1=pod
2
3=head1 NAME
4
5BIO_find_type, BIO_next - BIO chain traversal
6
7=head1 SYNOPSIS
8
9 #include <openssl/bio.h>
10
11 BIO *	BIO_find_type(BIO *b,int bio_type);
12 BIO *	BIO_next(BIO *b);
13
14 #define BIO_method_type(b)		((b)->method->type)
15
16 #define BIO_TYPE_NONE		0
17 #define BIO_TYPE_MEM		(1|0x0400)
18 #define BIO_TYPE_FILE		(2|0x0400)
19
20 #define BIO_TYPE_FD		(4|0x0400|0x0100)
21 #define BIO_TYPE_SOCKET		(5|0x0400|0x0100)
22 #define BIO_TYPE_NULL		(6|0x0400)
23 #define BIO_TYPE_SSL		(7|0x0200)
24 #define BIO_TYPE_MD		(8|0x0200)
25 #define BIO_TYPE_BUFFER		(9|0x0200)
26 #define BIO_TYPE_CIPHER		(10|0x0200)
27 #define BIO_TYPE_BASE64		(11|0x0200)
28 #define BIO_TYPE_CONNECT	(12|0x0400|0x0100)
29 #define BIO_TYPE_ACCEPT		(13|0x0400|0x0100)
30 #define BIO_TYPE_PROXY_CLIENT	(14|0x0200)
31 #define BIO_TYPE_PROXY_SERVER	(15|0x0200)
32 #define BIO_TYPE_NBIO_TEST	(16|0x0200)
33 #define BIO_TYPE_NULL_FILTER	(17|0x0200)
34 #define BIO_TYPE_BER		(18|0x0200)
35 #define BIO_TYPE_BIO		(19|0x0400)
36
37 #define BIO_TYPE_DESCRIPTOR	0x0100
38 #define BIO_TYPE_FILTER		0x0200
39 #define BIO_TYPE_SOURCE_SINK	0x0400
40
41=head1 DESCRIPTION
42
43The BIO_find_type() searches for a BIO of a given type in a chain, starting
44at BIO B<b>. If B<type> is a specific type (such as BIO_TYPE_MEM) then a search
45is made for a BIO of that type. If B<type> is a general type (such as
46B<BIO_TYPE_SOURCE_SINK>) then the next matching BIO of the given general type is
47searched for. BIO_find_type() returns the next matching BIO or NULL if none is
48found.
49
50Note: not all the B<BIO_TYPE_*> types above have corresponding BIO implementations.
51
52BIO_next() returns the next BIO in a chain. It can be used to traverse all BIOs
53in a chain or used in conjunction with BIO_find_type() to find all BIOs of a
54certain type.
55
56BIO_method_type() returns the type of a BIO.
57
58=head1 RETURN VALUES
59
60BIO_find_type() returns a matching BIO or NULL for no match.
61
62BIO_next() returns the next BIO in a chain.
63
64BIO_method_type() returns the type of the BIO B<b>.
65
66=head1 NOTES
67
68BIO_next() was added to OpenSSL 0.9.6 to provide a 'clean' way to traverse a BIO
69chain or find multiple matches using BIO_find_type(). Previous versions had to
70use:
71
72 next = bio->next_bio;
73
74=head1 BUGS
75
76BIO_find_type() in OpenSSL 0.9.5a and earlier could not be safely passed a
77NULL pointer for the B<b> argument.
78
79=head1 EXAMPLE
80
81Traverse a chain looking for digest BIOs:
82
83 BIO *btmp;
84 btmp = in_bio;	/* in_bio is chain to search through */
85
86 do {
87 	btmp = BIO_find_type(btmp, BIO_TYPE_MD);
88	if(btmp == NULL) break;	/* Not found */
89	/* btmp is a digest BIO, do something with it ...*/
90   	...
91
92	btmp = BIO_next(btmp);
93 } while(btmp);
94
95
96=head1 SEE ALSO
97
98TBA
99