curl: add --false-start option

docs/curl.1

@@ -562,6 +562,15 @@ or no response at all is received, the verification fails.
 
 This is currently only implemented in the OpenSSL, GnuTLS and NSS backends.
 (Added in 7.41.0)
+.IP "--false-start"
+
+(SSL) Tells curl to 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.
+
+This is currently only implemented in the NSS backend.
+(Added in 7.42.0)
 .IP "-f, --fail"
 (HTTP) Fail silently (no output at all) on server errors. This is mostly done
 to better enable scripts etc to better deal with failed attempts. In normal

src/tool_cfgable.h

@@ -207,6 +207,8 @@ struct OperationConfig {
   bool noalpn;                    /* enable/disable TLS ALPN extension */
   char *unix_socket_path;         /* path to Unix domain socket */
 
+  bool falsestart;
+
   struct GlobalConfig *global;
   struct OperationConfig *prev;
   struct OperationConfig *next;   /* Always last in the struct */

src/tool_getparam.c

@@ -218,6 +218,7 @@ static const struct LongShort aliases[]= {
   {"Eo", "login-options",            TRUE},
   {"Ep", "pinnedpubkey",             TRUE},
   {"Eq", "cert-status",              FALSE},
+  {"Er", "false-start",              FALSE},
   {"f",  "fail",                     FALSE},
   {"F",  "form",                     TRUE},
   {"Fs", "form-string",              TRUE},
@@ -1368,6 +1369,10 @@ ParameterError getparameter(char *flag,    /* f or -long-flag */
         config->verifystatus = TRUE;
         break;
 
+      case 'r': /* --false-start */
+        config->falsestart = TRUE;
+        break;
+
       default: /* certificate file */
       {
         char *certname, *passphrase;

src/tool_help.c

@@ -83,6 +83,7 @@ static const char *const helptext[] = {
   "     --environment   Write results to environment variables (RISC OS)",
 #endif
   " -f, --fail          Fail silently (no output at all) on HTTP errors (H)",
+  "     --false-start   Enable TLS False Start.",
   " -F, --form CONTENT  Specify HTTP multipart POST data (H)",
   "     --form-string STRING  Specify HTTP multipart POST data (H)",
   "     --ftp-account DATA  Account data string (F)",

src/tool_operate.c

@@ -1041,6 +1041,9 @@ static CURLcode operate_do(struct GlobalConfig *global,
 
           if(config->verifystatus)
             my_setopt(curl, CURLOPT_SSL_VERIFYSTATUS, 1L);
+
+          if(config->falsestart)
+            my_setopt(curl, CURLOPT_SSL_FALSESTART, 1L);
         }
 
         if(built_in_protos & (CURLPROTO_SCP|CURLPROTO_SFTP)) {