BIO_set_write_buf_size man page on DigitalUNIX

Man page or keyword search:  
man Server   12896 pages
apropos Keyword Search (all sections)
Output format
DigitalUNIX logo
[printable version]

BIO_s_bio(3)							  BIO_s_bio(3)

       BIO_s_bio,  BIO_make_bio_pair,  BIO_destroy_bio_pair,  BIO_shutdown_wr,
       BIO_set_write_buf_size,	BIO_get_write_buf_size,	 BIO_get_write_guaran‐
       tee,	    BIO_ctrl_get_write_guarantee,	 BIO_get_read_request,
       BIO_ctrl_reset_read_request - BIO pair BIO

       #include <openssl/bio.h>

       BIO_METHOD *BIO_s_bio(
	       void	   );	      #define	      BIO_make_bio_pair(b1,b2)
       (int)BIO_ctrl(b1,BIO_C_MAKE_BIO_PAIR,0,b2)		       #define

       #define BIO_shutdown_wr(b) (int)BIO_ctrl(b, BIO_C_SHUTDOWN_WR, 0, NULL)

       #define					BIO_set_write_buf_size(b,size)
       (int)BIO_ctrl(b,BIO_C_SET_WRITE_BUF_SIZE,size,NULL)	       #define

       int BIO_new_bio_pair(
	       BIO **bio1,
	       size_t writebuf1,
	       BIO **bio2,
	       size_t	writebuf2   );	 #define    BIO_get_write_guarantee(b)

       size_t BIO_ctrl_get_write_guarantee(
	       BIO	 *b	  );	  #define      BIO_get_read_request(b)

       size_t BIO_ctrl_get_read_request(
	       BIO *b ); int BIO_ctrl_reset_read_request(
	       BIO *b );

       The BIO_s_bio() function returns the method for a BIO pair. A BIO  pair
       is  a pair of source/sink BIOs where data written to either half of the
       pair is buffered and can be read from the other half. Both halves  must
       usually	by  handled by the same application thread since no locking is
       done on the internal data structures.

       Since BIO chains typically end in a source/sink BIO it is  possible  to
       make this one half of a BIO pair and have all the data processed by the
       chain under application control.

       One typical use of BIO pairs is to place TLS/SSL I/O under  application
       control,	 this  can  be	used  when the application wishes to use a non
       standard transport for TLS/SSL or the normal socket routines are	 inap‐

       Calls  to  BIO_read() will read data from the buffer or request a retry
       if no data is available.

       Calls to BIO_write() will place data in the buffer or request  a	 retry
       if the buffer is full.

       The  standard  calls  BIO_ctrl_pending() and BIO_ctrl_wpending() can be
       used to determine the amount of pending data in the read or write  buf‐

       The BIO_reset() function clears any data in the write buffer.

       The  BIO_make_bio_pair()	 function  joins two separate BIOs into a con‐
       nected pair.

       The BIO_destroy_pair() function destroys the  association  between  two
       connected  BIOs.	 Freeing  up  any  half of the pair will automatically
       destroy the association.

       The BIO_shutdown_wr() is used to close down a BIO b. After this call no
       further	writes	on BIO b are allowed. They will return an error. Reads
       on the other half of the pair will return any pending data or EOF  when
       all pending data has been read.

       The BIO_set_write_buf_size() function sets the write buffer size of BIO
       b to size. If the size is not initialized a default value is used. This
       is currently 17K, sufficient for a maximum size TLS record.

       The  BIO_get_write_buf_size()  function	returns	 the size of the write

       The  BIO_new_bio_pair()	function  combines  the	 calls	to  BIO_new(),
       BIO_make_bio_pair(), and BIO_set_write_buf_size() to create a connected
       pair of BIOs, bio1 and bio2, with  write	 buffer	 sizes	writebuf1  and
       writebuf2. If either size is zero then the default size is used.

       BIO_get_write_guarantee() and BIO_ctrl_get_write_guarantee() return the
       maximum length of data that can be written to the BIO.	Writes	larger
       than  this  value  will	return	a value from BIO_write() less than the
       amount  requested  or,  if  the	buffer	is  full  request,  a	retry.
       BIO_ctrl_get_write_guarantee()	   is	   a	  function     whereas
       BIO_get_write_guarantee() is a macro.

       BIO_get_read_request()  and  BIO_ctrl_get_read_request()	  return   the
       amount of data requested, or the buffer size if it is less, if the last
       read attempt at the other half of the BIO pair failed due to  an	 empty
       buffer.	 This can be used to determine how much data should be written
       to the BIO so the next read  will  succeed.  This  is  most  useful  in
       TLS/SSL	applications where the amount of data read is usually meaning‐
       ful rather than just a buffer size. After a successful read  this  call
       will  return  zero.   It	 also  will return zero once new data has been
       written	 satisfying   the   read    request    or    part    of	   it.
       BIO_get_read_request()	never  returns	an  amount  larger  than  that
       returned by BIO_get_write_guarantee().

       BIO_ctrl_reset_read_request() can also  be  used	 to  reset  the	 value
       returned by BIO_get_read_request() to zero.

       Both halves of a BIO pair should be freed. Even if one half is implicit
       freed due to a BIO_free_all() or SSL_free() call, the other half	 needs
       to be freed.

       When  used  in bidirectional applications, such as TLS/SSL, care should
       be taken to flush any data in the write buffer. This  can  be  done  by
       calling BIO_pending() on the other half of the pair and, if any data is
       pending, reading it and sending it to the  underlying  transport.  This
       must  be	 done  before any normal processing, such as calling select(),
       due to a request and BIO_should_read() being true.

       To see why this is important consider a case where a  request  is  sent
       using  BIO_write()  and a response read with BIO_read(), this can occur
       during an TLS/SSL handshake for example.	 BIO_write() will succeed  and
       place  data  in	the  write buffer.  BIO_read() will initially fail and
       BIO_should_read() will be true. If the application then waits for  data
       to  be  available on the underlying transport before flushing the write
       buffer it will never succeed because the request was never sent.

       Functions:	   SSL_set_bio(3),	     ssl(3),	       bio(3),
       BIO_ctrl_get_read_request(3), BIO_new_bio_pair(3), BIO_should_retry(3),


List of man pages available for DigitalUNIX

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net