return {{{0, 0}}, last};
+    }
+    // link-param without value is acceptable (see link-extension) if
+    // it is not followed by '='
+    if (first == last || *first == ',') {
+      goto almost_done;
+    }
+    if (*first == ';') {
+      ++first;
+      // parse next link-param
+      continue;
+    }
+    // now parsing lin-param value
+    assert(*first == '=');
+    ++first;
+    if (first == last) {
+      // empty value is not acceptable
+      return {{{0, 0}}, first};
+    }
+    if (*first == '"') {
+      // quoted-string
+      first = std::find(first + 1, last, '"');
+      if (first == last) {
+        return {{{0, 0}}, first};
+      }
+      ++first;
+      if (first == last || *first == ',') {
+        goto almost_done;
+      }
+      if (*first == ';') {
+        ++first;
+        // parse next link-param
+        continue;
+      }
+      return {{{0, 0}}, last};
+    }
+    // not quoted-string, skip to next ',' or ';'
+    if (*first == ',' || *first == ';') {
+      // empty value
+      return {{{0, 0}}, last};
+    }
+    for (; first != last; ++first) {
+      if (*first == ',' || *first == ';') {
+        break;
+      }
+    }
+    if (first == last || *first == ',') {
+      goto almost_done;
+    }
+    assert(*first == ';');
+    ++first;
+    // parse next link-param
+  }
+
+almost_done:
+  assert(first == last || *first == ',');
+
+  if (*first == ',') {
+    ++first;
+  }
+  if (ok) {
+    return {{{url_first, url_last}}, first};
+  }
+  return {{{0, 0}}, first};
+}
+} // namespace
+
+std::vector<LinkHeader> parse_link_header(const char *src, size_t len) {
+  auto first = src;
+  auto last = src + len;
+  std::vector<LinkHeader> res;
+  for (; first != last;) {
+    auto rv = parse_next_link_header_once(first, last);
+    first = rv.second;
+    if (rv.first.uri.first != 0 || rv.first.uri.second != 0) {
+      res.push_back(rv.first);
+    }
+  }
+  return res;
+}
+
+namespace {
+void eat_file(std::string &path) {
+  if (path.empty()) {
+    path = "/";
+    return;
+  }
+  auto p = path.size() - 1;
+  if (path[p] == '/') {
+    return;
+  }
+  p = path.rfind('/', p);
+  if (p == std::string::npos) {
+    // this should not happend in normal case, where we expect path
+    // starts with '/'
+    path = "/";
+    return;
+  }
+  path.erase(std::begin(path) + p + 1, std::end(path));
+}
+} // namespace
+
+namespace {
+void eat_dir(std::string &path) {
+  if (path.empty()) {
+    path = "/";
+    return;
+  }
+  auto p = path.size() - 1;
+  if (path[p] != '/') {
+    p = path.rfind('/', p);
+    if (p == std::string::npos) {
+      // this should not happend in normal case, where we expect path
+      // starts with '/'
+      path = "/";
+      return;
+    }
+  }
+  if (path[p] == '/') {
+    if (p == 0) {
+      return;
+    }
+    --p;
+  }
+  p = path.rfind('/', p);
+  if (p == std::string::npos) {
+    // this should not happend in normal case, where we expect path
+    // starts with '/'
+    path = "/";
+    return;
+  }
+  path.erase(std::begin(path) + p + 1, std::end(path));
+}
+} // namespace
+
+std::string path_join(const char *base_path, size_t base_pathlen,
+                      const char *base_query, size_t base_querylen,
+                      const char *rel_path, size_t rel_pathlen,
+                      const char *rel_query, size_t rel_querylen) {
+  std::string res;
+  if (rel_pathlen == 0) {
+    if (base_pathlen == 0) {
+      res = "/";
+    } else {
+      res.assign(base_path, base_pathlen);
+    }
+    if (rel_querylen == 0) {
+      if (base_querylen) {
+        res += "?";
+        res.append(base_query, base_querylen);
+      }
+      return res;
+    }
+    res += "?";
+    res.append(rel_query, rel_querylen);
+    return res;
+  }
+
+  auto first = rel_path;
+  auto last = rel_path + rel_pathlen;
+
+  if (rel_path[0] == '/') {
+    res = "/";
+    ++first;
+  } else if (base_pathlen == 0) {
+    res = "/";
+  } else {
+    res.assign(base_path, base_pathlen);
+  }
+
+  for (; first != last;) {
+    if (*first == '.') {
+      if (first + 1 == last) {
+        break;
+      }
+      if (*(first + 1) == '/') {
+        first += 2;
+        continue;
+      }
+      if (*(first + 1) == '.') {
+        if (first + 2 == last) {
+          eat_dir(res);
+          break;
+        }
+        if (*(first + 2) == '/') {
+          eat_dir(res);
+          first += 3;
+          continue;
+        }
+      }
+    }
+    if (res.back() != '/') {
+      eat_file(res);
+    }
+    auto slash = std::find(first, last, '/');
+    if (slash == last) {
+      res.append(first, last);
+      break;
+    }
+    res.append(first, slash + 1);
+    first = slash + 1;
+    for (; first != last && *first == '/'; ++first)
+      ;
+  }
+  if (rel_querylen) {
+    res += "?";
+    res.append(rel_query, rel_querylen);
+  }
+  return res;
+}
+
 } // namespace http2
 
 } // namespace nghttp2

src/http2.h

@@ -40,10 +40,12 @@
 namespace nghttp2 {
 
 struct Header {
-  Header(std::string name, std::string value, bool no_index = false)
+  Header(std::string name, std::string value, bool no_index = false,
-      : name(std::move(name)), value(std::move(value)), no_index(no_index) {}
+         int16_t token = -1)
+      : name(std::move(name)), value(std::move(value)), token(token),
+        no_index(no_index) {}
 
-  Header() : no_index(false) {}
+  Header() : token(-1), no_index(false) {}
 
   bool operator==(const Header &other) const {
     return name == other.name && value == other.value;
@@ -55,6 +57,7 @@ struct Header {
 
   std::string name;
   std::string value;
+  int16_t token;
   bool no_index;
 };
 
@@ -77,13 +80,14 @@ void copy_url_component(std::string &dest, const http_parser_url *u, int field,
 
