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Diffstat (limited to 'docs/libcurl/opts/GNURLOPT_SOCKOPTFUNCTION.3')
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diff --git a/docs/libcurl/opts/GNURLOPT_SOCKOPTFUNCTION.3 b/docs/libcurl/opts/GNURLOPT_SOCKOPTFUNCTION.3 new file mode 100644 index 000000000..2f8a2c9ea --- /dev/null +++ b/docs/libcurl/opts/GNURLOPT_SOCKOPTFUNCTION.3 @@ -0,0 +1,124 @@ +.\" ************************************************************************** +.\" * _ _ ____ _ +.\" * 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 <gnurl/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), " |