QUIC UDP GSO

src/h2load.cc

@@ -35,6 +35,7 @@
 #  include <fcntl.h>
 #endif // HAVE_FCNTL_H
 #include <sys/mman.h>
+#include <netinet/udp.h>
 
 #include <cstdio>
 #include <cassert>
@@ -117,7 +118,8 @@ Config::Config()
       timing_script(false),
       base_uri_unix(false),
       unix_addr{},
-      rps(0.) {}
+      rps(0.),
+      no_udp_gso(false) {}
 
 Config::~Config() {
   if (addrs) {
@@ -1375,8 +1377,32 @@ int Client::write_tls() {
 }
 
 int Client::write_udp(const sockaddr *addr, socklen_t addrlen,
-                      const uint8_t *data, size_t datalen) {
+                      const uint8_t *data, size_t datalen, size_t gso_size) {
-  auto nwrite = sendto(fd, data, datalen, MSG_DONTWAIT, addr, addrlen);
+  iovec msg_iov;
+  msg_iov.iov_base = const_cast<uint8_t *>(data);
+  msg_iov.iov_len = datalen;
+
+  msghdr msg{};
+  msg.msg_name = const_cast<sockaddr *>(addr);
+  msg.msg_namelen = addrlen;
+  msg.msg_iov = &msg_iov;
+  msg.msg_iovlen = 1;
+
+#ifdef UDP_SEGMENT
+  std::array<uint8_t, CMSG_SPACE(sizeof(uint16_t))> msg_ctrl{};
+  if (gso_size && datalen > gso_size) {
+    msg.msg_control = msg_ctrl.data();
+    msg.msg_controllen = msg_ctrl.size();
+
+    auto cm = CMSG_FIRSTHDR(&msg);
+    cm->cmsg_level = SOL_UDP;
+    cm->cmsg_type = UDP_SEGMENT;
+    cm->cmsg_len = CMSG_LEN(sizeof(uint16_t));
+    *(reinterpret_cast<uint16_t *>(CMSG_DATA(cm))) = gso_size;
+  }
+#endif // UDP_SEGMENT
+
+  auto nwrite = sendmsg(fd, &msg, 0);
   if (nwrite < 0) {
     std::cerr << "sendto: errno=" << errno << std::endl;
   } else {
@@ -2183,6 +2209,8 @@ Options:
               Specify the supported groups.
               Default: )"
       << config.groups << R"(
+  --no-udp-gso
+              Disable UDP GSO.
   -v, --verbose
               Output debug information.
   --version   Display version information and exit.
@@ -2245,6 +2273,7 @@ int main(int argc, char **argv) {
         {"rps", required_argument, &flag, 12},
         {"groups", required_argument, &flag, 13},
         {"tls13-ciphers", required_argument, &flag, 14},
+        {"no-udp-gso", no_argument, &flag, 15},
         {nullptr, 0, nullptr, 0}};
     int option_index = 0;
     auto c = getopt_long(argc, argv,
@@ -2503,6 +2532,10 @@ int main(int argc, char **argv) {
         // --tls13-ciphers
         config.tls13_ciphers = optarg;
         break;
+      case 15:
+        // --no-udp-gso
+        config.no_udp_gso = true;
+        break;
       }
       break;
     default:

src/h2load.h

@@ -125,6 +125,8 @@ struct Config {
   std::vector<std::string> npn_list;
   // The number of request per second for each client.
   double rps;
+  // Disables GSO for UDP connections.
+  bool no_udp_gso;
 
   Config();
   ~Config();
@@ -458,7 +460,7 @@ struct Client {
   int read_quic();
   int write_quic();
   int write_udp(const sockaddr *addr, socklen_t addrlen, const uint8_t *data,
-                size_t datalen);
+                size_t datalen, size_t gso_size);
   void quic_close_connection();
 
   int quic_recv_crypto_data(ngtcp2_crypto_level crypto_level,

src/h2load_http3_session.cc

@@ -402,6 +402,15 @@ int Http3Session::block_stream(int64_t stream_id) {
   return 0;
 }
 