 Headers::value_type to_header(const uint8_t *name, size_t namelen,
                               const uint8_t *value, size_t valuelen,
-                              bool no_index);
+                              bool no_index, int16_t token);
 
 // Add name/value pairs to |nva|.  If |no_index| is true, this
 // name/value pair won't be indexed when it is forwarded to the next
 // hop.  This function strips white spaces around |value|.
 void add_header(Headers &nva, const uint8_t *name, size_t namelen,
-                const uint8_t *value, size_t valuelen, bool no_index);
+                const uint8_t *value, size_t valuelen, bool no_index,
+                int16_t token);
 
 // Returns pointer to the entry in |nva| which has name |name|.  If
 // more than one entries which have the name |name|, last occurrence
@@ -125,14 +129,16 @@ nghttp2_nv make_nv_ls(const char (&name)[N], const std::string &value) {
           NGHTTP2_NV_FLAG_NONE};
 }
 
-// Appends headers in |headers| to |nv|. Certain headers, including
+// Appends headers in |headers| to |nv|.  |headers| must be indexed
-// disallowed headers in HTTP/2 spec and headers which require
+// before this call (its element's token field is assigned).  Certain
-// special handling (i.e. via), are not copied.
+// headers, including disallowed headers in HTTP/2 spec and headers
+// which require special handling (i.e. via), are not copied.
 void copy_headers_to_nva(std::vector<nghttp2_nv> &nva, const Headers &headers);
 
 // Appends HTTP/1.1 style header lines to |hdrs| from headers in
-// |headers|. Certain headers, which requires special handling
+// |headers|.  |headers| must be indexed before this call (its
-// (i.e. via and cookie), are not appended.
+// element's token field is assigned).  Certain headers, which
+// requires special handling (i.e. via and cookie), are not appended.
 void build_http1_headers_from_headers(std::string &hdrs,
                                       const Headers &headers);
 
@@ -189,7 +195,10 @@ enum {
   HD__PATH,
   HD__SCHEME,
   HD__STATUS,
+  HD_ACCEPT_ENCODING,
+  HD_ACCEPT_LANGUAGE,
   HD_ALT_SVC,
+  HD_CACHE_CONTROL,
   HD_CONNECTION,
   HD_CONTENT_LENGTH,
   HD_COOKIE,
@@ -198,6 +207,7 @@ enum {
   HD_HTTP2_SETTINGS,
   HD_IF_MODIFIED_SINCE,
   HD_KEEP_ALIVE,
+  HD_LINK,
   HD_LOCATION,
   HD_PROXY_CONNECTION,
   HD_SERVER,
@@ -205,13 +215,14 @@ enum {
   HD_TRAILER,
   HD_TRANSFER_ENCODING,
   HD_UPGRADE,
+  HD_USER_AGENT,
   HD_VIA,
   HD_X_FORWARDED_FOR,
   HD_X_FORWARDED_PROTO,
   HD_MAXIDX,
 };
 
-using HeaderIndex = std::array<int, HD_MAXIDX>;
+using HeaderIndex = std::array<int16_t, HD_MAXIDX>;
 
 // Looks up header token for header name |name| of length |namelen|.
 // Only headers we are interested in are tokenized.  If header name
@@ -223,30 +234,51 @@ int lookup_token(const std::string &name);
 // array containing at least HD_MAXIDX elements.
 void init_hdidx(HeaderIndex &hdidx);
 // Indexes header |token| using index |idx|.
-void index_header(HeaderIndex &hdidx, int token, size_t idx);
+void index_header(HeaderIndex &hdidx, int16_t token, size_t idx);
-// Iterates |headers| and for each element, call index_header.
-void index_headers(HeaderIndex &hdidx, const Headers &headers);
 
 // Returns true if HTTP/2 request pseudo header |token| is not indexed
 // yet and not -1.
-bool check_http2_request_pseudo_header(const HeaderIndex &hdidx, int token);
+bool check_http2_request_pseudo_header(const HeaderIndex &hdidx, int16_t token);
 
 // Returns true if HTTP/2 response pseudo header |token| is not
 // indexed yet and not -1.
-bool check_http2_response_pseudo_header(const HeaderIndex &hdidx, int token);
+bool check_http2_response_pseudo_header(const HeaderIndex &hdidx,
+                                        int16_t token);
 
 // Returns true if header field denoted by |token| is allowed for
 // HTTP/2.
-bool http2_header_allowed(int token);
+bool http2_header_allowed(int16_t token);
 
 // Returns true that |hdidx| contains mandatory HTTP/2 request
 // headers.
 bool http2_mandatory_request_headers_presence(const HeaderIndex &hdidx);
 
 // Returns header denoted by |token| using index |hdidx|.
-const Headers::value_type *get_header(const HeaderIndex &hdidx, int token,
+const Headers::value_type *get_header(const HeaderIndex &hdidx, int16_t token,
                                       const Headers &nva);
 
+struct LinkHeader {
+  // The region of URI is [uri.first, uri.second).
+  std::pair<const char *, const char *> uri;
+};
+
+// Returns next URI-reference in Link header field value |src| of
+// length |len|.  If no URI-reference found after searching all input,
+// returned uri field is empty.  This imply that empty URI-reference
+// is ignored during parsing.
+std::vector<LinkHeader> parse_link_header(const char *src, size_t len);
+
+// Constructs path by combining base path |base_path| of length
+// |base_pathlen| with another path |rel_path| of length
+// |rel_pathlen|.  The base path and another path can have optional
+// query component.  This function assumes |base_path| is
+// cannibalized.  In other words, it does not contain ".." or "." path
+// components and starts with "/" if it is not empty.
+std::string path_join(const char *base_path, size_t base_pathlen,
+                      const char *base_query, size_t base_querylen,
+                      const char *rel_path, size_t rel_pathlen,
+                      const char *rel_query, size_t rel_querylen);
+
 } // namespace http2
 
