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Diffstat (limited to 'doc/crypto/BIO_new_bio_pair.pod')
| -rw-r--r-- | doc/crypto/BIO_new_bio_pair.pod | 103 |
1 files changed, 0 insertions, 103 deletions
diff --git a/doc/crypto/BIO_new_bio_pair.pod b/doc/crypto/BIO_new_bio_pair.pod deleted file mode 100644 index 1a8dbc577b..0000000000 --- a/doc/crypto/BIO_new_bio_pair.pod +++ /dev/null @@ -1,103 +0,0 @@ -=pod - -=head1 NAME - -BIO_new_bio_pair - create a new BIO pair - -=head1 SYNOPSIS - - #include <openssl/bio.h> - - int BIO_new_bio_pair(BIO **bio1, size_t writebuf1, BIO **bio2, size_t writebuf2); - -=head1 DESCRIPTION - -BIO_new_bio_pair() creates a buffering BIO pair based on the -L<SSL_set_bio(3)|SSL_set_bio(3)> method. The BIO pair has two endpoints between which -data can be buffered. Its typical use is to connect one endpoint as underlying -input/output BIO to an SSL and access the other one controlled by the program -instead of accessing the network connection directly. - -The two new BIOs B<bio1> and B<bio2> are symmetric with respect to their -functionality. The size of their buffers is determined by B<writebuf1> and -B<writebuf2>. If the size give is 0, the default size is used. - -BIO_new_bio_pair() does not check whether B<bio1> or B<bio2> do point to -some other BIO, the values are overwritten, BIO_free() is not called. - -The two BIOs, even though forming a BIO pair and must be BIO_free()'ed -separately. This can be of importance, as some SSL-functions like SSL_set_bio() -or SSL_free() call BIO_free() implicitly, so that the peer-BIO is left -untouched and must also be BIO_free()'ed. - -=head1 EXAMPLE - -The BIO pair can be used to have full control over the network access of an -application. The application can call select() on the socket as required -without having to go through the SSL-interface. - - BIO *internal_bio, *network_bio; - ... - BIO_new_bio_pair(internal_bio, 0, network_bio, 0); - SSL_set_bio(ssl, internal_bio, internal_bio); - SSL_operations(); - ... - - application | TLS-engine - | | - +----------> SSL_operations() - | /\ || - | || \/ - | BIO-pair (internal_bio) - +----------< BIO-pair (network_bio) - | | - socket | - - ... - SSL_free(ssl); /* implicitly frees internal_bio */ - BIO_free(network_bio); - ... - -As the BIO pair will only buffer the data and never directly access the -connection, it behaves non-blocking and will return as soon as the write -buffer is full or the read buffer is drained. Then the application has to -flush the write buffer and/or fill the read buffer. - -Use the BIO_ctrl_pending(), to find out whether data is buffered in the BIO -and must be transfered to the network. Use BIO_ctrl_get_read_request() to -find out, how many bytes must be written into the buffer before the -SSL_operation() can successfully be continued. - -=head1 WARNING - -As the data is buffered, SSL_operation() may return with a ERROR_SSL_WANT_READ -condition, but there is still data in the write buffer. An application must -not rely on the error value of SSL_operation() but must assure that the -write buffer is always flushed first. Otherwise a deadlock may occur as -the peer might be waiting for the data before being able to continue. - -=head1 RETURN VALUES - -The following return values can occur: - -=over 4 - -=item 1 - -The BIO pair was created successfully. The new BIOs are available in -B<bio1> and B<bio2>. - -=item 0 - -The operation failed. The NULL pointer is stored into the locations for -B<bio1> and B<bio2>. Check the error stack for more information. - -=back - -=head1 SEE ALSO - -L<SSL_set_bio(3)|SSL_set_bio(3)>, L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>, -L<BIO_ctrl_pending(3)|BIO_ctrl_pending(3)>, -L<BIO_ctrl_get_read_request(3)|BIO_ctrl_get_read_request(3)> - -=cut |