diff options
author | Rich Salz <rsalz@openssl.org> | 2016-10-26 13:56:48 -0400 |
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committer | Rich Salz <rsalz@openssl.org> | 2016-10-26 13:59:52 -0400 |
commit | 99d63d4662e16afbeff49f29b48f1c87d5558ed0 (patch) | |
tree | 6512ff02cd93985526080f05ab2b5408235b19a9 /doc/man3/SSL_write.pod | |
parent | 4f3015bb30b7d95bb97408776b70e6a35fb91e8a (diff) |
Move manpages to man[1357] structure.
Move manpages to manX directories
Add Windows/VMS install fix from Richard Levitte
Update README
Fix typo's
Remove some duplicates
Reviewed-by: Richard Levitte <levitte@openssl.org>
Diffstat (limited to 'doc/man3/SSL_write.pod')
-rw-r--r-- | doc/man3/SSL_write.pod | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/doc/man3/SSL_write.pod b/doc/man3/SSL_write.pod new file mode 100644 index 0000000000..5ab079042e --- /dev/null +++ b/doc/man3/SSL_write.pod @@ -0,0 +1,114 @@ +=pod + +=head1 NAME + +SSL_write - write bytes to a TLS/SSL connection + +=head1 SYNOPSIS + + #include <openssl/ssl.h> + + int SSL_write(SSL *ssl, const void *buf, int num); + +=head1 DESCRIPTION + +SSL_write() writes B<num> bytes from the buffer B<buf> into the specified +B<ssl> connection. + +=head1 NOTES + +If necessary, SSL_write() will negotiate a TLS/SSL session, if +not already explicitly performed by L<SSL_connect(3)> or +L<SSL_accept(3)>. If the +peer requests a re-negotiation, it will be performed transparently during +the SSL_write() operation. The behaviour of SSL_write() depends on the +underlying BIO. + +For the transparent negotiation to succeed, the B<ssl> must have been +initialized to client or server mode. This is being done by calling +L<SSL_set_connect_state(3)> or SSL_set_accept_state() +before the first call to an L<SSL_read(3)> or SSL_write() function. + +If the underlying BIO is B<blocking>, SSL_write() will only return, once the +write operation has been finished or an error occurred, except when a +renegotiation take place, in which case a SSL_ERROR_WANT_READ may occur. +This behaviour can be controlled with the SSL_MODE_AUTO_RETRY flag of the +L<SSL_CTX_set_mode(3)> call. + +If the underlying BIO is B<non-blocking>, SSL_write() will also return, +when the underlying BIO could not satisfy the needs of SSL_write() +to continue the operation. In this case a call to +L<SSL_get_error(3)> with the +return value of SSL_write() will yield B<SSL_ERROR_WANT_READ> or +B<SSL_ERROR_WANT_WRITE>. As at any time a re-negotiation is possible, a +call to SSL_write() can also cause read operations! The calling process +then must repeat the call after taking appropriate action to satisfy the +needs of SSL_write(). The action depends on the underlying BIO. When using a +non-blocking socket, nothing is to be done, but select() can be used to check +for the required condition. When using a buffering BIO, like a BIO pair, data +must be written into or retrieved out of the BIO before being able to continue. + +SSL_write() will only return with success, when the complete contents +of B<buf> of length B<num> has been written. This default behaviour +can be changed with the SSL_MODE_ENABLE_PARTIAL_WRITE option of +L<SSL_CTX_set_mode(3)>. When this flag is set, +SSL_write() will also return with success, when a partial write has been +successfully completed. In this case the SSL_write() operation is considered +completed. The bytes are sent and a new SSL_write() operation with a new +buffer (with the already sent bytes removed) must be started. +A partial write is performed with the size of a message block, which is +16kB for SSLv3/TLSv1. + +=head1 WARNING + +When an SSL_write() operation has to be repeated because of +B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>, it must be repeated +with the same arguments. + +When calling SSL_write() with num=0 bytes to be sent the behaviour is +undefined. + +=head1 RETURN VALUES + +The following return values can occur: + +=over 4 + +=item E<gt>0 + +The write operation was successful, the return value is the number of +bytes actually written to the TLS/SSL connection. + +=item Z<>0 + +The write operation was not successful. Probably the underlying connection +was closed. Call SSL_get_error() with the return value B<ret> to find out, +whether an error occurred or the connection was shut down cleanly +(SSL_ERROR_ZERO_RETURN). + +=item E<lt>0 + +The write operation was not successful, because either an error occurred +or action must be taken by the calling process. Call SSL_get_error() with the +return value B<ret> to find out the reason. + +=back + +=head1 SEE ALSO + +L<SSL_get_error(3)>, L<SSL_read(3)>, +L<SSL_CTX_set_mode(3)>, L<SSL_CTX_new(3)>, +L<SSL_connect(3)>, L<SSL_accept(3)> +L<SSL_set_connect_state(3)>, +L<ssl(3)>, L<bio(3)> + +=head1 COPYRIGHT + +Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (the "License"). You may not use +this file except in compliance with the License. You can obtain a copy +in the file LICENSE in the source distribution or at +L<https://www.openssl.org/source/license.html>. + +=cut |