 } // namespace nghttp2

src/http2_test.cc

@@ -58,46 +58,52 @@ void test_http2_add_header(void) {
   auto nva = Headers();
 
   http2::add_header(nva, (const uint8_t *)"alpha", 5, (const uint8_t *)"123", 3,
-                    false);
+                    false, -1);
   CU_ASSERT(Headers::value_type("alpha", "123") == nva[0]);
   CU_ASSERT(!nva[0].no_index);
 
   nva.clear();
 
   http2::add_header(nva, (const uint8_t *)"alpha", 5, (const uint8_t *)"", 0,
-                    true);
+                    true, -1);
   CU_ASSERT(Headers::value_type("alpha", "") == nva[0]);
   CU_ASSERT(nva[0].no_index);
 
   nva.clear();
 
   http2::add_header(nva, (const uint8_t *)"a", 1, (const uint8_t *)" b", 2,
-                    false);
+                    false, -1);
   CU_ASSERT(Headers::value_type("a", "b") == nva[0]);
 
   nva.clear();
 
   http2::add_header(nva, (const uint8_t *)"a", 1, (const uint8_t *)"b ", 2,
-                    false);
+                    false, -1);
   CU_ASSERT(Headers::value_type("a", "b") == nva[0]);
 
   nva.clear();
 
   http2::add_header(nva, (const uint8_t *)"a", 1, (const uint8_t *)"  b  ", 5,
-                    false);
+                    false, -1);
   CU_ASSERT(Headers::value_type("a", "b") == nva[0]);
 
   nva.clear();
 
   http2::add_header(nva, (const uint8_t *)"a", 1, (const uint8_t *)"  bravo  ",
-                    9, false);
+                    9, false, -1);
   CU_ASSERT(Headers::value_type("a", "bravo") == nva[0]);
 
   nva.clear();
 
   http2::add_header(nva, (const uint8_t *)"a", 1, (const uint8_t *)"    ", 4,
-                    false);
+                    false, -1);
   CU_ASSERT(Headers::value_type("a", "") == nva[0]);
+
+  nva.clear();
+
+  http2::add_header(nva, (const uint8_t *)"te", 2, (const uint8_t *)"trailers",
+                    8, false, http2::HD_TE);
+  CU_ASSERT(http2::HD_TE == nva[0].token);
 }
 
 void test_http2_get_header(void) {
@@ -128,19 +134,20 @@ void test_http2_get_header(void) {
 }
 
 namespace {
-auto headers = Headers{{"alpha", "0", true},
+auto headers =
-                       {"bravo", "1"},
+    Headers{{"alpha", "0", true},
-                       {"connection", "2"},
+            {"bravo", "1"},
-                       {"connection", "3"},
+            {"connection", "2", false, http2::HD_CONNECTION},
-                       {"delta", "4"},
+            {"connection", "3", false, http2::HD_CONNECTION},
-                       {"expect", "5"},
+            {"delta", "4"},
-                       {"foxtrot", "6"},
+            {"expect", "5"},
-                       {"tango", "7"},
+            {"foxtrot", "6"},
-                       {"te", "8"},
+            {"tango", "7"},
-                       {"te", "9"},
+            {"te", "8", false, http2::HD_TE},
-                       {"x-forwarded-proto", "10"},
+            {"te", "9", false, http2::HD_TE},
-                       {"x-forwarded-proto", "11"},
+            {"x-forwarded-proto", "10", false, http2::HD_X_FORWARDED_FOR},
-                       {"zulu", "12"}};
+            {"x-forwarded-proto", "11", false, http2::HD_X_FORWARDED_FOR},
+            {"zulu", "12"}};
 } // namespace
 
 void test_http2_copy_headers_to_nva(void) {
@@ -290,4 +297,366 @@ void test_http2_mandatory_request_headers_presence(void) {
   CU_ASSERT(http2::http2_mandatory_request_headers_presence(hdidx));
 }
 
