nghttpd: Add -m, --max-concurrent-streams option

src/HttpServer.cc

@@ -89,9 +89,9 @@ template <typename Array> void append_nv(Stream *stream, const Array &nva) {
 Config::Config()
     : stream_read_timeout(60.), stream_write_timeout(60.),
       session_option(nullptr), data_ptr(nullptr), padding(0), num_worker(1),
-      header_table_size(-1), port(0), verbose(false), daemon(false),
+      max_concurrent_streams(100), header_table_size(-1), port(0),
-      verify_client(false), no_tls(false), error_gzip(false),
+      verbose(false), daemon(false), verify_client(false), no_tls(false),
-      early_response(false), hexdump(false) {
+      error_gzip(false), early_response(false), hexdump(false) {
   nghttp2_option_new(&session_option);
   nghttp2_option_set_recv_client_preface(session_option, 1);
 }
@@ -660,8 +660,10 @@ int Http2Handler::on_write() { return write_(*this); }
 int Http2Handler::connection_made() {
   int r;
 
+  auto config = sessions_->get_config();
+
   r = nghttp2_session_server_new2(&session_, sessions_->get_callbacks(), this,
-                                  sessions_->get_config()->session_option);
+                                  config->session_option);
   if (r != 0) {
     return r;
   }
@@ -669,11 +671,11 @@ int Http2Handler::connection_made() {
   size_t niv = 1;
 
   entry[0].settings_id = NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS;
-  entry[0].value = 100;
+  entry[0].value = config->max_concurrent_streams;
 
-  if (sessions_->get_config()->header_table_size >= 0) {
+  if (config->header_table_size >= 0) {
     entry[niv].settings_id = NGHTTP2_SETTINGS_HEADER_TABLE_SIZE;
-    entry[niv].value = sessions_->get_config()->header_table_size;
+    entry[niv].value = config->header_table_size;
     ++niv;
   }
   r = nghttp2_submit_settings(session_, NGHTTP2_FLAG_NONE, entry.data(), niv);

src/HttpServer.h

@@ -63,6 +63,7 @@ struct Config {
   void *data_ptr;
   size_t padding;
   size_t num_worker;
+  size_t max_concurrent_streams;
   ssize_t header_table_size;
   uint16_t port;
   bool verbose;

src/nghttpd.cc

@@ -88,6 +88,7 @@ void print_usage(std::ostream &out) {
 
 namespace {
 void print_help(std::ostream &out) {
+  Config config;
   print_usage(out);
   out << R"(
   <PORT>      Specify listening port number.
@@ -128,6 +129,10 @@ Options:
   -b, --padding=<N>
               Add at  most <N>  bytes to a  frame payload  as padding.
               Specify 0 to disable padding.
+  -m, --max-concurrent-streams=<N>
+              Set the maximum number of  the concurrent streams in one
+              HTTP/2 session.
+              Default: )" << config.max_concurrent_streams << R"(
   -n, --workers=<N>
               Set the number of worker threads.
               Default: 1
@@ -173,6 +178,7 @@ int main(int argc, char **argv) {
         {"header-table-size", required_argument, nullptr, 'c'},
         {"push", required_argument, nullptr, 'p'},
         {"padding", required_argument, nullptr, 'b'},
+        {"max-concurrent-streams", required_argument, nullptr, 'm'},
         {"workers", required_argument, nullptr, 'n'},
         {"error-gzip", no_argument, nullptr, 'e'},
         {"no-tls", no_argument, &flag, 1},
@@ -184,7 +190,7 @@ int main(int argc, char **argv) {
         {"hexdump", no_argument, &flag, 7},
         {nullptr, 0, nullptr, 0}};
     int option_index = 0;
-    int c = getopt_long(argc, argv, "DVb:c:d:ehn:p:va:", long_options,
+    int c = getopt_long(argc, argv, "DVb:c:d:ehm:n:p:va:", long_options,
                         &option_index);
     char *end;
     if (c == -1) {
@@ -209,6 +215,16 @@ int main(int argc, char **argv) {
     case 'e':
       config.error_gzip = true;
       break;
+    case 'm': {
+      // max-concurrent-streams option
+      auto n = util::parse_uint(optarg);
+      if (n == -1) {
+        std::cerr << "-m: invalid argument: " << optarg << std::endl;
+        exit(EXIT_FAILURE);
+      }
+      config.max_concurrent_streams = n;
+      break;
+    }
     case 'n':
 #ifdef NOTHREADS
       std::cerr << "-n: WARNING: Threading disabled at build time, "