a58eb06d52
OpenSSL already has the feature of SSL_MODE_RELEASE_BUFFERS that can be set to release the read or write buffers when data has finished reading or writing. OpenSSL will automatically re-allocate the buffers as needed. This can be quite aggressive in terms of memory allocation. This provides a manual mechanism. SSL_free_buffers() will free the data buffers if there's no pending data. SSL_alloc_buffers() will realloc them; but this function is not strictly necessary, as it's still done automatically in the state machine. Reviewed-by: Richard Levitte <levitte@openssl.org> Reviewed-by: Rich Salz <rsalz@openssl.org> (Merged from https://github.com/openssl/openssl/pull/2240)
67 lines
2 KiB
Text
67 lines
2 KiB
Text
=pod
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=head1 NAME
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SSL_free_buffers, SSL_alloc_buffers - manage SSL structure buffers
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=head1 SYNOPSIS
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#include <openssl/ssl.h>
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int SSL_free_buffers(SSL *ssl);
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int SSL_alloc_buffers(SSL *ssl);
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=head1 DESCRIPTION
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SSL_free_buffers() frees the read and write buffers of the given B<ssl>.
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SSL_alloc_buffers() allocates the read and write buffers of the given B<ssl>.
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The B<SSL_MODE_RELEASE_BUFFERS> mode releases read or write buffers whenever
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the buffers have been drained. These functions allow applications to manually
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control when buffers are freed and allocated.
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After freeing the buffers, the buffers are automatically reallocted upon a
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new read or write. The SSL_alloc_buffers() does not need to be called, but
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can be used to make sure the buffers are pre-allocated. This can be used to
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avoid allocation during data processing or with CRYPTO_set_mem_functions()
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to control where and how buffers are allocated.
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=head1 RETURN VALUES
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The following return values can occur:
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=over 4
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=item 0 (Failure)
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The SSL_free_buffers() function returns 0 when there is pending data to be
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read or written. The SSL_alloc_buffers() function returns 0 when there is
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an allocation failure.
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=item 1 (Success)
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The SSL_free_buffers() function returns 1 if the buffers have been freed. This
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value is also returned if the buffers had been freed before calling
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SSL_free_buffers().
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The SSL_alloc_buffers() function returns 1 if the buffers have been allocated.
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This valus is also returned if the buffers had been allocated before calling
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SSL_alloc_buffers().
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=back
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=head1 SEE ALSO
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L<SSL_free(3)>, L<SSL_clear(3)>,
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L<SSL_new(3)>, L<SSL_CTX_set_mode(3)>,
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L<CRYPTO_set_mem_functions>
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=head1 COPYRIGHT
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Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the OpenSSL license (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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