+void test_http2_parse_link_header(void) {
+  {
+    // only URI appears; we don't extract URI unless it bears rel=preload
+    const char s[] = "<url>";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // URI url should be extracted
+    const char s[] = "<url>; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // With extra link-param.  URI url should be extracted
+    const char s[] = "<url>; rel=preload; as=file";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // With extra link-param.  URI url should be extracted
+    const char s[] = "<url>; as=file; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // With extra link-param and quote-string.  URI url should be
+    // extracted
+    const char s[] = R"(<url>; rel=preload; title="foo,bar")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // With extra link-param and quote-string.  URI url should be
+    // extracted
+    const char s[] = R"(<url>; title="foo,bar"; rel=preload)";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // ',' after quote-string
+    const char s[] = R"(<url>; title="foo,bar", <url>; rel=preload)";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[25], &s[28]) == res[0].uri);
+  }
+  {
+    // Only first URI should be extracted.
+    const char s[] = "<url>; rel=preload, <url>";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // Both have rel=preload, so both urls should be extracted
+    const char s[] = "<url>; rel=preload, <url>; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(2 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+    CU_ASSERT(std::make_pair(&s[21], &s[24]) == res[1].uri);
+  }
+  {
+    // Second URI uri should be extracted.
+    const char s[] = "<url>, <url>;rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[8], &s[11]) == res[0].uri);
+  }
+  {
+    // Error if input ends with ';'
+    const char s[] = "<url>;rel=preload;";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // OK if input ends with ','
+    const char s[] = "<url>;rel=preload,";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // Multiple repeated ','s between fields is OK
+    const char s[] = "<url>,,,<url>;rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[9], &s[12]) == res[0].uri);
+  }
+  {
+    // Error if url is not enclosed by <>
+    const char s[] = "url>;rel=preload;";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // Error if url is not enclosed by <>
+    const char s[] = "<url;rel=preload;";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // Empty parameter value is not allowed
+    const char s[] = "<url>;rel=preload; as=";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // Empty parameter value is not allowed
+    const char s[] = "<url>;as=;rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // Empty parameter value is not allowed
+    const char s[] = "<url>;as=, <url>;rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // Empty parameter name is not allowed
+    const char s[] = "<url>; =file; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // Without whitespaces
+    const char s[] = "<url>;as=file;rel=preload,<url>;rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(2 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+    CU_ASSERT(std::make_pair(&s[27], &s[30]) == res[1].uri);
+  }
+  {
+    // link-extension may have no value
+    const char s[] = "<url>; as; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // ext-name-star
+    const char s[] = "<url>; foo*=bar; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // '*' is not allowed expect for trailing one
+    const char s[] = "<url>; *=bar; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // '*' is not allowed expect for trailing one
+    const char s[] = "<url>; foo*bar=buzz; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // ext-name-star must be followed by '='
+    const char s[] = "<url>; foo*; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // '>' is not followed by ';'
+    const char s[] = "<url> rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // Starting with whitespace is no problem.
+    const char s[] = "  <url>; rel=preload";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[3], &s[6]) == res[0].uri);
+  }
+  {
+    // preload is a prefix of bogus rel parameter value
+    const char s[] = "<url>; rel=preloadx";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+}
+
+void test_http2_path_join(void) {
+  {
+    const char base[] = "/";
+    const char rel[] = "/";
+    CU_ASSERT("/" == http2::path_join(base, sizeof(base) - 1, nullptr, 0, rel,
+                                      sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    const char base[] = "/";
+    const char rel[] = "/alpha";
+    CU_ASSERT("/alpha" == http2::path_join(base, sizeof(base) - 1, nullptr, 0,
+                                           rel, sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // rel ends with trailing '/'
+    const char base[] = "/";
+    const char rel[] = "/alpha/";
+    CU_ASSERT("/alpha/" == http2::path_join(base, sizeof(base) - 1, nullptr, 0,
+                                            rel, sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // rel contains multiple components
+    const char base[] = "/";
+    const char rel[] = "/alpha/bravo";
+    CU_ASSERT("/alpha/bravo" == http2::path_join(base, sizeof(base) - 1,
+                                                 nullptr, 0, rel,
+                                                 sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // rel is relative
+    const char base[] = "/";
+    const char rel[] = "alpha/bravo";
+    CU_ASSERT("/alpha/bravo" == http2::path_join(base, sizeof(base) - 1,
+                                                 nullptr, 0, rel,
+                                                 sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // rel is relative and base ends without /, which means it refers
+    // to file.
+    const char base[] = "/alpha";
+    const char rel[] = "bravo/charlie";
+    CU_ASSERT("/bravo/charlie" ==
+              http2::path_join(base, sizeof(base) - 1, nullptr, 0, rel,
+                               sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // rel contains repeated '/'s
+    const char base[] = "/";
+    const char rel[] = "/alpha/////bravo/////";
+    CU_ASSERT("/alpha/bravo/" == http2::path_join(base, sizeof(base) - 1,
+                                                  nullptr, 0, rel,
+                                                  sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // base ends with '/', so '..' eats 'bravo'
+    const char base[] = "/alpha/bravo/";
+    const char rel[] = "../charlie/delta";
+    CU_ASSERT("/alpha/charlie/delta" ==
+              http2::path_join(base, sizeof(base) - 1, nullptr, 0, rel,
+                               sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // base does not end with '/', so '..' eats 'alpha/bravo'
+    const char base[] = "/alpha/bravo";
+    const char rel[] = "../charlie";
+    CU_ASSERT("/charlie" == http2::path_join(base, sizeof(base) - 1, nullptr, 0,
+                                             rel, sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // 'charlie' is eaten by following '..'
+    const char base[] = "/alpha/bravo/";
+    const char rel[] = "../charlie/../delta";
+    CU_ASSERT("/alpha/delta" == http2::path_join(base, sizeof(base) - 1,
+                                                 nullptr, 0, rel,
+                                                 sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // excessive '..' results in '/'
+    const char base[] = "/alpha/bravo/";
+    const char rel[] = "../../../";
+    CU_ASSERT("/" == http2::path_join(base, sizeof(base) - 1, nullptr, 0, rel,
+                                      sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // excessive '..'  and  path component
+    const char base[] = "/alpha/bravo/";
+    const char rel[] = "../../../charlie";
+    CU_ASSERT("/charlie" == http2::path_join(base, sizeof(base) - 1, nullptr, 0,
+                                             rel, sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // rel ends with '..'
+    const char base[] = "/alpha/bravo/";
+    const char rel[] = "charlie/..";
+    CU_ASSERT("/alpha/bravo/" == http2::path_join(base, sizeof(base) - 1,
+                                                  nullptr, 0, rel,
+                                                  sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // base empty and rel contains '..'
+    const char base[] = "";
+    const char rel[] = "charlie/..";
+    CU_ASSERT("/" == http2::path_join(base, sizeof(base) - 1, nullptr, 0, rel,
+                                      sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // '.' is ignored
+    const char base[] = "/";
+    const char rel[] = "charlie/././././delta";
+    CU_ASSERT("/charlie/delta" ==
+              http2::path_join(base, sizeof(base) - 1, nullptr, 0, rel,
+                               sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // trailing '.' is ignored
+    const char base[] = "/";
+    const char rel[] = "charlie/.";
+    CU_ASSERT("/charlie/" == http2::path_join(base, sizeof(base) - 1, nullptr,
+                                              0, rel, sizeof(rel) - 1, nullptr,
+                                              0));
+  }
+  {
+    // query
+    const char base[] = "/";
+    const char rel[] = "/";
+    const char relq[] = "q";
+    CU_ASSERT("/?q" == http2::path_join(base, sizeof(base) - 1, nullptr, 0, rel,
+                                        sizeof(rel) - 1, relq,
+                                        sizeof(relq) - 1));
+  }
+  {
+    // empty rel and query
+    const char base[] = "/alpha";
+    const char rel[] = "";
+    const char relq[] = "q";
+    CU_ASSERT("/alpha?q" == http2::path_join(base, sizeof(base) - 1, nullptr, 0,
+                                             rel, sizeof(rel) - 1, relq,
+                                             sizeof(relq) - 1));
+  }
+  {
+    // both rel and query are empty
+    const char base[] = "/alpha";
+    const char baseq[] = "r";
+    const char rel[] = "";
+    const char relq[] = "";
+    CU_ASSERT("/alpha?r" ==
+              http2::path_join(base, sizeof(base) - 1, baseq, sizeof(baseq) - 1,
+                               rel, sizeof(rel) - 1, relq, sizeof(relq) - 1));
+  }
+  {
+    // empty base
+    const char base[] = "";
+    const char rel[] = "/alpha";
+    CU_ASSERT("/alpha" == http2::path_join(base, sizeof(base) - 1, nullptr, 0,
+                                           rel, sizeof(rel) - 1, nullptr, 0));
+  }
+  {
+    // everything is empty
+    CU_ASSERT("/" ==
+              http2::path_join(nullptr, 0, nullptr, 0, nullptr, 0, nullptr, 0));
+  }
+  {
+    // only baseq is not empty
+    const char base[] = "";
+    const char baseq[] = "r";
+    const char rel[] = "";
+    CU_ASSERT("/?r" == http2::path_join(base, sizeof(base) - 1, baseq,
+                                        sizeof(baseq) - 1, rel, sizeof(rel) - 1,
+                                        nullptr, 0));
+  }
+}
+
 } // namespace shrpx

src/http2_test.h

@@ -39,6 +39,8 @@ void test_http2_lookup_token(void);
 void test_http2_check_http2_pseudo_header(void);
 void test_http2_http2_header_allowed(void);
 void test_http2_mandatory_request_headers_presence(void);
+void test_http2_parse_link_header(void);
+void test_http2_path_join(void);
 
