url: add CURLOPT_SSL_FALSESTART option

This option can be used to enable/disable TLS False Start defined in the RFC draft-bmoeller-tls-falsestart.
curl · Mar 20, 2015 · 4dcd25e · 4dcd25e
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diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3
@@ -436,6 +436,8 @@ Enable use of NPN. See \fICURLOPT_SSL_ENABLE_NPN(3)\fP
 Use identifier with SSL engine. See \fICURLOPT_SSLENGINE(3)\fP
 .IP CURLOPT_SSLENGINE_DEFAULT
 Default SSL engine. See \fICURLOPT_SSLENGINE_DEFAULT(3)\fP
+.IP CURLOPT_SSL_FALSESTART
+Enable TLS False Start. See \fICURLOPT_SSL_FALSESTART(3)\fP
 .IP CURLOPT_SSLVERSION
 SSL version to use. See \fICURLOPT_SSLVERSION(3)\fP
 .IP CURLOPT_SSL_VERIFYHOST

diff --git a/docs/libcurl/opts/CURLOPT_SSL_FALSESTART.3 b/docs/libcurl/opts/CURLOPT_SSL_FALSESTART.3
@@ -0,0 +1,48 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" *
+.\" * This software is licensed as described in the file COPYING, which
+.\" * you should have received as part of this distribution. The terms
+.\" * are also available at http://curl.haxx.se/docs/copyright.html.
+.\" *
+.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+.\" * copies of the Software, and permit persons to whom the Software is
+.\" * furnished to do so, under the terms of the COPYING file.
+.\" *
+.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+.\" * KIND, either express or implied.
+.\" *
+.\" **************************************************************************
+.\"
+.TH CURLOPT_SSL_FALSESTART 3 "14 Feb 2015" "libcurl 7.41.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_SSL_FALSESTART \- enable TLS false start
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_FALSESTART, long enable);
+.SH DESCRIPTION
+Pass a long as parameter set to 1 to enable or 0 to disable.
+
+This option determines whether libcurl should use false start during the TLS
+handshake. False start is a mode where a TLS client will start sending
+application data before verifying the server's Finished message, thus saving a
+round trip when performing a full handshake.
+.SH DEFAULT
+0
+.SH PROTOCOLS
+All TLS based protocols: HTTPS, FTPS, IMAPS, POP3, SMTPS etc.
+.SH EXAMPLE
+TODO
+.SH AVAILABILITY
+Added in 7.42.0. This option is currently only supported by the NSS TLS
+backend.
+.SH RETURN VALUE
+Returns CURLE_OK if false start is supported by the SSL backend, otherwise
+returns CURLE_NOT_BUILT_IN.
diff --git a/docs/libcurl/opts/Makefile.am b/docs/libcurl/opts/Makefile.am
@@ -90,7 +90,8 @@ man_MANS = CURLOPT_ACCEPT_ENCODING.3 CURLOPT_ACCEPTTIMEOUT_MS.3		\
  CURLOPT_SSLCERT.3 CURLOPT_SSLCERTTYPE.3 CURLOPT_SSL_CIPHER_LIST.3	\
  CURLOPT_SSL_CTX_DATA.3 CURLOPT_SSL_CTX_FUNCTION.3			\
  CURLOPT_SSL_ENABLE_ALPN.3 CURLOPT_SSL_ENABLE_NPN.3 CURLOPT_SSLENGINE.3	\
- CURLOPT_SSLENGINE_DEFAULT.3 CURLOPT_SSLKEY.3 CURLOPT_SSLKEYTYPE.3	\
+ CURLOPT_SSLENGINE_DEFAULT.3 CURLOPT_SSL_FALSESTART.3			\
+ CURLOPT_SSLKEY.3 CURLOPT_SSLKEYTYPE.3					\
  CURLOPT_SSL_OPTIONS.3 CURLOPT_SSL_SESSIONID_CACHE.3			\
  CURLOPT_SSL_VERIFYHOST.3 CURLOPT_SSL_VERIFYPEER.3			\
  CURLOPT_SSL_VERIFYSTATUS.3 CURLOPT_SSLVERSION.3 CURLOPT_STDERR.3	\
@@ -193,8 +194,8 @@ HTMLPAGES = CURLOPT_ACCEPT_ENCODING.html CURLOPT_ACCEPTTIMEOUT_MS.html	\
  CURLOPT_SSL_CIPHER_LIST.html CURLOPT_SSL_CTX_DATA.html			\
  CURLOPT_SSL_CTX_FUNCTION.html CURLOPT_SSL_ENABLE_ALPN.html		\
  CURLOPT_SSL_ENABLE_NPN.html CURLOPT_SSLENGINE.html			\
- CURLOPT_SSLENGINE_DEFAULT.html CURLOPT_SSLKEY.html			\
- CURLOPT_SSLKEYTYPE.html CURLOPT_SSL_OPTIONS.html			\
+ CURLOPT_SSLENGINE_DEFAULT.html CURLOPT_SSL_FALSESTART.html		\
+ CURLOPT_SSLKEY.html CURLOPT_SSLKEYTYPE.html CURLOPT_SSL_OPTIONS.html	\
  CURLOPT_SSL_SESSIONID_CACHE.html CURLOPT_SSL_VERIFYHOST.html		\
  CURLOPT_SSL_VERIFYPEER.html CURLOPT_SSL_VERIFYSTATUS.html		\
  CURLOPT_SSLVERSION.html CURLOPT_STDERR.html CURLOPT_TCP_KEEPALIVE.html	\
@@ -296,8 +297,8 @@ PDFPAGES = CURLOPT_ACCEPT_ENCODING.pdf CURLOPT_ACCEPTTIMEOUT_MS.pdf	\
  CURLOPT_SSL_CIPHER_LIST.pdf CURLOPT_SSL_CTX_DATA.pdf			\
  CURLOPT_SSL_CTX_FUNCTION.pdf CURLOPT_SSL_ENABLE_ALPN.pdf		\
  CURLOPT_SSL_ENABLE_NPN.pdf CURLOPT_SSLENGINE.pdf			\
- CURLOPT_SSLENGINE_DEFAULT.pdf CURLOPT_SSLKEY.pdf			\
- CURLOPT_SSLKEYTYPE.pdf CURLOPT_SSL_OPTIONS.pdf				\
+ CURLOPT_SSLENGINE_DEFAULT.pdf CURLOPT_SSL_FALSESTART.pdf		\
+ CURLOPT_SSLKEY.pdf CURLOPT_SSLKEYTYPE.pdf CURLOPT_SSL_OPTIONS.pdf	\
  CURLOPT_SSL_SESSIONID_CACHE.pdf CURLOPT_SSL_VERIFYHOST.pdf		\
  CURLOPT_SSL_VERIFYPEER.pdf CURLOPT_SSL_VERIFYSTATUS.pdf		\
  CURLOPT_SSLVERSION.pdf CURLOPT_STDERR.pdf CURLOPT_TCP_KEEPALIVE.pdf	\

