nghttpx: Add support QUIC BBR2

src/shrpx.cc

@@ -3369,12 +3369,15 @@ HTTP/3 and QUIC:
               NEW_TOKEN frame in the previous connection.
   --frontend-quic-congestion-controller=<CC>
               Specify a congestion controller algorithm for a frontend
-              QUIC  connection.   <CC>  should be  either  "cubic"  or
-              "bbr".
+              QUIC connection.  <CC> should  be one of "cubic", "bbr",
+              and "bbr2".
               Default: )"
       << (config->quic.upstream.congestion_controller == NGTCP2_CC_ALGO_CUBIC
               ? "cubic"
-              : "bbr")
+              : (config->quic.upstream.congestion_controller ==
+                         NGTCP2_CC_ALGO_BBR
+                     ? "bbr"
+                     : "bbr2"))
       << R"(
   --frontend-quic-secret-file=<PATH>
               Path to file that contains secure random data to be used

src/shrpx_config.cc

@@ -4111,8 +4111,10 @@ int parse_config(Config *config, int optid, const StringRef &opt,
       config->quic.upstream.congestion_controller = NGTCP2_CC_ALGO_CUBIC;
     } else if (util::strieq_l("bbr", optarg)) {
       config->quic.upstream.congestion_controller = NGTCP2_CC_ALGO_BBR;
+    } else if (util::strieq_l("bbr2", optarg)) {
+      config->quic.upstream.congestion_controller = NGTCP2_CC_ALGO_BBR2;
     } else {
-      LOG(ERROR) << opt << ": must be either cubic or bbr";
+      LOG(ERROR) << opt << ": must be one of cubic, bbr, and bbr2";
       return -1;
     }
 #endif // ENABLE_HTTP3

src/shrpx_http3_upstream.cc

@@ -745,7 +745,11 @@ int Http3Upstream::write_streams() {
   auto config = get_config();
   auto &quicconf = config->quic;
 
-  if (quicconf.upstream.congestion_controller != NGTCP2_CC_ALGO_BBR) {
+  switch (quicconf.upstream.congestion_controller) {
+  case NGTCP2_CC_ALGO_BBR:
+  case NGTCP2_CC_ALGO_BBR2:
+    break;
+  default:
     max_pktcnt = std::min(max_pktcnt, static_cast<size_t>(10));
   }