 } // namespace shrpx
 

src/nghttp.cc

@@ -250,7 +250,7 @@ bool Request::is_ipv6_literal_addr() const {
   }
 }
 
-bool Request::response_pseudo_header_allowed(int token) const {
+bool Request::response_pseudo_header_allowed(int16_t token) const {
   if (!res_nva.empty() && res_nva.back().name.c_str()[0] != ':') {
     return false;
   }
@@ -262,7 +262,7 @@ bool Request::response_pseudo_header_allowed(int token) const {
   }
 }
 
-bool Request::push_request_pseudo_header_allowed(int token) const {
+bool Request::push_request_pseudo_header_allowed(int16_t token) const {
   if (!req_nva.empty() && req_nva.back().name.c_str()[0] != ':') {
     return false;
   }
@@ -277,7 +277,7 @@ bool Request::push_request_pseudo_header_allowed(int token) const {
   }
 }
 
-Headers::value_type *Request::get_res_header(int token) {
+Headers::value_type *Request::get_res_header(int16_t token) {
   auto idx = res_hdidx[token];
   if (idx == -1) {
     return nullptr;
@@ -285,7 +285,7 @@ Headers::value_type *Request::get_res_header(int token) {
   return &res_nva[idx];
 }
 
-Headers::value_type *Request::get_req_header(int token) {
+Headers::value_type *Request::get_req_header(int16_t token) {
   auto idx = req_hdidx[token];
   if (idx == -1) {
     return nullptr;
@@ -1688,7 +1688,7 @@ int on_header_callback(nghttp2_session *session, const nghttp2_frame *frame,
 
     http2::index_header(req->res_hdidx, token, req->res_nva.size());
     http2::add_header(req->res_nva, name, namelen, value, valuelen,
-                      flags & NGHTTP2_NV_FLAG_NO_INDEX);
+                      flags & NGHTTP2_NV_FLAG_NO_INDEX, token);
     break;
   }
   case NGHTTP2_PUSH_PROMISE: {
@@ -1712,7 +1712,7 @@ int on_header_callback(nghttp2_session *session, const nghttp2_frame *frame,
 
     http2::index_header(req->req_hdidx, token, req->req_nva.size());
     http2::add_header(req->req_nva, name, namelen, value, valuelen,
-                      flags & NGHTTP2_NV_FLAG_NO_INDEX);
+                      flags & NGHTTP2_NV_FLAG_NO_INDEX, token);
     break;
   }
   }

src/nghttp.h

@@ -122,11 +122,11 @@ struct Request {
 
   bool is_ipv6_literal_addr() const;
 
-  bool response_pseudo_header_allowed(int token) const;
+  bool response_pseudo_header_allowed(int16_t token) const;
-  bool push_request_pseudo_header_allowed(int token) const;
+  bool push_request_pseudo_header_allowed(int16_t token) const;
 
-  Headers::value_type *get_res_header(int token);
+  Headers::value_type *get_res_header(int16_t token);
-  Headers::value_type *get_req_header(int token);
+  Headers::value_type *get_req_header(int16_t token);
 
   void record_request_time();
   void record_response_time();

src/shrpx-unittest.cc

@@ -93,6 +93,9 @@ int main(int argc, char *argv[]) {
                    shrpx::test_http2_http2_header_allowed) ||
       !CU_add_test(pSuite, "http2_mandatory_request_headers_presence",
                    shrpx::test_http2_mandatory_request_headers_presence) ||
+      !CU_add_test(pSuite, "http2_parse_link_header",
+                   shrpx::test_http2_parse_link_header) ||
+      !CU_add_test(pSuite, "http2_path_join", shrpx::test_http2_path_join) ||
       !CU_add_test(pSuite, "downstream_index_request_headers",
                    shrpx::test_downstream_index_request_headers) ||
       !CU_add_test(pSuite, "downstream_index_response_headers",

src/shrpx.cc

@@ -782,6 +782,7 @@ void fill_default_config() {
   mod_config()->tls_ctx_per_worker = false;
   mod_config()->downstream_request_buffer_size = 16 * 1024;
   mod_config()->downstream_response_buffer_size = 16 * 1024;
+  mod_config()->no_server_push = false;
 }
 } // namespace
 
@@ -1087,6 +1088,10 @@ HTTP/2 and SPDY:
               padding.  Specify 0 to  disable padding.  This option is
               meant for debugging purpose  and not intended to enhance
               protocol security.
+  --no-server-push
+              Disable  HTTP/2  server  push.    Server  push  is  only
+              supported  by default  mode and  HTTP/2 frontend.   SPDY
+              frontend does not support server push.
 
