nghttpx: Add --no-location-rewrite option

--no-location-rewrite option disallows location header rewrite on
--http2-bridge, --client and default mode.  This option is useful when
connecting nghttpx proxy with --http2-bridge to backend nghttpx with
http2-proxy mode.

src/shrpx.cc

@@ -569,6 +569,7 @@ void fill_default_config()
 
   mod_config()->tls_proto_mask = 0;
   mod_config()->cached_time = generate_time();
+  mod_config()->no_location_rewrite = false;
 }
 } // namespace
 
@@ -873,6 +874,12 @@ Misc:
                      downstream request.
   --no-via           Don't append to Via  header field.  If Via header
                      field is received, it is left unaltered.
+  --no-location-rewrite
+                     Don't   rewrite   location    header   field   on
+                     --http2-bridge, --client  and default  mode.  For
+                     --http2-proxy  and --client-proxy  mode, location
+                     header field  will not  be altered  regardless of
+                     this option.
   --altsvc=<PROTOID,PORT[,HOST,[ORIGIN]]>
                      Specify  protocol ID,  port, host  and origin  of
                      alternative  service.   <HOST> and  <ORIGIN>  are
@@ -995,6 +1002,7 @@ int main(int argc, char **argv)
       {"errorlog-syslog", no_argument, &flag, 59},
       {"stream-read-timeout", required_argument, &flag, 60},
       {"stream-write-timeout", required_argument, &flag, 61},
+      {"no-location-rewrite", no_argument, &flag, 62},
       {nullptr, 0, nullptr, 0 }
     };
 
@@ -1263,6 +1271,10 @@ int main(int argc, char **argv)
         // --stream-write-timeout
         cmdcfgs.emplace_back(SHRPX_OPT_STREAM_WRITE_TIMEOUT, optarg);
         break;
+      case 62:
+        // --no-location-rewrite
+        cmdcfgs.emplace_back(SHRPX_OPT_NO_LOCATION_REWRITE, "yes");
+        break;
       default:
         break;
       }

src/shrpx_config.cc

@@ -124,6 +124,7 @@ const char SHRPX_OPT_ALTSVC[] = "altsvc";
 const char SHRPX_OPT_ADD_RESPONSE_HEADER[] = "add-response-header";
 const char SHRPX_OPT_WORKER_FRONTEND_CONNECTIONS[] =
   "worker-frontend-connections";
+const char SHRPX_OPT_NO_LOCATION_REWRITE[] = "no-location-rewrite";
 
 namespace {
 Config *config = nullptr;
@@ -840,6 +841,12 @@ int parse_config(const char *opt, const char *optarg)
     return 0;
   }
 
+  if(util::strieq(opt, SHRPX_OPT_NO_LOCATION_REWRITE)) {
+    mod_config()->no_location_rewrite = util::strieq(optarg, "yes");
+
+    return 0;
+  }
+
   if(util::strieq(opt, "conf")) {
     LOG(WARNING) << "conf is ignored";
 

src/shrpx_config.h

@@ -114,6 +114,7 @@ extern const char SHRPX_OPT_PADDING[];
 extern const char SHRPX_OPT_ALTSVC[];
 extern const char SHRPX_OPT_ADD_RESPONSE_HEADER[];
 extern const char SHRPX_OPT_WORKER_FRONTEND_CONNECTIONS[];
+extern const char SHRPX_OPT_NO_LOCATION_REWRITE[];
 
 union sockaddr_union {
   sockaddr sa;
@@ -259,6 +260,7 @@ struct Config {
   bool backend_ipv6;
   bool http2_no_cookie_crumbling;
   bool upstream_frame_debug;
+  bool no_location_rewrite;
 };
 
 const Config* get_config();

src/shrpx_http2_upstream.cc

@@ -1174,7 +1174,8 @@ int Http2Upstream::on_downstream_header_complete(Downstream *downstream)
   }
 
   downstream->normalize_response_headers();
-  if(!get_config()->http2_proxy && !get_config()->client_proxy) {
+  if(!get_config()->http2_proxy && !get_config()->client_proxy &&
+     !get_config()->no_location_rewrite) {
     downstream->rewrite_norm_location_response_header
       (get_client_handler()->get_upstream_scheme(), get_config()->port);
   }

src/shrpx_https_upstream.cc

@@ -765,7 +765,8 @@ int HttpsUpstream::on_downstream_header_complete(Downstream *downstream)
   hdrs += http2::get_status_string(downstream->get_response_http_status());
   hdrs += "\r\n";
   downstream->normalize_response_headers();
-  if(!get_config()->http2_proxy && !get_config()->client_proxy) {
+  if(!get_config()->http2_proxy && !get_config()->client_proxy &&
+     !get_config()->no_location_rewrite) {
     downstream->rewrite_norm_location_response_header
       (get_client_handler()->get_upstream_scheme(), get_config()->port);
   }

src/shrpx_spdy_upstream.cc

@@ -911,7 +911,8 @@ int SpdyUpstream::on_downstream_header_complete(Downstream *downstream)
     DLOG(INFO, downstream) << "HTTP response header completed";
   }
   downstream->normalize_response_headers();
-  if(!get_config()->http2_proxy && !get_config()->client_proxy) {
+  if(!get_config()->http2_proxy && !get_config()->client_proxy &&
+     !get_config()->no_location_rewrite) {
     downstream->rewrite_norm_location_response_header
       (get_client_handler()->get_upstream_scheme(), get_config()->port);
   }