DragonFly On-Line Manual Pages
BIO(3) DragonFly Library Functions Manual BIO(3)
NAME
BIO -- I/O abstraction
SYNOPSIS
#include <openssl/bio.h>
DESCRIPTION
A BIO is an I/O abstraction, it hides many of the underlying I/O details
from an application. If an application uses a BIO for its I/O, it can
transparently handle SSL connections, unencrypted network connections and
file I/O.
There are two types of BIO, a source/sink BIO and a filter BIO.
As its name implies, a source/sink BIO is a source and/or sink of data,
examples include a socket BIO and a file BIO.
A filter BIO takes data from one BIO and passes it through to another, or
to the application. The data may be left unmodified (for example a mes-
sage digest BIO) or translated (for example an encryption BIO). The
effect of a filter BIO may change according to the I/O operation it is
performing: for example an encryption BIO will encrypt data if it is
being written to and decrypt data if it is being read from.
BIOs can be joined together to form a chain (a single BIO is a chain with
one component). A chain normally consist of one source/sink BIO and one
or more filter BIOs. Data read from or written to the first BIO then
traverses the chain to the end (normally a source/sink BIO).
SEE ALSO
BIO_ctrl(3), BIO_f_base64(3), BIO_f_buffer(3), BIO_f_cipher(3),
BIO_f_md(3), BIO_f_null(3), BIO_f_ssl(3), BIO_find_type(3), BIO_new(3),
BIO_new_bio_pair(3), BIO_push(3), BIO_read(3), BIO_s_accept(3),
BIO_s_bio(3), BIO_s_connect(3), BIO_s_fd(3), BIO_s_file(3), BIO_s_mem(3),
BIO_s_null(3), BIO_s_socket(3), BIO_set_callback(3), BIO_should_retry(3)
DragonFly 4.7 July 17, 2014 DragonFly 4.7
BIO_find_type(3) OpenSSL BIO_find_type(3)
NAME
BIO_find_type, BIO_next, BIO_method_type - BIO chain traversal
SYNOPSIS
#include <openssl/bio.h>
BIO * BIO_find_type(BIO *b,int bio_type);
BIO * BIO_next(BIO *b);
#define BIO_method_type(b) ((b)->method->type)
#define BIO_TYPE_NONE 0
#define BIO_TYPE_MEM (1|0x0400)
#define BIO_TYPE_FILE (2|0x0400)
#define BIO_TYPE_FD (4|0x0400|0x0100)
#define BIO_TYPE_SOCKET (5|0x0400|0x0100)
#define BIO_TYPE_NULL (6|0x0400)
#define BIO_TYPE_SSL (7|0x0200)
#define BIO_TYPE_MD (8|0x0200)
#define BIO_TYPE_BUFFER (9|0x0200)
#define BIO_TYPE_CIPHER (10|0x0200)
#define BIO_TYPE_BASE64 (11|0x0200)
#define BIO_TYPE_CONNECT (12|0x0400|0x0100)
#define BIO_TYPE_ACCEPT (13|0x0400|0x0100)
#define BIO_TYPE_PROXY_CLIENT (14|0x0200)
#define BIO_TYPE_PROXY_SERVER (15|0x0200)
#define BIO_TYPE_NBIO_TEST (16|0x0200)
#define BIO_TYPE_NULL_FILTER (17|0x0200)
#define BIO_TYPE_BER (18|0x0200)
#define BIO_TYPE_BIO (19|0x0400)
#define BIO_TYPE_DESCRIPTOR 0x0100
#define BIO_TYPE_FILTER 0x0200
#define BIO_TYPE_SOURCE_SINK 0x0400
DESCRIPTION
The BIO_find_type() searches for a BIO of a given type in a chain,
starting at BIO b. If type is a specific type (such as BIO_TYPE_MEM)
then a search is made for a BIO of that type. If type is a general type
(such as BIO_TYPE_SOURCE_SINK) then the next matching BIO of the given
general type is searched for. BIO_find_type() returns the next matching
BIO or NULL if none is found.
Note: not all the BIO_TYPE_* types above have corresponding BIO
implementations.
BIO_next() returns the next BIO in a chain. It can be used to traverse
all BIOs in a chain or used in conjunction with BIO_find_type() to find
all BIOs of a certain type.
BIO_method_type() returns the type of a BIO.
RETURN VALUES
BIO_find_type() returns a matching BIO or NULL for no match.
BIO_next() returns the next BIO in a chain.
BIO_method_type() returns the type of the BIO b.
NOTES
BIO_next() was added to OpenSSL 0.9.6 to provide a 'clean' way to
traverse a BIO chain or find multiple matches using BIO_find_type().
Previous versions had to use:
next = bio->next_bio;
BUGS
BIO_find_type() in OpenSSL 0.9.5a and earlier could not be safely
passed a NULL pointer for the b argument.
EXAMPLE
Traverse a chain looking for digest BIOs:
BIO *btmp;
btmp = in_bio; /* in_bio is chain to search through */
do {
btmp = BIO_find_type(btmp, BIO_TYPE_MD);
if(btmp == NULL) break; /* Not found */
/* btmp is a digest BIO, do something with it ...*/
...
btmp = BIO_next(btmp);
} while(btmp);
SEE ALSO
TBA
1.0.2h 2016-05-03 BIO_find_type(3)