 Mode:
   (default mode)
@@ -1345,6 +1350,7 @@ int main(int argc, char **argv) {
         {"backend-response-buffer", required_argument, &flag, 71},
         {"backend-request-buffer", required_argument, &flag, 72},
         {"no-host-rewrite", no_argument, &flag, 73},
+        {"no-server-push", no_argument, &flag, 74},
         {nullptr, 0, nullptr, 0}};
 
     int option_index = 0;
@@ -1678,6 +1684,10 @@ int main(int argc, char **argv) {
         // --no-host-rewrite
         cmdcfgs.emplace_back(SHRPX_OPT_NO_HOST_REWRITE, "yes");
         break;
+      case 74:
+        // --no-server-push
+        cmdcfgs.emplace_back(SHRPX_OPT_NO_SERVER_PUSH, "yes");
+        break;
       default:
         break;
       }

src/shrpx_config.cc

@@ -145,6 +145,7 @@ const char SHRPX_OPT_RLIMIT_NOFILE[] = "rlimit-nofile";
 const char SHRPX_OPT_TLS_CTX_PER_WORKER[] = "tls-ctx-per-worker";
 const char SHRPX_OPT_BACKEND_REQUEST_BUFFER[] = "backend-request-buffer";
 const char SHRPX_OPT_BACKEND_RESPONSE_BUFFER[] = "backend-response-buffer";
+const char SHRPX_OPT_NO_SERVER_PUSH[] = "no-server-push";
 
 namespace {
 Config *config = nullptr;
@@ -1165,6 +1166,12 @@ int parse_config(const char *opt, const char *optarg) {
     return 0;
   }
 
+  if (util::strieq(opt, SHRPX_OPT_NO_SERVER_PUSH)) {
+    mod_config()->no_server_push = util::strieq(optarg, "yes");
+
+    return 0;
+  }
+
   if (util::strieq(opt, "conf")) {
     LOG(WARN) << "conf: ignored";
 

src/shrpx_config.h

@@ -132,6 +132,7 @@ extern const char SHRPX_OPT_RLIMIT_NOFILE[];
 extern const char SHRPX_OPT_TLS_CTX_PER_WORKER[];
 extern const char SHRPX_OPT_BACKEND_REQUEST_BUFFER[];
 extern const char SHRPX_OPT_BACKEND_RESPONSE_BUFFER[];
+extern const char SHRPX_OPT_NO_SERVER_PUSH[];
 
 union sockaddr_union {
   sockaddr_storage storage;
@@ -304,6 +305,7 @@ struct Config {
   bool no_host_rewrite;
   bool auto_tls_ticket_key;
   bool tls_ctx_per_worker;
+  bool no_server_push;
 };
 
 const Config *get_config();

src/shrpx_downstream.cc

@@ -300,6 +300,7 @@ int index_headers(http2::HeaderIndex &hdidx, Headers &headers,
       continue;
     }
 
+    kv.token = token;
     http2::index_header(hdidx, token, i);
 
     if (token == http2::HD_CONTENT_LENGTH) {
@@ -322,7 +323,7 @@ int Downstream::index_request_headers() {
                        request_content_length_);
 }
 
-const Headers::value_type *Downstream::get_request_header(int token) const {
+const Headers::value_type *Downstream::get_request_header(int16_t token) const {
   return http2::get_header(request_hdidx_, token, request_headers_);
 }
 
@@ -346,10 +347,11 @@ void Downstream::set_last_request_header_value(std::string value) {
 
 void Downstream::add_request_header(const uint8_t *name, size_t namelen,
                                     const uint8_t *value, size_t valuelen,
-                                    bool no_index, int token) {
+                                    bool no_index, int16_t token) {
   http2::index_header(request_hdidx_, token, request_headers_.size());
   request_headers_sum_ += namelen + valuelen;
-  http2::add_header(request_headers_, name, namelen, value, valuelen, no_index);
+  http2::add_header(request_headers_, name, namelen, value, valuelen, no_index,
+                    token);
 }
 
 bool Downstream::get_request_header_key_prev() const {
@@ -525,7 +527,8 @@ int Downstream::index_response_headers() {
                        response_content_length_);
 }
 
-const Headers::value_type *Downstream::get_response_header(int token) const {
+const Headers::value_type *
+Downstream::get_response_header(int16_t token) const {
   return http2::get_header(response_hdidx_, token, response_headers_);
 }
 
@@ -577,13 +580,21 @@ void Downstream::set_last_response_header_value(std::string value) {
   item.value = std::move(value);
 }
 
+void Downstream::add_response_header(std::string name, std::string value,
+                                     int16_t token) {
+  http2::index_header(response_hdidx_, token, response_headers_.size());
+  response_headers_sum_ += name.size() + value.size();
+  response_headers_.emplace_back(std::move(name), std::move(value), false,
+                                 token);
+}
+
 void Downstream::add_response_header(const uint8_t *name, size_t namelen,
                                      const uint8_t *value, size_t valuelen,
-                                     bool no_index, int token) {
+                                     bool no_index, int16_t token) {
   http2::index_header(response_hdidx_, token, response_headers_.size());
   response_headers_sum_ += namelen + valuelen;
-  http2::add_header(response_headers_, name, namelen, value, valuelen,
+  http2::add_header(response_headers_, name, namelen, value, valuelen, no_index,
-                    no_index);
+                    token);
 }
 
 bool Downstream::get_response_header_key_prev() const {
@@ -893,14 +904,14 @@ bool pseudo_header_allowed(const Headers &headers) {
 }
 } // namespace
 
-bool Downstream::request_pseudo_header_allowed(int token) const {
+bool Downstream::request_pseudo_header_allowed(int16_t token) const {
   if (!pseudo_header_allowed(request_headers_)) {
     return false;
   }
   return http2::check_http2_request_pseudo_header(request_hdidx_, token);
 }
 
-bool Downstream::response_pseudo_header_allowed(int token) const {
+bool Downstream::response_pseudo_header_allowed(int16_t token) const {
   if (!pseudo_header_allowed(response_headers_)) {
     return false;
   }

src/shrpx_downstream.h

@@ -108,7 +108,7 @@ public:
   // multiple header have |name| as name, return last occurrence from
   // the beginning.  If no such header is found, returns nullptr.
   // This function must be called after headers are indexed
-  const Headers::value_type *get_request_header(int token) const;
+  const Headers::value_type *get_request_header(int16_t token) const;
   // Returns pointer to the request header with the name |name|.  If
   // no such header is found, returns nullptr.
   const Headers::value_type *get_request_header(const std::string &name) const;
@@ -117,7 +117,7 @@ public:
 
   void add_request_header(const uint8_t *name, size_t namelen,
                           const uint8_t *value, size_t valuelen, bool no_index,
-                          int token);
+                          int16_t token);
 
   bool get_request_header_key_prev() const;
   void append_last_request_header_key(const char *data, size_t len);
@@ -165,7 +165,7 @@ public:
   bool validate_request_bodylen() const;
   int64_t get_request_content_length() const;
   void set_request_content_length(int64_t len);
-  bool request_pseudo_header_allowed(int token) const;
+  bool request_pseudo_header_allowed(int16_t token) const;
   bool expect_response_body() const;
   enum {
     INITIAL,
@@ -192,16 +192,17 @@ public:
   // multiple header have |name| as name, return last occurrence from
   // the beginning.  If no such header is found, returns nullptr.
   // This function must be called after response headers are indexed.
-  const Headers::value_type *get_response_header(int token) const;
+  const Headers::value_type *get_response_header(int16_t token) const;
   // Rewrites the location response header field.
   void rewrite_location_response_header(const std::string &upstream_scheme,
                                         uint16_t upstream_port);
   void add_response_header(std::string name, std::string value);
   void set_last_response_header_value(std::string value);
 
