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@@ -2,82 +2,100 @@
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=head1 NAME
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-SSL_read - read bytes from a TLS/SSL connection
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+SSL_read_ex, SSL_read - read bytes from a TLS/SSL connection
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=head1 SYNOPSIS
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#include <openssl/ssl.h>
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+ int SSL_read_ex(SSL *ssl, void *buf, size_t num, size_t *read);
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int SSL_read(SSL *ssl, void *buf, int num);
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+ int SSL_peek_ex(SSL *ssl, void *buf, size_t num, size_t *read);
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+ int SSL_peek(SSL *ssl, void *buf, int num);
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+
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=head1 DESCRIPTION
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-SSL_read() tries to read B<num> bytes from the specified B<ssl> into the
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-buffer B<buf>.
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+SSL_read_ex() and SSL_read() try to read B<num> bytes from the specified B<ssl>
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+into the buffer B<buf>. On success SSL_read_ex() will store the number of bytes
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+actually read in B<*read>.
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+
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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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=head1 NOTES
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-If necessary, SSL_read() will negotiate a TLS/SSL session, if
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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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+
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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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peer requests a re-negotiation, it will be performed transparently during
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-the SSL_read() operation. The behaviour of SSL_read() depends on the
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-underlying BIO.
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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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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() or L<SSL_write(3)>
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-function.
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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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-SSL_read() works based on the SSL/TLS records. The data are received in
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-records (with a maximum record size of 16kB for SSLv3/TLSv1). Only when a
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-record has been completely received, it can be processed (decryption and
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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() can still be buffered inside the SSL layer and will be
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-retrieved on the next call to SSL_read(). If B<num> is higher than the
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-number of bytes buffered, SSL_read() will return with the bytes buffered.
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-If no more bytes are in the buffer, SSL_read() will trigger the processing
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-of the next record. Only when the record has been received and processed
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-completely, SSL_read() will return reporting success. At most the contents
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-of the record will be returned. As the size of an SSL/TLS record may exceed
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-the maximum packet size of the underlying transport (e.g. TCP), it may
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-be necessary to read several packets from the transport layer before the
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-record is complete and SSL_read() can succeed.
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-
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-If the underlying BIO is B<blocking>, SSL_read() 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 take place, in which case a SSL_ERROR_WANT_READ may occur.
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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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+can succeed.
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+
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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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L<SSL_CTX_set_mode(3)> call.
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-If the underlying BIO is B<non-blocking>, SSL_read() will also return
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-when the underlying BIO could not satisfy the needs of SSL_read()
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-to continue the operation. In this case a call to
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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() will yield B<SSL_ERROR_WANT_READ> or
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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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B<SSL_ERROR_WANT_WRITE>. As at any time a re-negotiation is possible, a
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-call to SSL_read() can also cause write operations! The calling process
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-then must repeat the call after taking appropriate action to satisfy the
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-needs of SSL_read(). The action depends on the underlying BIO. When using a
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-non-blocking socket, nothing is to be done, but select() can be used to check
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-for the required condition. When using a buffering BIO, like a BIO pair, data
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-must be written into or retrieved out of the BIO before being able to continue.
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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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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() can be called without blocking or actually receiving new
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-data from the underlying socket.
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+SSL_read_ex() or SSL_read() 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() operation has to be repeated because of
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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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with the same arguments.
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=head1 RETURN VALUES
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-The following return values can occur:
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+SSL_read_ex() will return 1 for success or 0 for failure. In the event of a
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+failure call SSL_get_error() to find out the reason.
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+
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+For SSL_read() the following return values can occur:
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=over 4
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@@ -108,7 +126,7 @@ return value B<ret> to find out the reason.
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=head1 SEE ALSO
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-L<SSL_get_error(3)>, L<SSL_write(3)>,
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+L<SSL_get_error(3)>, L<SSL_write_ex(3)>,
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L<SSL_CTX_set_mode(3)>, L<SSL_CTX_new(3)>,
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L<SSL_connect(3)>, L<SSL_accept(3)>
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L<SSL_set_connect_state(3)>,
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