125 lines
4.9 KiB
Groff
125 lines
4.9 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) 1998 - 2017, 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_SOCKOPTFUNCTION 3 "16 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
|
|
.SH NAME
|
|
CURLOPT_SOCKOPTFUNCTION \- set callback for setting socket options
|
|
.SH SYNOPSIS
|
|
.nf
|
|
#include <curl/curl.h>
|
|
|
|
typedef enum {
|
|
CURLSOCKTYPE_IPCXN, /* socket created for a specific IP connection */
|
|
CURLSOCKTYPE_ACCEPT, /* socket created by accept() call */
|
|
CURLSOCKTYPE_LAST /* never use */
|
|
} curlsocktype;
|
|
|
|
#define CURL_SOCKOPT_OK 0
|
|
#define CURL_SOCKOPT_ERROR 1 /* causes libcurl to abort and return
|
|
CURLE_ABORTED_BY_CALLBACK */
|
|
#define CURL_SOCKOPT_ALREADY_CONNECTED 2
|
|
|
|
int sockopt_callback(void *clientp,
|
|
curl_socket_t curlfd,
|
|
curlsocktype purpose);
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
|
|
.SH DESCRIPTION
|
|
Pass a pointer to your callback function, which should match the prototype
|
|
shown above.
|
|
|
|
When set, this callback function gets called by libcurl when the socket has
|
|
been created, but before the connect call to allow applications to change
|
|
specific socket options. The callback's \fIpurpose\fP argument identifies the
|
|
exact purpose for this particular socket:
|
|
|
|
\fICURLSOCKTYPE_IPCXN\fP for actively created connections or since 7.28.0
|
|
\fICURLSOCKTYPE_ACCEPT\fP for FTP when the connection was setup with PORT/EPSV
|
|
(in earlier versions these sockets weren't passed to this callback).
|
|
|
|
Future versions of libcurl may support more purposes. libcurl passes the newly
|
|
created socket descriptor to the callback in the \fIcurlfd\fP parameter so
|
|
additional setsockopt() calls can be done at the user's discretion.
|
|
|
|
The \fIclientp\fP pointer contains whatever user-defined value set using the
|
|
\fICURLOPT_SOCKOPTDATA(3)\fP function.
|
|
|
|
Return \fICURL_SOCKOPT_OK\fP from the callback on success. Return
|
|
\fICURL_SOCKOPT_ERROR\fP from the callback function to signal an unrecoverable
|
|
error to the library and it will close the socket and return
|
|
\fICURLE_COULDNT_CONNECT\fP.
|
|
Alternatively, the callback function can return
|
|
\fICURL_SOCKOPT_ALREADY_CONNECTED\fP, to tell libcurl that the socket is
|
|
already connected and then libcurl will not attempt to connect it. This allows
|
|
an application to pass in an already connected socket with
|
|
\fICURLOPT_OPENSOCKETFUNCTION(3)\fP and then have this function make libcurl
|
|
not attempt to connect (again).
|
|
.SH DEFAULT
|
|
By default, this callback is NULL and unused.
|
|
.SH PROTOCOLS
|
|
All
|
|
.SH EXAMPLE
|
|
.nf
|
|
/* make libcurl use the already established socket 'sockfd' */
|
|
|
|
static curl_socket_t opensocket(void *clientp,
|
|
curlsocktype purpose,
|
|
struct curl_sockaddr *address)
|
|
{
|
|
curl_socket_t sockfd;
|
|
sockfd = *(curl_socket_t *)clientp;
|
|
/* the actual externally set socket is passed in via the OPENSOCKETDATA
|
|
option */
|
|
return sockfd;
|
|
}
|
|
|
|
static int sockopt_callback(void *clientp, curl_socket_t curlfd,
|
|
curlsocktype purpose)
|
|
{
|
|
/* This return code was added in libcurl 7.21.5 */
|
|
return CURL_SOCKOPT_ALREADY_CONNECTED;
|
|
}
|
|
|
|
curl = curl_easy_init();
|
|
if(curl) {
|
|
/* libcurl will internally think that you connect to the host
|
|
* and port that you specify in the URL option. */
|
|
curl_easy_setopt(curl, CURLOPT_URL, "http://99.99.99.99:9999");
|
|
/* call this function to get a socket */
|
|
curl_easy_setopt(curl, CURLOPT_OPENSOCKETFUNCTION, opensocket);
|
|
curl_easy_setopt(curl, CURLOPT_OPENSOCKETDATA, &sockfd);
|
|
|
|
/* call this function to set options for the socket */
|
|
curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
|
|
|
|
res = curl_easy_perform(curl);
|
|
|
|
curl_easy_cleanup(curl);
|
|
.fi
|
|
.SH AVAILABILITY
|
|
Added in 7.16.0. The \fICURL_SOCKOPT_ALREADY_CONNECTED\fP return code was
|
|
added in 7.21.5.
|
|
.SH RETURN VALUE
|
|
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
|
|
.SH "SEE ALSO"
|
|
.BR CURLOPT_SOCKOPTDATA "(3), " CURLOPT_OPENSOCKETFUNCTION "(3), "
|