diff --git a/docs/libcurl/symbols-in-versions b/docs/libcurl/symbols-in-versions
@@ -510,6 +510,7 @@ CURLOPT_SSL_CTX_DATA            7.10.6
 CURLOPT_SSL_CTX_FUNCTION        7.10.6
 CURLOPT_SSL_ENABLE_ALPN         7.36.0
 CURLOPT_SSL_ENABLE_NPN          7.36.0
+CURLOPT_SSL_FALSESTART          7.42.0
 CURLOPT_SSL_OPTIONS             7.25.0
 CURLOPT_SSL_SESSIONID_CACHE     7.16.0
 CURLOPT_SSL_VERIFYHOST          7.8.1

diff --git a/include/curl/curl.h b/include/curl/curl.h
@@ -1626,6 +1626,9 @@ typedef enum {
   /* Set if we should verify the certificate status. */
   CINIT(SSL_VERIFYSTATUS, LONG, 232),
 
+  /* Set if we should enable TLS false start. */
+  CINIT(SSL_FALSESTART, LONG, 233),
+
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;
 

diff --git a/lib/url.c b/lib/url.c
@@ -2027,6 +2027,17 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
     result = CURLE_NOT_BUILT_IN;
 #endif
     break;
+  case CURLOPT_SSL_FALSESTART:
+    /*
+     * Enable TLS false start.
+     */
+    if(!Curl_ssl_false_start()) {
+      result = CURLE_NOT_BUILT_IN;
+      break;
+    }
+
+    data->set.ssl.falsestart = (0 != va_arg(param, long))?TRUE:FALSE;
+    break;
   case CURLOPT_CERTINFO:
 #ifdef have_curlssl_certinfo
     data->set.ssl.certinfo = (0 != va_arg(param, long))?TRUE:FALSE;

diff --git a/lib/urldata.h b/lib/urldata.h
@@ -351,6 +351,7 @@ struct ssl_config_data {
   void *fsslctxp;        /* parameter for call back */
   bool sessionid;        /* cache session IDs or not */
   bool certinfo;         /* gather lots of certificate info */
+  bool falsestart;
 
 #ifdef USE_TLS_SRP
   char *username; /* TLS username (for, e.g., SRP) */

diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
@@ -857,4 +857,16 @@ bool Curl_ssl_cert_status_request(void)
 #endif
 }
 
+/*
+ * Check whether the SSL backend supports false start.
+ */
+bool Curl_ssl_false_start(void)
+{
+#ifdef curlssl_false_start
+  return curlssl_false_start();
+#else
+  return FALSE;
+#endif
+}
+
 #endif /* USE_SSL */
diff --git a/lib/vtls/vtls.h b/lib/vtls/vtls.h
@@ -118,6 +118,8 @@ CURLcode Curl_pin_peer_pubkey(const char *pinnedpubkey,
 
 bool Curl_ssl_cert_status_request(void);
 
+bool Curl_ssl_false_start(void);
+
 #define SSL_SHUTDOWN_TIMEOUT 10000 /* ms */
 
 #else
@@ -145,6 +147,7 @@ bool Curl_ssl_cert_status_request(void);
 #define Curl_ssl_kill_session(x) Curl_nop_stmt
 #define Curl_ssl_random(x,y,z) ((void)x, CURLE_NOT_BUILT_IN)
 #define Curl_ssl_cert_status_request() FALSE
+#define Curl_ssl_false_start() FALSE
 #endif
 
 #endif /* HEADER_CURL_VTLS_H */