Disable HTTP/2 over NPN (with OpenSSL).

net/socket/ssl_client_socket_nss.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file includes code SSLClientSocketNSS::DoVerifyCertComplete() derived
 // from AuthCertificateCallback() in
 // mozilla/security/manager/ssl/src/nsNSSCallbacks.cpp.
 
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
@@ skipping 825 matching lines @@
                                     memio_Private* buffers) {
   DCHECK(OnNetworkTaskRunner());
   DCHECK(!nss_fd_);
   DCHECK(!nss_bufs_);
 
   nss_fd_ = socket;
   nss_bufs_ = buffers;
 
   SECStatus rv = SECSuccess;
 
-  if (!ssl_config_.next_protos.empty()) {
-    NextProtoVector next_protos = ssl_config_.next_protos;
+  if (!ssl_config_.alpn_protos.empty()) {
+    NextProtoVector alpn_protos = ssl_config_.alpn_protos;
     // TODO(bnc): Check ssl_config_.disabled_cipher_suites.
     if (!IsTLSVersionAdequateForHTTP2(ssl_config_))
-      DisableHTTP2(&next_protos);
+      DisableHTTP2(&alpn_protos);
     // |ssl_config_| has fallback protocol at the end of the list, but NSS
     // expects fallback at the first place, thus protocols need to be reordered.
-    ReorderNextProtos(&next_protos);
-    std::vector<uint8_t> wire_protos = SerializeNextProtos(next_protos);
+    ReorderNextProtos(&alpn_protos);
+    // NSS only supports a single protocol vector to be used with ALPN and NPN.
+    // Because of this limitation, |alpn_prototos| will be used for both.
+    // However, it is possible to enable ALPN and NPN separately.
+    std::vector<uint8_t> wire_protos = SerializeNextProtos(alpn_protos);
     rv = SSL_SetNextProtoNego(
         nss_fd_, wire_protos.empty() ? NULL : &wire_protos[0],
         wire_protos.size());
     if (rv != SECSuccess)
       LogFailedNSSFunction(*weak_net_log_, "SSL_SetNextProtoNego", "");
     rv = SSL_OptionSet(nss_fd_, SSL_ENABLE_ALPN, PR_TRUE);
     if (rv != SECSuccess)
       LogFailedNSSFunction(*weak_net_log_, "SSL_OptionSet", "SSL_ENABLE_ALPN");
-    rv = SSL_OptionSet(nss_fd_, SSL_ENABLE_NPN, PR_TRUE);
-    if (rv != SECSuccess)
-      LogFailedNSSFunction(*weak_net_log_, "SSL_OptionSet", "SSL_ENABLE_NPN");
+    if (!ssl_config_.npn_protos.empty()) {
+      rv = SSL_OptionSet(nss_fd_, SSL_ENABLE_NPN, PR_TRUE);
+      if (rv != SECSuccess)
+        LogFailedNSSFunction(*weak_net_log_, "SSL_OptionSet", "SSL_ENABLE_NPN");
+    }
   }
 
   rv = SSL_AuthCertificateHook(
       nss_fd_, SSLClientSocketNSS::Core::OwnAuthCertHandler, this);
   if (rv != SECSuccess) {
     LogFailedNSSFunction(*weak_net_log_, "SSL_AuthCertificateHook", "");
     return false;
   }
 
   rv = SSL_GetClientAuthDataHook(
@@ skipping 2308 matching lines @@
   return channel_id_service_;
 }
 
 SSLFailureState SSLClientSocketNSS::GetSSLFailureState() const {
   if (completed_handshake_)
     return SSL_FAILURE_NONE;
   return SSL_FAILURE_UNKNOWN;
 }
 
 }  // namespace net