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| .TH CURLOPT_OPENSOCKETFUNCTION 3 "16 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options" |
| .SH NAME |
| CURLOPT_OPENSOCKETFUNCTION \- set callback for opening sockets |
| .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; |
| |
| struct curl_sockaddr { |
| int family; |
| int socktype; |
| int protocol; |
| unsigned int addrlen; |
| struct sockaddr addr; |
| }; |
| |
| curl_socket_t opensocket_callback(void *clientp, |
| curlsocktype purpose, |
| struct curl_sockaddr *address); |
| |
| CURLcode curl_easy_setopt(CURL *handle, CURLOPT_OPENSOCKETFUNCTION, opensocket_callback); |
| .SH DESCRIPTION |
| Pass a pointer to your callback function, which should match the prototype |
| shown above. |
| |
| This callback function gets called by libcurl instead of the \fIsocket(2)\fP |
| call. The callback's \fIpurpose\fP argument identifies the exact purpose for |
| this particular socket: \fICURLSOCKTYPE_IPCXN\fP is for IP based connections |
| and \fICURLSOCKTYPE_ACCEPT\fP is for sockets created after accept() - such as |
| when doing active FTP. Future versions of libcurl may support more |
| purposes. |
| |
| The \fIclientp\fP pointer contains whatever user-defined value set using the |
| \fICURLOPT_OPENSOCKETDATA(3)\fP function. |
| |
| The callback gets the resolved peer address as the \fIaddress\fP argument and |
| is allowed to modify the address or refuse to connect completely. The callback |
| function should return the newly created socket or \fICURL_SOCKET_BAD\fP in |
| case no connection could be established or another error was detected. Any |
| additional \fIsetsockopt(2)\fP calls can of course be done on the socket at |
| the user's discretion. A \fICURL_SOCKET_BAD\fP return value from the callback |
| function will signal an unrecoverable error to libcurl and it will return |
| \fICURLE_COULDNT_CONNECT\fP from the function that triggered this callback. |
| This return code can be used for IP address blacklisting. |
| |
| If you want to pass in a socket with an already established connection, pass |
| the socket back with this callback and then use |
| \fICURLOPT_SOCKOPTFUNCTION(3)\fP to signal that it already is connected. |
| .SH DEFAULT |
| The default behavior is the equivalent of this: |
| .nf |
| return socket(addr->family, addr->socktype, addr->protocol); |
| .fi |
| .SH PROTOCOLS |
| All |
| .SH EXAMPLE |
| .SH AVAILABILITY |
| Added in 7.17.1. |
| .SH RETURN VALUE |
| Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. |
| .SH "SEE ALSO" |
| .BR CURLOPT_OPENSOCKETDATA "(3), " CURLOPT_SOCKOPTFUNCTION "(3), " |
| .BR CURLOPT_CLOSESOCKETFUNCTION "(3), " |