+int Http3Session::shutdown_stream_write(int64_t stream_id) {
+  auto rv = nghttp3_conn_shutdown_stream_write(conn_, stream_id);
+  if (rv != 0) {
+    client_->quic.last_error = quic::err_application(rv);
+    return -1;
+  }
+  return 0;
+}
+
 int Http3Session::add_write_offset(int64_t stream_id, size_t ndatalen) {
   auto rv = nghttp3_conn_add_write_offset(conn_, stream_id, ndatalen);
   if (rv != 0) {

src/h2load_http3_session.h

@@ -63,6 +63,7 @@ public:
   ssize_t write_stream(int64_t &stream_id, int &fin, nghttp3_vec *vec,
                        size_t veccnt);
   int block_stream(int64_t stream_id);
+  int shutdown_stream_write(int64_t stream_id);
   int add_write_offset(int64_t stream_id, size_t ndatalen);
   int add_ack_offset(int64_t stream_id, size_t datalen);
 

src/h2load_quic.cc

@@ -24,6 +24,8 @@
  */
 #include "h2load_quic.h"
 
+#include <netinet/udp.h>
+
 #include <iostream>
 
 #include <ngtcp2/ngtcp2_crypto_openssl.h>
@@ -425,7 +427,7 @@ void Client::quic_close_connection() {
   }
 
   write_udp(reinterpret_cast<sockaddr *>(ps.path.remote.addr),
-            ps.path.remote.addrlen, buf.data(), nwrite);
+            ps.path.remote.addrlen, buf.data(), nwrite, 0);
 }
 
 int Client::quic_on_key(ngtcp2_crypto_level level, const uint8_t *rx_secret,
@@ -554,7 +556,18 @@ int Client::write_quic() {
   }
 
   std::array<nghttp3_vec, 16> vec;
-  std::array<uint8_t, 1500> buf;
+  size_t pktcnt = 0;
+  size_t max_pktcnt =
+#ifdef UDP_SEGMENT
+      worker->config->no_udp_gso
+          ? 1
+          : std::min(static_cast<size_t>(10),
+                     static_cast<size_t>(64_k / quic.max_pktlen));
+#else  // !UDP_SEGMENT
+      1;
+#endif // !UDP_SEGMENT
+  std::array<uint8_t, 64_k> buf;
+  uint8_t *bufpos = buf.data();
   ngtcp2_path_storage ps;
 
   ngtcp2_path_storage_zero(&ps);
@@ -583,16 +596,20 @@ int Client::write_quic() {
     }
 
     auto nwrite = ngtcp2_conn_writev_stream(
-        quic.conn, &ps.path, nullptr, buf.data(), quic.max_pktlen, &ndatalen,
+        quic.conn, &ps.path, nullptr, bufpos, quic.max_pktlen, &ndatalen, flags,
-        flags, stream_id, reinterpret_cast<const ngtcp2_vec *>(v), vcnt,
+        stream_id, reinterpret_cast<const ngtcp2_vec *>(v), vcnt,
         timestamp(worker->loop));
     if (nwrite < 0) {
       switch (nwrite) {
       case NGTCP2_ERR_STREAM_DATA_BLOCKED:
+        assert(ndatalen == -1);
+        if (s->block_stream(stream_id) != 0) {
+          return -1;
+        }
+        continue;
       case NGTCP2_ERR_STREAM_SHUT_WR:
         assert(ndatalen == -1);
-
+        if (s->shutdown_stream_write(stream_id) != 0) {
-        if (s->block_stream(stream_id) != 0) {
           return -1;
         }
         continue;
@@ -613,11 +630,23 @@ int Client::write_quic() {
     quic_restart_pkt_timer();
 
     if (nwrite == 0) {
+      if (bufpos - buf.data()) {
+        write_udp(ps.path.remote.addr, ps.path.remote.addrlen, buf.data(),
+                  bufpos - buf.data(), quic.max_pktlen);
+      }
       return 0;
     }
 
-    write_udp(reinterpret_cast<sockaddr *>(ps.path.remote.addr),
+    bufpos += nwrite;
-              ps.path.remote.addrlen, buf.data(), nwrite);
+
+    // Assume that the path does not change.
+    if (++pktcnt == max_pktcnt ||
+        static_cast<size_t>(nwrite) < quic.max_pktlen) {
+      write_udp(ps.path.remote.addr, ps.path.remote.addrlen, buf.data(),
+                bufpos - buf.data(), quic.max_pktlen);
+      signal_write();
+      return 0;
+    }
   }
 }