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| .TH CURLOPT_SSH_HOSTKEYFUNCTION 3 "4 Nov 2021" "libcurl 7.84.0" "curl_easy_setopt options" |
| .SH NAME |
| CURLOPT_SSH_HOSTKEYFUNCTION \- callback to check hostkey |
| .SH SYNOPSIS |
| .nf |
| #include <curl/curl.h> |
| |
| int keycallback(void *clientp, |
| int keytype, |
| const char *key, |
| size_t keylen); |
| |
| CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_HOSTKEYFUNCTION, |
| keycallback); |
| .fi |
| .SH DESCRIPTION |
| Pass a pointer to your callback function, which should match the prototype |
| shown above. It overrides \fICURLOPT_SSH_KNOWNHOSTS(3)\fP. |
| |
| This callback gets called when the verification of the SSH hostkey is needed. |
| |
| \fBkey\fP is \fBkeylen\fP bytes long and is the key to check. \fBkeytype\fP |
| says what type it is, from the \fBCURLKHTYPE_*\fP series in the curl_khtype |
| enum. |
| |
| \fBclientp\fP is a custom pointer set with \fICURLOPT_SSH_HOSTKEYDATA(3)\fP. |
| |
| The callback MUST return one of the following return codes to tell libcurl how |
| to act: |
| .IP CURLKHMATCH_OK |
| The hostkey is accepted, the connection should continue. |
| .IP CURLKHMATCH_MISMATCH |
| the hostkey is rejected, the connection is canceled. |
| .SH DEFAULT |
| NULL |
| .SH PROTOCOLS |
| SCP and SFTP |
| .SH EXAMPLE |
| .nf |
| int hostkeycb(void *clientp, /* passed with CURLOPT_SSH_HOSTKEYDATA */ |
| int keytype, /* CURLKHTYPE */ |
| const char * key, /*hostkey to check*/ |
| size_t keylen); /*length of the key*/ |
| { |
| /* 'clientp' points to the callback_data struct */ |
| /* investigate the situation and return the correct value */ |
| return CURLKHMATCH_OK; |
| } |
| { |
| curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/thisfile.txt"); |
| curl_easy_setopt(curl, CURLOPT_SSH_HOSTKEYFUNCTION, hostkeycb); |
| curl_easy_setopt(curl, CURLOPT_SSH_HOSTKEYDATA, &callback_data); |
| |
| curl_easy_perform(curl); |
| } |
| .fi |
| .SH AVAILABILITY |
| Added in 7.84.0 , work only with libssh2 backend. |
| .SH RETURN VALUE |
| Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. |
| .SH "SEE ALSO" |
| .BR CURLOPT_SSH_HOSTKEYDATA "(3), " |
| .BR CURLOPT_SSH_KNOWNHOSTS "(3), " |