bio_priv.h

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#pragma once
/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: 13908e0885c18cd435e43b77016349a51813c1b7 $
 * @file lib/bio/bio_priv.h
 * @brief Binary IO private functions
 *
 *  Create abstract binary input / output buffers.
 *
 * @copyright 2024 Network RADIUS SAS (legal@networkradius.com)
 */
RCSIDH(lib_bio_bio_priv_h, "$Id: 13908e0885c18cd435e43b77016349a51813c1b7 $")
 
#define _BIO_PRIVATE 1
#include <freeradius-devel/bio/base.h>
 
typedef struct fr_bio_common_s fr_bio_common_t;
 
typedef struct {
        fr_bio_io_t             connected;
        fr_bio_io_t             shutdown;
        fr_bio_io_t             eof;
        fr_bio_callback_t       failed;
 
        fr_bio_io_t             read_blocked;
        fr_bio_io_t             write_blocked;
 
        fr_bio_io_t             read_resume;            //!< "unblocked" is too similar to "blocked"
        fr_bio_io_t             write_resume;
} fr_bio_priv_callback_t;
 
/** Common elements at the start of each private #fr_bio_t
 *
 */
#define FR_BIO_COMMON \
        fr_bio_t                bio; \
        fr_bio_cb_funcs_t       cb; \
        fr_bio_priv_callback_t  priv_cb; \
        bool                    shutdown_pending        /*!< only meaningful on the head bio, see fr_bio_shutdown() */
 
struct fr_bio_common_s {
        FR_BIO_COMMON;
};
 
/** Define a common destructor pattern.
 *
 *  Ensure that talloc_free() is safe no matter what.  The caller can free any BIO at any time.  If that
 *  happens, then the entire chain is shut down.  On successful shutdown, this BIO is removed from the chain.
 */
#define FR_BIO_DESTRUCTOR_COMMON \
do { \
        if (my->priv_cb.shutdown) {                        \
                int rcode;                                 \
                /*                                         \
                 *      A free cannot wait for the application to drain any buffered data, so this \
                 *      tears the chain down now even if a shutdown was deferred.                  \
                 */                                        \
                rcode = fr_bio_shutdown_discard(&my->bio); \
                if (rcode < 0) return rcode;               \
        }                                                  \
        if (fr_bio_prev(&my->bio) || fr_bio_next(&my->bio)) \
                fr_bio_unchain(&my->bio);          \
} while (0)
 
 
ssize_t fr_bio_next_read(fr_bio_t *bio, void *packet_ctx, void *buffer, size_t size);
 
ssize_t fr_bio_next_write(fr_bio_t *bio, void *packet_ctx, void const *buffer, size_t size);
 
/** Chain one bio after another.
 *
 *  @todo - this likely needs to be public
 */
static inline void CC_HINT(nonnull) fr_bio_chain(fr_bio_t *first, fr_bio_t *second)
{
        fr_assert(first->entry.prev == NULL);
        fr_assert(first->entry.next == NULL);
 
        fr_assert(second->entry.prev == NULL);
 
        first->entry.next = &second->entry;
        second->entry.prev = &first->entry;
}
 
/** Remove a bio from a chain
 *
 *  And reset prev/next ptrs to NULL.
 *
 *  @todo - this likely needs to be public
 */
static inline void CC_HINT(nonnull) fr_bio_unchain(fr_bio_t *bio)
{
        fr_bio_t *prev = fr_bio_prev(bio);
        fr_bio_t *next = fr_bio_next(bio);
 
        fr_assert(prev || next);
 
        if (prev) prev->entry.next = bio->entry.next;
 
        if (next) next->entry.prev = bio->entry.prev;
 
        bio->entry.prev = bio->entry.next = NULL;
}
 
/** Tell the chain that a bio is at EOF, and let the application drain whatever is buffered.
 *
 *  @return
 *      - NULL if every bio in the chain is at EOF
 *      - the bio which still holds data, and which therefore stopped the walk
 */
fr_bio_t *fr_bio_eof(fr_bio_t *bio) CC_HINT(nonnull);
 
int     fr_bio_write_blocked(fr_bio_t *bio) CC_HINT(nonnull);