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@@ -23,71 +23,66 @@ actually read in B<*read>.
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SSL_peek_ex() and SSL_peek() are identical to SSL_read_ex() and SSL_read()
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respectively except no bytes are actually removed from the underlying BIO during
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the read, so that a subsequent call to SSL_read_ex() or SSL_read() will yield
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-the same bytes.
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+at least the same bytes.
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=head1 NOTES
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-In this notes section all comments that apply to SSL_read_ex() or SSL_read()
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-also apply to SSL_peek_ex() and SSL_peek().
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+In the paragraphs below a "read function" is defined as one of SSL_read_ex(),
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+SSL_read(), SSL_peek_ex() or SSL_peek().
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-If necessary, SSL_read_ex() or SSL_read() will negotiate a TLS/SSL session, if
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-not already explicitly performed by L<SSL_connect(3)> or
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-L<SSL_accept(3)>. If the
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+If necessary, a read function will negotiate a TLS/SSL session, if not already
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+explicitly performed by L<SSL_connect(3)> or L<SSL_accept(3)>. If the
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peer requests a re-negotiation, it will be performed transparently during
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-the SSL_read_ex() or SSL_read() operation. The behaviour of SSL_read_ex() and
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-SSL_read() depends on the underlying BIO.
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+the read function operation. The behaviour of the read functions depends on the
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+underlying BIO.
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For the transparent negotiation to succeed, the B<ssl> must have been
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initialized to client or server mode. This is being done by calling
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-L<SSL_set_connect_state(3)> or SSL_set_accept_state()
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-before the first call to an SSL_read_ex(), SSL_read(), L<SSL_write_ex(3)> or
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-L<SSL_write(3)> function.
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-
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-SSL_read_ex() and SSL_read() work based on the SSL/TLS records. The data are
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-received in records (with a maximum record size of 16kB for SSLv3/TLSv1). Only
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-when a record has been completely received, it can be processed (decryption and
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-check of integrity). Therefore data that was not retrieved at the last
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-call of SSL_read_ex() or SSL_read() can still be buffered inside the SSL layer
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-and will be retrieved on the next call to SSL_read_ex() or SSL_read(). If B<num>
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-is higher than the number of bytes buffered, SSL_read_ex() or SSL_read() will
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-return with the bytes buffered. If no more bytes are in the buffer, SSL_read()
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-will trigger the processing of the next record. Only when the record has been
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-received and processed completely, SSL_read_ex() or SSL_read() will return
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-reporting success. At most the contents of the record will be returned. As the
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-size of an SSL/TLS record may exceed the maximum packet size of the underlying
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-transport (e.g. TCP), it may be necessary to read several packets from the
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-transport layer before the record is complete and SSL_read_ex() or SSL_read()
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+L<SSL_set_connect_state(3)> or SSL_set_accept_state() before the first
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+invocation of a read function.
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+
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+The read functions work based on the SSL/TLS records. The data are received in
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+records (with a maximum record size of 16kB). Only when a record has been
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+completely received, can it be processed (decryption and check of integrity).
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+Therefore data that was not retrieved at the last read call can still be
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+buffered inside the SSL layer and will be retrieved on the next read
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+call. If B<num> is higher than the number of bytes buffered then the read
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+functions will return with the bytes buffered. If no more bytes are in the
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+buffer, the read functions will trigger the processing of the next record.
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+Only when the record has been received and processed completely will the read
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+functions return reporting success. At most the contents of the record will
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+be returned. As the size of an SSL/TLS record may exceed the maximum packet size
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+of the underlying transport (e.g. TCP), it may be necessary to read several
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+packets from the transport layer before the record is complete and the read call
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can succeed.
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-If the underlying BIO is B<blocking>, SSL_read_ex() or SSL_read() will only
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-return, once the read operation has been finished or an error occurred, except
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-when a renegotiation take place, in which case a SSL_ERROR_WANT_READ may occur.
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-This behaviour can be controlled with the SSL_MODE_AUTO_RETRY flag of the
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+If the underlying BIO is B<blocking>, a read function will only return once the
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+read operation has been finished or an error occurred, except when a
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+renegotiation takes place, in which case a SSL_ERROR_WANT_READ may occur. This
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+behaviour can be controlled with the SSL_MODE_AUTO_RETRY flag of the
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L<SSL_CTX_set_mode(3)> call.
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-If the underlying BIO is B<non-blocking>, SSL_read_ex() or SSL_read() will also
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-return when the underlying BIO could not satisfy the needs of SSL_read_ex() or
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-SSL_read() to continue the operation. In this case a call to
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-L<SSL_get_error(3)> with the
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-return value of SSL_read_ex() or SSL_read() will yield B<SSL_ERROR_WANT_READ> or
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+If the underlying BIO is B<non-blocking>, a read function will also return when
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+the underlying BIO could not satisfy the needs of the function to continue the
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+operation. In this case a call to L<SSL_get_error(3)> with the
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+return value of the read function will yield B<SSL_ERROR_WANT_READ> or
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B<SSL_ERROR_WANT_WRITE>. As at any time a re-negotiation is possible, a
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-call to SSL_read_ex() or SSL_read() can also cause write operations! The calling
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-process then must repeat the call after taking appropriate action to satisfy the
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-needs of SSL_read_ex() or SSL_read(). The action depends on the underlying BIO.
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-When using a non-blocking socket, nothing is to be done, but select() can be
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-used to check for the required condition. When using a buffering BIO, like a
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-BIO pair, data must be written into or retrieved out of the BIO before being
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-able to continue.
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+a read function can also cause write operations! The calling process then must
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+repeat the call after taking appropriate action to satisfy the needs of the read
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+function. The action depends on the underlying BIO. When using a non-blocking
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+socket, nothing is to be done, but select() can be used to check for the
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+required condition. When using a buffering BIO, like a BIO pair, data must be
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+written into or retrieved out of the BIO before being able to continue.
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L<SSL_pending(3)> can be used to find out whether there
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are buffered bytes available for immediate retrieval. In this case
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-SSL_read_ex() or SSL_read() can be called without blocking or actually receiving
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+the read function can be called without blocking or actually receiving
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new data from the underlying socket.
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=head1 WARNING
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-When an SSL_read_ex() or SSL_read() operation has to be repeated because of
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-B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>, it must be repeated
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+When a read function operation has to be repeated because L<SSL_get_error(3)>
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+returned B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>, it must be repeated
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with the same arguments.
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=head1 RETURN VALUES
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