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