NAME
SSL_CTX_set_mode,
SSL_set_mode,
SSL_CTX_get_mode,
SSL_get_mode —
manipulate SSL engine mode
SYNOPSIS
#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);
DESCRIPTION
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.
NOTES
The following mode changes are available:
SSL_MODE_ENABLE_PARTIAL_WRITE- Allow
SSL_write(..., n) to return r with (i.e., report success when just a single record has been written). When not set (the default), SSL_write(3) will only report success once the complete chunk was written. Once SSL_write(3) returns with r, r bytes have been successfully written and the next call to SSL_write(3) must only send the n − r bytes left, imitating the behaviour of write(2). SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER- Make it possible to retry SSL_write(3) 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(3) behaves like non-blocking write(2).
SSL_MODE_AUTO_RETRY- 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 flagSSL_MODE_AUTO_RETRYwill cause read/write operations to only return after the handshake and successful completion. SSL_MODE_RELEASE_BUFFERS- 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.
RETURN VALUES
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.
SEE ALSO
HISTORY
SSL_MODE_AUTO_RETRY was added in OpenSSL
0.9.6.