ber_sockbuf_alloc, ber_sockbuf_free, ber_sockbuf_ctrl, ber_sockbuf_add_io, ber_sockbuf_remove_io, Sockbuf_IO — OpenLDAP LBER I/O infrastructure
#include <lber.h>
Sockbuf
*fsfuncber_sockbuf_alloc( |
void); |
void
fsfuncber_sockbuf_free( |
Sockbuf *sb); |
int
fsfuncber_sockbuf_ctrl( |
Sockbuf *sb, |
| int opt, | |
void *arg); |
int
fsfuncber_sockbuf_add_io( |
Sockbuf *sb, |
| Sockbuf_IO *sbio, | |
| int layer, | |
void *arg); |
int
fsfuncber_sockbuf_remove_io( |
Sockbuf *sb, |
| Sockbuf_IO *sbio, | |
int layer); |
| typedef | struct sockbuf_io_desc { | |||
| int | sbiod_level; |
|||
| Sockbuf | * | sbiod_sb; |
||
| Sockbuf_IO | * | sbiod_io; |
||
| void | * | sbiod_pvt; |
||
| struct sockbuf_io_desc | * | sbiod_next; |
||
| } Sockbuf_IO_Desc; | ||||
| typedef | struct sockbuf_io { | |||
| int | (* | sbi_setup)(Sockbuf_IO_Desc *sbiod, void *arg); |
||
| int | (* | sbi_remove)(Sockbuf_IO_Desc *sbiod); |
||
| int | (* | sbi_ctrl)(Sockbuf_IO_Desc *sbiod, int opt, void *arg); |
||
| ber_slen_t | (* | sbi_read)(Sockbuf_IO_Desc *sbiod, void *buf, ber_len_t len); |
||
| ber_slen_t | (* | sbi_write)(Sockbuf_IO_Desc *sbiod, void *buf, ber_len_t len); |
||
| int | (* | sbi_close)(Sockbuf_IO_Desc *sbiod); |
||
| } Sockbuf_IO; | ||||
These routines are used to manage the low level I/O
operations performed by the Lightweight BER library. They are
called implicitly by the other libraries and usually do not
need to be called directly from applications. The I/O
framework is modularized and new transport layers can be
supported by appropriately defining a Sockbuf_IO structure and installing it
onto an existing Sockbuf.
Sockbuf structures are
allocated and freed by ber_sockbuf_alloc() and ber_sockbuf_free(), respectively. The
ber_sockbuf_ctrl() function is
used to get and set options related to a Sockbuf or to a specific I/O layer of the
Sockbuf. The ber_sockbuf_add_io() and ber_sockbuf_remove_io() functions are used
to add and remove specific I/O layers on a Sockbuf.
Options for ber_sockbuf_ctrl() include:
LBER_SB_OPT_HAS_IOTakes a Sockbuf_IO * argument and returns 1 if the given handler is installed on the Sockbuf, otherwise returns 0.
LBER_SB_OPT_GET_FDRetrieves the file descriptor associated to the
Sockbuf; arg must be a
ber_socket_t *.
The return value will be 1 if a valid descriptor was
present, −1 otherwise.
LBER_SB_OPT_SET_FDSets the file descriptor of the Sockbuf to the descriptor pointed
to by arg;
arg must be a
ber_socket_t *.
The return value will always be 1.
LBER_SB_OPT_SET_NONBLOCKToggles the non-blocking state of the file
descriptor associated to the Sockbuf. arg should be NULL to
disable and non-NULL to enable the non-blocking state.
The return value will be 1 for success, −1
otherwise.
LBER_SB_OPT_DRAINFlush (read and discard) all available input on the Sockbuf. The return value will be 1.
LBER_SB_OPT_NEEDS_READReturns non-zero if input is waiting to be read.
LBER_SB_OPT_NEEDS_WRITEReturns non-zero if the Sockbuf is ready to be written.
LBER_SB_OPT_GET_MAX_INCOMINGReturns the maximum allowed size of an incoming
message; arg
must be a ber_len_t
*. The return value will be 1.
LBER_SB_OPT_SET_MAX_INCOMINGSets the maximum allowed size of an incoming
message; arg
must be a ber_len_t
*. The return value will be 1.
Options not in this list will be passed down to each
Sockbuf_IO handler in
turn until one of them processes it. If the option is
not handled ber_sockbuf_ctrl() will return 0.
Multiple Sockbuf_IO handlers can be stacked in multiple layers to provide various functionality. Currently defined layers include
LBER_SBIOD_LEVEL_PROVIDERthe lowest layer, talking directly to a network
LBER_SBIOD_LEVEL_TRANSPORTan intermediate layer
LBER_SBIOD_LEVEL_APPLICATIONa higher layer
Currently defined Sockbuf_IO handlers in liblber include
ber_sockbuf_io_tcpThe default stream-oriented provider
ber_sockbuf_io_fdA stream-oriented provider for local IPC sockets
ber_sockbuf_io_dgramA datagram-oriented provider. This handler is only present if the liblber library was built with LDAP_CONNECTIONLESS defined.
ber_sockbuf_io_readaheadA buffering layer, usually used with a datagram provider to hide the datagram semantics from upper layers.
ber_sockbuf_io_debugA generic handler that outputs hex dumps of all traffic. This handler may be inserted multiple times at arbitrary layers to show the flow of data between other handlers.
Additional handlers may be present in libldap if support for them was enabled:
ldap_pvt_sockbuf_io_saslAn application layer handler for SASL encoding/decoding.
sb_tls_sbioA transport layer handler for SSL/TLS encoding/decoding. Note that this handler is private to the library and is not exposed in the API.
The provided handlers are all instantiated implicitly by libldap, and applications generally will not need to directly manipulate them.
OpenLDAP Software is developed and maintained by The OpenLDAP Project <http://www.openldap.org/>. OpenLDAP Software is derived from University of Michigan LDAP 3.3 Release.