+  void add_response_header(std::string name, std::string value, int16_t token);
   void add_response_header(const uint8_t *name, size_t namelen,
                            const uint8_t *value, size_t valuelen, bool no_index,
-                           int token);
+                           int16_t token);
 
   bool get_response_header_key_prev() const;
   void append_last_response_header_key(const char *data, size_t len);
@@ -248,7 +249,7 @@ public:
   void dec_response_datalen(size_t len);
   size_t get_response_datalen() const;
   void reset_response_datalen();
-  bool response_pseudo_header_allowed(int token) const;
+  bool response_pseudo_header_allowed(int16_t token) const;
 
   // Call this method when there is incoming data in downstream
   // connection.

src/shrpx_http2_session.cc

@@ -823,7 +823,8 @@ int on_response_headers(Http2Session *http2session, Downstream *downstream,
       // Otherwise, use chunked encoding to keep upstream connection
       // open.  In HTTP2, we are supporsed not to receive
       // transfer-encoding.
-      downstream->add_response_header("transfer-encoding", "chunked");
+      downstream->add_response_header("transfer-encoding", "chunked",
+                                      http2::HD_TRANSFER_ENCODING);
       downstream->set_chunked_response(true);
     }
   }

src/shrpx_http2_upstream.cc

@@ -469,14 +469,6 @@ int on_frame_recv_callback(nghttp2_session *session, const nghttp2_frame *frame,
     }
     upstream->stop_settings_timer();
     break;
-  case NGHTTP2_PUSH_PROMISE:
-    rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
-                                   frame->push_promise.promised_stream_id,
-                                   NGHTTP2_REFUSED_STREAM);
-    if (rv != 0) {
-      return NGHTTP2_ERR_CALLBACK_FAILURE;
-    }
-    break;
   case NGHTTP2_GOAWAY:
     if (LOG_ENABLED(INFO)) {
       auto debug_data = util::ascii_dump(frame->goaway.opaque_data,
@@ -540,6 +532,51 @@ int on_frame_send_callback(nghttp2_session *session, const nghttp2_frame *frame,
       upstream->start_settings_timer();
     }
     break;
+  case NGHTTP2_PUSH_PROMISE: {
+    auto downstream = make_unique<Downstream>(
+        upstream, frame->push_promise.promised_stream_id, 0);
+
+    downstream->disable_upstream_rtimer();
+
+    downstream->set_request_major(2);
+    downstream->set_request_minor(0);
+
+    for (size_t i = 0; i < frame->push_promise.nvlen; ++i) {
+      auto &nv = frame->push_promise.nva[i];
+      auto token = http2::lookup_token(nv.name, nv.namelen);
+      switch (token) {
+      case http2::HD__METHOD:
+        downstream->set_request_method({nv.value, nv.value + nv.valuelen});
+        break;
+      case http2::HD__SCHEME:
+        downstream->set_request_http2_scheme(
+            {nv.value, nv.value + nv.valuelen});
+        break;
+      case http2::HD__AUTHORITY:
+        downstream->set_request_http2_authority(
+            {nv.value, nv.value + nv.valuelen});
+        break;
+      case http2::HD__PATH:
+        downstream->set_request_path({nv.value, nv.value + nv.valuelen});
+        break;
+      }
+      downstream->add_request_header(nv.name, nv.namelen, nv.value, nv.valuelen,
+                                     nv.flags & NGHTTP2_NV_FLAG_NO_INDEX,
+                                     token);
+    }
+
+    downstream->inspect_http2_request();
+
+    downstream->set_request_state(Downstream::MSG_COMPLETE);
+
+    // a bit weird but start_downstream() expects that given
+    // downstream is in pending queue.
+    auto ptr = downstream.get();
+    upstream->add_pending_downstream(std::move(downstream));
+    upstream->start_downstream(ptr);
+
+    break;
+  }
   case NGHTTP2_GOAWAY:
     if (LOG_ENABLED(INFO)) {
       auto debug_data = util::ascii_dump(frame->goaway.opaque_data,
@@ -1283,6 +1320,35 @@ int Http2Upstream::on_downstream_header_complete(Downstream *downstream) {
     return -1;
   }
 
+  // We need some conditions that must be fulfilled to initiate server
+  // push.
+  //
+  // * Server push is disabled for http2 proxy, since incoming headers
+  //   are mixed origins.  We don't know how to reliably determine the
+  //   authority yet.
+  //
+  // * If downstream is http/2, it is likely that PUSH_PROMISE is
+  //   coming from there, so we don't initiate PUSH_RPOMISE here.
+  //
+  // * We need 200 response code for associated resource.  This is too
+  //   restrictive, we will review this later.
+  //
+  // * We requires GET or POST for associated resource.  Probably we
+  //   don't want to push for HEAD request.  Not sure other methods
+  //   are also eligible for push.
+  if (!get_config()->no_server_push &&
+      get_config()->downstream_proto == PROTO_HTTP &&
+      !get_config()->http2_proxy && (downstream->get_stream_id() % 2) &&
+      downstream->get_response_header(http2::HD_LINK) &&
+      downstream->get_response_http_status() == 200 &&
+      (downstream->get_request_method() == "GET" ||
+       downstream->get_request_method() == "POST")) {
+
+    if (prepare_push_promise(downstream) != 0) {
+      return -1;
+    }
+  }
+
   return 0;
 }
 
