SSL_CTX_set_mode manpage

Search topic Section

SSL_CTX_set_mode(3)		    OpenSSL		   SSL_CTX_set_mode(3)

       SSL_CTX_set_mode, SSL_set_mode, SSL_CTX_get_mode, SSL_get_mode -
       manipulate SSL engine mode

	#include <openssl/ssl.h>

	long SSL_CTX_set_mode(SSL_CTX *ctx, long mode);
	long SSL_set_mode(SSL *ssl, long mode);

	long SSL_CTX_get_mode(SSL_CTX *ctx);
	long SSL_get_mode(SSL *ssl);

       SSL_CTX_set_mode() adds the mode set via bitmask in mode to ctx.
       Options already set before are not cleared.

       SSL_set_mode() adds the mode set via bitmask in mode to ssl.  Options
       already set before are not cleared.

       SSL_CTX_get_mode() returns the mode set for ctx.

       SSL_get_mode() returns the mode set for ssl.

       The following mode changes are available:

	   Allow SSL_write(..., n) to return r with 0 < r < n (i.e. report
	   success when just a single record has been written). When not set
	   (the default), SSL_write() will only report success once the
	   complete chunk was written.	Once SSL_write() returns with r, r
	   bytes have been successfully written and the next call to
	   SSL_write() must only send the n-r bytes left, imitating the
	   behaviour of write().

	   Make it possible to retry SSL_write() with changed buffer location
	   (the buffer contents must stay the same). This is not the default
	   to avoid the misconception that non-blocking SSL_write() behaves
	   like non-blocking write().

	   Never bother the application with retries if the transport is
	   blocking.  If a renegotiation take place during normal operation, a
	   SSL_read(3) or SSL_write(3) would return with -1 and indicate the
	   need to retry with SSL_ERROR_WANT_READ.  In a non-blocking
	   environment applications must be prepared to handle incomplete
	   read/write operations.  In a blocking environment, applications are
	   not always prepared to deal with read/write operations returning
	   without success report. The flag SSL_MODE_AUTO_RETRY will cause
	   read/write operations to only return after the handshake and
	   successful completion.

	   When we no longer need a read buffer or a write buffer for a given
	   SSL, then release the memory we were using to hold it.  Released
	   memory is either appended to a list of unused RAM chunks on the
	   SSL_CTX, or simply freed if the list of unused chunks would become
	   longer than SSL_CTX->freelist_max_len, which defaults to 32.	 Using
	   this flag can save around 34k per idle SSL connection.  This flag
	   has no effect on SSL v2 connections, or on DTLS connections.

	   Send TLS_FALLBACK_SCSV in the ClientHello.  To be set only by
	   applications that reconnect with a downgraded protocol version; see
	   draft-ietf-tls-downgrade-scsv-00 for details.

	   DO NOT ENABLE THIS if your application attempts a normal handshake.
	   Only use this in explicit fallback retries, following the guidance
	   in draft-ietf-tls-downgrade-scsv-00.

       SSL_CTX_set_mode() and SSL_set_mode() return the new mode bitmask after
       adding mode.

       SSL_CTX_get_mode() and SSL_get_mode() return the current bitmask.

       ssl(3), SSL_read(3), SSL_write(3)

       SSL_MODE_AUTO_RETRY as been added in OpenSSL 0.9.6.

1.0.2k				  2017-01-26		   SSL_CTX_set_mode(3)