allow setting max frame size for h2load

src/h2load.cc

@@ -106,6 +106,7 @@ Config::Config()
       max_concurrent_streams(1),
       window_bits(30),
       connection_window_bits(30),
+      max_frame_size(16_k),
       rate(0),
       rate_period(1.0),
       duration(0.0),
@@ -2109,6 +2110,11 @@ Options:
               http/1.1  is used,  this  specifies the  number of  HTTP
               pipelining requests in-flight.
               Default: 1
+  -f, --max-frame-size=<SIZE>
+              Maximum frame size that the local endpoint is willing to
+              receive.
+              Default: )"
+      << util::utos_unit(config.max_frame_size) << R"(
   -w, --window-bits=<N>
               Sets the stream level initial window size to (2**<N>)-1.
               For QUIC, <N> is capped to 26 (roughly 64MiB).
@@ -2301,6 +2307,7 @@ int main(int argc, char **argv) {
         {"threads", required_argument, nullptr, 't'},
         {"max-concurrent-streams", required_argument, nullptr, 'm'},
         {"window-bits", required_argument, nullptr, 'w'},
+        {"max-frame-size", required_argument, nullptr, 'f'},
         {"connection-window-bits", required_argument, nullptr, 'W'},
         {"input-file", required_argument, nullptr, 'i'},
         {"header", required_argument, nullptr, 'H'},
@@ -2332,7 +2339,7 @@ int main(int argc, char **argv) {
         {nullptr, 0, nullptr, 0}};
     int option_index = 0;
     auto c = getopt_long(argc, argv,
-                         "hvW:c:d:m:n:p:t:w:H:i:r:T:N:D:B:", long_options,
+                         "hvW:c:d:m:n:p:t:w:f:H:i:r:T:N:D:B:", long_options,
                          &option_index);
     if (c == -1) {
       break;
@@ -2378,6 +2385,24 @@ int main(int argc, char **argv) {
       }
       break;
     }
+    case 'f': {
+      auto n = util::parse_uint_with_unit(optarg);
+      if (n == -1) {
+        std::cerr << "--max-frame-size: bad option value: " << optarg
+                  << std::endl;
+        exit(EXIT_FAILURE);
+      }
+      if (static_cast<uint64_t>(n) < 16_k) {
+        std::cerr << "--max-frame-size: minimum 16384" << std::endl;
+        exit(EXIT_FAILURE);
+      }
+      if (static_cast<uint64_t>(n) > 16_m - 1) {
+        std::cerr << "--max-frame-size: maximum 16777215" << std::endl;
+        exit(EXIT_FAILURE);
+      }
+      config.max_frame_size = n;
+      break;
+    }
     case 'H': {
       char *header = optarg;
       // Skip first possible ':' in the header name

src/h2load.h

@@ -95,6 +95,7 @@ struct Config {
   ssize_t max_concurrent_streams;
   size_t window_bits;
   size_t connection_window_bits;
+  size_t max_frame_size;
   // rate at which connections should be made
   size_t rate;
   ev_tstamp rate_period;

src/h2load_http2_session.cc

@@ -215,7 +215,7 @@ void Http2Session::on_connect() {
 
   nghttp2_option_del(opt);
 
-  std::array<nghttp2_settings_entry, 3> iv;
+  std::array<nghttp2_settings_entry, 4> iv;
   size_t niv = 2;
   iv[0].settings_id = NGHTTP2_SETTINGS_ENABLE_PUSH;
   iv[0].value = 0;
@@ -227,6 +227,11 @@ void Http2Session::on_connect() {
     iv[niv].value = config->header_table_size;
     ++niv;
   }
+  if (config->max_frame_size != 16_k) {
+    iv[niv].settings_id = NGHTTP2_SETTINGS_MAX_FRAME_SIZE;
+    iv[niv].value = config->max_frame_size;
+    ++niv;
+  }
 
   rv = nghttp2_submit_settings(session_, NGHTTP2_FLAG_NONE, iv.data(), niv);