@@ -1447,4 +1513,138 @@ int Http2Upstream::on_downstream_reset(bool no_retry) {
 
 MemchunkPool *Http2Upstream::get_mcpool() { return &mcpool_; }
 
+int Http2Upstream::prepare_push_promise(Downstream *downstream) {
+  int rv;
+  http_parser_url u;
+  memset(&u, 0, sizeof(u));
+  rv = http_parser_parse_url(downstream->get_request_path().c_str(),
+                             downstream->get_request_path().size(), 0, &u);
+  if (rv != 0) {
+    return 0;
+  }
+  const char *base;
+  size_t baselen;
+  if (u.field_set & (1 << UF_PATH)) {
+    auto &f = u.field_data[UF_PATH];
+    base = downstream->get_request_path().c_str() + f.off;
+    baselen = f.len;
+  } else {
+    base = "/";
+    baselen = 1;
+  }
+  for (auto &kv : downstream->get_response_headers()) {
+    if (kv.token != http2::HD_LINK) {
+      continue;
+    }
+    for (auto &link :
+         http2::parse_link_header(kv.value.c_str(), kv.value.size())) {
+      auto link_url = link.uri.first;
+      auto link_urllen = link.uri.second - link.uri.first;
+
+      const char *rel;
+      size_t rellen;
+      const char *relq = nullptr;
+      size_t relqlen = 0;
+
+      http_parser_url v;
+      memset(&v, 0, sizeof(v));
+      rv = http_parser_parse_url(link_url, link_urllen, 0, &v);
+      if (rv != 0) {
+        assert(link_urllen);
+        if (link_url[0] == '/') {
+          continue;
+        }
+        // treat link_url as relative URI.
+        auto end = std::find(link_url, link_url + link_urllen, '#');
+        auto q = std::find(link_url, end, '?');
+        rel = link_url;
+        rellen = q - link_url;
+        if (q != end) {
+          relq = q + 1;
+          relqlen = end - relq;
+        }
+      } else {
+        if (v.field_set & (1 << UF_HOST)) {
+          continue;
+        }
+        if (v.field_set & (1 << UF_PATH)) {
+          auto &f = v.field_data[UF_PATH];
+          rel = link_url + f.off;
+          rellen = f.len;
+        } else {
+          rel = "/";
+          rellen = 1;
+        }
+
+        if (v.field_set & (1 << UF_QUERY)) {
+          auto &f = v.field_data[UF_QUERY];
+          relq = link_url + f.off;
+          relqlen = f.len;
+        }
+      }
+      auto path = http2::path_join(base, baselen, nullptr, 0, rel, rellen, relq,
+                                   relqlen);
+      rv = submit_push_promise(path, downstream);
+      if (rv != 0) {
+        return -1;
+      }
+    }
+  }
+  return 0;
+}
+
+int Http2Upstream::submit_push_promise(const std::string &path,
+                                       Downstream *downstream) {
+  int rv;
+  std::vector<nghttp2_nv> nva;
+  nva.reserve(downstream->get_request_headers().size());
+  for (auto &kv : downstream->get_request_headers()) {
+    switch (kv.token) {
+    // TODO generate referer
+    case http2::HD__AUTHORITY:
+    case http2::HD__SCHEME:
+    case http2::HD_ACCEPT_ENCODING:
+    case http2::HD_ACCEPT_LANGUAGE:
+    case http2::HD_CACHE_CONTROL:
+    case http2::HD_HOST:
+    case http2::HD_USER_AGENT:
+      nva.push_back(http2::make_nv(kv.name, kv.value, kv.no_index));
+      break;
+    case http2::HD__METHOD:
+      // juse use "GET" for now
+      nva.push_back(http2::make_nv_lc(":method", "GET"));
+      continue;
+    case http2::HD__PATH:
+      nva.push_back(http2::make_nv_ls(":path", path));
+      continue;
+    }
+  }
+
+  rv = nghttp2_submit_push_promise(session_, NGHTTP2_FLAG_NONE,
+                                   downstream->get_stream_id(), nva.data(),
+                                   nva.size(), nullptr);
+
+  if (rv < 0) {
+    if (LOG_ENABLED(INFO)) {
+      ULOG(INFO, this) << "nghttp2_submit_push_promise() failed: "
+                       << nghttp2_strerror(rv);
+    }
+    if (nghttp2_is_fatal(rv)) {
+      return -1;
+    }
+    return 0;
+  }
+
+  if (LOG_ENABLED(INFO)) {
+    std::stringstream ss;
+    for (auto &nv : nva) {
+      ss << TTY_HTTP_HD << nv.name << TTY_RST << ": " << nv.value << "\n";
+    }
+    ULOG(INFO, this) << "HTTP push request headers. promised_stream_id=" << rv
+                     << "\n" << ss.str();
+  }
+
+  return 0;
+}
+
 } // namespace shrpx

src/shrpx_http2_upstream.h

@@ -100,6 +100,9 @@ public:
   void submit_goaway();
   void check_shutdown();
 
+  int prepare_push_promise(Downstream *downstream);
+  int submit_push_promise(const std::string &path, Downstream *downstream);
+
 private:
   // must be put before downstream_queue_
   std::unique_ptr<HttpsUpstream> pre_upstream_;

src/shrpx_spdy_upstream.cc

@@ -860,8 +860,7 @@ int SpdyUpstream::on_downstream_header_complete(Downstream *downstream) {
     if (hd.name.empty() || hd.name.c_str()[0] == ':') {
       continue;
     }
-    auto token = http2::lookup_token(hd.name);
+    switch (hd.token) {
-    switch (token) {
     case http2::HD_CONNECTION:
     case http2::HD_KEEP_ALIVE:
     case http2::HD_PROXY_CONNECTION:

src/util.cc

@@ -99,6 +99,12 @@ bool in_token(char c) {
              &extra[sizeof(extra)];
 }
 
+bool in_attr_char(char c) {
+  static const char bad[] = {'*', '\'', '%'};
+  return util::in_token(c) &&
+         std::find(std::begin(bad), std::end(bad) - 1, c) == std::end(bad) - 1;
+}
+
 std::string percent_encode_token(const std::string &target) {
   auto len = target.size();
   std::string dest;

src/util.h

@@ -163,6 +163,8 @@ bool inRFC3986UnreservedChars(const char c);
 // Returns true if |c| is in token (HTTP-p1, Section 3.2.6)
 bool in_token(char c);
 
+bool in_attr_char(char c);
+
 std::string percentEncode(const unsigned char *target, size_t len);
 
 std::string percentEncode(const std::string &target);