ber_sockbuf_alloc,          ber_sockbuf_free,         ber_sockbuf_ctrl,
   ber_sockbuf_add_io, ber_sockbuf_remove_io, Sockbuf_IO -  OpenLDAP  LBER
   I/O infrastructure


   OpenLDAP LBER (liblber, -llber)


   #include <lber.h>

   Sockbuf *ber_sockbuf_alloc( void );

   void ber_sockbuf_free(Sockbuf *sb);

   int ber_sockbuf_ctrl(Sockbuf *sb, int opt, void *arg);

   int  ber_sockbuf_add_io(Sockbuf  *sb, Sockbuf_IO *sbio, int layer, void

   int ber_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:

          Takes a Sockbuf_IO * argument and returns 1 if the given handler
          is installed on the Sockbuf, otherwise returns 0.

          Retrieves 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.

          Sets 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.

          Toggles 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.

          Flush  (read  and  discard)  all available input on the Sockbuf.
          The return value will be 1.

          Returns non-zero if input is waiting to be read.

          Returns non-zero if the Sockbuf is ready to be written.

          Returns the maximum allowed size of  an  incoming  message;  arg
          must be a ber_len_t *.  The return value will be 1.

          Sets  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

          the lowest layer, talking directly to a network

          an intermediate layer

          a higher layer

   Currently defined Sockbuf_IO handlers in liblber include

          The default stream-oriented provider

          A stream-oriented provider for local IPC sockets

          A  datagram-oriented  provider.  This handler is only present if
          the liblber library was built with LDAP_CONNECTIONLESS defined.

          A buffering layer, usually used with a datagram provider to hide
          the datagram semantics from upper layers.

          A  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

          An application layer handler for SASL encoding/decoding.

          A 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.


   lber-decode(3), lber-encode(3), lber-types(3), ldap_get_option(3)


   OpenLDAP  Software  is developed and maintained by The OpenLDAP Project
   <>.   OpenLDAP   Software   is   derived   from
   University of Michigan LDAP 3.3 Release.


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