preproxy: renamed what was added as SOCKS_PROXY

CURLOPT_SOCKS_PROXY -> CURLOPT_PRE_PROXY

Added the corresponding --preroxy command line option. Sets a SOCKS
proxy to connect to _before_ connecting to a HTTP(S) proxy.

1 files changed, 69 insertions, 0 deletions

diff --git a/docs/libcurl/opts/CURLOPT_PRE_PROXY.3 b/docs/libcurl/opts/CURLOPT_PRE_PROXY.3
new file mode 100644
index 000000000..035dd3ac6
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+++ b/docs/libcurl/opts/CURLOPT_PRE_PROXY.3
@@ -0,0 +1,69 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2016, 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 https://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_PRE_PROXY 3 "16 Nov 2016" "libcurl 7.52.0" "curl_easy_setopt options"
+.SH NAME
+CURLOPT_PRE_PROXY \- set pre-proxy to use
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PRE_PROXY, char *preproxy);
+.SH DESCRIPTION
+Set the \fIpreproxy\fP to use for the upcoming request. The parameter
+should be a char * to a zero terminated string holding the host name or dotted
+numerical IP address. A numerical IPv6 address must be written within
+[brackets].
+
+To specify port number in this string, append :[port] to the end of the host
+name. The proxy's port number may optionally be specified with the separate
+option \fICURLOPT_PROXYPORT(3)\fP. If not specified, libcurl will default to
+using port 1080 for proxies.
+
+A pre proxy is a SOCKS proxy that curl connects to before it connects to the
+HTTP(S) proxy specified in the \fICURLOPT_PROXY\fP option. The pre proxy can
+only be a SOCKS proxy.
+
+The pre proxy string should be prefixed with [scheme]:// to specify which kind
+of socks is used. Use socks4://, socks4a://, socks5:// or socks5h:// (the last
+one to enable socks5 and asking the proxy to do the resolving, also known as
+\fICURLPROXY_SOCKS5_HOSTNAME\fP type) to request the specific SOCKS version to
+be used. Otherwise SOCKS4 is used as default.
+
+Setting the pre proxy string to "" (an empty string) will explicitly disable
+the use of a pre proxy.
+.SH DEFAULT
+Default is NULL, meaning no pre proxy is used.
+
+When you set a host name to use, do not assume that there's any particular
+single port number used widely for proxies. Specify it!
+.SH PROTOCOLS
+All except file://. Note that some protocols don't do very well over proxy.
+.SH EXAMPLE
+TODO
+.SH AVAILABILITY
+Added in 7.52.0
+.SH RETURN VALUE
+Returns CURLE_OK if proxies are supported, CURLE_UNKNOWN_OPTION if not, or
+CURLE_OUT_OF_MEMORY if there was insufficient heap space.
+.SH "SEE ALSO"
+.BR CURLOPT_PROXY "(3), " CURLOPT_HTTPPROXYTUNNEL "(3), "
+