SSL_connect.pod 2.5 KB

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  1. =pod
  2. =head1 NAME
  3. SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server
  4. =head1 SYNOPSIS
  5. #include <openssl/ssl.h>
  6. int SSL_connect(SSL *ssl);
  7. =head1 DESCRIPTION
  8. SSL_connect() initiates the TLS/SSL handshake with a server. The communication
  9. channel must already have been set and assigned to the B<ssl> by setting an
  10. underlying B<BIO>.
  11. =head1 NOTES
  12. The behaviour of SSL_connect() depends on the underlying BIO.
  13. If the underlying BIO is B<blocking>, SSL_connect() will only return once the
  14. handshake has been finished or an error occurred.
  15. If the underlying BIO is B<non-blocking>, SSL_connect() will also return
  16. when the underlying BIO could not satisfy the needs of SSL_connect()
  17. to continue the handshake, indicating the problem by the return value -1.
  18. In this case a call to SSL_get_error() with the
  19. return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or
  20. B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
  21. taking appropriate action to satisfy the needs of SSL_connect().
  22. The action depends on the underlying BIO. When using a non-blocking socket,
  23. nothing is to be done, but select() can be used to check for the required
  24. condition. When using a buffering BIO, like a BIO pair, data must be written
  25. into or retrieved out of the BIO before being able to continue.
  26. =head1 RETURN VALUES
  27. The following return values can occur:
  28. =over 4
  29. =item Z<>0
  30. The TLS/SSL handshake was not successful but was shut down controlled and
  31. by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the
  32. return value B<ret> to find out the reason.
  33. =item Z<>1
  34. The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
  35. established.
  36. =item E<lt>0
  37. The TLS/SSL handshake was not successful, because a fatal error occurred either
  38. at the protocol level or a connection failure occurred. The shutdown was
  39. not clean. It can also occur of action is need to continue the operation
  40. for non-blocking BIOs. Call SSL_get_error() with the return value B<ret>
  41. to find out the reason.
  42. =back
  43. =head1 SEE ALSO
  44. L<SSL_get_error(3)>, L<SSL_accept(3)>,
  45. L<SSL_shutdown(3)>, L<ssl(7)>, L<bio(7)>,
  46. L<SSL_set_connect_state(3)>,
  47. L<SSL_do_handshake(3)>,
  48. L<SSL_CTX_new(3)>
  49. =head1 COPYRIGHT
  50. Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
  51. Licensed under the OpenSSL license (the "License"). You may not use
  52. this file except in compliance with the License. You can obtain a copy
  53. in the file LICENSE in the source distribution or at
  54. L<https://www.openssl.org/source/license.html>.
  55. =cut